lib/client.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2013 Andy Green <andy@warmcat.com>
   5  *
   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.
  10  *
  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.
  15  *
  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,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "private-libwebsockets.h"
  23
  24 #ifdef WIN32
  25 #include <tchar.h>
  26 #include <io.h>
  27 #else
  28 #ifdef LWS_BUILTIN_GETIFADDRS
  29 #include <getifaddrs.h>
  30 #else
  31 #include <ifaddrs.h>
  32 #endif
  33 #include <sys/un.h>
  34 #include <sys/socket.h>
  35 #include <netdb.h>
  36 #endif
  37
  38 #ifdef LWS_OPENSSL_SUPPORT
  39 extern int openssl_websocket_private_data_index;
  40 #endif
  41
  42 int lws_client_socket_service(struct libwebsocket_context *context, struct libwebsocket *wsi, struct pollfd *pollfd)
  43 {
  44         int n;
  45         char pkt[1024];
  46         char *p = &pkt[0];
  47         int len;
  48         char c;
  49 #ifdef LWS_OPENSSL_SUPPORT
  50         char ssl_err_buf[512];
  51 #endif
  52
  53         switch (wsi->mode) {
  54
  55         case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
  56
  57                 /* handle proxy hung up on us */
  58
  59                 if (pollfd->revents & (POLLERR | POLLHUP)) {
  60
  61                         lwsl_warn("Proxy connection %p (fd=%d) dead\n",
  62                                 (void *)wsi, pollfd->fd);
  63
  64                         libwebsocket_close_and_free_session(context, wsi,
  65                                                      LWS_CLOSE_STATUS_NOSTATUS);
  66                         return 0;
  67                 }
  68
  69                 n = recv(wsi->sock, pkt, sizeof pkt, 0);
  70                 if (n < 0) {
  71                         libwebsocket_close_and_free_session(context, wsi,
  72                                                      LWS_CLOSE_STATUS_NOSTATUS);
  73                         lwsl_err("ERROR reading from proxy socket\n");
  74                         return 0;
  75                 }
  76
  77                 pkt[13] = '\0';
  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);
  82                         return 0;
  83                 }
  84
  85                 /* clear his proxy connection timeout */
  86
  87                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
  88
  89                 /* fallthru */
  90
  91         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
  92
  93                 /*
  94                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
  95                  * timeout protection set in client-handshake.c
  96                  */
  97
  98         #ifdef LWS_OPENSSL_SUPPORT
  99
 100                 /*
 101                  * take care of our libwebsocket_callback_on_writable
 102                  * happening at a time when there's no real connection yet
 103                  */
 104
 105                 pollfd->events &= ~POLLOUT;
 106
 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);
 111
 112                 /* we can retry this... so just cook the SSL BIO the first time */
 113
 114                 if (wsi->use_ssl && !wsi->ssl) {
 115
 116                         wsi->ssl = SSL_new(context->ssl_client_ctx);
 117
 118                         #ifdef USE_CYASSL
 119                         /* CyaSSL does certificate verification differently from OpenSSL.
 120                          * If we should ignore the certificate, we need to set this before
 121                          * SSL_new and SSL_connect is called. Otherwise the connect will
 122                          * simply fail with error code -155 */
 123                         if (wsi->use_ssl == 2) {
 124                                 CyaSSL_set_verify(wsi->ssl, SSL_VERIFY_NONE, NULL);
 125                         }
 126                         #endif // USE_CYASSL
 127
 128                         wsi->client_bio = BIO_new_socket(wsi->sock, BIO_NOCLOSE);
 129
 130                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 131
 132                         #ifdef USE_CYASSL
 133                         CyaSSL_set_using_nonblock(wsi->ssl, 1);
 134                         #else
 135                         BIO_set_nbio(wsi->client_bio, 1); /* nonblocking */
 136                         #endif
 137
 138                         SSL_set_ex_data(wsi->ssl,
 139                                         openssl_websocket_private_data_index,
 140                                                                        context);
 141                 }
 142
 143                 if (wsi->use_ssl) {
 144                         lws_latency_pre(context, wsi);
 145                         n = SSL_connect(wsi->ssl);
 146                         lws_latency(context, wsi, "SSL_connect LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n > 0);
 147
 148                         if (n < 0) {
 149                                 n = SSL_get_error(wsi->ssl, n);
 150
 151                                 if (n == SSL_ERROR_WANT_READ ||
 152                                         n == SSL_ERROR_WANT_WRITE) {
 153                                         /*
 154                                          * wants us to retry connect due to state of the
 155                                          * underlying ssl layer... but since it may be
 156                                          * stalled on blocked write, no incoming data may
 157                                          * arrive to trigger the retry.  Force (possibly
 158                                          * many if the SSL state persists in returning the
 159                                          * condition code, but other sockets are getting
 160                                          * serviced inbetweentimes) us to get called back
 161                                          * when writable.
