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 || n == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN) && wsi->use_ssl == 2) {
 315                                         lwsl_notice("accepting self-signed certificate\n");
 316                                 } else {
 317                                         lwsl_err(
 318                                                 "server's cert didn't look good %d\n", n);
 319                                         libwebsocket_close_and_free_session(context,
 320                                                         wsi, LWS_CLOSE_STATUS_NOSTATUS);
 321                                         return 0;
 322                                 }
 323                         }
 324 #endif /* USE_CYASSL */
 325                 } else
 326                         wsi->ssl = NULL;
 327 #endif
 328
 329                 wsi->mode = LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2;
 330                 libwebsocket_set_timeout(wsi,
 331                                 PENDING_TIMEOUT_AWAITING_CLIENT_HS_SEND,
 332                                                               AWAITING_TIMEOUT);
 333
 334                 /* fallthru */
 335
 336         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2:
 337                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 338                 if (p == NULL) {
 339                         lwsl_err("Failed to generate handshake for client\n");
 340                         libwebsocket_close_and_free_session(context, wsi,
 341                                                      LWS_CLOSE_STATUS_NOSTATUS);
 342                         return 0;
 343                 }
 344
 345                 /* send our request to the server */
 346
 347                 lws_latency_pre(context, wsi);
 348
 349                 n = lws_ssl_capable_write(wsi, context->service_buffer, p - (char *)context->service_buffer);
 350                 lws_latency(context, wsi, "send lws_issue_raw", n, n == p - (char *)context->service_buffer);
 351                 switch (n) {
 352                 case LWS_SSL_CAPABLE_ERROR:
 353                         lwsl_debug("ERROR writing to client socket\n");
 354                         libwebsocket_close_and_free_session(context, wsi,
 355                                                      LWS_CLOSE_STATUS_NOSTATUS);
 356                         return 0;
 357                 case LWS_SSL_CAPABLE_MORE_SERVICE:
 358                         libwebsocket_callback_on_writable(context, wsi);
 359                         break;
 360                 }
 361
 362                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 363                 wsi->u.hdr.lextable_pos = 0;
 364                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 365                 libwebsocket_set_timeout(wsi,
 366                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE,
 367                                                               AWAITING_TIMEOUT);
 368                 break;
 369
 370         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 371
 372                 /* handle server hung up on us */
 373
 374                 if (pollfd->revents & LWS_POLLHUP) {
 375
 376                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 377                                 (void *)wsi, pollfd->fd);
 378
 379                         goto bail3;
 380                 }
 381
 382                 if (!(pollfd->revents & LWS_POLLIN))
 383                         break;
 384
 385                 /* interpret the server response */
 386
 387                 /*
 388                  *  HTTP/1.1 101 Switching Protocols
 389                  *  Upgrade: websocket
 390                  *  Connection: Upgrade
 391                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 392                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 393                  *  Sec-WebSocket-Protocol: chat
 394                  */
 395
 396                 /*
 397                  * we have to take some care here to only take from the
 398                  * socket bytewise.  The browser may (and has been seen to
 399                  * in the case that onopen() performs websocket traffic)
 400                  * coalesce both handshake response and websocket traffic
 401                  * in one packet, since at that point the connection is
 402                  * definitively ready from browser pov.
