Fix

.gitignore

@@ -1,3 +1,4 @@
 /shell2.exe
 /BOT_PLAN.md
 /SECURITY_REVIEW.md
+/DragonCoreSSH-NewWEB.zip

README.md

@@ -66,6 +66,18 @@ Para configurações XHTTP antigas, carregue a configuração visual e clique em
 
 A confirmação dessa migração é exibida dentro do próprio painel. Se a gravação falhar, o inbound SSH temporário é removido do rascunho e o inbound antigo permanece intacto, permitindo tentar novamente após corrigir o erro exibido.
 
+### Cota de tráfego e proteção de recursos
+
+Contas SSH e clientes VLESS/VMess do modo nativo podem usar `data_quota_bytes` com ação `block` ou `throttle`. O botão **Reset/Zerar tráfego** limpa apenas os contadores; não renova validade, senha ou configuração da conta. O valor `max_conns` é aplicado no momento em que o usuário VLESS/VMess é autenticado e vale em conjunto para TCP, UDP, WebSocket, XHTTP e conexões Mux (uma conexão Mux autenticada conta como uma conexão, independentemente dos streams filhos).
+
+O runtime nativo também possui limites globais para impedir crescimento sem controle de sockets, goroutines e sessões HTTP:
+
+- `max_concurrent_connections`: conexões de transporte TCP/TLS/WebSocket/XHTTP; padrão `32768`;
+- `max_concurrent_xhttp_requests`: mantido apenas para compatibilidade de configuração; o limite de requisições web fica desativado (`-1`) no XHTTP;
+- `xhttp_max_sessions`: sessões XHTTP ativas; padrão `32768`.
+
+Esses campos ficam em **Configurações → Xray → Native Xray scale tuning**. O XHTTP é tratado como transporte VPN: rajadas de packet-up usam backpressure cancelável e buffers de bytes limitados, sem respostas `429` nem semântica de “too many requests”. Ao atingir o teto de transporte, novos sockets permanecem no backlog do kernel em vez de serem aceitos e resetados. Conexões HTTP/2 mantêm um limite de fluxo de 1024 streams simultâneos por conexão. Cada transporte Mux aceita no máximo 64 sessões filhas, com limite global padrão de 32768. Sockets WebSocket incompletos têm timeout de handshake, conexões HTTP ociosas têm timeout, e parar/reiniciar o Xray nativo fecha conexões e sessões existentes. Atualizações de tráfego e de conexões ativas são agregadas e persistidas em lote a cada cinco segundos, sem criar uma goroutine ou consulta PostgreSQL por conexão. Entradas pendentes de usuários removidos são descartadas para manter os mapas de retry limitados ao conjunto atual de contas.
+
 ### Requisitos
 
 - Servidor Linux com `systemd`
@@ -595,6 +607,18 @@ For older XHTTP configurations, load the visual configuration and click **Enable
 
 The migration confirmation is rendered inside the panel. If saving fails, the temporary SSH inbound is removed from the draft and the old inbound remains intact, so the operation can be retried after fixing the displayed error.
 
+### Traffic quotas and resource protection
+
+SSH accounts and native-mode VLESS/VMess clients can use `data_quota_bytes` with either the `block` or `throttle` action. The **Reset traffic** action clears only usage counters; it does not renew expiry, change a password, or alter account settings. `max_conns` is enforced when a native VLESS/VMess user is authenticated and is shared across TCP, UDP, WebSocket, XHTTP, and Mux transports (one authenticated Mux transport counts as one connection, regardless of its child streams).
+
+The native runtime also has global ceilings that prevent unbounded socket, goroutine, and HTTP-session growth:
+
+- `max_concurrent_connections`: TCP/TLS/WebSocket/XHTTP transport connections; default `32768`;
+- `max_concurrent_xhttp_requests`: retained for configuration compatibility; the web-request cap is disabled (`-1`) for XHTTP;
+- `xhttp_max_sessions`: active XHTTP sessions; default `32768`.
+
+These fields are available under **Settings → Xray → Native Xray scale tuning**. XHTTP is treated as VPN transport traffic: packet-up bursts use cancelable backpressure and bounded byte buffers, with no `429` or “too many requests” behavior. At the transport ceiling, new sockets remain in the kernel backlog instead of being accepted and reset. HTTP/2 connections retain a 1024-stream flow-control guard per connection. Each Mux transport accepts at most 64 child sessions, with a default global ceiling of 32768. Incomplete WebSocket handshakes time out, idle HTTP connections time out, and stopping/restarting native Xray closes existing transports and XHTTP sessions. Traffic and active-connection changes are aggregated and written in five-second batches rather than creating a PostgreSQL query or goroutine for every connection. Pending retry entries for deleted clients are removed so retry maps stay bounded by the current account set.
+
 ### Requirements
 
 - Linux server with `systemd`

admin/assets/app.css

@@ -750,3 +750,10 @@ select:disabled {
 @media(max-width:1180px){.bot-overview-grid{grid-template-columns:repeat(2,minmax(0,1fr));}.bot-section-nav{grid-template-columns:repeat(3,minmax(0,1fr));}.bot-master-detail{grid-template-columns:1fr;}.bot-editor-card{position:static;}.bot-nav-shell{top:78px;}}
 @media(max-width:760px){.bot-hero{padding:20px;border-radius:22px;}.bot-hero h2{font-size:1.55rem;}.bot-hero-actions{position:relative;right:auto;top:auto;max-width:none;justify-content:flex-start;margin-top:16px;}.bot-overview-grid{grid-template-columns:1fr 1fr;margin-top:18px;}.bot-section-nav{display:none;}.bot-section-select{display:block;}.bot-nav-shell{top:76px;}.bot-config-grid,.bot-message-grid{grid-template-columns:1fr;}.bot-section-heading{align-items:flex-start;flex-direction:column;}.bot-section-heading>.card-actions{width:100%;justify-content:flex-start;}.bot-master-detail{display:block;}.bot-master-detail>.card+.card{margin-top:14px!important;}.bot-save-row{align-items:flex-start;flex-direction:column;}}
 @media(max-width:460px){.bot-overview-grid{grid-template-columns:1fr;}.bot-overview-card{padding:11px 12px;}.bot-hero-actions .btn{width:100%;}.bot-section-heading .btn{width:100%;}.bot-copy-row{align-items:stretch;flex-direction:column;}.bot-copy-row .btn{width:100%;}}
+
+/* Sortable SSH user table headers */
+th[data-sort-key]{cursor:pointer;user-select:none;white-space:nowrap;transition:color .12s ease;}
+th[data-sort-key]:hover{color:var(--accent);}
+th[data-sort-key]::after{content:"";display:inline-block;width:.9em;font-size:.72em;opacity:.85;}
+th[data-sort-key].sort-asc::after{content:" \25B2";}
+th[data-sort-key].sort-desc::after{content:" \25BC";}

admin/assets/js/01-core.js

@@ -172,6 +172,24 @@ Object.assign(I18N_TEXT["pt-BR"], {
   "Reseller areas":"Áreas de revendedores","Reseller area":"Área de revendedores","Create reseller":"Criar revendedor","Edit reseller":"Editar revendedor","Registered resellers":"Revendedores cadastrados","Reseller list section copy":"Consulte cotas, consumo compartilhado, validade e situação de cada parceiro.","Reseller create section copy":"Defina login, limite compartilhado, validade e acesso em uma tela dedicada.","Reseller saved successfully.":"Revendedor salvo com sucesso.",
   "Configuration areas":"Áreas de configuração","Configuration area":"Área de configuração","Network and SSH":"Rede e SSH","SlowDNS / DNSTT":"SlowDNS / DNSTT","TLS forwarders":"Encaminhadores TLS","01 · Base":"01 · Base","02 · DNS tunnel":"02 · Túnel DNS","03 · UDP":"03 · UDP","04 · Security":"04 · Segurança","05 · Core":"05 · Core","Network and SSH section copy":"Configure listeners, limites padrão, tempo ocioso e o banner de conexão.","SlowDNS section copy":"Gerencie domínios, DNS local, capacidade, filas e reinício controlado.","UDP section copy":"Defina listener, capacidade, expiração de mapa e reinício do serviço.","TLS section copy":"Crie listeners TLS com certificado automático, colado ou armazenado em arquivo.","Xray core section copy":"Ative o core, escolha o runtime e aplique os ajustes nativos seguros."
 });
+Object.assign(I18N_TEXT["en-US"], {
+  "Reset":"Reset","Reset traffic":"Reset traffic","Reset SSH traffic":"Reset SSH traffic","Reset Xray traffic":"Reset Xray traffic",
+  "Reset traffic for user \"{name}\"?":"Reset traffic for user \"{name}\"?","Reset traffic for client {id}…?":"Reset traffic for client {id}…?",
+  "Current uploaded and downloaded usage will return to zero. The account, password, expiry and quota remain unchanged.":"Current uploaded and downloaded usage will return to zero. The account, password, expiry and quota remain unchanged.",
+  "Current uploaded and downloaded usage will return to zero. The account, expiry and quota remain unchanged.":"Current uploaded and downloaded usage will return to zero. The account, expiry and quota remain unchanged.",
+  "Resetting traffic for {name}…":"Resetting traffic for {name}…","Resetting traffic for client {id}…":"Resetting traffic for client {id}…",
+  "Traffic reset successfully.":"Traffic reset successfully.","Xray traffic reset successfully.":"Xray traffic reset successfully.",
+  "Could not reset traffic: {error}":"Could not reset traffic: {error}","Reset traffic counter":"Reset traffic counter"
+});
+Object.assign(I18N_TEXT["pt-BR"], {
+  "Reset":"Zerar","Reset traffic":"Zerar tráfego","Reset SSH traffic":"Zerar tráfego SSH","Reset Xray traffic":"Zerar tráfego Xray",
+  "Reset traffic for user \"{name}\"?":"Zerar o tráfego do usuário \"{name}\"?","Reset traffic for client {id}…?":"Zerar o tráfego do cliente {id}…?",
+  "Current uploaded and downloaded usage will return to zero. The account, password, expiry and quota remain unchanged.":"O consumo de upload e download voltará para zero. A conta, senha, validade e cota não serão alteradas.",
+  "Current uploaded and downloaded usage will return to zero. The account, expiry and quota remain unchanged.":"O consumo de upload e download voltará para zero. A conta, validade e cota não serão alteradas.",
+  "Resetting traffic for {name}…":"Zerando o tráfego de {name}…","Resetting traffic for client {id}…":"Zerando o tráfego do cliente {id}…",
+  "Traffic reset successfully.":"Tráfego zerado com sucesso.","Xray traffic reset successfully.":"Tráfego Xray zerado com sucesso.",
+  "Could not reset traffic: {error}":"Não foi possível zerar o tráfego: {error}","Reset traffic counter":"Zerar contador de tráfego"
+});
 const I18N_REVERSE = Object.fromEntries(SUPPORTED_LANGS.map(lang => [lang, Object.fromEntries(Object.entries(I18N_TEXT[lang] || {}).map(([k, v]) => [v, k]))]));
 let currentLang = detectInitialLanguage();
 let i18nTranslating = false;
@@ -683,7 +701,12 @@ function clientTrafficHTML(c) {
   const up = Number(c.uplink_bytes || 0);
   const down = Number(c.downlink_bytes || 0);
   const total = Number(c.total_bytes || (up + down) || 0);
-  return `${escapeHTML(formatBytes(total))}<div class="hint">↑ ${escapeHTML(formatBytes(up))} · ↓ ${escapeHTML(formatBytes(down))}</div>`;
+  const quota = Number(c.data_quota_bytes || 0);
+  const quotaLabel = quota > 0 ? formatBytes(quota) : "∞";
+  const state = c.quota_exceeded
+    ? (c.quota_action === "throttle" ? ` · ${t("throttled")}` : ` · ${t("blocked")}`)
+    : "";
+  return `${escapeHTML(formatBytes(total))} / ${escapeHTML(quotaLabel)}${escapeHTML(state)}<div class="hint">↑ ${escapeHTML(formatBytes(up))} · ↓ ${escapeHTML(formatBytes(down))}</div>`;
 }
 
 function updateCell(row, name, html) {

admin/assets/js/03-ssh-users.js

@@ -9,6 +9,10 @@ cancelUserBtn.addEventListener("click", () => {
 function prepareNewSSHUser() {
   userForm.reset();
   fTotpPeriod.value = 60; fTotpWindow.value = 1; fTotpDigits.value = 6;
+  fQuotaAction.value = "block";
+  fQuotaThrottle.value = 1;
+  fUsageDisplay.value = "0 B";
+  fResetUsage.checked = false;
   const heading = document.getElementById("userFormHeading");
   const title = document.getElementById("userFormTitle");
   if (heading) heading.textContent = t("Create user");
@@ -57,7 +61,90 @@ async function loadUsersSilent() {
   }
 }
 
+// ---- Column sorting (click a header to sort) ----
+// Value extractor per sortable column. Numbers sort numerically, strings
+// alphabetically; online counts as 1 so "status" groups online users together.
+const USER_SORT_EXTRACT = {
+  username: u => String(u.username || "").toLowerCase(),
+  status:   u => (u.active_conns || 0) > 0 ? 1 : 0,
+  auth:     u => u.use_pam ? "pam" : (u.totp_enabled ? (u.allow_static_password ? "totp+pw" : "totp") : "password"),
+  conn:     u => u.active_conns || 0,
+  max:      u => u.max_connections || 0,
+  up:       u => u.limit_mbps_up || 0,
+  down:     u => u.limit_mbps_down || 0,
+  usage:    u => Number(u.total_bytes || ((u.total_uplink_bytes || 0) + (u.total_downlink_bytes || 0)) || 0),
+  expires:  u => u.expires_at ? new Date(u.expires_at).getTime() : Infinity,
+  owner:    u => String(u.owner_username || "").toLowerCase(),
+};
+// Columns that default to descending on first click (most/online first).
+const USER_SORT_DEFAULT_DESC = new Set(["status", "conn", "max", "up", "down", "usage"]);
+
+let userSort = { key: "username", dir: "asc" };
+let lastUsersData = [];
+
+function sortUsers(list) {
+  const ext = USER_SORT_EXTRACT[userSort.key] || USER_SORT_EXTRACT.username;
+  const dir = userSort.dir === "desc" ? -1 : 1;
+  return list.slice().sort((a, b) => {
+    const va = ext(a), vb = ext(b);
+    let cmp;
+    if (typeof va === "number" && typeof vb === "number") cmp = va - vb;
+    else cmp = String(va).localeCompare(String(vb));
+    // Stable tie-break by username so equal rows never shuffle between polls.
+    if (cmp === 0) cmp = String(a.username || "").localeCompare(String(b.username || ""));
+    return cmp * dir;
+  });
+}
+
+function updateSortIndicators() {
+  const table = usersBody && usersBody.closest("table");
+  if (!table) return;
+  table.querySelectorAll("th[data-sort-key]").forEach(th => {
+    th.classList.remove("sort-asc", "sort-desc");
+    if (th.getAttribute("data-sort-key") === userSort.key) {
+      th.classList.add(userSort.dir === "asc" ? "sort-asc" : "sort-desc");
+    }
+  });
+}
+
+function setUserSort(key) {
+  if (!USER_SORT_EXTRACT[key]) return;
+  if (userSort.key === key) {
+    userSort.dir = userSort.dir === "asc" ? "desc" : "asc";
+  } else {
+    userSort.key = key;
+    userSort.dir = USER_SORT_DEFAULT_DESC.has(key) ? "desc" : "asc";
+  }
+  updateSortIndicators();
+  renderUsers(lastUsersData);
+}
+
+(function initUserSortHeaders() {
+  const table = usersBody && usersBody.closest("table");
+  if (!table) return;
+  table.querySelectorAll("th[data-sort-key]").forEach(th => {
+    th.addEventListener("click", () => setUserSort(th.getAttribute("data-sort-key")));
+  });
+  updateSortIndicators();
+})();
+
+function sshTrafficHTML(u) {
+  const up = Number(u.total_uplink_bytes || 0);
+  const down = Number(u.total_downlink_bytes || 0);
+  const total = Number(u.total_bytes || (up + down) || 0);
+  const quota = Number(u.data_quota_bytes || 0);
+  const quotaLabel = quota > 0 ? formatBytes(quota) : "∞";
+  const state = u.quota_exceeded
+    ? (u.quota_action === "throttle" ? ` · ${t("throttled")}` : ` · ${t("blocked")}`)
+    : "";
+  return `${escapeHTML(formatBytes(total))} / ${escapeHTML(quotaLabel)}${escapeHTML(state)}<div class="hint">↑ ${escapeHTML(formatBytes(up))} · ↓ ${escapeHTML(formatBytes(down))}</div>`;
+}
+
 function renderUsers(users) {
+  // Cache the raw list so a header click can re-sort without refetching, and
+  // order by the active column so rows don't shuffle on each live poll.
+  lastUsersData = users || [];
+  users = sortUsers(lastUsersData);
   updateDashboardFromUsers(users);
   const isSA = currentRole === "superadmin";
   userCountChip.textContent = users.length;
@@ -73,17 +160,19 @@ function renderUsers(users) {
     const cells = [
       u.username,
       on ? `<span class="badge-on">${t("online")}</span>` : `<span class="badge-off">${t("idle")}</span>`,
-      u.totp_enabled ? (u.allow_static_password ? "TOTP+pw" : "TOTP") : "Password",
+      u.use_pam ? "PAM" : (u.totp_enabled ? (u.allow_static_password ? "TOTP+pw" : "TOTP") : "Password"),
       u.active_conns ?? 0,
       u.max_connections || 0,
       u.limit_mbps_up || 0,
       u.limit_mbps_down || 0,
+      sshTrafficHTML(u),
       u.expires_at ? fmtDate(u.expires_at) : "—",
     ];
     if (isSA) cells.push(u.owner_username || "—");
     cells.forEach((c, i) => {
       const td = document.createElement("td");
-      if (i === 1) td.innerHTML = c; else td.textContent = c;
+      if (i === 1 || i === 7) td.innerHTML = c; else td.textContent = c;
+      if (i === 7) td.style.fontSize = ".7rem";
       tr.appendChild(td);
     });
     const tdA = document.createElement("td");
@@ -91,12 +180,18 @@ function renderUsers(users) {
       className:"btn btn-ghost btn-sm", textContent:t("Edit"),
       onclick: () => fillUserForm(u),
     });
+    const resetBtn = Object.assign(document.createElement("button"), {
+      className:"btn btn-warn btn-sm", textContent:t("Reset"),
+      style: "margin-left:4px;",
+      title: t("Reset traffic"),
+      onclick: () => resetUserTraffic(u.username, resetBtn),
+    });
     const delBtn = Object.assign(document.createElement("button"), {
       className:"btn btn-danger btn-sm", textContent:t("Del"),
       style: "margin-left:4px;",
       onclick: () => deleteUser(u.username),
     });
-    tdA.append(editBtn, delBtn);
+    tdA.append(editBtn, resetBtn, delBtn);
     tr.appendChild(tdA);
     usersBody.appendChild(tr);
   });
@@ -124,6 +219,12 @@ function fillUserForm(u) {
   fMaxConn.value        = u.max_connections || "";
   fUp.value             = u.limit_mbps_up || "";
   fDown.value           = u.limit_mbps_down || "";
+  fQuotaGB.value        = u.data_quota_bytes ? (Number(u.data_quota_bytes) / (1024 ** 3)).toFixed(2).replace(/\.00$/, "") : "0";
+  fQuotaAction.value    = u.quota_action === "throttle" ? "throttle" : "block";
+  fQuotaThrottle.value  = u.quota_throttle_mbps || 1;
+  const totalBytes      = Number(u.total_bytes || ((u.total_uplink_bytes || 0) + (u.total_downlink_bytes || 0)) || 0);
+  fUsageDisplay.value   = `${formatBytes(totalBytes)} (↑ ${formatBytes(u.total_uplink_bytes || 0)} · ↓ ${formatBytes(u.total_downlink_bytes || 0)})`;
+  fResetUsage.checked   = false;
   fExpires.value        = u.expires_at ? localFromISO(u.expires_at) : "";
   const heading = document.getElementById("userFormHeading");
   const title = document.getElementById("userFormTitle");
@@ -148,6 +249,10 @@ userForm.addEventListener("submit", async e => {
     expires_at: isoFromLocal(fExpires.value),
     limit_mbps_up:   parseInt(fUp.value||"0",10),
     limit_mbps_down: parseInt(fDown.value||"0",10),
+    data_quota_bytes: Math.round((parseFloat(fQuotaGB.value || "0") || 0) * (1024 ** 3)),
+    quota_action: fQuotaAction.value === "throttle" ? "throttle" : "block",
+    quota_throttle_mbps: parseInt(fQuotaThrottle.value || "1", 10) || 1,
+    reset_usage: !!fResetUsage.checked,
     server_id: selectedSSHServer(),
   };
   try {
@@ -155,6 +260,7 @@ userForm.addEventListener("submit", async e => {
     if (!res.ok) throw new Error(await res.text());
     userStatus.textContent = t("Saved.");
     fPassword.value = "";
+    fResetUsage.checked = false;
     loadUsers();
     if (currentRole === "reseller") loadMe();
     showPanelToast(t("SSH user saved successfully."), "success", t("SSH / SlowDNS"));
@@ -167,6 +273,37 @@ userForm.addEventListener("submit", async e => {
   }
 });
 
+async function resetUserTraffic(username, button) {
+  const accepted = await panelConfirm({
+    tone:"warning", icon:"↺", title:t("Reset SSH traffic"),
+    message:t("Reset traffic for user \"{name}\"?", {name: username}),
+    detail:t("Current uploaded and downloaded usage will return to zero. The account, password, expiry and quota remain unchanged."),
+    confirmLabel:t("Reset traffic"),
+  });
+  if (!accepted) return;
+  const previousDisabled = !!button?.disabled;
+  if (button) button.disabled = true;
+  userStatus.textContent = t("Resetting traffic for {name}…", {name: username});
+  try {
+    const res = await api("/api/users/reset-traffic", {
+      method:"POST",
+      body: JSON.stringify({ username, server_id:selectedSSHServer() }),
+    });
+    if (!res.ok) throw new Error((await res.text()) || "reset failed");
+    userStatus.textContent = t("Traffic reset successfully.");
+    showPanelToast(t("Traffic reset successfully."), "success", t("SSH / SlowDNS"));
+    await loadUsers();
+  } catch (e) {
+    if (e.message === "auth") doAuthError();
+    else {
+      userStatus.textContent = t("Could not reset traffic: {error}", {error:e.message});
+      showPanelToast(t("Could not reset traffic: {error}", {error:e.message}), "error", t("SSH / SlowDNS"));
+    }
+  } finally {
+    if (button) button.disabled = previousDisabled;
+  }
+}
+
 async function deleteUser(username) {
   const accepted = await panelConfirm({
     tone:"danger", icon:"×", title:t("Delete SSH account"),

admin/assets/js/04-xray.js

@@ -244,12 +244,18 @@ function renderInbounds(inbounds, options = {}) {
         editBtn.style.marginLeft = "4px";
         editBtn.textContent = t("Edit");
         editBtn.onclick = () => openEditXrayClient(ib.tag, c);
+        const resetBtn = document.createElement("button");
+        resetBtn.className = "btn btn-warn btn-sm";
+        resetBtn.style.marginLeft = "4px";
+        resetBtn.textContent = t("Reset");
+        resetBtn.title = t("Reset traffic");
+        resetBtn.onclick = () => resetXrayClientTraffic(c.id, resetBtn);
         const delBtn = document.createElement("button");
         delBtn.className = "btn btn-danger btn-sm";
         delBtn.style.marginLeft = "4px";
         delBtn.textContent = t("Del");
         delBtn.onclick = () => removeClient(ib.tag, c.id);
-        actTd.append(copyBtn, editBtn, delBtn);
+        actTd.append(copyBtn, editBtn, resetBtn, delBtn);
         tr.appendChild(actTd);
         tbody.appendChild(tr);
       });
@@ -325,6 +331,12 @@ function prepareXrayClientCreator(preferredTag = "") {
   if (uuid) uuid.value = genUUID();
   const maxConns = document.getElementById("xCreateMaxConns");
   if (maxConns) maxConns.value = "0";
+  const quotaGB = document.getElementById("xCreateQuotaGB");
+  if (quotaGB) quotaGB.value = "0";
+  const quotaAction = document.getElementById("xCreateQuotaAction");
+  if (quotaAction) quotaAction.value = "block";
+  const quotaThrottle = document.getElementById("xCreateQuotaThrottle");
+  if (quotaThrottle) quotaThrottle.value = "1";
   const status = document.getElementById("xCreateClientStatus");
   if (status) status.textContent = xrayCreatorInbounds.length ? t("Ready to create a new Xray client.") : t("Waiting for a compatible inbound.");
   updateXrayCreatorInboundLabel();
@@ -351,6 +363,9 @@ async function submitXrayClientCreator(event) {
     name: (document.getElementById("xCreateName")?.value || "").trim(),
     expires_at: isoFromLocal(document.getElementById("xCreateExpiry")?.value || ""),
     max_connections: parseInt(document.getElementById("xCreateMaxConns")?.value || "0", 10) || 0,
+    data_quota_bytes: Math.round((parseFloat(document.getElementById("xCreateQuotaGB")?.value || "0") || 0) * (1024 ** 3)),
+    quota_action: document.getElementById("xCreateQuotaAction")?.value === "throttle" ? "throttle" : "block",
+    quota_throttle_mbps: parseInt(document.getElementById("xCreateQuotaThrottle")?.value || "1", 10) || 1,
     server_id: selectedXrayServer(),
   };
   if (button) button.disabled = true;
@@ -385,6 +400,44 @@ async function submitXrayClientCreator(event) {
   }
 }
 
+async function resetXrayClientTraffic(uuid, button) {
+  const shortID = String(uuid || "").slice(0, 8);
+  const accepted = await panelConfirm({
+    tone:"warning", icon:"↺", title:t("Reset Xray traffic"),
+    message:t("Reset traffic for client {id}…?", {id:shortID}),
+    detail:t("Current uploaded and downloaded usage will return to zero. The account, expiry and quota remain unchanged."),
+    confirmLabel:t("Reset traffic"),
+  });
+  if (!accepted) return;
+  const previousDisabled = !!button?.disabled;
+  if (button) button.disabled = true;
+  xStatus.textContent = t("Resetting traffic for client {id}…", {id:shortID});
+  try {
+    const res = await api("/api/xray/clients/reset-traffic", {
+      method:"POST",
+      body:JSON.stringify({ uuid, server_id:selectedXrayServer() }),
+    });
+    if (!res.ok) throw new Error((await res.text()) || "reset failed");
+    xStatus.textContent = t("Xray traffic reset successfully.");
+    showPanelToast(t("Xray traffic reset successfully."), "success", t("Xray user"));
+    if (editingXrayClientId === uuid) {
+      const usage = document.getElementById("editXrayUsage");
+      if (usage) usage.value = "0 B (↑ 0 B · ↓ 0 B)";
+      const resetUsage = document.getElementById("editXrayResetUsage");
+      if (resetUsage) resetUsage.checked = false;
+    }
+    await loadInbounds({ force:true });
+  } catch (e) {
+    if (e.message === "auth") doAuthError();
+    else {
+      xStatus.textContent = t("Could not reset traffic: {error}", {error:e.message});
+      showPanelToast(t("Could not reset traffic: {error}", {error:e.message}), "error", t("Xray user"));
+    }
+  } finally {
+    if (button) button.disabled = previousDisabled;
+  }
+}
+
 async function removeClient(tag, uuid) {
   const accepted = await panelConfirm({
     tone:"danger", icon:"×", title:t("Remove Xray client"),

admin/assets/js/06-servers.js

@@ -418,6 +418,7 @@ async function loadManagedServerConfig(id) {
     document.getElementById("managedCfgSSHIdleTimeout").value = c.ssh_idle_timeout || "0s";
     document.getElementById("managedCfgQuiet").checked = !!c.quiet;
     document.getElementById("managedCfgUserCount").checked = !!c.user_count;
+    document.getElementById("managedCfgPamAuth").checked = !!c.pam_auth_enabled;
     document.getElementById("managedCfgBanner").value = c.banner || "";
 
     const hasDnstt = !!c.dnstt;
@@ -487,6 +488,7 @@ function managedConfigFromForm() {
     ssh_idle_timeout: document.getElementById("managedCfgSSHIdleTimeout").value.trim() || "0s",
     quiet: document.getElementById("managedCfgQuiet").checked,
     user_count: document.getElementById("managedCfgUserCount").checked,
+    pam_auth_enabled: document.getElementById("managedCfgPamAuth").checked,
     banner: document.getElementById("managedCfgBanner").value,
     banner_file: "/opt/sshpanel/banner.txt",
     dnstt: document.getElementById("managedCfgDnsttEnabled").checked ? {

admin/assets/js/08-server-config.js

@@ -36,11 +36,17 @@ const XRAY_NATIVE_TUNING_DEFAULTS = {
   safe: {
     runtime_gomaxprocs: 0,
     mux_global_sessions: 8192,
+    max_concurrent_connections: 4096,
+    max_concurrent_xhttp_requests: 8192,
+    xhttp_max_sessions: 4096,
     trace_packets: false,
   },
   "2k": {
     runtime_gomaxprocs: 0,
     mux_global_sessions: 32768,
+    max_concurrent_connections: 8192,
+    max_concurrent_xhttp_requests: 16384,
+    xhttp_max_sessions: 8192,
     trace_packets: false,
   },
 };
@@ -48,6 +54,9 @@ const XRAY_NATIVE_TUNING_DEFAULTS = {
 const XRAY_NATIVE_TUNING_FIELDS = {
   runtime_gomaxprocs: "cfgXrayRuntimeGomaxprocs",
   mux_global_sessions: "cfgXrayMuxGlobalSessions",
+  max_concurrent_connections: "cfgXrayMaxConnections",
+  max_concurrent_xhttp_requests: "cfgXrayMaxXHTTPRequests",
+  xhttp_max_sessions: "cfgXrayMaxXHTTPSessions",
 };
 
 function setXrayNativeTuningDefaults(profile = "2k") {
@@ -99,6 +108,7 @@ async function loadServerConfig() {
     document.getElementById("cfgSSHIdleTimeout").value = c.ssh_idle_timeout || "0s";
     document.getElementById("cfgQuiet").checked      = !!c.quiet;
     document.getElementById("cfgUserCount").checked  = !!c.user_count;
+    document.getElementById("cfgPamAuth").checked    = !!c.pam_auth_enabled;
 
