lib/client.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2014 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 int lws_handshake_client(struct libwebsocket *wsi, unsigned char **buf, size_t len)
  25 {
  26         int n;
  27
  28         switch (wsi->mode) {
  29         case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
  30         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
  31         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
  32         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
  33         case LWS_CONNMODE_WS_CLIENT:
  34                 for (n = 0; n < len; n++)
  35                         if (libwebsocket_client_rx_sm(wsi, *(*buf)++)) {
  36                                 lwsl_debug("client_rx_sm failed\n");
  37                                 return 1;
  38                         }
  39                 return 0;
  40         default:
  41                 break;
  42         }
  43         return 0;
  44 }
  45
  46 int lws_client_socket_service(struct libwebsocket_context *context,
  47                 struct libwebsocket *wsi, struct libwebsocket_pollfd *pollfd)
  48 {
  49         int n;
  50         char *p = (char *)&context->service_buffer[0];
  51         int len;
  52         unsigned char c;
  53
  54         switch (wsi->mode) {
  55
  56         case LWS_CONNMODE_WS_CLIENT_WAITING_CONNECT:
  57
  58                 /*
  59                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
  60                  * timeout protection set in client-handshake.c
  61                  */
  62
  63                if (libwebsocket_client_connect_2(context, wsi) == NULL) {
  64                         /* closed */
  65                         lwsl_client("closed\n");
  66                         return -1;
  67                 }
  68
  69                 /* either still pending connection, or changed mode */
  70                 return 0;
  71
  72         case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
  73
  74                 /* handle proxy hung up on us */
  75
  76                 if (pollfd->revents & LWS_POLLHUP) {
  77
  78                         lwsl_warn("Proxy connection %p (fd=%d) dead\n",
  79                                 (void *)wsi, pollfd->fd);
  80
  81                         libwebsocket_close_and_free_session(context, wsi,
  82                                                      LWS_CLOSE_STATUS_NOSTATUS);
  83                         return 0;
  84                 }
  85
  86                 n = recv(wsi->sock, context->service_buffer,
  87                                         sizeof(context->service_buffer), 0);
  88                 if (n < 0) {
  89
  90                         if (LWS_ERRNO == LWS_EAGAIN) {
  91                                 lwsl_debug(
  92                                                    "Proxy read returned EAGAIN... retrying\n");
  93                                 return 0;
  94                         }
  95
  96                         libwebsocket_close_and_free_session(context, wsi,
  97                                                      LWS_CLOSE_STATUS_NOSTATUS);
  98                         lwsl_err("ERROR reading from proxy socket\n");
  99                         return 0;
 100                 }
 101
 102                 context->service_buffer[13] = '\0';
 103                 if (strcmp((char *)context->service_buffer, "HTTP/1.0 200 ")) {
 104                         libwebsocket_close_and_free_session(context, wsi,
 105                                                      LWS_CLOSE_STATUS_NOSTATUS);
 106                         lwsl_err("ERROR proxy: %s\n", context->service_buffer);
 107                         return 0;
 108                 }
 109
 110                 /* clear his proxy connection timeout */
 111
 112                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 113
 114                 /* fallthru */
 115
 116         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
 117
 118                 /*
 119                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
 120                  * timeout protection set in client-handshake.c
 121                  */
 122
 123                 /*
 124                  * take care of our libwebsocket_callback_on_writable
 125                  * happening at a time when there's no real connection yet
 126                  */
 127                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0))
 128                         return -1;
 129
 130 #ifdef LWS_OPENSSL_SUPPORT
 131                 /* we can retry this... just cook the SSL BIO the first time */
 132
 133                 if (wsi->use_ssl && !wsi->ssl) {
 134 #if defined(CYASSL_SNI_HOST_NAME) || defined(SSL_CTRL_SET_TLSEXT_HOSTNAME)
 135                         const char *hostname = lws_hdr_simple_ptr(wsi,
 136                                                 _WSI_TOKEN_CLIENT_PEER_ADDRESS);
 137 #endif
 138
 139                         wsi->ssl = SSL_new(context->ssl_client_ctx);
 140 #ifndef USE_CYASSL
 141                         SSL_set_mode(wsi->ssl,
 142                                         SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
 143 #endif
 144                         /*
 145                          * use server name indication (SNI), if supported,
 146                          * when establishing connection
 147                          */
 148 #ifdef USE_CYASSL
 149 #ifdef CYASSL_SNI_HOST_NAME
 150                         CyaSSL_UseSNI(wsi->ssl, CYASSL_SNI_HOST_NAME,
 151                                 hostname, strlen(hostname));
 152 #endif
 153 #else
 154 #ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
 155                         SSL_set_tlsext_host_name(wsi->ssl, hostname);
 156 #endif
 157 #endif
 158
 159 #ifdef USE_CYASSL
 160                         /*
 161                          * CyaSSL does certificate verification differently
 162                          * from OpenSSL.
