diff --git a/esphome/components/web_server_idf/web_server_idf.cpp b/esphome/components/web_server_idf/web_server_idf.cpp index f5a66f6bd9..c910ed06c5 100644 --- a/esphome/components/web_server_idf/web_server_idf.cpp +++ b/esphome/components/web_server_idf/web_server_idf.cpp @@ -87,6 +87,29 @@ int nonblocking_send(httpd_handle_t hd, int sockfd, const char *buf, size_t buf_ } } // namespace +void AsyncWebServer::safe_close_with_shutdown(httpd_handle_t hd, int sockfd) { + // CRITICAL: Shut down receive BEFORE closing to prevent lwIP race conditions + // + // The race condition occurs because close() initiates lwIP teardown while + // the TCP/IP thread can still receive packets, causing assertions when + // recv_tcp() sees partially-torn-down state. + // + // By shutting down receive first, we tell lwIP to stop accepting new data BEFORE + // the teardown begins, eliminating the race window. We only shutdown RD (not RDWR) + // to allow the FIN packet to be sent cleanly during close(). + // + // Note: This function may be called with an already-closed socket if the network + // stack closed it. In that case, shutdown() will fail but close() is safe to call. + // + // See: https://github.com/esphome/esphome-webserver/issues/163 + + // Attempt shutdown - ignore errors as socket may already be closed + shutdown(sockfd, SHUT_RD); + + // Always close - safe even if socket is already closed by network stack + close(sockfd); +} + void AsyncWebServer::end() { if (this->server_) { httpd_stop(this->server_); @@ -115,6 +138,8 @@ void AsyncWebServer::begin() { config.uri_match_fn = [](const char * /*unused*/, const char * /*unused*/, size_t /*unused*/) { return true; }; // Enable LRU purging if requested (e.g., by captive portal to handle probe bursts) config.lru_purge_enable = this->lru_purge_enable_; + // Use custom close function that shuts down before closing to prevent lwIP race conditions + config.close_fn = AsyncWebServer::safe_close_with_shutdown; if (httpd_start(&this->server_, &config) == ESP_OK) { const httpd_uri_t handler_get = { .uri = "", @@ -505,17 +530,11 @@ AsyncEventSourceResponse::AsyncEventSourceResponse(const AsyncWebServerRequest * void AsyncEventSourceResponse::destroy(void *ptr) { auto *rsp = static_cast(ptr); int fd = rsp->fd_.exchange(0); // Atomically get and clear fd - - if (fd > 0) { - ESP_LOGD(TAG, "Event source connection closed (fd: %d)", fd); - // Immediately shut down the socket to prevent lwIP from delivering more data - // This prevents "recv_tcp: recv for wrong pcb!" assertions when the TCP stack - // tries to deliver queued data after the session is marked as dead - // See: https://github.com/esphome/esphome/issues/11936 - shutdown(fd, SHUT_RDWR); - // Note: We don't close() the socket - httpd owns it and will close it - } - // Session will be cleaned up in the main loop to avoid race conditions + ESP_LOGD(TAG, "Event source connection closed (fd: %d)", fd); + // Mark as dead - will be cleaned up in the main loop + // Note: We don't delete or remove from set here to avoid race conditions + // httpd will call our custom close_fn (safe_close_with_shutdown) which handles + // shutdown() before close() to prevent lwIP race conditions } // helper for allowing only unique entries in the queue diff --git a/esphome/components/web_server_idf/web_server_idf.h b/esphome/components/web_server_idf/web_server_idf.h index b9f690b462..a139e9e4df 100644 --- a/esphome/components/web_server_idf/web_server_idf.h +++ b/esphome/components/web_server_idf/web_server_idf.h @@ -209,6 +209,7 @@ class AsyncWebServer { static esp_err_t request_handler(httpd_req_t *r); static esp_err_t request_post_handler(httpd_req_t *r); esp_err_t request_handler_(AsyncWebServerRequest *request) const; + static void safe_close_with_shutdown(httpd_handle_t hd, int sockfd); #ifdef USE_WEBSERVER_OTA esp_err_t handle_multipart_upload_(httpd_req_t *r, const char *content_type); #endif