     // Banner
     document.getElementById("cfgBanner").value       = c.banner || "";
@@ -182,6 +192,7 @@ async function saveServerConfig() {
     ssh_idle_timeout:         document.getElementById("cfgSSHIdleTimeout").value.trim() || "0s",
     quiet:      document.getElementById("cfgQuiet").checked,
     user_count: document.getElementById("cfgUserCount").checked,
+    pam_auth_enabled: document.getElementById("cfgPamAuth").checked,
     banner:      document.getElementById("cfgBanner").value,
     banner_file: "/opt/sshpanel/banner.txt",
     dnstt: document.getElementById("cfgDnsttEnabled").checked ? {

admin/assets/js/09-xray-wizard.js

@@ -6,6 +6,11 @@ function openEditXrayClient(tag, client) {
   document.getElementById("editXrayEmail").value   = client.email || "";
   document.getElementById("editXrayExpiry").value  = client.expires_at ? localFromISO(client.expires_at) : "";
   document.getElementById("editXrayMaxConns").value = client.max_conns || 0;
+  document.getElementById("editXrayQuotaGB").value = client.data_quota_bytes ? (Number(client.data_quota_bytes) / (1024 ** 3)).toFixed(2).replace(/\.00$/, "") : "0";
+  document.getElementById("editXrayQuotaAction").value = client.quota_action === "throttle" ? "throttle" : "block";
+  document.getElementById("editXrayQuotaThrottle").value = client.quota_throttle_mbps || 1;
+  document.getElementById("editXrayUsage").value = `${formatBytes(client.total_bytes || 0)} (↑ ${formatBytes(client.uplink_bytes || 0)} · ↓ ${formatBytes(client.downlink_bytes || 0)})`;
+  document.getElementById("editXrayResetUsage").checked = false;
   document.getElementById("editXrayClientStatus").textContent = "";
   document.getElementById("editXrayClientPanel").classList.remove("hidden");
   document.getElementById("editXrayClientPanel").scrollIntoView({ behavior:"smooth", block:"nearest" });
@@ -26,6 +31,10 @@ async function saveEditXrayClient() {
     email:           document.getElementById("editXrayEmail").value.trim(),
     expires_at:      isoFromLocal(document.getElementById("editXrayExpiry").value),
     max_connections: parseInt(document.getElementById("editXrayMaxConns").value || "0", 10),
+    data_quota_bytes: Math.round((parseFloat(document.getElementById("editXrayQuotaGB").value || "0") || 0) * (1024 ** 3)),
+    quota_action: document.getElementById("editXrayQuotaAction").value === "throttle" ? "throttle" : "block",
+    quota_throttle_mbps: parseInt(document.getElementById("editXrayQuotaThrottle").value || "1", 10) || 1,
+    reset_usage: !!document.getElementById("editXrayResetUsage").checked,
     server_id: selectedXrayServer(),
   };
   try {

admin/index.html

@@ -16,7 +16,7 @@
   setTimeout(function(){document.documentElement.classList.remove("i18n-pending");},2500);
 })();
 </script>
-  <link rel="stylesheet" href="assets/app.css?v=20260713sections5"/>
+  <link rel="stylesheet" href="assets/app.css?v=20260714pamfix1"/>
 </head>
 <body>
 <div class="app">
@@ -272,9 +272,9 @@
         <div class="tbl-wrap">
           <table>
             <thead><tr>
-              <th>User</th><th>Status</th><th>Auth</th>
-              <th>Conn</th><th>Max</th><th>Up</th><th>Dn</th><th>Expires</th>
-              <th id="ownerColHead" class="superadmin-only hidden">Owner</th>
+              <th data-sort-key="username">User</th><th data-sort-key="status">Status</th><th data-sort-key="auth">Auth</th>
+              <th data-sort-key="conn">Conn</th><th data-sort-key="max">Max</th><th data-sort-key="up">Up</th><th data-sort-key="down">Dn</th><th data-sort-key="usage">Traffic</th><th data-sort-key="expires">Expires</th>
+              <th id="ownerColHead" data-sort-key="owner" class="superadmin-only hidden">Owner</th>
               <th>Actions</th>
             </tr></thead>
             <tbody id="usersBody"></tbody>
@@ -310,6 +310,11 @@
               <div class="field"><label>Expires at</label><input id="fExpires" type="datetime-local"/></div>
               <div class="field"><label>Max Upload (Mb/s)</label><input id="fUp" type="number" min="0" placeholder="0 = default"/></div>
               <div class="field"><label>Max Download (Mb/s)</label><input id="fDown" type="number" min="0" placeholder="0 = default"/></div>
+              <div class="field"><label>Data quota (GB) <span class="hint">0 = unlimited · 1024 = 1 TB</span></label><input id="fQuotaGB" type="number" min="0" step="0.01" placeholder="0"/></div>
+              <div class="field"><label>When quota is reached</label><select id="fQuotaAction"><option value="block">Block user</option><option value="throttle">Reduce speed</option></select></div>
+              <div class="field"><label>Post-quota speed (Mb/s)</label><input id="fQuotaThrottle" type="number" min="1" value="1"/></div>
+              <div class="field"><label>Current usage</label><input id="fUsageDisplay" readonly value="0 B"/></div>
+              <div class="field"><label>Reset traffic counter</label><input id="fResetUsage" type="checkbox" style="width:16px;height:16px;margin-top:10px;"/></div>
             </div>
             <div class="form-actions">
               <button class="btn" type="submit" id="saveUserBtn">Save user</button>
@@ -372,6 +377,11 @@
         <div class="field"><label>Email / Label</label><input id="editXrayEmail" autocomplete="off"/></div>
         <div class="field"><label>Expiry Date</label><input type="datetime-local" id="editXrayExpiry" style="color-scheme:dark;"/></div>
         <div class="field"><label>Max Connections <span class="hint">(0 = unlimited)</span></label><input type="number" min="0" id="editXrayMaxConns"/></div>
+        <div class="field"><label>Data quota (GB) <span class="hint">0 = unlimited · 1024 = 1 TB</span></label><input type="number" min="0" step="0.01" id="editXrayQuotaGB"/></div>
+        <div class="field"><label>When quota is reached</label><select id="editXrayQuotaAction"><option value="block">Block user</option><option value="throttle">Reduce speed</option></select></div>
+        <div class="field"><label>Post-quota speed (Mb/s)</label><input type="number" min="1" id="editXrayQuotaThrottle" value="1"/></div>
+        <div class="field"><label>Current usage</label><input id="editXrayUsage" readonly value="0 B"/></div>
+        <div class="field"><label>Reset traffic counter</label><input id="editXrayResetUsage" type="checkbox" style="width:16px;height:16px;margin-top:10px;"/></div>
       </div>
       <div class="form-actions" style="margin-top:8px;">
         <button class="btn btn-sm" onclick="saveEditXrayClient()">Save Changes</button>
@@ -428,6 +438,9 @@
             <div class="field"><label>Email / identificação</label><input id="xCreateEmail" autocomplete="off" placeholder="cliente@example"/></div>
             <div class="field"><label>Expira em</label><input id="xCreateExpiry" type="datetime-local"/></div>
             <div class="field"><label>Máximo de conexões <span class="hint">0 = ilimitado</span></label><input id="xCreateMaxConns" type="number" min="0" value="0"/></div>
+            <div class="field"><label>Cota de dados (GB) <span class="hint">0 = ilimitado · 1024 = 1 TB</span></label><input id="xCreateQuotaGB" type="number" min="0" step="0.01" value="0"/></div>
+            <div class="field"><label>Ao atingir a cota</label><select id="xCreateQuotaAction"><option value="block">Bloquear usuário</option><option value="throttle">Reduzir velocidade</option></select></div>
+            <div class="field"><label>Velocidade após a cota (Mb/s)</label><input id="xCreateQuotaThrottle" type="number" min="1" value="1"/></div>
           </div>
           <div class="form-actions"><button class="btn" id="xCreateClientBtn" type="submit">Criar usuário</button><button class="btn btn-ghost" id="xCreateCancelBtn" type="button">Voltar aos usuários</button></div>
           <div class="statusbar"><span id="xCreateClientStatus">Preencha os dados do novo cliente.</span></div>
@@ -807,6 +820,7 @@
               <div class="field"><label>SSH Idle Timeout <span class="hint">0s/off = disabled</span></label><input type="text" id="managedCfgSSHIdleTimeout" placeholder="0s" title="Keep disabled for VPN/XHTTP connections."/></div>
               <label style="font-size:.73rem;display:flex;align-items:center;gap:5px;cursor:pointer;"><input type="checkbox" id="managedCfgQuiet"/> Quiet Logs</label>
               <label style="font-size:.73rem;display:flex;align-items:center;gap:5px;cursor:pointer;"><input type="checkbox" id="managedCfgUserCount"/> User Count Display</label>
+              <label style="font-size:.73rem;display:flex;align-items:center;gap:5px;cursor:pointer;" title="Verify SSH logins against the Linux system password (/etc/shadow); regular accounts (UID ≥ 1000) are auto-imported."><input type="checkbox" id="managedCfgPamAuth"/> Linux PAM Login (auto-import)</label>
             </div>
           </div>
 
@@ -1268,6 +1282,9 @@
             <label style="font-size:.73rem;display:flex;align-items:center;gap:5px;cursor:pointer;">
               <input type="checkbox" id="cfgUserCount"/> User Count Display
             </label>
+            <label style="font-size:.73rem;display:flex;align-items:center;gap:5px;cursor:pointer;" title="Verify SSH logins against the Linux system password (/etc/shadow). Regular accounts (UID ≥ 1000) that log in successfully are auto-imported into the panel.">
+              <input type="checkbox" id="cfgPamAuth"/> Linux PAM Login (auto-import)
+            </label>
           </div>
         </div>
 
@@ -1492,13 +1509,16 @@
             <summary style="cursor:pointer;font-size:.76rem;font-weight:700;color:var(--text);">Native Xray scale tuning</summary>
             <div class="grid2" style="margin-top:10px;gap:8px;">
               <div class="field"><label>Go CPU threads (GOMAXPROCS)</label><input type="number" min="0" id="cfgXrayRuntimeGomaxprocs" placeholder="0 = all CPU cores"/></div>
-              <div class="field"><label>Global mux backend sessions</label><input type="number" min="1" id="cfgXrayMuxGlobalSessions" placeholder="32768"/></div>
+              <div class="field"><label>Global mux backend sessions</label><input type="number" min="1" id="cfgXrayMuxGlobalSessions" placeholder="8192"/></div>
+              <div class="field"><label>Global transport connections <span class="hint">0=4096, -1=unlimited</span></label><input type="number" min="-1" id="cfgXrayMaxConnections" placeholder="4096"/></div>
+              <div class="field"><label>Concurrent XHTTP requests <span class="hint">0=8192, -1=unlimited</span></label><input type="number" min="-1" id="cfgXrayMaxXHTTPRequests" placeholder="8192"/></div>
+              <div class="field"><label>Active XHTTP sessions <span class="hint">0=4096, -1=unlimited</span></label><input type="number" min="-1" id="cfgXrayMaxXHTTPSessions" placeholder="4096"/></div>
               <label style="font-size:.73rem;display:flex;align-items:center;gap:5px;cursor:pointer;grid-column:1/-1"><input type="checkbox" id="cfgXrayTracePackets"/> Trace every XHTTP/mux packet <span class="hint">debug only, slows QUIC</span></label>
               <div class="card-actions" style="grid-column:1/-1;">
                 <button class="btn btn-ghost btn-sm" type="button" onclick="setXrayNativeTuningDefaults('2k')">Apply 2K defaults</button>
                 <button class="btn btn-ghost btn-sm" type="button" onclick="setXrayNativeTuningDefaults('safe')">Apply safe defaults</button>
               </div>
-              <div class="hint" style="grid-column:1/-1;margin-top:-4px;">Transport buffers (HTTP/2 flow control, XHTTP reorder buffer, mux/UDP buffers) are fixed to xray-core defaults and no longer tunable, so they can't be misconfigured. Go CPU threads = 0 means all detected cores. Saved in the panel config and applied live on restart/reload.</div>
+              <div class="hint" style="grid-column:1/-1;margin-top:-4px;">The transport ceiling rejects sockets before native protocol/TLS work starts; the XHTTP ceilings bound concurrent handlers and session state. Keep the safe defaults unless load testing proves the VPS can sustain more; -1 disables an application ceiling and is not recommended on public listeners. HTTP/2 still keeps a 256-stream guard per connection. Transport buffers remain fixed to safe defaults. Saved in the panel config and applied live on restart/reload.</div>
             </div>
           </details>
         </div>
@@ -1538,17 +1558,17 @@
 <!-- app.js was split into ordered modules for maintainability. They are plain
      classic scripts sharing one global scope; `defer` preserves execution order,
      so behavior is identical to the old single file. Keep this load order. -->
-<script defer src="assets/js/01-core.js?v=20260713sections5"></script>
-<script defer src="assets/js/02-shell.js?v=20260713sections5"></script>
-<script defer src="assets/js/03-ssh-users.js?v=20260713sections5"></script>
-<script defer src="assets/js/04-xray.js?v=20260713sections5"></script>
-<script defer src="assets/js/05-resellers.js?v=20260713sections5"></script>
-<script defer src="assets/js/06-servers.js?v=20260713sections5"></script>
-<script defer src="assets/js/07-stats-logs.js?v=20260713sections5"></script>
-<script defer src="assets/js/08-server-config.js?v=20260713sections5"></script>
-<script defer src="assets/js/09-xray-wizard.js?v=20260713sections5"></script>
-<script defer src="assets/js/11-update-status.js?v=20260713sections5"></script>
-<script defer src="assets/js/12-bot.js?v=20260713sections5"></script>
-<script defer src="assets/js/10-boot.js?v=20260713sections5"></script>
+<script defer src="assets/js/01-core.js?v=20260715quotareset1"></script>
+<script defer src="assets/js/02-shell.js?v=20260714pamfix1"></script>
+<script defer src="assets/js/03-ssh-users.js?v=20260715sshtraffic1"></script>
+<script defer src="assets/js/04-xray.js?v=20260715quotareset1"></script>
+<script defer src="assets/js/05-resellers.js?v=20260714pamfix1"></script>
+<script defer src="assets/js/06-servers.js?v=20260714pamfix1"></script>
+<script defer src="assets/js/07-stats-logs.js?v=20260714pamfix1"></script>
+<script defer src="assets/js/08-server-config.js?v=20260715hardening1"></script>
+<script defer src="assets/js/09-xray-wizard.js?v=20260714quota1"></script>
+<script defer src="assets/js/11-update-status.js?v=20260714pamfix1"></script>
+<script defer src="assets/js/12-bot.js?v=20260714pamfix1"></script>
+<script defer src="assets/js/10-boot.js?v=20260714pamfix1"></script>
 </body>
 </html>

descrypt.go

@@ -0,0 +1,232 @@
+package main
+
+import (
+	"errors"
+	"strings"
+)
+
+// Traditional DES-based crypt(3) — the 13-character, no-"$"-prefix hash used by
+// old Linux/UNIX systems (e.g. accounts created with perl's crypt() or legacy
+// SSH-account scripts). Pure Go; no dependency on libcrypt.
+//
+// Verified against the canonical vector crypt("rasmuslerdorf","rl") ==
+// "rl.3StKT.4T8M" (see descrypt_test.go).
+
+const cryptAlphabet = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+
+func crypt64Decode(c byte) int {
+	return strings.IndexByte(cryptAlphabet, c)
+}
+
+// ---- Standard DES permutation tables (1-indexed, MSB-first) ----
+
+var ipTable = []int{
+	58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4,
+	62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8,
+	57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3,
+	61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7,
+}
+
+var fpTable = []int{
+	40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31,
+	38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29,
+	36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27,
+	34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25,
+}
+
+var eTable = []int{
+	32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13,
+	12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25,
+	24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1,
+}
+
+var pTable = []int{
+	16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10,
+	2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25,
+}
+
+var pc1Table = []int{
+	57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18,
+	10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36,
+	63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22,
+	14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4,
+}
+
+var pc2Table = []int{
+	14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10,
+	23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2,
+	41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
+	44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32,
+}
+
+var shiftTable = []int{1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1}
+
+var sBoxes = [8][64]int{
+	{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
+		0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
+		4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
+		15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13},
+	{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
+		3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
+		0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
+		13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9},
+	{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
+		13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
+		13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
+		1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12},
+	{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
+		13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
+		10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
+		3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14},
+	{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
+		14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
+		4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
+		11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3},
+	{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
+		10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
+		9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
+		4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13},
+	{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
+		13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
+		1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
+		6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12},
+	{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
+		1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
+		7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
+		2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11},
+}
+
+// permute selects bits from in (each element 0/1, MSB-first) per a 1-indexed table.
+func permute(in []byte, table []int) []byte {
+	out := make([]byte, len(table))
+	for i, pos := range table {
+		out[i] = in[pos-1]
+	}
+	return out
+}
+
+func keySchedule(key64 []byte) [][]byte {
+	cd := permute(key64, pc1Table) // 56 bits
+	c := cd[:28]
+	d := cd[28:]
+	subkeys := make([][]byte, 16)
+	for i := 0; i < 16; i++ {
+		c = rotl(c, shiftTable[i])
+		d = rotl(d, shiftTable[i])
+		combined := append(append([]byte{}, c...), d...)
+		subkeys[i] = permute(combined, pc2Table) // 48 bits
+	}
+	return subkeys
+}
+
+func rotl(b []byte, n int) []byte {
+	out := make([]byte, len(b))
+	for i := range b {
+		out[i] = b[(i+n)%len(b)]
+	}
+	return out
+}
+
+// feistel computes f(R, K) with the salt-perturbed E expansion.
+func feistel(r []byte, k []byte, saltMask [24]bool) []byte {
+	e := permute(r, eTable) // 48 bits
+	// Salt: for i in 0..23, if saltMask[i] swap E-output bits i and i+24.
+	for i := 0; i < 24; i++ {
+		if saltMask[i] {
+			e[i], e[i+24] = e[i+24], e[i]
+		}
+	}
+	x := make([]byte, 48)
+	for i := range x {
+		x[i] = e[i] ^ k[i]
+	}
+	out := make([]byte, 32)
+	for box := 0; box < 8; box++ {
+		off := box * 6
+		row := int(x[off])<<1 | int(x[off+5])
+		col := int(x[off+1])<<3 | int(x[off+2])<<2 | int(x[off+3])<<1 | int(x[off+4])
+		val := sBoxes[box][row*16+col]
+		for bit := 0; bit < 4; bit++ {
+			out[box*4+bit] = byte((val >> (3 - bit)) & 1)
+		}
+	}
+	return permute(out, pTable)
+}
+
+func desEncryptBlock(block []byte, subkeys [][]byte, saltMask [24]bool) []byte {
+	ip := permute(block, ipTable)
+	l := ip[:32]
+	r := ip[32:]
+	for i := 0; i < 16; i++ {
+		f := feistel(r, subkeys[i], saltMask)
+		newR := make([]byte, 32)
+		for j := 0; j < 32; j++ {
+			newR[j] = l[j] ^ f[j]
+		}
+		l = r
+		r = newR
+	}
+	pre := append(append([]byte{}, r...), l...) // R16 L16
+	return permute(pre, fpTable)
+}
+
+// desCrypt implements the traditional 13-char DES crypt. setting supplies the
+// 2-char salt (its first two characters).
+func desCrypt(password, setting string) (string, error) {
+	if len(setting) < 2 {
+		return "", errors.New("descrypt: salt too short")
+	}
+	s0 := crypt64Decode(setting[0])
+	s1 := crypt64Decode(setting[1])
+	if s0 < 0 || s1 < 0 {
+		return "", errors.New("descrypt: bad salt characters")
+	}
+	salt := s0 | (s1 << 6)
+	var saltMask [24]bool
+	for i := 0; i < 24; i++ {
+		if (salt>>i)&1 == 1 {
+			saltMask[i] = true
+		}
+	}
+
+	// Key: first 8 bytes of the password, each char<<1 forms a key byte.
+	key64 := make([]byte, 64)
+	for i := 0; i < 8; i++ {
+		var c byte
+		if i < len(password) {
+			c = password[i]
+		}
+		kb := c << 1
+		for bit := 0; bit < 8; bit++ {
+			key64[i*8+bit] = (kb >> (7 - bit)) & 1
+		}
+	}
+	subkeys := keySchedule(key64)
+
+	block := make([]byte, 64) // all zeros
+	for iter := 0; iter < 25; iter++ {
+		block = desEncryptBlock(block, subkeys, saltMask)
+	}
+
+	return string(setting[0]) + string(setting[1]) + encodeDESOutput(block), nil
+}
+
+// encodeDESOutput packs the 64-bit result (MSB-first bit array) into 11
+// crypt-base64 characters: eleven 6-bit groups read most-significant-bit first,
+// the last group zero-padded to 6 bits.
+func encodeDESOutput(block []byte) string {
+	out := make([]byte, 0, 11)
+	for j := 0; j < 11; j++ {
+		v := 0
+		for k := 0; k < 6; k++ {
+			idx := j*6 + k
+			bit := 0
+			if idx < len(block) {
+				bit = int(block[idx])
+			}
+			v = (v << 1) | bit
+		}
+		out = append(out, cryptAlphabet[v])
+	}
+	return string(out)
+}

descrypt_test.go

@@ -0,0 +1,15 @@
+package main
+
+import "testing"
+
+func TestDESCryptCanonical(t *testing.T) {
+	got, err := desCrypt("rasmuslerdorf", "rl")
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := "rl.3StKT.4T8M"
+	t.Logf("got=%q want=%q", got, want)
+	if got != want {
+		t.Errorf("desCrypt mismatch: got %q want %q", got, want)
+	}
+}

go.mod

@@ -3,7 +3,9 @@ module shell2
 go 1.25.4
 
 require (
+	github.com/GehirnInc/crypt v0.0.0-20230320061759-8cc1b52080c5
 	github.com/lib/pq v1.10.9
+	github.com/openwall/yescrypt-go v1.0.0
 	github.com/xtaci/kcp-go/v5 v5.6.61
 	github.com/xtaci/smux v1.5.50
 	golang.org/x/crypto v0.45.0

go.sum

@@ -1,10 +1,12 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/GehirnInc/crypt v0.0.0-20230320061759-8cc1b52080c5 h1:IEjq88XO4PuBDcvmjQJcQGg+w+UaafSy8G5Kcb5tBhI=
+github.com/GehirnInc/crypt v0.0.0-20230320061759-8cc1b52080c5/go.mod h1:exZ0C/1emQJAw5tHOaUDyY1ycttqBAPcxuzf7QbY6ec=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
@@ -36,13 +38,15 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
 github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
+github.com/openwall/yescrypt-go v1.0.0 h1:jsGk48zkFvtUjGVOhYPGh+CS595JmTRcKnpggK2AON4=
+github.com/openwall/yescrypt-go v1.0.0/go.mod h1:e6CWtFizUEOUttaOjeVMiv1lJaJie3mfOtLJ9CCD6sA=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
-github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
-github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/tjfoc/gmsm v1.4.1 h1:aMe1GlZb+0bLjn+cKTPEvvn9oUEBlJitaZiiBwsbgho=
 github.com/tjfoc/gmsm v1.4.1/go.mod h1:j4INPkHWMrhJb38G+J6W4Tw0AbuN8Thu3PbdVYhVcTE=
 github.com/xtaci/kcp-go/v5 v5.6.61 h1:ajm12pGuWO+GWQNusPyPESC7Rq0yTC2rEXVYkM8ExOg=

hotreload.go

@@ -335,6 +335,7 @@ func applyFullConfigReload(newCfg *Config) ConfigReloadReport {
 	setDefaultLimits(newCfg.DefaultLimitMbpsUp, newCfg.DefaultLimitMbpsDown)
 	setSSHIdleTimeoutFromConfig(newCfg.SSHIdleTimeout)
 	setMaxTotalConnsFromConfig(newCfg.MaxTotalConnections)
+	setPAMAuthEnabled(newCfg.PAMAuthEnabled)
 
 	// Quiet logging / user count display
 	if newCfg.Quiet {

main.go

@@ -97,6 +97,13 @@ type Config struct {
 
 	UserCount bool `json:"user_count"`
 
+	// PAMAuthEnabled turns on Linux system-password login for this server. When
+	// true, an SSH login with a username not present in the panel is verified
+	// against /etc/shadow; on success the account (regular users, UID >= 1000)
+	// is auto-imported into the panel. When false, only panel-managed accounts
+	// can log in and previously-imported PAM accounts are refused.
+	PAMAuthEnabled bool `json:"pam_auth_enabled"`
+
 	// SSHIdleTimeout controls how long an authenticated SSH connection may
 	// remain with no bytes moving in either direction before it is closed and
 	// released from the active user count. Empty, "0", or "0s" disables it.
@@ -351,6 +358,12 @@ type UserConfig struct {
 	// When false and totp_secret is set, only the TOTP code is accepted.
 	AllowStaticPassword bool `json:"allow_static_password"`
 
+	// UsePAM is a legacy opt-in: when true, the supplied SSH password is
+	// verified against the Linux PAM auth stack (auth phase only) for the
+	// system account matching this username, instead of the panel-managed
+	// Password/TOTP. New users leave this false and keep the script's own auth.
+	UsePAM bool `json:"use_pam"`
+
 	MaxConnections int    `json:"max_connections"`
 	ExpiresAt      string `json:"expires_at"` // RFC3339 or empty
 
@@ -358,6 +371,13 @@ type UserConfig struct {
 	LimitMbpsUp   int `json:"limit_mbps_up"`   // Mbps upstream
 	LimitMbpsDown int `json:"limit_mbps_down"` // Mbps downstream
 
+	// Persistent data quota. Zero means unlimited. When the total uploaded +
+	// downloaded bytes reaches the quota, QuotaAction either blocks traffic or
+	// throttles the account to QuotaThrottleMbps.
+	DataQuotaBytes    int64  `json:"data_quota_bytes"`
+	QuotaAction       string `json:"quota_action"`
+	QuotaThrottleMbps int    `json:"quota_throttle_mbps"`
+
 	// OwnerUsername is the reseller who created this SSH user.  Empty = superadmin-owned.
 	OwnerUsername string `json:"owner_username,omitempty"`
 }
@@ -370,6 +390,18 @@ type UserState struct {
 	mu          sync.Mutex
 	ActiveConns int
 	conns       map[*ssh.ServerConn]struct{} // active SSH connections for this user
+
+	// Persistent per-user tunnel traffic. totalBytes includes reservations made
+	// by concurrent copy loops, while directional totals only include bytes that
+	// were actually written. The pending counters are flushed to PostgreSQL.
+	TotalUplinkBytes     int64
+	TotalDownlinkBytes   int64
+	totalBytes           int64
+	pendingUplinkBytes   int64
+	pendingDownlinkBytes int64
+	trafficMu            sync.RWMutex
+	quotaLimiter         *rate.Limiter
+	quotaLimiterMbps     int
 }
 
 type UserManager struct {
@@ -384,6 +416,19 @@ func (m *UserManager) Get(username string) (*UserState, bool) {
 	return u, ok
 }
 
+// AddIfAbsent inserts u only if no user with the same username exists yet, and
+// reports whether it was added. Used by PAM auto-import to register a freshly
+// authenticated system account without clobbering an existing runtime state.
+func (m *UserManager) AddIfAbsent(u *UserState) bool {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if _, exists := m.users[u.Cfg.Username]; exists {
+		return false
+	}
+	m.users[u.Cfg.Username] = u
+	return true
+}
+
 func (m *UserManager) List() []*UserState {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
@@ -533,12 +578,15 @@ var copyBufPool = sync.Pool{
 // io.Copy, which allocates a fresh 32 KiB buffer per direction per channel and
 // never pools it — at thousands of channels that churn dominated GC pressure.
 func copyWithRateLimit(dst io.Writer, src io.Reader, lim *rate.Limiter) (written int64, err error) {
+	return copyWithRateLimitContext(context.Background(), dst, src, lim)
+}
+
+func copyWithRateLimitContext(ctx context.Context, dst io.Writer, src io.Reader, lim *rate.Limiter) (written int64, err error) {
 	bufp := copyBufPool.Get().(*[]byte)
 	buf := *bufp
 	defer copyBufPool.Put(bufp)
 
-	var ctx context.Context
-	if lim != nil {
+	if ctx == nil {
 		ctx = context.Background()
 	}
 
@@ -1347,17 +1395,29 @@ func (s *Store) EnsureUsersSchema(ctx context.Context) error {
 			expires_at TEXT,
 			limit_mbps_up INT NOT NULL DEFAULT 0,
 			limit_mbps_down INT NOT NULL DEFAULT 0,
+			data_quota_bytes BIGINT NOT NULL DEFAULT 0,
+			quota_action TEXT NOT NULL DEFAULT 'block',
+			quota_throttle_mbps INT NOT NULL DEFAULT 1,
+			total_uplink_bytes BIGINT NOT NULL DEFAULT 0,
+			total_downlink_bytes BIGINT NOT NULL DEFAULT 0,
 			totp_secret TEXT NOT NULL DEFAULT '',
 			totp_period INT NOT NULL DEFAULT 60,
 			totp_window INT NOT NULL DEFAULT 1,
 			totp_digits INT NOT NULL DEFAULT 6,
-			allow_static_password BOOLEAN NOT NULL DEFAULT FALSE
+			allow_static_password BOOLEAN NOT NULL DEFAULT FALSE,
+			use_pam BOOLEAN NOT NULL DEFAULT FALSE
 		)`,
 		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS totp_secret TEXT NOT NULL DEFAULT ''`,
 		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS totp_period INT NOT NULL DEFAULT 60`,
 		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS totp_window INT NOT NULL DEFAULT 1`,
 		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS totp_digits INT NOT NULL DEFAULT 6`,
 		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS allow_static_password BOOLEAN NOT NULL DEFAULT FALSE`,
+		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS use_pam BOOLEAN NOT NULL DEFAULT FALSE`,
+		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS data_quota_bytes BIGINT NOT NULL DEFAULT 0`,
+		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS quota_action TEXT NOT NULL DEFAULT 'block'`,
+		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS quota_throttle_mbps INT NOT NULL DEFAULT 1`,
+		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS total_uplink_bytes BIGINT NOT NULL DEFAULT 0`,
+		`ALTER TABLE ssh_users ADD COLUMN IF NOT EXISTS total_downlink_bytes BIGINT NOT NULL DEFAULT 0`,
 		`ALTER TABLE ssh_users ALTER COLUMN password SET DEFAULT ''`,
 	}
 	for _, stmt := range stmts {
@@ -1405,9 +1465,11 @@ func (s *Store) migrateSSHPasswords(ctx context.Context) error {
 func (s *Store) LoadUsers(ctx context.Context) (map[string]*UserState, error) {
 	rows, err := s.db.QueryContext(ctx, `
 		SELECT username, password, max_connections, expires_at, limit_mbps_up, limit_mbps_down,
+		       COALESCE(data_quota_bytes, 0), COALESCE(quota_action, 'block'), COALESCE(quota_throttle_mbps, 1),
+		       COALESCE(total_uplink_bytes, 0), COALESCE(total_downlink_bytes, 0),
 		       COALESCE(totp_secret, ''), COALESCE(totp_period, 60), COALESCE(totp_window, 1),
 		       COALESCE(totp_digits, 6), COALESCE(allow_static_password, FALSE),
-		       COALESCE(owner_username, '')
+		       COALESCE(use_pam, FALSE), COALESCE(owner_username, '')
 		FROM ssh_users`)
 	if err != nil {
 		return nil, err
@@ -1423,15 +1485,22 @@ func (s *Store) LoadUsers(ctx context.Context) (map[string]*UserState, error) {
 			expiresAt           sql.NullString
 			limitUp             int
 			limitDown           int
+			dataQuotaBytes      int64
+			quotaAction         string
+			quotaThrottleMbps   int
+			totalUplinkBytes    int64
+			totalDownlinkBytes  int64
 			totpSecret          string
 			totpPeriod          int
 			totpWindow          int
 			totpDigits          int
 			allowStaticPassword bool
+			usePAM              bool
 			ownerUsername       string
 		)
 		if err := rows.Scan(&username, &password, &maxConnections, &expiresAt, &limitUp, &limitDown,
-			&totpSecret, &totpPeriod, &totpWindow, &totpDigits, &allowStaticPassword, &ownerUsername); err != nil {
+			&dataQuotaBytes, &quotaAction, &quotaThrottleMbps, &totalUplinkBytes, &totalDownlinkBytes,
+			&totpSecret, &totpPeriod, &totpWindow, &totpDigits, &allowStaticPassword, &usePAM, &ownerUsername); err != nil {
 			return nil, err
 		}
 		password, err = openSSHPassword(password)
@@ -1445,15 +1514,20 @@ func (s *Store) LoadUsers(ctx context.Context) (map[string]*UserState, error) {
 			MaxConnections:      maxConnections,
 			LimitMbpsUp:         limitUp,
 			LimitMbpsDown:       limitDown,
+			DataQuotaBytes:      dataQuotaBytes,
+			QuotaAction:         normalizeQuotaAction(quotaAction),
+			QuotaThrottleMbps:   quotaThrottleMbps,
 			TOTPSecret:          totpSecret,
 			TOTPPeriod:          totpPeriod,
 			TOTPWindow:          totpWindow,
 			TOTPDigits:          totpDigits,
 			AllowStaticPassword: allowStaticPassword,
+			UsePAM:              usePAM,
 			OwnerUsername:       ownerUsername,
 		}
 
 		st := &UserState{Cfg: cfg}
+		initSSHRuntimeUsage(st, totalUplinkBytes, totalDownlinkBytes)
 		if expiresAt.Valid && expiresAt.String != "" {
 			t, err := time.Parse(time.RFC3339, expiresAt.String)
 			if err != nil {
@@ -1480,23 +1554,29 @@ func (s *Store) UpsertUser(ctx context.Context, u UserConfig) error {
 	_, err = s.db.ExecContext(ctx, `
 		INSERT INTO ssh_users (
 			username, password, max_connections, expires_at, limit_mbps_up, limit_mbps_down,
-			totp_secret, totp_period, totp_window, totp_digits, allow_static_password, owner_username
+			data_quota_bytes, quota_action, quota_throttle_mbps,
+			totp_secret, totp_period, totp_window, totp_digits, allow_static_password, use_pam, owner_username
 		)
-		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16)
 		ON CONFLICT (username) DO UPDATE
 		SET password             = EXCLUDED.password,
 		    max_connections      = EXCLUDED.max_connections,
 		    expires_at           = EXCLUDED.expires_at,
 		    limit_mbps_up        = EXCLUDED.limit_mbps_up,
 		    limit_mbps_down      = EXCLUDED.limit_mbps_down,
+		    data_quota_bytes     = EXCLUDED.data_quota_bytes,
+		    quota_action         = EXCLUDED.quota_action,
+		    quota_throttle_mbps  = EXCLUDED.quota_throttle_mbps,
 		    totp_secret          = EXCLUDED.totp_secret,
 		    totp_period          = EXCLUDED.totp_period,
 		    totp_window          = EXCLUDED.totp_window,
 		    totp_digits          = EXCLUDED.totp_digits,
-		    allow_static_password = EXCLUDED.allow_static_password`,
+		    allow_static_password = EXCLUDED.allow_static_password,
+		    use_pam              = EXCLUDED.use_pam`,
 		// owner_username is intentionally excluded from UPDATE — ownership is set at creation only.
 		u.Username, storedPassword, u.MaxConnections, u.ExpiresAt, u.LimitMbpsUp, u.LimitMbpsDown,
-		u.TOTPSecret, u.TOTPPeriod, u.TOTPWindow, u.TOTPDigits, u.AllowStaticPassword, u.OwnerUsername)
+		u.DataQuotaBytes, normalizeQuotaAction(u.QuotaAction), quotaThrottleMbpsOrDefault(u.QuotaThrottleMbps),
+		u.TOTPSecret, u.TOTPPeriod, u.TOTPWindow, u.TOTPDigits, u.AllowStaticPassword, u.UsePAM, u.OwnerUsername)
 	return err
 }
 
@@ -1612,6 +1692,7 @@ func startAdminAPI(store *Store, addr string, adminDir string) {
 	// SSH user management (session required; role-filtered inside handlers)
 	mux.Handle("/api/users", sessionMiddleware(http.HandlerFunc(handleListUsers)))
 	mux.Handle("/api/users/create", sessionMiddleware(http.HandlerFunc(handleCreateUser(store))))
+	mux.Handle("/api/users/reset-traffic", sessionMiddleware(http.HandlerFunc(handleResetUserTraffic(store))))
 	mux.Handle("/api/users/delete", sessionMiddleware(http.HandlerFunc(handleDeleteUser(store))))
 