 163                          * If we should ignore the certificate, we need to set
 164                          * this before SSL_new and SSL_connect is called.
 165                          * Otherwise the connect will simply fail with error
 166                          * code -155
 167                          */
 168                         if (wsi->use_ssl == 2)
 169                                 CyaSSL_set_verify(wsi->ssl,
 170                                                         SSL_VERIFY_NONE, NULL);
 171 #endif /* USE_CYASSL */
 172
 173                         wsi->client_bio =
 174                                 BIO_new_socket(wsi->sock, BIO_NOCLOSE);
 175                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 176
 177 #ifdef USE_CYASSL
 178                         CyaSSL_set_using_nonblock(wsi->ssl, 1);
 179 #else
 180                         BIO_set_nbio(wsi->client_bio, 1); /* nonblocking */
 181 #endif
 182
 183                         SSL_set_ex_data(wsi->ssl,
 184                                         openssl_websocket_private_data_index,
 185                                                                        context);
 186                 }
 187
 188                 if (wsi->use_ssl) {
 189                         lws_latency_pre(context, wsi);
 190                         n = SSL_connect(wsi->ssl);
 191                         lws_latency(context, wsi,
 192                           "SSL_connect LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE",
 193                                                                       n, n > 0);
 194
 195                         if (n < 0) {
 196                                 n = SSL_get_error(wsi->ssl, n);
 197
 198                                 if (n == SSL_ERROR_WANT_READ ||
 199                                         n == SSL_ERROR_WANT_WRITE) {
 200                                         /*
 201                                          * wants us to retry connect due to
 202                                          * state of the underlying ssl layer...
 203                                          * but since it may be stalled on
 204                                          * blocked write, no incoming data may
 205                                          * arrive to trigger the retry.
 206                                          * Force (possibly many times if the SSL
 207                                          * state persists in returning the
 208                                          * condition code, but other sockets
 209                                          * are getting serviced inbetweentimes)
 210                                          * us to get called back when writable.
 211                                          */
 212
 213                                         lwsl_info(
 214                                              "SSL_connect WANT_... retrying\n");
 215                                         libwebsocket_callback_on_writable(
 216                                                                   context, wsi);
 217
 218                                         wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SSL;
 219
 220                                         return 0; /* no error */
 221                                 }
 222                                 n = -1;
 223                         }
 224
 225                         if (n <= 0) {
 226                                 /*
 227                                  * retry if new data comes until we
 228                                  * run into the connection timeout or win
 229                                  */
 230
 231                                 n = ERR_get_error();
 232                                 if (n != SSL_ERROR_NONE) {
 233                                         lwsl_err("SSL connect error %lu: %s\n",
 234                                                 n,
 235                                                 ERR_error_string(n,
 236                                                           (char *)context->service_buffer));
 237                                         return 0;
 238                                 }
 239                         }
 240                 } else
 241                         wsi->ssl = NULL;
 242
 243                 /* fallthru */
 244
 245         case LWS_CONNMODE_WS_CLIENT_WAITING_SSL:
 246
 247                 if (wsi->use_ssl) {
 248
 249                         if (wsi->mode == LWS_CONNMODE_WS_CLIENT_WAITING_SSL) {
 250                                 lws_latency_pre(context, wsi);
 251                                 n = SSL_connect(wsi->ssl);
 252                                 lws_latency(context, wsi,
 253                                                         "SSL_connect LWS_CONNMODE_WS_CLIENT_WAITING_SSL",
 254                                                         n, n > 0);
 255
 256                                 if (n < 0) {
 257                                         n = SSL_get_error(wsi->ssl, n);
 258
 259                                         if (n == SSL_ERROR_WANT_READ ||
 260                                                 n == SSL_ERROR_WANT_WRITE) {
 261                                                 /*
 262                                                  * wants us to retry connect due to
 263                                                  * state of the underlying ssl layer...
