2 * libwebsockets - small server side websockets and web server implementation
4 * Copyright (C) 2010-2013 Andy Green <andy@warmcat.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation:
9 * version 2.1 of the License.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
22 #include "private-libwebsockets.h"
28 #ifdef LWS_BUILTIN_GETIFADDRS
29 #include <getifaddrs.h>
34 #include <sys/socket.h>
38 #ifdef LWS_OPENSSL_SUPPORT
39 extern int openssl_websocket_private_data_index;
42 int lws_client_socket_service(struct libwebsocket_context *context, struct libwebsocket *wsi, struct pollfd *pollfd)
49 #ifdef LWS_OPENSSL_SUPPORT
50 char ssl_err_buf[512];
55 case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
57 /* handle proxy hung up on us */
59 if (pollfd->revents & (POLLERR | POLLHUP)) {
61 lwsl_warn("Proxy connection %p (fd=%d) dead\n",
62 (void *)wsi, pollfd->fd);
64 libwebsocket_close_and_free_session(context, wsi,
65 LWS_CLOSE_STATUS_NOSTATUS);
69 n = recv(wsi->sock, pkt, sizeof pkt, 0);
71 libwebsocket_close_and_free_session(context, wsi,
72 LWS_CLOSE_STATUS_NOSTATUS);
73 lwsl_err("ERROR reading from proxy socket\n");
78 if (strcmp(pkt, "HTTP/1.0 200 ") != 0) {
79 libwebsocket_close_and_free_session(context, wsi,
80 LWS_CLOSE_STATUS_NOSTATUS);
81 lwsl_err("ERROR from proxy: %s\n", pkt);
85 /* clear his proxy connection timeout */
87 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
91 case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
94 * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
95 * timeout protection set in client-handshake.c
98 #ifdef LWS_OPENSSL_SUPPORT
101 * take care of our libwebsocket_callback_on_writable
102 * happening at a time when there's no real connection yet
105 pollfd->events &= ~POLLOUT;
107 /* external POLL support via protocol 0 */
108 context->protocols[0].callback(context, wsi,
109 LWS_CALLBACK_CLEAR_MODE_POLL_FD,
110 (void *)(long)wsi->sock, NULL, POLLOUT);
112 /* we can retry this... so just cook the SSL BIO the first time */
114 if (wsi->use_ssl && !wsi->ssl) {
116 wsi->ssl = SSL_new(context->ssl_client_ctx);
117 wsi->client_bio = BIO_new_socket(wsi->sock,
119 SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
121 SSL_set_ex_data(wsi->ssl,
122 openssl_websocket_private_data_index,
127 n = SSL_connect(wsi->ssl);
130 n = SSL_get_error(wsi->ssl, n);
132 if (n == SSL_ERROR_WANT_READ ||
133 n == SSL_ERROR_WANT_WRITE) {
135 * wants us to retry connect due to state of the
136 * underlying ssl layer... but since it may be
137 * stalled on blocked write, no incoming data may
138 * arrive to trigger the retry. Force (possibly
139 * many if the SSL state persists in returning the
140 * condition code, but other sockets are getting
141 * serviced inbetweentimes) us to get called back
145 lwsl_info("SSL_connect -> SSL_ERROR_WANT_... retrying\n");
146 libwebsocket_callback_on_writable(context, wsi);
148 return 0; /* no error */
155 * retry if new data comes until we
156 * run into the connection timeout or win
159 lwsl_err("SSL connect error %s\n",
160 ERR_error_string(ERR_get_error(),
165 n = SSL_get_verify_result(wsi->ssl);
166 if ((n != X509_V_OK) && (
167 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
168 wsi->use_ssl != 2)) {
170 lwsl_err("server's cert didn't "
171 "look good %d\n", n);
172 libwebsocket_close_and_free_session(context,
173 wsi, LWS_CLOSE_STATUS_NOSTATUS);
180 p = libwebsockets_generate_client_handshake(context, wsi, p);
182 lwsl_err("Failed to generate handshake for client, closing it\n");
183 libwebsocket_close_and_free_session(context, wsi,
184 LWS_CLOSE_STATUS_NOSTATUS);
188 /* send our request to the server */
190 #ifdef LWS_OPENSSL_SUPPORT
192 n = SSL_write(wsi->ssl, pkt, p - pkt);
195 n = send(wsi->sock, pkt, p - pkt, 0);
198 lwsl_debug("ERROR writing to client socket\n");
199 libwebsocket_close_and_free_session(context, wsi,
200 LWS_CLOSE_STATUS_NOSTATUS);
204 wsi->parser_state = WSI_TOKEN_NAME_PART;
205 wsi->lextable_pos = 0;
206 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
207 libwebsocket_set_timeout(wsi,
