291 lines
9.5 KiB
C
291 lines
9.5 KiB
C
#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <sys/random.h>
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#include "esp_log.h"
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#include "esp_transport.h"
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#include "esp_transport_tcp.h"
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#include "esp_transport_ws.h"
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#include "esp_transport_utils.h"
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#include "mbedtls/base64.h"
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#include "mbedtls/sha1.h"
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static const char *TAG = "TRANSPORT_WS";
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#define DEFAULT_WS_BUFFER (1024)
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#define WS_FIN 0x80
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#define WS_OPCODE_TEXT 0x01
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#define WS_OPCODE_BINARY 0x02
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#define WS_OPCODE_CLOSE 0x08
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#define WS_OPCODE_PING 0x09
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#define WS_OPCODE_PONG 0x0a
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// Second byte
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#define WS_MASK 0x80
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#define WS_SIZE16 126
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#define WS_SIZE64 127
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#define MAX_WEBSOCKET_HEADER_SIZE 10
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#define WS_RESPONSE_OK 101
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typedef struct {
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char *path;
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char *buffer;
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esp_transport_handle_t parent;
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} transport_ws_t;
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static esp_transport_handle_t ws_get_payload_transport_handle(esp_transport_handle_t t)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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return ws->parent;
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}
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static char *trimwhitespace(const char *str)
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{
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char *end;
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// Trim leading space
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while (isspace((unsigned char)*str)) str++;
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if (*str == 0) {
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return (char *)str;
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}
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// Trim trailing space
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end = (char *)(str + strlen(str) - 1);
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while (end > str && isspace((unsigned char)*end)) end--;
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// Write new null terminator
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*(end + 1) = 0;
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return (char *)str;
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}
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static char *get_http_header(const char *buffer, const char *key)
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{
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char *found = strstr(buffer, key);
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if (found) {
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found += strlen(key);
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char *found_end = strstr(found, "\r\n");
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if (found_end) {
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found_end[0] = 0;//terminal string
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return trimwhitespace(found);
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}
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}
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return NULL;
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}
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static int ws_connect(esp_transport_handle_t t, const char *host, int port, int timeout_ms)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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if (esp_transport_connect(ws->parent, host, port, timeout_ms) < 0) {
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ESP_LOGE(TAG, "Error connect to ther server");
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}
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unsigned char random_key[16];
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getrandom(random_key, sizeof(random_key), 0);
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// Size of base64 coded string is equal '((input_size * 4) / 3) + (input_size / 96) + 6' including Z-term
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unsigned char client_key[28] = {0};
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size_t outlen = 0;
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mbedtls_base64_encode(client_key, sizeof(client_key), &outlen, random_key, sizeof(random_key));
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int len = snprintf(ws->buffer, DEFAULT_WS_BUFFER,
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"GET %s HTTP/1.1\r\n"
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"Connection: Upgrade\r\n"
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"Host: %s:%d\r\n"
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"Upgrade: websocket\r\n"
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"Sec-WebSocket-Version: 13\r\n"
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"Sec-WebSocket-Protocol: mqtt\r\n"
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"Sec-WebSocket-Key: %s\r\n"
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"User-Agent: ESP32 MQTT Client\r\n\r\n",
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ws->path,
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host, port,
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client_key);
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if (len <= 0 || len >= DEFAULT_WS_BUFFER) {
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ESP_LOGE(TAG, "Error in request generation, %d", len);
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return -1;
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}
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ESP_LOGD(TAG, "Write upgrate request\r\n%s", ws->buffer);
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if (esp_transport_write(ws->parent, ws->buffer, len, timeout_ms) <= 0) {
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ESP_LOGE(TAG, "Error write Upgrade header %s", ws->buffer);
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return -1;
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}
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if ((len = esp_transport_read(ws->parent, ws->buffer, DEFAULT_WS_BUFFER, timeout_ms)) <= 0) {
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ESP_LOGE(TAG, "Error read response for Upgrade header %s", ws->buffer);
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return -1;
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}
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char *server_key = get_http_header(ws->buffer, "Sec-WebSocket-Accept:");
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if (server_key == NULL) {
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ESP_LOGE(TAG, "Sec-WebSocket-Accept not found");
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return -1;
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}
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// See mbedtls_sha1_ret() arg size
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unsigned char expected_server_sha1[20];
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// Size of base64 coded string see above
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unsigned char expected_server_key[33] = {0};
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// If you are interested, see https://tools.ietf.org/html/rfc6455
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const char expected_server_magic[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
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unsigned char expected_server_text[sizeof(client_key) + sizeof(expected_server_magic) + 1];
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strcpy((char*)expected_server_text, (char*)client_key);
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strcat((char*)expected_server_text, expected_server_magic);
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size_t key_len = strlen((char*)expected_server_text);
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mbedtls_sha1_ret(expected_server_text, key_len, expected_server_sha1);
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mbedtls_base64_encode(expected_server_key, sizeof(expected_server_key), &outlen, expected_server_sha1, sizeof(expected_server_sha1));
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expected_server_key[ (outlen < sizeof(expected_server_key)) ? outlen : (sizeof(expected_server_key) - 1) ] = 0;
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ESP_LOGD(TAG, "server key=%s, send_key=%s, expected_server_key=%s", (char *)server_key, (char*)client_key, expected_server_key);
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if (strcmp((char*)expected_server_key, (char*)server_key) != 0) {
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ESP_LOGE(TAG, "Invalid websocket key");
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return -1;
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}
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return 0;
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}
