fixed server go

2026-05-08 14:33:23 +00:00 · 2026-05-07 22:30:18 +03:00
parent c877e1e5cb
commit f65fd4a8c5
10 changed files with 365 additions and 32 deletions
--- a/client/CMakeLists.txt
+++ b/client/CMakeLists.txt
@@ -214,6 +214,14 @@ if(AMNEZIA_QR_PAIRING_ALLOW_DUPLICATE_VPN_KEY)
    target_compile_definitions(${PROJECT} PRIVATE AMNEZIA_QR_PAIRING_ALLOW_DUPLICATE_VPN_KEY)
 endif()

+option(AMNEZIA_LAN_PLAINTEXT_GATEWAY "Dev: plaintext JSON to private LAN gateway hosts (requires AMNEZIA_QR_PAIRING_ALLOW)" OFF)
+if(AMNEZIA_LAN_PLAINTEXT_GATEWAY)
+    if(NOT AMNEZIA_QR_PAIRING_ALLOW)
+        message(FATAL_ERROR "AMNEZIA_LAN_PLAINTEXT_GATEWAY=ON requires AMNEZIA_QR_PAIRING_ALLOW=ON")
+    endif()
+    target_compile_definitions(${PROJECT} PRIVATE AMNEZIA_LAN_PLAINTEXT_GATEWAY)
+endif()
+
 target_sources(${PROJECT} PRIVATE ${SOURCES} ${HEADERS} ${RESOURCES} ${QRC} ${I18NQRC})

 # Finalize the executable so Qt can gather/deploy QML modules and plugins correctly (Android needs this).
--- a/client/core/controllers/api/pairingController.cpp
+++ b/client/core/controllers/api/pairingController.cpp
@@ -2,12 +2,14 @@

 #include <QJsonDocument>
 #include <QSysInfo>
+#include <QUrl>

 #include "core/controllers/gatewayController.h"
 #include "core/repositories/secureAppSettingsRepository.h"
 #include "core/utils/api/apiUtils.h"
 #include "core/utils/constants/apiConstants.h"
 #include "core/utils/constants/apiKeys.h"
+#include "core/utils/networkUtilities.h"
 #include "version.h"

 using namespace amnezia;
@@ -22,10 +24,18 @@ constexpr qsizetype kPairingMaxApiKeyChars = 8192;

 bool isLocalGatewayHost(const QString &gatewayUrl)
 {
-    return gatewayUrl.contains(QStringLiteral("127.0.0.1"), Qt::CaseInsensitive)
-            || gatewayUrl.contains(QStringLiteral("localhost"), Qt::CaseInsensitive)
-            || gatewayUrl.contains(QStringLiteral("[::1]"), Qt::CaseInsensitive)
-            || gatewayUrl.contains(QStringLiteral("::1"), Qt::CaseInsensitive);
+    if (gatewayUrl.contains(QStringLiteral("127.0.0.1"), Qt::CaseInsensitive)
+        || gatewayUrl.contains(QStringLiteral("localhost"), Qt::CaseInsensitive)
+        || gatewayUrl.contains(QStringLiteral("[::1]"), Qt::CaseInsensitive)
+        || gatewayUrl.contains(QStringLiteral("::1"), Qt::CaseInsensitive)) {
+        return true;
+    }
+#ifdef AMNEZIA_LAN_PLAINTEXT_GATEWAY
+    const QUrl u(gatewayUrl);
+    return NetworkUtilities::hostIsPrivateLanAddress(u.host());
+#else
+    return false;
+#endif
 }