 403                  */
 404                 len = 1;
 405                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE &&
 406                                                                       len > 0) {
 407                         n = lws_ssl_capable_read(context, wsi, &c, 1);
 408                         lws_latency(context, wsi, "send lws_issue_raw", n, n == 1);
 409                         switch (n) {
 410                         case LWS_SSL_CAPABLE_ERROR:
 411                                 goto bail3;
 412                         case LWS_SSL_CAPABLE_MORE_SERVICE:
 413                                 return 0;
 414                         }
 415
 416                         if (libwebsocket_parse(context, wsi, c)) {
 417                                 lwsl_warn("problems parsing header\n");
 418                                 goto bail3;
 419                         }
 420                 }
 421
 422                 /*
 423                  * hs may also be coming in multiple packets, there is a 5-sec
 424                  * libwebsocket timeout still active here too, so if parsing did
 425                  * not complete just wait for next packet coming in this state
 426                  */
 427
 428                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 429                         break;
 430
 431                 /*
 432                  * otherwise deal with the handshake.  If there's any
 433                  * packet traffic already arrived we'll trigger poll() again
 434                  * right away and deal with it that way
 435                  */
 436
 437                 return lws_client_interpret_server_handshake(context, wsi);
 438
 439 bail3:
 440                 lwsl_info(
 441                         "closing connection at LWS_CONNMODE...SERVER_REPLY\n");
 442                 libwebsocket_close_and_free_session(context, wsi,
 443                                                     LWS_CLOSE_STATUS_NOSTATUS);
 444                 return -1;
 445
 446         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 447                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 448                 break;
 449
 450         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 451                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 452                 break;
 453         default:
 454                 break;
 455         }
 456
 457         return 0;
 458 }
 459
 460
 461 /*
 462  * In-place str to lower case
 463  */
 464
 465 static void
 466 strtolower(char *s)
 467 {
 468         while (*s) {
 469                 *s = tolower((int)*s);
 470                 s++;
 471         }
 472 }
 473
 474 int
 475 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 476                 struct libwebsocket *wsi)
 477 {
 478         const char *pc;
 479         int okay = 0;
 480         char *p;
 481         int len;
 482 #ifndef LWS_NO_EXTENSIONS
 483         char ext_name[128];
 484         struct libwebsocket_extension *ext;
 485         void *v;
 486         int more = 1;
 487         const char *c;
 488 #endif
 489         int n;
 490         int close_reason = LWS_CLOSE_STATUS_PROTOCOL_ERR;
 491
 492         /*
 493          * well, what the server sent looked reasonable for syntax.
 494          * Now let's confirm it sent all the necessary headers
 495          */
 496
 497         if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0) {
 498                 lwsl_info("no ACCEPT\n");
 499                 goto bail3;
 500         }
 501
 502         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 503         if (!p) {
 504                 lwsl_info("no URI\n");
 505                 goto bail3;
 506         }
 507         if (p && strncmp(p, "101", 3)) {
 508                 lwsl_warn(
 509                        "lws_client_handshake: got bad HTTP response '%s'\n", p);
 510                 goto bail3;
 511         }
 512
 513         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
 514         if (!p) {
 515                 lwsl_info("no UPGRADE\n");
 516                 goto bail3;
 517         }
 518         strtolower(p);
 519         if (strcmp(p, "websocket")) {
 520                 lwsl_warn(
 521                       "lws_client_handshake: got bad Upgrade header '%s'\n", p);
 522                 goto bail3;
 523         }
 524
 525         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
 526         if (!p) {
 527                 lwsl_info("no Connection hdr\n");
 528                 goto bail3;
 529         }
 530         strtolower(p);
 531         if (strcmp(p, "upgrade")) {
 532                 lwsl_warn("lws_client_int_s_hs: bad header %s\n", p);
 533                 goto bail3;
 534         }
 535
 536         pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);
 537         if (pc == NULL)
 538                 lwsl_parser("lws_client_int_s_hs: no protocol list\n");
 539         else
 540                 lwsl_parser("lws_client_int_s_hs: protocol list '%s'\n", pc);
 541
 542         /*
 543          * confirm the protocol the server wants to talk was in the list
 544          * of protocols we offered
 545          */
 546
 547         len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