 162                                          */
 163
 164                                         lwsl_info("SSL_connect -> SSL_ERROR_WANT_... retrying\n");
 165                                         libwebsocket_callback_on_writable(context, wsi);
 166
 167                                         return 0; /* no error */
 168                                 }
 169                                 n = -1;
 170                         }
 171
 172                         if (n <= 0) {
 173                                 /*
 174                                  * retry if new data comes until we
 175                                  * run into the connection timeout or win
 176                                  */
 177
 178                                 lwsl_err("SSL connect error %s\n",
 179                                         ERR_error_string(ERR_get_error(),
 180                                                                   ssl_err_buf));
 181                                 return 0;
 182                         }
 183
 184                         #ifndef USE_CYASSL
 185                         /* See note above about CyaSSL certificate verification */
 186                         lws_latency_pre(context, wsi);
 187                         n = SSL_get_verify_result(wsi->ssl);
 188                         lws_latency(context, wsi, "SSL_get_verify_result LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n > 0);
 189                         if ((n != X509_V_OK) && (
 190                                 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 191                                                            wsi->use_ssl != 2)) {
 192
 193                                 lwsl_err("server's cert didn't "
 194                                                            "look good %d\n", n);
 195                                 libwebsocket_close_and_free_session(context,
 196                                                 wsi, LWS_CLOSE_STATUS_NOSTATUS);
 197                                 return 0;
 198                         }
 199                         #endif // USE_CYASSL
 200                 } else
 201                         wsi->ssl = NULL;
 202         #endif
 203
 204                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 205                 if (p == NULL) {
 206                         lwsl_err("Failed to generate handshake for client, closing it\n");
 207                         libwebsocket_close_and_free_session(context, wsi,
 208                                                      LWS_CLOSE_STATUS_NOSTATUS);
 209                         return 0;
 210                 }
 211
 212                 /* send our request to the server */
 213
 214                 lws_latency_pre(context, wsi);
 215         #ifdef LWS_OPENSSL_SUPPORT
 216                 if (wsi->use_ssl)
 217                         n = SSL_write(wsi->ssl, pkt, p - pkt);
 218                 else
 219         #endif
 220                         n = send(wsi->sock, pkt, p - pkt, 0);
 221                 lws_latency(context, wsi, "send or SSL_write LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n >= 0);
 222
 223                 if (n < 0) {
 224                         lwsl_debug("ERROR writing to client socket\n");
 225                         libwebsocket_close_and_free_session(context, wsi,
 226                                                      LWS_CLOSE_STATUS_NOSTATUS);
 227                         return 0;
 228                 }
 229
 230                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 231                 wsi->u.hdr.lextable_pos = 0;
 232                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 233                 libwebsocket_set_timeout(wsi,
 234                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE, AWAITING_TIMEOUT);
 235
 236                 break;
 237
 238         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 239
 240                 /* handle server hung up on us */
 241
 242                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 243
 244                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 245                                 (void *)wsi, pollfd->fd);
 246
 247                         goto bail3;
 248                 }
 249
 250                 if (!(pollfd->revents & POLLIN))
 251                         goto bail3;
 252
 253                 /* interpret the server response */
 254
 255                 /*
 256                  *  HTTP/1.1 101 Switching Protocols
 257                  *  Upgrade: websocket
 258                  *  Connection: Upgrade
 259                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 260                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 261                  *  Sec-WebSocket-Protocol: chat
 262                  */
 263
 264                 /*
 265                  * we have to take some care here to only take from the
 266                  * socket bytewise.  The browser may (and has been seen to
 267                  * in the case that onopen() performs websocket traffic)
 268                  * coalesce both handshake response and websocket traffic
 269                  * in one packet, since at that point the connection is
 270                  * definitively ready from browser pov.