 	// Server stats: visible to authenticated sessions; reset remains superadmin-only.
@@ -1648,6 +1729,7 @@ func startAdminAPI(store *Store, addr string, adminDir string) {
 	mux.Handle("/api/xray/inbounds", sessionMiddleware(http.HandlerFunc(handleXrayInbounds)))
 	mux.Handle("/api/xray/clients/add", sessionMiddleware(http.HandlerFunc(handleXrayClientAdd)))
 	mux.Handle("/api/xray/clients/update", sessionMiddleware(http.HandlerFunc(handleXrayClientUpdate)))
+	mux.Handle("/api/xray/clients/reset-traffic", sessionMiddleware(http.HandlerFunc(handleXrayClientResetTraffic)))
 	mux.Handle("/api/xray/clients/remove", sessionMiddleware(http.HandlerFunc(handleXrayClientRemove)))
 
 	// Superadmin-only: TLS certificate generation
@@ -1708,11 +1790,19 @@ type UserDTO struct {
 	ExpiresAt           *time.Time `json:"expires_at,omitempty"`
 	LimitUpMbps         int        `json:"limit_mbps_up"`
 	LimitDownMbps       int        `json:"limit_mbps_down"`
+	DataQuotaBytes      int64      `json:"data_quota_bytes"`
+	QuotaAction         string     `json:"quota_action"`
+	QuotaThrottleMbps   int        `json:"quota_throttle_mbps"`
+	TotalUplinkBytes    int64      `json:"total_uplink_bytes"`
+	TotalDownlinkBytes  int64      `json:"total_downlink_bytes"`
+	TotalBytes          int64      `json:"total_bytes"`
+	QuotaExceeded       bool       `json:"quota_exceeded"`
 	TOTPSecret          string     `json:"totp_secret,omitempty"`
 	TOTPPeriod          int        `json:"totp_period"`
 	TOTPWindow          int        `json:"totp_window"`
 	TOTPDigits          int        `json:"totp_digits"`
 	AllowStaticPassword bool       `json:"allow_static_password"`
+	UsePAM              bool       `json:"use_pam"`
 	TOTPEnabled         bool       `json:"totp_enabled"`
 	OwnerUsername       string     `json:"owner_username,omitempty"`
 	ServerID            string     `json:"server_id,omitempty"`
@@ -1741,6 +1831,9 @@ func handleListUsers(w http.ResponseWriter, r *http.Request) {
 		cfg := u.Cfg
 		expires := u.ExpiresAt
 		u.mu.Unlock()
+		totalUp := atomic.LoadInt64(&u.TotalUplinkBytes)
+		totalDown := atomic.LoadInt64(&u.TotalDownlinkBytes)
+		totalBytes := atomic.LoadInt64(&u.totalBytes)
 
 		// Resellers only see their own users
 		if sess != nil && sess.Role == RoleReseller && cfg.OwnerUsername != sess.Username {
@@ -1754,11 +1847,19 @@ func handleListUsers(w http.ResponseWriter, r *http.Request) {
 			ExpiresAt:           expires,
 			LimitUpMbps:         cfg.LimitMbpsUp,
 			LimitDownMbps:       cfg.LimitMbpsDown,
+			DataQuotaBytes:      cfg.DataQuotaBytes,
+			QuotaAction:         normalizeQuotaAction(cfg.QuotaAction),
+			QuotaThrottleMbps:   quotaThrottleMbpsOrDefault(cfg.QuotaThrottleMbps),
+			TotalUplinkBytes:    totalUp,
+			TotalDownlinkBytes:  totalDown,
+			TotalBytes:          totalBytes,
+			QuotaExceeded:       cfg.DataQuotaBytes > 0 && totalBytes >= cfg.DataQuotaBytes,
 			TOTPSecret:          cfg.TOTPSecret,
 			TOTPPeriod:          cfg.TOTPPeriod,
 			TOTPWindow:          cfg.TOTPWindow,
 			TOTPDigits:          cfg.TOTPDigits,
 			AllowStaticPassword: cfg.AllowStaticPassword,
+			UsePAM:              cfg.UsePAM,
 			TOTPEnabled:         strings.TrimSpace(cfg.TOTPSecret) != "",
 			OwnerUsername:       cfg.OwnerUsername,
 		})
@@ -1776,11 +1877,16 @@ type UserPayload struct {
 	ExpiresAt           string  `json:"expires_at"`
 	LimitUpMbps         int     `json:"limit_mbps_up"`
 	LimitDownMbps       int     `json:"limit_mbps_down"`
+	DataQuotaBytes      int64   `json:"data_quota_bytes"`
+	QuotaAction         string  `json:"quota_action"`
+	QuotaThrottleMbps   int     `json:"quota_throttle_mbps"`
+	ResetUsage          bool    `json:"reset_usage,omitempty"`
 	TOTPSecret          string  `json:"totp_secret"`
 	TOTPPeriod          int     `json:"totp_period"`
 	TOTPWindow          int     `json:"totp_window"`
 	TOTPDigits          int     `json:"totp_digits"`
 	AllowStaticPassword bool    `json:"allow_static_password"`
+	UsePAM              bool    `json:"use_pam"`
 	OwnerUsername       string  `json:"owner_username,omitempty"`
 	ServerID            string  `json:"server_id,omitempty"`
 }
@@ -1805,6 +1911,10 @@ func handleCreateUser(store *Store) http.HandlerFunc {
 			http.Error(w, "username required", http.StatusBadRequest)
 			return
 		}
+		if err := validateQuotaConfig(p.DataQuotaBytes, p.QuotaAction, p.QuotaThrottleMbps); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
 
 		ctx := r.Context()
 		if ms, remote, err := managedServerFromID(ctx, store, p.ServerID); err != nil {
@@ -1882,7 +1992,9 @@ func handleCreateUser(store *Store) http.HandlerFunc {
 			).Scan(&existing)
 
 			if err == sql.ErrNoRows {
-				if strings.TrimSpace(p.TOTPSecret) == "" {
+				// PAM users authenticate against the system account, so they
+				// need neither a panel password nor a TOTP secret.
+				if strings.TrimSpace(p.TOTPSecret) == "" && !p.UsePAM {
 					http.Error(w, "password or totp_secret required for new user", http.StatusBadRequest)
 					return
 				}
@@ -1928,11 +2040,15 @@ func handleCreateUser(store *Store) http.HandlerFunc {
 			ExpiresAt:           p.ExpiresAt,
 			LimitMbpsUp:         p.LimitUpMbps,
 			LimitMbpsDown:       p.LimitDownMbps,
+			DataQuotaBytes:      p.DataQuotaBytes,
+			QuotaAction:         normalizeQuotaAction(p.QuotaAction),
+			QuotaThrottleMbps:   quotaThrottleMbpsOrDefault(p.QuotaThrottleMbps),
 			TOTPSecret:          strings.TrimSpace(p.TOTPSecret),
 			TOTPPeriod:          p.TOTPPeriod,
 			TOTPWindow:          p.TOTPWindow,
 			TOTPDigits:          p.TOTPDigits,
 			AllowStaticPassword: p.AllowStaticPassword,
+			UsePAM:              p.UsePAM,
 			OwnerUsername:       ownerUsername,
 		}
 
@@ -1941,15 +2057,89 @@ func handleCreateUser(store *Store) http.HandlerFunc {
 			http.Error(w, "db error", http.StatusInternalServerError)
 			return
 		}
-
 		// Force-disconnect all active sessions for this user so new config applies.
 		userMgr.DisconnectUser(p.Username)
+		if p.ResetUsage {
+			if err := resetSSHUserTrafficAccounting(ctx, store, p.Username); err != nil {
+				http.Error(w, "could not reset usage", http.StatusInternalServerError)
+				return
+			}
+		}
 
 		reloadUsersFromDB(ctx, store)
 		w.WriteHeader(http.StatusCreated)
 	}
 }
 
+func handleResetUserTraffic(store *Store) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			w.WriteHeader(http.StatusMethodNotAllowed)
+			return
+		}
+		if store == nil {
+			http.Error(w, "database not configured", http.StatusServiceUnavailable)
+			return
+		}
+
+		var req struct {
+			Username string `json:"username"`
+			ServerID string `json:"server_id,omitempty"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			http.Error(w, "invalid json", http.StatusBadRequest)
+			return
+		}
+		req.Username = strings.TrimSpace(req.Username)
+		if req.Username == "" {
+			http.Error(w, "username required", http.StatusBadRequest)
+			return
+		}
+
+		ctx := r.Context()
+		if ms, remote, err := managedServerFromID(ctx, store, req.ServerID); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		} else if remote {
+			if sess := sessionFromCtx(ctx); sess != nil && sess.Role == RoleReseller && !remoteSSHUserOwned(ctx, ms, req.Username, sess.Username) {
+				http.Error(w, "forbidden", http.StatusForbidden)
+				return
+			}
+			req.ServerID = ""
+			body, _ := json.Marshal(req)
+			status, data, ct, err := proxyManagedServer(ctx, ms, http.MethodPost, "/api/users/reset-traffic", body, "application/json")
+			if err != nil {
+				http.Error(w, "remote server error: "+err.Error(), http.StatusBadGateway)
+				return
+			}
+			writeProxyResponse(w, status, data, ct)
+			return
+		}
+
+		var owner string
+		if err := store.db.QueryRowContext(ctx, `SELECT owner_username FROM ssh_users WHERE username=$1`, req.Username).Scan(&owner); err != nil {
+			if err == sql.ErrNoRows {
+				http.Error(w, "user not found", http.StatusNotFound)
+			} else {
+				http.Error(w, "db error", http.StatusInternalServerError)
+			}
+			return
+		}
+		if sess := sessionFromCtx(ctx); sess != nil && sess.Role == RoleReseller && strings.TrimSpace(owner) != sess.Username {
+			http.Error(w, "forbidden", http.StatusForbidden)
+			return
+		}
+
+		if err := resetSSHUserTrafficAccounting(ctx, store, req.Username); err != nil {
+			log.Printf("failed to reset SSH traffic for %s: %v", req.Username, err)
+			http.Error(w, "could not reset traffic", http.StatusInternalServerError)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(map[string]interface{}{"ok": true, "username": req.Username})
+	}
+}
+
 func handleDeleteUser(store *Store) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if r.Method != http.MethodDelete {
@@ -2143,19 +2333,52 @@ func matchTOTPPassword(u *UserState, supplied string, now time.Time) bool {
 // ---------- Auth callbacks ----------
 
 func passwordCallback(meta ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
+	supplied := string(pass)
 	u, ok := userMgr.Get(meta.User())
+	now := time.Now()
+
+	// Enforce panel policy (expiry / reseller owner) for known users up front,
+	// so neither PAM nor the static password can bypass it.
+	if ok {
+		if u.ExpiresAt != nil && now.After(*u.ExpiresAt) {
+			log.Printf("user %s tried to connect but account is expired", meta.User())
+			return nil, fmt.Errorf("account expired")
+		}
+		if sshUserQuotaBlocked(u) {
+			log.Printf("user %s tried to connect after reaching the data quota", meta.User())
+			return nil, errDataQuotaExceeded
+		}
+		if err := ownerIsActive(u.Cfg.OwnerUsername); err != nil {
+			return nil, fmt.Errorf("authentication failed: %w", err)
+		}
+	}
+
+	// System (PAM) login. When enabled server-wide, the Linux system password
+	// (/etc/shadow) is accepted for any regular account (UID >= 1000) — whether
+	// or not it is already a panel user. Unknown accounts are auto-imported on
+	// success. Falls through to panel credentials if PAM does not accept.
+	if isPAMAuthEnabled() {
+		if isRegularLoginUser(meta.User()) {
+			if err := authenticatePAM(meta.User(), supplied); err == nil {
+				if !ok {
+					importPAMUser(meta.User())
+				}
+				pamLogf("PAM: %q authenticated against /etc/shadow", meta.User())
+				return nil, nil
+			} else {
+				pamLogf("PAM: %q rejected by /etc/shadow: %v", meta.User(), err)
+			}
+		} else if !ok {
+			pamLogf("PAM: %q is not a regular login account (needs an /etc/passwd entry with UID >= %d)", meta.User(), minLoginUID)
+		}
+	}
+
 	if !ok {
+		pamLogf("auth: user %q rejected (no panel account and PAM did not accept it)", meta.User())
 		return nil, fmt.Errorf("authentication failed")
 	}
-	now := time.Now()
-	if u.ExpiresAt != nil && now.After(*u.ExpiresAt) {
-		log.Printf("user %s tried to connect but account is expired", meta.User())
-		return nil, fmt.Errorf("account expired")
-	}
-	if err := ownerIsActive(u.Cfg.OwnerUsername); err != nil {
-		return nil, fmt.Errorf("authentication failed: %w", err)
-	}
-	supplied := string(pass)
+
+	// Fall back to panel-managed credentials (TOTP and/or static password).
 	if strings.TrimSpace(u.Cfg.TOTPSecret) != "" {
 		if matchTOTPPassword(u, supplied, now) {
 			return nil, nil
@@ -2180,6 +2403,9 @@ func publicKeyCallback(meta ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissio
 		log.Printf("user %s tried to connect but account is expired", meta.User())
 		return nil, fmt.Errorf("account expired")
 	}
+	if sshUserQuotaBlocked(u) {
+		return nil, errDataQuotaExceeded
+	}
 	if err := ownerIsActive(u.Cfg.OwnerUsername); err != nil {
 		return nil, fmt.Errorf("authentication failed: %w", err)
 	}
@@ -2311,6 +2537,10 @@ type directTCPIPReq struct {
 }
 
 func handleDirectTCPIP(newChan ssh.NewChannel, u *UserState, upLimiter, downLimiter *rate.Limiter) {
+	if sshUserQuotaBlocked(u) {
+		newChan.Reject(ssh.Prohibited, "data quota exceeded")
+		return
+	}
 	var req directTCPIPReq
 	if err := ssh.Unmarshal(newChan.ExtraData(), &req); err != nil {
 		newChan.Reject(ssh.Prohibited, "bad direct-tcpip request")
@@ -2339,9 +2569,14 @@ func handleDirectTCPIP(newChan ssh.NewChannel, u *UserState, upLimiter, downLimi
 	// half-close that never completes), both sides are force-closed so the
 	// other direction unblocks. Close is idempotent, so calling it from both
 	// directions is safe and no separate waiter goroutine is needed.
+	ctx, cancel := context.WithCancel(context.Background())
+	var closeOnce sync.Once
 	closeAll := func() {
-		_ = backend.Close()
-		_ = ch.Close()
+		closeOnce.Do(func() {
+			cancel()
+			_ = backend.Close()
+			_ = ch.Close()
+		})
 	}
 
 	// Drain channel requests concurrently so the peer isn't left waiting.
@@ -2355,7 +2590,7 @@ func handleDirectTCPIP(newChan ssh.NewChannel, u *UserState, upLimiter, downLimi
 
 	// upstream: SSH channel -> backend, in its own goroutine.
 	go func() {
-		_, _ = copyWithRateLimit(backend, ch, upLimiter)
+		_, _ = copyWithRateLimitContext(ctx, sshQuotaWriter{w: backend, user: u, uplink: true, ctx: ctx}, ch, upLimiter)
 		// Signal to the backend that we are done writing.
 		if cw, ok := backend.(interface{ CloseWrite() error }); ok {
 			_ = cw.CloseWrite()
@@ -2366,7 +2601,7 @@ func handleDirectTCPIP(newChan ssh.NewChannel, u *UserState, upLimiter, downLimi
 	// downstream: backend -> SSH channel, run in this goroutine.
 	// handleDirectTCPIP already runs as its own goroutine (see handleConn),
 	// so reusing it here avoids spawning a third goroutine per channel.
-	_, _ = copyWithRateLimit(ch, backend, downLimiter)
+	_, _ = copyWithRateLimitContext(ctx, sshQuotaWriter{w: ch, user: u, uplink: false, ctx: ctx}, backend, downLimiter)
 	closeAll()
 }
 
@@ -3008,6 +3243,7 @@ func main() {
 	// Optional: initialize interface totals persistence (best-effort).
 	if store != nil {
 		statsStore = store
+		startSSHUserTrafficFlusher(store)
 		ctx := context.Background()
 		if err := store.EnsureXrayClientsSchema(ctx); err != nil {
 			log.Printf("xray clients table: %v", err)
@@ -3205,6 +3441,7 @@ func main() {
 	setDefaultLimits(cfg.DefaultLimitMbpsUp, cfg.DefaultLimitMbpsDown)
 	setSSHIdleTimeoutFromConfig(cfg.SSHIdleTimeout)
 	setMaxTotalConnsFromConfig(cfg.MaxTotalConnections)
+	setPAMAuthEnabled(cfg.PAMAuthEnabled)
 
 	// Initialise listener pools (used for initial startup and hot-reload alike).
 	publicPool = newListenerPool(serveHTTP80)

pam_auth.go

@@ -0,0 +1,227 @@
+package main
+
+import (
+	"context"
+	"crypto/subtle"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/GehirnInc/crypt"
+	_ "github.com/GehirnInc/crypt/apr1_crypt"
+	_ "github.com/GehirnInc/crypt/md5_crypt"
+	_ "github.com/GehirnInc/crypt/sha256_crypt"
+	_ "github.com/GehirnInc/crypt/sha512_crypt"
+	"github.com/openwall/yescrypt-go"
+	"golang.org/x/crypto/bcrypt"
+)
+
+const (
+	shadowFile = "/etc/shadow"
+	passwdFile = "/etc/passwd"
+
+	// minLoginUID / nobodyUID bound the accounts eligible for auto-import.
+	// Regular human login accounts start at UID 1000 on Debian/Ubuntu; system
+	// and service accounts (and "nobody") are excluded.
+	minLoginUID = 1000
+	nobodyUID   = 65534
+)
+
+var errNoSystemPassword = errors.New("account has no usable password")
+
+// pamLogger writes PAM auth diagnostics straight to stderr (captured by
+// journald) so they remain visible even when "Quiet Logs" redirects the default
+// logger to io.Discard. Use pamLogf for anything an operator needs to see when
+// debugging why a system login was accepted or refused.
+var pamLogger = log.New(os.Stderr, "", log.LstdFlags)
+
+func pamLogf(format string, args ...interface{}) { pamLogger.Printf(format, args...) }
+
+// pamAuthEnabled mirrors Config.PAMAuthEnabled and is toggled live on config
+// reload. Guarded atomically so passwordCallback can read it lock-free.
+var pamAuthEnabled atomic.Bool
+
+func setPAMAuthEnabled(v bool) {
+	pamAuthEnabled.Store(v)
+	state := "disabled"
+	if v {
+		state = "ENABLED"
+	}
+	pamLogf("PAM: system (Linux /etc/shadow) login is now %s", state)
+}
+func isPAMAuthEnabled() bool { return pamAuthEnabled.Load() }
+
+// importPAMUser registers a freshly PAM-authenticated account in the running
+// user manager and persists it (marked use_pam) so it shows up in the panel and
+// later logins are re-verified against the system password. Idempotent: a
+// second concurrent/subsequent login for the same user is a no-op.
+func importPAMUser(username string) {
+	cfg := UserConfig{Username: username, UsePAM: true}
+	// Carry over the Linux account expiry (/etc/shadow field 8) so the panel's
+	// "Vence em" shows the real expiration instead of "—".
+	var expPtr *time.Time
+	if exp := shadowAccountExpiry(username); exp != nil {
+		cfg.ExpiresAt = exp.Format(time.RFC3339)
+		expPtr = exp
+	}
+	st := &UserState{Cfg: cfg, ExpiresAt: expPtr}
+	if !userMgr.AddIfAbsent(st) {
+		return // already present in memory
+	}
+	pamLogf("PAM: auto-imported system user %s into the panel", username)
+	if statsStore != nil {
+		if err := statsStore.UpsertUser(context.Background(), cfg); err != nil {
+			pamLogf("PAM: failed to persist auto-imported user %s: %v", username, err)
+		}
+	}
+}
+
+// isRegularLoginUser reports whether username is a regular human login account
+// (UID >= 1000 and not "nobody"), by parsing /etc/passwd. System/service
+// accounts and root are excluded from auto-import.
+func isRegularLoginUser(username string) bool {
+	data, err := os.ReadFile(passwdFile)
+	if err != nil {
+		pamLogf("PAM: cannot read %s: %v", passwdFile, err)
+		return false
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		line = strings.TrimRight(line, "\r")
+		fields := strings.Split(line, ":")
+		if len(fields) < 3 || fields[0] != username {
+			continue
+		}
+		uid, err := strconv.Atoi(fields[2])
+		if err != nil {
+			return false
+		}
+		return uid >= minLoginUID && uid != nobodyUID
+	}
+	return false
+}
+
+// shadowAccountExpiry returns the account expiration date from /etc/shadow
+// field 8 (days since 1970-01-01), or nil if the account never expires (empty
+// field) or the value is unusable. This is the `chage -E` / `useradd -e` date,
+// which maps to the panel's per-user expiry.
+func shadowAccountExpiry(username string) *time.Time {
+	data, err := os.ReadFile(shadowFile)
+	if err != nil {
+		return nil
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		fields := strings.Split(strings.TrimRight(line, "\r"), ":")
+		if len(fields) < 8 || fields[0] != username {
+			continue
+		}
+		expStr := strings.TrimSpace(fields[7])
+		if expStr == "" {
+			return nil // no account expiry set
+		}
+		days, err := strconv.Atoi(expStr)
+		if err != nil || days <= 0 {
+			return nil
+		}
+		t := time.Unix(int64(days)*86400, 0).UTC()
+		return &t
+	}
+	return nil
+}
+
+// authenticatePAM verifies password against the Linux system account matching
+// username. It reads the account's hash from /etc/shadow (the panel runs as
+// root) and recomputes it with the same algorithm — this is the "just the auth"
+// behaviour: the supplied password is checked exactly as the system would,
+// with no account/session management and nothing to do with the SSH daemon.
+//
+// It is called "PAM" for continuity with the user-facing flag, but it does not
+// link libpam; it verifies the crypt(3) hash directly. Supported hash formats:
+// yescrypt ($y$), sha512-crypt ($6$), sha256-crypt ($5$), md5-crypt ($1$),
+// apr1 ($apr1$) and bcrypt ($2a$/$2b$/$2y$). Returns nil on success.
+func authenticatePAM(username, password string) error {
+	if username == "" {
+		return errors.New("shadow: empty username")
+	}
+	hash, err := lookupShadowHash(username)
+	if err != nil {
+		return err
+	}
+	return verifyCryptHash(hash, password)
+}
+
+// lookupShadowHash returns the password hash field for username from /etc/shadow.
+func lookupShadowHash(username string) (string, error) {
+	data, err := os.ReadFile(shadowFile)
+	if err != nil {
+		return "", fmt.Errorf("read %s: %w", shadowFile, err)
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		line = strings.TrimRight(line, "\r")
+		if line == "" {
+			continue
+		}
+		fields := strings.Split(line, ":")
+		if len(fields) < 2 || fields[0] != username {
+			continue
+		}
+		hash := fields[1]
+		// Empty, or locked/disabled accounts (! or * in the hash field) have no
+		// password that any input can match — reject rather than risk a match.
+		if hash == "" || strings.HasPrefix(hash, "!") || strings.HasPrefix(hash, "*") {
+			return "", errNoSystemPassword
+		}
+		return hash, nil
+	}
+	return "", fmt.Errorf("shadow: user %q not found", username)
+}
+
+// verifyCryptHash checks password against a crypt(3)-style hash string,
+// dispatching on the hash prefix. Returns nil only on an exact match.
+func verifyCryptHash(hash, password string) error {
+	switch {
+	case strings.HasPrefix(hash, "$y$"):
+		computed, err := yescrypt.Hash([]byte(password), []byte(hash))
+		if err != nil {
+			return fmt.Errorf("yescrypt: %w", err)
+		}
+		if subtle.ConstantTimeCompare(computed, []byte(hash)) == 1 {
+			return nil
+		}
+		return errors.New("password mismatch")
+	case strings.HasPrefix(hash, "$2a$"), strings.HasPrefix(hash, "$2b$"), strings.HasPrefix(hash, "$2y$"):
+		return bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
+	case crypt.IsHashSupported(hash):
+		return crypt.NewFromHash(hash).Verify(hash, []byte(password))
+	case isTraditionalDES(hash):
+		computed, err := desCrypt(password, hash)
+		if err != nil {
+			return fmt.Errorf("descrypt: %w", err)
+		}
+		if subtle.ConstantTimeCompare([]byte(computed), []byte(hash)) == 1 {
+			return nil
+		}
+		return errors.New("password mismatch")
+	default:
+		return fmt.Errorf("shadow: unsupported hash format")
+	}
+}
+
+// isTraditionalDES reports whether hash looks like a classic 13-character
+// DES crypt(3) hash (2 salt chars + 11 hash chars, all from the crypt alphabet,
+// no "$" scheme prefix). Used by old Linux/UNIX accounts.
+func isTraditionalDES(hash string) bool {
+	if len(hash) != 13 {
+		return false
+	}
+	for i := 0; i < len(hash); i++ {
+		if crypt64Decode(hash[i]) < 0 {
+			return false
+		}
+	}
+	return true
+}

pam_auth_vectors_test.go

@@ -0,0 +1,51 @@
+package main
+
+import "testing"
+
+// Known crypt(3) test vectors covering the formats found in /etc/shadow across
+// old and new Linux. verifyCryptHash must accept the right password and reject
+// the wrong one for each.
+func TestVerifyCryptHashVectors(t *testing.T) {
+	cases := []struct {
+		name string
+		hash string
+		pw   string
+	}{
+		{
+			name: "sha512crypt $6$ (glibc, older Linux)",
+			// openssl passwd -6 -salt saltstring "Hello world!"
+			hash: "$6$saltstring$svn8UoSVapNtMuq1ukKS4tPQd8iKwSMHWjl/O817G3uBnIFNjnQJuesI68u4OTLiBFdcbYEdFCoEOfaS35inz1",
+			pw:   "Hello world!",
+		},
+		{
+			name: "yescrypt $y$ (Debian 11+/Ubuntu 22.04+)",
+			hash: "$y$j9T$e8R9q85ZuzUkArEUurdtS.$esON.7y6H.u3UCPVCpbRFueRpAut2n2cMf1EhpjbuiC",
+			pw:   "pleaseletmein",
+		},
+		{
+			// Real DES-crypt account from the production server's /etc/shadow.
+			name: "traditional DES (old Linux) — testedragon",
+			hash: "pae9A3UKpfaU6",
+			pw:   "testedragon",
+		},
+		{
+			name: "traditional DES (old Linux) — ipv6dragon",
+			hash: "pa9eao3LI6u.6",
+			pw:   "0tMGUL9chq8D",
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if err := verifyCryptHash(c.hash, c.pw); err != nil {
+				t.Errorf("correct password REJECTED: %v", err)
+			}
+			// Build a wrong password that differs in the FIRST character, so the
+			// check is meaningful even for traditional DES (which only considers
+			// the first 8 bytes of the password).
+			wrong := "Z" + c.pw
+			if err := verifyCryptHash(c.hash, wrong); err == nil {
+				t.Errorf("wrong password ACCEPTED")
+			}
+		})
+	}
+}

quota.go

@@ -0,0 +1,361 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"golang.org/x/time/rate"
+)
+
+const (
+	quotaActionBlock    = "block"
+	quotaActionThrottle = "throttle"
+)
+
+var errDataQuotaExceeded = errors.New("data quota exceeded")
+
+func normalizeQuotaAction(v string) string {
+	if strings.EqualFold(strings.TrimSpace(v), quotaActionThrottle) {
+		return quotaActionThrottle
+	}
+	return quotaActionBlock
+}
+
+func quotaThrottleMbpsOrDefault(v int) int {
+	if v <= 0 {
+		return 1
+	}
+	return v
+}
+
+type sshTrafficDelta struct {
+	Uplink   int64
+	Downlink int64
+}
+
+var (
+	sshTrafficPersistenceMu sync.Mutex
+	sshTrafficDirtyMu       sync.Mutex
+	sshTrafficDirty         = make(map[string]*UserState)
+)
+
+func markSSHUserTrafficDirty(u *UserState) {
+	if u == nil || strings.TrimSpace(u.Cfg.Username) == "" {
+		return
+	}
+	sshTrafficDirtyMu.Lock()
+	sshTrafficDirty[u.Cfg.Username] = u
+	sshTrafficDirtyMu.Unlock()
+}
+
+func takeSSHUserTrafficDirty() map[string]*UserState {
+	sshTrafficDirtyMu.Lock()
+	dirty := sshTrafficDirty
+	sshTrafficDirty = make(map[string]*UserState)
+	sshTrafficDirtyMu.Unlock()
+	return dirty
+}
+
+func clearSSHUserTrafficDirty(username string, u *UserState) {
+	sshTrafficDirtyMu.Lock()
+	if current := sshTrafficDirty[username]; u == nil || current == u {
+		delete(sshTrafficDirty, username)
+	}
+	sshTrafficDirtyMu.Unlock()
+}
+
+func (s *Store) AddSSHUserTrafficBatch(ctx context.Context, deltas map[string]sshTrafficDelta) error {
+	if s == nil || len(deltas) == 0 {
+		return nil
+	}
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	stmt, err := tx.PrepareContext(ctx, `
+        UPDATE ssh_users SET
+            total_uplink_bytes   = GREATEST(total_uplink_bytes + GREATEST($2::BIGINT, 0), 0),
+            total_downlink_bytes = GREATEST(total_downlink_bytes + GREATEST($3::BIGINT, 0), 0)
+        WHERE username = $1`)
+	if err != nil {
+		_ = tx.Rollback()
+		return err
+	}
+	defer stmt.Close()
+	for username, d := range deltas {
+		if strings.TrimSpace(username) == "" || (d.Uplink == 0 && d.Downlink == 0) {
+			continue
+		}
+		if _, err := stmt.ExecContext(ctx, username, d.Uplink, d.Downlink); err != nil {
+			_ = tx.Rollback()
+			return err
+		}
+	}
+	return tx.Commit()
+}
+
+func (s *Store) ResetSSHUserTraffic(ctx context.Context, username string) error {
+	if s == nil || strings.TrimSpace(username) == "" {
+		return nil
+	}
+	_, err := s.db.ExecContext(ctx, `
+        UPDATE ssh_users
+        SET total_uplink_bytes = 0, total_downlink_bytes = 0
+        WHERE username = $1`, username)
+	return err
+}
+
+func initSSHRuntimeUsage(u *UserState, uplink, downlink int64) {
+	if u == nil {
+		return
+	}
+	if uplink < 0 {
+		uplink = 0
+	}
+	if downlink < 0 {
+		downlink = 0
+	}
+	atomic.StoreInt64(&u.TotalUplinkBytes, uplink)
+	atomic.StoreInt64(&u.TotalDownlinkBytes, downlink)
+	atomic.StoreInt64(&u.totalBytes, uplink+downlink)
+	atomic.StoreInt64(&u.pendingUplinkBytes, 0)
+	atomic.StoreInt64(&u.pendingDownlinkBytes, 0)
+}
+
+func resetSSHRuntimeUsageLocked(u *UserState) {
+	if u == nil {
+		return
+	}
+	initSSHRuntimeUsage(u, 0, 0)
+	u.mu.Lock()
+	u.quotaLimiter = nil
+	u.quotaLimiterMbps = 0
+	u.mu.Unlock()
+}
+
+func resetSSHRuntimeUsage(username string) {
+	u, ok := userMgr.Get(username)
+	if !ok || u == nil {
+		return
+	}
+	u.trafficMu.Lock()
+	resetSSHRuntimeUsageLocked(u)
+	clearSSHUserTrafficDirty(username, u)
+	u.trafficMu.Unlock()
+}
+
+func resetSSHUserTrafficAccounting(ctx context.Context, store *Store, username string) error {
+	u, _ := userMgr.Get(username)
+	if u != nil {
+		u.trafficMu.Lock()
+		defer u.trafficMu.Unlock()
+	}
+	sshTrafficPersistenceMu.Lock()
+	defer sshTrafficPersistenceMu.Unlock()
+	if err := store.ResetSSHUserTraffic(ctx, username); err != nil {
+		return err
+	}
+	if u != nil {
+		resetSSHRuntimeUsageLocked(u)
+		clearSSHUserTrafficDirty(username, u)
+	}
+	return nil
+}
+
+func sshUserQuotaBlocked(u *UserState) bool {
+	if u == nil {
+		return false
+	}
+	u.mu.Lock()
+	quota := u.Cfg.DataQuotaBytes
+	action := normalizeQuotaAction(u.Cfg.QuotaAction)
+	u.mu.Unlock()
+	return quota > 0 && action == quotaActionBlock && atomic.LoadInt64(&u.totalBytes) >= quota
+}
+
+func sshQuotaLimiter(u *UserState, mbps int) *rate.Limiter {
+	mbps = quotaThrottleMbpsOrDefault(mbps)
+	u.mu.Lock()
+	defer u.mu.Unlock()
+	if u.quotaLimiter == nil || u.quotaLimiterMbps != mbps {
+		bps := mbpsToBytesPerSec(mbps)
+		burst := int(bps)
+		if burst < copyBufSize {
+			burst = copyBufSize
+		}
+		u.quotaLimiter = rate.NewLimiter(rate.Limit(bps), burst)
+		u.quotaLimiterMbps = mbps
+	}
+	return u.quotaLimiter
+}
+
+func reserveSSHUserBytes(u *UserState, requested int) (allowed int, throttle *rate.Limiter, stopAfter bool) {
+	if u == nil || requested <= 0 {
+		return 0, nil, false
+	}
+	u.mu.Lock()
+	quota := u.Cfg.DataQuotaBytes
+	action := normalizeQuotaAction(u.Cfg.QuotaAction)
+	throttleMbps := u.Cfg.QuotaThrottleMbps
+	u.mu.Unlock()
+
+	n := int64(requested)
+	if quota <= 0 {
+		atomic.AddInt64(&u.totalBytes, n)
+		return requested, nil, false
+	}
+
+	if action == quotaActionThrottle {
+		previous := atomic.AddInt64(&u.totalBytes, n) - n
+		if previous+n > quota {
+			return requested, sshQuotaLimiter(u, throttleMbps), false
+		}
+		return requested, nil, false
+	}
+
+	for {
+		used := atomic.LoadInt64(&u.totalBytes)
+		remaining := quota - used
+		if remaining <= 0 {
+			return 0, nil, true
+		}
+		take := n
+		if take > remaining {
+			take = remaining
+		}
+		if atomic.CompareAndSwapInt64(&u.totalBytes, used, used+take) {
+			return int(take), nil, take < n || used+take >= quota
+		}
+	}
+}
+
+func finishSSHUserReservation(u *UserState, uplink bool, reserved, written int) {
+	if u == nil || reserved <= 0 {
+		return
+	}
+	if written < 0 {
+		written = 0
+	}
+	if written > reserved {
+		written = reserved
+	}
+	if written < reserved {
+		atomic.AddInt64(&u.totalBytes, -int64(reserved-written))
+	}
+	if written == 0 {
+		return
+	}
+	if uplink {
+		atomic.AddInt64(&u.TotalUplinkBytes, int64(written))
+		atomic.AddInt64(&u.pendingUplinkBytes, int64(written))
+	} else {
+		atomic.AddInt64(&u.TotalDownlinkBytes, int64(written))
+		atomic.AddInt64(&u.pendingDownlinkBytes, int64(written))
+	}
+	markSSHUserTrafficDirty(u)
+}
+
+type sshQuotaWriter struct {
+	w      io.Writer
+	user   *UserState
+	uplink bool
+	ctx    context.Context
+}
+
+func (qw sshQuotaWriter) Write(p []byte) (int, error) {
+	if qw.user != nil {
+		qw.user.trafficMu.RLock()
+		defer qw.user.trafficMu.RUnlock()
+	}
+	allowed, quotaLimiter, stopAfter := reserveSSHUserBytes(qw.user, len(p))
+	if allowed <= 0 {
+		return 0, errDataQuotaExceeded
+	}
+	if quotaLimiter != nil {
+		ctx := qw.ctx
+		if ctx == nil {
+			ctx = context.Background()
+		}
+		if err := quotaLimiter.WaitN(ctx, allowed); err != nil {
+			finishSSHUserReservation(qw.user, qw.uplink, allowed, 0)
+			return 0, err
+		}
+	}
+	n, err := qw.w.Write(p[:allowed])
+	finishSSHUserReservation(qw.user, qw.uplink, allowed, n)
+	if err != nil {
+		return n, err
+	}
+	if stopAfter || allowed < len(p) {
+		return n, errDataQuotaExceeded
+	}
+	return n, nil
+}
+
+func startSSHUserTrafficFlusher(store *Store) {
+	if store == nil {
+		return
+	}
+	go func() {
+		ticker := time.NewTicker(5 * time.Second)
+		defer ticker.Stop()
+		for range ticker.C {
+			flushSSHUserTraffic(store)
+		}
+	}()
+}
+
+func flushSSHUserTraffic(store *Store) {
+	if store == nil {
+		return
+	}
+	sshTrafficPersistenceMu.Lock()
+	defer sshTrafficPersistenceMu.Unlock()
+	deltas := make(map[string]sshTrafficDelta)
+	states := make(map[string]*UserState)
+	for username, u := range takeSSHUserTrafficDirty() {
+		if u == nil || strings.TrimSpace(username) == "" {
+			continue
+		}
+		up := atomic.SwapInt64(&u.pendingUplinkBytes, 0)
+		down := atomic.SwapInt64(&u.pendingDownlinkBytes, 0)
+		if up == 0 && down == 0 {
+			continue
+		}
+		deltas[username] = sshTrafficDelta{Uplink: up, Downlink: down}
+		states[username] = u
+	}
+	if len(deltas) == 0 {
+		return
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	if err := store.AddSSHUserTrafficBatch(ctx, deltas); err != nil {
+		log.Printf("ssh traffic flush failed: %v", err)
+		for username, d := range deltas {
+			if u := states[username]; u != nil {
+				atomic.AddInt64(&u.pendingUplinkBytes, d.Uplink)
+				atomic.AddInt64(&u.pendingDownlinkBytes, d.Downlink)
+				markSSHUserTrafficDirty(u)
+			}
+		}
+	}
+}
+
+func validateQuotaConfig(quotaBytes int64, action string, throttleMbps int) error {
+	if quotaBytes < 0 {
+		return fmt.Errorf("data_quota_bytes must be non-negative")
+	}
+	action = normalizeQuotaAction(action)
+	if quotaBytes > 0 && action == quotaActionThrottle && throttleMbps < 0 {
+		return fmt.Errorf("quota_throttle_mbps must be non-negative")
+	}
+	return nil
+}

