#include #include #include #include #include #include "esp_log.h" #include "esp_transport.h" #include "esp_transport_tcp.h" #include "esp_transport_ws.h" #include "esp_transport_utils.h" #include "esp_transport_internal.h" #include "errno.h" #include "esp_tls_crypto.h" static const char *TAG = "TRANSPORT_WS"; #define WS_BUFFER_SIZE CONFIG_WS_BUFFER_SIZE #define WS_FIN 0x80 #define WS_OPCODE_CONT 0x00 #define WS_OPCODE_TEXT 0x01 #define WS_OPCODE_BINARY 0x02 #define WS_OPCODE_CLOSE 0x08 #define WS_OPCODE_PING 0x09 #define WS_OPCODE_PONG 0x0a #define WS_OPCODE_CONTROL_FRAME 0x08 // Second byte #define WS_MASK 0x80 #define WS_SIZE16 126 #define WS_SIZE64 127 #define MAX_WEBSOCKET_HEADER_SIZE 16 #define WS_RESPONSE_OK 101 #define WS_TRANSPORT_MAX_CONTROL_FRAME_BUFFER_LEN 125 typedef struct { uint8_t opcode; char mask_key[4]; /*!< Mask key for this payload */ int payload_len; /*!< Total length of the payload */ int bytes_remaining; /*!< Bytes left to read of the payload */ bool header_received; /*!< Flag to indicate that a new message header was received */ } ws_transport_frame_state_t; typedef struct { char *path; char *buffer; char *sub_protocol; char *user_agent; char *headers; bool propagate_control_frames; ws_transport_frame_state_t frame_state; esp_transport_handle_t parent; } transport_ws_t; /** * @brief Handles control frames * * This API is used internally to handle control frames at the transport layer. * The API could be possibly promoted to a public API if needed by some clients * * @param t Websocket transport handle * @param buffer Buffer with the actual payload of the control packet to be processed * @param len Length of the buffer (typically the same as the payload buffer) * @param timeout_ms The timeout milliseconds * @param client_closed To indicate that the connection has been closed by the client * (to prevent echoing the CLOSE packet if true, as this is the actual echo from the server) * * @return * 0 - no activity, or successfully responded to PING * -1 - Failure: Error on read or the actual payload longer then buffer * 1 - Close handshake success * 2 - Got PONG message */ static int esp_transport_ws_handle_control_frames(esp_transport_handle_t t, char *buffer, int len, int timeout_ms, bool client_closed); static inline uint8_t ws_get_bin_opcode(ws_transport_opcodes_t opcode) { return (uint8_t)opcode; } static esp_transport_handle_t ws_get_payload_transport_handle(esp_transport_handle_t t) { transport_ws_t *ws = esp_transport_get_context_data(t); /* Reading parts of a frame directly will disrupt the WS internal frame state, reset bytes_remaining to prepare for reading a new frame */ ws->frame_state.bytes_remaining = 0; return ws->parent; } static char *trimwhitespace(const char *str) { char *end; // Trim leading space while (isspace((unsigned char)*str)) str++; if (*str == 0) { return (char *)str; } // Trim trailing space end = (char *)(str + strlen(str) - 1); while (end > str && isspace((unsigned char)*end)) end--; // Write new null terminator *(end + 1) = 0; return (char *)str; } static char *get_http_header(const char *buffer, const char *key) { char *found = strcasestr(buffer, key); if (found) { found += strlen(key); char *found_end = strstr(found, "\r\n"); if (found_end) { found_end[0] = 0;//terminal string return trimwhitespace(found); } } return NULL; } static int ws_connect(esp_transport_handle_t t, const char *host, int port, int timeout_ms) { transport_ws_t *ws = esp_transport_get_context_data(t); if (esp_transport_connect(ws->parent, host, port, timeout_ms) < 0) { ESP_LOGE(TAG, "Error connecting to host %s:%d", host, port); return -1; } unsigned char random_key[16]; getrandom(random_key, sizeof(random_key), 0); // Size of base64 coded string is equal '((input_size * 4) / 3) + (input_size / 96) + 6' including Z-term unsigned char client_key[28] = {0}; const char *user_agent_ptr = (ws->user_agent)?