 271                  */
 272
 273                 len = 1;
 274                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE && len > 0) {
 275 #ifdef LWS_OPENSSL_SUPPORT
 276                         if (wsi->use_ssl) {
 277                                 len = SSL_read(wsi->ssl, &c, 1);
 278                                 if (len < 0) {
 279                                         n = SSL_get_error(wsi->ssl, len);
 280                                         if (n ==  SSL_ERROR_WANT_READ ||
 281                                                         n ==  SSL_ERROR_WANT_WRITE)
 282                                                 return 0;
 283                                 }
 284                         } else
 285 #endif
 286                                 len = recv(wsi->sock, &c, 1, 0);
 287
 288                         if (len < 0)
 289                                 goto bail3;
 290
 291                         libwebsocket_parse(wsi, c);
 292                 }
 293
 294                 /*
 295                  * hs may also be coming in multiple packets, there is a 5-sec
 296                  * libwebsocket timeout still active here too, so if parsing did
 297                  * not complete just wait for next packet coming in this state
 298                  */
 299
 300                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 301                         break;
 302
 303                 /*
 304                  * otherwise deal with the handshake.  If there's any
 305                  * packet traffic already arrived we'll trigger poll() again
 306                  * right away and deal with it that way
 307                  */
 308
 309                 return lws_client_interpret_server_handshake(context, wsi);
 310
 311 bail3:
 312                 if (wsi->c_protocol)
 313                         free(wsi->c_protocol);
 314                 lwsl_info("closing connection at LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY\n");
 315                 libwebsocket_close_and_free_session(context, wsi,
 316                                                     LWS_CLOSE_STATUS_NOSTATUS);
 317                 return 0;
 318
 319         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 320                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 321                 break;
 322
 323         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 324                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 325                 break;
 326         default:
 327                 break;
 328         }
 329
 330         return 0;
 331 }
 332
 333
 334 /*
 335  * In-place str to lower case
 336  */
 337
 338 static void
 339 strtolower(char *s)
 340 {
 341         while (*s) {
 342                 *s = tolower(*s);
 343                 s++;
 344         }
 345 }
 346
 347 int
 348 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 349                 struct libwebsocket *wsi)
 350 {
 351         const char *pc;
 352         int okay = 0;
 353 #ifndef LWS_NO_EXTENSIONS
 354         char ext_name[128];
 355         struct libwebsocket_extension *ext;
 356         void *v;
 357         int more = 1;
 358         const char *c;
 359 #endif
 360         int n;
 361
 362         /*
 363          * well, what the server sent looked reasonable for syntax.
 364          * Now let's confirm it sent all the necessary headers
 365          */
 366 #if 0
 367         lwsl_parser("WSI_TOKEN_HTTP: %d\n",
 368                                     wsi->utf8_token[WSI_TOKEN_HTTP].token_len);
 369         lwsl_parser("WSI_TOKEN_UPGRADE: %d\n",
 370                                  wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len);
 371         lwsl_parser("WSI_TOKEN_CONNECTION: %d\n",
 372                               wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len);
 373         lwsl_parser("WSI_TOKEN_ACCEPT: %d\n",
 374                                   wsi->utf8_token[WSI_TOKEN_ACCEPT].token_len);
 375         lwsl_parser("WSI_TOKEN_NONCE: %d\n",
 376                                    wsi->utf8_token[WSI_TOKEN_NONCE].token_len);
 377         lwsl_parser("WSI_TOKEN_PROTOCOL: %d\n",
 378                                 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len);
 379 #endif
 380
 381         strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
 382         if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
 383                 lwsl_warn("libwebsocket_client_handshake "
 384                                 "server sent bad HTTP response '%s'\n",
 385                                  wsi->utf8_token[WSI_TOKEN_HTTP].token);
 386                 goto bail3;
 387         }
 388
 389         strtolower(wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 390         if (strcmp(wsi->utf8_token[WSI_TOKEN_UPGRADE].token,
 391                                                          "websocket")) {
 392                 lwsl_warn("libwebsocket_client_handshake server "
 393                                 "sent bad Upgrade header '%s'\n",
 394                                   wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 395                 goto bail3;
 396         }
 397
 398         strtolower(wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 399         if (strcmp(wsi->utf8_token[WSI_TOKEN_CONNECTION].token,
 400                                                            "upgrade")) {
 401                 lwsl_warn("libwebsocket_client_handshake server "
 402                                 "sent bad Connection hdr '%s'\n",
