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                         if (libwebsocket_parse(wsi, c)) {
 292                                 /* problems */
 293                                 goto bail3;
 294                         }
 295                 }
 296
 297                 /*
 298                  * hs may also be coming in multiple packets, there is a 5-sec
 299                  * libwebsocket timeout still active here too, so if parsing did
 300                  * not complete just wait for next packet coming in this state
 301                  */
 302
 303                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 304                         break;
 305
 306                 /*
 307                  * otherwise deal with the handshake.  If there's any
 308                  * packet traffic already arrived we'll trigger poll() again
 309                  * right away and deal with it that way
 310                  */
 311
 312                 return lws_client_interpret_server_handshake(context, wsi);
 313
 314 bail3:
 315                 if (wsi->c_protocol)
 316                         free(wsi->c_protocol);
 317                 lwsl_info("closing connection at LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY\n");
 318                 libwebsocket_close_and_free_session(context, wsi,
 319                                                     LWS_CLOSE_STATUS_NOSTATUS);
 320                 return 0;
 321
 322         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 323                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 324                 break;
 325
 326         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 327                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 328                 break;
 329         default:
 330                 break;
 331         }
 332
 333         return 0;
 334 }
 335
 336
 337 /*
 338  * In-place str to lower case
 339  */
 340
 341 static void
 342 strtolower(char *s)
 343 {
 344         while (*s) {
 345                 *s = tolower(*s);
 346                 s++;
 347         }
 348 }
 349
 350 int
 351 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 352                 struct libwebsocket *wsi)
 353 {
 354         const char *pc;
 355         int okay = 0;
 356 #ifndef LWS_NO_EXTENSIONS
 357         char ext_name[128];
 358         struct libwebsocket_extension *ext;
 359         void *v;
 360         int more = 1;
 361         const char *c;
 362 #endif
 363         int n;
 364
 365         /*
 366          * well, what the server sent looked reasonable for syntax.
 367          * Now let's confirm it sent all the necessary headers
 368          */
 369 #if 0
 370         lwsl_parser("WSI_TOKEN_HTTP: %d\n",
 371                                     wsi->utf8_token[WSI_TOKEN_HTTP].token_len);
 372         lwsl_parser("WSI_TOKEN_UPGRADE: %d\n",
 373                                  wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len);
 374         lwsl_parser("WSI_TOKEN_CONNECTION: %d\n",
 375                               wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len);
 376         lwsl_parser("WSI_TOKEN_ACCEPT: %d\n",
 377                                   wsi->utf8_token[WSI_TOKEN_ACCEPT].token_len);
 378         lwsl_parser("WSI_TOKEN_NONCE: %d\n",
 379                                    wsi->utf8_token[WSI_TOKEN_NONCE].token_len);
 380         lwsl_parser("WSI_TOKEN_PROTOCOL: %d\n",
 381                                 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len);
 382 #endif
 383
 384         strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
 385         if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
 386                 lwsl_warn("libwebsocket_client_handshake "
 387                                 "server sent bad HTTP response '%s'\n",
 388                                  wsi->utf8_token[WSI_TOKEN_HTTP].token);
 389                 goto bail3;
 390         }
 391
 392         strtolower(wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 393         if (strcmp(wsi->utf8_token[WSI_TOKEN_UPGRADE].token,
 394                                                          "websocket")) {
 395                 lwsl_warn("libwebsocket_client_handshake server "
 396                                 "sent bad Upgrade header '%s'\n",
 397                                   wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 398                 goto bail3;
 399         }
 400
 401         strtolower(wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 402         if (strcmp(wsi->utf8_token[WSI_TOKEN_CONNECTION].token,
 403                                                            "upgrade")) {
 404                 lwsl_warn("libwebsocket_client_handshake server "
 405                                 "sent bad Connection hdr '%s'\n",
 406                            wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 407                 goto bail3;
 408         }
 409
 410         pc = wsi->c_protocol;
 411         if (pc == NULL)
 412                 lwsl_parser("lws_client_interpret_server_handshake: "
 413                                                           "NULL c_protocol\n");
 414         else
 415                 lwsl_parser("lws_client_interpret_server_handshake: "
 416                                                       "cPprotocol='%s'\n", pc);
 417
