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                 lwsl_info("closing connection at LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY\n");
 313                 libwebsocket_close_and_free_session(context, wsi,
 314                                                     LWS_CLOSE_STATUS_NOSTATUS);
 315                 return 0;
 316
 317         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 318                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 319                 break;
 320
 321         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 322                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 323                 break;
 324         default:
 325                 break;
 326         }
 327
 328         return 0;
 329 }
 330
 331
 332 /*
 333  * In-place str to lower case
 334  */
 335
 336 static void
 337 strtolower(char *s)
 338 {
 339         while (*s) {
 340                 *s = tolower(*s);
 341                 s++;
 342         }
 343 }
 344
 345 int
 346 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 347                 struct libwebsocket *wsi)
 348 {
 349         const char *pc;
 350         int okay = 0;
 351         char *p;
 352         int len;
 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
 367         if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0)
 368                 goto bail3;
 369
 370         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 371         if (!p)
 372                 goto bail3;
 373         if (p && strncmp(p, "101", 3)) {
 374                 lwsl_warn("libwebsocket_client_handshake "
 375                                 "server sent bad HTTP response '%s'\n", p);
 376                 goto bail3;
 377         }
 378
 379         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
 380         if (!p)
 381                 goto bail3;
 382         strtolower(p);
 383         if (strcmp(p, "websocket")) {
 384                 lwsl_warn("libwebsocket_client_handshake server "
 385                                 "sent bad Upgrade header '%s'\n", p);
 386                 goto bail3;
 387         }
 388
 389         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
 390         if (!p)
 391                 goto bail3;
 392         strtolower(p);
 393         if (strcmp(p, "upgrade")) {
 394                 lwsl_warn("libwebsocket_client_handshake server "
 395                                 "sent bad Connection hdr '%s'\n", p);
 396                 goto bail3;
 397         }
 398
 399         pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);
 400         if (pc == NULL)
 401                 lwsl_parser("lws_client_interpret_server_handshake: "
 402                                                           "NULL c_protocol\n");
 403         else
 404                 lwsl_parser("lws_client_interpret_server_handshake: "
 405                                                       "cPprotocol='%s'\n", pc);
 406
 407         /*
 408          * confirm the protocol the server wants to talk was in the list
 409          * of protocols we offered
 410          */
 411
 412         len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
 413         if (!len) {
 414
 415                 lwsl_info("lws_client_interpret_server_handshake "
 416                                                "WSI_TOKEN_PROTOCOL is null\n");
 417                 /*
 418                  * no protocol name to work from,
 419                  * default to first protocol
 420                  */
 421                 wsi->protocol = &context->protocols[0];
 422                 goto check_extensions;
 423         }
 424
 425         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
 426         len = strlen(p);
 427
 428         while (*pc && !okay) {
 429                 if (!strncmp(pc, p, len) && (pc[len] == ',' || pc[len] == '\0')) {
 430                         okay = 1;
 431                         continue;
 432                 }
 433                 while (*pc && *pc != ',')
 434                         pc++;
 435                 while (*pc && *pc != ' ')
 436                         pc++;
 437         }
 438
 439         if (!okay) {
 440                 lwsl_err("libwebsocket_client_handshake server "
 441                                         "sent bad protocol '%s'\n", p);
 442                 goto bail2;
 443         }
 444
 445         /*
 446          * identify the selected protocol struct and set it
 447          */
 448         n = 0;
 449         wsi->protocol = NULL;
 450         while (context->protocols[n].callback && !wsi->protocol) {
 451                 if (strcmp(p, context->protocols[n].name) == 0) {
 452                         wsi->protocol = &context->protocols[n];
 453                         break;
 454                 }
 455                 n++;
 456         }
 457
 458         if (wsi->protocol == NULL) {
 459                 lwsl_err("libwebsocket_client_handshake server "
 460                                 "requested protocol '%s', which we "
 461                                 "said we supported but we don't!\n", p);
 462                 goto bail2;
 463         }
 464
 465
 466 check_extensions:
 467 #ifndef LWS_NO_EXTENSIONS
 468         /* instantiate the accepted extensions */
 469
 470         if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
 471                 lwsl_ext("no client extenstions allowed by server\n");
 472                 goto check_accept;
 473         }
 474
 475         /*
 476          * break down the list of server accepted extensions
 477          * and go through matching them or identifying bogons
 478          */
 479
 480         if (lws_hdr_copy(wsi, (char *)context->service_buffer, sizeof(context->service_buffer), WSI_TOKEN_EXTENSIONS) < 0)
 481                 goto bail2;
 482
 483         c = (char *)context->service_buffer;
 484         n = 0;
 485         while (more) {
 486
 487                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 488                         ext_name[n] = *c++;
 489                         if (n < sizeof(ext_name) - 1)
 490                                 n++;
 491                         continue;
 492                 }
 493                 ext_name[n] = '\0';
 494                 if (!*c)
 495                         more = 0;
 496                 else {
 497                         c++;