 548         if (!len) {
 549
 550                 lwsl_info("lws_client_int_s_hs: WSI_TOKEN_PROTOCOL is null\n");
 551                 /*
 552                  * no protocol name to work from,
 553                  * default to first protocol
 554                  */
 555                 wsi->protocol = &context->protocols[0];
 556                 goto check_extensions;
 557         }
 558
 559         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
 560         len = strlen(p);
 561
 562         while (*pc && !okay) {
 563                 if (!strncmp(pc, p, len) &&
 564                                           (pc[len] == ',' || pc[len] == '\0')) {
 565                         okay = 1;
 566                         continue;
 567                 }
 568                 while (*pc && *pc != ',')
 569                         pc++;
 570                 while (*pc && *pc == ' ')
 571                         pc++;
 572         }
 573
 574         if (!okay) {
 575                 lwsl_err("lws_client_int_s_hs: got bad protocol '%s'\n", p);
 576                 goto bail2;
 577         }
 578
 579         /*
 580          * identify the selected protocol struct and set it
 581          */
 582         n = 0;
 583         wsi->protocol = NULL;
 584         while (context->protocols[n].callback && !wsi->protocol) {
 585                 if (strcmp(p, context->protocols[n].name) == 0) {
 586                         wsi->protocol = &context->protocols[n];
 587                         break;
 588                 }
 589                 n++;
 590         }
 591
 592         if (wsi->protocol == NULL) {
 593                 lwsl_err("lws_client_int_s_hs: fail protocol '%s'\n", p);
 594                 goto bail2;
 595         }
 596
 597
 598 check_extensions:
 599 #ifndef LWS_NO_EXTENSIONS
 600         /* instantiate the accepted extensions */
 601
 602         if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
 603                 lwsl_ext("no client extenstions allowed by server\n");
 604                 goto check_accept;
 605         }
 606
 607         /*
 608          * break down the list of server accepted extensions
 609          * and go through matching them or identifying bogons
 610          */
 611
 612         if (lws_hdr_copy(wsi, (char *)context->service_buffer,
 613                    sizeof(context->service_buffer), WSI_TOKEN_EXTENSIONS) < 0) {
 614                 lwsl_warn("ext list from server failed to copy\n");
 615                 goto bail2;
 616         }
 617
 618         c = (char *)context->service_buffer;
 619         n = 0;
 620         while (more) {
 621
 622                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 623                         ext_name[n] = *c++;
 624                         if (n < sizeof(ext_name) - 1)
 625                                 n++;
 626                         continue;
 627                 }
 628                 ext_name[n] = '\0';
 629                 if (!*c)
 630                         more = 0;
 631                 else {
 632                         c++;
 633                         if (!n)
 634                                 continue;
 635                 }
 636
 637                 /* check we actually support it */
 638
 639                 lwsl_ext("checking client ext %s\n", ext_name);
 640
 641                 n = 0;
 642                 ext = wsi->protocol->owning_server->extensions;
 643                 while (ext && ext->callback) {
 644
 645                         if (strcmp(ext_name, ext->name)) {
 646                                 ext++;
 647                                 continue;
 648                         }
 649
 650                         n = 1;
 651
 652                         lwsl_ext("instantiating client ext %s\n", ext_name);
 653
 654                         /* instantiate the extension on this conn */
 655
 656                         wsi->active_extensions_user[
 657                                 wsi->count_active_extensions] =
 658                                          malloc(ext->per_session_data_size);
 659                         if (wsi->active_extensions_user[
 660                                 wsi->count_active_extensions] == NULL) {
 661                                 lwsl_err("Out of mem\n");
 662                                 goto bail2;
 663                         }
 664                         memset(wsi->active_extensions_user[
 665                                 wsi->count_active_extensions], 0,
 666                                                     ext->per_session_data_size);
 667                         wsi->active_extensions[
 668                                   wsi->count_active_extensions] = ext;
 669
 670                         /* allow him to construct his context */
 671
 672                         ext->callback(wsi->protocol->owning_server,
 673                                 ext, wsi,
 674                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 675                                         wsi->active_extensions_user[
 676                                          wsi->count_active_extensions],
 677                                                                    NULL, 0);
 678
 679                         wsi->count_active_extensions++;
 680