 418         /*
 419          * confirm the protocol the server wants to talk was in the list
 420          * of protocols we offered
 421          */
 422
 423         if (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len) {
 424
 425                 lwsl_info("lws_client_interpret_server_handshake "
 426                                                "WSI_TOKEN_PROTOCOL is null\n");
 427                 /*
 428                  * no protocol name to work from,
 429                  * default to first protocol
 430                  */
 431                 wsi->protocol = &context->protocols[0];
 432                 wsi->c_callback = wsi->protocol->callback;
 433                 free(wsi->c_protocol);
 434
 435                 goto check_extensions;
 436         }
 437
 438         while (*pc && !okay) {
 439                 if ((!strncmp(pc, wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 440                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len)) &&
 441                  (pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == ',' ||
 442                   pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == '\0')) {
 443                         okay = 1;
 444                         continue;
 445                 }
 446                 while (*pc && *pc != ',')
 447                         pc++;
 448                 while (*pc && *pc != ' ')
 449                         pc++;
 450         }
 451
 452         /* done with him now */
 453
 454         if (wsi->c_protocol)
 455                 free(wsi->c_protocol);
 456
 457         if (!okay) {
 458                 lwsl_err("libwebsocket_client_handshake server "
 459                                         "sent bad protocol '%s'\n",
 460                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 461                 goto bail2;
 462         }
 463
 464         /*
 465          * identify the selected protocol struct and set it
 466          */
 467         n = 0;
 468         wsi->protocol = NULL;
 469         while (context->protocols[n].callback && !wsi->protocol) {  /* Stop after finding first one?? */
 470                 if (strcmp(wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 471                                            context->protocols[n].name) == 0) {
 472                         wsi->protocol = &context->protocols[n];
 473                         wsi->c_callback = wsi->protocol->callback;
 474                 }
 475                 n++;
 476         }
 477
 478         if (wsi->protocol == NULL) {
 479                 lwsl_err("libwebsocket_client_handshake server "
 480                                 "requested protocol '%s', which we "
 481                                 "said we supported but we don't!\n",
 482                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 483                 goto bail2;
 484         }
 485
 486
 487 check_extensions:
 488 #ifndef LWS_NO_EXTENSIONS
 489         /* instantiate the accepted extensions */
 490
 491         if (!wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token_len) {
 492                 lwsl_ext("no client extenstions allowed by server\n");
 493                 goto check_accept;
 494         }
 495
 496         /*
 497          * break down the list of server accepted extensions
 498          * and go through matching them or identifying bogons
 499          */
 500
 501         c = wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token;
 502         n = 0;
 503         while (more) {
 504
 505                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 506                         ext_name[n] = *c++;
 507                         if (n < sizeof(ext_name) - 1)
 508                                 n++;
 509                         continue;
 510                 }
 511                 ext_name[n] = '\0';
 512                 if (!*c)
 513                         more = 0;
 514                 else {
 515                         c++;
 516                         if (!n)
 517                                 continue;
 518                 }
 519
 520                 /* check we actually support it */
 521
 522                 lwsl_ext("checking client ext %s\n", ext_name);
 523
 524                 n = 0;
 525                 ext = wsi->protocol->owning_server->extensions;
 526                 while (ext && ext->callback) {
 527
 528                         if (strcmp(ext_name, ext->name)) {
 529                                 ext++;
 530                                 continue;
 531                         }
 532
 533                         n = 1;
 534
 535                         lwsl_ext("instantiating client ext %s\n", ext_name);
 536
 537                         /* instantiate the extension on this conn */
 538
 539                         wsi->active_extensions_user[
 540                                 wsi->count_active_extensions] =
 541                                          malloc(ext->per_session_data_size);
 542                         if (wsi->active_extensions_user[
 543                                 wsi->count_active_extensions] == NULL) {
 544                                 lwsl_err("Out of mem\n");
 545                                 goto bail2;
 546                         }
 547                         memset(wsi->active_extensions_user[
 548                                 wsi->count_active_extensions], 0,