 ErrorCode applyGatewayOrOpenApiGenerateError(const QJsonObject &obj, PairingController::QrPairingConfigPayload &outPayload)
--- a/client/core/controllers/gatewayController.cpp
+++ b/client/core/controllers/gatewayController.cpp
@@ -94,7 +94,13 @@ GatewayController::EncryptedRequestData GatewayController::prepareRequest(const
    {
        const QUrl gatewayUrl(m_proxyUrl.isEmpty() ? m_gatewayEndpoint : m_proxyUrl);
        const QString host = gatewayUrl.host().toLower();
-        if (host == QLatin1String("localhost") || host == QLatin1String("127.0.0.1") || host == QLatin1String("::1")) {
+        bool usePlaintext = (host == QLatin1String("localhost") || host == QLatin1String("127.0.0.1") || host == QLatin1String("::1"));
+#ifdef AMNEZIA_LAN_PLAINTEXT_GATEWAY
+        if (!usePlaintext) {
+            usePlaintext = NetworkUtilities::hostIsPrivateLanAddress(host);
+        }
+#endif
+        if (usePlaintext) {
            encRequestData.isPlaintextLocalGateway = true;
            encRequestData.requestBody = QJsonDocument(apiPayload).toJson();
            return encRequestData;
--- a/client/core/repositories/secureAppSettingsRepository.cpp
+++ b/client/core/repositories/secureAppSettingsRepository.cpp
@@ -3,6 +3,7 @@
 #include <QJsonDocument>
 #include <QJsonArray>
 #include <QUuid>
+#include <QUrl>

 #include "core/utils/errorCodes.h"
 #include "core/utils/routeModes.h"
@@ -260,6 +261,14 @@ QString SecureAppSettingsRepository::getGatewayEndpoint(bool isTestPurchase) con
            || base.contains(QStringLiteral("[::1]"), Qt::CaseInsensitive)) {
            return m_gatewayEndpoint;
        }
+#ifdef AMNEZIA_LAN_PLAINTEXT_GATEWAY
+        {
+            const QUrl gatewayUrl(base);
+            if (NetworkUtilities::hostIsPrivateLanAddress(gatewayUrl.host())) {
+                return m_gatewayEndpoint;
+            }
+        }
+#endif
        return QString(DEV_AGW_ENDPOINT);
    }
    return m_gatewayEndpoint;
--- a/client/core/utils/networkUtilities.cpp
+++ b/client/core/utils/networkUtilities.cpp
@@ -42,6 +42,7 @@
    #include <net/if.h>
 #endif

+#include <QAbstractSocket>
 #include <QHostAddress>
 #include <QHostInfo>

@@ -491,3 +492,25 @@ QPair<QString, QNetworkInterface> NetworkUtilities::getGatewayAndIface()
    return { gateway, QNetworkInterface::interfaceFromIndex(index) };
 #endif
 }
+
+bool NetworkUtilities::hostIsPrivateLanAddress(const QString &host)
+{
+    if (host.isEmpty()) {
+        return false;
+    }
+    QHostAddress addr(host);
+    if (addr.isNull() || addr.isLoopback()) {
+        return false;
+    }
+    if (addr.protocol() == QAbstractSocket::IPv4Protocol) {
+        return addr.isInSubnet(QHostAddress(QStringLiteral("10.0.0.0")), 8)
+                || addr.isInSubnet(QHostAddress(QStringLiteral("172.16.0.0")), 12)
+                || addr.isInSubnet(QHostAddress(QStringLiteral("192.168.0.0")), 16)
+                || addr.isInSubnet(QHostAddress(QStringLiteral("169.254.0.0")), 16);
+    }
+    if (addr.protocol() == QAbstractSocket::IPv6Protocol) {
+        return addr.isInSubnet(QHostAddress(QStringLiteral("fe80::")), 10)
+                || addr.isInSubnet(QHostAddress(QStringLiteral("fc00::")), 7);
+    }
+    return false;
+}
--- a/client/core/utils/networkUtilities.h
+++ b/client/core/utils/networkUtilities.h
@@ -30,6 +30,9 @@ public:
    static QString netMaskFromIpWithSubnet(const QString ip);
    static QString ipAddressFromIpWithSubnet(const QString ip);
    static QStringList summarizeRoutes(const QStringList &ips, const QString cidr);
+
+    /// True for RFC1918 / IPv4 link-local / IPv6 ULA or IPv6 link-local (dev-only LAN gateway with tools/local_gateway).
+    static bool hostIsPrivateLanAddress(const QString &host);
 };

