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 *p = (char *)&context->service_buffer[0];
  46         int len;
  47         char c;
  48
  49         switch (wsi->mode) {
  50
  51         case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
  52
  53                 /* handle proxy hung up on us */
  54
  55                 if (pollfd->revents & (POLLERR | POLLHUP)) {
  56
  57                         lwsl_warn("Proxy connection %p (fd=%d) dead\n",
  58                                 (void *)wsi, pollfd->fd);
  59
  60                         libwebsocket_close_and_free_session(context, wsi,
  61                                                      LWS_CLOSE_STATUS_NOSTATUS);
  62                         return 0;
  63                 }
  64
  65                 n = recv(wsi->sock, context->service_buffer,
  66                                         sizeof context->service_buffer, 0);
  67                 if (n < 0) {
  68                         libwebsocket_close_and_free_session(context, wsi,
  69                                                      LWS_CLOSE_STATUS_NOSTATUS);
  70                         lwsl_err("ERROR reading from proxy socket\n");
  71                         return 0;
  72                 }
  73
  74                 context->service_buffer[13] = '\0';
  75                 if (strcmp((char *)context->service_buffer, "HTTP/1.0 200 ")) {
  76                         libwebsocket_close_and_free_session(context, wsi,
  77                                                      LWS_CLOSE_STATUS_NOSTATUS);
  78                         lwsl_err("ERROR from proxy: %s\n", context->service_buffer);
  79                         return 0;
  80                 }
  81
  82                 /* clear his proxy connection timeout */
  83
  84                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
  85
  86                 /* fallthru */
  87
  88         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
  89
  90                 /*
  91                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
  92                  * timeout protection set in client-handshake.c
  93                  */
  94
  95         #ifdef LWS_OPENSSL_SUPPORT
  96
  97                 /*
  98                  * take care of our libwebsocket_callback_on_writable
  99                  * happening at a time when there's no real connection yet
 100                  */
 101
 102                 pollfd->events &= ~POLLOUT;
 103
 104                 /* external POLL support via protocol 0 */
 105                 context->protocols[0].callback(context, wsi,
 106                         LWS_CALLBACK_CLEAR_MODE_POLL_FD,
 107                         (void *)(long)wsi->sock, NULL, POLLOUT);
 108
 109                 /* we can retry this... so just cook the SSL BIO the first time */
 110
 111                 if (wsi->use_ssl && !wsi->ssl) {
 112
 113                         wsi->ssl = SSL_new(context->ssl_client_ctx);
 114
 115                         #ifdef USE_CYASSL
 116                         /* CyaSSL does certificate verification differently from OpenSSL.
 117                          * If we should ignore the certificate, we need to set this before
 118                          * SSL_new and SSL_connect is called. Otherwise the connect will
 119                          * simply fail with error code -155 */
 120                         if (wsi->use_ssl == 2) {
 121                                 CyaSSL_set_verify(wsi->ssl, SSL_VERIFY_NONE, NULL);
 122                         }
 123                         #endif // USE_CYASSL
 124
 125                         wsi->client_bio = BIO_new_socket(wsi->sock, BIO_NOCLOSE);
 126
 127                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 128
 129                         #ifdef USE_CYASSL
 130                         CyaSSL_set_using_nonblock(wsi->ssl, 1);
 131                         #else
 132                         BIO_set_nbio(wsi->client_bio, 1); /* nonblocking */
 133                         #endif
 134
 135                         SSL_set_ex_data(wsi->ssl,
 136                                         openssl_websocket_private_data_index,
 137                                                                        context);
 138                 }
 139
 140                 if (wsi->use_ssl) {
 141                         lws_latency_pre(context, wsi);
 142                         n = SSL_connect(wsi->ssl);
 143                         lws_latency(context, wsi, "SSL_connect LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n > 0);
 144
 145                         if (n < 0) {
 146                                 n = SSL_get_error(wsi->ssl, n);
 147
 148                                 if (n == SSL_ERROR_WANT_READ ||
 149                                         n == SSL_ERROR_WANT_WRITE) {
 150                                         /*
 151                                          * wants us to retry connect due to state of the
 152                                          * underlying ssl layer... but since it may be
 153                                          * stalled on blocked write, no incoming data may
 154                                          * arrive to trigger the retry.  Force (possibly
 155                                          * many if the SSL state persists in returning the
 156                                          * condition code, but other sockets are getting
 157                                          * serviced inbetweentimes) us to get called back
 158                                          * when writable.