(ws->user_agent):"ESP32 Websocket Client"; size_t outlen = 0; esp_crypto_base64_encode(client_key, sizeof(client_key), &outlen, random_key, sizeof(random_key)); int len = snprintf(ws->buffer, WS_BUFFER_SIZE, "GET %s HTTP/1.1\r\n" "Connection: Upgrade\r\n" "Host: %s:%d\r\n" "User-Agent: %s\r\n" "Upgrade: websocket\r\n" "Sec-WebSocket-Version: 13\r\n" "Sec-WebSocket-Key: %s\r\n", ws->path, host, port, user_agent_ptr, client_key); if (len <= 0 || len >= WS_BUFFER_SIZE) { ESP_LOGE(TAG, "Error in request generation, desired request len: %d, buffer size: %d", len, WS_BUFFER_SIZE); return -1; } if (ws->sub_protocol) { ESP_LOGD(TAG, "sub_protocol: %s", ws->sub_protocol); int r = snprintf(ws->buffer + len, WS_BUFFER_SIZE - len, "Sec-WebSocket-Protocol: %s\r\n", ws->sub_protocol); len += r; if (r <= 0 || len >= WS_BUFFER_SIZE) { ESP_LOGE(TAG, "Error in request generation" "(snprintf of subprotocol returned %d, desired request len: %d, buffer size: %d", r, len, WS_BUFFER_SIZE); return -1; } } if (ws->headers) { ESP_LOGD(TAG, "headers: %s", ws->headers); int r = snprintf(ws->buffer + len, WS_BUFFER_SIZE - len, "%s", ws->headers); len += r; if (r <= 0 || len >= WS_BUFFER_SIZE) { ESP_LOGE(TAG, "Error in request generation" "(strncpy of headers returned %d, desired request len: %d, buffer size: %d", r, len, WS_BUFFER_SIZE); return -1; } } int r = snprintf(ws->buffer + len, WS_BUFFER_SIZE - len, "\r\n"); len += r; if (r <= 0 || len >= WS_BUFFER_SIZE) { ESP_LOGE(TAG, "Error in request generation" "(snprintf of header terminal returned %d, desired request len: %d, buffer size: %d", r, len, WS_BUFFER_SIZE); return -1; } ESP_LOGD(TAG, "Write upgrade request\r\n%s", ws->buffer); if (esp_transport_write(ws->parent, ws->buffer, len, timeout_ms) <= 0) { ESP_LOGE(TAG, "Error write Upgrade header %s", ws->buffer); return -1; } int header_len = 0; do { if ((len = esp_transport_read(ws->parent, ws->buffer + header_len, WS_BUFFER_SIZE - header_len, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error read response for Upgrade header %s", ws->buffer); return -1; } header_len += len; ws->buffer[header_len] = '\0'; ESP_LOGD(TAG, "Read header chunk %d, current header size: %d", len, header_len); } while (NULL == strstr(ws->buffer, "\r\n\r\n") && header_len < WS_BUFFER_SIZE); char *server_key = get_http_header(ws->buffer, "Sec-WebSocket-Accept:"); if (server_key == NULL) { ESP_LOGE(TAG, "Sec-WebSocket-Accept not found"); return -1; } // See esp_crypto_sha1() arg size unsigned char expected_server_sha1[20]; // Size of base64 coded string see above unsigned char expected_server_key[33] = {0}; // If you are interested, see https://tools.ietf.org/html/rfc6455 const char expected_server_magic[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"; unsigned char expected_server_text[sizeof(client_key) + sizeof(expected_server_magic) + 1]; strcpy((char*)expected_server_text, (char*)client_key); strcat((char*)expected_server_text, expected_server_magic); size_t key_len = strlen((char*)expected_server_text); esp_crypto_sha1(expected_server_text, key_len, expected_server_sha1); esp_crypto_base64_encode(expected_server_key, sizeof(expected_server_key), &outlen, expected_server_sha1, sizeof(expected_server_sha1)); expected_server_key[ (outlen < sizeof(expected_server_key)) ? outlen : (sizeof(expected_server_key) - 1) ] = 0; ESP_LOGD(TAG, "server key=%s, send_key=%s, expected_server_key=%s", (char *)server_key, (char*)client_key, expected_server_key); if (strcmp((char*)expected_server_key, (char*)server_key) != 0) { ESP_LOGE(TAG, "Invalid websocket key"); return -1; } return 0; } static int _ws_write(esp_transport_handle_t t, int opcode, int mask_flag, const char *b, int len, int timeout_ms) { transport_ws_t *ws = esp_transport_get_context_data(t); char *buffer = (char *)b; char ws_header[MAX_WEBSOCKET_HEADER_SIZE]; char *mask; int header_len = 0, i; int poll_write; if ((poll_write = esp_transport_poll_write(ws->parent, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error transport_poll_write"); return poll_write; } ws_header[header_len++] = opcode; if (len <= 125) { ws_header[header_len++] = (uint8_t)(len | mask_flag); } else if (len < 65536) { ws_header[header_len++] = WS_SIZE16 | mask_flag; ws_header[header_len++] = (uint8_t)(len >> 8); ws_header[header_len++] = (uint8_t)(len & 0xFF); } else { ws_header[header_len++] = WS_SIZE64 | mask_flag; /* Support maximum 4 bytes length */ ws_header[header_len++] = 0; //(uint8_t)((len >> 56) & 0xFF); ws_header[header_len++] = 0; //(uint8_t)((len >> 48) & 0xFF); ws_header[header_len++] = 0; //(uint8_t)((len >> 40) & 0xFF); ws_header[header_len++] = 0; //(uint8_t)((len >> 32) & 0xFF); ws_header[header_len++] = (uint8_t)((len >> 24) & 0xFF); ws_header[header_len++] = (uint8_t)((len >> 16) & 0xFF); ws_header[header_len++] = (uint8_t)((len >> 8) & 0xFF); ws_header[header_len++] = (uint8_t)((len >> 0) & 0xFF); } if (mask_flag) { mask = &ws_header[header_len]; getrandom(ws_header + header_len, 4, 0); header_len += 4; for (i = 0; i < len; ++i) { buffer[i] = (buffer[i] ^ mask[i % 4]); } } if (esp_transport_write(ws->parent, ws_header, header_len, timeout_ms) != header_len) { ESP_LOGE(TAG, "Error write header"); return -1; } if (len == 0) { return 0; } int ret = esp_transport_write(ws->parent, buffer, len, timeout_ms); // in case of masked transport we have to revert back to the original data, as ws layer // does not create its own copy of data to be sent if (mask_flag) { mask = &ws_header[header_len-4]; for (i = 0; i < len; ++i) { buffer[i] = (buffer[i] ^ mask[i % 4]); } } return ret; } int esp_transport_ws_send_raw(esp_transport_handle_t t, ws_transport_opcodes_t opcode, const char *b, int len, int timeout_ms) { uint8_t op_code = ws_get_bin_opcode(opcode); if (t == NULL) { ESP_LOGE(TAG, "Transport must be a valid ws handle"); return ESP_ERR_INVALID_ARG; } ESP_LOGD(TAG, "Sending raw ws message with opcode %d", op_code); return _ws_write(t, op_code, WS_MASK, b, len, timeout_ms); } static int ws_write(esp_transport_handle_t t, const char *b, int len, int timeout_ms) { if (len == 0) { // Default transport write of zero length in ws layer sends out a ping message. // This behaviour could however be altered in IDF 5.0, since a separate API for sending // messages with user defined opcodes has been introduced. ESP_LOGD(TAG, "Write PING message"); return _ws_write(t, WS_OPCODE_PING | WS_FIN, WS_MASK, NULL, 0, timeout_ms); } return _ws_write(t, WS_OPCODE_BINARY | WS_FIN, WS_MASK, b, len, timeout_ms); } static int ws_read_payload(esp_transport_handle_t t, char *buffer, int len, int timeout_ms) { transport_ws_t *ws = esp_transport_get_context_data(t); int bytes_to_read; int rlen = 0; if (ws->frame_state.bytes_remaining > len) { ESP_LOGD(TAG, "Actual data to receive (%d) are longer than ws buffer (%d)", ws->frame_state.bytes_remaining, len); bytes_to_read = len; } else { bytes_to_read = ws->frame_state.bytes_remaining; } // Receive and process payload if (bytes_to_read != 0 && (rlen = esp_transport_read(ws->parent, buffer, bytes_to_read, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error