 681                         ext++;
 682                 }
 683
 684                 if (n == 0) {
 685                         lwsl_warn("Unknown ext '%s'!\n", ext_name);
 686                         goto bail2;
 687                 }
 688
 689                 n = 0;
 690         }
 691
 692 check_accept:
 693 #endif
 694
 695         /*
 696          * Confirm his accept token is the one we precomputed
 697          */
 698
 699         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
 700         if (strcmp(p, wsi->u.hdr.ah->initial_handshake_hash_base64)) {
 701                 lwsl_warn("lws_client_int_s_hs: accept %s wrong vs %s\n", p,
 702                                   wsi->u.hdr.ah->initial_handshake_hash_base64);
 703                 goto bail2;
 704         }
 705
 706         /* allocate the per-connection user memory (if any) */
 707         if (libwebsocket_ensure_user_space(wsi)) {
 708                 lwsl_err("Problem allocating wsi user mem\n");
 709                 goto bail2;
 710         }
 711
 712         /*
 713          * we seem to be good to go, give client last chance to check
 714          * headers and OK it
 715          */
 716
 717         wsi->protocol->callback(context, wsi,
 718                                 LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
 719                                                      wsi->user_space, NULL, 0);
 720
 721         /* clear his proxy connection timeout */
 722
 723         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 724
 725         /* free up his parsing allocations */
 726         if (wsi->u.hdr.ah)
 727                 free(wsi->u.hdr.ah);
 728
 729         /* mark him as being alive */
 730
 731         wsi->state = WSI_STATE_ESTABLISHED;
 732         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 733
 734         /* union transition */
 735
 736         memset(&wsi->u, 0, sizeof(wsi->u));
 737
 738         wsi->rxflow_change_to = LWS_RXFLOW_ALLOW;
 739
 740         /*
 741          * create the frame buffer for this connection according to the
 742          * size mentioned in the protocol definition.  If 0 there, then
 743          * use a big default for compatibility
 744          */
 745
 746         n = wsi->protocol->rx_buffer_size;
 747         if (!n)
 748                 n = LWS_MAX_SOCKET_IO_BUF;
 749         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 750         wsi->u.ws.rx_user_buffer = malloc(n);
 751         if (!wsi->u.ws.rx_user_buffer) {
 752                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 753                 goto bail2;
 754         }
 755         lwsl_info("Allocating client RX buffer %d\n", n);
 756
 757         if (setsockopt(wsi->sock, SOL_SOCKET, SO_SNDBUF, (const char *)&n, sizeof n)) {
 758                 lwsl_warn("Failed to set SNDBUF to %d", n);
 759                 goto bail3;
 760         }
 761
 762         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 763
 764         /* call him back to inform him he is up */
 765
 766         wsi->protocol->callback(context, wsi,
 767                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 768                                                      wsi->user_space, NULL, 0);
 769 #ifndef LWS_NO_EXTENSIONS
 770         /*
 771          * inform all extensions, not just active ones since they
 772          * already know
 773          */
 774
 775         ext = context->extensions;
 776
 777         while (ext && ext->callback) {
 778                 v = NULL;
 779                 for (n = 0; n < wsi->count_active_extensions; n++)
 780                         if (wsi->active_extensions[n] == ext)
 781                                 v = wsi->active_extensions_user[n];
 782
 783                 ext->callback(context, ext, wsi,
 784                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 785                 ext++;
 786         }
 787 #endif
 788
 789         return 0;
 790
 791 bail3:
 792         free(wsi->u.ws.rx_user_buffer);
 793         wsi->u.ws.rx_user_buffer = NULL;
 794         close_reason = LWS_CLOSE_STATUS_NOSTATUS;
 795
 796 bail2:
 797         if (wsi->protocol)
 798                 wsi->protocol->callback(context, wsi,
 799                         LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 800                                                       wsi->user_space, NULL, 0);
 801
 802         lwsl_info("closing connection due to bail2 connection error\n");
 803
 804         /* free up his parsing allocations */
 805
 806         if (wsi->u.hdr.ah)
 807                 free(wsi->u.hdr.ah);
 808
 809         libwebsocket_close_and_free_session(context, wsi, close_reason);
 810
 811         return 1;
 812 }
 813
 814
 815 char *
 816 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 817                 struct libwebsocket *wsi, char *pkt)
 818 {
 819         char buf[128];
 820         char hash[20];
 821         char key_b64[40];
 822         char *p = pkt;
 823         int n;
 824 #ifndef LWS_NO_EXTENSIONS
 825         struct libwebsocket_extension *ext;
 826         int ext_count = 0;
 827 #endif
 828
 829         /*
 830          * create the random key
 831          */
 832
 833         n = libwebsockets_get_random(context, hash, 16);
 834         if (n != 16) {