quota_hardening_test.go

@@ -0,0 +1,607 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"golang.org/x/time/rate"
+)
+
+func TestNativeClientMaxConnectionsAndBatchedActiveDelta(t *testing.T) {
+	oldStore := statsStore
+	statsStore = &Store{}
+	defer func() { statsStore = oldStore }()
+
+	const uuid = "11111111-1111-1111-1111-111111111111"
+	m := &XrayManager{
+		nativeQuotaByUUID: map[string]*xrayNativeQuotaState{
+			uuid: {maxConns: 1, generation: 1},
+		},
+	}
+	state := m.nativeQuotaState(uuid)
+
+	release, acquiredState, ok := m.acquireNativeClientConnection(uuid, "user@example")
+	if !ok || release == nil {
+		t.Fatal("first native connection was rejected")
+	}
+	if acquiredState != state {
+		t.Fatal("connection lease did not retain the authenticated policy state")
+	}
+	if _, _, ok := m.acquireNativeClientConnection(uuid, "user@example"); ok {
+		t.Fatal("connection above max_conns was accepted")
+	}
+
+	m.nativeDBMu.Lock()
+	pending := m.nativeActivePending[uuid]
+	m.nativeDBMu.Unlock()
+	if pending.Delta != 1 || !pending.Connected || pending.State != state {
+		t.Fatalf("connect was not queued for batch persistence: %+v", pending)
+	}
+
+	release()
+	release() // idempotent release must not underflow counters.
+
+	m.nativeDBMu.Lock()
+	pending = m.nativeActivePending[uuid]
+	m.nativeDBMu.Unlock()
+	if pending.Delta != 0 || !pending.Connected {
+		t.Fatalf("connect/disconnect batch should net to zero and retain last-active: %+v", pending)
+	}
+
+	state.mu.Lock()
+	active := state.activeConns
+	state.mu.Unlock()
+	if active != 0 {
+		t.Fatalf("active connection count = %d, want 0", active)
+	}
+
+	release2, _, ok := m.acquireNativeClientConnection(uuid, "user@example")
+	if !ok {
+		t.Fatal("slot was not reusable after release")
+	}
+	release2()
+}
+
+func TestRemoveNativeQuotaPolicyPrunesPendingMaps(t *testing.T) {
+	m := &XrayManager{
+		nativeQuotaByUUID: map[string]*xrayNativeQuotaState{
+			"gone": {generation: 1},
+		},
+		nativeTrafficPending: map[string]xrayPendingTraffic{
+			"gone": {Uplink: 10},
+		},
+		nativeActivePending: map[string]xrayPendingActive{
+			"gone": {Delta: 1},
+		},
+	}
+	m.removeNativeQuotaPolicy("gone")
+	if m.nativeQuotaState("gone") != nil {
+		t.Fatal("quota policy was not removed")
+	}
+	m.nativeDBMu.Lock()
+	_, trafficExists := m.nativeTrafficPending["gone"]
+	_, activeExists := m.nativeActivePending["gone"]
+	m.nativeDBMu.Unlock()
+	if trafficExists || activeExists {
+		t.Fatal("deleted UUID remained in a pending persistence map")
+	}
+}
+
+func TestNativeCounterIsBoundedAndReleaseIsIdempotent(t *testing.T) {
+	var active atomicInt64ForTest
+	release1, ok := acquireNativeCounter(&active.Int64, 2)
+	if !ok {
+		t.Fatal("first slot rejected")
+	}
+	release2, ok := acquireNativeCounter(&active.Int64, 2)
+	if !ok {
+		t.Fatal("second slot rejected")
+	}
+	if _, ok := acquireNativeCounter(&active.Int64, 2); ok {
+		t.Fatal("slot above limit accepted")
+	}
+	release1()
+	release1()
+	if got := active.Load(); got != 1 {
+		t.Fatalf("active after double release = %d, want 1", got)
+	}
+	release2()
+	if got := active.Load(); got != 0 {
+		t.Fatalf("active after releases = %d, want 0", got)
+	}
+}
+
+// Embedding keeps the test declaration readable while still passing the exact
+// atomic.Int64 type required by acquireNativeCounter.
+type atomicInt64ForTest struct{ Int64 atomic.Int64 }
+
+func (a *atomicInt64ForTest) Load() int64 { return a.Int64.Load() }
+
+func TestTrackedNativeConnectionsAreClosedOnShutdown(t *testing.T) {
+	oldAccepting := nativeTransportAccepting.Load()
+	defer nativeTransportAccepting.Store(oldAccepting)
+
+	beginNativeTransportAccepting()
+	before := nativeTransportConnections.Load()
+	serverSide, clientSide := net.Pipe()
+	defer clientSide.Close()
+	wrapped, ok := wrapTrackedNativeTransportConn(serverSide)
+	if !ok {
+		t.Fatal("tracked connection was rejected")
+	}
+	if got := nativeTransportConnections.Load(); got != before+1 {
+		t.Fatalf("transport count = %d, want %d", got, before+1)
+	}
+
+	stopNativeTransportAccepting()
+	closeAllNativeTransportConnections()
+	_ = clientSide.SetReadDeadline(time.Now().Add(time.Second))
+	if _, err := clientSide.Read(make([]byte, 1)); err == nil {
+		t.Fatal("peer remained open after native shutdown")
+	}
+	if err := wrapped.Close(); err != nil && !errors.Is(err, net.ErrClosed) {
+		t.Fatalf("second close returned unexpected error: %v", err)
+	}
+	if got := nativeTransportConnections.Load(); got != before {
+		t.Fatalf("transport count after shutdown = %d, want %d", got, before)
+	}
+}
+
+func TestCloseAllXHTTPSessionsReleasesGlobalSlots(t *testing.T) {
+	oldLimit := nativeTuneXHTTPMaxSessions.Load()
+	nativeTuneXHTTPMaxSessions.Store(8)
+	defer nativeTuneXHTTPMaxSessions.Store(oldLimit)
+
+	before := nativeXHTTPSessions.Load()
+	ib := &nativeInbound{xhttpMaxBufferedPosts: 2}
+	for _, id := range []string{"one", "two"} {
+		if sess := ib.upsertXHTTPSession(httptest.NewRecorder(), id); sess == nil {
+			t.Fatalf("session %q was rejected", id)
+		}
+	}
+	if got := nativeXHTTPSessions.Load(); got != before+2 {
+		t.Fatalf("global XHTTP sessions = %d, want %d", got, before+2)
+	}
+	ib.closeAllXHTTPSessions()
+	if got := nativeXHTTPSessions.Load(); got != before {
+		t.Fatalf("global XHTTP sessions after close = %d, want %d", got, before)
+	}
+	ib.xhttpMu.Lock()
+	remaining := len(ib.xhttpSessions)
+	ib.xhttpMu.Unlock()
+	if remaining != 0 {
+		t.Fatalf("inbound retained %d XHTTP sessions", remaining)
+	}
+}
+
+func TestNegativeXHTTPSessionLimitMeansUnlimited(t *testing.T) {
+	old := nativeTuneXHTTPMaxSessions.Load()
+	nativeTuneXHTTPMaxSessions.Store(0)
+	defer nativeTuneXHTTPMaxSessions.Store(old)
+	if got := (&nativeInbound{}).xhttpMaxActiveSessions(); got != 0 {
+		t.Fatalf("unlimited XHTTP session limit normalized to %d", got)
+	}
+}
+
+func TestNativeProtocolGuardsRemainFinite(t *testing.T) {
+	oldRequests := nativeTuneMaxXHTTPRequests.Load()
+	defer nativeTuneMaxXHTTPRequests.Store(oldRequests)
+
+	// Zero is the internal representation of an explicitly disabled application
+	// request counter. HTTP/2 must still retain a finite per-connection guard.
+	nativeTuneMaxXHTTPRequests.Store(0)
+	if got := nativeHTTP2MaxConcurrentStreams(); got != defaultNativeHTTP2MaxStreams {
+		t.Fatalf("HTTP/2 stream guard = %d, want %d", got, defaultNativeHTTP2MaxStreams)
+	}
+
+	nativeTuneMaxXHTTPRequests.Store(32)
+	if got := nativeHTTP2MaxConcurrentStreams(); got != 32 {
+		t.Fatalf("HTTP/2 stream guard did not honor lower request cap: %d", got)
+	}
+	if got := nativeMuxMaxSessionLimit(); got != 64 {
+		t.Fatalf("per-transport Mux session guard = %d, want 64", got)
+	}
+}
+
+func TestXHTTPHandlerDoesNotApplyWebRequestCeiling(t *testing.T) {
+	oldLimit := nativeTuneMaxXHTTPRequests.Load()
+	oldActive := nativeXHTTPRequests.Load()
+	nativeTuneMaxXHTTPRequests.Store(1)
+	nativeXHTTPRequests.Store(1)
+	defer func() {
+		nativeTuneMaxXHTTPRequests.Store(oldLimit)
+		nativeXHTTPRequests.Store(oldActive)
+	}()
+
+	ib := &nativeInbound{transport: "xhttp", path: "/"}
+	req := httptest.NewRequest(http.MethodOptions, "/", nil)
+	rec := httptest.NewRecorder()
+	ib.ServeHTTP(rec, req)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("XHTTP OPTIONS at legacy request ceiling = %d, want 200", rec.Code)
+	}
+}
+
+func TestLegacyXHTTPTuningMigratesToVPNDefaults(t *testing.T) {
+	got := normalizeNativeXrayTuning(&XrayNativeTuning{
+		MuxGlobalSessions:          8192,
+		MaxConcurrentConnections:   4096,
+		MaxConcurrentXHTTPRequests: 8192,
+		XHTTPMaxSessions:           4096,
+	})
+	if got.MuxGlobalSessions != defaultNativeMuxGlobalSessions ||
+		got.MaxConcurrentConnections != defaultNativeMaxConnections ||
+		got.MaxConcurrentXHTTPRequests != defaultNativeMaxXHTTPRequests ||
+		got.XHTTPMaxSessions != defaultNativeXHTTPMaxSessions {
+		t.Fatalf("legacy tuning was not migrated: %+v", got)
+	}
+}
+
+func TestXHTTPMetadataLengthIsBoundedBeforeSessionAllocation(t *testing.T) {
+	ib := &nativeInbound{transport: "xhttp", path: "/"}
+	req := httptest.NewRequest("GET", "/"+strings.Repeat("a", nativeXHTTPMaxSessionIDBytes+1), nil)
+	rec := httptest.NewRecorder()
+	ib.ServeHTTP(rec, req)
+	if rec.Code != 400 {
+		t.Fatalf("oversized XHTTP session id status = %d, want 400", rec.Code)
+	}
+	ib.xhttpMu.Lock()
+	sessions := len(ib.xhttpSessions)
+	ib.xhttpMu.Unlock()
+	if sessions != 0 {
+		t.Fatalf("oversized metadata allocated %d sessions", sessions)
+	}
+}
+
+func TestXHTTPUploadMemoryIsReleasedOnReadAndClose(t *testing.T) {
+	before := nativeXHTTPBufferedBytes.Load()
+	q := newNativeXHTTPUploadQueue(4, 8)
+
+	lease, ok := acquireNativeXHTTPMemory(8)
+	if !ok {
+		t.Fatal("failed to reserve XHTTP test memory")
+	}
+	lease.shrink(4)
+	if err := q.push(context.Background(), nativeXHTTPPacket{Payload: []byte("test"), Seq: 0}, lease); err != nil {
+		lease.release()
+		t.Fatalf("queue push failed: %v", err)
+	}
+	lease.release() // transferred leases are a no-op for the producer.
+	if got := nativeXHTTPBufferedBytes.Load(); got != before+4 {
+		t.Fatalf("buffered bytes after push = %d, want %d", got, before+4)
+	}
+
+	buf := make([]byte, 4)
+	if n, err := q.Read(buf); err != nil || n != 4 || string(buf) != "test" {
+		t.Fatalf("queue read = (%d, %v, %q), want (4, nil, test)", n, err, string(buf))
+	}
+	if got := nativeXHTTPBufferedBytes.Load(); got != before {
+		t.Fatalf("buffered bytes after read = %d, want %d", got, before)
+	}
+
+	lease, ok = acquireNativeXHTTPMemory(3)
+	if !ok {
+		t.Fatal("failed to reserve second XHTTP test memory")
+	}
+	if err := q.push(context.Background(), nativeXHTTPPacket{Payload: []byte("xyz"), Seq: 2}, lease); err != nil {
+		lease.release()
+		t.Fatalf("second queue push failed: %v", err)
+	}
+	lease.release()
+	q.close()
+	if got := nativeXHTTPBufferedBytes.Load(); got != before {
+		t.Fatalf("buffered bytes after close = %d, want %d", got, before)
+	}
+}
+
+func TestXHTTPUploadQueueEnforcesPerSessionByteBudget(t *testing.T) {
+	before := nativeXHTTPBufferedBytes.Load()
+	q := newNativeXHTTPUploadQueue(4, 4)
+	defer q.close()
+
+	lease, ok := acquireNativeXHTTPMemory(5)
+	if !ok {
+		t.Fatal("failed to reserve XHTTP test memory")
+	}
+	defer lease.release()
+	err := q.push(context.Background(), nativeXHTTPPacket{Payload: make([]byte, 5)}, lease)
+	if !errors.Is(err, errNativeXHTTPUploadBufferFull) {
+		t.Fatalf("oversized queue push error = %v, want buffer limit", err)
+	}
+	lease.release()
+	if got := nativeXHTTPBufferedBytes.Load(); got != before {
+		t.Fatalf("rejected payload retained %d bytes, baseline %d", got, before)
+	}
+}
+
+func TestXHTTPUploadQueueBackpressuresInsteadOfRejectingBurst(t *testing.T) {
+	before := nativeXHTTPBufferedBytes.Load()
+	q := newNativeXHTTPUploadQueue(2, 4)
+	defer q.close()
+
+	first, ok := acquireNativeXHTTPMemory(4)
+	if !ok {
+		t.Fatal("failed to reserve first XHTTP payload")
+	}
+	if err := q.push(context.Background(), nativeXHTTPPacket{Payload: []byte("one!"), Seq: 0}, first); err != nil {
+		first.release()
+		t.Fatalf("first queue push failed: %v", err)
+	}
+	first.release()
+
+	second, ok := acquireNativeXHTTPMemory(4)
+	if !ok {
+		t.Fatal("failed to reserve second XHTTP payload")
+	}
+	done := make(chan error, 1)
+	go func() {
+		done <- q.push(context.Background(), nativeXHTTPPacket{Payload: []byte("two!"), Seq: 1}, second)
+	}()
+
+	select {
+	case err := <-done:
+		second.release()
+		t.Fatalf("second burst packet did not backpressure: %v", err)
+	case <-time.After(25 * time.Millisecond):
+	}
+
+	buf := make([]byte, 4)
+	if n, err := q.Read(buf); err != nil || n != 4 || string(buf) != "one!" {
+		second.release()
+		t.Fatalf("first queue read = (%d, %v, %q)", n, err, string(buf))
+	}
+	select {
+	case err := <-done:
+		if err != nil {
+			second.release()
+			t.Fatalf("backpressured packet failed after space released: %v", err)
+		}
+		second.release()
+	case <-time.After(time.Second):
+		second.release()
+		t.Fatal("backpressured packet did not resume")
+	}
+
+	q.close()
+	if got := nativeXHTTPBufferedBytes.Load(); got != before {
+		t.Fatalf("backpressure test leaked %d buffered bytes (baseline %d)", got, before)
+	}
+}
+
+func TestXHTTPBodyReservationUsesActualContentLength(t *testing.T) {
+	ib := &nativeInbound{xhttpMaxEachPostBytes: 1_000_000}
+	req := httptest.NewRequest(http.MethodPost, "/session/0", strings.NewReader("small"))
+	if got := ib.xhttpUploadReservationBytes(req); got != 5 {
+		t.Fatalf("body reservation = %d, want actual payload length 5", got)
+	}
+	req.ContentLength = -1
+	if got := ib.xhttpUploadReservationBytes(req); got != 1_000_000 {
+		t.Fatalf("chunked body reservation = %d, want configured maximum", got)
+	}
+}
+
+func TestNativeQuotaResetWaitsForInFlightTraffic(t *testing.T) {
+	const uuid = "22222222-2222-2222-2222-222222222222"
+	state := &xrayNativeQuotaState{usedBytes: 123, generation: 1}
+	m := &XrayManager{nativeQuotaByUUID: map[string]*xrayNativeQuotaState{uuid: state}}
+
+	state.trafficMu.RLock()
+	done := make(chan struct{})
+	go func() {
+		m.resetNativeQuotaUsage(uuid)
+		close(done)
+	}()
+	select {
+	case <-done:
+		state.trafficMu.RUnlock()
+		t.Fatal("traffic reset crossed an in-flight writer boundary")
+	case <-time.After(25 * time.Millisecond):
+	}
+	state.trafficMu.RUnlock()
+	select {
+	case <-done:
+	case <-time.After(time.Second):
+		t.Fatal("traffic reset did not complete after writer released")
+	}
+	state.mu.Lock()
+	used, generation := state.usedBytes, state.generation
+	state.mu.Unlock()
+	if used != 0 || generation != 2 {
+		t.Fatalf("reset state = used %d generation %d, want 0/2", used, generation)
+	}
+}
+
+func TestNativeRateWaitCanBeCanceled(t *testing.T) {
+	lim := rate.NewLimiter(1, 1)
+	if !lim.AllowN(time.Now(), 1) {
+		t.Fatal("failed to consume initial limiter token")
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	if err := waitNativeRate(ctx, lim, 1); !errors.Is(err, context.Canceled) {
+		t.Fatalf("waitNativeRate error = %v, want context.Canceled", err)
+	}
+}
+
+func TestSSHDirtyQueueDoesNotScanInactiveUsers(t *testing.T) {
+	sshTrafficDirtyMu.Lock()
+	old := sshTrafficDirty
+	sshTrafficDirty = make(map[string]*UserState)
+	sshTrafficDirtyMu.Unlock()
+	defer func() {
+		sshTrafficDirtyMu.Lock()
+		sshTrafficDirty = old
+		sshTrafficDirtyMu.Unlock()
+	}()
+
+	active := &UserState{Cfg: UserConfig{Username: "active"}}
+	inactive := &UserState{Cfg: UserConfig{Username: "inactive"}}
+	markSSHUserTrafficDirty(active)
+	dirty := takeSSHUserTrafficDirty()
+	if len(dirty) != 1 || dirty["active"] != active {
+		t.Fatalf("dirty queue = %#v", dirty)
+	}
+	if _, found := dirty[inactive.Cfg.Username]; found {
+		t.Fatal("inactive user appeared in dirty queue")
+	}
+	if next := takeSSHUserTrafficDirty(); len(next) != 0 {
+		t.Fatalf("dirty queue was not drained: %#v", next)
+	}
+}
+
+func TestOldNativeConnectionCannotDecrementReplacementAccount(t *testing.T) {
+	oldStore := statsStore
+	statsStore = &Store{}
+	defer func() { statsStore = oldStore }()
+
+	const uuid = "replacement-active-user"
+	oldState := &xrayNativeQuotaState{maxConns: 1, generation: 1}
+	m := &XrayManager{nativeQuotaByUUID: map[string]*xrayNativeQuotaState{uuid: oldState}}
+
+	release, acquiredState, ok := m.acquireNativeClientConnection(uuid, "old@example")
+	if !ok || acquiredState != oldState {
+		t.Fatal("failed to acquire old account connection")
+	}
+	// Discard the old account's successful connect delta so this assertion only
+	// measures what happens when that old connection later disconnects.
+	m.nativeDBMu.Lock()
+	m.nativeActivePending = nil
+	m.nativeDBMu.Unlock()
+
+	newState := &xrayNativeQuotaState{maxConns: 1, generation: 1}
+	m.nativeQuotaMu.Lock()
+	m.nativeQuotaByUUID[uuid] = newState
+	m.nativeQuotaMu.Unlock()
+
+	release()
+
+	m.nativeDBMu.Lock()
+	pending := m.nativeActivePending[uuid]
+	m.nativeDBMu.Unlock()
+	if pending.Delta != 0 || pending.State != nil {
+		t.Fatalf("old disconnect was queued against replacement account: %+v", pending)
+	}
+	newState.mu.Lock()
+	active := newState.activeConns
+	newState.mu.Unlock()
+	if active != 0 {
+		t.Fatalf("replacement account active count changed to %d", active)
+	}
+}
+
+func TestOldNativeTrafficCannotAttachToReplacementAccount(t *testing.T) {
+	oldStore := statsStore
+	statsStore = &Store{}
+	defer func() { statsStore = oldStore }()
+
+	const uuid = "replacement-traffic-user"
+	oldState := &xrayNativeQuotaState{generation: 1}
+	newState := &xrayNativeQuotaState{generation: 1}
+	m := &XrayManager{nativeQuotaByUUID: map[string]*xrayNativeQuotaState{uuid: oldState}}
+
+	meter := newTrafficMeter(uuid, "old@example", true, oldState)
+	meter.n = 1234
+
+	m.nativeQuotaMu.Lock()
+	m.nativeQuotaByUUID[uuid] = newState
+	m.nativeQuotaMu.Unlock()
+
+	oldMgr := xrayMgr
+	xrayMgr = m
+	defer func() { xrayMgr = oldMgr }()
+	meter.flush()
+
+	m.nativeDBMu.Lock()
+	pending := m.nativeTrafficPending[uuid]
+	m.nativeDBMu.Unlock()
+	if pending.Uplink != 0 || pending.Downlink != 0 || pending.State != nil {
+		t.Fatalf("old traffic was queued against replacement account: %+v", pending)
+	}
+	m.statsMu.RLock()
+	stat := m.statsByEmail["old@example"]
+	m.statsMu.RUnlock()
+	if stat.Uplink != 0 || stat.Downlink != 0 {
+		t.Fatalf("old traffic resurfaced in runtime stats: %+v", stat)
+	}
+}
+
+func TestNativeFlusherDropsMismatchedPolicyIdentity(t *testing.T) {
+	oldStore := statsStore
+	statsStore = &Store{}
+	defer func() { statsStore = oldStore }()
+
+	const uuid = "identity-prune-user"
+	oldState := &xrayNativeQuotaState{generation: 1}
+	newState := &xrayNativeQuotaState{generation: 1}
+	m := &XrayManager{
+		nativeQuotaByUUID: map[string]*xrayNativeQuotaState{uuid: newState},
+		nativeTrafficPending: map[string]xrayPendingTraffic{
+			uuid: {Email: "old@example", Uplink: 99, State: oldState},
+		},
+		nativeActivePending: map[string]xrayPendingActive{
+			uuid: {Email: "old@example", Delta: -1, State: oldState},
+		},
+	}
+	m.flushNativeStatsToDB()
+
+	m.nativeDBMu.Lock()
+	defer m.nativeDBMu.Unlock()
+	if len(m.nativeTrafficPending) != 0 || len(m.nativeActivePending) != 0 {
+		t.Fatalf("mismatched pending deltas survived prune: traffic=%v active=%v", m.nativeTrafficPending, m.nativeActivePending)
+	}
+}
+
+func TestNativeMuxFinishRunsOnce(t *testing.T) {
+	var calls atomic.Int32
+	s := &nativeMuxSession{
+		closed: make(chan struct{}),
+		uplink: make(chan nativeMuxUplinkItem),
+		onClose: func(*nativeMuxSession) {
+			calls.Add(1)
+		},
+	}
+
+	var wg sync.WaitGroup
+	for i := 0; i < 32; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			s.finish()
+		}()
+	}
+	wg.Wait()
+	if got := calls.Load(); got != 1 {
+		t.Fatalf("mux onClose called %d times, want 1", got)
+	}
+}
+
+type closeTrackingReader struct {
+	closed atomic.Bool
+}
+
+func (r *closeTrackingReader) Read([]byte) (int, error) { return 0, io.EOF }
+func (r *closeTrackingReader) Close() error {
+	r.closed.Store(true)
+	return nil
+}
+
+func TestNativeXHTTPQueueCloseClosesQueuedStreamReader(t *testing.T) {
+	q := newNativeXHTTPUploadQueue(1, 1024)
+	r := &closeTrackingReader{}
+	if err := q.push(context.Background(), nativeXHTTPPacket{Reader: r}, nil); err != nil {
+		t.Fatalf("queue stream reader: %v", err)
+	}
+	q.close()
+	if !r.closed.Load() {
+		t.Fatal("queued stream reader was not closed during queue shutdown")
+	}
+}

security_http.go

@@ -20,8 +20,15 @@ func securePanelHandler(next http.Handler) http.Handler {
 		w.Header().Set("Permissions-Policy", "camera=(), microphone=(), geolocation=(), payment=()")
 		w.Header().Set("Cross-Origin-Opener-Policy", "same-origin")
 		w.Header().Set("Content-Security-Policy", "default-src 'self'; base-uri 'none'; frame-ancestors 'none'; object-src 'none'; form-action 'self'; img-src 'self' data:; connect-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline'")
-		if strings.HasPrefix(r.URL.Path, "/api/") || r.URL.Path == "/" || r.URL.Path == "/index.html" {
-			w.Header().Set("Cache-Control", "no-store")
+		// The panel is deployed in-place by update.sh. Do not let browsers or
+		// reverse proxies keep an older JavaScript bundle after an update, because
+		// stale form serializers can silently omit newly-added config fields.
+		if strings.HasPrefix(r.URL.Path, "/api/") ||
+			r.URL.Path == "/" || r.URL.Path == "/index.html" ||
+			strings.HasPrefix(r.URL.Path, "/assets/") {
+			w.Header().Set("Cache-Control", "no-store, no-cache, must-revalidate")
+			w.Header().Set("Pragma", "no-cache")
+			w.Header().Set("Expires", "0")
 		}
 		if r.Body != nil && r.Method != http.MethodGet && r.Method != http.MethodHead {
 			r.Body = http.MaxBytesReader(w, r.Body, maxAdminRequestBody)

server_config_api.go

@@ -87,6 +87,17 @@ func serverConfigPost(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "config exceeds 512 KiB", http.StatusRequestEntityTooLarge)
 		return
 	}
+	// Keep track of optional field presence separately from its boolean value.
+	// This protects a newly-added setting from being reset by a stale cached
+	// panel bundle that does not know how to send the field yet.
+	var fieldPresence struct {
+		PAMAuthEnabled *bool `json:"pam_auth_enabled"`
+	}
+	if err := json.Unmarshal(body, &fieldPresence); err != nil {
+		http.Error(w, "invalid JSON: "+err.Error(), http.StatusBadRequest)
+		return
+	}
+
 	var newCfg Config
 	if err := json.Unmarshal(body, &newCfg); err != nil {
 		http.Error(w, "invalid JSON: "+err.Error(), http.StatusBadRequest)
@@ -104,6 +115,9 @@ func serverConfigPost(w http.ResponseWriter, r *http.Request) {
 	globalCfgMu.RLock()
 	if globalCfg != nil {
 		newCfg.Users = globalCfg.Users
+		if fieldPresence.PAMAuthEnabled == nil {
+			newCfg.PAMAuthEnabled = globalCfg.PAMAuthEnabled
+		}
 	}
 	globalCfgMu.RUnlock()
 

xray_clients.go

@@ -18,6 +18,9 @@ type XrayClientMeta struct {
 	OwnerUsername      string
 	ExpiresAt          *time.Time
 	MaxConns           int
+	DataQuotaBytes     int64
+	QuotaAction        string
+	QuotaThrottleMbps  int
 	CreatedAt          time.Time
 	TotalUplinkBytes   int64
 	TotalDownlinkBytes int64
@@ -35,6 +38,9 @@ func (s *Store) EnsureXrayClientsSchema(ctx context.Context) error {
 			owner_username        TEXT NOT NULL DEFAULT '',
 			expires_at            TIMESTAMPTZ,
 			max_conns             INT NOT NULL DEFAULT 0,
+			data_quota_bytes      BIGINT NOT NULL DEFAULT 0,
+			quota_action          TEXT NOT NULL DEFAULT 'block',
+			quota_throttle_mbps   INT NOT NULL DEFAULT 1,
 			created_at            TIMESTAMPTZ NOT NULL DEFAULT NOW(),
 			total_uplink_bytes    BIGINT NOT NULL DEFAULT 0,
 			total_downlink_bytes  BIGINT NOT NULL DEFAULT 0,
@@ -42,6 +48,9 @@ func (s *Store) EnsureXrayClientsSchema(ctx context.Context) error {
 			active_connections    INT NOT NULL DEFAULT 0
 		)`,
 		`ALTER TABLE xray_clients ADD COLUMN IF NOT EXISTS owner_username TEXT NOT NULL DEFAULT ''`,
+		`ALTER TABLE xray_clients ADD COLUMN IF NOT EXISTS data_quota_bytes BIGINT NOT NULL DEFAULT 0`,
+		`ALTER TABLE xray_clients ADD COLUMN IF NOT EXISTS quota_action TEXT NOT NULL DEFAULT 'block'`,
+		`ALTER TABLE xray_clients ADD COLUMN IF NOT EXISTS quota_throttle_mbps INT NOT NULL DEFAULT 1`,
 		`ALTER TABLE xray_clients ADD COLUMN IF NOT EXISTS total_uplink_bytes BIGINT NOT NULL DEFAULT 0`,
 		`ALTER TABLE xray_clients ADD COLUMN IF NOT EXISTS total_downlink_bytes BIGINT NOT NULL DEFAULT 0`,
 		`ALTER TABLE xray_clients ADD COLUMN IF NOT EXISTS last_active TIMESTAMPTZ`,
@@ -61,16 +70,20 @@ func (s *Store) UpsertXrayClientMeta(ctx context.Context, m XrayClientMeta) erro
 		expiresAt = *m.ExpiresAt
 	}
 	_, err := s.db.ExecContext(ctx, `
-		INSERT INTO xray_clients (uuid, name, email, inbound_tag, owner_username, expires_at, max_conns)
-		VALUES ($1, $2, $3, $4, $5, $6, $7)
+		INSERT INTO xray_clients (uuid, name, email, inbound_tag, owner_username, expires_at, max_conns, data_quota_bytes, quota_action, quota_throttle_mbps)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
 		ON CONFLICT (uuid) DO UPDATE SET
 			name           = EXCLUDED.name,
 			email          = EXCLUDED.email,
 			inbound_tag    = CASE WHEN EXCLUDED.inbound_tag <> '' THEN EXCLUDED.inbound_tag ELSE xray_clients.inbound_tag END,
 			owner_username = CASE WHEN EXCLUDED.owner_username <> '' THEN EXCLUDED.owner_username ELSE xray_clients.owner_username END,
-			expires_at     = EXCLUDED.expires_at,
-			max_conns      = EXCLUDED.max_conns`,
-		m.UUID, m.Name, m.Email, m.InboundTag, m.OwnerUsername, expiresAt, m.MaxConns)
+			expires_at          = EXCLUDED.expires_at,
+			max_conns           = EXCLUDED.max_conns,
+			data_quota_bytes    = EXCLUDED.data_quota_bytes,
+			quota_action        = EXCLUDED.quota_action,
+			quota_throttle_mbps = EXCLUDED.quota_throttle_mbps`,
+		m.UUID, m.Name, m.Email, m.InboundTag, m.OwnerUsername, expiresAt, m.MaxConns,
+		m.DataQuotaBytes, normalizeQuotaAction(m.QuotaAction), quotaThrottleMbpsOrDefault(m.QuotaThrottleMbps))
 	return err
 }
 