read data"); return rlen; } ws->frame_state.bytes_remaining -= rlen; if (ws->frame_state.mask_key) { for (int i = 0; i < bytes_to_read; i++) { buffer[i] = (buffer[i] ^ ws->frame_state.mask_key[i % 4]); } } return rlen; } /* Read and parse the WS header, determine length of payload */ static int ws_read_header(esp_transport_handle_t t, char *buffer, int len, int timeout_ms) { transport_ws_t *ws = esp_transport_get_context_data(t); int payload_len; char ws_header[MAX_WEBSOCKET_HEADER_SIZE]; char *data_ptr = ws_header, mask; int rlen; int poll_read; ws->frame_state.header_received = false; if ((poll_read = esp_transport_poll_read(ws->parent, timeout_ms)) <= 0) { return poll_read; } // Receive and process header first (based on header size) int header = 2; int mask_len = 4; if ((rlen = esp_transport_read(ws->parent, data_ptr, header, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error read data"); return rlen; } ws->frame_state.header_received = true; ws->frame_state.opcode = (*data_ptr & 0x0F); data_ptr ++; mask = ((*data_ptr >> 7) & 0x01); payload_len = (*data_ptr & 0x7F); data_ptr++; ESP_LOGD(TAG, "Opcode: %d, mask: %d, len: %d\r\n", ws->frame_state.opcode, mask, payload_len); if (payload_len == 126) { // headerLen += 2; if ((rlen = esp_transport_read(ws->parent, data_ptr, header, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error read data"); return rlen; } payload_len = data_ptr[0] << 8 | data_ptr[1]; } else if (payload_len == 127) { // headerLen += 8; header = 8; if ((rlen = esp_transport_read(ws->parent, data_ptr, header, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error read data"); return rlen; } if (data_ptr[0] != 0 || data_ptr[1] != 0 || data_ptr[2] != 0 || data_ptr[3] != 0) { // really too big! payload_len = 0xFFFFFFFF; } else { payload_len = data_ptr[4] << 24 | data_ptr[5] << 16 | data_ptr[6] << 8 | data_ptr[7]; } } if (mask) { // Read and store mask if (payload_len != 0 && (rlen = esp_transport_read(ws->parent, buffer, mask_len, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error read data"); return rlen; } memcpy(ws->frame_state.mask_key, buffer, mask_len); } else { memset(ws->frame_state.mask_key, 0, mask_len); } ws->frame_state.payload_len = payload_len; ws->frame_state.bytes_remaining = payload_len; return payload_len; } static int ws_handle_control_frame_internal(esp_transport_handle_t t, int timeout_ms) { transport_ws_t *ws = esp_transport_get_context_data(t); char *control_frame_buffer = NULL; int control_frame_buffer_len = 0; int payload_len = ws->frame_state.payload_len; int ret = 0; // If no new header reception in progress, or not a control frame // just pass 0 -> no need to handle control frames if (ws->frame_state.header_received == false || !(ws->frame_state.opcode & WS_OPCODE_CONTROL_FRAME)) { return 0; } if (payload_len > WS_TRANSPORT_MAX_CONTROL_FRAME_BUFFER_LEN) { ESP_LOGE(TAG, "Not enough room for reading control frames (need=%d, max_allowed=%d)", ws->frame_state.payload_len, WS_TRANSPORT_MAX_CONTROL_FRAME_BUFFER_LEN); return -1; } // Now we can handle the control frame correctly (either zero payload, or a short one for which we allocate mem) control_frame_buffer_len = payload_len; if (control_frame_buffer_len > 0) { control_frame_buffer = malloc(control_frame_buffer_len); if (control_frame_buffer == NULL) { ESP_LOGE(TAG, "Cannot allocate buffer for control frames, need-%d", control_frame_buffer_len); return -1; } } else { control_frame_buffer_len = 0; } // read the payload of the control frame int actual_len = ws_read_payload(t, control_frame_buffer, control_frame_buffer_len, timeout_ms); if (actual_len != payload_len) { ESP_LOGE(TAG, "Control frame (opcode=%d) payload read failed (payload_len=%d, read_len=%d)", ws->frame_state.opcode, payload_len, actual_len); ret = -1; goto free_payload_buffer; } ret = esp_transport_ws_handle_control_frames(t, control_frame_buffer, control_frame_buffer_len, timeout_ms, false); free_payload_buffer: free(control_frame_buffer); return ret > 0 ? 