 835                 lwsl_err("Unable to read from random dev %s\n",
 836                                                 SYSTEM_RANDOM_FILEPATH);
 837                 libwebsocket_close_and_free_session(context, wsi,
 838                                              LWS_CLOSE_STATUS_NOSTATUS);
 839                 return NULL;
 840         }
 841
 842         lws_b64_encode_string(hash, 16, key_b64, sizeof(key_b64));
 843
 844         /*
 845          * 00 example client handshake
 846          *
 847          * GET /socket.io/websocket HTTP/1.1
 848          * Upgrade: WebSocket
 849          * Connection: Upgrade
 850          * Host: 127.0.0.1:9999
 851          * Origin: http://127.0.0.1
 852          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 853          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 854          * Cookie: socketio=websocket
 855          *
 856          * (Á®Ä0¶†≥
 857          *
 858          * 04 example client handshake
 859          *
 860          * GET /chat HTTP/1.1
 861          * Host: server.example.com
 862          * Upgrade: websocket
 863          * Connection: Upgrade
 864          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 865          * Sec-WebSocket-Origin: http://example.com
 866          * Sec-WebSocket-Protocol: chat, superchat
 867          * Sec-WebSocket-Version: 4
 868          */
 869
 870         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a",
 871                                 lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_URI));
 872
 873         p += sprintf(p,
 874                 "Pragma: no-cache\x0d\x0a""Cache-Control: no-cache\x0d\x0a");
 875
 876         p += sprintf(p, "Host: %s\x0d\x0a",
 877                                lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_HOST));
 878         p += sprintf(p,
 879 "Upgrade: websocket\x0d\x0a""Connection: Upgrade\x0d\x0a""Sec-WebSocket-Key: ");
 880         strcpy(p, key_b64);
 881         p += strlen(key_b64);
 882         p += sprintf(p, "\x0d\x0a");
 883         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN))
 884                 p += sprintf(p, "Origin: http://%s\x0d\x0a",
 885                              lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN));
 886
 887         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))
 888                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 889                      lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));
 890
 891         /* tell the server what extensions we could support */
 892
 893         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 894 #ifndef LWS_NO_EXTENSIONS
 895         ext = context->extensions;
 896         while (ext && ext->callback) {
 897
 898                 n = lws_ext_callback_for_each_extension_type(context, wsi,
 899                            LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 900                                                           (char *)ext->name, 0);
 901                 if (n) { /* an extension vetos us */
 902                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 903                         ext++;
 904                         continue;
 905                 }
 906
 907                 n = context->protocols[0].callback(context, wsi,
 908                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 909                                 wsi->user_space, (char *)ext->name, 0);
 910
 911                 /*
 912                  * zero return from callback means
 913                  * go ahead and allow the extension,
 914                  * it's what we get if the callback is
 915                  * unhandled
 916                  */
 917
 918                 if (n) {
 919                         ext++;
 920                         continue;
 921                 }
 922
 923                 /* apply it */
 924
 925                 if (ext_count)
 926                         *p++ = ',';
 927                 p += sprintf(p, "%s", ext->name);
 928                 ext_count++;
 929
 930                 ext++;
 931         }
 932 #endif
 933         p += sprintf(p, "\x0d\x0a");
 934
 935         if (wsi->ietf_spec_revision)
 936                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 937                                                wsi->ietf_spec_revision);
 938
 939         /* give userland a chance to append, eg, cookies */
 940
 941         context->protocols[0].callback(context, wsi,
 942                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 943                 NULL, &p, (pkt + sizeof(context->service_buffer)) - p - 12);
 944
 945         p += sprintf(p, "\x0d\x0a");
 946
 947         /* prepare the expected server accept response */
 948
 949         key_b64[39] = '\0'; /* enforce composed length below buf sizeof */
 950         n = sprintf(buf, "%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", key_b64);
 951
 952         libwebsockets_SHA1((unsigned char *)buf, n, (unsigned char *)hash);
 953
 954         lws_b64_encode_string(hash, 20,
 955                         wsi->u.hdr.ah->initial_handshake_hash_base64,
 956                           sizeof(wsi->u.hdr.ah->initial_handshake_hash_base64));
 957
 958         return p;
 959 }
 960