208 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE, AWAITING_TIMEOUT);
212 case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
214 /* handle server hung up on us */
216 if (pollfd->revents & (POLLERR | POLLHUP)) {
218 lwsl_debug("Server connection %p (fd=%d) dead\n",
219 (void *)wsi, pollfd->fd);
225 /* interpret the server response */
228 * HTTP/1.1 101 Switching Protocols
230 * Connection: Upgrade
231 * Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
232 * Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
233 * Sec-WebSocket-Protocol: chat
237 * we have to take some care here to only take from the
238 * socket bytewise. The browser may (and has been seen to
239 * in the case that onopen() performs websocket traffic)
240 * coalesce both handshake response and websocket traffic
241 * in one packet, since at that point the connection is
242 * definitively ready from browser pov.
246 while (wsi->parser_state != WSI_PARSING_COMPLETE && len > 0) {
247 #ifdef LWS_OPENSSL_SUPPORT
249 len = SSL_read(wsi->ssl, &c, 1);
252 len = recv(wsi->sock, &c, 1, 0);
254 libwebsocket_parse(wsi, c);
258 * hs may also be coming in multiple packets, there is a 5-sec
259 * libwebsocket timeout still active here too, so if parsing did
260 * not complete just wait for next packet coming in this state
263 if (wsi->parser_state != WSI_PARSING_COMPLETE)
267 * otherwise deal with the handshake. If there's any
268 * packet traffic already arrived we'll trigger poll() again
269 * right away and deal with it that way
272 return lws_client_interpret_server_handshake(context, wsi);
276 free(wsi->c_protocol);
277 libwebsocket_close_and_free_session(context, wsi,
278 LWS_CLOSE_STATUS_NOSTATUS);
281 case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
282 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
285 case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
286 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
297 * In-place str to lower case
310 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
311 struct libwebsocket *wsi)
315 #ifndef LWS_NO_EXTENSIONS
317 struct libwebsocket_extension *ext;
325 * well, what the server sent looked reasonable for syntax.
326 * Now let's confirm it sent all the necessary headers
329 lwsl_parser("WSI_TOKEN_HTTP: %d\n",
330 wsi->utf8_token[WSI_TOKEN_HTTP].token_len);
331 lwsl_parser("WSI_TOKEN_UPGRADE: %d\n",
332 wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len);
333 lwsl_parser("WSI_TOKEN_CONNECTION: %d\n",
334 wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len);
335 lwsl_parser("WSI_TOKEN_ACCEPT: %d\n",
336 wsi->utf8_token[WSI_TOKEN_ACCEPT].token_len);
337 lwsl_parser("WSI_TOKEN_NONCE: %d\n",
338 wsi->utf8_token[WSI_TOKEN_NONCE].token_len);
339 lwsl_parser("WSI_TOKEN_PROTOCOL: %d\n",
340 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len);
343 strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
344 if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
345 lwsl_warn("libwebsocket_client_handshake "
346 "server sent bad HTTP response '%s'\n",
347 wsi->utf8_token[WSI_TOKEN_HTTP].token);
351 strtolower(wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
352 if (strcmp(wsi->utf8_token[WSI_TOKEN_UPGRADE].token,
354 lwsl_warn("libwebsocket_client_handshake server "
355 "sent bad Upgrade header '%s'\n",
356 wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
360 strtolower(wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
361 if (strcmp(wsi->utf8_token[WSI_TOKEN_CONNECTION].token,
363 lwsl_warn("libwebsocket_client_handshake server "
364 "sent bad Connection hdr '%s'\n",
365 wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
369 pc = wsi->c_protocol;
371 lwsl_parser("lws_client_interpret_server_handshake: "
372 "NULL c_protocol\n");
374 lwsl_parser("lws_client_interpret_server_handshake: "
375 "cPprotocol='%s'\n", pc);
378 * confirm the protocol the server wants to talk was in the list
379 * of protocols we offered
382 if (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len) {
384 lwsl_info("lws_client_interpret_server_handshake "