 264                                                  * but since it may be stalled on
 265                                                  * blocked write, no incoming data may
 266                                                  * arrive to trigger the retry.
 267                                                  * Force (possibly many times if the SSL
 268                                                  * state persists in returning the
 269                                                  * condition code, but other sockets
 270                                                  * are getting serviced inbetweentimes)
 271                                                  * us to get called back when writable.
 272                                                  */
 273
 274                                                 lwsl_info(
 275                                                                   "SSL_connect WANT_... retrying\n");
 276                                                 libwebsocket_callback_on_writable(
 277                                                                                                                   context, wsi);
 278
 279                                                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SSL;
 280
 281                                                 return 0; /* no error */
 282                                         }
 283                                         n = -1;
 284                                 }
 285
 286                                 if (n <= 0) {
 287                                         /*
 288                                          * retry if new data comes until we
 289                                          * run into the connection timeout or win
 290                                          */
 291                                         n = ERR_get_error();
 292                                         if (n != SSL_ERROR_NONE) {
 293                                                 lwsl_err("SSL connect error %lu: %s\n",
 294                                                                  n,
 295                                                                  ERR_error_string(n,
 296                                                                                                   (char *)context->service_buffer));
 297                                                 return 0;
 298                                         }
 299                                 }
 300                         }
 301
 302                         #ifndef USE_CYASSL
 303                         /*
 304                          * See comment above about CyaSSL certificate
 305                          * verification
 306                          */
 307                         lws_latency_pre(context, wsi);
 308                         n = SSL_get_verify_result(wsi->ssl);
 309                         lws_latency(context, wsi,
 310                                 "SSL_get_verify_result LWS_CONNMODE..HANDSHAKE",
 311                                                                       n, n > 0);
 312
 313                         if (n != X509_V_OK) {
 314                                 if ((n == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 315                                      n == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN) && wsi->use_ssl == 2) {
 316                                         lwsl_notice("accepting self-signed certificate\n");
 317                                 } else {
 318                                         lwsl_err("server's cert didn't look good, X509_V_ERR = %d: %s\n",
 319                                                  n, ERR_error_string(n, (char *)context->service_buffer));
 320                                         libwebsocket_close_and_free_session(context,
 321                                                         wsi, LWS_CLOSE_STATUS_NOSTATUS);
 322                                         return 0;
 323                                 }
 324                         }
 325 #endif /* USE_CYASSL */
 326                 } else
 327                         wsi->ssl = NULL;
 328 #endif
 329
 330                 wsi->mode = LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2;
 331                 libwebsocket_set_timeout(wsi,
 332                                 PENDING_TIMEOUT_AWAITING_CLIENT_HS_SEND,
 333                                                               AWAITING_TIMEOUT);
 334
 335                 /* fallthru */
 336
 337         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2:
 338                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 339                 if (p == NULL) {
 340                         lwsl_err("Failed to generate handshake for client\n");
 341                         libwebsocket_close_and_free_session(context, wsi,
 342                                                      LWS_CLOSE_STATUS_NOSTATUS);
 343                         return 0;
 344                 }
 345
 346                 /* send our request to the server */
 347
 348                 lws_latency_pre(context, wsi);
 349
 350                 n = lws_ssl_capable_write(wsi, context->service_buffer, p - (char *)context->service_buffer);
 351                 lws_latency(context, wsi, "send lws_issue_raw", n, n == p - (char *)context->service_buffer);
 352                 switch (n) {
 353                 case LWS_SSL_CAPABLE_ERROR:
 354                         lwsl_debug("ERROR writing to client socket\n");
