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OVMS3-idf/components/tcp_transport/transport_ws.c
David Cermak db121a56e1 tcp_transport: modified ws_read to read payload directly to the read buffer and separately from header bytes 
Previous version read all data to the buffer including header which reduced maximum payload read. This version uses a local array to receive header and reads payload bytes to the buffer
2019-05-27 16:31:24 +02:00

314 lines
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C
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#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <sys/random.h>
#include "esp_log.h"
#include "esp_transport.h"
#include "esp_transport_tcp.h"
#include "esp_transport_ws.h"
#include "esp_transport_utils.h"
#include "transport_strcasestr.h"
#include "mbedtls/base64.h"
#include "mbedtls/sha1.h"
static const char *TAG = "TRANSPORT_WS";
#define DEFAULT_WS_BUFFER (1024)
#define WS_FIN 0x80
#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
// Second byte
#define WS_MASK 0x80
#define WS_SIZE16 126
#define WS_SIZE64 127
#define MAX_WEBSOCKET_HEADER_SIZE 10
#define WS_RESPONSE_OK 101
typedef struct {
char *path;
char *buffer;
esp_transport_handle_t parent;
} transport_ws_t;
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);
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 = transport_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 connect to the server");
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};
size_t outlen = 0;
mbedtls_base64_encode(client_key, sizeof(client_key), &outlen, random_key, sizeof(random_key));
int len = snprintf(ws->buffer, DEFAULT_WS_BUFFER,
"GET %s HTTP/1.1\r\n"
"Connection: Upgrade\r\n"
"Host: %s:%d\r\n"
"Upgrade: websocket\r\n"
"Sec-WebSocket-Version: 13\r\n"
"Sec-WebSocket-Protocol: mqtt\r\n"
"Sec-WebSocket-Key: %s\r\n"
"User-Agent: ESP32 Websocket Client\r\n\r\n",
ws->path,
host, port,
client_key);
if (len <= 0 || len >= DEFAULT_WS_BUFFER) {
ESP_LOGE(TAG, "Error in request generation, %d", len);
return -1;
}
ESP_LOGD(TAG, "Write upgrate 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, DEFAULT_WS_BUFFER - 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 < DEFAULT_WS_BUFFER);
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 mbedtls_sha1_ret() 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);
mbedtls_sha1_ret(expected_server_text, key_len, expected_server_sha1);
mbedtls_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, const char *buff, int len, int timeout_ms)
{
transport_ws_t *ws = esp_transport_get_context_data(t);
char ws_header[MAX_WEBSOCKET_HEADER_SIZE];
char *mask;
int header_len = 0, i;
char *buffer = (char *)buff;
int poll_write;
if ((poll_write = esp_transport_poll_write(ws->parent, timeout_ms)) <= 0) {
return poll_write;
}
ws_header[header_len++] = WS_OPCODE_BINARY | WS_FIN;
// NOTE: no support for > 16-bit sized messages
if (len > 125) {
ws_header[header_len++] = WS_SIZE16 | WS_MASK;
ws_header[header_len++] = (uint8_t)(len >> 8);
ws_header[header_len++] = (uint8_t)(len & 0xFF);
} else {
ws_header[header_len++] = (uint8_t)(len | WS_MASK);
}
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;
}
return esp_transport_write(ws->parent, buffer, len, timeout_ms);
}
static int ws_read(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, opcode, mask, *mask_key = NULL;
int rlen;
int poll_read;
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;
if ((rlen = esp_transport_read(ws->parent, data_ptr, header, timeout_ms)) <= 0) {
ESP_LOGE(TAG, "Error read data");
return rlen;
}
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", 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 (payload_len > len) {
ESP_LOGD(TAG, "Actual data to receive (%d) are longer than ws buffer (%d)", payload_len, len);
payload_len = len;
}
// Then receive and process payload
if ((rlen = esp_transport_read(ws->parent, buffer, payload_len, timeout_ms)) <= 0) {
ESP_LOGE(TAG, "Error read data");
return rlen;
}
if (mask) {
mask_key = buffer;
data_ptr = buffer + 4;
for (int i = 0; i < payload_len; i++) {
buffer[i] = (data_ptr[i] ^ mask_key[i % 4]);
}
}
return payload_len;
}
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);
return 0;
}
void esp_transport_ws_set_path(esp_transport_handle_t t, const char *path)
{
transport_ws_t *ws = esp_transport_get_context_data(t);
ws->path = realloc(ws->path, strlen(path) + 1);
strcpy(ws->path, path);
}
esp_transport_handle_t esp_transport_ws_init(esp_transport_handle_t parent_handle)
{
esp_transport_handle_t t = esp_transport_init();
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, return NULL);
ws->buffer = malloc(DEFAULT_WS_BUFFER);
ESP_TRANSPORT_MEM_CHECK(TAG, ws->buffer, {
free(ws->path);
free(ws);
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);
return t;
}
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