 159                                          */
 160
 161                                         lwsl_info("SSL_connect -> SSL_ERROR_WANT_... retrying\n");
 162                                         libwebsocket_callback_on_writable(context, wsi);
 163
 164                                         return 0; /* no error */
 165                                 }
 166                                 n = -1;
 167                         }
 168
 169                         if (n <= 0) {
 170                                 /*
 171                                  * retry if new data comes until we
 172                                  * run into the connection timeout or win
 173                                  */
 174
 175                                 lwsl_err("SSL connect error %s\n",
 176                                         ERR_error_string(ERR_get_error(),
 177                                                 (char *)context->service_buffer));
 178                                 return 0;
 179                         }
 180
 181                         #ifndef USE_CYASSL
 182                         /* See note above about CyaSSL certificate verification */
 183                         lws_latency_pre(context, wsi);
 184                         n = SSL_get_verify_result(wsi->ssl);
 185                         lws_latency(context, wsi, "SSL_get_verify_result LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n > 0);
 186                         if ((n != X509_V_OK) && (
 187                                 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 188                                                            wsi->use_ssl != 2)) {
 189
 190                                 lwsl_err("server's cert didn't "
 191                                                            "look good %d\n", n);
 192                                 libwebsocket_close_and_free_session(context,
 193                                                 wsi, LWS_CLOSE_STATUS_NOSTATUS);
 194                                 return 0;
 195                         }
 196                         #endif // USE_CYASSL
 197                 } else
 198                         wsi->ssl = NULL;
 199         #endif
 200
 201                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 202                 if (p == NULL) {
 203                         lwsl_err("Failed to generate handshake for client, closing it\n");
 204                         libwebsocket_close_and_free_session(context, wsi,
 205                                                      LWS_CLOSE_STATUS_NOSTATUS);
 206                         return 0;
 207                 }
 208
 209                 /* send our request to the server */
 210
 211                 lws_latency_pre(context, wsi);
 212         #ifdef LWS_OPENSSL_SUPPORT
 213                 if (wsi->use_ssl)
 214                         n = SSL_write(wsi->ssl, context->service_buffer, p - (char *)context->service_buffer);
 215                 else
 216         #endif
 217                         n = send(wsi->sock, context->service_buffer, p - (char *)context->service_buffer, 0);
 218                 lws_latency(context, wsi, "send or SSL_write LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n >= 0);
 219
 220                 if (n < 0) {
 221                         lwsl_debug("ERROR writing to client socket\n");
 222                         libwebsocket_close_and_free_session(context, wsi,
 223                                                      LWS_CLOSE_STATUS_NOSTATUS);
 224                         return 0;
 225                 }
 226
 227                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 228                 wsi->u.hdr.lextable_pos = 0;
 229                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 230                 libwebsocket_set_timeout(wsi,
 231                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE, AWAITING_TIMEOUT);
 232
 233                 break;
 234
 235         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 236
 237                 /* handle server hung up on us */
 238
 239                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 240
 241                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 242                                 (void *)wsi, pollfd->fd);
 243
 244                         goto bail3;
 245                 }
 246
 247                 if (!(pollfd->revents & POLLIN))
 248                         goto bail3;
 249
 250                 /* interpret the server response */
 251
 252                 /*
 253                  *  HTTP/1.1 101 Switching Protocols
 254                  *  Upgrade: websocket
 255                  *  Connection: Upgrade
 256                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 257                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 258                  *  Sec-WebSocket-Protocol: chat
 259                  */
 260
 261                 /*
 262                  * we have to take some care here to only take from the
 263                  * socket bytewise.  The browser may (and has been seen to
 264                  * in the case that onopen() performs websocket traffic)
 265                  * coalesce both handshake response and websocket traffic
 266                  * in one packet, since at that point the connection is
 267                  * definitively ready from browser pov.