 355                         libwebsocket_close_and_free_session(context, wsi,
 356                                                      LWS_CLOSE_STATUS_NOSTATUS);
 357                         return 0;
 358                 case LWS_SSL_CAPABLE_MORE_SERVICE:
 359                         libwebsocket_callback_on_writable(context, wsi);
 360                         break;
 361                 }
 362
 363                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 364                 wsi->u.hdr.lextable_pos = 0;
 365                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 366                 libwebsocket_set_timeout(wsi,
 367                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE,
 368                                                               AWAITING_TIMEOUT);
 369                 break;
 370
 371         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 372
 373                 /* handle server hung up on us */
 374
 375                 if (pollfd->revents & LWS_POLLHUP) {
 376
 377                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 378                                 (void *)wsi, pollfd->fd);
 379
 380                         goto bail3;
 381                 }
 382
 383                 if (!(pollfd->revents & LWS_POLLIN))
 384                         break;
 385
 386                 /* interpret the server response */
 387
 388                 /*
 389                  *  HTTP/1.1 101 Switching Protocols
 390                  *  Upgrade: websocket
 391                  *  Connection: Upgrade
 392                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 393                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 394                  *  Sec-WebSocket-Protocol: chat
 395                  */
 396
 397                 /*
 398                  * we have to take some care here to only take from the
 399                  * socket bytewise.  The browser may (and has been seen to
 400                  * in the case that onopen() performs websocket traffic)
 401                  * coalesce both handshake response and websocket traffic
 402                  * in one packet, since at that point the connection is
 403                  * definitively ready from browser pov.
 404                  */
 405                 len = 1;
 406                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE &&
 407                                                                       len > 0) {
 408                         n = lws_ssl_capable_read(context, wsi, &c, 1);
 409                         lws_latency(context, wsi, "send lws_issue_raw", n, n == 1);
 410                         switch (n) {
 411                         case LWS_SSL_CAPABLE_ERROR:
 412                                 goto bail3;
 413                         case LWS_SSL_CAPABLE_MORE_SERVICE:
 414                                 return 0;
 415                         }
 416
 417                         if (libwebsocket_parse(context, wsi, c)) {
 418                                 lwsl_warn("problems parsing header\n");
 419                                 goto bail3;
 420                         }
 421                 }
 422
 423                 /*
 424                  * hs may also be coming in multiple packets, there is a 5-sec
 425                  * libwebsocket timeout still active here too, so if parsing did
 426                  * not complete just wait for next packet coming in this state
 427                  */
 428
 429                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 430                         break;
 431
 432                 /*
 433                  * otherwise deal with the handshake.  If there's any
 434                  * packet traffic already arrived we'll trigger poll() again
 435                  * right away and deal with it that way
 436                  */
 437
 438                 return lws_client_interpret_server_handshake(context, wsi);
 439
 440 bail3:
 441                 lwsl_info(
 442                         "closing connection at LWS_CONNMODE...SERVER_REPLY\n");
 443                 libwebsocket_close_and_free_session(context, wsi,
 444                                                     LWS_CLOSE_STATUS_NOSTATUS);
 445                 return -1;
 446
 447         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 448                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 449                 break;
 450
 451         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 452                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 453                 break;
 454         default:
 455                 break;
 456         }
 457
 458         return 0;
 459 }
 460
 461
 462 /*
 463  * In-place str to lower case
 464  */
 465
 466 static void
 467 strtolower(char *s)
 468 {
 469         while (*s) {
 470                 *s = tolower((int)*s);
 471                 s++;
 472         }
 473 }
 474
 475 int
 476 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 477                 struct libwebsocket *wsi)
 478 {
 479         const char *pc;
 480         int okay = 0;
 481         char *p;
 482         int len;
 483 #ifndef LWS_NO_EXTENSIONS
 484         char ext_name[128];
 485         struct libwebsocket_extension *ext;
 486         void *v;
 487         int more = 1;
 488         const char *c;
 489 #endif
 490         int n;
 491         int close_reason = LWS_CLOSE_STATUS_PROTOCOL_ERR;
 492
 493         /*
 494          * well, what the server sent looked reasonable for syntax.
