windows: SO_EXCLUSIVEADDRUSE

https://github.com/warmcat/libwebsockets/issues/942

diff --git a/lib/libwebsockets.h b/lib/libwebsockets.h
index ad754b0..2214b01 100644 (file)
--- a/lib/libwebsockets.h
+++ b/lib/libwebsockets.h
@@ -1800,6 +1800,12 @@ enum lws_context_options {
        /**< (VH) All connections to this vhost / port are RAW as soon as
         * the connection is accepted, no HTTP is going to be coming.
         */
+       LWS_SERVER_OPTION_ALLOW_LISTEN_SHARE                    = (1 << 23),
+       /**< (VH) Set to allow multiple listen sockets on one interface +
+        * address + port.  The default is to strictly allow only one
+        * listen socket at a time.  This is automatically selected if you
+        * have multiple service threads.
+        */
 
        /****** add new things just above ---^ ******/
 };

diff --git a/lib/server.c b/lib/server.c
index 2693cc0..159c140 100644 (file)
--- a/lib/server.c
+++ b/lib/server.c
@@ -65,6 +65,7 @@ lws_context_init_server(struct lws_context_creation_info *info,
        }
 
 #if LWS_POSIX
+       (void)n;
 #if defined(__linux__)
        limit = vhost->context->count_threads;
 #endif
@@ -93,6 +94,24 @@ lws_context_init_server(struct lws_context_creation_info *info,
                return 1;
        }
 #if LWS_POSIX && !defined(LWS_WITH_ESP32)
+
+#if (defined(WIN32) || defined(_WIN32)) && defined(SO_EXCLUSIVEADDRUSE)
+       /*
+        * only accept that we are the only listener on the port
+        * https://msdn.microsoft.com/zh-tw/library/windows/desktop/ms740621(v=vs.85).aspx
+        *
+        * for lws, to match Linux, we default to exclusive listen
+        */
+       if (!lws_check_opt(vhost->options, LWS_SERVER_OPTION_ALLOW_LISTEN_SHARE)) {
+               if (setsockopt(sockfd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE,
+                              (const void *)&opt, sizeof(opt)) < 0) {
+                       lwsl_err("reuseaddr failed\n");
+                       compatible_close(sockfd);
+                       return 1;
+               }
+       } else
+#endif
+
        /*
         * allow us to restart even if old sockets in TIME_WAIT
         */
@@ -116,13 +135,19 @@ lws_context_init_server(struct lws_context_creation_info *info,
        }
 #endif
 
-#if defined(__linux__) && defined(SO_REUSEPORT) && LWS_MAX_SMP > 1
-       if (vhost->context->count_threads > 1)
-               if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEPORT,
-                               (const void *)&opt, sizeof(opt)) < 0) {
-                       compatible_close(sockfd);
-                       return 1;
-               }
+#if defined(__linux__) && defined(SO_REUSEPORT)
+       n = lws_check_opt(vhost->options, LWS_SERVER_OPTION_ALLOW_LISTEN_SHARE);
+#if LWS_MAX_SMP > 1
+       n = 1;
+#endif
+
+       if (n)
+               if (vhost->context->count_threads > 1)
+                       if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEPORT,
+                                       (const void *)&opt, sizeof(opt)) < 0) {
+                               compatible_close(sockfd);
+                               return 1;
+                       }
 #endif
 #endif
        lws_plat_set_socket_options(vhost, sockfd);