 498                         if (!n)
 499                                 continue;
 500                 }
 501
 502                 /* check we actually support it */
 503
 504                 lwsl_ext("checking client ext %s\n", ext_name);
 505
 506                 n = 0;
 507                 ext = wsi->protocol->owning_server->extensions;
 508                 while (ext && ext->callback) {
 509
 510                         if (strcmp(ext_name, ext->name)) {
 511                                 ext++;
 512                                 continue;
 513                         }
 514
 515                         n = 1;
 516
 517                         lwsl_ext("instantiating client ext %s\n", ext_name);
 518
 519                         /* instantiate the extension on this conn */
 520
 521                         wsi->active_extensions_user[
 522                                 wsi->count_active_extensions] =
 523                                          malloc(ext->per_session_data_size);
 524                         if (wsi->active_extensions_user[
 525                                 wsi->count_active_extensions] == NULL) {
 526                                 lwsl_err("Out of mem\n");
 527                                 goto bail2;
 528                         }
 529                         memset(wsi->active_extensions_user[
 530                                 wsi->count_active_extensions], 0,
 531                                                     ext->per_session_data_size);
 532                         wsi->active_extensions[
 533                                   wsi->count_active_extensions] = ext;
 534
 535                         /* allow him to construct his context */
 536
 537                         ext->callback(wsi->protocol->owning_server,
 538                                 ext, wsi,
 539                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 540                                         wsi->active_extensions_user[
 541                                          wsi->count_active_extensions],
 542                                                                    NULL, 0);
 543
 544                         wsi->count_active_extensions++;
 545
 546                         ext++;
 547                 }
 548
 549                 if (n == 0) {
 550                         lwsl_warn("Server said we should use"
 551                                   "an unknown extension '%s'!\n", ext_name);
 552                         goto bail2;
 553                 }
 554
 555                 n = 0;
 556         }
 557
 558 check_accept:
 559 #endif
 560
 561         /*
 562          * Confirm his accept token is the one we precomputed
 563          */
 564
 565         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
 566         if (strcmp(p, wsi->u.hdr.initial_handshake_hash_base64)) {
 567                 lwsl_warn("libwebsocket_client_handshake server "
 568                         "sent bad ACCEPT '%s' vs computed '%s'\n", p,
 569                                       wsi->u.hdr.initial_handshake_hash_base64);
 570                 goto bail2;
 571         }
 572
 573         /* allocate the per-connection user memory (if any) */
 574         if (wsi->protocol->per_session_data_size &&
 575                                           !libwebsocket_ensure_user_space(wsi))
 576                 goto bail2;
 577
 578         /*
 579          * we seem to be good to go, give client last chance to check
 580          * headers and OK it
 581          */
 582
 583         wsi->protocol->callback(context, wsi,
 584                                 LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
 585                                                      wsi->user_space, NULL, 0);
 586
 587         /* clear his proxy connection timeout */
 588
 589         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 590
 591         /* free up his parsing allocations */
 592         if (wsi->u.hdr.ah)
 593                 free(wsi->u.hdr.ah);
 594
 595         /* mark him as being alive */
 596
 597         wsi->state = WSI_STATE_ESTABLISHED;
 598         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 599
 600         /* union transition */
 601
 602         memset(&wsi->u, 0, sizeof wsi->u);
 603
 604         /*
 605          * create the frame buffer for this connection according to the
 606          * size mentioned in the protocol definition.  If 0 there, then
 607          * use a big default for compatibility
 608          */
 609
 610         n = wsi->protocol->rx_buffer_size;
 611         if (!n)
 612                 n = LWS_MAX_SOCKET_IO_BUF;
 613         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 614         wsi->u.ws.rx_user_buffer = malloc(n);
 615         if (!wsi->u.ws.rx_user_buffer) {
 616                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 617                 goto bail3;
 618         }
 619         lwsl_info("Allocating client RX buffer %d\n", n);
 620
 621         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 622
 623         /* call him back to inform him he is up */
 624
 625         wsi->protocol->callback(context, wsi,
 626                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 627                                                      wsi->user_space, NULL, 0);
 628 #ifndef LWS_NO_EXTENSIONS
 629         /*
 630          * inform all extensions, not just active ones since they
 631          * already know
 632          */
 633
 634         ext = context->extensions;
 635
 636         while (ext && ext->callback) {
 637                 v = NULL;
 638                 for (n = 0; n < wsi->count_active_extensions; n++)
 639                         if (wsi->active_extensions[n] == ext)
 640                                 v = wsi->active_extensions_user[n];
 641
 642                 ext->callback(context, ext, wsi,
 643                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 644                 ext++;
 645         }
 646 #endif
 647
 648         return 0;
 649
 650 bail3:
 651
 652 bail2:
 653         if (wsi->protocol)
 654                 wsi->protocol->callback(context, wsi,
 655                         LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 656                                                       wsi->user_space, NULL, 0);
 657
 658         lwsl_info("closing connection due to bail2 connection error\n");
 659