 268                  */
 269
 270                 len = 1;
 271                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE && len > 0) {
 272 #ifdef LWS_OPENSSL_SUPPORT
 273                         if (wsi->use_ssl) {
 274                                 len = SSL_read(wsi->ssl, &c, 1);
 275                                 if (len < 0) {
 276                                         n = SSL_get_error(wsi->ssl, len);
 277                                         if (n ==  SSL_ERROR_WANT_READ ||
 278                                                         n ==  SSL_ERROR_WANT_WRITE)
 279                                                 return 0;
 280                                 }
 281                         } else
 282 #endif
 283                                 len = recv(wsi->sock, &c, 1, 0);
 284
 285                         if (len < 0)
 286                                 goto bail3;
 287
 288                         if (libwebsocket_parse(wsi, c)) {
 289                                 /* problems */
 290                                 goto bail3;
 291                         }
 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         char *p;
 354         int len;
 355 #ifndef LWS_NO_EXTENSIONS
 356         char ext_name[128];
 357         struct libwebsocket_extension *ext;
 358         void *v;
 359         int more = 1;
 360         const char *c;
 361 #endif
 362         int n;
 363
 364         /*
 365          * well, what the server sent looked reasonable for syntax.
 366          * Now let's confirm it sent all the necessary headers
 367          */
 368
 369         if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0)
 370                 goto bail3;
 371
 372         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 373         if (!p)
 374                 goto bail3;
 375         if (p && strncmp(p, "101", 3)) {
 376                 lwsl_warn("libwebsocket_client_handshake "
 377                                 "server sent bad HTTP response '%s'\n", p);
 378                 goto bail3;
 379         }
 380
 381         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
 382         if (!p)
 383                 goto bail3;
 384         strtolower(p);
 385         if (strcmp(p, "websocket")) {
 386                 lwsl_warn("libwebsocket_client_handshake server "
 387                                 "sent bad Upgrade header '%s'\n", p);
 388                 goto bail3;
 389         }
 390
 391         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
 392         if (!p)
 393                 goto bail3;
 394         strtolower(p);
 395         if (strcmp(p, "upgrade")) {
 396                 lwsl_warn("libwebsocket_client_handshake server "
 397                                 "sent bad Connection hdr '%s'\n", p);
 398                 goto bail3;
 399         }
 400
 401         pc = wsi->c_protocol;
 402         if (pc == NULL)
 403                 lwsl_parser("lws_client_interpret_server_handshake: "
 404                                                           "NULL c_protocol\n");
 405         else
 406                 lwsl_parser("lws_client_interpret_server_handshake: "
 407                                                       "cPprotocol='%s'\n", pc);
 408
 409         /*
 410          * confirm the protocol the server wants to talk was in the list
 411          * of protocols we offered
 412          */
 413
 414         len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
 415         if (!len) {
 416
 417                 lwsl_info("lws_client_interpret_server_handshake "
 418                                                "WSI_TOKEN_PROTOCOL is null\n");
 419                 /*
 420                  * no protocol name to work from,
 421                  * default to first protocol
 422                  */
 423                 wsi->protocol = &context->protocols[0];
 424                 wsi->c_callback = wsi->protocol->callback;
 425                 free(wsi->c_protocol);
 426
 427                 goto check_extensions;
 428         }
 429
 430         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
 431         len = strlen(p);
 432
 433         while (*pc && !okay) {
 434                 if (!strncmp(pc, p, len) && (pc[len] == ',' || pc[len] == '\0')) {
 435                         okay = 1;
 436                         continue;
 437                 }
 438                 while (*pc && *pc != ',')
 439                         pc++;
 440                 while (*pc && *pc != ' ')
 441                         pc++;
 442         }
 443
 444         /* done with him now */
 445
 446         if (wsi->c_protocol)
 447                 free(wsi->c_protocol);
 448
 449         if (!okay) {
 450                 lwsl_err("libwebsocket_client_handshake server "
 451                                         "sent bad protocol '%s'\n", p);
 452                 goto bail2;
 453         }
 454
 455         /*
 456          * identify the selected protocol struct and set it
 457          */
 458         n = 0;
 459         wsi->protocol = NULL;