 495          * Now let's confirm it sent all the necessary headers
 496          */
 497
 498         if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0) {
 499                 lwsl_info("no ACCEPT\n");
 500                 goto bail3;
 501         }
 502
 503         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 504         if (!p) {
 505                 lwsl_info("no URI\n");
 506                 goto bail3;
 507         }
 508         if (p && strncmp(p, "101", 3)) {
 509                 lwsl_warn(
 510                        "lws_client_handshake: got bad HTTP response '%s'\n", p);
 511                 goto bail3;
 512         }
 513
 514         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
 515         if (!p) {
 516                 lwsl_info("no UPGRADE\n");
 517                 goto bail3;
 518         }
 519         strtolower(p);
 520         if (strcmp(p, "websocket")) {
 521                 lwsl_warn(
 522                       "lws_client_handshake: got bad Upgrade header '%s'\n", p);
 523                 goto bail3;
 524         }
 525
 526         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
 527         if (!p) {
 528                 lwsl_info("no Connection hdr\n");
 529                 goto bail3;
 530         }
 531         strtolower(p);
 532         if (strcmp(p, "upgrade")) {
 533                 lwsl_warn("lws_client_int_s_hs: bad header %s\n", p);
 534                 goto bail3;
 535         }
 536
 537         pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);
 538         if (pc == NULL)
 539                 lwsl_parser("lws_client_int_s_hs: no protocol list\n");
 540         else
 541                 lwsl_parser("lws_client_int_s_hs: protocol list '%s'\n", pc);
 542
 543         /*
 544          * confirm the protocol the server wants to talk was in the list
 545          * of protocols we offered
 546          */
 547
 548         len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
 549         if (!len) {
 550
 551                 lwsl_info("lws_client_int_s_hs: WSI_TOKEN_PROTOCOL is null\n");
 552                 /*
 553                  * no protocol name to work from,
 554                  * default to first protocol
 555                  */
 556                 wsi->protocol = &context->protocols[0];
 557                 goto check_extensions;
 558         }
 559
 560         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
 561         len = strlen(p);
 562
 563         while (*pc && !okay) {
 564                 if (!strncmp(pc, p, len) &&
 565                                           (pc[len] == ',' || pc[len] == '\0')) {
 566                         okay = 1;
 567                         continue;
 568                 }
 569                 while (*pc && *pc != ',')
 570                         pc++;
 571                 while (*pc && *pc == ' ')
 572                         pc++;
 573         }
 574
 575         if (!okay) {
 576                 lwsl_err("lws_client_int_s_hs: got bad protocol '%s'\n", p);
 577                 goto bail2;
 578         }
 579
 580         /*
 581          * identify the selected protocol struct and set it
 582          */
 583         n = 0;
 584         wsi->protocol = NULL;
 585         while (context->protocols[n].callback && !wsi->protocol) {
 586                 if (strcmp(p, context->protocols[n].name) == 0) {
 587                         wsi->protocol = &context->protocols[n];
 588                         break;
 589                 }
 590                 n++;
 591         }
 592
 593         if (wsi->protocol == NULL) {
 594                 lwsl_err("lws_client_int_s_hs: fail protocol '%s'\n", p);
 595                 goto bail2;
 596         }
 597
 598
 599 check_extensions:
 600 #ifndef LWS_NO_EXTENSIONS
 601         /* instantiate the accepted extensions */
 602
 603         if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
 604                 lwsl_ext("no client extenstions allowed by server\n");
 605                 goto check_accept;
 606         }
 607
 608         /*
 609          * break down the list of server accepted extensions
 610          * and go through matching them or identifying bogons
 611          */
 612
 613         if (lws_hdr_copy(wsi, (char *)context->service_buffer,
 614                    sizeof(context->service_buffer), WSI_TOKEN_EXTENSIONS) < 0) {
 615                 lwsl_warn("ext list from server failed to copy\n");