0 : ret; // We don't propagate control frames, pass 0 to upper layers } static int ws_read(esp_transport_handle_t t, char *buffer, int len, int timeout_ms) { int rlen = 0; transport_ws_t *ws = esp_transport_get_context_data(t); // If message exceeds buffer len then subsequent reads will skip reading header and read whatever is left of the payload if (ws->frame_state.bytes_remaining <= 0) { if ( (rlen = ws_read_header(t, buffer, len, timeout_ms)) < 0) { // If something when wrong then we prepare for reading a new header ws->frame_state.bytes_remaining = 0; return rlen; } // If the new opcode is a control frame and we don't pass it to the app // - try to handle it internally using the application buffer if (ws->frame_state.header_received && (ws->frame_state.opcode & WS_OPCODE_CONTROL_FRAME) && ws->propagate_control_frames == false) { // automatically handle only 0 payload frames and make the transport read to return 0 on success // which might be interpreted as timeouts return ws_handle_control_frame_internal(t, timeout_ms); } if (rlen == 0) { ws->frame_state.bytes_remaining = 0; return 0; // timeout } } if (ws->frame_state.payload_len) { if ( (rlen = ws_read_payload(t, buffer, len, timeout_ms)) <= 0) { ESP_LOGE(TAG, "Error reading payload data"); ws->frame_state.bytes_remaining = 0; return rlen; } } return rlen; } static int ws_poll_read(esp_transport_handle_t t, int timeout_ms) { transport_ws_t *ws = esp_transport_get_context_data(t); return esp_transport_poll_read(ws->parent, timeout_ms); } static int ws_poll_write(esp_transport_handle_t t, int timeout_ms) { transport_ws_t *ws = esp_transport_get_context_data(t); return esp_transport_poll_write(ws->parent, timeout_ms);; } static int ws_close(esp_transport_handle_t t) { transport_ws_t *ws = esp_transport_get_context_data(t); return esp_transport_close(ws->parent); } static esp_err_t ws_destroy(esp_transport_handle_t t) { transport_ws_t *ws = esp_transport_get_context_data(t); free(ws->buffer); free(ws->path); free(ws->sub_protocol); free(ws->user_agent); free(ws->headers); free(ws); return 0; } static esp_err_t internal_esp_transport_ws_set_path(esp_transport_handle_t t, const char *path) { if (t == NULL) { return ESP_ERR_INVALID_ARG; } transport_ws_t *ws = esp_transport_get_context_data(t); if (ws->path) { free(ws->path); } if (path == NULL) { ws->path = NULL; return ESP_OK; } ws->path = strdup(path); if (ws->path == NULL) { return ESP_ERR_NO_MEM; } return ESP_OK; } void esp_transport_ws_set_path(esp_transport_handle_t t, const char *path) { esp_err_t err = internal_esp_transport_ws_set_path(t, path); if (err != ESP_OK) { ESP_LOGE(TAG, "esp_transport_ws_set_path has internally failed with err=%d", err); } } static int ws_get_socket(esp_transport_handle_t t) { if (t) { transport_ws_t *ws = t->data; if (ws && ws->parent && ws->parent->_get_socket) { return ws->parent->_get_socket(ws->parent); } } return -1; } esp_transport_handle_t esp_transport_ws_init(esp_transport_handle_t parent_handle) { esp_transport_handle_t t = esp_transport_init(); if (t == NULL) { return NULL; } transport_ws_t *ws = calloc(1, sizeof(transport_ws_t)); ESP_TRANSPORT_MEM_CHECK(TAG, ws, return NULL); ws->parent = parent_handle; ws->path = strdup("/"); ESP_TRANSPORT_MEM_CHECK(TAG, ws->path, { free(ws); esp_transport_destroy(t); return