 403                            wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 404                 goto bail3;
 405         }
 406
 407         pc = wsi->c_protocol;
 408         if (pc == NULL)
 409                 lwsl_parser("lws_client_interpret_server_handshake: "
 410                                                           "NULL c_protocol\n");
 411         else
 412                 lwsl_parser("lws_client_interpret_server_handshake: "
 413                                                       "cPprotocol='%s'\n", pc);
 414
 415         /*
 416          * confirm the protocol the server wants to talk was in the list
 417          * of protocols we offered
 418          */
 419
 420         if (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len) {
 421
 422                 lwsl_info("lws_client_interpret_server_handshake "
 423                                                "WSI_TOKEN_PROTOCOL is null\n");
 424                 /*
 425                  * no protocol name to work from,
 426                  * default to first protocol
 427                  */
 428                 wsi->protocol = &context->protocols[0];
 429                 wsi->c_callback = wsi->protocol->callback;
 430                 free(wsi->c_protocol);
 431
 432                 goto check_extensions;
 433         }
 434
 435         while (*pc && !okay) {
 436                 if ((!strncmp(pc, wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 437                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len)) &&
 438                  (pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == ',' ||
 439                   pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == '\0')) {
 440                         okay = 1;
 441                         continue;
 442                 }
 443                 while (*pc && *pc != ',')
 444                         pc++;
 445                 while (*pc && *pc != ' ')
 446                         pc++;
 447         }
 448
 449         /* done with him now */
 450
 451         if (wsi->c_protocol)
 452                 free(wsi->c_protocol);
 453
 454         if (!okay) {
 455                 lwsl_err("libwebsocket_client_handshake server "
 456                                         "sent bad protocol '%s'\n",
 457                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 458                 goto bail2;
 459         }
 460
 461         /*
 462          * identify the selected protocol struct and set it
 463          */
 464         n = 0;
 465         wsi->protocol = NULL;
 466         while (context->protocols[n].callback && !wsi->protocol) {  /* Stop after finding first one?? */
 467                 if (strcmp(wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 468                                            context->protocols[n].name) == 0) {
 469                         wsi->protocol = &context->protocols[n];
 470                         wsi->c_callback = wsi->protocol->callback;
 471                 }
 472                 n++;
 473         }
 474
 475         if (wsi->protocol == NULL) {
 476                 lwsl_err("libwebsocket_client_handshake server "
 477                                 "requested protocol '%s', which we "
 478                                 "said we supported but we don't!\n",
 479                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 480                 goto bail2;
 481         }
 482
 483
 484 check_extensions:
 485 #ifndef LWS_NO_EXTENSIONS
 486         /* instantiate the accepted extensions */
 487
 488         if (!wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token_len) {
 489                 lwsl_ext("no client extenstions allowed by server\n");
 490                 goto check_accept;
 491         }
 492
 493         /*
 494          * break down the list of server accepted extensions
 495          * and go through matching them or identifying bogons
 496          */
 497
 498         c = wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token;
 499         n = 0;
 500         while (more) {
 501
 502                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 503                         ext_name[n] = *c++;
 504                         if (n < sizeof(ext_name) - 1)
 505                                 n++;
 506                         continue;
 507                 }
 508                 ext_name[n] = '\0';
 509                 if (!*c)
 510                         more = 0;
 511                 else {
 512                         c++;
 513                         if (!n)
 514                                 continue;
 515                 }
 516
 517                 /* check we actually support it */
 518
 519                 lwsl_ext("checking client ext %s\n", ext_name);
 520
 521                 n = 0;
 522                 ext = wsi->protocol->owning_server->extensions;
 523                 while (ext && ext->callback) {
 524
 525                         if (strcmp(ext_name, ext->name)) {
 526                                 ext++;
 527                                 continue;
 528                         }
 529
 530                         n = 1;
 531
 532                         lwsl_ext("instantiating client ext %s\n", ext_name);
 533
 534                         /* instantiate the extension on this conn */
 535
 536                         wsi->active_extensions_user[
 537                                 wsi->count_active_extensions] =
 538                                          malloc(ext->per_session_data_size);
 539                         if (wsi->active_extensions_user[