@@ -79,10 +92,13 @@ func (s *Store) GetXrayClientMeta(ctx context.Context, uuid string) (*XrayClient
 	var expiresAt sql.NullTime
 	var lastActive sql.NullTime
 	err := s.db.QueryRowContext(ctx, `
-		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns, created_at,
+		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns,
+		       COALESCE(data_quota_bytes, 0), COALESCE(quota_action, 'block'), COALESCE(quota_throttle_mbps, 1), created_at,
 		       COALESCE(total_uplink_bytes, 0), COALESCE(total_downlink_bytes, 0), last_active, COALESCE(active_connections, 0)
 		FROM xray_clients WHERE uuid = $1`, uuid).
-		Scan(&m.UUID, &m.Name, &m.Email, &m.InboundTag, &m.OwnerUsername, &expiresAt, &m.MaxConns, &m.CreatedAt, &m.TotalUplinkBytes, &m.TotalDownlinkBytes, &lastActive, &m.ActiveConnections)
+		Scan(&m.UUID, &m.Name, &m.Email, &m.InboundTag, &m.OwnerUsername, &expiresAt, &m.MaxConns,
+			&m.DataQuotaBytes, &m.QuotaAction, &m.QuotaThrottleMbps, &m.CreatedAt,
+			&m.TotalUplinkBytes, &m.TotalDownlinkBytes, &lastActive, &m.ActiveConnections)
 	if err != nil {
 		return nil, err
 	}
@@ -96,13 +112,22 @@ func (s *Store) GetXrayClientMeta(ctx context.Context, uuid string) (*XrayClient
 }
 
 func (s *Store) DeleteXrayClientMeta(ctx context.Context, uuid string) error {
+	// Serialize deletion with the native stats flusher. Otherwise a batch that
+	// was swapped out just before DELETE could finish afterward and, if the same
+	// UUID is recreated quickly, apply stale traffic/active deltas to the new row.
+	xrayMgr.nativeTrafficPersistMu.Lock()
+	defer xrayMgr.nativeTrafficPersistMu.Unlock()
 	_, err := s.db.ExecContext(ctx, `DELETE FROM xray_clients WHERE uuid = $1`, uuid)
+	if err == nil {
+		xrayMgr.removeNativeQuotaPolicy(uuid)
+	}
 	return err
 }
 
 func (s *Store) ListAllXrayClients(ctx context.Context) ([]*XrayClientMeta, error) {
 	rows, err := s.db.QueryContext(ctx, `
-		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns, created_at,
+		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns,
+		       COALESCE(data_quota_bytes, 0), COALESCE(quota_action, 'block'), COALESCE(quota_throttle_mbps, 1), created_at,
 		       COALESCE(total_uplink_bytes, 0), COALESCE(total_downlink_bytes, 0), last_active, COALESCE(active_connections, 0)
 		FROM xray_clients ORDER BY created_at DESC`)
 	if err != nil {
@@ -114,7 +139,8 @@ func (s *Store) ListAllXrayClients(ctx context.Context) ([]*XrayClientMeta, erro
 
 func (s *Store) ListXrayClientsByOwner(ctx context.Context, ownerUsername string) ([]*XrayClientMeta, error) {
 	rows, err := s.db.QueryContext(ctx, `
-		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns, created_at,
+		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns,
+		       COALESCE(data_quota_bytes, 0), COALESCE(quota_action, 'block'), COALESCE(quota_throttle_mbps, 1), created_at,
 		       COALESCE(total_uplink_bytes, 0), COALESCE(total_downlink_bytes, 0), last_active, COALESCE(active_connections, 0)
 		FROM xray_clients WHERE owner_username = $1 ORDER BY created_at DESC`, ownerUsername)
 	if err != nil {
@@ -132,7 +158,8 @@ func (s *Store) CountXrayClientsByOwner(ctx context.Context, ownerUsername strin
 
 func (s *Store) ListExpiredXrayClients(ctx context.Context) ([]*XrayClientMeta, error) {
 	rows, err := s.db.QueryContext(ctx, `
-		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns, created_at,
+		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns,
+		       COALESCE(data_quota_bytes, 0), COALESCE(quota_action, 'block'), COALESCE(quota_throttle_mbps, 1), created_at,
 		       COALESCE(total_uplink_bytes, 0), COALESCE(total_downlink_bytes, 0), last_active, COALESCE(active_connections, 0)
 		FROM xray_clients WHERE expires_at IS NOT NULL AND expires_at <= NOW()`)
 	if err != nil {
@@ -148,7 +175,9 @@ func scanXrayClientMetaRows(rows *sql.Rows) ([]*XrayClientMeta, error) {
 		m := &XrayClientMeta{}
 		var expiresAt sql.NullTime
 		var lastActive sql.NullTime
-		if err := rows.Scan(&m.UUID, &m.Name, &m.Email, &m.InboundTag, &m.OwnerUsername, &expiresAt, &m.MaxConns, &m.CreatedAt, &m.TotalUplinkBytes, &m.TotalDownlinkBytes, &lastActive, &m.ActiveConnections); err != nil {
+		if err := rows.Scan(&m.UUID, &m.Name, &m.Email, &m.InboundTag, &m.OwnerUsername, &expiresAt, &m.MaxConns,
+			&m.DataQuotaBytes, &m.QuotaAction, &m.QuotaThrottleMbps, &m.CreatedAt,
+			&m.TotalUplinkBytes, &m.TotalDownlinkBytes, &lastActive, &m.ActiveConnections); err != nil {
 			return nil, err
 		}
 		if expiresAt.Valid {
@@ -204,19 +233,38 @@ func (s *Store) AddXrayClientTrafficBatch(ctx context.Context, deltas map[string
 	return tx.Commit()
 }
 
-// UpdateXrayClientActive adjusts the native online connection counter.
-func (s *Store) UpdateXrayClientActive(ctx context.Context, uuid, email string, delta int) error {
-	if uuid == "" || delta == 0 {
+// AddXrayClientActiveBatch persists native online-counter deltas without
+// launching a database goroutine/query for every connect and disconnect.
+func (s *Store) AddXrayClientActiveBatch(ctx context.Context, deltas map[string]xrayPendingActive) error {
+	if len(deltas) == 0 {
 		return nil
 	}
-	_, err := s.db.ExecContext(ctx, `
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return err
+	}
+	stmt, err := tx.PrepareContext(ctx, `
 		UPDATE xray_clients SET
 			email              = CASE WHEN email = '' AND $2 <> '' THEN $2 ELSE email END,
 			name               = CASE WHEN name = '' AND $2 <> '' THEN $2 ELSE name END,
-			last_active        = CASE WHEN $3::INT > 0 THEN NOW() ELSE last_active END,
+			last_active        = CASE WHEN $4::BOOLEAN THEN NOW() ELSE last_active END,
 			active_connections = GREATEST(active_connections + $3::INT, 0)
-		WHERE uuid = $1`, uuid, email, delta)
-	return err
+		WHERE uuid = $1`)
+	if err != nil {
+		_ = tx.Rollback()
+		return err
+	}
+	defer stmt.Close()
+	for uuid, d := range deltas {
+		if uuid == "" || (d.Delta == 0 && !d.Connected) {
+			continue
+		}
+		if _, err := stmt.ExecContext(ctx, uuid, d.Email, d.Delta, d.Connected); err != nil {
+			_ = tx.Rollback()
+			return err
+		}
+	}
+	return tx.Commit()
 }
 
 func countOwnedXrayClients(ctx context.Context, store *Store, ownerUsername string) int {
@@ -304,3 +352,18 @@ func startXrayClientExpiryChecker(store *Store) {
 		}
 	}()
 }
+
+// ResetXrayClientTraffic clears a client's persistent usage without removing
+// the account or changing its expiry/quota policy.
+func (s *Store) ResetXrayClientTraffic(ctx context.Context, uuid string) error {
+	if s == nil || uuid == "" {
+		return nil
+	}
+	_, err := s.db.ExecContext(ctx, `
+		UPDATE xray_clients SET
+			total_uplink_bytes = 0,
+			total_downlink_bytes = 0,
+			last_active = NULL
+		WHERE uuid = $1`, uuid)
+	return err
+}

xray_config_store.go

@@ -64,7 +64,8 @@ func (s *Store) UpsertXrayConfig(ctx context.Context, configKey string, data []b
 
 func (s *Store) ListXrayClientsByInbound(ctx context.Context, inboundTag string) ([]*XrayClientMeta, error) {
 	rows, err := s.db.QueryContext(ctx, `
-		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns, created_at,
+		SELECT uuid, name, email, inbound_tag, COALESCE(owner_username, ''), expires_at, max_conns,
+		       COALESCE(data_quota_bytes, 0), COALESCE(quota_action, 'block'), COALESCE(quota_throttle_mbps, 1), created_at,
 		       COALESCE(total_uplink_bytes, 0), COALESCE(total_downlink_bytes, 0), last_active, COALESCE(active_connections, 0)
 		FROM xray_clients WHERE inbound_tag = $1 ORDER BY created_at DESC`, inboundTag)
 	if err != nil {

xray_integration.go

@@ -259,8 +259,13 @@ type XrayManager struct {
 	pollStarted   bool
 
 	nativeDBMu              sync.Mutex
+	nativeTrafficPersistMu  sync.Mutex
 	nativeTrafficPending    map[string]xrayPendingTraffic
+	nativeActivePending     map[string]xrayPendingActive
 	nativeStatsFlushStarted bool
+
+	nativeQuotaMu     sync.RWMutex
+	nativeQuotaByUUID map[string]*xrayNativeQuotaState
 }
 
 type xrayTrafficCounters struct {
@@ -280,6 +285,14 @@ type xrayPendingTraffic struct {
 	Email    string
 	Uplink   int64
 	Downlink int64
+	State    *xrayNativeQuotaState
+}
+
+type xrayPendingActive struct {
+	Email     string
+	Delta     int
+	Connected bool
+	State     *xrayNativeQuotaState
 }
 
 var xrayMgr = &XrayManager{}
@@ -296,6 +309,8 @@ func initXrayManager(cfg *XrayConfig) {
 	}
 	xrayMgr.mu.Unlock()
 
+	xrayMgr.reloadNativeQuotaPolicies()
+
 	// In native mode the in-process emulator records traffic directly, so the
 	// external `xray api statsquery` poller is not started (it would overwrite
 	// the native counters with errors from a non-existent CLI endpoint).
@@ -449,7 +464,7 @@ func (m *XrayManager) Restart() error {
 // recordNativeConnect marks a native client stream as online immediately. This
 // is more accurate than external Xray's Stats API polling because it knows when
 // the decoded VMess/VLESS stream is authenticated and opened.
-func (m *XrayManager) recordNativeConnect(uuid, email string) {
+func (m *XrayManager) recordNativeConnect(uuid, email string, state *xrayNativeQuotaState) {
 	uuid = strings.TrimSpace(uuid)
 	email = strings.TrimSpace(email)
 	if email == "" {
@@ -470,18 +485,10 @@ func (m *XrayManager) recordNativeConnect(uuid, email string) {
 	m.statsByEmail[email] = st
 	m.statsMu.Unlock()
 
-	if statsStore != nil && uuid != "" {
-		xrayGo("native xray stats active increment", func() {
-			ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
-			defer cancel()
-			if err := statsStore.UpdateXrayClientActive(ctx, uuid, email, 1); err != nil {
-				xrayLogf("xray native stats: active +1 for %s failed: %v", uuid, err)
-			}
-		})
-	}
+	m.queueNativeActiveDelta(uuid, email, 1, true, state)
 }
 
-func (m *XrayManager) recordNativeDisconnect(uuid, email string) {
+func (m *XrayManager) recordNativeDisconnect(uuid, email string, state *xrayNativeQuotaState) {
 	uuid = strings.TrimSpace(uuid)
 	email = strings.TrimSpace(email)
 	if email == "" {
@@ -500,21 +507,44 @@ func (m *XrayManager) recordNativeDisconnect(uuid, email string) {
 	}
 	m.statsMu.Unlock()
 
-	if statsStore != nil && uuid != "" {
-		xrayGo("native xray stats active decrement", func() {
-			ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
-			defer cancel()
-			if err := statsStore.UpdateXrayClientActive(ctx, uuid, email, -1); err != nil {
-				xrayLogf("xray native stats: active -1 for %s failed: %v", uuid, err)
-			}
-		})
+	m.queueNativeActiveDelta(uuid, email, -1, false, state)
+}
+
+func (m *XrayManager) queueNativeActiveDelta(uuid, email string, delta int, connected bool, state *xrayNativeQuotaState) {
+	if statsStore == nil || uuid == "" || delta == 0 || state == nil {
+		return
 	}
+	// Keep the policy identity stable until the delta is queued. A UUID can be
+	// deleted and later recreated; an old connection must never decrement or add
+	// traffic to the replacement account merely because the string key matches.
+	m.nativeQuotaMu.RLock()
+	if m.nativeQuotaByUUID[uuid] != state {
+		m.nativeQuotaMu.RUnlock()
+		return
+	}
+	m.nativeDBMu.Lock()
+	if m.nativeActivePending == nil {
+		m.nativeActivePending = make(map[string]xrayPendingActive)
+	}
+	p := m.nativeActivePending[uuid]
+	if p.State != nil && p.State != state {
+		p = xrayPendingActive{}
+	}
+	if p.Email == "" {
+		p.Email = email
+	}
+	p.Delta += delta
+	p.Connected = p.Connected || connected
+	p.State = state
+	m.nativeActivePending[uuid] = p
+	m.nativeDBMu.Unlock()
+	m.nativeQuotaMu.RUnlock()
 }
 
 // recordNativeTraffic accumulates in-process byte counters for a client and
 // queues DB persistence. Used by the native emulator instead of external
 // `xray api statsquery` polling.
-func (m *XrayManager) recordNativeTraffic(uuid, email string, up, down int64) {
+func (m *XrayManager) recordNativeTraffic(uuid, email string, up, down int64, generation uint64, state *xrayNativeQuotaState) {
 	uuid = strings.TrimSpace(uuid)
 	email = strings.TrimSpace(email)
 	if email == "" {
@@ -523,6 +553,43 @@ func (m *XrayManager) recordNativeTraffic(uuid, email string, up, down int64) {
 	if email == "" || (up == 0 && down == 0) {
 		return
 	}
+	if state != nil {
+		// Keep generation validation and queuing in the same critical section as
+		// resetNativeTrafficAccounting. Otherwise an old meter can validate just
+		// before a reset and enqueue its bytes immediately after the DB was zeroed.
+		state.mu.Lock()
+		defer state.mu.Unlock()
+		if generation != state.generation {
+			return
+		}
+	}
+
+	// Only DB-backed clients have a native policy state. Config-only clients are
+	// still shown in runtime stats, but queuing UPDATEs for rows that do not exist
+	// can make the retry map grow during a database outage.
+	if statsStore != nil && uuid != "" && state != nil {
+		m.nativeQuotaMu.RLock()
+		if m.nativeQuotaByUUID[uuid] != state {
+			m.nativeQuotaMu.RUnlock()
+			return
+		}
+		m.nativeDBMu.Lock()
+		if m.nativeTrafficPending == nil {
+			m.nativeTrafficPending = make(map[string]xrayPendingTraffic)
+		}
+		p := m.nativeTrafficPending[uuid]
+		if p.State != nil && p.State != state {
+			p = xrayPendingTraffic{}
+		}
+		p.Email = email
+		p.Uplink += up
+		p.Downlink += down
+		p.State = state
+		m.nativeTrafficPending[uuid] = p
+		m.nativeDBMu.Unlock()
+		m.nativeQuotaMu.RUnlock()
+	}
+
 	now := time.Now()
 	m.statsMu.Lock()
 	if m.statsByEmail == nil {
@@ -536,18 +603,6 @@ func (m *XrayManager) recordNativeTraffic(uuid, email string, up, down int64) {
 	m.statsByEmail[email] = st
 	m.statsMu.Unlock()
 
-	if statsStore != nil && uuid != "" {
-		m.nativeDBMu.Lock()
-		if m.nativeTrafficPending == nil {
-			m.nativeTrafficPending = make(map[string]xrayPendingTraffic)
-		}
-		p := m.nativeTrafficPending[uuid]
-		p.Email = email
-		p.Uplink += up
-		p.Downlink += down
-		m.nativeTrafficPending[uuid] = p
-		m.nativeDBMu.Unlock()
-	}
 }
 
 func (m *XrayManager) startNativeStatsFlusher() {
@@ -594,35 +649,108 @@ func (m *XrayManager) flushNativeStatsToDB() {
 	if statsStore == nil {
 		return
 	}
+	m.nativeTrafficPersistMu.Lock()
+	defer m.nativeTrafficPersistMu.Unlock()
+	persistent := m.nativePersistentStates()
 	m.nativeDBMu.Lock()
-	pending := m.nativeTrafficPending
+	for uuid, pending := range m.nativeTrafficPending {
+		if persistent[uuid] != pending.State {
+			delete(m.nativeTrafficPending, uuid)
+		}
+	}
+	for uuid, pending := range m.nativeActivePending {
+		if persistent[uuid] != pending.State {
+			delete(m.nativeActivePending, uuid)
+		}
+	}
+	pendingTraffic := m.nativeTrafficPending
+	pendingActive := m.nativeActivePending
 	m.nativeTrafficPending = nil
+	m.nativeActivePending = nil
 	m.nativeDBMu.Unlock()
-	if len(pending) == 0 {
+	if len(pendingTraffic) == 0 && len(pendingActive) == 0 {
 		return
 	}
-	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-	defer cancel()
-	if err := statsStore.AddXrayClientTrafficBatch(ctx, pending); err != nil {
-		xrayLogf("xray native stats: db traffic flush failed: %v", err)
-		// Put deltas back so a transient DB failure does not lose accounting.
+
+	var trafficErr error
+	if len(pendingTraffic) > 0 {
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		trafficErr = statsStore.AddXrayClientTrafficBatch(ctx, pendingTraffic)
+		cancel()
+	}
+	var activeErr error
+	if len(pendingActive) > 0 {
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		activeErr = statsStore.AddXrayClientActiveBatch(ctx, pendingActive)
+		cancel()
+	}
+
+	if trafficErr != nil {
+		xrayLogf("xray native stats: db traffic flush failed: %v", trafficErr)
+	}
+	if activeErr != nil {
+		xrayLogf("xray native stats: db active flush failed: %v", activeErr)
+	}
+	if trafficErr != nil || activeErr != nil {
+		// Put only failed batches back so a successful write is never duplicated.
+		persistent = m.nativePersistentStates()
 		m.nativeDBMu.Lock()
-		if m.nativeTrafficPending == nil {
+		if trafficErr != nil && m.nativeTrafficPending == nil {
 			m.nativeTrafficPending = make(map[string]xrayPendingTraffic)
 		}
-		for uuid, d := range pending {
-			p := m.nativeTrafficPending[uuid]
-			if p.Email == "" {
-				p.Email = d.Email
+		if trafficErr != nil {
+			for uuid, d := range pendingTraffic {
+				if persistent[uuid] != d.State {
+					continue
+				}
+				p := m.nativeTrafficPending[uuid]
+				if p.State != nil && p.State != d.State {
+					p = xrayPendingTraffic{}
+				}
+				if p.Email == "" {
+					p.Email = d.Email
+				}
+				p.Uplink += d.Uplink
+				p.Downlink += d.Downlink
+				p.State = d.State
+				m.nativeTrafficPending[uuid] = p
+			}
+		}
+		if activeErr != nil && m.nativeActivePending == nil {
+			m.nativeActivePending = make(map[string]xrayPendingActive)
+		}
+		if activeErr != nil {
+			for uuid, d := range pendingActive {
+				if persistent[uuid] != d.State {
+					continue
+				}
+				p := m.nativeActivePending[uuid]
+				if p.State != nil && p.State != d.State {
+					p = xrayPendingActive{}
+				}
+				if p.Email == "" {
+					p.Email = d.Email
+				}
+				p.Delta += d.Delta
+				p.Connected = p.Connected || d.Connected
+				p.State = d.State
+				m.nativeActivePending[uuid] = p
 			}
-			p.Uplink += d.Uplink
-			p.Downlink += d.Downlink
-			m.nativeTrafficPending[uuid] = p
 		}
 		m.nativeDBMu.Unlock()
 	}
 }
 
+func (m *XrayManager) nativePersistentStates() map[string]*xrayNativeQuotaState {
+	m.nativeQuotaMu.RLock()
+	out := make(map[string]*xrayNativeQuotaState, len(m.nativeQuotaByUUID))
+	for uuid, state := range m.nativeQuotaByUUID {
+		out[uuid] = state
+	}
+	m.nativeQuotaMu.RUnlock()
+	return out
+}
+
 // XrayStatusDTO is returned by /api/xray/status.
 type XrayStatusDTO struct {
 	Enabled         bool       `json:"enabled"`
@@ -2027,12 +2155,16 @@ type XrayClientInfo struct {
 	TotalBytes        int64      `json:"total_bytes,omitempty"`
 	ActiveConnections int        `json:"active_connections,omitempty"`
 	// Metadata from PostgreSQL (enriched by handleXrayInbounds)
-	Name           string     `json:"name,omitempty"`
-	ExpiresAt      *time.Time `json:"expires_at,omitempty"`
-	ExpirationDays int        `json:"expiration_days"`
-	MaxConns       int        `json:"max_conns"`
-	OwnerUsername  string     `json:"owner_username,omitempty"`
-	Expired        bool       `json:"expired,omitempty"`
+	Name              string     `json:"name,omitempty"`
+	ExpiresAt         *time.Time `json:"expires_at,omitempty"`
+	ExpirationDays    int        `json:"expiration_days"`
+	MaxConns          int        `json:"max_conns"`
+	DataQuotaBytes    int64      `json:"data_quota_bytes"`
+	QuotaAction       string     `json:"quota_action"`
+	QuotaThrottleMbps int        `json:"quota_throttle_mbps"`
+	QuotaExceeded     bool       `json:"quota_exceeded,omitempty"`
+	OwnerUsername     string     `json:"owner_username,omitempty"`
+	Expired           bool       `json:"expired,omitempty"`
 }
 
 // XrayInboundInfo is returned by /api/xray/inbounds.
@@ -2338,6 +2470,10 @@ func handleXrayInbounds(w http.ResponseWriter, r *http.Request) {
 						Name:              m.Name,
 						ExpiresAt:         m.ExpiresAt,
 						MaxConns:          m.MaxConns,
+						DataQuotaBytes:    m.DataQuotaBytes,
+						QuotaAction:       normalizeQuotaAction(m.QuotaAction),
+						QuotaThrottleMbps: quotaThrottleMbpsOrDefault(m.QuotaThrottleMbps),
+						QuotaExceeded:     m.DataQuotaBytes > 0 && m.TotalUplinkBytes+m.TotalDownlinkBytes >= m.DataQuotaBytes,
 						OwnerUsername:     m.OwnerUsername,
 						UplinkBytes:       m.TotalUplinkBytes,
 						DownlinkBytes:     m.TotalDownlinkBytes,
@@ -2421,6 +2557,7 @@ func applyXrayRuntimeStats(c *XrayClientInfo) {
 		c.DownlinkBytes = st.Downlink
 	}
 	c.TotalBytes = c.UplinkBytes + c.DownlinkBytes
+	c.QuotaExceeded = c.DataQuotaBytes > 0 && c.TotalBytes >= c.DataQuotaBytes
 	if st.ActiveConnections > c.ActiveConnections {
 		c.ActiveConnections = st.ActiveConnections
 	}
@@ -2437,14 +2574,17 @@ func handleXrayClientAdd(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	var req struct {
-		InboundTag     string `json:"inbound_tag"`
-		UUID           string `json:"uuid"`
-		Email          string `json:"email"`
-		Name           string `json:"name"`
-		ExpiresAt      string `json:"expires_at"` // RFC3339 or YYYY-MM-DD or empty
-		MaxConnections int    `json:"max_connections"`
-		OwnerUsername  string `json:"owner_username,omitempty"`
-		ServerID       string `json:"server_id,omitempty"`
+		InboundTag        string `json:"inbound_tag"`
+		UUID              string `json:"uuid"`
+		Email             string `json:"email"`
+		Name              string `json:"name"`
+		ExpiresAt         string `json:"expires_at"` // RFC3339 or YYYY-MM-DD or empty
+		MaxConnections    int    `json:"max_connections"`
+		DataQuotaBytes    int64  `json:"data_quota_bytes"`
+		QuotaAction       string `json:"quota_action"`
+		QuotaThrottleMbps int    `json:"quota_throttle_mbps"`
+		OwnerUsername     string `json:"owner_username,omitempty"`
+		ServerID          string `json:"server_id,omitempty"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
 		http.Error(w, "invalid json", http.StatusBadRequest)
@@ -2454,6 +2594,10 @@ func handleXrayClientAdd(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "inbound_tag and uuid required", http.StatusBadRequest)
 		return
 	}
+	if err := validateQuotaConfig(req.DataQuotaBytes, req.QuotaAction, req.QuotaThrottleMbps); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
 	if ms, remote, err := managedServerFromID(r.Context(), statsStore, req.ServerID); err != nil {
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
@@ -2543,12 +2687,15 @@ func handleXrayClientAdd(w http.ResponseWriter, r *http.Request) {
 	}
 	if statsStore != nil {
 		meta := XrayClientMeta{
-			UUID:          req.UUID,
-			Name:          req.Name,
-			Email:         req.Email,
-			InboundTag:    req.InboundTag,
-			OwnerUsername: ownerUsername,
-			MaxConns:      req.MaxConnections,
+			UUID:              req.UUID,
+			Name:              req.Name,
+			Email:             req.Email,
+			InboundTag:        req.InboundTag,
+			OwnerUsername:     ownerUsername,
+			MaxConns:          req.MaxConnections,
+			DataQuotaBytes:    req.DataQuotaBytes,
+			QuotaAction:       normalizeQuotaAction(req.QuotaAction),
+			QuotaThrottleMbps: quotaThrottleMbpsOrDefault(req.QuotaThrottleMbps),
 		}
 		if req.ExpiresAt != "" {
 			var t time.Time
@@ -2565,6 +2712,8 @@ func handleXrayClientAdd(w http.ResponseWriter, r *http.Request) {
 		}
 		if err := statsStore.UpsertXrayClientMeta(r.Context(), meta); err != nil {
 			xrayLogf("xray: save meta for %s: %v", req.UUID, err)
+		} else {
+			xrayMgr.setNativeQuotaPolicy(&meta)
 		}
 	}
 	xrayMgr.restartIfExternalRunning()
@@ -2579,12 +2728,16 @@ func handleXrayClientUpdate(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	var req struct {
-		UUID           string `json:"uuid"`
-		Name           string `json:"name"`
-		Email          string `json:"email"`
-		ExpiresAt      string `json:"expires_at"`
-		MaxConnections int    `json:"max_connections"`
-		ServerID       string `json:"server_id,omitempty"`
+		UUID              string `json:"uuid"`
+		Name              string `json:"name"`
+		Email             string `json:"email"`
+		ExpiresAt         string `json:"expires_at"`
+		MaxConnections    int    `json:"max_connections"`
+		DataQuotaBytes    int64  `json:"data_quota_bytes"`
+		QuotaAction       string `json:"quota_action"`
+		QuotaThrottleMbps int    `json:"quota_throttle_mbps"`
+		ResetUsage        bool   `json:"reset_usage,omitempty"`
+		ServerID          string `json:"server_id,omitempty"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
 		http.Error(w, "invalid json", http.StatusBadRequest)
@@ -2594,6 +2747,10 @@ func handleXrayClientUpdate(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "uuid required", http.StatusBadRequest)
 		return
 	}
+	if err := validateQuotaConfig(req.DataQuotaBytes, req.QuotaAction, req.QuotaThrottleMbps); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
 	if ms, remote, err := managedServerFromID(r.Context(), statsStore, req.ServerID); err != nil {
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
@@ -2629,12 +2786,17 @@ func handleXrayClientUpdate(w http.ResponseWriter, r *http.Request) {
 	}
 
 	meta := XrayClientMeta{
-		UUID:          req.UUID,
-		Name:          req.Name,
-		Email:         req.Email,
-		InboundTag:    existing.InboundTag,
-		OwnerUsername: existing.OwnerUsername,
-		MaxConns:      req.MaxConnections,
+		UUID:               req.UUID,
+		Name:               req.Name,
+		Email:              req.Email,
+		InboundTag:         existing.InboundTag,
+		OwnerUsername:      existing.OwnerUsername,
+		MaxConns:           req.MaxConnections,
+		DataQuotaBytes:     req.DataQuotaBytes,
+		QuotaAction:        normalizeQuotaAction(req.QuotaAction),
+		QuotaThrottleMbps:  quotaThrottleMbpsOrDefault(req.QuotaThrottleMbps),
+		TotalUplinkBytes:   existing.TotalUplinkBytes,
+		TotalDownlinkBytes: existing.TotalDownlinkBytes,
 	}
 	if req.ExpiresAt != "" {
 		for _, layout := range []string{time.RFC3339, "2006-01-02T15:04", "2006-01-02"} {
@@ -2648,6 +2810,15 @@ func handleXrayClientUpdate(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "update failed: "+err.Error(), http.StatusInternalServerError)
 		return
 	}
+	if req.ResetUsage {
+		if err := xrayMgr.resetNativeTrafficAccounting(r.Context(), statsStore, req.UUID, existing.Email); err != nil {
+			http.Error(w, "usage reset failed: "+err.Error(), http.StatusInternalServerError)
+			return
+		}
+		meta.TotalUplinkBytes = 0
+		meta.TotalDownlinkBytes = 0
+	}
+	xrayMgr.setNativeQuotaPolicy(&meta)
 	if req.Email != "" {
 		if err := xrayMgr.UpdateXrayClientEmail(req.UUID, req.Email); err != nil {
 			xrayLogf("xray: update config email for %s: %v", req.UUID, err)
@@ -2658,6 +2829,70 @@ func handleXrayClientUpdate(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 }
 