 549                                                     ext->per_session_data_size);
 550                         wsi->active_extensions[
 551                                   wsi->count_active_extensions] = ext;
 552
 553                         /* allow him to construct his context */
 554
 555                         ext->callback(wsi->protocol->owning_server,
 556                                 ext, wsi,
 557                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 558                                         wsi->active_extensions_user[
 559                                          wsi->count_active_extensions],
 560                                                                    NULL, 0);
 561
 562                         wsi->count_active_extensions++;
 563
 564                         ext++;
 565                 }
 566
 567                 if (n == 0) {
 568                         lwsl_warn("Server said we should use"
 569                                   "an unknown extension '%s'!\n", ext_name);
 570                         goto bail2;
 571                 }
 572
 573                 n = 0;
 574         }
 575
 576 check_accept:
 577 #endif
 578
 579         /*
 580          * Confirm his accept token is the one we precomputed
 581          */
 582
 583         if (strcmp(wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 584                                   wsi->u.hdr.initial_handshake_hash_base64)) {
 585                 lwsl_warn("libwebsocket_client_handshake server "
 586                         "sent bad ACCEPT '%s' vs computed '%s'\n",
 587                         wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 588                                         wsi->u.hdr.initial_handshake_hash_base64);
 589                 goto bail2;
 590         }
 591
 592         /* allocate the per-connection user memory (if any) */
 593         if (wsi->protocol->per_session_data_size &&
 594                                           !libwebsocket_ensure_user_space(wsi))
 595                 goto bail2;
 596
 597         /* clear his proxy connection timeout */
 598
 599         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 600
 601         /* mark him as being alive */
 602
 603         wsi->state = WSI_STATE_ESTABLISHED;
 604         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 605
 606         /* union transition */
 607         memset(&wsi->u, 0, sizeof wsi->u);
 608
 609         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 610
 611         /* call him back to inform him he is up */
 612
 613         wsi->protocol->callback(context, wsi,
 614                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 615                                                      wsi->user_space, NULL, 0);
 616 #ifndef LWS_NO_EXTENSIONS
 617         /*
 618          * inform all extensions, not just active ones since they
 619          * already know
 620          */
 621
 622         ext = context->extensions;
 623
 624         while (ext && ext->callback) {
 625                 v = NULL;
 626                 for (n = 0; n < wsi->count_active_extensions; n++)
 627                         if (wsi->active_extensions[n] == ext)
 628                                 v = wsi->active_extensions_user[n];
 629
 630                 ext->callback(context, ext, wsi,
 631                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 632                 ext++;
 633         }
 634 #endif
 635
 636         return 0;
 637
 638 bail3:
 639         if (wsi->c_protocol)
 640                 free(wsi->c_protocol);
 641
 642 bail2:
 643         if (wsi->c_callback) wsi->c_callback(context, wsi,
 644        LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 645                          wsi->user_space,
 646                          NULL, 0);
 647         lwsl_info("closing connection due to bail2 connection error\n");
 648         libwebsocket_close_and_free_session(context, wsi,
 649                                                  LWS_CLOSE_STATUS_PROTOCOL_ERR);
 650
 651         return 1;
 652 }
 653
 654
 655 char *
 656 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 657                 struct libwebsocket *wsi, char *pkt)
 658 {
 659         char hash[20];
 660         char key_b64[40];
 661         char *p = pkt;
 662         int n;
 663 #ifndef LWS_NO_EXTENSIONS
 664         struct libwebsocket_extension *ext;
 665         struct libwebsocket_extension *ext1;
 666         int ext_count = 0;
 667 #endif
 668         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 669                          MAX_USER_RX_BUFFER + LWS_SEND_BUFFER_POST_PADDING];
 670         static const char magic_websocket_guid[] =
 671                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 672
 673         /*
 674          * create the random key
 675          */
 676
 677         n = libwebsockets_get_random(context, hash, 16);
 678         if (n != 16) {
 679                 lwsl_err("Unable to read from random dev %s\n",
 680                                                 SYSTEM_RANDOM_FILEPATH);
 681                 free(wsi->c_path);
 682                 free(wsi->c_host);
 683                 if (wsi->c_origin)
 684                         free(wsi->c_origin);
 685                 if (wsi->c_protocol)
 686                         free(wsi->c_protocol);
 687                 libwebsocket_close_and_free_session(context, wsi,
