fix potential race in socket closure

src/AsyncHTTPServer.cc

@@ -335,7 +335,7 @@ asio::awaitable<WebSocketMessage> HTTPClient::recv_websocket_message(size_t max_
       } else if (opcode == 0x08) {
         // Close message
         co_await this->send_websocket_message(msg.data, msg.opcode);
-        this->r.get_socket().close();
+        this->r.close();
 
       } else if (opcode == 0x09) {
         // Ping message
@@ -343,7 +343,7 @@ asio::awaitable<WebSocketMessage> HTTPClient::recv_websocket_message(size_t max_
 
       } else {
         // Unknown control message type
-        this->r.get_socket().close();
+        this->r.close();
       }
       continue;
     }
@@ -351,7 +351,7 @@ asio::awaitable<WebSocketMessage> HTTPClient::recv_websocket_message(size_t max_
     // If there's an existing fragment, the current message's opcode should be
     // zero; if there's no pending message, it must not be zero
     if (prev_msg_present == (opcode != 0)) {
-      this->r.get_socket().close();
+      this->r.close();
       continue;
     }
 

src/AsyncUtils.hh

@@ -189,8 +189,14 @@ public:
     return this->sock;
   }
 
+  inline bool is_open() const {
+    return this->sock.is_open();
+  }
+
   inline void close() {
-    this->sock.close();
+    if (this->sock.is_open()) {
+      this->sock.close();
+    }
   }
 
 private:

src/GameServer.cc

@@ -118,7 +118,9 @@ vector<shared_ptr<Client>> GameServer::get_clients_by_identifier(const string& i
 shared_ptr<Client> GameServer::create_client(shared_ptr<GameServerSocket> listen_sock, asio::ip::tcp::socket&& client_sock) {
   uint32_t addr = ipv4_addr_for_asio_addr(client_sock.remote_endpoint().address());
   if (this->state->banned_ipv4_ranges->check(addr)) {
-    client_sock.close();
+    if (client_sock.is_open()) {
+      client_sock.close();
+    }
     return nullptr;
   }
 

src/IPStackSimulator.cc

@@ -154,7 +154,9 @@ void IPSSClient::reschedule_idle_timeout() {
   this->idle_timeout_timer.async_wait([this, sim](std::error_code ec) {
     if (!ec) {
       sim->log.info_f("Idle timeout expired on N-{:X}", this->network_id);
-      this->sock.close();
+      if (this->sock.is_open()) {
+        this->sock.close();
+      }
     }
   });
 }
@@ -1233,11 +1235,9 @@ asio::awaitable<void> IPStackSimulator::on_client_tcp_frame(shared_ptr<IPSSClien
 
         // Send the new data to the server
         if (!conn->server_channel) {
-          this->log.warning_f("Client sent data on TCP connection {}, but server channel is missing",
-              conn_str);
+          this->log.warning_f("Client sent data on TCP connection {}, but server channel is missing", conn_str);
         } else if (!conn->server_channel->connected()) {
-          this->log.warning_f("Client sent data on TCP connection {}, but server channel is disconnected",
-              conn_str);
+          this->log.warning_f("Client sent data on TCP connection {}, but server channel is disconnected", conn_str);
         } else {
           conn->server_channel->add_inbound_data(payload, payload_size);
         }
@@ -1425,7 +1425,9 @@ std::shared_ptr<IPSSClient> IPStackSimulator::create_client(
     std::shared_ptr<IPSSSocket> listen_sock, asio::ip::tcp::socket&& client_sock) {
   uint32_t addr = ipv4_addr_for_asio_addr(client_sock.remote_endpoint().address());
   if (this->state->banned_ipv4_ranges->check(addr)) {
-    client_sock.close();
+    if (client_sock.is_open()) {
+      client_sock.close();
+    }
     return nullptr;
   }