 460         while (context->protocols[n].callback && !wsi->protocol) {
 461                 if (strcmp(p, context->protocols[n].name) == 0) {
 462                         wsi->protocol = &context->protocols[n];
 463                         wsi->c_callback = wsi->protocol->callback;
 464                         break;
 465                 }
 466                 n++;
 467         }
 468
 469         if (wsi->protocol == NULL) {
 470                 lwsl_err("libwebsocket_client_handshake server "
 471                                 "requested protocol '%s', which we "
 472                                 "said we supported but we don't!\n", p);
 473                 goto bail2;
 474         }
 475
 476
 477 check_extensions:
 478 #ifndef LWS_NO_EXTENSIONS
 479         /* instantiate the accepted extensions */
 480
 481         if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
 482                 lwsl_ext("no client extenstions allowed by server\n");
 483                 goto check_accept;
 484         }
 485
 486         /*
 487          * break down the list of server accepted extensions
 488          * and go through matching them or identifying bogons
 489          */
 490
 491         if (lws_hdr_copy(wsi, (char *)context->service_buffer, sizeof(context->service_buffer), WSI_TOKEN_EXTENSIONS) < 0)
 492                 goto bail2;
 493
 494         c = (char *)context->service_buffer;
 495         n = 0;
 496         while (more) {
 497
 498                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 499                         ext_name[n] = *c++;
 500                         if (n < sizeof(ext_name) - 1)
 501                                 n++;
 502                         continue;
 503                 }
 504                 ext_name[n] = '\0';
 505                 if (!*c)
 506                         more = 0;
 507                 else {
 508                         c++;
 509                         if (!n)
 510                                 continue;
 511                 }
 512
 513                 /* check we actually support it */
 514
 515                 lwsl_ext("checking client ext %s\n", ext_name);
 516
 517                 n = 0;
 518                 ext = wsi->protocol->owning_server->extensions;
 519                 while (ext && ext->callback) {
 520
 521                         if (strcmp(ext_name, ext->name)) {
 522                                 ext++;
 523                                 continue;
 524                         }
 525
 526                         n = 1;
 527
 528                         lwsl_ext("instantiating client ext %s\n", ext_name);
 529
 530                         /* instantiate the extension on this conn */
 531
 532                         wsi->active_extensions_user[
 533                                 wsi->count_active_extensions] =
 534                                          malloc(ext->per_session_data_size);
 535                         if (wsi->active_extensions_user[
 536                                 wsi->count_active_extensions] == NULL) {
 537                                 lwsl_err("Out of mem\n");
 538                                 goto bail2;
 539                         }
 540                         memset(wsi->active_extensions_user[
 541                                 wsi->count_active_extensions], 0,
 542                                                     ext->per_session_data_size);
 543                         wsi->active_extensions[
 544                                   wsi->count_active_extensions] = ext;
 545
 546                         /* allow him to construct his context */
 547
 548                         ext->callback(wsi->protocol->owning_server,
 549                                 ext, wsi,
 550                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 551                                         wsi->active_extensions_user[
 552                                          wsi->count_active_extensions],
 553                                                                    NULL, 0);
 554
 555                         wsi->count_active_extensions++;
 556
 557                         ext++;
 558                 }
 559
 560                 if (n == 0) {
 561                         lwsl_warn("Server said we should use"
 562                                   "an unknown extension '%s'!\n", ext_name);
 563                         goto bail2;
 564                 }
 565
 566                 n = 0;
 567         }
 568
 569 check_accept:
 570 #endif
 571
 572         /*
 573          * Confirm his accept token is the one we precomputed
 574          */
 575
 576         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
 577         if (strcmp(p, wsi->u.hdr.initial_handshake_hash_base64)) {
 578                 lwsl_warn("libwebsocket_client_handshake server "
 579                         "sent bad ACCEPT '%s' vs computed '%s'\n", p,
 580                                       wsi->u.hdr.initial_handshake_hash_base64);
 581                 goto bail2;
 582         }
 583
 584         /* allocate the per-connection user memory (if any) */