 616                 goto bail2;
 617         }
 618
 619         c = (char *)context->service_buffer;
 620         n = 0;
 621         while (more) {
 622
 623                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 624                         ext_name[n] = *c++;
 625                         if (n < sizeof(ext_name) - 1)
 626                                 n++;
 627                         continue;
 628                 }
 629                 ext_name[n] = '\0';
 630                 if (!*c)
 631                         more = 0;
 632                 else {
 633                         c++;
 634                         if (!n)
 635                                 continue;
 636                 }
 637
 638                 /* check we actually support it */
 639
 640                 lwsl_ext("checking client ext %s\n", ext_name);
 641
 642                 n = 0;
 643                 ext = wsi->protocol->owning_server->extensions;
 644                 while (ext && ext->callback) {
 645
 646                         if (strcmp(ext_name, ext->name)) {
 647                                 ext++;
 648                                 continue;
 649                         }
 650
 651                         n = 1;
 652
 653                         lwsl_ext("instantiating client ext %s\n", ext_name);
 654
 655                         /* instantiate the extension on this conn */
 656
 657                         wsi->active_extensions_user[
 658                                 wsi->count_active_extensions] =
 659                                          malloc(ext->per_session_data_size);
 660                         if (wsi->active_extensions_user[
 661                                 wsi->count_active_extensions] == NULL) {
 662                                 lwsl_err("Out of mem\n");
 663                                 goto bail2;
 664                         }
 665                         memset(wsi->active_extensions_user[
 666                                 wsi->count_active_extensions], 0,
 667                                                     ext->per_session_data_size);
 668                         wsi->active_extensions[
 669                                   wsi->count_active_extensions] = ext;
 670
 671                         /* allow him to construct his context */
 672
 673                         ext->callback(wsi->protocol->owning_server,
 674                                 ext, wsi,
 675                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 676                                         wsi->active_extensions_user[
 677                                          wsi->count_active_extensions],
 678                                                                    NULL, 0);
 679
 680                         wsi->count_active_extensions++;
 681
 682                         ext++;
 683                 }
 684
 685                 if (n == 0) {
 686                         lwsl_warn("Unknown ext '%s'!\n", ext_name);
 687                         goto bail2;
 688                 }
 689
 690                 n = 0;
 691         }
 692
 693 check_accept:
 694 #endif
 695
 696         /*
 697          * Confirm his accept token is the one we precomputed
 698          */
 699
 700         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
 701         if (strcmp(p, wsi->u.hdr.ah->initial_handshake_hash_base64)) {
 702                 lwsl_warn("lws_client_int_s_hs: accept %s wrong vs %s\n", p,
 703                                   wsi->u.hdr.ah->initial_handshake_hash_base64);
 704                 goto bail2;
 705         }
 706
 707         /* allocate the per-connection user memory (if any) */
 708         if (libwebsocket_ensure_user_space(wsi)) {
 709                 lwsl_err("Problem allocating wsi user mem\n");
 710                 goto bail2;
 711         }
 712
 713         /*
 714          * we seem to be good to go, give client last chance to check
 715          * headers and OK it
 716          */
 717
 718         wsi->protocol->callback(context, wsi,
 719                                 LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
 720                                                      wsi->user_space, NULL, 0);
 721
 722         /* clear his proxy connection timeout */
 723
 724         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 725
 726         /* free up his parsing allocations */