NULL; }); ws->buffer = malloc(WS_BUFFER_SIZE); ESP_TRANSPORT_MEM_CHECK(TAG, ws->buffer, { free(ws->path); free(ws); esp_transport_destroy(t); return NULL; }); esp_transport_set_func(t, ws_connect, ws_read, ws_write, ws_close, ws_poll_read, ws_poll_write, ws_destroy); // webocket underlying transfer is the payload transfer handle esp_transport_set_parent_transport_func(t, ws_get_payload_transport_handle); esp_transport_set_context_data(t, ws); t->_get_socket = ws_get_socket; return t; } esp_err_t esp_transport_ws_set_subprotocol(esp_transport_handle_t t, const char *sub_protocol) { if (t == NULL) { return ESP_ERR_INVALID_ARG; } transport_ws_t *ws = esp_transport_get_context_data(t); if (ws->sub_protocol) { free(ws->sub_protocol); } if (sub_protocol == NULL) { ws->sub_protocol = NULL; return ESP_OK; } ws->sub_protocol = strdup(sub_protocol); if (ws->sub_protocol == NULL) { return ESP_ERR_NO_MEM; } return ESP_OK; } esp_err_t esp_transport_ws_set_user_agent(esp_transport_handle_t t, const char *user_agent) { if (t == NULL) { return ESP_ERR_INVALID_ARG; } transport_ws_t *ws = esp_transport_get_context_data(t); if (ws->user_agent) { free(ws->user_agent); } if (user_agent == NULL) { ws->user_agent = NULL; return ESP_OK; } ws->user_agent = strdup(user_agent); if (ws->user_agent == NULL) { return ESP_ERR_NO_MEM; } return ESP_OK; } esp_err_t esp_transport_ws_set_headers(esp_transport_handle_t t, const char *headers) { if (t == NULL) { return ESP_ERR_INVALID_ARG; } transport_ws_t *ws = esp_transport_get_context_data(t); if (ws->headers) { free(ws->headers); } if (headers == NULL) { ws->headers = NULL; return ESP_OK; } ws->headers = strdup(headers); if (ws->headers == NULL) { return ESP_ERR_NO_MEM; } return ESP_OK; } esp_err_t esp_transport_ws_set_config(esp_transport_handle_t t, const esp_transport_ws_config_t *config) { if (t == NULL) { return ESP_ERR_INVALID_ARG; } esp_err_t err = ESP_OK; transport_ws_t *ws = esp_transport_get_context_data(t); if (config->ws_path) { err = internal_esp_transport_ws_set_path(t, config->ws_path); ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;) } if (config->sub_protocol) { err = esp_transport_ws_set_subprotocol(t, config->sub_protocol); ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;) } if (config->user_agent) { err = esp_transport_ws_set_user_agent(t, config->user_agent); ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;) } if (config->headers) { err = esp_transport_ws_set_headers(t, config->headers); ESP_TRANSPORT_ERR_OK_CHECK(TAG, err, return err;) } ws->propagate_control_frames = config->propagate_control_frames; return err; } ws_transport_opcodes_t esp_transport_ws_get_read_opcode(esp_transport_handle_t t) { transport_ws_t *ws = esp_transport_get_context_data(t); if (ws->frame_state.header_received) { // convert the header byte to enum if correctly received return (ws_transport_opcodes_t)ws->frame_state.opcode; } return WS_TRANSPORT_OPCODES_NONE; } int esp_transport_ws_get_read_payload_len(esp_transport_handle_t t) { transport_ws_t *ws = esp_transport_get_context_data(t); return ws->frame_state.payload_len; } static int esp_transport_ws_handle_control_frames(esp_transport_handle_t t, char *buffer, int len, int timeout_ms, bool client_closed) { transport_ws_t *ws = esp_transport_get_context_data(t); // If no new header reception in progress, or not a control frame // just pass 0 -> no need to handle control frames if (ws->frame_state.header_received == false || !