 #endif // NETWORKUTILITIES_H
--- a/tools/local_gateway/LAN_GATEWAY.md
+++ b/tools/local_gateway/LAN_GATEWAY.md
@@ -0,0 +1,77 @@
+# Local gateway: LAN / Wi‑Fi (macOS host ↔ iOS client)
+
+This document is the **implementation checklist** for `tools/local_gateway` plus the **AmneziaVPN client** dev flags used with a **plaintext** mock over **private LAN** addresses (not only `127.0.0.1`).
+
+## Goals
+
+1. Run **`tools/local_gateway`** on a Mac; reach it from an iPhone on the same Wi‑Fi via **`http://<mac-lan-ip>:<port>/`**.
+2. **`POST /v1/updater_endpoint`** must return a **`url`** the phone can reach (not `http://127.0.0.1:8080`, which points at the phone itself).
+3. **Verbose logs** on the server for debugging.
+4. **Client:** plaintext JSON to the mock only for **loopback** by default; **optional** plaintext to **RFC1918 / ULA / link-local** hosts when **`AMNEZIA_LAN_PLAINTEXT_GATEWAY=ON`** (requires **`AMNEZIA_QR_PAIRING_ALLOW=ON`**).
+
+> **Security:** `AMNEZIA_LAN_PLAINTEXT_GATEWAY` disables transport encryption to any configured gateway whose host parses as a private LAN address. Use **only** in internal dev builds with `tools/local_gateway`, never for production endpoints.
+
+---
+
+## Phase A — Go server (`main.go`)
+
+| Item | Status |
+|------|--------|
+| **`-listen` / `LOCAL_GATEWAY_LISTEN`** | Default `0.0.0.0:8080`; append `:8080` if port omitted. Still **`tcp4`** only (macOS LAN / curl oddities). |
+| **`-public-base` / `LOCAL_GATEWAY_PUBLIC_BASE`** | Base URL **without** trailing slash; fed into **`POST /v1/updater_endpoint`** as `{"url":…}`. |
+| **`-auto-public`** (default true) | If `public-base` empty, pick first **non-loopback IPv4** (prefers **private** / link-local over public). |
+| **`-pairing-ttl` / `-long-poll` / `-rate-limit-excess-after`** | Replace hardcoded **120s** / **120s** / **0** for pairing and Free mock. |
+| **Startup banner** | Logs listen address, chosen **`publicUpdaterBaseURL`**, and **every** `http://<ipv4>:port/` candidate per interface. |
+| **Request logging** | `REQ start` (remote, method, path, query, UA, `X-Client-Request-ID`, content type/length) + `REQ end` (status, duration). |
+| **Pairing logs** | Extra fields on register/complete (`installation_uuid` short, app/os, `config_len`, protocol count). |
+
+### Example: Mac + iPhone
+
+```bash
+cd tools/local_gateway
+# Explicit base (safest if you have several NICs):
+LOCAL_GATEWAY_PUBLIC_BASE='http://192.168.1.10:8080' go run -buildvcs=false .
+
+# Or rely on auto-public (first suitable IPv4 + listen port):
+go run -buildvcs=false .
+```
+
+Firewall: allow incoming TCP on the chosen port (e.g. **8080**) for **local subnet**.
+
+---
+
+## Phase B — Client (CMake + C++)
+
+| CMake | Meaning |
+|-------|---------|
+| **`AMNEZIA_QR_PAIRING_ALLOW=ON`** | Enables QR pairing + **loopback** plaintext to `localhost` / `127.0.0.1` / `::1` (`GatewayController`). |
+| **`AMNEZIA_LAN_PLAINTEXT_GATEWAY=ON`** | **Also** sends plaintext JSON when gateway host is **private LAN** per `NetworkUtilities::hostIsPrivateLanAddress` (IPv4: `10/8`, `172.16/12`, `192.168/16`, `169.254/16`; IPv6: `fe80::/10`, `fc00::/7`). **Requires** `AMNEZIA_QR_PAIRING_ALLOW=ON` or CMake **fatal error**. |
+
+| Code | Change |
+|------|--------|
+| `NetworkUtilities::hostIsPrivateLanAddress` | Shared predicate for gateway + pairing + sandbox endpoint retention. |
+| `GatewayController::prepareRequest` | Plaintext path for LAN when `AMNEZIA_LAN_PLAINTEXT_GATEWAY` is defined. |
+| `PairingController::isLocalGatewayHost` | Treats LAN like mock for **120s** long-poll alignment with `tools/local_gateway`. |
+| `SecureAppSettingsRepository::getGatewayEndpoint(true)` | Keeps user’s LAN mock URL under **test purchase** (same idea as loopback). |
+
+Configure iOS dev build with both options, set gateway in app to **`http://<mac-ip>:8080/`** (trailing slash as today).
+
+---
+
+## Phase C — Smoke test
+
+```bash
+cd tools/local_gateway
+go run -buildvcs=false . &
+sleep 1
+bash verify.sh 'http://127.0.0.1:8080'
+# or against LAN IP from another shell on same machine:
+bash verify.sh 'http://192.168.1.10:8080'
+```
+
+---
+
+## References
+
+- `tools/local_gateway/README.md` — quick start and endpoint table.
+- `docs/local-gateway-mock.md` — client wiring and checklist.
--- a/tools/local_gateway/README.md
+++ b/tools/local_gateway/README.md
@@ -13,16 +13,32 @@
 ```bash
 cd tools/local_gateway
 go mod download
-go run .
+go run -buildvcs=false .
 ```

