refactor(gateway): move request client ip resolution to net

src/gateway/auth.ts

@@ -16,6 +16,7 @@ import { resolveGatewayCredentialsFromValues } from "./credentials.js";
 import {
   isLocalishHost,
   isLoopbackAddress,
+  resolveRequestClientIp,
   isTrustedProxyAddress,
   resolveClientIp,
 } from "./net.js";
@@ -105,23 +106,6 @@ function resolveTailscaleClientIp(req?: IncomingMessage): string | undefined {
   });
 }
 
-export function resolveRequestClientIp(
-  req?: IncomingMessage,
-  trustedProxies?: string[],
-  allowRealIpFallback = false,
-): string | undefined {
-  if (!req) {
-    return undefined;
-  }
-  return resolveClientIp({
-    remoteAddr: req.socket?.remoteAddress ?? "",
-    forwardedFor: headerValue(req.headers?.["x-forwarded-for"]),
-    realIp: headerValue(req.headers?.["x-real-ip"]),
-    trustedProxies,
-    allowRealIpFallback,
-  });
-}
-
 export function isLocalDirectRequest(
   req?: IncomingMessage,
   trustedProxies?: string[],

src/gateway/net.ts

@@ -1,3 +1,4 @@
+import type { IncomingMessage } from "node:http";
 import net from "node:net";
 import os from "node:os";
 import { pickPrimaryTailnetIPv4, pickPrimaryTailnetIPv6 } from "../infra/tailnet.js";
@@ -184,6 +185,27 @@ export function resolveClientIp(params: {
   return undefined;
 }
 
+function headerValue(value: string | string[] | undefined): string | undefined {
+  return Array.isArray(value) ? value[0] : value;
+}
+
+export function resolveRequestClientIp(
+  req?: IncomingMessage,
+  trustedProxies?: string[],
+  allowRealIpFallback = false,
+): string | undefined {
+  if (!req) {
+    return undefined;
+  }
+  return resolveClientIp({
+    remoteAddr: req.socket?.remoteAddress ?? "",
+    forwardedFor: headerValue(req.headers?.["x-forwarded-for"]),
+    realIp: headerValue(req.headers?.["x-real-ip"]),
+    trustedProxies,
+    allowRealIpFallback,
+  });
+}
+
 export function isLocalGatewayAddress(ip: string | undefined): boolean {
   if (isLoopbackAddress(ip)) {
     return true;

src/gateway/server-http.ts

@@ -23,7 +23,6 @@ import {
 import {
   authorizeHttpGatewayConnect,
   isLocalDirectRequest,
-  resolveRequestClientIp,
   type GatewayAuthResult,
   type ResolvedGatewayAuth,
 } from "./auth.js";
@@ -53,6 +52,7 @@ import {
 } from "./hooks.js";
 import { sendGatewayAuthFailure, setDefaultSecurityHeaders } from "./http-common.js";
 import { getBearerToken } from "./http-utils.js";
+import { resolveRequestClientIp } from "./net.js";
 import { handleOpenAiHttpRequest } from "./openai-http.js";
 import { handleOpenResponsesHttpRequest } from "./openresponses-http.js";
 import {