(ws->frame_state.opcode & WS_OPCODE_CONTROL_FRAME)) { return 0; } int actual_len; int payload_len = ws->frame_state.payload_len; ESP_LOGD(TAG, "Handling control frame with %d bytes payload", payload_len); if (payload_len > len) { ESP_LOGE(TAG, "Not enough room for processing the payload (need=%d, available=%d)", payload_len, len); ws->frame_state.bytes_remaining = payload_len - len; return -1; } if (ws->frame_state.opcode == WS_OPCODE_PING) { // handle PING frames internally: just send a PONG with the same payload actual_len = _ws_write(t, WS_OPCODE_PONG | WS_FIN, WS_MASK, buffer, payload_len, timeout_ms); if (actual_len != payload_len) { ESP_LOGE(TAG, "PONG send failed (payload_len=%d, written_len=%d)", payload_len, actual_len); return -1; } ESP_LOGD(TAG, "PONG sent correctly (payload_len=%d)", payload_len); // control frame handled correctly, reset the flag indicating new header received ws->frame_state.header_received = false; return 0; } else if (ws->frame_state.opcode == WS_OPCODE_CLOSE) { // handle CLOSE by the server: send a zero payload frame if (buffer && payload_len > 0) { // if some payload, print out the status code uint16_t *code_network_order = (uint16_t *) buffer; ESP_LOGI(TAG, "Got CLOSE frame with status code=%u", ntohs(*code_network_order)); } if (client_closed == false) { // Only echo the closing frame if not initiated by the client if (_ws_write(t, WS_OPCODE_CLOSE | WS_FIN, WS_MASK, NULL,0, timeout_ms) < 0) { ESP_LOGE(TAG, "Sending CLOSE frame with 0 payload failed"); return -1; } ESP_LOGD(TAG, "CLOSE frame with no payload sent correctly"); } // control frame handled correctly, reset the flag indicating new header received ws->frame_state.header_received = false; int ret = esp_transport_ws_poll_connection_closed(t, timeout_ms); if (ret == 0) { ESP_LOGW(TAG, "Connection cannot be terminated gracefully within timeout=%d", timeout_ms); return -1; } if (ret < 0) { ESP_LOGW(TAG, "Connection terminated while waiting for clean TCP close"); return -1; } ESP_LOGI(TAG, "Connection terminated gracefully"); return 1; } else if (ws->frame_state.opcode == WS_OPCODE_PONG) { // handle PONG: just indicate return code ESP_LOGD(TAG, "Received PONG frame with payload=%d", payload_len); // control frame handled correctly, reset the flag indicating new header received ws->frame_state.header_received = false; return 2; } return 0; } int esp_transport_ws_poll_connection_closed(esp_transport_handle_t t, int timeout_ms) { struct timeval timeout; int sock = esp_transport_get_socket(t); fd_set readset; fd_set errset; FD_ZERO(&readset); FD_ZERO(&errset); FD_SET(sock, &readset); FD_SET(sock, &errset); int ret = select(sock + 1, &readset, NULL, &errset, esp_transport_utils_ms_to_timeval(timeout_ms, &timeout)); if (ret > 0) { if (FD_ISSET(sock, &readset)) { uint8_t buffer; if (recv(sock, &buffer, 1, MSG_PEEK) <= 0) { // socket is readable, but reads zero bytes -- connection cleanly closed by FIN flag return 1; } ESP_LOGW(TAG, "esp_transport_ws_poll_connection_closed: unexpected data readable on socket=%d", sock); } else if (FD_ISSET(sock, &errset)) { int sock_errno = 0; uint32_t optlen = sizeof(sock_errno); getsockopt(sock, SOL_SOCKET, SO_ERROR, &sock_errno, &optlen); ESP_LOGD(TAG, "esp_transport_ws_poll_connection_closed select error %d, errno = %s, fd = %d", sock_errno, strerror(sock_errno), sock); if (sock_errno == ENOTCONN || sock_errno == ECONNRESET || sock_errno == ECONNABORTED) { // the three err codes above might be caused by connection termination by RTS flag // which we still assume as expected closing sequence of ws-transport connection return 1; } ESP_LOGE(TAG, "esp_transport_ws_poll_connection_closed: unexpected errno=%d on socket=%d", sock_errno, sock); } return -1; // indicates error: socket unexpectedly reads an actual data, or unexpected errno code } return ret; }