-Сервер слушает **`0.0.0.0:8080`** (все IPv4‑интерфейсы): с этого Mac — `http://127.0.0.1:8080/`, с телефона в той же LAN — `http://<IP-это-машины>:8080/`.
+По умолчанию слушает **`0.0.0.0:8080`** (**`tcp4`** только — см. ниже). С Mac: `http://127.0.0.1:8080/`; с телефона в той же Wi‑Fi: `http://<LAN-IP-Mac>:8080/`.

-Сервер поднимается через **`net.Listen("tcp4", "0.0.0.0:8080")`**, чтобы на macOS не ловить пустой ответ при `curl`/браузере на **LAN‑IP** (частая нестыковка IPv4/IPv6 у `ListenAndServe(":8080", …)`).
+**Флаги и переменные окружения** (полный чеклист: **[LAN_GATEWAY.md](./LAN_GATEWAY.md)**):

-После `git pull` обязательно **остановите старый процесс** на 8080 (`Ctrl+C` в терминале или `kill <PID>`), иначе будет крутиться бинарник без правок.
+| Флаг / env | Назначение |
+|------------|------------|
+| `-listen` / `LOCAL_GATEWAY_LISTEN` | Адрес привязки, например `0.0.0.0:8080` (порт можно опустить — подставится `:8080`). |
+| `-public-base` / `LOCAL_GATEWAY_PUBLIC_BASE` | Базовый URL **без** хвостового `/` для тела **`POST /v1/updater_endpoint`** (`url`). Нужен для **iOS по LAN** (иначе `127.0.0.1` указывает на сам телефон). |
+| `-auto-public` (по умолчанию `true`) | Если `public-base` пуст, взять первый подходящий **не loopback** IPv4 и собрать `http://IP:порт`. |
+| `-pairing-ttl`, `-long-poll` | TTL сессии QR и long-poll (по умолчанию **120s**, как раньше). |
+| `-rate-limit-excess-after` | Порог для мока Amnezia Free / CAPTCHA (по умолчанию **0**). |

-В логах при старте: `plaintext mock on tcp4 0.0.0.0:8080 — see ... README.md for paths`. Каждый запрос дополнительно пишется как `REQ <METHOD> <path>`.
+Пример для iPhone + Mac:
+
+```bash
+LOCAL_GATEWAY_PUBLIC_BASE='http://192.168.1.10:8080' go run -buildvcs=false .
+```
+
+`net.Listen("tcp4", …)` оставлен, чтобы на macOS не ловить пустой ответ при `curl`/браузере на **LAN‑IPv4** (частая нестыковка IPv4/IPv6 у `ListenAndServe(":8080", …)`).
+
+После `git pull` обязательно **остановите старый процесс** на порту (`Ctrl+C` или `kill <PID>`).
+
+**Логи:** при старте печатается баннер с **`updater_endpoint` URL** и списком **`http://<ipv4>:порт/`** по интерфейсам. Каждый запрос: строки **`REQ start`** (remote addr, path, UA, `X-Client-Request-ID`, размер тела) и **`REQ end`** (HTTP status, длительность).

