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 (lws_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, (char *)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                     strcmp((char *)context->service_buffer, "HTTP/1.1 200 ")
 105                 ) {
 106                         libwebsocket_close_and_free_session(context, wsi,
 107                                                      LWS_CLOSE_STATUS_NOSTATUS);
 108                         lwsl_err("ERROR proxy: %s\n", context->service_buffer);
 109                         return 0;
 110                 }
 111
 112                 /* clear his proxy connection timeout */
 113
 114                 lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 115
 116                 /* fallthru */
 117
 118         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
 119
 120                 /*
 121                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
 122                  * timeout protection set in client-handshake.c
 123                  */
 124
 125                 /*
 126                  * take care of our lws_callback_on_writable
 127                  * happening at a time when there's no real connection yet
 128                  */
 129                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0))
 130                         return -1;
 131                 lws_libev_io(context, wsi, LWS_EV_STOP | LWS_EV_WRITE);
 132
 133 #ifdef LWS_OPENSSL_SUPPORT
 134                 /* we can retry this... just cook the SSL BIO the first time */
 135
 136                 if (wsi->use_ssl && !wsi->ssl) {
 137 #if defined(CYASSL_SNI_HOST_NAME) || defined(WOLFSSL_SNI_HOST_NAME) || defined(SSL_CTRL_SET_TLSEXT_HOSTNAME)
 138                         const char *hostname = lws_hdr_simple_ptr(wsi,
 139                                                 _WSI_TOKEN_CLIENT_HOST);
 140 #endif
 141
 142                         wsi->ssl = SSL_new(context->ssl_client_ctx);
 143 #ifndef USE_WOLFSSL
 144                         SSL_set_mode(wsi->ssl,
 145                                         SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
 146 #endif
 147                         /*
 148                          * use server name indication (SNI), if supported,
 149                          * when establishing connection
 150                          */
 151 #ifdef USE_WOLFSSL
 152 #ifdef USE_OLD_CYASSL
 153 #ifdef CYASSL_SNI_HOST_NAME
 154                         CyaSSL_UseSNI(wsi->ssl, CYASSL_SNI_HOST_NAME,
 155                                 hostname, strlen(hostname));
 156 #endif
 157 #else
 158 #ifdef WOLFSSL_SNI_HOST_NAME
 159                         wolfSSL_UseSNI(wsi->ssl, WOLFSSL_SNI_HOST_NAME,
 160                                 hostname, strlen(hostname));
 161 #endif
 162 #endif
 163 #else
 164 #ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
 165                         SSL_set_tlsext_host_name(wsi->ssl, hostname);
 166 #endif
 167 #endif
 168
 169 #ifdef USE_WOLFSSL
 170                         /*
 171                          * wolfSSL/CyaSSL does certificate verification differently
 172                          * from OpenSSL.
 173                          * If we should ignore the certificate, we need to set
 174                          * this before SSL_new and SSL_connect is called.
 175                          * Otherwise the connect will simply fail with error
 176                          * code -155
 177                          */
 178 #ifdef USE_OLD_CYASSL
 179                         if (wsi->use_ssl == 2)
 180                                 CyaSSL_set_verify(wsi->ssl,
 181                                                         SSL_VERIFY_NONE, NULL);
 182 #else
 183                         if (wsi->use_ssl == 2)
 184                                 wolfSSL_set_verify(wsi->ssl,
 185                                                         SSL_VERIFY_NONE, NULL);
 186 #endif
 187 #endif /* USE_WOLFSSL */
 188
 189                         wsi->client_bio =
 190                                 BIO_new_socket(wsi->sock, BIO_NOCLOSE);
 191                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 192
 193 #ifdef USE_WOLFSSL
 194 #ifdef USE_OLD_CYASSL
 195                         CyaSSL_set_using_nonblock(wsi->ssl, 1);
 196 #else
 197                         wolfSSL_set_using_nonblock(wsi->ssl, 1);
 198 #endif
 199 #else
 200                         BIO_set_nbio(wsi->client_bio, 1); /* nonblocking */
 201 #endif
 202
 203                         SSL_set_ex_data(wsi->ssl,
 204                                         openssl_websocket_private_data_index,
 205                                                                        context);
 206                 }
 207
 208                 if (wsi->use_ssl) {
 209                         lws_latency_pre(context, wsi);
 210                         n = SSL_connect(wsi->ssl);
 211                         lws_latency(context, wsi,
 212                           "SSL_connect LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE",
 213                                                                       n, n > 0);
 214
 215                         if (n < 0) {
 216                                 n = SSL_get_error(wsi->ssl, n);
 217
 218                                 if (n == SSL_ERROR_WANT_READ)
 219                                         goto some_wait;
 220
 221                                 if (n == SSL_ERROR_WANT_WRITE) {
 222                                         /*
 223                                          * wants us to retry connect due to
 224                                          * state of the underlying ssl layer...