385 "WSI_TOKEN_PROTOCOL is null\n");
387 * no protocol name to work from,
388 * default to first protocol
390 wsi->protocol = &context->protocols[0];
391 wsi->c_callback = wsi->protocol->callback;
392 free(wsi->c_protocol);
394 goto check_extensions;
397 while (*pc && !okay) {
398 if ((!strncmp(pc, wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
399 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len)) &&
400 (pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == ',' ||
401 pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == '\0')) {
405 while (*pc && *pc != ',')
407 while (*pc && *pc != ' ')
411 /* done with him now */
414 free(wsi->c_protocol);
417 lwsl_err("libwebsocket_client_handshake server "
418 "sent bad protocol '%s'\n",
419 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
424 * identify the selected protocol struct and set it
427 wsi->protocol = NULL;
428 while (context->protocols[n].callback && !wsi->protocol) { /* Stop after finding first one?? */
429 if (strcmp(wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
430 context->protocols[n].name) == 0) {
431 wsi->protocol = &context->protocols[n];
432 wsi->c_callback = wsi->protocol->callback;
437 if (wsi->protocol == NULL) {
438 lwsl_err("libwebsocket_client_handshake server "
439 "requested protocol '%s', which we "
440 "said we supported but we don't!\n",
441 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
447 #ifndef LWS_NO_EXTENSIONS
448 /* instantiate the accepted extensions */
450 if (!wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token_len) {
451 lwsl_ext("no client extenstions allowed by server\n");
456 * break down the list of server accepted extensions
457 * and go through matching them or identifying bogons
460 c = wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token;
464 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
466 if (n < sizeof(ext_name) - 1)
479 /* check we actually support it */
481 lwsl_ext("checking client ext %s\n", ext_name);
484 ext = wsi->protocol->owning_server->extensions;
485 while (ext && ext->callback) {
487 if (strcmp(ext_name, ext->name)) {
494 lwsl_ext("instantiating client ext %s\n", ext_name);
496 /* instantiate the extension on this conn */
498 wsi->active_extensions_user[
499 wsi->count_active_extensions] =
500 malloc(ext->per_session_data_size);
501 if (wsi->active_extensions_user[
502 wsi->count_active_extensions] == NULL) {
503 lwsl_err("Out of mem\n");
506 memset(wsi->active_extensions_user[
507 wsi->count_active_extensions], 0,
508 ext->per_session_data_size);
509 wsi->active_extensions[
510 wsi->count_active_extensions] = ext;
512 /* allow him to construct his context */
514 ext->callback(wsi->protocol->owning_server,
516 LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
517 wsi->active_extensions_user[
518 wsi->count_active_extensions],
521 wsi->count_active_extensions++;
527 lwsl_warn("Server said we should use"
528 "an unknown extension '%s'!\n", ext_name);
539 * Confirm his accept token is the one we precomputed
542 if (strcmp(wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
543 wsi->initial_handshake_hash_base64)) {
544 lwsl_warn("libwebsocket_client_handshake server "
545 "sent bad ACCEPT '%s' vs computed '%s'\n",
546 wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
547 wsi->initial_handshake_hash_base64);
551 /* allocate the per-connection user memory (if any) */
552 if (wsi->protocol->per_session_data_size &&
553 !libwebsocket_ensure_user_space(wsi))
556 /* clear his proxy connection timeout */
558 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
560 /* mark him as being alive */
562 wsi->state = WSI_STATE_ESTABLISHED;
563 wsi->mode = LWS_CONNMODE_WS_CLIENT;
565 lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
567 /* call him back to inform him he is up */
569 wsi->protocol->callback(context, wsi,
570 LWS_CALLBACK_CLIENT_ESTABLISHED,
571 wsi->user_space, NULL, 0);
572 #ifndef LWS_NO_EXTENSIONS
574 * inform all extensions, not just active ones since they
578 ext = context->extensions;
580 while (ext && ext->callback) {