 Проверка без клиента (mock должен быть запущен):

@@ -45,7 +61,7 @@ bash verify.sh http://127.0.0.1:8080
 | `POST` | `/v1/config` | Amnezia Free: CAPTCHA/лимит; иначе короткий мок‑ответ (полноценный premium `vpn://` здесь не строится). |
 | `POST` | `/v1/news` | Лента новостей (`NewsController`), пустой `news`. |
 | `POST` | `/v1/renewal_link` | Ссылка продления (`renewal_url`). |
-| `POST` | `/v1/updater_endpoint` | `{"url":"http://127.0.0.1:8080"}` → затем GET `/VERSION` на этом хосте. |
+| `POST` | `/v1/updater_endpoint` | `{"url":"…"}` — база из **`-public-base` / `LOCAL_GATEWAY_PUBLIC_BASE`** или **`-auto-public`**; затем клиент делает GET `/VERSION` на этом хосте. |
 | `POST` | `/v1/revoke_config` | Успех, тело не разбирается при `NoError`. |
 | `POST` | `/v1/revoke_native_config` | То же. |
 | `POST` | `/api/v1/generate_qr` | Pairing: long-poll (**120s** mock). |
@@ -57,8 +73,9 @@ bash verify.sh http://127.0.0.1:8080

 ## Связка с клиентом AmneziaVPN

-1. Соберите клиент с определением **`AMNEZIA_LOCAL_GATEWAY`** (см. `client/CMakeLists.txt`, `target_compile_definitions`) — тогда для **`127.0.0.1`** и **`localhost`** запросы к gateway уходят **plaintext JSON** без RSA/AES (см. `GatewayController`, `SecureAppSettingsRepository`).
-2. В настройках приложения endpoint gateway: **`http://127.0.0.1:8080/`** (дефолт при `AMNEZIA_LOCAL_GATEWAY` в коде). Допустим и `http://localhost:8080/` — тоже plaintext.
+1. Включите **`AMNEZIA_QR_PAIRING_ALLOW=ON`** в CMake — тогда для **`127.0.0.1`**, **`localhost`**, **`::1`** запросы к gateway идут **plaintext JSON** без RSA/AES (`GatewayController`).
+2. Для **iOS / другого хоста по LAN-IP** (`192.168.x.x` и т.п.) дополнительно включите **`AMNEZIA_LAN_PLAINTEXT_GATEWAY=ON`** (требует `AMNEZIA_QR_PAIRING_ALLOW`). Иначе клиент шифрует тело как к прод gateway, mock его не поймёт. Подробности: **[LAN_GATEWAY.md](./LAN_GATEWAY.md)**.
+3. В настройках приложения укажите endpoint: **`http://127.0.0.1:8080/`** или **`http://<LAN-IP>:8080/`** (с завершающим `/`, как принято в репозитории).

 Пошаговый план (включая следующие этапы вроде `/v1/account_info`): **`docs/local-gateway-mock.md`**.

--- a/tools/local_gateway/main.go
+++ b/tools/local_gateway/main.go
@@ -1,4 +1,4 @@
-// Plaintext mock for AmneziaVPN client (CMake AMNEZIA_LOCAL_GATEWAY=ON + localhost DEV_AGW_ENDPOINT).
+// Plaintext mock for AmneziaVPN client (CMake AMNEZIA_QR_PAIRING_ALLOW; optional AMNEZIA_LAN_PLAINTEXT_GATEWAY for RFC1918 hosts).
 // No RSA/AES — POST JSON is the same object the client sends inside api_payload when encrypted.
 package main

@@ -6,10 +6,15 @@ import (
 	"bytes"
 	"encoding/base64"
 	"encoding/json"
+	"flag"
+	"fmt"
 	"io"
 	"log"
 	"net"
 	"net/http"
+	"os"
+	"sort"
+	"strings"
 	"sync"
 	"time"

@@ -23,19 +28,17 @@ func shortID(id string) string {
 	return id[:10] + "…"
 }

-// Set to 5 to mimic "more than 5 requests per 24h". Set to 0 so the first amnezia-free request returns CAPTCHA (faster UI test).
-const rateLimitExcessAfter = 0
-
 var (
 	mu       sync.Mutex
 	requests = map[string][]time.Time{} // installation_uuid -> timestamps (sliding window simplified: count in session)
 	sessions = map[string]*pairingSession{}
-)