 660         /* free up his parsing allocations */
 661
 662         if (wsi->u.hdr.ah)
 663                 free(wsi->u.hdr.ah);
 664
 665         libwebsocket_close_and_free_session(context, wsi,
 666                                                  LWS_CLOSE_STATUS_PROTOCOL_ERR);
 667
 668         return 1;
 669 }
 670
 671
 672 char *
 673 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 674                 struct libwebsocket *wsi, char *pkt)
 675 {
 676         char buf[128];
 677         char hash[20];
 678         char key_b64[40];
 679         char *p = pkt;
 680         int n;
 681 #ifndef LWS_NO_EXTENSIONS
 682         struct libwebsocket_extension *ext;
 683         struct libwebsocket_extension *ext1;
 684         int ext_count = 0;
 685 #endif
 686         static const char magic_websocket_guid[] =
 687                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 688
 689         /*
 690          * create the random key
 691          */
 692
 693         n = libwebsockets_get_random(context, hash, 16);
 694         if (n != 16) {
 695                 lwsl_err("Unable to read from random dev %s\n",
 696                                                 SYSTEM_RANDOM_FILEPATH);
 697                 libwebsocket_close_and_free_session(context, wsi,
 698                                              LWS_CLOSE_STATUS_NOSTATUS);
 699                 return NULL;
 700         }
 701
 702         lws_b64_encode_string(hash, 16, key_b64, sizeof key_b64);
 703
 704         /*
 705          * 00 example client handshake
 706          *
 707          * GET /socket.io/websocket HTTP/1.1
 708          * Upgrade: WebSocket
 709          * Connection: Upgrade
 710          * Host: 127.0.0.1:9999
 711          * Origin: http://127.0.0.1
 712          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 713          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 714          * Cookie: socketio=websocket
 715          *
 716          * (Á®Ä0¶†≥
 717          *
 718          * 04 example client handshake
 719          *
 720          * GET /chat HTTP/1.1
 721          * Host: server.example.com
 722          * Upgrade: websocket
 723          * Connection: Upgrade
 724          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 725          * Sec-WebSocket-Origin: http://example.com
 726          * Sec-WebSocket-Protocol: chat, superchat
 727          * Sec-WebSocket-Version: 4
 728          */
 729
 730         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_URI));
 731
 732         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 733                                         "Cache-Control: no-cache\x0d\x0a");
 734
 735         p += sprintf(p, "Host: %s\x0d\x0a", lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_HOST));
 736         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 737                                         "Connection: Upgrade\x0d\x0a"
 738                                         "Sec-WebSocket-Key: ");
 739         strcpy(p, key_b64);
 740         p += strlen(key_b64);
 741         p += sprintf(p, "\x0d\x0a");
 742         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN))
 743                 p += sprintf(p, "Origin: %s\x0d\x0a", lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN));
 744
 745         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))
 746                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 747                                 lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));
 748
 749         /* tell the server what extensions we could support */
 750
 751         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 752 #ifndef LWS_NO_EXTENSIONS
 753         ext = context->extensions;
 754         while (ext && ext->callback) {
 755
 756                 n = 0;
 757                 ext1 = context->extensions;
 758
 759                 while (ext1 && ext1->callback) {
 760                         n |= ext1->callback(context, ext1, wsi,
 761                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 762                                         NULL, (char *)ext->name, 0);
 763
 764                         ext1++;
 765                 }
 766
 767                 if (n) { /* an extension vetos us */
 768                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 769                         ext++;
 770                         continue;
 771                 }
 772
 773                 n = context->protocols[0].callback(context, wsi,
 774                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 775                                 wsi->user_space, (char *)ext->name, 0);
 776
 777                 /*
 778                  * zero return from callback means
 779                  * go ahead and allow the extension,
 780                  * it's what we get if the callback is
 781                  * unhandled
 782                  */
 783
 784                 if (n) {
 785                         ext++;
 786                         continue;
 787                 }
 788
 789                 /* apply it */
 790
 791                 if (ext_count)
 792                         *p++ = ',';
 793                 p += sprintf(p, "%s", ext->name);
 794                 ext_count++;
 795
 796                 ext++;
 797         }
 798 #endif
 799         p += sprintf(p, "\x0d\x0a");
 800
 801         if (wsi->ietf_spec_revision)
 802                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 803                                                wsi->ietf_spec_revision);
 804
 805         /* give userland a chance to append, eg, cookies */
 806
 807         context->protocols[0].callback(context, wsi,
 808                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 809                 NULL, &p, (pkt + sizeof(context->service_buffer)) - p - 12);
 810
 811         p += sprintf(p, "\x0d\x0a");
 812
 813         /* prepare the expected server accept response */
 814
 815         n = snprintf(buf, sizeof buf, "%s%s", key_b64, magic_websocket_guid);
 816         buf[sizeof(buf) - 1] = '\0';
 817         SHA1((unsigned char *)buf, n, (unsigned char *)hash);
 818
 819         lws_b64_encode_string(hash, 20,
 820                         wsi->u.hdr.initial_handshake_hash_base64,
 821                              sizeof wsi->u.hdr.initial_handshake_hash_base64);
 822
 823         return p;
 824 }
 825