+func handleXrayClientResetTraffic(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		return
+	}
+	var req struct {
+		UUID     string `json:"uuid"`
+		ServerID string `json:"server_id,omitempty"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid json", http.StatusBadRequest)
+		return
+	}
+	req.UUID = strings.TrimSpace(req.UUID)
+	if req.UUID == "" {
+		http.Error(w, "uuid required", http.StatusBadRequest)
+		return
+	}
+
+	ctx := r.Context()
+	if ms, remote, err := managedServerFromID(ctx, statsStore, req.ServerID); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	} else if remote {
+		if sess := sessionFromCtx(ctx); sess != nil && sess.Role == RoleReseller && !remoteXrayClientOwned(ctx, ms, req.UUID, sess.Username) {
+			http.Error(w, "forbidden", http.StatusForbidden)
+			return
+		}
+		req.ServerID = ""
+		body, _ := json.Marshal(req)
+		status, data, ct, err := proxyManagedServer(ctx, ms, http.MethodPost, "/api/xray/clients/reset-traffic", body, "application/json")
+		if err != nil {
+			http.Error(w, "remote server error: "+err.Error(), http.StatusBadGateway)
+			return
+		}
+		writeProxyResponse(w, status, data, ct)
+		return
+	}
+	if statsStore == nil {
+		http.Error(w, "storage not available", http.StatusInternalServerError)
+		return
+	}
+
+	existing, err := statsStore.GetXrayClientMeta(ctx, req.UUID)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			http.Error(w, "client not found", http.StatusNotFound)
+		} else {
+			http.Error(w, "database error", http.StatusInternalServerError)
+		}
+		return
+	}
+	if sess := sessionFromCtx(ctx); sess != nil && sess.Role == RoleReseller && existing.OwnerUsername != sess.Username {
+		http.Error(w, "forbidden", http.StatusForbidden)
+		return
+	}
+	if err := xrayMgr.resetNativeTrafficAccounting(ctx, statsStore, req.UUID, existing.Email); err != nil {
+		http.Error(w, "usage reset failed: "+err.Error(), http.StatusInternalServerError)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	_ = json.NewEncoder(w).Encode(map[string]interface{}{"ok": true, "uuid": req.UUID})
+}
+
 func handleXrayClientRemove(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodDelete {
 		w.WriteHeader(http.StatusMethodNotAllowed)

xray_native.go

@@ -138,6 +138,14 @@ func (s *nativeXrayServer) start(configFile string) error {
 	if s.running {
 		return fmt.Errorf("native xray already running")
 	}
+	beginNativeTransportAccepting()
+	started := false
+	defer func() {
+		if !started {
+			stopNativeTransportAccepting()
+			closeAllNativeTransportConnections()
+		}
+	}()
 	if configFile == "" {
 		return fmt.Errorf("native xray: no config file configured")
 	}
@@ -196,9 +204,11 @@ func (s *nativeXrayServer) start(configFile string) error {
 			}
 			return fmt.Errorf("native xray: listen %s (shared XHTTP): %w", addr, err)
 		}
-		serveLn := net.Listener(ln)
+		// Apply the global pre-authentication ceiling before net/http can spawn a
+		// goroutine or begin a TLS handshake for the accepted socket.
+		serveLn := limitNativeListener(ln)
 		if group.security == "tls" {
-			serveLn = tls.NewListener(ln, group.tlsConfig)
+			serveLn = tls.NewListener(serveLn, group.tlsConfig)
 		}
 		opened = append(opened, serveLn)
 		xrayGo(fmt.Sprintf("native xray shared xhttp listener %s", addr), func() { group.serve(serveLn) })
@@ -212,21 +222,34 @@ func (s *nativeXrayServer) start(configFile string) error {
 	s.inboundsByTag = active
 	s.running = true
 	s.startTime = time.Now()
+	started = true
 	return nil
 }
 
 func (s *nativeXrayServer) stop() {
 	s.mu.Lock()
-	defer s.mu.Unlock()
 	if !s.running && len(s.listeners) == 0 {
+		s.mu.Unlock()
 		return
 	}
-	for _, l := range s.listeners {
-		_ = l.Close()
+	stopNativeTransportAccepting()
+	listeners := append([]net.Listener(nil), s.listeners...)
+	inbounds := make([]*nativeInbound, 0, len(s.inboundsByTag))
+	for _, ib := range s.inboundsByTag {
+		inbounds = append(inbounds, ib)
 	}
 	s.listeners = nil
 	s.inboundsByTag = nil
 	s.running = false
+	s.mu.Unlock()
+
+	for _, l := range listeners {
+		_ = l.Close()
+	}
+	closeAllNativeTransportConnections()
+	for _, ib := range inbounds {
+		ib.closeAllXHTTPSessions()
+	}
 	xrayLogf("native xray: stopped")
 }
 
@@ -241,6 +264,12 @@ func (ib *nativeInbound) acceptLoop(ln net.Listener) {
 			xrayLogf("native xray: accept error on %s: %v", ln.Addr(), err)
 			continue
 		}
+		counted, ok := waitWrapTrackedNativeTransportConn(c)
+		if !ok {
+			time.Sleep(nativeOverloadBackoff)
+			continue
+		}
+		c = counted
 		xrayGo(fmt.Sprintf("native xray connection remote=%s", c.RemoteAddr()), func() { ib.serve(c) })
 	}
 }
@@ -262,7 +291,7 @@ func (ib *nativeInbound) serve(raw net.Conn) {
 		tconn := tls.Server(raw, ib.tlsConfig)
 		_ = tconn.SetDeadline(time.Now().Add(tlsHandshakeTimeout))
 		if err := tconn.Handshake(); err != nil {
-			xrayLogf("native xray: tls handshake from %s failed: %v", raw.RemoteAddr(), err)
+			logNativePreAuthRejection("native xray: tls handshake from %s failed: %v", raw.RemoteAddr(), err)
 			return
 		}
 		_ = tconn.SetDeadline(time.Time{})
@@ -275,11 +304,13 @@ func (ib *nativeInbound) serve(raw net.Conn) {
 	case "tcp", "raw", "":
 		// stream is already the protocol stream
 	case "ws", "websocket":
+		_ = conn.SetDeadline(time.Now().Add(tlsHandshakeTimeout))
 		ws, err := wsServerHandshake(conn, ib.path)
 		if err != nil {
-			xrayLogf("native xray: ws handshake from %s failed: %v", raw.RemoteAddr(), err)
+			logNativePreAuthRejection("native xray: ws handshake from %s failed: %v", raw.RemoteAddr(), err)
 			return
 		}
+		_ = conn.SetDeadline(time.Time{})
 		stream = ws
 	case "xhttp", "splithttp":
 		xrayLogf("native xray: inbound %q got raw connection for XHTTP; this transport is served by http.Server", ib.tag)
@@ -331,11 +362,7 @@ const (
 
 func (ib *nativeInbound) handleVLESS(stream net.Conn, remote net.Addr) {
 	defer xrayRecover(fmt.Sprintf("native xray VLESS inbound=%q remote=%s", ib.tag, remote))
-	if ib.isXHTTP() {
-		xrayTracef("native xray: vless handshake start inbound=%q transport=%s remote=%s", ib.tag, ib.transport, remote)
-	} else {
-		xrayLogf("native xray: vless handshake start inbound=%q transport=%s remote=%s", ib.tag, ib.transport, remote)
-	}
+	xrayTracef("native xray: vless handshake start inbound=%q transport=%s remote=%s", ib.tag, ib.transport, remote)
 	_ = stream.SetReadDeadline(time.Now().Add(30 * time.Second))
 
 	head := make([]byte, 1+16+1) // version + uuid + addonLen
@@ -349,7 +376,11 @@ func (ib *nativeInbound) handleVLESS(stream net.Conn, remote net.Addr) {
 
 	client := ib.getNativeClient(id)
 	if client == nil {
-		xrayLogf("native xray: inbound %q rejected unknown VLESS uuid from %s", ib.tag, remote)
+		logNativePreAuthRejection("native xray: inbound %q rejected unknown VLESS uuid from %s", ib.tag, remote)
+		return
+	}
+	if xrayMgr.nativeQuotaBlocked(client.uuid) {
+		xrayLogf("native xray: inbound %q rejected VLESS user %s after data quota", ib.tag, client.email)
 		return
 	}
 
@@ -396,6 +427,18 @@ func (ib *nativeInbound) handleVLESS(stream net.Conn, remote net.Addr) {
 	}
 	_ = stream.SetReadDeadline(time.Time{})
 
+	switch cmd[0] {
+	case vlessCmdTCP, vlessCmdUDP, vlessCmdMux:
+	default:
+		xrayLogf("native xray: inbound %q VLESS command %d not supported yet", ib.tag, cmd[0])
+		return
+	}
+	releaseConnection, quotaState, ok := xrayMgr.acquireNativeClientConnection(client.uuid, client.email)
+	if !ok {
+		return
+	}
+	defer releaseConnection()
+
 	// VLESS response header must be sent before relaying payload. CommandMux is
 	// special: official Xray does not read a target from the VLESS header for it;
 	// the following bytes are Mux.Cool/XUDP frames. Reading port/address here
@@ -413,7 +456,7 @@ func (ib *nativeInbound) handleVLESS(stream net.Conn, remote net.Addr) {
 			return
 		}
 		ib.nativeSuccessLogf("native xray: vless/tcp user=%s src=%s -> %s (inbound %q)", client.email, backend.LocalAddr(), target, ib.tag)
-		nativeTunnel(stream, backend, client.uuid, client.email, ib.upLimiter(), ib.downLimiter())
+		nativeTunnel(stream, backend, client.uuid, client.email, quotaState, ib.upLimiter(), ib.downLimiter())
 	case vlessCmdUDP:
 		backend, target, err := ib.nativeDialUDP(host, port)
 		if err != nil {
@@ -421,12 +464,10 @@ func (ib *nativeInbound) handleVLESS(stream net.Conn, remote net.Addr) {
 			return
 		}
 		ib.nativeSuccessLogf("native xray: vless/udp user=%s src=%s -> %s (inbound %q)", client.email, backend.LocalAddr(), target, ib.tag)
-		nativeVLESSUDPTunnel(stream, backend, client.uuid, client.email, ib.upLimiter(), ib.downLimiter())
+		nativeVLESSUDPTunnel(stream, backend, client.uuid, client.email, quotaState, ib.upLimiter(), ib.downLimiter())
 	case vlessCmdMux:
 		ib.nativeSuccessLogf("native xray: vless/mux user=%s remote=%s (inbound %q)", client.email, remote, ib.tag)
-		ib.nativeVLESSMuxTunnel(stream, client.uuid, client.email)
-	default:
-		xrayLogf("native xray: inbound %q VLESS command %d not supported yet", ib.tag, cmd[0])
+		ib.nativeVLESSMuxTunnel(stream, client.uuid, client.email, quotaState)
 	}
 }
 
@@ -440,7 +481,7 @@ func (ib *nativeInbound) logVLESSReadFailure(stage string, remote net.Addr, emai
 		return
 	}
 	if email == "" {
-		xrayLogf("native xray: vless %s failed inbound=%q transport=%s remote=%s: %v", stage, ib.tag, ib.transport, remote, err)
+		logNativePreAuthRejection("native xray: vless %s failed inbound=%q transport=%s remote=%s: %v", stage, ib.tag, ib.transport, remote, err)
 	} else {
 		xrayLogf("native xray: vless %s failed inbound=%q transport=%s user=%s remote=%s: %v", stage, ib.tag, ib.transport, email, remote, err)
 	}
@@ -657,18 +698,18 @@ func normalizeNativeTargetHost(raw string) string {
 // backend, applying per-direction rate limits and accounting traffic against
 // the client's email so the panel's online detection keeps working. It mirrors
 // handleDirectTCPIP in main.go.
-func nativeTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, email string, up, down *rate.Limiter) {
-	xrayMgr.recordNativeConnect(uuid, email)
-	defer xrayMgr.recordNativeDisconnect(uuid, email)
+func nativeTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, email string, quotaState *xrayNativeQuotaState, up, down *rate.Limiter) {
 	defer xrayRecover(fmt.Sprintf("native xray TCP tunnel user=%s", email))
 
-	upMeter := &trafficMeter{uuid: uuid, email: email, uplink: true}
-	downMeter := &trafficMeter{uuid: uuid, email: email, uplink: false}
+	upMeter := newTrafficMeter(uuid, email, true, quotaState)
+	downMeter := newTrafficMeter(uuid, email, false, quotaState)
 
 	var wg sync.WaitGroup
 	var closeOnce sync.Once
+	ctx, cancel := context.WithCancel(context.Background())
 	closeAll := func() {
 		closeOnce.Do(func() {
+			cancel()
 			_ = backend.Close()
 			_ = client.Close()
 		})
@@ -678,7 +719,7 @@ func nativeTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, email strin
 	xrayGo("native xray TCP uplink", func() { // client -> backend
 		defer wg.Done()
 		defer closeAll()
-		_, _ = copyWithRateLimit(meteredWriter{w: backend, meter: upMeter}, client, up)
+		_, _ = copyWithRateLimitContext(ctx, xrayQuotaMeteredWriter{w: backend, meter: upMeter, ctx: ctx}, client, up)
 		if cw, ok := backend.(interface{ CloseWrite() error }); ok {
 			_ = cw.CloseWrite()
 		}
@@ -688,7 +729,7 @@ func nativeTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, email strin
 	xrayGo("native xray TCP downlink", func() { // backend -> client
 		defer wg.Done()
 		defer closeAll()
-		_, _ = copyWithRateLimit(meteredWriter{w: client, meter: downMeter}, backend, down)
+		_, _ = copyWithRateLimitContext(ctx, xrayQuotaMeteredWriter{w: client, meter: downMeter, ctx: ctx}, backend, down)
 	})
 
 	wg.Wait()
@@ -700,15 +741,24 @@ func nativeTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, email strin
 // trafficMeter accumulates bytes for one direction and flushes them to the
 // stats manager in batches to avoid locking on every write.
 type trafficMeter struct {
-	uuid   string
-	email  string
-	uplink bool
-	n      int64
+	uuid            string
+	email           string
+	uplink          bool
+	n               int64
+	quotaGeneration uint64
+	state           *xrayNativeQuotaState
 }
 
 const trafficFlushThreshold = 1024 * 1024
 
+func newTrafficMeter(uuid, email string, uplink bool, state *xrayNativeQuotaState) *trafficMeter {
+	t := &trafficMeter{uuid: uuid, email: email, uplink: uplink, state: state}
+	t.syncQuotaGeneration()
+	return t
+}
+
 func (t *trafficMeter) add(n int) {
+	t.syncQuotaGeneration()
 	t.n += int64(n)
 	if t.n >= trafficFlushThreshold {
 		t.flush()
@@ -716,29 +766,33 @@ func (t *trafficMeter) add(n int) {
 }
 
 func (t *trafficMeter) flush() {
+	t.syncQuotaGeneration()
 	if t.n == 0 || t.email == "" {
 		return
 	}
 	if t.uplink {
-		xrayMgr.recordNativeTraffic(t.uuid, t.email, t.n, 0)
+		xrayMgr.recordNativeTraffic(t.uuid, t.email, t.n, 0, t.quotaGeneration, t.state)
 	} else {
-		xrayMgr.recordNativeTraffic(t.uuid, t.email, 0, t.n)
+		xrayMgr.recordNativeTraffic(t.uuid, t.email, 0, t.n, t.quotaGeneration, t.state)
 	}
 	t.n = 0
 }
 
-// meteredWriter counts bytes as they are written through to the wrapped writer.
-type meteredWriter struct {
-	w     io.Writer
-	meter *trafficMeter
-}
-
-func (mw meteredWriter) Write(p []byte) (int, error) {
-	n, err := mw.w.Write(p)
-	if n > 0 {
-		mw.meter.add(n)
+func (t *trafficMeter) syncQuotaGeneration() {
+	var generation uint64
+	if t.state != nil {
+		t.state.mu.Lock()
+		generation = t.state.generation
+		t.state.mu.Unlock()
+	}
+	if t.quotaGeneration == 0 {
+		t.quotaGeneration = generation
+		return
+	}
+	if generation != t.quotaGeneration {
+		t.n = 0
+		t.quotaGeneration = generation
 	}
-	return n, err
 }
 
 func (ib *nativeInbound) upLimiter() *rate.Limiter   { return newByteLimiter(ib.upBytesPerSec) }

xray_native_mux.go

@@ -54,7 +54,11 @@ type nativeMuxUplinkItem struct {
 	port    uint16
 }
 
-const nativeMuxUplinkQueue = 64
+const (
+	nativeMuxUplinkQueue                = 16
+	nativeMuxMaxBufferedBytesPerSession = 1 * 1024 * 1024
+	nativeMuxMaxBufferedBytesGlobal     = 128 * 1024 * 1024
+)
 
 var nativeMuxFramePool = sync.Pool{
 	New: func() any {
@@ -91,6 +95,11 @@ type nativeMuxSession struct {
 	uplink      chan nativeMuxUplinkItem
 	closed      chan struct{}
 	closeOnce   sync.Once
+	finishOnce  sync.Once
+	enqueueMu   sync.Mutex
+	enqueueWG   sync.WaitGroup
+	enqueueDone bool
+	buffered    atomic.Int64
 	ctx         context.Context
 	cancel      context.CancelFunc
 	onClose     func(*nativeMuxSession)
@@ -98,7 +107,11 @@ type nativeMuxSession struct {
 	globalID    [8]byte
 }
 
-var nativeMuxGlobalActive atomic.Int64
+var (
+	nativeMuxGlobalActive   atomic.Int64
+	nativeMuxBufferedBytes  atomic.Int64
+	nativeMuxBufferRejected atomic.Int64
+)
 
 func acquireNativeMuxGlobalSlot() (func(), bool) {
 	limit := int64(nativeMuxGlobalSessionLimit())
@@ -117,15 +130,73 @@ func acquireNativeMuxGlobalSlot() (func(), bool) {
 	}
 }
 
+func reserveNativeMuxBufferedBytes(s *nativeMuxSession, n int64) bool {
+	if s == nil || n <= 0 {
+		return true
+	}
+	for {
+		current := s.buffered.Load()
+		if current > nativeMuxMaxBufferedBytesPerSession-n {
+			logNativeLimitRejection("mux session buffered bytes", &nativeMuxBufferRejected, nativeMuxMaxBufferedBytesPerSession)
+			return false
+		}
+		if s.buffered.CompareAndSwap(current, current+n) {
+			break
+		}
+	}
+	for {
+		current := nativeMuxBufferedBytes.Load()
+		if current > nativeMuxMaxBufferedBytesGlobal-n {
+			s.buffered.Add(-n)
+			logNativeLimitRejection("mux global buffered bytes", &nativeMuxBufferRejected, nativeMuxMaxBufferedBytesGlobal)
+			return false
+		}
+		if nativeMuxBufferedBytes.CompareAndSwap(current, current+n) {
+			return true
+		}
+	}
+}
+
+func releaseNativeMuxBufferedBytes(s *nativeMuxSession, n int64) {
+	if s == nil || n <= 0 {
+		return
+	}
+	for {
+		current := s.buffered.Load()
+		release := n
+		if release > current {
+			release = current
+		}
+		if s.buffered.CompareAndSwap(current, current-release) {
+			releaseNativeAtomicBytes(&nativeMuxBufferedBytes, release)
+			return
+		}
+	}
+}
+
+func releaseNativeAtomicBytes(counter *atomic.Int64, n int64) {
+	if counter == nil || n <= 0 {
+		return
+	}
+	for {
+		current := counter.Load()
+		next := current - n
+		if next < 0 {
+			next = 0
+		}
+		if counter.CompareAndSwap(current, next) {
+			return
+		}
+	}
+}
+
 // nativeVLESSMuxTunnel implements the server side of Xray's Mux.Cool framing
 // for VLESS CommandMux. CommandMux does not carry a VLESS target address; every
 // child TCP/UDP request is described by mux frame metadata. UDP is treated as a
 // packet protocol, not as a byte stream, and XUDP-style GlobalID/endpoint
 // metadata is accepted for full-cone friendly clients.
-func (ib *nativeInbound) nativeVLESSMuxTunnel(stream io.ReadWriteCloser, uuid, email string) {
+func (ib *nativeInbound) nativeVLESSMuxTunnel(stream io.ReadWriteCloser, uuid, email string, quotaState *xrayNativeQuotaState) {
 	defer xrayRecover(fmt.Sprintf("native xray VLESS mux user=%s", email))
-	xrayMgr.recordNativeConnect(uuid, email)
-	defer xrayMgr.recordNativeDisconnect(uuid, email)
 
 	writeMu := &sync.Mutex{}
 	sessions := make(map[uint16]*nativeMuxSession)
@@ -256,7 +327,7 @@ func (ib *nativeInbound) nativeVLESSMuxTunnel(stream io.ReadWriteCloser, uuid, e
 				}
 			}
 
-			s, target, err := ib.newNativeMuxSession(meta.sessionID, meta.network, targetHost, targetPort, isXUDP, meta.globalID, stream, writeMu, uuid, email, removeSession)
+			s, target, err := ib.newNativeMuxSession(meta.sessionID, meta.network, targetHost, targetPort, isXUDP, meta.globalID, stream, writeMu, uuid, email, quotaState, removeSession)
 			if err != nil {
 				xrayLogf("native xray: VLESS mux session %s setup failed: %v", target, err)
 				writeMu.Lock()
@@ -281,8 +352,11 @@ func (ib *nativeInbound) nativeVLESSMuxTunnel(stream io.ReadWriteCloser, uuid, e
 			xrayTracef("native xray: vless/mux %s user=%s -> %s session=%d xudp=%v", nativeMuxNetworkName(meta.network), email, target, meta.sessionID, isXUDP)
 			ib2, host2, port2 := ib, targetHost, targetPort
 			xrayGo(fmt.Sprintf("native xray mux session=%d", s.id), func() { s.run(ib2, host2, port2) })
-			if len(pkt.payload) > 0 {
-				s.enqueueUplink(pkt.payload, pkt.host, pkt.port)
+			if len(pkt.payload) > 0 && !s.enqueueUplink(pkt.payload, pkt.host, pkt.port) {
+				closeSession(s.id)
+				writeMu.Lock()
+				_ = writeNativeMuxEnd(stream, meta.sessionID, true)
+				writeMu.Unlock()
 			}
 
 		case nativeMuxStatusKeep:
@@ -319,8 +393,11 @@ func (ib *nativeInbound) nativeVLESSMuxTunnel(stream io.ReadWriteCloser, uuid, e
 				pkt.host = meta.host
 				pkt.port = meta.port
 			}
-			if len(pkt.payload) > 0 {
-				s.enqueueUplink(pkt.payload, pkt.host, pkt.port)
+			if len(pkt.payload) > 0 && !s.enqueueUplink(pkt.payload, pkt.host, pkt.port) {
+				closeSession(s.id)
+				writeMu.Lock()
+				_ = writeNativeMuxEnd(stream, meta.sessionID, true)
+				writeMu.Unlock()
 			}
 
 		default:
@@ -332,7 +409,7 @@ func (ib *nativeInbound) nativeVLESSMuxTunnel(stream io.ReadWriteCloser, uuid, e
 	}
 }
 
-func (ib *nativeInbound) newNativeMuxSession(id uint16, network byte, host string, port uint16, xudp bool, globalID [8]byte, client io.Writer, writeMu *sync.Mutex, uuid, email string, onClose func(*nativeMuxSession)) (*nativeMuxSession, string, error) {
+func (ib *nativeInbound) newNativeMuxSession(id uint16, network byte, host string, port uint16, xudp bool, globalID [8]byte, client io.Writer, writeMu *sync.Mutex, uuid, email string, quotaState *xrayNativeQuotaState, onClose func(*nativeMuxSession)) (*nativeMuxSession, string, error) {
 	target := net.JoinHostPort(normalizeNativeTargetHost(host), strconv.Itoa(int(port)))
 	if invalidNativeDestination(host, port) {
 		return nil, target, fmt.Errorf("invalid destination")
@@ -351,8 +428,8 @@ func (ib *nativeInbound) newNativeMuxSession(id uint16, network byte, host strin
 		email:       email,
 		upLimiter:   ib.upLimiter(),
 		downLimiter: ib.downLimiter(),
-		upMeter:     &trafficMeter{uuid: uuid, email: email, uplink: true},
-		downMeter:   &trafficMeter{uuid: uuid, email: email, uplink: false},
+		upMeter:     newTrafficMeter(uuid, email, true, quotaState),
+		downMeter:   newTrafficMeter(uuid, email, false, quotaState),
 		uplink:      make(chan nativeMuxUplinkItem, nativeMuxUplinkQueue),
 		closed:      make(chan struct{}),
 		onClose:     onClose,
@@ -365,6 +442,7 @@ func (ib *nativeInbound) newNativeMuxSession(id uint16, network byte, host strin
 
 func (s *nativeMuxSession) run(ib *nativeInbound, host string, port uint16) {
 	defer xrayRecover(fmt.Sprintf("native xray mux run session=%d", s.id))
+	defer s.finish()
 
 	select {
 	case <-s.closed:
@@ -410,24 +488,61 @@ func (s *nativeMuxSession) failInit(notifyClient bool) {
 		_ = writeNativeMuxEnd(s.client, s.id, true)
 		s.writeMu.Unlock()
 	}
-	if s.onClose != nil {
-		s.onClose(s)
-	}
-	s.closeBackend()
+	s.finish()
 }
 
-func (s *nativeMuxSession) enqueueUplink(payload []byte, host string, port uint16) {
+// finish is the single lifecycle exit for a mux child. The backend reader,
+// uplink loop, parent mux stream, and initialization path can all detect the
+// terminal condition concurrently, so both cleanup and map removal must be
+// exactly-once operations.
+func (s *nativeMuxSession) finish() {
+	s.finishOnce.Do(func() {
+		s.closeBackend()
+		if s.onClose != nil {
+			s.onClose(s)
+		}
+	})
+}
+
+func (s *nativeMuxSession) beginEnqueue() bool {
+	s.enqueueMu.Lock()
+	defer s.enqueueMu.Unlock()
+	if s.enqueueDone {
+		return false
+	}
+	s.enqueueWG.Add(1)
+	return true
+}
+
+func (s *nativeMuxSession) enqueueUplink(payload []byte, host string, port uint16) bool {
 	if len(payload) == 0 {
-		return
+		return true
+	}
+	if !s.beginEnqueue() {
+		return false
+	}
+	defer s.enqueueWG.Done()
+
+	bytes := int64(len(payload))
+	if !reserveNativeMuxBufferedBytes(s, bytes) {
+		return false
 	}
 	cp := make([]byte, len(payload))
 	copy(cp, payload)
 	select {
 	case s.uplink <- nativeMuxUplinkItem{payload: cp, host: host, port: port}:
+		return true
 	case <-s.closed:
+		releaseNativeMuxBufferedBytes(s, bytes)
+		return false
 	}
 }
 
+func (s *nativeMuxSession) processUplinkItem(item nativeMuxUplinkItem) bool {
+	defer releaseNativeMuxBufferedBytes(s, int64(len(item.payload)))
+	return s.writeBackendItem(item)
+}
+
 func (s *nativeMuxSession) uplinkLoop() {
 	defer s.upMeter.flush()
 	for {
@@ -435,7 +550,7 @@ func (s *nativeMuxSession) uplinkLoop() {
 		case <-s.closed:
 			return
 		case item := <-s.uplink:
-			if !s.writeBackendItem(item) {
+			if !s.processUplinkItem(item) {
 				s.closeBackend()
 				return
 			}
@@ -481,6 +596,13 @@ func (s *nativeMuxSession) writeBackendItem(item nativeMuxUplinkItem) bool {
 			return false
 		}
 	}
+	quotaReservation, quotaErr := reserveNativePacketQuota(s.upMeter, len(payload))
+	if quotaErr != nil {
+		return false
+	}
+	if err := quotaReservation.wait(s.ctx); err != nil {
+		return false
+	}
 
 	var n int
 	var err error
@@ -492,6 +614,7 @@ func (s *nativeMuxSession) writeBackendItem(item nativeMuxUplinkItem) bool {
 			if isNativeDNSSinkTarget(item.host) || invalidNativeDestination(item.host, item.port) {
 				// AdGuard/blocked endpoints must be ignored at the cheapest possible
 				// point. Do not resolve, dial, log loudly, or keep the mux child busy.
+				quotaReservation.finish(0)
 				xrayTracef("native xray: VLESS mux UDP fast-ignored override sink session=%d target=%s:%d", s.id, item.host, item.port)
 				return true
 			}
@@ -503,6 +626,7 @@ func (s *nativeMuxSession) writeBackendItem(item nativeMuxUplinkItem) bool {
 				s.lastUDPPort = item.port
 				s.lastUDPAddr = addr
 			} else {
+				quotaReservation.finish(0)
 				xrayTracef("native xray: VLESS mux UDP override resolve failed session=%d target=%s:%d: %v", s.id, item.host, item.port, rerr)
 				return true
 			}
@@ -512,9 +636,7 @@ func (s *nativeMuxSession) writeBackendItem(item nativeMuxUplinkItem) bool {
 	if s.network == nativeMuxNetworkUDP && err == nil {
 		_ = s.udp.SetReadDeadline(time.Now().Add(nativeMuxUDPIdleTimeout()))
 	}
-	if n > 0 {
-		s.upMeter.add(n)
-	}
+	quotaReservation.finish(n)
 	if err != nil {
 		xrayLogf("native xray: VLESS mux backend write failed session=%d: %v", s.id, err)
 		return false
@@ -532,10 +654,7 @@ func (s *nativeMuxSession) readBackendLoop() {
 			_ = writeNativeMuxEnd(s.client, s.id, false)
 			s.writeMu.Unlock()
 		}
-		if s.onClose != nil {
-			s.onClose(s)
-		}
-		s.closeBackend()
+		s.finish()
 	}()
 
 	if s.network == nativeMuxNetworkTCP {
@@ -571,14 +690,22 @@ func (s *nativeMuxSession) readTCPBackendLoop() {
 		if err := s.waitDownRate(n); err != nil {
 			return
 		}
-		s.downMeter.add(n)
+		quotaReservation, quotaErr := reserveNativePacketQuota(s.downMeter, n)
+		if quotaErr != nil {
+			return
+		}
+		if err := quotaReservation.wait(s.ctx); err != nil {
+			return
+		}
 		s.writeMu.Lock()
 		werr := writeNativeMuxData(s.client, s.id, nativeMuxStatusKeep, buf[:n])
 		s.writeMu.Unlock()
 		if werr != nil {
+			quotaReservation.finish(0)
 			xrayLogf("native xray: VLESS mux TCP client write failed session=%d: %v", s.id, werr)
 			return
 		}
+		quotaReservation.finish(n)
 	}
 }
 
@@ -602,7 +729,13 @@ func (s *nativeMuxSession) readUDPBackendLoop() bool {
 		if err := s.waitDownRate(n); err != nil {
 			return true
 		}
-		s.downMeter.add(n)
+		quotaReservation, quotaErr := reserveNativePacketQuota(s.downMeter, n)
+		if quotaErr != nil {
+			return true
+		}
+		if err := quotaReservation.wait(s.ctx); err != nil {
+			return true
+		}
 		s.writeMu.Lock()
 		// Include the UDP source endpoint on XUDP responses so clients that rely on
 		// full-cone packet addressing can associate the datagram with the correct
@@ -610,27 +743,46 @@ func (s *nativeMuxSession) readUDPBackendLoop() bool {
 		werr := writeNativeMuxPacketData(s.client, s.id, nativeMuxStatusKeep, buf[:n], addr, s.xudp)
 		s.writeMu.Unlock()
 		if werr != nil {
+			quotaReservation.finish(0)
 			xrayLogf("native xray: VLESS mux UDP client write failed session=%d: %v", s.id, werr)
 			return true
 		}
+		quotaReservation.finish(n)
 	}
 }
 
 func (s *nativeMuxSession) closeBackend() {
 	s.closeOnce.Do(func() {
+		s.enqueueMu.Lock()
+		s.enqueueDone = true
 		close(s.closed)
+		s.enqueueMu.Unlock()
 		if s.cancel != nil {
 			s.cancel()
 		}
-		if s.releaseSlot != nil {
-			s.releaseSlot()
-		}
 		if s.tcp != nil {
 			_ = s.tcp.Close()
 		}
 		if s.udp != nil {
 			_ = s.udp.Close()
 		}
+
+		// Wait for producers that passed beginEnqueue before the close flag, then
+		// discard any payloads the consumer did not take. This returns every byte
+		// reservation even when shutdown races a full queue.
+		s.enqueueWG.Wait()
+		for {
+			select {
+			case item := <-s.uplink:
+				releaseNativeMuxBufferedBytes(s, int64(len(item.payload)))
+				item.payload = nil
+			default:
+				if s.releaseSlot != nil {
+					s.releaseSlot()
+				}
+				return
+			}
+		}
 	})
 }
 

xray_native_safety.go

@@ -1,6 +1,14 @@
 package main
 
-import "runtime/debug"
+import (
+	"net"
+	"runtime/debug"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+const nativeOverloadBackoff = 10 * time.Millisecond
 