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static int ws_write(esp_transport_handle_t t, const char *buff, int len, int timeout_ms)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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char ws_header[MAX_WEBSOCKET_HEADER_SIZE];
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char *mask;
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int header_len = 0, i;
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char *buffer = (char *)buff;
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int poll_write;
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if ((poll_write = esp_transport_poll_write(ws->parent, timeout_ms)) <= 0) {
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return poll_write;
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}
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ws_header[header_len++] = WS_OPCODE_BINARY | WS_FIN;
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// NOTE: no support for > 16-bit sized messages
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if (len > 125) {
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ws_header[header_len++] = WS_SIZE16 | WS_MASK;
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ws_header[header_len++] = (uint8_t)(len >> 8);
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ws_header[header_len++] = (uint8_t)(len & 0xFF);
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} else {
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ws_header[header_len++] = (uint8_t)(len | WS_MASK);
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}
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mask = &ws_header[header_len];
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getrandom(ws_header + header_len, 4, 0);
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header_len += 4;
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for (i = 0; i < len; ++i) {
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buffer[i] = (buffer[i] ^ mask[i % 4]);
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}
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if (esp_transport_write(ws->parent, ws_header, header_len, timeout_ms) != header_len) {
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ESP_LOGE(TAG, "Error write header");
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return -1;
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}
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return esp_transport_write(ws->parent, buffer, len, timeout_ms);
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}
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static int ws_read(esp_transport_handle_t t, char *buffer, int len, int timeout_ms)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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int payload_len;
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int payload_len_buff = len;
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char *data_ptr = buffer, opcode, mask, *mask_key = NULL;
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int rlen;
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int poll_read;
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if ((poll_read = esp_transport_poll_read(ws->parent, timeout_ms)) <= 0) {
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return poll_read;
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}
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if ((rlen = esp_transport_read(ws->parent, buffer, len, timeout_ms)) <= 0) {
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ESP_LOGE(TAG, "Error read data");
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return rlen;
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}
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opcode = (*data_ptr & 0x0F);
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data_ptr ++;
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mask = ((*data_ptr >> 7) & 0x01);
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payload_len = (*data_ptr & 0x7F);
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data_ptr++;
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ESP_LOGD(TAG, "Opcode: %d, mask: %d, len: %d\r\n", opcode, mask, payload_len);
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if (payload_len == 126) {
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// headerLen += 2;
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payload_len = data_ptr[0] << 8 | data_ptr[1];
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payload_len_buff = len - 4;
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data_ptr += 2;
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} else if (payload_len == 127) {
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// headerLen += 8;
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if (data_ptr[0] != 0 || data_ptr[1] != 0 || data_ptr[2] != 0 || data_ptr[3] != 0) {
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// really too big!
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payload_len = 0xFFFFFFFF;
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} else {
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payload_len = data_ptr[4] << 24 | data_ptr[5] << 16 | data_ptr[6] << 8 | data_ptr[7];
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}
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data_ptr += 8;
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payload_len_buff = len - 10;
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}
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if (payload_len > payload_len_buff) {
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ESP_LOGD(TAG, "Actual data received (%d) are longer than mqtt buffer (%d)", payload_len, payload_len_buff);
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payload_len = payload_len_buff;
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}
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if (mask) {
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mask_key = data_ptr;
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data_ptr += 4;
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for (int i = 0; i < payload_len; i++) {
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buffer[i] = (data_ptr[i] ^ mask_key[i % 4]);
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}
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} else {
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memmove(buffer, data_ptr, payload_len);
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}
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return payload_len;
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}
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static int ws_poll_read(esp_transport_handle_t t, int timeout_ms)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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return esp_transport_poll_read(ws->parent, timeout_ms);
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}
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static int ws_poll_write(esp_transport_handle_t t, int timeout_ms)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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return esp_transport_poll_write(ws->parent, timeout_ms);;
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}
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static int ws_close(esp_transport_handle_t t)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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return esp_transport_close(ws->parent);
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}
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static esp_err_t ws_destroy(esp_transport_handle_t t)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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free(ws->buffer);
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free(ws->path);
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free(ws);
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return 0;
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}
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void esp_transport_ws_set_path(esp_transport_handle_t t, const char *path)
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{
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transport_ws_t *ws = esp_transport_get_context_data(t);
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ws->path = realloc(ws->path, strlen(path) + 1);
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strcpy(ws->path, path);
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}
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esp_transport_handle_t esp_transport_ws_init(esp_transport_handle_t parent_handle)
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{
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esp_transport_handle_t t = esp_transport_init();
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transport_ws_t *ws = calloc(1, sizeof(transport_ws_t));
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ESP_TRANSPORT_MEM_CHECK(TAG, ws, return NULL);
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ws->parent = parent_handle;
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ws->path = strdup("/");
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ESP_TRANSPORT_MEM_CHECK(TAG, ws->path, return NULL);
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ws->buffer = malloc(DEFAULT_WS_BUFFER);
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ESP_TRANSPORT_MEM_CHECK(TAG, ws->buffer, {
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free(ws->path);
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free(ws);
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return NULL;
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});
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esp_transport_set_func(t, ws_connect, ws_read, ws_write, ws_close, ws_poll_read, ws_poll_write, ws_destroy, ws_get_payload_transport_handle);
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esp_transport_set_context_data(t, ws);
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return t;
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}
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