-// Local dev only: gateway team agreed 120s for mock vs 30s production (task_1 docs).
-const (
-	pairingTTL        = 120 * time.Second
-	longPollWaitLimit = 120 * time.Second
+	// Configured from flags / env in main().
+	pairingSessionTTL    = 120 * time.Second
+	longPollWaitLimit    = 120 * time.Second
+	rateLimitExcessAfter = 0 // Set to 5 to mimic "more than 5 requests per 24h". 0 = first amnezia-free request may return CAPTCHA.
+	// No trailing slash; used by POST /v1/updater_endpoint so remote clients (e.g. iOS) poll the Mac, not 127.0.0.1 on-device.
+	publicUpdaterBaseURL string
 )

 type generateQRRequest struct {
@@ -85,11 +88,40 @@ func drainBody(r *http.Request) {
 	_ = r.Body.Close()
 }

-// logReq logs every request (step 5 in docs/local-gateway-mock.md).
+// statusResponseWriter captures HTTP status for access-style logging.
+type statusResponseWriter struct {
+	http.ResponseWriter
+	status  int
+	written bool
+}
+
+func (w *statusResponseWriter) WriteHeader(code int) {
+	if !w.written {
+		w.status = code
+		w.written = true
+	}
+	w.ResponseWriter.WriteHeader(code)
+}
+
+func (w *statusResponseWriter) Write(b []byte) (int, error) {
+	if !w.written {
+		w.status = http.StatusOK
+		w.written = true
+	}
+	return w.ResponseWriter.Write(b)
+}
+
+// logReq logs every request with remote addr, UA, and final status (docs/local-gateway-mock.md).
 func logReq(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		log.Printf("REQ %s %s", r.Method, r.URL.Path)
-		next(w, r)
+		srw := &statusResponseWriter{ResponseWriter: w, status: http.StatusOK}
+		start := time.Now()
+		log.Printf("REQ start remote=%s method=%s path=%s query=%s ua=%q x_client_request_id=%q content_type=%q content_length=%d",
+			r.RemoteAddr, r.Method, r.URL.Path, r.URL.RawQuery, r.Header.Get("User-Agent"), r.Header.Get("X-Client-Request-ID"),
+			r.Header.Get("Content-Type"), r.ContentLength)
+		next(srw, r)
+		log.Printf("REQ end remote=%s method=%s path=%s status=%d dur=%s",
+			r.RemoteAddr, r.Method, r.URL.Path, srw.status, time.Since(start).Round(time.Millisecond))
 	}
 }

@@ -153,7 +185,7 @@ func handleGenerateQR(w http.ResponseWriter, r *http.Request) {

 	session := &pairingSession{
 		QRUUID:    req.QRUUID,
-		ExpiresAt: time.Now().Add(pairingTTL),
+		ExpiresAt: time.Now().Add(pairingSessionTTL),
 		Done:      make(chan struct{}),
 	}

@@ -162,7 +194,8 @@ func handleGenerateQR(w http.ResponseWriter, r *http.Request) {
 	sessions[req.QRUUID] = session
 	mu.Unlock()

-	log.Printf("pairing REGISTERED uuid=%s ttl=%s", shortID(req.QRUUID), pairingTTL)
+	log.Printf("pairing REGISTERED uuid=%s install=%s ttl=%s app=%s os=%s",
+		shortID(req.QRUUID), shortID(req.InstallationUUID), pairingSessionTTL, req.AppVersion, req.OSVersion)

 	timer := time.NewTimer(longPollWaitLimit)
 	defer timer.Stop()
@@ -247,7 +280,8 @@ func handleScanQR(w http.ResponseWriter, r *http.Request) {
 	close(session.Done)
 	mu.Unlock()

-	log.Printf("pairing COMPLETED uuid=%s config_len=%d", shortID(req.QRUUID), len(req.Config))
+	log.Printf("pairing COMPLETED uuid=%s phone_install=%s config_len=%d proto_count=%d",
+		shortID(req.QRUUID), shortID(req.InstallationUUID), len(req.Config), len(req.SupportedProto))
 	writeJSON(w, http.StatusOK, map[string]string{"message": "OK"})
 }