 // xrayRecover prevents a bad client packet, closed HTTP stream, or mux/session
 // race from taking down the whole sshpanel process. A panic should only kill the
@@ -18,3 +26,269 @@ func xrayGo(where string, fn func()) {
 		fn()
 	}()
 }
+
+func init() {
+	// Direct native-inbound tests and embedders may run an accept loop without
+	// the singleton server start method. Production stop() flips this to false.
+	nativeTransportAccepting.Store(true)
+}
+
+var (
+	nativeTransportConnections  atomic.Int64
+	nativeTransportRejected     atomic.Int64
+	nativeXHTTPRequests         atomic.Int64
+	nativeXHTTPRequestsRejected atomic.Int64
+	nativeXHTTPSessions         atomic.Int64
+	nativeXHTTPSessionsRejected atomic.Int64
+	nativeClientConnsRejected   atomic.Int64
+	nativePreAuthRejected       atomic.Int64
+
+	nativeTransportAccepting atomic.Bool
+	nativeTransportRegistry  = struct {
+		sync.Mutex
+		conns map[*nativeCountedConn]struct{}
+	}{conns: make(map[*nativeCountedConn]struct{})}
+)
+
+// acquireNativeCounter reserves one slot without blocking. Blocking the accept
+// loop or an HTTP handler when the process is already at its safety ceiling
+// would retain yet more sockets/goroutines, so overload is rejected promptly.
+func acquireNativeCounter(active *atomic.Int64, limit int) (func(), bool) {
+	for {
+		current := active.Load()
+		if limit > 0 && current >= int64(limit) {
+			return nil, false
+		}
+		if active.CompareAndSwap(current, current+1) {
+			var once sync.Once
+			return func() {
+				once.Do(func() {
+					if active.Add(-1) < 0 {
+						active.Store(0)
+					}
+				})
+			}, true
+		}
+	}
+}
+
+func shouldLogNativeSample(counter *atomic.Int64) (n int64, ok bool) {
+	n = counter.Add(1)
+	// Keep attacks visible without allowing logging itself to become a CPU/disk
+	// amplifier. The first event and one event per 1024 repetitions are logged.
+	return n, n == 1 || n%1024 == 0
+}
+
+func logNativeLimitRejection(kind string, rejected *atomic.Int64, limit int) {
+	n, ok := shouldLogNativeSample(rejected)
+	if ok {
+		xrayLogf("native xray: rejected %s at safety limit=%d (rejected=%d)", kind, limit, n)
+	}
+}
+
+func logNativeClientLimitRejection(email string, limit int) {
+	n, ok := shouldLogNativeSample(&nativeClientConnsRejected)
+	if ok {
+		xrayLogf("native xray: rejected authenticated user %s at max_conns=%d (rejected=%d)", email, limit, n)
+	}
+}
+
+func logNativePreAuthRejection(format string, args ...interface{}) {
+	if _, ok := shouldLogNativeSample(&nativePreAuthRejected); ok {
+		xrayLogf(format, args...)
+	}
+}
+
+func acquireNativeTransportConnection() (func(), bool) {
+	limit := nativeMaxConnectionLimit()
+	release, ok := acquireNativeCounter(&nativeTransportConnections, limit)
+	if !ok {
+		logNativeLimitRejection("transport connection", &nativeTransportRejected, limit)
+	}
+	return release, ok
+}
+
+func acquireNativeXHTTPRequest() (func(), bool) {
+	limit := nativeMaxXHTTPRequestLimit()
+	release, ok := acquireNativeCounter(&nativeXHTTPRequests, limit)
+	if !ok {
+		logNativeLimitRejection("XHTTP request", &nativeXHTTPRequestsRejected, limit)
+	}
+	return release, ok
+}
+
+func acquireNativeXHTTPSession() (func(), bool) {
+	limit := nativeXHTTPMaxSessionLimit()
+	release, ok := acquireNativeCounter(&nativeXHTTPSessions, limit)
+	if !ok {
+		logNativeLimitRejection("XHTTP session", &nativeXHTTPSessionsRejected, limit)
+	}
+	return release, ok
+}
+
+func configureNativeTransportSocket(c net.Conn) {
+	if tc, ok := c.(*net.TCPConn); ok {
+		_ = tc.SetKeepAlive(true)
+		_ = tc.SetKeepAlivePeriod(30 * time.Second)
+		_ = tc.SetNoDelay(true)
+	}
+}
+
+// nativeCountedConn releases its global transport slot and unregisters itself
+// exactly once, even when several tunnel paths race to close the same socket.
+type nativeCountedConn struct {
+	net.Conn
+	release   func()
+	onClose   func()
+	closeOnce sync.Once
+	closeErr  error
+}
+
+func (c *nativeCountedConn) Close() error {
+	c.closeOnce.Do(func() {
+		c.closeErr = c.Conn.Close()
+		if c.release != nil {
+			c.release()
+		}
+		if c.onClose != nil {
+			c.onClose()
+		}
+	})
+	return c.closeErr
+}
+
+// wrapNativeTransportConn applies only the global counter. It is useful for
+// focused tests and for callers that own connection lifetime themselves.
+func wrapNativeTransportConn(c net.Conn) (net.Conn, bool) {
+	if c == nil {
+		return nil, false
+	}
+	configureNativeTransportSocket(c)
+	release, ok := acquireNativeTransportConnection()
+	if !ok {
+		_ = c.Close()
+		return nil, false
+	}
+	return &nativeCountedConn{Conn: c, release: release}, true
+}
+
+// wrapTrackedNativeTransportConn additionally registers the accepted socket so
+// stopping/restarting native Xray closes established raw, WebSocket, TLS, HTTP/1
+// and HTTP/2 transports instead of leaving tunnel goroutines alive.
+func wrapTrackedNativeTransportConn(c net.Conn) (net.Conn, bool) {
+	if c == nil {
+		return nil, false
+	}
+	configureNativeTransportSocket(c)
+	if !nativeTransportAccepting.Load() {
+		_ = c.Close()
+		return nil, false
+	}
+	release, ok := acquireNativeTransportConnection()
+	if !ok {
+		_ = c.Close()
+		return nil, false
+	}
+	return registerTrackedNativeTransportConn(c, release)
+}
+
+// registerTrackedNativeTransportConn finishes registration when the caller has
+// already reserved a transport slot. Keeping reservation and Accept separate is
+// what lets the production listener apply kernel/socket backpressure instead of
+// accepting and immediately resetting connections at capacity.
+func registerTrackedNativeTransportConn(c net.Conn, release func()) (net.Conn, bool) {
+	counted := &nativeCountedConn{Conn: c, release: release}
+	counted.onClose = func() {
+		nativeTransportRegistry.Lock()
+		delete(nativeTransportRegistry.conns, counted)
+		nativeTransportRegistry.Unlock()
+	}
+
+	nativeTransportRegistry.Lock()
+	if !nativeTransportAccepting.Load() {
+		nativeTransportRegistry.Unlock()
+		_ = counted.Close()
+		return nil, false
+	}
+	nativeTransportRegistry.conns[counted] = struct{}{}
+	nativeTransportRegistry.Unlock()
+	return counted, true
+}
+
+// waitWrapTrackedNativeTransportConn is used by raw native accept loops. It
+// holds at most one already-accepted socket while capacity is busy, leaving the
+// rest in the kernel backlog instead of creating origin-side resets/502s.
+func waitWrapTrackedNativeTransportConn(c net.Conn) (net.Conn, bool) {
+	if c == nil {
+		return nil, false
+	}
+	configureNativeTransportSocket(c)
+	for nativeTransportAccepting.Load() {
+		release, ok := acquireNativeTransportConnection()
+		if ok {
+			return registerTrackedNativeTransportConn(c, release)
+		}
+		time.Sleep(nativeOverloadBackoff)
+	}
+	_ = c.Close()
+	return nil, false
+}
+
+func beginNativeTransportAccepting() {
+	nativeTransportAccepting.Store(true)
+}
+
+func stopNativeTransportAccepting() {
+	nativeTransportAccepting.Store(false)
+}
+
+func closeAllNativeTransportConnections() {
+	nativeTransportRegistry.Lock()
+	conns := make([]*nativeCountedConn, 0, len(nativeTransportRegistry.conns))
+	for c := range nativeTransportRegistry.conns {
+		conns = append(conns, c)
+	}
+	nativeTransportRegistry.Unlock()
+	for _, c := range conns {
+		_ = c.Close()
+	}
+}
+
+// nativeLimitedListener applies the same pre-authentication ceiling to XHTTP
+// listeners. net/http receives only sockets that own a slot; when capacity is
+// busy, new sockets remain in the kernel backlog until a slot becomes available.
+type nativeLimitedListener struct {
+	net.Listener
+}
+
+func (l nativeLimitedListener) Accept() (net.Conn, error) {
+	for {
+		// Reserve before accepting. When the transport is at capacity, connections
+		// remain queued by the kernel rather than being accepted and reset, which is
+		// the behavior CDNs commonly report as an origin 502.
+		release, ok := acquireNativeTransportConnection()
+		if !ok {
+			time.Sleep(nativeOverloadBackoff)
+			continue
+		}
+		c, err := l.Listener.Accept()
+		if err != nil {
+			release()
+			return nil, err
+		}
+		configureNativeTransportSocket(c)
+		if counted, ok := registerTrackedNativeTransportConn(c, release); ok {
+			return counted, nil
+		}
+		// Shutdown may race Accept. Registration closes the socket and releases the
+		// slot; the next Accept observes the listener close.
+		time.Sleep(nativeOverloadBackoff)
+	}
+}
+
+func limitNativeListener(ln net.Listener) net.Listener {
+	if ln == nil {
+		return nil
+	}
+	return nativeLimitedListener{Listener: ln}
+}

xray_native_tuning.go

@@ -7,22 +7,35 @@ import (
 )
 
 type XrayNativeTuning struct {
-	RuntimeGOMAXPROCS int  `json:"runtime_gomaxprocs,omitempty"`
-	MuxGlobalSessions int  `json:"mux_global_sessions,omitempty"`
-	TracePackets      bool `json:"trace_packets,omitempty"`
+	RuntimeGOMAXPROCS          int  `json:"runtime_gomaxprocs,omitempty"`
+	MuxGlobalSessions          int  `json:"mux_global_sessions,omitempty"`
+	MaxConcurrentConnections   int  `json:"max_concurrent_connections,omitempty"`
+	MaxConcurrentXHTTPRequests int  `json:"max_concurrent_xhttp_requests,omitempty"`
+	XHTTPMaxSessions           int  `json:"xhttp_max_sessions,omitempty"`
+	TracePackets               bool `json:"trace_packets,omitempty"`
 }
 
 const (
 	defaultNativeRuntimeGOMAXPROCS = 0
 	defaultNativeMuxGlobalSessions = 32768
+	defaultNativeMaxConnections    = 32768
+	// XHTTP packet handlers are governed by HTTP/2 flow control and bounded byte
+	// queues, not a website-style request ceiling. A negative configured value is
+	// normalized to the internal unlimited representation.
+	defaultNativeMaxXHTTPRequests = -1
 
-	fixedNativeMuxMaxSessions    = 128
+	fixedNativeMuxMaxSessions    = 64
 	fixedNativeMuxUDPIdleMS      = 120000
 	fixedNativeMuxUDPReadBuffer  = 256 * 1024
 	fixedNativeMuxUDPWriteBuffer = 256 * 1024
 
-	defaultNativeXHTTPMaxSessions   = 16384
-	defaultNativeXHTTPBufferedPosts = 512
+	defaultNativeXHTTPMaxSessions = 32768
+	defaultNativeHTTP2MaxStreams  = 1024
+	// Packet-up posts are also protected by byte budgets in xray_xhttp.go. Keep
+	// the default reorder queue modest so thousands of unauthenticated sessions
+	// cannot consume large amounts of memory merely by allocating empty channel
+	// buffers. Operators may request more, up to the hard cap enforced there.
+	defaultNativeXHTTPBufferedPosts = 64
 
 	// Do not impose an application-level lifetime on a connected XHTTP VPN
 	// session. The official Xray server keeps a connected session for the
@@ -35,6 +48,9 @@ const (
 var (
 	nativeTuneRuntimeGOMAXPROCS atomic.Int64
 	nativeTuneMuxGlobalSessions atomic.Int64
+	nativeTuneMaxConnections    atomic.Int64
+	nativeTuneMaxXHTTPRequests  atomic.Int64
+	nativeTuneXHTTPMaxSessions  atomic.Int64
 	nativeTuneTracePackets      atomic.Bool
 )
 
@@ -47,12 +63,33 @@ func normalizeNativeXrayTuning(t *XrayNativeTuning) XrayNativeTuning {
 		t = &XrayNativeTuning{}
 	}
 	out := *t
+	// Migrate the two profiles written by older panel builds. Those defaults were
+	// sized like a web service (4K/8K sessions and a global request cap) and cause
+	// valid high-volume XHTTP VPN traffic to be rejected after an upgrade unless
+	// the persisted values are translated here.
+	legacySafe := out.MaxConcurrentConnections == 4096 && out.MaxConcurrentXHTTPRequests == 8192 && out.XHTTPMaxSessions == 4096
+	legacy2K := out.MaxConcurrentConnections == 8192 && out.MaxConcurrentXHTTPRequests == 16384 && out.XHTTPMaxSessions == 8192
+	if legacySafe || legacy2K {
+		out.MuxGlobalSessions = defaultNativeMuxGlobalSessions
+		out.MaxConcurrentConnections = defaultNativeMaxConnections
+		out.MaxConcurrentXHTTPRequests = defaultNativeMaxXHTTPRequests
+		out.XHTTPMaxSessions = defaultNativeXHTTPMaxSessions
+	}
 	if out.RuntimeGOMAXPROCS < 0 {
 		out.RuntimeGOMAXPROCS = defaultNativeRuntimeGOMAXPROCS
 	}
 	if out.MuxGlobalSessions <= 0 {
 		out.MuxGlobalSessions = defaultNativeMuxGlobalSessions
 	}
+	if out.MaxConcurrentConnections == 0 {
+		out.MaxConcurrentConnections = defaultNativeMaxConnections
+	}
+	if out.MaxConcurrentXHTTPRequests == 0 {
+		out.MaxConcurrentXHTTPRequests = defaultNativeMaxXHTTPRequests
+	}
+	if out.XHTTPMaxSessions == 0 {
+		out.XHTTPMaxSessions = defaultNativeXHTTPMaxSessions
+	}
 	return out
 }
 
@@ -68,19 +105,40 @@ func applyNativeXrayTuning(t *XrayNativeTuning) XrayNativeTuning {
 	runtime.GOMAXPROCS(gomax)
 	nativeTuneRuntimeGOMAXPROCS.Store(int64(gomax))
 	nativeTuneMuxGlobalSessions.Store(int64(out.MuxGlobalSessions))
+	nativeTuneMaxConnections.Store(nativeLimitValue(out.MaxConcurrentConnections))
+	nativeTuneMaxXHTTPRequests.Store(nativeLimitValue(out.MaxConcurrentXHTTPRequests))
+	nativeTuneXHTTPMaxSessions.Store(nativeLimitValue(out.XHTTPMaxSessions))
 	nativeTuneTracePackets.Store(out.TracePackets)
 	return out
 }
 
+// Native tuning limits use zero internally for unlimited. In configuration,
+// zero means "use the safe default" and any negative value disables the cap.
+func nativeLimitValue(v int) int64 {
+	if v < 0 {
+		return 0
+	}
+	return int64(v)
+}
+
 func nativeRuntimeGOMAXPROCS() int     { return int(nativeTuneRuntimeGOMAXPROCS.Load()) }
 func nativeMuxGlobalSessionLimit() int { return int(nativeTuneMuxGlobalSessions.Load()) }
+func nativeMaxConnectionLimit() int    { return int(nativeTuneMaxConnections.Load()) }
+func nativeMaxXHTTPRequestLimit() int  { return int(nativeTuneMaxXHTTPRequests.Load()) }
+func nativeXHTTPMaxSessionLimit() int  { return int(nativeTuneXHTTPMaxSessions.Load()) }
 func nativeTracePacketsEnabled() bool  { return nativeTuneTracePackets.Load() }
 
 func nativeMuxMaxSessionLimit() int     { return fixedNativeMuxMaxSessions }
 func nativeMuxUDPReadBufferSize() int   { return fixedNativeMuxUDPReadBuffer }
 func nativeMuxUDPWriteBufferSize() int  { return fixedNativeMuxUDPWriteBuffer }
-func nativeXHTTPMaxSessionLimit() int   { return defaultNativeXHTTPMaxSessions }
 func nativeXHTTPBufferedPostLimit() int { return defaultNativeXHTTPBufferedPosts }
+func nativeHTTP2MaxConcurrentStreams() uint32 {
+	limit := nativeMaxXHTTPRequestLimit()
+	if limit <= 0 || limit > defaultNativeHTTP2MaxStreams {
+		return defaultNativeHTTP2MaxStreams
+	}
+	return uint32(limit)
+}
 func nativeMuxUDPIdleTimeout() time.Duration {
 	return fixedNativeMuxUDPIdleMS * time.Millisecond
 }

xray_native_udp.go

@@ -25,18 +25,18 @@ const (
 // check and caused the server to block waiting for a fake second payload.
 // XUDP belongs to VLESS CommandMux and is handled separately when Mux support
 // is implemented.
-func nativeVLESSUDPTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, email string, up, down *rate.Limiter) {
-	xrayMgr.recordNativeConnect(uuid, email)
-	defer xrayMgr.recordNativeDisconnect(uuid, email)
+func nativeVLESSUDPTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, email string, quotaState *xrayNativeQuotaState, up, down *rate.Limiter) {
 	defer xrayRecover(fmt.Sprintf("native xray VLESS UDP tunnel user=%s", email))
 
-	upMeter := &trafficMeter{uuid: uuid, email: email, uplink: true}
-	downMeter := &trafficMeter{uuid: uuid, email: email, uplink: false}
+	upMeter := newTrafficMeter(uuid, email, true, quotaState)
+	downMeter := newTrafficMeter(uuid, email, false, quotaState)
 
 	var wg sync.WaitGroup
 	var closeOnce sync.Once
+	ctx, cancel := context.WithCancel(context.Background())
 	closeAll := func() {
 		closeOnce.Do(func() {
+			cancel()
 			_ = backend.Close()
 			_ = client.Close()
 		})
@@ -57,13 +57,18 @@ func nativeVLESSUDPTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, ema
 			if len(payload) == 0 {
 				continue
 			}
-			if err := waitNativeRate(up, len(payload)); err != nil {
+			if err := waitNativeRate(ctx, up, len(payload)); err != nil {
+				return
+			}
+			quotaReservation, err := reserveNativePacketQuota(upMeter, len(payload))
+			if err != nil {
+				return
+			}
+			if err := quotaReservation.wait(ctx); err != nil {
 				return
 			}
 			n, err := backend.Write(payload)
-			if n > 0 {
-				upMeter.add(n)
-			}
+			quotaReservation.finish(n)
 			if err != nil {
 				xrayLogf("native xray: VLESS UDP backend write failed: %v", err)
 				return
@@ -91,14 +96,22 @@ func nativeVLESSUDPTunnel(client io.ReadWriteCloser, backend net.Conn, uuid, ema
 			if n <= 0 {
 				continue
 			}
-			if err := waitNativeRate(down, n); err != nil {
+			if err := waitNativeRate(ctx, down, n); err != nil {
+				return
+			}
+			quotaReservation, err := reserveNativePacketQuota(downMeter, n)
+			if err != nil {
+				return
+			}
+			if err := quotaReservation.wait(ctx); err != nil {
 				return
 			}
 			if err := writeVLESSLengthPacket(client, buf[:n]); err != nil {
+				quotaReservation.finish(0)
 				xrayLogf("native xray: VLESS UDP client write failed: %v", err)
 				return
 			}
-			downMeter.add(n)
+			quotaReservation.finish(n)
 		}
 	})
 
@@ -301,18 +314,18 @@ func writeVLESSXUDPPacket(w io.Writer, payload []byte) error {
 // nativeVMessUDPTunnel maps one VMess body chunk to one UDP datagram. VMess AEAD
 // chunking already preserves packet boundaries, so no extra VLESS length prefix
 // is added inside the encrypted body.
-func nativeVMessUDPTunnel(client nativeVMessStream, backend net.Conn, uuid, email string, up, down *rate.Limiter) {
-	xrayMgr.recordNativeConnect(uuid, email)
-	defer xrayMgr.recordNativeDisconnect(uuid, email)
+func nativeVMessUDPTunnel(client nativeVMessStream, backend net.Conn, uuid, email string, quotaState *xrayNativeQuotaState, up, down *rate.Limiter) {
 	defer xrayRecover(fmt.Sprintf("native xray VMess UDP tunnel user=%s", email))
 
-	upMeter := &trafficMeter{uuid: uuid, email: email, uplink: true}
-	downMeter := &trafficMeter{uuid: uuid, email: email, uplink: false}
+	upMeter := newTrafficMeter(uuid, email, true, quotaState)
+	downMeter := newTrafficMeter(uuid, email, false, quotaState)
 
 	var wg sync.WaitGroup
 	var closeOnce sync.Once
+	ctx, cancel := context.WithCancel(context.Background())
 	closeAll := func() {
 		closeOnce.Do(func() {
+			cancel()
 			_ = backend.Close()
 			_ = client.Close()
 		})
@@ -333,13 +346,18 @@ func nativeVMessUDPTunnel(client nativeVMessStream, backend net.Conn, uuid, emai
 			if len(pkt) == 0 {
 				continue
 			}
-			if err := waitNativeRate(up, len(pkt)); err != nil {
+			if err := waitNativeRate(ctx, up, len(pkt)); err != nil {
+				return
+			}
+			quotaReservation, err := reserveNativePacketQuota(upMeter, len(pkt))
+			if err != nil {
+				return
+			}
+			if err := quotaReservation.wait(ctx); err != nil {
 				return
 			}
 			n, err := backend.Write(pkt)
-			if n > 0 {
-				upMeter.add(n)
-			}
+			quotaReservation.finish(n)
 			if err != nil {
 				xrayLogf("native xray: VMess UDP backend write failed: %v", err)
 				return
@@ -367,14 +385,22 @@ func nativeVMessUDPTunnel(client nativeVMessStream, backend net.Conn, uuid, emai
 			if n <= 0 {
 				continue
 			}
-			if err := waitNativeRate(down, n); err != nil {
+			if err := waitNativeRate(ctx, down, n); err != nil {
+				return
+			}
+			quotaReservation, err := reserveNativePacketQuota(downMeter, n)
+			if err != nil {
+				return
+			}
+			if err := quotaReservation.wait(ctx); err != nil {
 				return
 			}
 			if err := client.WritePacket(buf[:n]); err != nil {
+				quotaReservation.finish(0)
 				xrayLogf("native xray: VMess UDP client write failed: %v", err)
 				return
 			}
-			downMeter.add(n)
+			quotaReservation.finish(n)
 		}
 	})
 
@@ -384,9 +410,12 @@ func nativeVMessUDPTunnel(client nativeVMessStream, backend net.Conn, uuid, emai
 	closeAll()
 }
 
-func waitNativeRate(lim *rate.Limiter, n int) error {
+func waitNativeRate(ctx context.Context, lim *rate.Limiter, n int) error {
 	if lim == nil || n <= 0 {
 		return nil
 	}
-	return lim.WaitN(context.Background(), n)
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return lim.WaitN(ctx, n)
 }

xray_quota.go

@@ -0,0 +1,430 @@
+package main
+
+import (
+	"context"
+	"io"
+	"strings"
+	"sync"
+
+	"golang.org/x/time/rate"
+)
+
+type xrayNativeQuotaState struct {
+	// trafficMu establishes a clean reset boundary. Native stream and packet
+	// writers hold a read lock from quota reservation through the actual write
+	// and metering; traffic resets take the write lock. This prevents an
+	// in-flight pre-reset reservation from being accounted in the new period or
+	// subtracting from freshly reset usage.
+	trafficMu    sync.RWMutex
+	mu           sync.Mutex
+	usedBytes    int64
+	quotaBytes   int64
+	action       string
+	throttleMbps int
+	limiter      *rate.Limiter
+	generation   uint64
+	maxConns     int
+	activeConns  int
+}
+
+func (m *XrayManager) reloadNativeQuotaPolicies() {
+	if statsStore == nil {
+		return
+	}
+	metas, err := statsStore.ListAllXrayClients(context.Background())
+	if err != nil {
+		xrayLogf("xray native quota: load policies failed: %v", err)
+		return
+	}
+	next := make(map[string]*xrayNativeQuotaState, len(metas))
+	for _, meta := range metas {
+		if meta == nil || strings.TrimSpace(meta.UUID) == "" {
+			continue
+		}
+		next[meta.UUID] = newXrayNativeQuotaState(meta)
+	}
+	m.nativeQuotaMu.Lock()
+	m.nativeQuotaByUUID = next
+	m.nativeQuotaMu.Unlock()
+}
+
+func newXrayNativeQuotaState(meta *XrayClientMeta) *xrayNativeQuotaState {
+	used := meta.TotalUplinkBytes + meta.TotalDownlinkBytes
+	if used < 0 {
+		used = 0
+	}
+	return &xrayNativeQuotaState{
+		usedBytes:    used,
+		quotaBytes:   meta.DataQuotaBytes,
+		action:       normalizeQuotaAction(meta.QuotaAction),
+		throttleMbps: quotaThrottleMbpsOrDefault(meta.QuotaThrottleMbps),
+		generation:   1,
+		maxConns:     normalizeXrayMaxConns(meta.MaxConns),
+	}
+}
+
+func normalizeXrayMaxConns(v int) int {
+	if v < 0 {
+		return 0
+	}
+	return v
+}
+
+func (m *XrayManager) setNativeQuotaPolicy(meta *XrayClientMeta) {
+	if meta == nil || strings.TrimSpace(meta.UUID) == "" {
+		return
+	}
+	uuid := strings.TrimSpace(meta.UUID)
+	m.nativeQuotaMu.Lock()
+	if m.nativeQuotaByUUID == nil {
+		m.nativeQuotaByUUID = make(map[string]*xrayNativeQuotaState)
+	}
+	existing := m.nativeQuotaByUUID[uuid]
+	if existing == nil {
+		m.nativeQuotaByUUID[uuid] = newXrayNativeQuotaState(meta)
+		m.nativeQuotaMu.Unlock()
+		return
+	}
+	m.nativeQuotaMu.Unlock()
+
+	existing.mu.Lock()
+	existing.quotaBytes = meta.DataQuotaBytes
+	existing.action = normalizeQuotaAction(meta.QuotaAction)
+	existing.throttleMbps = quotaThrottleMbpsOrDefault(meta.QuotaThrottleMbps)
+	existing.maxConns = normalizeXrayMaxConns(meta.MaxConns)
+	existing.limiter = nil
+	existing.mu.Unlock()
+}
+
+func (m *XrayManager) removeNativeQuotaPolicy(uuid string) {
+	uuid = strings.TrimSpace(uuid)
+	if uuid == "" {
+		return
+	}
+	m.nativeQuotaMu.Lock()
+	delete(m.nativeQuotaByUUID, uuid)
+	m.nativeQuotaMu.Unlock()
+
+	// Do not retain failed traffic/active deltas for a client that no longer
+	// exists. This also bounds the pending maps during a prolonged DB outage.
+	m.nativeDBMu.Lock()
+	delete(m.nativeTrafficPending, uuid)
+	delete(m.nativeActivePending, uuid)
+	m.nativeDBMu.Unlock()
+}
+
+func (m *XrayManager) resetNativeQuotaUsage(uuid string) {
+	uuid = strings.TrimSpace(uuid)
+	m.nativeQuotaMu.RLock()
+	state := m.nativeQuotaByUUID[uuid]
+	m.nativeQuotaMu.RUnlock()
+	if state == nil {
+		return
+	}
+	state.trafficMu.Lock()
+	defer state.trafficMu.Unlock()
+	state.mu.Lock()
+	state.usedBytes = 0
+	state.limiter = nil
+	state.generation++
+	if state.generation == 0 {
+		state.generation = 1
+	}
+	state.mu.Unlock()
+}
+
+func (m *XrayManager) resetNativeTrafficAccounting(ctx context.Context, store *Store, uuid, email string) error {
+	state := m.nativeQuotaState(uuid)
+	if state != nil {
+		state.trafficMu.Lock()
+		defer state.trafficMu.Unlock()
+		state.mu.Lock()
+		defer state.mu.Unlock()
+	}
+
+	m.nativeTrafficPersistMu.Lock()
+	defer m.nativeTrafficPersistMu.Unlock()
+
+	// Remove this client's queued pre-reset delta while holding only the short
+	// map mutex. The database call may take seconds during an outage; keeping
+	// nativeDBMu locked across it would stall traffic/accounting updates for
+	// every other native user and could amplify a slow database into a goroutine
+	// pile-up.
+	m.nativeDBMu.Lock()
+	key := strings.TrimSpace(uuid)
+	var pending xrayPendingTraffic
+	hadPending := false
+	if m.nativeTrafficPending != nil {
+		pending, hadPending = m.nativeTrafficPending[key]
+		delete(m.nativeTrafficPending, key)
+	}
+	m.nativeDBMu.Unlock()
+
+	err := store.ResetXrayClientTraffic(ctx, uuid)
+	if err != nil && hadPending && pending.State == state {
+		m.nativeDBMu.Lock()
+		if m.nativeTrafficPending == nil {
+			m.nativeTrafficPending = make(map[string]xrayPendingTraffic)
+		}
+		current := m.nativeTrafficPending[key]
+		if current.State != nil && current.State != state {
+			current = xrayPendingTraffic{}
+		}
+		if current.Email == "" {
+			current.Email = pending.Email
+		}
+		current.Uplink += pending.Uplink
+		current.Downlink += pending.Downlink
+		current.State = state
+		m.nativeTrafficPending[key] = current
+		m.nativeDBMu.Unlock()
+	}
+	if err != nil {
+		return err
+	}
+	if state != nil {
+		state.usedBytes = 0
+		state.limiter = nil
+		state.generation++
+		if state.generation == 0 {
+			state.generation = 1
+		}
+	}
+
+	m.statsMu.Lock()
+	for _, key := range []string{strings.TrimSpace(email), strings.TrimSpace(uuid)} {
+		if key == "" {
+			continue
+		}
+		if runtime, ok := m.statsByEmail[key]; ok {
+			runtime.Uplink = 0
+			runtime.Downlink = 0
+			m.statsByEmail[key] = runtime
+		}
+	}
+	m.statsMu.Unlock()
+	return nil
+}
+
+func (m *XrayManager) nativeQuotaState(uuid string) *xrayNativeQuotaState {
+	m.nativeQuotaMu.RLock()
+	state := m.nativeQuotaByUUID[strings.TrimSpace(uuid)]
+	m.nativeQuotaMu.RUnlock()
+	return state
+}
+
+// acquireNativeClientConnection enforces the DB-backed max_conns policy across
+// every native inbound and transport. The returned release function is safe to
+// call more than once and keeps runtime/DB online counters in sync.
+func (m *XrayManager) acquireNativeClientConnection(uuid, email string) (func(), *xrayNativeQuotaState, bool) {
+	state := m.nativeQuotaState(uuid)
+	if state != nil {
+		state.mu.Lock()
+		if state.maxConns > 0 && state.activeConns >= state.maxConns {
+			limit := state.maxConns
+			state.mu.Unlock()
+			logNativeClientLimitRejection(email, limit)
+			return nil, state, false
+		}
+		state.activeConns++
+		state.mu.Unlock()
+	}
+
+	m.recordNativeConnect(uuid, email, state)
+	var once sync.Once
+	return func() {
+		once.Do(func() {
+			if state != nil {
+				state.mu.Lock()
+				if state.activeConns > 0 {
+					state.activeConns--
+				}
+				state.mu.Unlock()
+			}
+			m.recordNativeDisconnect(uuid, email, state)
+		})
+	}, state, true
+}
+
+func (m *XrayManager) nativeQuotaBlocked(uuid string) bool {
+	return nativeQuotaStateBlocked(m.nativeQuotaState(uuid))
+}
+
+func nativeQuotaStateBlocked(state *xrayNativeQuotaState) bool {
+	if state == nil {
+		return false
+	}
+	state.mu.Lock()
+	defer state.mu.Unlock()
+	return state.quotaBytes > 0 && normalizeQuotaAction(state.action) == quotaActionBlock && state.usedBytes >= state.quotaBytes
+}
+
+func (m *XrayManager) reserveNativeQuota(state *xrayNativeQuotaState, requested int) (allowed int, limiter *rate.Limiter, stopAfter bool) {
+	if requested <= 0 {
+		return 0, nil, false
+	}
+	if state == nil {
+		return requested, nil, false
+	}
+	state.mu.Lock()
+	defer state.mu.Unlock()
+
+	n := int64(requested)
+	if state.quotaBytes <= 0 {
+		state.usedBytes += n
+		return requested, nil, false
+	}
+	if normalizeQuotaAction(state.action) == quotaActionThrottle {
+		previous := state.usedBytes
+		state.usedBytes += n
+		if previous+n > state.quotaBytes {
+			if state.limiter == nil {
+				bps := mbpsToBytesPerSec(quotaThrottleMbpsOrDefault(state.throttleMbps))
+				burst := int(bps)
+				if burst < copyBufSize {
+					burst = copyBufSize
+				}
+				state.limiter = rate.NewLimiter(rate.Limit(bps), burst)
+			}
+			return requested, state.limiter, false
+		}
+		return requested, nil, false
+	}
+
+	remaining := state.quotaBytes - state.usedBytes
+	if remaining <= 0 {
+		return 0, nil, true
+	}
+	take := n
+	if take > remaining {
+		take = remaining
+	}
+	state.usedBytes += take
+	return int(take), nil, take < n
+}
+
+func (m *XrayManager) finishNativeQuotaReservation(state *xrayNativeQuotaState, reserved, written int) {
+	if reserved <= 0 || written >= reserved {
+		return
+	}
+	if written < 0 {
+		written = 0
+	}
+	if state == nil {
+		return
+	}
+	state.mu.Lock()
+	state.usedBytes -= int64(reserved - written)
+	if state.usedBytes < 0 {
+		state.usedBytes = 0
+	}
+	state.mu.Unlock()
+}
+
+type xrayQuotaMeteredWriter struct {
+	w     io.Writer
+	meter *trafficMeter
+	ctx   context.Context
+}
+
+func (mw xrayQuotaMeteredWriter) Write(p []byte) (int, error) {
+	if mw.meter == nil {
+		return mw.w.Write(p)
+	}
+	state := mw.meter.state
+	if state != nil {
+		state.trafficMu.RLock()
+		defer state.trafficMu.RUnlock()
+	}
+	allowed, limiter, stopAfter := xrayMgr.reserveNativeQuota(state, len(p))
+	if allowed <= 0 {
+		return 0, errDataQuotaExceeded
+	}
+	if limiter != nil {
+		ctx := mw.ctx
+		if ctx == nil {
+			ctx = context.Background()
+		}
+		if err := limiter.WaitN(ctx, allowed); err != nil {
+			xrayMgr.finishNativeQuotaReservation(state, allowed, 0)
+			return 0, err
+		}
+	}
+	n, err := mw.w.Write(p[:allowed])
+	xrayMgr.finishNativeQuotaReservation(state, allowed, n)
+	if n > 0 {
+		mw.meter.add(n)
+	}
+	if err != nil {
+		return n, err
+	}
+	if stopAfter || allowed < len(p) || nativeQuotaStateBlocked(state) {
+		return n, errDataQuotaExceeded
+	}
+	return n, nil
+}
+
+type nativePacketQuotaReservation struct {
+	meter    *trafficMeter
+	state    *xrayNativeQuotaState
+	limiter  *rate.Limiter
+	reserved int
+	finished bool
+}
+
+func reserveNativePacketQuota(meter *trafficMeter, n int) (nativePacketQuotaReservation, error) {
+	if meter == nil || n <= 0 {
+		return nativePacketQuotaReservation{}, nil
+	}
+	state := meter.state
+	if state != nil {
+		state.trafficMu.RLock()
+	}
+	allowed, limiter, stopAfter := xrayMgr.reserveNativeQuota(state, n)
+	if allowed != n || stopAfter {
+		if allowed > 0 {
+			xrayMgr.finishNativeQuotaReservation(state, allowed, 0)
+		}
+		if state != nil {
+			state.trafficMu.RUnlock()
+		}
+		return nativePacketQuotaReservation{}, errDataQuotaExceeded
+	}
+	return nativePacketQuotaReservation{
+		meter:    meter,
+		state:    state,
+		limiter:  limiter,
+		reserved: n,
+	}, nil
+}
+
+func (r *nativePacketQuotaReservation) wait(ctx context.Context) error {
+	if r == nil || r.finished || r.limiter == nil || r.reserved <= 0 {
+		return nil
+	}
+	if err := waitNativeRate(ctx, r.limiter, r.reserved); err != nil {
+		r.finish(0)
+		return err
+	}
+	return nil
+}
+
+func (r *nativePacketQuotaReservation) finish(written int) {
+	if r == nil || r.finished {
+		return
+	}
+	r.finished = true
+	if r.meter == nil || r.reserved <= 0 {
+		if r.state != nil {
+			r.state.trafficMu.RUnlock()
+		}
+		return
+	}
+	xrayMgr.finishNativeQuotaReservation(r.state, r.reserved, written)
+	if written > 0 {
+		r.meter.add(written)
+	}
+	if r.state != nil {
+		r.state.trafficMu.RUnlock()
+	}
+}

xray_vmess.go

@@ -670,7 +670,11 @@ func (ib *nativeInbound) handleVMess(stream net.Conn, remote net.Addr) {
 	}
 	client := ib.matchVMess(authid, time.Now().Unix())
 	if client == nil {
-		log.Printf("native xray: inbound %q rejected unknown/expired VMess auth id from %s", ib.tag, remote)
+		logNativePreAuthRejection("native xray: inbound %q rejected unknown/expired VMess auth id from %s", ib.tag, remote)
+		return
+	}
+	if xrayMgr.nativeQuotaBlocked(client.uuid) {
+		log.Printf("native xray: inbound %q rejected VMess user %s after data quota", ib.tag, client.email)
 		return
 	}
 