 585         if (wsi->protocol->per_session_data_size &&
 586                                           !libwebsocket_ensure_user_space(wsi))
 587                 goto bail2;
 588
 589         /*
 590          * we seem to be good to go, give client last chance to check
 591          * headers and OK it
 592          */
 593
 594         wsi->protocol->callback(context, wsi,
 595                                 LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
 596                                                      wsi->user_space, NULL, 0);
 597
 598         /* clear his proxy connection timeout */
 599
 600         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 601
 602         /* free up his parsing allocations */
 603         if (wsi->u.hdr.ah)
 604                 free(wsi->u.hdr.ah);
 605
 606         /* mark him as being alive */
 607
 608         wsi->state = WSI_STATE_ESTABLISHED;
 609         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 610
 611         /* union transition */
 612
 613         memset(&wsi->u, 0, sizeof wsi->u);
 614
 615         /*
 616          * create the frame buffer for this connection according to the
 617          * size mentioned in the protocol definition.  If 0 there, then
 618          * use a big default for compatibility
 619          */
 620
 621         n = wsi->protocol->rx_buffer_size;
 622         if (!n)
 623                 n = LWS_MAX_SOCKET_IO_BUF;
 624         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 625         wsi->u.ws.rx_user_buffer = malloc(n);
 626         if (!wsi->u.ws.rx_user_buffer) {
 627                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 628                 goto bail3;
 629         }
 630         lwsl_info("Allocating client RX buffer %d\n", n);
 631
 632         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 633
 634         /* call him back to inform him he is up */
 635
 636         wsi->protocol->callback(context, wsi,
 637                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 638                                                      wsi->user_space, NULL, 0);
 639 #ifndef LWS_NO_EXTENSIONS
 640         /*
 641          * inform all extensions, not just active ones since they
 642          * already know
 643          */
 644
 645         ext = context->extensions;
 646
 647         while (ext && ext->callback) {
 648                 v = NULL;
 649                 for (n = 0; n < wsi->count_active_extensions; n++)
 650                         if (wsi->active_extensions[n] == ext)
 651                                 v = wsi->active_extensions_user[n];
 652
 653                 ext->callback(context, ext, wsi,
 654                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 655                 ext++;
 656         }
 657 #endif
 658
 659         return 0;
 660
 661 bail3:
 662         if (wsi->c_protocol)
 663                 free(wsi->c_protocol);
 664
 665 bail2:
 666         if (wsi->c_callback)
 667                 wsi->c_callback(context, wsi,
 668                         LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 669                                                       wsi->user_space, NULL, 0);
 670
 671         lwsl_info("closing connection due to bail2 connection error\n");
 672
 673         /* free up his parsing allocations */
 674
 675         if (wsi->u.hdr.ah)
 676                 free(wsi->u.hdr.ah);
 677
 678         libwebsocket_close_and_free_session(context, wsi,
 679                                                  LWS_CLOSE_STATUS_PROTOCOL_ERR);
 680
 681         return 1;
 682 }
 683
 684
 685 char *
 686 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 687                 struct libwebsocket *wsi, char *pkt)
 688 {
 689         char buf[128];
 690         char hash[20];
 691         char key_b64[40];
 692         char *p = pkt;
 693         int n;
 694 #ifndef LWS_NO_EXTENSIONS
 695         struct libwebsocket_extension *ext;
 696         struct libwebsocket_extension *ext1;
 697         int ext_count = 0;
 698 #endif
 699         static const char magic_websocket_guid[] =
 700                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 701
 702         /*
 703          * create the random key
 704          */
 705
 706         n = libwebsockets_get_random(context, hash, 16);
 707         if (n != 16) {
 708                 lwsl_err("Unable to read from random dev %s\n",
 709                                                 SYSTEM_RANDOM_FILEPATH);
 710                 free(wsi->c_path);
 711                 free(wsi->c_host);
 712                 if (wsi->c_origin)
 713                         free(wsi->c_origin);
 714                 if (wsi->c_protocol)
 715                         free(wsi->c_protocol);
 716                 libwebsocket_close_and_free_session(context, wsi,
 717                                              LWS_CLOSE_STATUS_NOSTATUS);
 718                 return NULL;
 719         }
 720
 721         lws_b64_encode_string(hash, 16, key_b64, sizeof key_b64);
 722
 723         /*
 724          * 00 example client handshake
 725          *