@@ -457,7 +491,8 @@ func handleUpdaterEndpoint(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	drainBody(r)
-	writeJSON(w, http.StatusOK, map[string]string{"url": "http://127.0.0.1:8080"})
+	log.Printf("updater_endpoint response url=%q", publicUpdaterBaseURL)
+	writeJSON(w, http.StatusOK, map[string]string{"url": publicUpdaterBaseURL})
 }

 // POST /v1/revoke_config, /v1/revoke_native_config — success body ignored if error is NoError.
@@ -498,7 +533,148 @@ func handleGetReleaseDate(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 }

+func envOrDefault(key, def string) string {
+	if v := strings.TrimSpace(os.Getenv(key)); v != "" {
+		return v
+	}
+	return def
+}
+
+func cloneIPv4(ip net.IP) net.IP {
+	x := make(net.IP, 4)
+	copy(x, ip.To4())
+	return x
+}
+
+// pickLANIPv4 returns a stable choice of non-loopback IPv4 for updater_endpoint / banners (prefers private ULA space).
+func pickLANIPv4() net.IP {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		log.Printf("net.Interfaces: %v", err)
+		return nil
+	}
+	type cand struct {
+		ip      net.IP
+		private bool
+		name    string
+	}
+	var cands []cand
+	for _, iface := range ifaces {
+		if iface.Flags&net.FlagUp == 0 {
+			continue
+		}
+		if iface.Flags&net.FlagLoopback != 0 {
+			continue
+		}
+		addrs, err := iface.Addrs()
+		if err != nil {
+			continue
+		}
+		for _, a := range addrs {
+			ipNet, ok := a.(*net.IPNet)
+			if !ok {
+				continue
+			}
+			ip4 := ipNet.IP.To4()
+			if ip4 == nil || ip4.IsLoopback() {
+				continue
+			}
+			priv := ip4.IsPrivate() || ip4.IsLinkLocalUnicast()
+			cands = append(cands, cand{ip: cloneIPv4(ip4), private: priv, name: iface.Name})
+			log.Printf("iface candidate name=%s ip=%s private_or_linklocal=%v", iface.Name, ip4, priv)
+		}
+	}
+	if len(cands) == 0 {
+		return nil
+	}
+	sort.SliceStable(cands, func(i, j int) bool {
+		if cands[i].private != cands[j].private {
+			return cands[i].private
+		}
+		if cands[i].name != cands[j].name {
+			return cands[i].name < cands[j].name
+		}
+		return bytes.Compare(cands[i].ip, cands[j].ip) < 0
+	})
+	chosen := cands[0].ip
+	log.Printf("pickLANIPv4: using %s (iface_hint=%s)", chosen, cands[0].name)
+	return chosen
+}
+
+func normalizePublicBase(s string) string {
+	s = strings.TrimSpace(s)
+	s = strings.TrimSuffix(s, "/")
+	return s
+}
+
+func logStartupURLs(listenAddr, portStr string) {
+	log.Printf("=== local_gateway (plaintext mock) ===")
+	log.Printf("listen tcp4: %s", listenAddr)
+	log.Printf("POST /v1/updater_endpoint will return: {\"url\": %q}", publicUpdaterBaseURL)
+	log.Printf("Point AmneziaVPN gateway setting to: %s/", publicUpdaterBaseURL)
+	log.Printf("Try from phone browser: %s/", publicUpdaterBaseURL)
+	log.Printf("Non-loopback IPv4 URLs (same listen port %s):", portStr)
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		log.Printf("  (could not enumerate interfaces: %v)", err)
+	} else {
+		for _, iface := range ifaces {
+			if iface.Flags&net.FlagUp == 0 || iface.Flags&net.FlagLoopback != 0 {
+				continue
+			}
+			addrs, _ := iface.Addrs()
+			for _, a := range addrs {
+				ipNet, ok := a.(*net.IPNet)
+				if !ok {
+					continue