 727
 728         if (wsi->u.hdr.ah)
 729                 free(wsi->u.hdr.ah);
 730
 731         lws_union_transition(wsi, LWS_CONNMODE_WS_CLIENT);
 732         wsi->state = WSI_STATE_ESTABLISHED;
 733
 734         wsi->rxflow_change_to = LWS_RXFLOW_ALLOW;
 735
 736         /*
 737          * create the frame buffer for this connection according to the
 738          * size mentioned in the protocol definition.  If 0 there, then
 739          * use a big default for compatibility
 740          */
 741
 742         n = wsi->protocol->rx_buffer_size;
 743         if (!n)
 744                 n = LWS_MAX_SOCKET_IO_BUF;
 745         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 746         wsi->u.ws.rx_user_buffer = malloc(n);
 747         if (!wsi->u.ws.rx_user_buffer) {
 748                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 749                 goto bail2;
 750         }
 751         lwsl_info("Allocating client RX buffer %d\n", n);
 752
 753         if (setsockopt(wsi->sock, SOL_SOCKET, SO_SNDBUF, (const char *)&n, sizeof n)) {
 754                 lwsl_warn("Failed to set SNDBUF to %d", n);
 755                 goto bail3;
 756         }
 757
 758         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 759
 760         /* call him back to inform him he is up */
 761
 762         wsi->protocol->callback(context, wsi,
 763                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 764                                                      wsi->user_space, NULL, 0);
 765 #ifndef LWS_NO_EXTENSIONS
 766         /*
 767          * inform all extensions, not just active ones since they
 768          * already know
 769          */
 770
 771         ext = context->extensions;
 772
 773         while (ext && ext->callback) {
 774                 v = NULL;
 775                 for (n = 0; n < wsi->count_active_extensions; n++)
 776                         if (wsi->active_extensions[n] == ext)
 777                                 v = wsi->active_extensions_user[n];
 778
 779                 ext->callback(context, ext, wsi,
 780                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 781                 ext++;
 782         }
 783 #endif
 784
 785         return 0;
 786
 787 bail3:
 788         free(wsi->u.ws.rx_user_buffer);
 789         wsi->u.ws.rx_user_buffer = NULL;
 790         close_reason = LWS_CLOSE_STATUS_NOSTATUS;
 791
 792 bail2:
 793         if (wsi->protocol)
 794                 wsi->protocol->callback(context, wsi,
 795                         LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 796                                                       wsi->user_space, NULL, 0);
 797
 798         lwsl_info("closing connection due to bail2 connection error\n");
 799
 800         /* free up his parsing allocations */
 801
 802         if (wsi->u.hdr.ah)
 803                 free(wsi->u.hdr.ah);
 804
 805         libwebsocket_close_and_free_session(context, wsi, close_reason);
 806
 807         return 1;
 808 }
 809
 810
 811 char *
 812 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 813                 struct libwebsocket *wsi, char *pkt)
 814 {
 815         char buf[128];
 816         char hash[20];
 817         char key_b64[40];
 818         char *p = pkt;
 819         int n;
 820 #ifndef LWS_NO_EXTENSIONS
 821         struct libwebsocket_extension *ext;
 822         int ext_count = 0;
 823 #endif
 824
 825         /*
 826          * create the random key
 827          */
 828
 829         n = libwebsockets_get_random(context, hash, 16);
 830         if (n != 16) {
 831                 lwsl_err("Unable to read from random dev %s\n",
 832                                                 SYSTEM_RANDOM_FILEPATH);
 833                 libwebsocket_close_and_free_session(context, wsi,
 834                                              LWS_CLOSE_STATUS_NOSTATUS);
 835                 return NULL;
 836         }
 837
 838         lws_b64_encode_string(hash, 16, key_b64, sizeof(key_b64));
 839
 840         /*
 841          * 00 example client handshake
 842          *
 843          * GET /socket.io/websocket HTTP/1.1
 844          * Upgrade: WebSocket
 845          * Connection: Upgrade
 846          * Host: 127.0.0.1:9999
 847          * Origin: http://127.0.0.1
 848          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 849          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 850          * Cookie: socketio=websocket