582 for (n = 0; n < wsi->count_active_extensions; n++)
583 if (wsi->active_extensions[n] == ext)
584 v = wsi->active_extensions_user[n];
586 ext->callback(context, ext, wsi,
587 LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
596 free(wsi->c_protocol);
599 if (wsi->c_callback) wsi->c_callback(context, wsi,
600 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
603 libwebsocket_close_and_free_session(context, wsi,
604 LWS_CLOSE_STATUS_NOSTATUS); // But this should be LWS_CLOSE_STATUS_PROTOCOL_ERR
611 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
612 struct libwebsocket *wsi, char *pkt)
617 #ifndef LWS_NO_EXTENSIONS
618 struct libwebsocket_extension *ext;
619 struct libwebsocket_extension *ext1;
622 unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
623 MAX_BROADCAST_PAYLOAD + LWS_SEND_BUFFER_POST_PADDING];
624 static const char magic_websocket_guid[] =
625 "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
628 * create the random key
631 n = libwebsockets_get_random(context, hash, 16);
633 lwsl_err("Unable to read from random dev %s\n",
634 SYSTEM_RANDOM_FILEPATH);
640 free(wsi->c_protocol);
641 libwebsocket_close_and_free_session(context, wsi,
642 LWS_CLOSE_STATUS_NOSTATUS);
646 lws_b64_encode_string(hash, 16, wsi->key_b64,
647 sizeof wsi->key_b64);
650 * 00 example client handshake
652 * GET /socket.io/websocket HTTP/1.1
654 * Connection: Upgrade
655 * Host: 127.0.0.1:9999
656 * Origin: http://127.0.0.1
657 * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7 92 ^
658 * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
659 * Cookie: socketio=websocket
663 * 04 example client handshake
666 * Host: server.example.com
668 * Connection: Upgrade
669 * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
670 * Sec-WebSocket-Origin: http://example.com
671 * Sec-WebSocket-Protocol: chat, superchat
672 * Sec-WebSocket-Version: 4
675 p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
677 p += sprintf(p, "Pragma: no-cache\x0d\x0a"
678 "Cache-Control: no-cache\x0d\x0a");
680 p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
681 p += sprintf(p, "Upgrade: websocket\x0d\x0a"
682 "Connection: Upgrade\x0d\x0a"
683 "Sec-WebSocket-Key: ");
684 strcpy(p, wsi->key_b64);
685 p += strlen(wsi->key_b64);
686 p += sprintf(p, "\x0d\x0a");
688 if (wsi->ietf_spec_revision == 13)
689 p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
691 p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
695 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
698 /* tell the server what extensions we could support */
700 p += sprintf(p, "Sec-WebSocket-Extensions: ");
701 #ifndef LWS_NO_EXTENSIONS
702 ext = context->extensions;
703 while (ext && ext->callback) {
706 ext1 = context->extensions;
708 while (ext1 && ext1->callback) {
709 n |= ext1->callback(context, ext1, wsi,
710 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
711 NULL, (char *)ext->name, 0);
716 if (n) { /* an extension vetos us */
717 lwsl_ext("ext %s vetoed\n", (char *)ext->name);
722 n = context->protocols[0].callback(context, wsi,
723 LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
724 wsi->user_space, (char *)ext->name, 0);
727 * zero return from callback means
728 * go ahead and allow the extension,
729 * it's what we get if the callback is
742 p += sprintf(p, "%s", ext->name);
748 p += sprintf(p, "\x0d\x0a");
750 if (wsi->ietf_spec_revision)
751 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
752 wsi->ietf_spec_revision);
754 /* give userland a chance to append, eg, cookies */
756 context->protocols[0].callback(context, wsi,
757 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
758 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
760 p += sprintf(p, "\x0d\x0a");
762 /* prepare the expected server accept response */
764 strcpy((char *)buf, wsi->key_b64);
765 strcpy((char *)&buf[strlen((char *)buf)], magic_websocket_guid);
767 SHA1(buf, strlen((char *)buf), (unsigned char *)hash);
769 lws_b64_encode_string(hash, 20,
770 wsi->initial_handshake_hash_base64,
771 sizeof wsi->initial_handshake_hash_base64);
773 /* done with these now */