 540                                 wsi->count_active_extensions] == NULL) {
 541                                 lwsl_err("Out of mem\n");
 542                                 goto bail2;
 543                         }
 544                         memset(wsi->active_extensions_user[
 545                                 wsi->count_active_extensions], 0,
 546                                                     ext->per_session_data_size);
 547                         wsi->active_extensions[
 548                                   wsi->count_active_extensions] = ext;
 549
 550                         /* allow him to construct his context */
 551
 552                         ext->callback(wsi->protocol->owning_server,
 553                                 ext, wsi,
 554                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 555                                         wsi->active_extensions_user[
 556                                          wsi->count_active_extensions],
 557                                                                    NULL, 0);
 558
 559                         wsi->count_active_extensions++;
 560
 561                         ext++;
 562                 }
 563
 564                 if (n == 0) {
 565                         lwsl_warn("Server said we should use"
 566                                   "an unknown extension '%s'!\n", ext_name);
 567                         goto bail2;
 568                 }
 569
 570                 n = 0;
 571         }
 572
 573 check_accept:
 574 #endif
 575
 576         /*
 577          * Confirm his accept token is the one we precomputed
 578          */
 579
 580         if (strcmp(wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 581                                   wsi->u.hdr.initial_handshake_hash_base64)) {
 582                 lwsl_warn("libwebsocket_client_handshake server "
 583                         "sent bad ACCEPT '%s' vs computed '%s'\n",
 584                         wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 585                                         wsi->u.hdr.initial_handshake_hash_base64);
 586                 goto bail2;
 587         }
 588
 589         /* allocate the per-connection user memory (if any) */
 590         if (wsi->protocol->per_session_data_size &&
 591                                           !libwebsocket_ensure_user_space(wsi))
 592                 goto bail2;
 593
 594         /* clear his proxy connection timeout */
 595
 596         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 597
 598         /* mark him as being alive */
 599
 600         wsi->state = WSI_STATE_ESTABLISHED;
 601         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 602
 603         /* union transition */
 604         memset(&wsi->u, 0, sizeof wsi->u);
 605
 606         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 607
 608         /* call him back to inform him he is up */
 609
 610         wsi->protocol->callback(context, wsi,
 611                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 612                                                      wsi->user_space, NULL, 0);
 613 #ifndef LWS_NO_EXTENSIONS
 614         /*
 615          * inform all extensions, not just active ones since they
 616          * already know
 617          */
 618
 619         ext = context->extensions;
 620
 621         while (ext && ext->callback) {
 622                 v = NULL;
 623                 for (n = 0; n < wsi->count_active_extensions; n++)
 624                         if (wsi->active_extensions[n] == ext)
 625                                 v = wsi->active_extensions_user[n];
 626
 627                 ext->callback(context, ext, wsi,
 628                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 629                 ext++;
 630         }
 631 #endif
 632
 633         return 0;
 634
 635 bail3:
 636         if (wsi->c_protocol)
 637                 free(wsi->c_protocol);
 638
 639 bail2:
 640         if (wsi->c_callback) wsi->c_callback(context, wsi,
 641        LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 642                          wsi->user_space,
 643                          NULL, 0);
 644         lwsl_info("closing connection due to bail2 connection error\n");
 645         libwebsocket_close_and_free_session(context, wsi,
 646                                                  LWS_CLOSE_STATUS_PROTOCOL_ERR);
 647
 648         return 1;
 649 }
 650
 651
 652 char *
 653 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 654                 struct libwebsocket *wsi, char *pkt)
 655 {
 656         char hash[20];
 657         char key_b64[40];
 658         char *p = pkt;
 659         int n;
 660 #ifndef LWS_NO_EXTENSIONS
 661         struct libwebsocket_extension *ext;
 662         struct libwebsocket_extension *ext1;
 663         int ext_count = 0;
 664 #endif
 665         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 666                          MAX_USER_RX_BUFFER + LWS_SEND_BUFFER_POST_PADDING];
 667         static const char magic_websocket_guid[] =
 668                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 669
 670         /*
 671          * create the random key
 672          */
 673
 674         n = libwebsockets_get_random(context, hash, 16);
 675         if (n != 16) {
 676                 lwsl_err("Unable to read from random dev %s\n",
 677                                                 SYSTEM_RANDOM_FILEPATH);
 678                 free(wsi->c_path);
 679                 free(wsi->c_host);
 680                 if (wsi->c_origin)