 851          *
 852          * (Á®Ä0¶†≥
 853          *
 854          * 04 example client handshake
 855          *
 856          * GET /chat HTTP/1.1
 857          * Host: server.example.com
 858          * Upgrade: websocket
 859          * Connection: Upgrade
 860          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 861          * Sec-WebSocket-Origin: http://example.com
 862          * Sec-WebSocket-Protocol: chat, superchat
 863          * Sec-WebSocket-Version: 4
 864          */
 865
 866         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a",
 867                                 lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_URI));
 868
 869         p += sprintf(p,
 870                 "Pragma: no-cache\x0d\x0a""Cache-Control: no-cache\x0d\x0a");
 871
 872         p += sprintf(p, "Host: %s\x0d\x0a",
 873                                lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_HOST));
 874         p += sprintf(p,
 875 "Upgrade: websocket\x0d\x0a""Connection: Upgrade\x0d\x0a""Sec-WebSocket-Key: ");
 876         strcpy(p, key_b64);
 877         p += strlen(key_b64);
 878         p += sprintf(p, "\x0d\x0a");
 879         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN))
 880                 p += sprintf(p, "Origin: http://%s\x0d\x0a",
 881                              lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN));
 882
 883         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))
 884                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 885                      lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));
 886
 887         /* tell the server what extensions we could support */
 888
 889         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 890 #ifndef LWS_NO_EXTENSIONS
 891         ext = context->extensions;
 892         while (ext && ext->callback) {
 893
 894                 n = lws_ext_callback_for_each_extension_type(context, wsi,
 895                            LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 896                                                           (char *)ext->name, 0);
 897                 if (n) { /* an extension vetos us */
 898                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 899                         ext++;
 900                         continue;
 901                 }
 902
 903                 n = context->protocols[0].callback(context, wsi,
 904                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 905                                 wsi->user_space, (char *)ext->name, 0);
 906
 907                 /*
 908                  * zero return from callback means
 909                  * go ahead and allow the extension,
 910                  * it's what we get if the callback is
 911                  * unhandled
 912                  */
 913
 914                 if (n) {
 915                         ext++;
 916                         continue;
 917                 }
 918
 919                 /* apply it */
 920
 921                 if (ext_count)
 922                         *p++ = ',';
 923                 p += sprintf(p, "%s", ext->name);
 924                 ext_count++;
 925
 926                 ext++;
 927         }
 928 #endif
 929         p += sprintf(p, "\x0d\x0a");
 930
 931         if (wsi->ietf_spec_revision)
 932                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 933                                                wsi->ietf_spec_revision);
 934
 935         /* give userland a chance to append, eg, cookies */
 936
 937         context->protocols[0].callback(context, wsi,
 938                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 939                 NULL, &p, (pkt + sizeof(context->service_buffer)) - p - 12);
 940
 941         p += sprintf(p, "\x0d\x0a");
 942
 943         /* prepare the expected server accept response */
 944
 945         key_b64[39] = '\0'; /* enforce composed length below buf sizeof */
 946         n = sprintf(buf, "%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", key_b64);
 947
 948         libwebsockets_SHA1((unsigned char *)buf, n, (unsigned char *)hash);
 949
 950         lws_b64_encode_string(hash, 20,
 951                         wsi->u.hdr.ah->initial_handshake_hash_base64,
 952                           sizeof(wsi->u.hdr.ah->initial_handshake_hash_base64));
 953
 954         return p;
 955 }
 956