+				}
+				if ip4 := ipNet.IP.To4(); ip4 != nil && !ip4.IsLoopback() {
+					log.Printf("  http://%s:%s/  (iface %s)", ip4, portStr, iface.Name)
+				}
+			}
+		}
+	}
+	log.Printf("docs: tools/local_gateway/README.md tools/local_gateway/LAN_GATEWAY.md")
+	log.Printf("========================================")
+}
+
 func main() {
+	listenFlag := flag.String("listen", envOrDefault("LOCAL_GATEWAY_LISTEN", "0.0.0.0:8080"),
+		"TCP listen address (tcp4). Env: LOCAL_GATEWAY_LISTEN")
+	publicFlag := flag.String("public-base", strings.TrimSpace(os.Getenv("LOCAL_GATEWAY_PUBLIC_BASE")),
+		"Base URL without trailing slash for /v1/updater_endpoint (required for iOS-on-LAN). Env: LOCAL_GATEWAY_PUBLIC_BASE")
+	autoPublic := flag.Bool("auto-public", true, "If public-base empty, derive http://<first-lan-ipv4>:port")
+	pairTTL := flag.Duration("pairing-ttl", 120*time.Second, "QR pairing session TTL")
+	longPoll := flag.Duration("long-poll", 120*time.Second, "Long-poll max wait for POST /api/v1/generate_qr")
+	rateN := flag.Int("rate-limit-excess-after", 0, "Amnezia Free: allow N requests per 24h window before rate-limit/CAPTCHA (0=tight)")
+	flag.Parse()
+
+	listenAddr := strings.TrimSpace(*listenFlag)
+	if _, _, err := net.SplitHostPort(listenAddr); err != nil {
+		listenAddr = net.JoinHostPort(listenAddr, "8080")
+	}
+	_, portStr, err := net.SplitHostPort(listenAddr)
+	if err != nil {
+		log.Fatalf("listen address: %v", err)
+	}
+
+	pairingSessionTTL = *pairTTL
+	longPollWaitLimit = *longPoll
+	rateLimitExcessAfter = *rateN
+
+	pub := normalizePublicBase(*publicFlag)
+	if pub == "" && *autoPublic {
+		if ip := pickLANIPv4(); ip != nil {
+			pub = fmt.Sprintf("http://%s:%s", ip.String(), portStr)
+			log.Printf("auto-public: updater + docs base -> %s (override with -public-base or LOCAL_GATEWAY_PUBLIC_BASE)", pub)
+		}
+	}
+	if pub == "" {
+		pub = fmt.Sprintf("http://127.0.0.1:%s", portStr)
+		log.Printf("WARN: public-base not set and auto-public found no LAN IPv4; using %s (broken for remote phones). Set -public-base or LOCAL_GATEWAY_PUBLIC_BASE.", pub)
+	}
+	publicUpdaterBaseURL = pub
+
 	http.HandleFunc("/", logReq(handleRoot))
 	http.HandleFunc("/VERSION", logReq(handleGetVersion))
 	http.HandleFunc("/CHANGELOG", logReq(handleGetChangelog))
@@ -513,11 +689,13 @@ func main() {
 	http.HandleFunc("/v1/revoke_native_config", logReq(handleRevokeNoop))
 	http.HandleFunc("/api/v1/generate_qr", logReq(handleGenerateQR))
 	http.HandleFunc("/api/v1/scan_qr", logReq(handleScanQR))
-	const addr = "0.0.0.0:8080"
-	log.Printf("plaintext mock on tcp4 %s — see tools/local_gateway/README.md for paths\n", addr)
-	ln, err := net.Listen("tcp4", addr)
+
+	logStartupURLs(listenAddr, portStr)
+
+	ln, err := net.Listen("tcp4", listenAddr)
 	if err != nil {
 		log.Fatal(err)
 	}
+	log.Printf("listening tcp4 %s (actual %v)", listenAddr, ln.Addr())
 	log.Fatal(http.Serve(ln, nil))
 }
--- a/tools/local_gateway/verify.sh
+++ b/tools/local_gateway/verify.sh
@@ -5,6 +5,8 @@
 set -euo pipefail
 BASE="${1:-http://127.0.0.1:8080}"

+echo "== local_gateway verify base: ${BASE} =="
+
 echo "== GET / =="
 curl -sfS "$BASE/" | head -n 2