 681                         free(wsi->c_origin);
 682                 if (wsi->c_protocol)
 683                         free(wsi->c_protocol);
 684                 libwebsocket_close_and_free_session(context, wsi,
 685                                              LWS_CLOSE_STATUS_NOSTATUS);
 686                 return NULL;
 687         }
 688
 689         lws_b64_encode_string(hash, 16, key_b64, sizeof key_b64);
 690
 691         /*
 692          * 00 example client handshake
 693          *
 694          * GET /socket.io/websocket HTTP/1.1
 695          * Upgrade: WebSocket
 696          * Connection: Upgrade
 697          * Host: 127.0.0.1:9999
 698          * Origin: http://127.0.0.1
 699          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 700          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 701          * Cookie: socketio=websocket
 702          *
 703          * (Á®Ä0¶†≥
 704          *
 705          * 04 example client handshake
 706          *
 707          * GET /chat HTTP/1.1
 708          * Host: server.example.com
 709          * Upgrade: websocket
 710          * Connection: Upgrade
 711          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 712          * Sec-WebSocket-Origin: http://example.com
 713          * Sec-WebSocket-Protocol: chat, superchat
 714          * Sec-WebSocket-Version: 4
 715          */
 716
 717         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
 718
 719         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 720                                         "Cache-Control: no-cache\x0d\x0a");
 721
 722         p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
 723         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 724                                         "Connection: Upgrade\x0d\x0a"
 725                                         "Sec-WebSocket-Key: ");
 726         strcpy(p, key_b64);
 727         p += strlen(key_b64);
 728         p += sprintf(p, "\x0d\x0a");
 729         if (wsi->c_origin) {
 730                 if (wsi->ietf_spec_revision == 13)
 731                         p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
 732                 else
 733                         p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
 734                                                          wsi->c_origin);
 735         }
 736         if (wsi->c_protocol)
 737                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 738                                                        wsi->c_protocol);
 739
 740         /* tell the server what extensions we could support */
 741
 742         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 743 #ifndef LWS_NO_EXTENSIONS
 744         ext = context->extensions;
 745         while (ext && ext->callback) {
 746
 747                 n = 0;
 748                 ext1 = context->extensions;
 749
 750                 while (ext1 && ext1->callback) {
 751                         n |= ext1->callback(context, ext1, wsi,
 752                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 753                                         NULL, (char *)ext->name, 0);
 754
 755                         ext1++;
 756                 }
 757
 758                 if (n) { /* an extension vetos us */
 759                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 760                         ext++;
 761                         continue;
 762                 }
 763
 764                 n = context->protocols[0].callback(context, wsi,
 765                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 766                                 wsi->user_space, (char *)ext->name, 0);
 767
 768                 /*
 769                  * zero return from callback means
 770                  * go ahead and allow the extension,
 771                  * it's what we get if the callback is
 772                  * unhandled
 773                  */
 774
 775                 if (n) {
 776                         ext++;
 777                         continue;
 778                 }
 779
 780                 /* apply it */
 781
 782                 if (ext_count)
 783                         *p++ = ',';
 784                 p += sprintf(p, "%s", ext->name);
 785                 ext_count++;
 786
 787                 ext++;
 788         }
 789 #endif
 790         p += sprintf(p, "\x0d\x0a");
 791
 792         if (wsi->ietf_spec_revision)
 793                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 794                                                wsi->ietf_spec_revision);
 795
 796         /* give userland a chance to append, eg, cookies */
 797
 798         context->protocols[0].callback(context, wsi,
 799                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 800                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 801
 802         p += sprintf(p, "\x0d\x0a");
 803
 804         /* prepare the expected server accept response */
 805
 806         strcpy((char *)buf, key_b64);
 807         strcpy((char *)&buf[strlen((char *)buf)], magic_websocket_guid);
 808
 809         SHA1(buf, strlen((char *)buf), (unsigned char *)hash);
 810
 811         lws_b64_encode_string(hash, 20,
 812                         wsi->u.hdr.initial_handshake_hash_base64,
 813                              sizeof wsi->u.hdr.initial_handshake_hash_base64);
 814
 815         /* done with these now */
 816
 817         free(wsi->c_path);
 818         free(wsi->c_host);
 819         if (wsi->c_origin)
 820                 free(wsi->c_origin);
 821
 822         return p;
 823 }
 824