 688                                              LWS_CLOSE_STATUS_NOSTATUS);
 689                 return NULL;
 690         }
 691
 692         lws_b64_encode_string(hash, 16, key_b64, sizeof key_b64);
 693
 694         /*
 695          * 00 example client handshake
 696          *
 697          * GET /socket.io/websocket HTTP/1.1
 698          * Upgrade: WebSocket
 699          * Connection: Upgrade
 700          * Host: 127.0.0.1:9999
 701          * Origin: http://127.0.0.1
 702          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 703          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 704          * Cookie: socketio=websocket
 705          *
 706          * (Á®Ä0¶†≥
 707          *
 708          * 04 example client handshake
 709          *
 710          * GET /chat HTTP/1.1
 711          * Host: server.example.com
 712          * Upgrade: websocket
 713          * Connection: Upgrade
 714          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 715          * Sec-WebSocket-Origin: http://example.com
 716          * Sec-WebSocket-Protocol: chat, superchat
 717          * Sec-WebSocket-Version: 4
 718          */
 719
 720         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
 721
 722         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 723                                         "Cache-Control: no-cache\x0d\x0a");
 724
 725         p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
 726         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 727                                         "Connection: Upgrade\x0d\x0a"
 728                                         "Sec-WebSocket-Key: ");
 729         strcpy(p, key_b64);
 730         p += strlen(key_b64);
 731         p += sprintf(p, "\x0d\x0a");
 732         if (wsi->c_origin) {
 733                 if (wsi->ietf_spec_revision == 13)
 734                         p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
 735                 else
 736                         p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
 737                                                          wsi->c_origin);
 738         }
 739         if (wsi->c_protocol)
 740                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 741                                                        wsi->c_protocol);
 742
 743         /* tell the server what extensions we could support */
 744
 745         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 746 #ifndef LWS_NO_EXTENSIONS
 747         ext = context->extensions;
 748         while (ext && ext->callback) {
 749
 750                 n = 0;
 751                 ext1 = context->extensions;
 752
 753                 while (ext1 && ext1->callback) {
 754                         n |= ext1->callback(context, ext1, wsi,
 755                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 756                                         NULL, (char *)ext->name, 0);
 757
 758                         ext1++;
 759                 }
 760
 761                 if (n) { /* an extension vetos us */
 762                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 763                         ext++;
 764                         continue;
 765                 }
 766
 767                 n = context->protocols[0].callback(context, wsi,
 768                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 769                                 wsi->user_space, (char *)ext->name, 0);
 770
 771                 /*
 772                  * zero return from callback means
 773                  * go ahead and allow the extension,
 774                  * it's what we get if the callback is
 775                  * unhandled
 776                  */
 777
 778                 if (n) {
 779                         ext++;
 780                         continue;
 781                 }
 782
 783                 /* apply it */
 784
 785                 if (ext_count)
 786                         *p++ = ',';
 787                 p += sprintf(p, "%s", ext->name);
 788                 ext_count++;
 789
 790                 ext++;
 791         }
 792 #endif
 793         p += sprintf(p, "\x0d\x0a");
 794
 795         if (wsi->ietf_spec_revision)
 796                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 797                                                wsi->ietf_spec_revision);
 798
 799         /* give userland a chance to append, eg, cookies */
 800
 801         context->protocols[0].callback(context, wsi,
 802                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 803                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 804
 805         p += sprintf(p, "\x0d\x0a");
 806
 807         /* prepare the expected server accept response */
 808
 809         strcpy((char *)buf, key_b64);
 810         strcpy((char *)&buf[strlen((char *)buf)], magic_websocket_guid);
 811
 812         SHA1(buf, strlen((char *)buf), (unsigned char *)hash);
 813
 814         lws_b64_encode_string(hash, 20,
 815                         wsi->u.hdr.initial_handshake_hash_base64,
 816                              sizeof wsi->u.hdr.initial_handshake_hash_base64);
 817
 818         /* done with these now */
 819
 820         free(wsi->c_path);
 821         free(wsi->c_host);
 822         if (wsi->c_origin)
 823                 free(wsi->c_origin);
 824
 825         return p;
 826 }
 827