 726          * GET /socket.io/websocket HTTP/1.1
 727          * Upgrade: WebSocket
 728          * Connection: Upgrade
 729          * Host: 127.0.0.1:9999
 730          * Origin: http://127.0.0.1
 731          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 732          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 733          * Cookie: socketio=websocket
 734          *
 735          * (Á®Ä0¶†≥
 736          *
 737          * 04 example client handshake
 738          *
 739          * GET /chat HTTP/1.1
 740          * Host: server.example.com
 741          * Upgrade: websocket
 742          * Connection: Upgrade
 743          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 744          * Sec-WebSocket-Origin: http://example.com
 745          * Sec-WebSocket-Protocol: chat, superchat
 746          * Sec-WebSocket-Version: 4
 747          */
 748
 749         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
 750
 751         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 752                                         "Cache-Control: no-cache\x0d\x0a");
 753
 754         p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
 755         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 756                                         "Connection: Upgrade\x0d\x0a"
 757                                         "Sec-WebSocket-Key: ");
 758         strcpy(p, key_b64);
 759         p += strlen(key_b64);
 760         p += sprintf(p, "\x0d\x0a");
 761         if (wsi->c_origin) {
 762                 if (wsi->ietf_spec_revision == 13)
 763                         p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
 764                 else
 765                         p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
 766                                                          wsi->c_origin);
 767         }
 768         if (wsi->c_protocol)
 769                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 770                                                        wsi->c_protocol);
 771
 772         /* tell the server what extensions we could support */
 773
 774         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 775 #ifndef LWS_NO_EXTENSIONS
 776         ext = context->extensions;
 777         while (ext && ext->callback) {
 778
 779                 n = 0;
 780                 ext1 = context->extensions;
 781
 782                 while (ext1 && ext1->callback) {
 783                         n |= ext1->callback(context, ext1, wsi,
 784                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 785                                         NULL, (char *)ext->name, 0);
 786
 787                         ext1++;
 788                 }
 789
 790                 if (n) { /* an extension vetos us */
 791                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 792                         ext++;
 793                         continue;
 794                 }
 795
 796                 n = context->protocols[0].callback(context, wsi,
 797                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 798                                 wsi->user_space, (char *)ext->name, 0);
 799
 800                 /*
 801                  * zero return from callback means
 802                  * go ahead and allow the extension,
 803                  * it's what we get if the callback is
 804                  * unhandled
 805                  */
 806
 807                 if (n) {
 808                         ext++;
 809                         continue;
 810                 }
 811
 812                 /* apply it */
 813
 814                 if (ext_count)
 815                         *p++ = ',';
 816                 p += sprintf(p, "%s", ext->name);
 817                 ext_count++;
 818
 819                 ext++;
 820         }
 821 #endif
 822         p += sprintf(p, "\x0d\x0a");
 823
 824         if (wsi->ietf_spec_revision)
 825                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 826                                                wsi->ietf_spec_revision);
 827
 828         /* give userland a chance to append, eg, cookies */
 829
 830         context->protocols[0].callback(context, wsi,
 831                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 832                 NULL, &p, (pkt + sizeof(context->service_buffer)) - p - 12);
 833
 834         p += sprintf(p, "\x0d\x0a");
 835
 836         /* prepare the expected server accept response */
 837
 838         n = snprintf(buf, sizeof buf, "%s%s", key_b64, magic_websocket_guid);
 839         buf[sizeof(buf) - 1] = '\0';
 840         SHA1((unsigned char *)buf, n, (unsigned char *)hash);
 841
 842         lws_b64_encode_string(hash, 20,
 843                         wsi->u.hdr.initial_handshake_hash_base64,
 844                              sizeof wsi->u.hdr.initial_handshake_hash_base64);
 845
 846         /* done with these now */
 847
 848         free(wsi->c_path);
 849         free(wsi->c_host);
 850         if (wsi->c_origin)
 851                 free(wsi->c_origin);
 852
 853         return p;
 854 }
 855