Add UWS_REMOTE_ADDRESS_USERSPACE macro for userspace remote address caching (#1917)

* Initial plan

* Add UWS_REMOTE_ADDRESS_USERSPACE macro for caching remote address in per-socket data

Co-authored-by: uNetworkingAB <110806833+uNetworkingAB@users.noreply.github.com>

* Remove test binaries and add .gitignore

Co-authored-by: uNetworkingAB <110806833+uNetworkingAB@users.noreply.github.com>

* Delete .gitignore

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: uNetworkingAB <110806833+uNetworkingAB@users.noreply.github.com>

Author: Copilot

src/AsyncSocket.h

@@ -219,10 +219,15 @@ struct AsyncSocket {
 
     /* Returns the remote IP address or empty string on failure */
     std::string_view getRemoteAddress() {
+#ifdef UWS_REMOTE_ADDRESS_USERSPACE
+        AsyncSocketData<SSL> *data = getAsyncSocketData();
+        return std::string_view(data->remoteAddress, (unsigned int) data->remoteAddressLength);
+#else
         static thread_local char buf[16];
         int ipLength = 16;
         us_socket_remote_address(SSL, (us_socket_t *) this, buf, &ipLength);
         return std::string_view(buf, (unsigned int) ipLength);
+#endif
     }
 
     /* Returns the text representation of IP */

src/AsyncSocketData.h

@@ -74,6 +74,12 @@ struct AsyncSocketData {
     /* This will do for now */
     BackPressure buffer;
 
+#ifdef UWS_REMOTE_ADDRESS_USERSPACE
+    /* Cache for remote address, populated on socket open */
+    char remoteAddress[16];
+    int remoteAddressLength = 0;
+#endif
+
     /* Allow move constructing us */
     AsyncSocketData(BackPressure &&backpressure) : buffer(std::move(backpressure)) {
 

src/HttpContext.h

@@ -69,13 +69,27 @@ struct HttpContext {
     /* Init the HttpContext by registering libusockets event handlers */
     HttpContext<SSL> *init() {
         /* Handle socket connections */
-        us_socket_context_on_open(SSL, getSocketContext(), [](us_socket_t *s, int /*is_client*/, char */*ip*/, int /*ip_length*/) {
+        us_socket_context_on_open(SSL, getSocketContext(), [](us_socket_t *s, int /*is_client*/, char *ip, int ip_length) {
             /* Any connected socket should timeout until it has a request */
             us_socket_timeout(SSL, s, HTTP_IDLE_TIMEOUT_S);
 
             /* Init socket ext */
             new (us_socket_ext(SSL, s)) HttpResponseData<SSL>;
 
+#ifdef UWS_REMOTE_ADDRESS_USERSPACE
+            /* Copy remote address into per-socket cache for later retrieval */
+            AsyncSocketData<SSL> *asyncSocketData = (AsyncSocketData<SSL> *) us_socket_ext(SSL, s);
+            if (ip_length > 0 && ip_length <= 16) {
+                memcpy(asyncSocketData->remoteAddress, ip, (size_t) ip_length);
+                asyncSocketData->remoteAddressLength = ip_length;
+            } else {
+                asyncSocketData->remoteAddressLength = 0;
+            }
+#else
+            (void) ip;
+            (void) ip_length;
+#endif
+
             /* Call filter */
             HttpContextData<SSL> *httpContextData = getSocketContextDataS(s);
             for (auto &f : httpContextData->filterHandlers) {