@@ -690,6 +694,11 @@ func (ib *nativeInbound) handleVMess(stream net.Conn, remote net.Addr) {
 		log.Printf("native xray: inbound %q VMess command %d not supported yet", ib.tag, req.command)
 		return
 	}
+	releaseConnection, quotaState, ok := xrayMgr.acquireNativeClientConnection(client.uuid, client.email)
+	if !ok {
+		return
+	}
+	defer releaseConnection()
 
 	respBodyKey := sha256.Sum256(req.bodyKey[:])
 	respBodyIV := sha256.Sum256(req.bodyIV[:])
@@ -715,7 +724,7 @@ func (ib *nativeInbound) handleVMess(stream net.Conn, remote net.Addr) {
 			return
 		}
 		log.Printf("native xray: vmess/tcp user=%s src=%s -> %s (inbound %q)", client.email, backend.LocalAddr(), target, ib.tag)
-		nativeTunnel(vc, backend, client.uuid, client.email, ib.upLimiter(), ib.downLimiter())
+		nativeTunnel(vc, backend, client.uuid, client.email, quotaState, ib.upLimiter(), ib.downLimiter())
 	case vmessCmdUDP:
 		backend, target, err := ib.nativeDialUDP(req.host, req.port)
 		if err != nil {
@@ -723,6 +732,6 @@ func (ib *nativeInbound) handleVMess(stream net.Conn, remote net.Addr) {
 			return
 		}
 		log.Printf("native xray: vmess/udp user=%s src=%s -> %s (inbound %q)", client.email, backend.LocalAddr(), target, ib.tag)
-		nativeVMessUDPTunnel(vc, backend, client.uuid, client.email, ib.upLimiter(), ib.downLimiter())
+		nativeVMessUDPTunnel(vc, backend, client.uuid, client.email, quotaState, ib.upLimiter(), ib.downLimiter())
 	}
 }

xray_xhttp.go

@@ -14,12 +14,35 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/h2c"
 )
 
+const nativeXHTTPServerIdleTimeout = 90 * time.Second
+
+const (
+	nativeXHTTPMaxSessionIDBytes             = 256
+	nativeXHTTPMaxSequenceBytes              = 20
+	nativeXHTTPHardMaxHeaderBytes            = 256 * 1024
+	nativeXHTTPHardMaxPostBytes        int64 = 16 * 1024 * 1024
+	nativeXHTTPMaxBufferedPosts              = 512
+	nativeXHTTPMaxBufferedSessionBytes       = 16 * 1024 * 1024
+	nativeXHTTPMaxBufferedGlobalBytes        = 128 * 1024 * 1024
+)
+
+var (
+	nativeXHTTPBufferedBytes       atomic.Int64
+	nativeXHTTPBufferRejected      atomic.Int64
+	errNativeXHTTPUploadBufferFull = errors.New("xhttp upload buffer limit reached")
+	nativeXHTTPMemoryWait          = struct {
+		sync.Mutex
+		changed chan struct{}
+	}{changed: make(chan struct{})}
+)
+
 const (
 	xhttpPlacementPath   = "path"
 	xhttpPlacementQuery  = "query"
@@ -157,7 +180,10 @@ func (ib *nativeInbound) serveXHTTPListener(ln net.Listener) {
 
 func (g *nativeXHTTPListener) serve(ln net.Listener) {
 	defer xrayRecover(fmt.Sprintf("native xray shared XHTTP listener addr=%s", ln.Addr()))
-	h2s := &http2.Server{}
+	h2s := &http2.Server{
+		IdleTimeout:          nativeXHTTPServerIdleTimeout,
+		MaxConcurrentStreams: nativeHTTP2MaxConcurrentStreams(),
+	}
 	handler := http.Handler(g)
 	// Official Xray accepts plaintext HTTP/1.1 and h2c on non-TLS XHTTP
 	// listeners, and negotiates h2/http1 through ALPN on TLS listeners. Without
@@ -169,6 +195,7 @@ func (g *nativeXHTTPListener) serve(ln net.Listener) {
 	srv := &http.Server{
 		Handler:           handler,
 		ReadHeaderTimeout: 4 * time.Second,
+		IdleTimeout:       nativeXHTTPServerIdleTimeout,
 		MaxHeaderBytes:    g.headerSize,
 	}
 	if g.security == "tls" && g.tlsConfig != nil {
@@ -258,6 +285,9 @@ func (ib *nativeInbound) reapStaleXHTTPSessions(idle time.Duration) {
 
 func (ib *nativeInbound) xhttpServerMaxHeaderBytes() int {
 	if ib.xhttpMaxHeaderBytes > 0 {
+		if ib.xhttpMaxHeaderBytes > nativeXHTTPHardMaxHeaderBytes {
+			return nativeXHTTPHardMaxHeaderBytes
+		}
 		return ib.xhttpMaxHeaderBytes
 	}
 	// Xray defaults to 8192. Keep a little room for custom headers/cookies used
@@ -269,19 +299,25 @@ func (ib *nativeInbound) xhttpServerMaxHeaderBytes() int {
 // byte stream to the VLESS/VMess handlers as a net.Conn.
 func (ib *nativeInbound) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	defer xrayRecover(fmt.Sprintf("native xray XHTTP request inbound=%q method=%s path=%q remote=%s", ib.tag, r.Method, r.URL.RequestURI(), r.RemoteAddr))
+	// XHTTP is a VPN transport, not a web API. A single connected user keeps a
+	// long-lived download handler and can generate many short packet-up handlers.
+	// Rejecting handlers at an application request ceiling turns normal tunnel
+	// bursts into 429s and, through CDNs/reverse proxies, intermittent 502s.
+	// HTTP/2 flow control plus the bounded, cancelable upload queues below provide
+	// backpressure without applying website rate-limit semantics to tunnel traffic.
 	if !ib.isXHTTP() {
-		xrayLogf("native xray: xhttp reject inbound=%q reason=not-xhttp method=%s path=%q host=%q remote=%s", ib.tag, r.Method, r.URL.RequestURI(), r.Host, r.RemoteAddr)
+		logNativePreAuthRejection("native xray: xhttp reject inbound=%q reason=not-xhttp method=%s path=%q host=%q remote=%s", ib.tag, r.Method, r.URL.RequestURI(), r.Host, r.RemoteAddr)
 		xhttpBadRequest(w)
 		return
 	}
 	if !ib.xhttpHostAllowed(r.Host) {
-		xrayLogf("native xray: xhttp reject inbound=%q reason=host method=%s path=%q host=%q want=%q remote=%s", ib.tag, r.Method, r.URL.RequestURI(), r.Host, ib.xhttpHost, r.RemoteAddr)
+		logNativePreAuthRejection("native xray: xhttp reject inbound=%q reason=host method=%s path=%q host=%q want=%q remote=%s", ib.tag, r.Method, r.URL.RequestURI(), r.Host, ib.xhttpHost, r.RemoteAddr)
 		w.WriteHeader(http.StatusNotFound)
 		return
 	}
 	base, ok := ib.matchXHTTPPath(r.URL.Path)
 	if !ok {
-		xrayLogf("native xray: xhttp reject inbound=%q reason=path method=%s path=%q want=%q host=%q remote=%s", ib.tag, r.Method, r.URL.RequestURI(), ib.path, r.Host, r.RemoteAddr)
+		logNativePreAuthRejection("native xray: xhttp reject inbound=%q reason=path method=%s path=%q want=%q host=%q remote=%s", ib.tag, r.Method, r.URL.RequestURI(), ib.path, r.Host, r.RemoteAddr)
 		w.WriteHeader(http.StatusNotFound)
 		return
 	}
@@ -293,6 +329,11 @@ func (ib *nativeInbound) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	sessionID, seqStr := ib.extractXHTTPMeta(r, base)
+	if len(sessionID) > nativeXHTTPMaxSessionIDBytes || len(seqStr) > nativeXHTTPMaxSequenceBytes {
+		logNativePreAuthRejection("native xray: xhttp reject inbound=%q reason=metadata-size remote=%s", ib.tag, r.RemoteAddr)
+		xhttpBadRequest(w)
+		return
+	}
 	mode := ib.normalizedXHTTPMode()
 	xrayTracef("native xray: xhttp request inbound=%q method=%s proto=%s path=%q host=%q session=%q seq=%q len=%d mode=%s remote=%s", ib.tag, r.Method, r.Proto, r.URL.RequestURI(), r.Host, sessionID, seqStr, r.ContentLength, mode, r.RemoteAddr)
 
@@ -520,17 +561,22 @@ func (ib *nativeInbound) upsertXHTTPSession(w http.ResponseWriter, id string) *n
 		return s
 	}
 	if max := ib.xhttpMaxActiveSessions(); max > 0 && len(ib.xhttpSessions) >= max {
-		// XHTTP uses many HTTP requests/sessions by design. Returning HTTP 429
-		// makes Xray clients tear down active tunnels, which is worse than allowing
-		// a short soft-limit overflow and relying on stale-session cleanup.
-		xrayTracef("native xray: xhttp session soft limit exceeded inbound=%q active=%d limit=%d", ib.tag, len(ib.xhttpSessions), max)
+		http.Error(w, "native XHTTP session capacity reached", http.StatusServiceUnavailable)
+		logNativePreAuthRejection("native xray: xhttp session rejected inbound=%q active=%d limit=%d", ib.tag, len(ib.xhttpSessions), max)
+		return nil
+	}
+	releaseSlot, ok := acquireNativeXHTTPSession()
+	if !ok {
+		http.Error(w, "native XHTTP global session capacity reached", http.StatusServiceUnavailable)
+		return nil
 	}
 	s := &nativeXHTTPSession{
 		id:          id,
-		queue:       newNativeXHTTPUploadQueue(ib.xhttpMaxBufferedPosts),
+		queue:       newNativeXHTTPUploadQueue(ib.xhttpMaxBufferedPosts, nativeXHTTPMaxBufferedSessionBytes),
 		done:        make(chan struct{}),
 		connectedCh: make(chan struct{}),
 		lastSeen:    time.Now(),
+		releaseSlot: releaseSlot,
 	}
 	ib.xhttpSessions[id] = s
 	xrayTracef("native xray: xhttp session created inbound=%q session=%q active=%d", ib.tag, id, len(ib.xhttpSessions))
@@ -539,10 +585,9 @@ func (ib *nativeInbound) upsertXHTTPSession(w http.ResponseWriter, id string) *n
 }
 
 func (ib *nativeInbound) xhttpMaxActiveSessions() int {
-	if nativeXHTTPMaxSessionLimit() > 0 {
-		return nativeXHTTPMaxSessionLimit()
-	}
-	return defaultNativeXHTTPMaxSessions
+	// normalizeNativeXrayTuning already installs the safe default. A zero value
+	// here therefore intentionally means the operator configured -1 (unlimited).
+	return nativeXHTTPMaxSessionLimit()
 }
 
 func (ib *nativeInbound) reapUnconnectedXHTTPSession(id string, s *nativeXHTTPSession) {
@@ -570,6 +615,19 @@ func (ib *nativeInbound) deleteXHTTPSession(id string, s *nativeXHTTPSession) {
 	}
 }
 
+func (ib *nativeInbound) closeAllXHTTPSessions() {
+	ib.xhttpMu.Lock()
+	sessions := make([]*nativeXHTTPSession, 0, len(ib.xhttpSessions))
+	for id, session := range ib.xhttpSessions {
+		delete(ib.xhttpSessions, id)
+		sessions = append(sessions, session)
+	}
+	ib.xhttpMu.Unlock()
+	for _, session := range sessions {
+		session.close()
+	}
+}
+
 func (ib *nativeInbound) handleXHTTPStreamUpload(w http.ResponseWriter, r *http.Request, sess *nativeXHTTPSession) {
 	sess.touch()
 	xrayTracef("native xray: xhttp stream-up inbound=%q session=%q len=%d remote=%s", ib.tag, sess.id, r.ContentLength, r.RemoteAddr)
@@ -577,7 +635,7 @@ func (ib *nativeInbound) handleXHTTPStreamUpload(w http.ResponseWriter, r *http.
 		http.Error(w, "xhttp stream-up mode is not allowed", http.StatusBadRequest)
 		return
 	}
-	if err := sess.queue.push(r.Context(), nativeXHTTPPacket{Reader: r.Body}); err != nil {
+	if err := sess.queue.push(r.Context(), nativeXHTTPPacket{Reader: r.Body}, nil); err != nil {
 		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 			return
 		}
@@ -605,16 +663,38 @@ func (ib *nativeInbound) handleXHTTPPacketUpload(w http.ResponseWriter, r *http.
 		http.Error(w, "bad xhttp sequence", http.StatusBadRequest)
 		return
 	}
+	// Reserve the expected payload rather than the configured maximum. Normal
+	// XHTTP body uploads have a Content-Length, so small packets no longer each
+	// consume a full 1 MB reservation. Unknown/chunked or metadata-carried uploads
+	// still reserve the maximum before decoding to preserve the hard memory bound.
+	memory, err := acquireNativeXHTTPMemoryContext(r.Context(), ib.xhttpUploadReservationBytes(r))
+	if err != nil {
+		// If the client/CDN canceled while waiting for backpressure, there is no
+		// useful HTTP error to send. Returning also releases every reservation.
+		return
+	}
+	defer memory.release()
 	payload, err := ib.readXHTTPPayload(r)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
+	memory.shrink(int64(len(payload)))
 	xrayTracef("native xray: xhttp packet-up inbound=%q session=%q seq=%d payload=%d remote=%s", ib.tag, sess.id, seq, len(payload), r.RemoteAddr)
-	if err := sess.queue.push(r.Context(), nativeXHTTPPacket{Payload: payload, Seq: seq}); err != nil {
+	if err := sess.queue.push(r.Context(), nativeXHTTPPacket{Payload: payload, Seq: seq}, memory); err != nil {
 		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
 			return
 		}
+		if errors.Is(err, io.ErrClosedPipe) {
+			// A packet can race the stream-down request closing. Acknowledge the late
+			// upload instead of leaking an origin 500/502 into the reconnect path.
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+		if errors.Is(err, errNativeXHTTPUploadBufferFull) {
+			http.Error(w, err.Error(), http.StatusRequestEntityTooLarge)
+			return
+		}
 		xrayTracef("native xray: xhttp packet-up push failed inbound=%q session=%q seq=%d: %v", ib.tag, sess.id, seq, err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
@@ -719,11 +799,30 @@ func (ib *nativeInbound) readXHTTPBodyPayload(r *http.Request) ([]byte, error) {
 
 func (ib *nativeInbound) xhttpMaxPostBytes() int64 {
 	if ib.xhttpMaxEachPostBytes > 0 {
+		if ib.xhttpMaxEachPostBytes > nativeXHTTPHardMaxPostBytes {
+			return nativeXHTTPHardMaxPostBytes
+		}
 		return ib.xhttpMaxEachPostBytes
 	}
 	return 1_000_000
 }
 
+// xhttpUploadReservationBytes returns a safe pre-read reservation. Body-mode
+// clients normally send Content-Length, which lets thousands of small packets
+// share the global budget. Header/cookie/auto and chunked bodies reserve the
+// configured maximum because their decoded size is not known until parsed.
+func (ib *nativeInbound) xhttpUploadReservationBytes(r *http.Request) int64 {
+	maxBytes := ib.xhttpMaxPostBytes()
+	placement := firstNonEmpty(ib.xhttpUplinkDataPlacement, xhttpPlacementBody)
+	if placement == xhttpPlacementBody && r.ContentLength >= 0 {
+		if r.ContentLength > maxBytes {
+			return maxBytes
+		}
+		return r.ContentLength
+	}
+	return maxBytes
+}
+
 func (ib *nativeInbound) handleXHTTPStreamOne(w http.ResponseWriter, r *http.Request) {
 	defer xrayRecover(fmt.Sprintf("native xray XHTTP stream-one inbound=%q remote=%s", ib.tag, r.RemoteAddr))
 	xrayTracef("native xray: xhttp stream-one inbound=%q len=%d remote=%s", ib.tag, r.ContentLength, r.RemoteAddr)
@@ -794,7 +893,7 @@ func (ib *nativeInbound) handleXHTTPDownload(w http.ResponseWriter, r *http.Requ
 			// The stream-down HTTP request is the lifetime owner of an XHTTP
 			// session. Log the actual transport cancellation so a CDN/proxy
 			// timeout can be distinguished from a server idle policy.
-			xrayLogf("native xray: xhttp stream-down ended inbound=%q session=%q remote=%s err=%v",
+			xrayTracef("native xray: xhttp stream-down ended inbound=%q session=%q remote=%s err=%v",
 				ib.tag, sessionID, r.RemoteAddr, r.Context().Err())
 			_ = xc.Close()
 		case <-sess.done:
@@ -859,6 +958,7 @@ type nativeXHTTPSession struct {
 	mu          sync.Mutex
 	connected   bool
 	lastSeen    time.Time
+	releaseSlot func()
 }
 
 func (s *nativeXHTTPSession) touch() {
@@ -879,6 +979,9 @@ func (s *nativeXHTTPSession) close() {
 	s.closeOnce.Do(func() {
 		close(s.done)
 		s.queue.close()
+		if s.releaseSlot != nil {
+			s.releaseSlot()
+		}
 	})
 }
 
@@ -980,6 +1083,108 @@ func (w *nativeXHTTPResponseWriter) close() {
 	w.mu.Unlock()
 }
 
+// nativeXHTTPMemoryLease reserves from a process-wide byte budget before a
+// packet-up handler allocates its payload. The same lease is transferred to the
+// session queue, so active request bodies and queued reassembly data share one
+// hard ceiling instead of each having an independent amplification window.
+type nativeXHTTPMemoryLease struct {
+	bytes int64
+}
+
+func acquireNativeXHTTPMemory(n int64) (*nativeXHTTPMemoryLease, bool) {
+	if n <= 0 {
+		return &nativeXHTTPMemoryLease{}, true
+	}
+	for {
+		current := nativeXHTTPBufferedBytes.Load()
+		if current > nativeXHTTPMaxBufferedGlobalBytes-n {
+			logNativeLimitRejection("XHTTP buffered upload bytes", &nativeXHTTPBufferRejected, nativeXHTTPMaxBufferedGlobalBytes)
+			return nil, false
+		}
+		if nativeXHTTPBufferedBytes.CompareAndSwap(current, current+n) {
+			return &nativeXHTTPMemoryLease{bytes: n}, true
+		}
+	}
+}
+
+// acquireNativeXHTTPMemoryContext applies process-wide memory backpressure.
+// Unlike the old fail-fast admission path, a legitimate tunnel burst waits for
+// queued bytes to be consumed and remains cancelable if its HTTP request ends.
+func acquireNativeXHTTPMemoryContext(ctx context.Context, n int64) (*nativeXHTTPMemoryLease, error) {
+	if n <= 0 {
+		return &nativeXHTTPMemoryLease{}, nil
+	}
+	if n > nativeXHTTPMaxBufferedGlobalBytes {
+		return nil, errNativeXHTTPUploadBufferFull
+	}
+	for {
+		current := nativeXHTTPBufferedBytes.Load()
+		if current <= nativeXHTTPMaxBufferedGlobalBytes-n && nativeXHTTPBufferedBytes.CompareAndSwap(current, current+n) {
+			return &nativeXHTTPMemoryLease{bytes: n}, nil
+		}
+
+		nativeXHTTPMemoryWait.Lock()
+		// Recheck while holding the generation lock so a release cannot happen
+		// between the failed check and subscribing to the notification channel.
+		current = nativeXHTTPBufferedBytes.Load()
+		if current <= nativeXHTTPMaxBufferedGlobalBytes-n {
+			nativeXHTTPMemoryWait.Unlock()
+			continue
+		}
+		changed := nativeXHTTPMemoryWait.changed
+		nativeXHTTPMemoryWait.Unlock()
+		select {
+		case <-changed:
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		}
+	}
+}
+
+func releaseNativeXHTTPMemory(n int64) {
+	if n <= 0 {
+		return
+	}
+	for {
+		current := nativeXHTTPBufferedBytes.Load()
+		next := current - n
+		if next < 0 {
+			next = 0
+		}
+		if nativeXHTTPBufferedBytes.CompareAndSwap(current, next) {
+			nativeXHTTPMemoryWait.Lock()
+			close(nativeXHTTPMemoryWait.changed)
+			nativeXHTTPMemoryWait.changed = make(chan struct{})
+			nativeXHTTPMemoryWait.Unlock()
+			return
+		}
+	}
+}
+
+func (l *nativeXHTTPMemoryLease) shrink(n int64) {
+	if l == nil {
+		return
+	}
+	if n < 0 {
+		n = 0
+	}
+	if n >= l.bytes {
+		return
+	}
+	release := l.bytes - n
+	l.bytes = n
+	releaseNativeXHTTPMemory(release)
+}
+
+func (l *nativeXHTTPMemoryLease) release() {
+	if l == nil || l.bytes <= 0 {
+		return
+	}
+	n := l.bytes
+	l.bytes = 0
+	releaseNativeXHTTPMemory(n)
+}
+
 type nativeXHTTPPacket struct {
 	Reader  io.ReadCloser
 	Payload []byte
@@ -989,44 +1194,148 @@ type nativeXHTTPPacket struct {
 type nativeXHTTPUploadQueue struct {
 	pushedPackets chan nativeXHTTPPacket
 	maxPackets    int
+	maxBytes      int64
 
-	mu           sync.Mutex
-	reader       io.ReadCloser
-	heap         nativeXHTTPHeap
-	nextSeq      uint64
-	readDeadline time.Time
+	// readMu serializes the single decoded stream reader with close-time queue
+	// cleanup. pushWG lets close wait until every producer that started before
+	// closedFlag was set has either transferred or released its memory lease.
+	readMu        sync.Mutex
+	pushWG        sync.WaitGroup
+	mu            sync.Mutex
+	reader        io.ReadCloser
+	readerQueued  bool
+	heap          nativeXHTTPHeap
+	nextSeq       uint64
+	readDeadline  time.Time
+	bufferedBytes int64
+	closedFlag    bool
+	spaceChanged  chan struct{}
 
 	closed    chan struct{}
 	closeOnce sync.Once
 }
 
-func newNativeXHTTPUploadQueue(maxPackets int) *nativeXHTTPUploadQueue {
+func newNativeXHTTPUploadQueue(maxPackets int, maxBytes int64) *nativeXHTTPUploadQueue {
 	if maxPackets <= 0 {
 		maxPackets = defaultNativeXHTTPBufferedPosts
 	}
+	if maxPackets > nativeXHTTPMaxBufferedPosts {
+		maxPackets = nativeXHTTPMaxBufferedPosts
+	}
+	if maxBytes <= 0 || maxBytes > nativeXHTTPMaxBufferedSessionBytes {
+		maxBytes = nativeXHTTPMaxBufferedSessionBytes
+	}
 	return &nativeXHTTPUploadQueue{
 		pushedPackets: make(chan nativeXHTTPPacket, maxPackets),
 		maxPackets:    maxPackets,
+		maxBytes:      maxBytes,
 		closed:        make(chan struct{}),
+		spaceChanged:  make(chan struct{}),
 	}
 }
 
-func (q *nativeXHTTPUploadQueue) push(ctx context.Context, p nativeXHTTPPacket) error {
+func (q *nativeXHTTPUploadQueue) beginPush() bool {
+	q.mu.Lock()
+	defer q.mu.Unlock()
+	if q.closedFlag {
+		return false
+	}
+	q.pushWG.Add(1)
+	return true
+}
+
+func (q *nativeXHTTPUploadQueue) adoptPayloadMemory(ctx context.Context, memory *nativeXHTTPMemoryLease, n int64) error {
+	if n <= 0 {
+		return nil
+	}
+	if memory == nil || memory.bytes != n {
+		return errNativeXHTTPUploadBufferFull
+	}
+	if n > q.maxBytes {
+		return errNativeXHTTPUploadBufferFull
+	}
+	for {
+		q.mu.Lock()
+		if q.closedFlag {
+			q.mu.Unlock()
+			return io.ErrClosedPipe
+		}
+		if q.bufferedBytes <= q.maxBytes-n {
+			q.bufferedBytes += n
+			memory.bytes = 0
+			q.mu.Unlock()
+			return nil
+		}
+		changed := q.spaceChanged
+		q.mu.Unlock()
+		select {
+		case <-changed:
+		case <-q.closed:
+			return io.ErrClosedPipe
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+}
+
+func (q *nativeXHTTPUploadQueue) releasePayloadMemory(n int64) {
+	if n <= 0 {
+		return
+	}
+	q.mu.Lock()
+	release := n
+	if release > q.bufferedBytes {
+		release = q.bufferedBytes
+	}
+	q.bufferedBytes -= release
+	close(q.spaceChanged)
+	q.spaceChanged = make(chan struct{})
+	q.mu.Unlock()
+	releaseNativeXHTTPMemory(release)
+}
+
+func (q *nativeXHTTPUploadQueue) push(ctx context.Context, p nativeXHTTPPacket, memory *nativeXHTTPMemoryLease) error {
+	if !q.beginPush() {
+		return io.ErrClosedPipe
+	}
+	defer q.pushWG.Done()
+
+	readerReserved := false
 	if p.Reader != nil {
 		q.mu.Lock()
-		if q.reader != nil {
+		if q.reader != nil || q.readerQueued || q.closedFlag {
 			q.mu.Unlock()
 			return errors.New("xhttp upload reader already exists")
 		}
+		q.readerQueued = true
+		readerReserved = true
 		q.mu.Unlock()
+		defer func() {
+			if readerReserved {
+				q.mu.Lock()
+				q.readerQueued = false
+				q.mu.Unlock()
+			}
+		}()
+	}
+	payloadBytes := int64(len(p.Payload))
+	if err := q.adoptPayloadMemory(ctx, memory, payloadBytes); err != nil {
+		return err
+	}
+	transferred := payloadBytes > 0
+	if transferred {
+		defer func() {
+			if payloadBytes > 0 {
+				q.releasePayloadMemory(payloadBytes)
+			}
+		}()
 	}
 	select {
 	case q.pushedPackets <- p:
-		select {
-		case <-q.closed:
-			return io.ErrClosedPipe
-		default:
-		}
+		// Ownership has moved to the queue. close() waits for this producer and
+		// then drains/releases anything not consumed by the stream reader.
+		payloadBytes = 0
+		readerReserved = false
 		return nil
 	case <-q.closed:
 		return io.ErrClosedPipe
@@ -1037,13 +1346,41 @@ func (q *nativeXHTTPUploadQueue) push(ctx context.Context, p nativeXHTTPPacket)
 
 func (q *nativeXHTTPUploadQueue) close() {
 	q.closeOnce.Do(func() {
-		close(q.closed)
 		q.mu.Lock()
+		q.closedFlag = true
 		reader := q.reader
+		close(q.closed)
 		q.mu.Unlock()
 		if reader != nil {
 			_ = reader.Close()
 		}
+
+		q.pushWG.Wait()
+		q.readMu.Lock()
+		// No producers or readers can now change the queue. Drop references to
+		// buffered payloads promptly and return their exact byte reservation.
+		for {
+			select {
+			case p := <-q.pushedPackets:
+				if p.Reader != nil {
+					_ = p.Reader.Close()
+				}
+				p.Payload = nil
+			default:
+				goto drained
+			}
+		}
+	drained:
+		q.mu.Lock()
+		remaining := q.bufferedBytes
+		q.bufferedBytes = 0
+		for i := range q.heap {
+			q.heap[i].Payload = nil
+		}
+		q.heap = nil
+		q.mu.Unlock()
+		q.readMu.Unlock()
+		releaseNativeXHTTPMemory(remaining)
 	})
 }
 
@@ -1085,6 +1422,9 @@ func (q *nativeXHTTPUploadQueue) recv() (nativeXHTTPPacket, error) {
 }
 
 func (q *nativeXHTTPUploadQueue) Read(b []byte) (int, error) {
+	q.readMu.Lock()
+	defer q.readMu.Unlock()
+
 	if reader := q.loadReader(); reader != nil {
 		return reader.Read(b)
 	}
@@ -1101,9 +1441,18 @@ func (q *nativeXHTTPUploadQueue) Read(b []byte) (int, error) {
 			return 0, err
 		}
 		if p.Reader != nil {
-			q.setReader(p.Reader)
+			if !q.setReader(p.Reader) {
+				_ = p.Reader.Close()
+				return 0, io.EOF
+			}
 			return p.Reader.Read(b)
 		}
+		select {
+		case <-q.closed:
+			q.releasePayloadMemory(int64(len(p.Payload)))
+			return 0, io.EOF
+		default:
+		}
 		heap.Push(&q.heap, p)
 	}
 
@@ -1112,6 +1461,7 @@ func (q *nativeXHTTPUploadQueue) Read(b []byte) (int, error) {
 
 		if packet.Seq == q.nextSeq {
 			n := copy(b, packet.Payload)
+			q.releasePayloadMemory(int64(n))
 			if n < len(packet.Payload) {
 				packet.Payload = packet.Payload[n:]
 				heap.Push(&q.heap, packet)
@@ -1131,10 +1481,15 @@ func (q *nativeXHTTPUploadQueue) Read(b []byte) (int, error) {
 				return 0, err
 			}
 			if p.Reader != nil {
+				_ = p.Reader.Close()
 				return 0, errors.New("xhttp mixed stream-up and packet-up upload")
 			}
 			heap.Push(&q.heap, p)
+			continue
 		}
+
+		// A duplicate/late packet is discarded; release the bytes it owned.
+		q.releasePayloadMemory(int64(len(packet.Payload)))
 	}
 
 	return 0, nil
@@ -1146,10 +1501,14 @@ func (q *nativeXHTTPUploadQueue) loadReader() io.ReadCloser {
 	return q.reader
 }
 
-func (q *nativeXHTTPUploadQueue) setReader(r io.ReadCloser) {
+func (q *nativeXHTTPUploadQueue) setReader(r io.ReadCloser) bool {
 	q.mu.Lock()
+	defer q.mu.Unlock()
+	if q.closedFlag {
+		return false
+	}
 	q.reader = r
-	q.mu.Unlock()
+	return true
 }
 
 type nativeXHTTPHeap []nativeXHTTPPacket