 225                                          * but since it may be stalled on
 226                                          * blocked write, no incoming data may
 227                                          * arrive to trigger the retry.
 228                                          * Force (possibly many times if the SSL
 229                                          * state persists in returning the
 230                                          * condition code, but other sockets
 231                                          * are getting serviced inbetweentimes)
 232                                          * us to get called back when writable.
 233                                          */
 234
 235                                         lwsl_info(
 236                                              "SSL_connect WANT_WRITE... retrying\n");
 237                                         lws_callback_on_writable(
 238                                                                   context, wsi);
 239 some_wait:
 240                                         wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SSL;
 241
 242                                         return 0; /* no error */
 243                                 }
 244                                 n = -1;
 245                         }
 246
 247                         if (n <= 0) {
 248                                 /*
 249                                  * retry if new data comes until we
 250                                  * run into the connection timeout or win
 251                                  */
 252
 253                                 n = ERR_get_error();
 254                                 if (n != SSL_ERROR_NONE) {
 255                                         lwsl_err("SSL connect error %lu: %s\n",
 256                                                 n,
 257                                                 ERR_error_string(n,
 258                                                           (char *)context->service_buffer));
 259                                         return 0;
 260                                 }
 261                         }
 262                 } else
 263                         wsi->ssl = NULL;
 264
 265                 /* fallthru */
 266
 267         case LWS_CONNMODE_WS_CLIENT_WAITING_SSL:
 268
 269                 if (wsi->use_ssl) {
 270
 271                         if (wsi->mode == LWS_CONNMODE_WS_CLIENT_WAITING_SSL) {
 272                                 lws_latency_pre(context, wsi);
 273                                 n = SSL_connect(wsi->ssl);
 274                                 lws_latency(context, wsi,
 275                                             "SSL_connect LWS_CONNMODE_WS_CLIENT_WAITING_SSL",
 276                                             n, n > 0);
 277
 278                                 if (n < 0) {
 279                                         n = SSL_get_error(wsi->ssl, n);
 280
 281                                         if (n == SSL_ERROR_WANT_READ)
 282                                                 goto some_wait;
 283
 284                                         if (n == SSL_ERROR_WANT_WRITE) {
 285                                                 /*
 286                                                  * wants us to retry connect due to
 287                                                  * state of the underlying ssl layer...
 288                                                  * but since it may be stalled on
 289                                                  * blocked write, no incoming data may
 290                                                  * arrive to trigger the retry.
 291                                                  * Force (possibly many times if the SSL
 292                                                  * state persists in returning the
 293                                                  * condition code, but other sockets
 294                                                  * are getting serviced inbetweentimes)
 295                                                  * us to get called back when writable.
 296                                                  */
 297
 298                                                 lwsl_info("SSL_connect WANT_WRITE... retrying\n");
 299                                                 lws_callback_on_writable(context, wsi);
 300
 301                                                 goto some_wait;
 302                                         }
 303                                         n = -1;
 304                                 }
 305
 306                                 if (n <= 0) {
 307                                         /*
 308                                          * retry if new data comes until we
 309                                          * run into the connection timeout or win
 310                                          */
 311                                         n = ERR_get_error();
 312                                         if (n != SSL_ERROR_NONE) {
 313                                                 lwsl_err("SSL connect error %lu: %s\n",
 314                                                          n, ERR_error_string(n,
 315                                                          (char *)context->service_buffer));
 316                                                 return 0;
 317                                         }
 318                                 }
 319                         }
 320
 321                         #ifndef USE_WOLFSSL
 322                         /*
 323                          * See comment above about wolfSSL certificate
 324                          * verification
 325                          */
 326                         lws_latency_pre(context, wsi);
 327                         n = SSL_get_verify_result(wsi->ssl);
 328                         lws_latency(context, wsi,
 329                                 "SSL_get_verify_result LWS_CONNMODE..HANDSHAKE",
 330                                                                       n, n > 0);
 331
 332                         if (n != X509_V_OK) {
 333                                 if ((n == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 334                                      n == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN) && wsi->use_ssl == 2) {
 335                                         lwsl_notice("accepting self-signed certificate\n");
 336                                 } else {
 337                                         lwsl_err("server's cert didn't look good, X509_V_ERR = %d: %s\n",
 338                                                  n, ERR_error_string(n, (char *)context->service_buffer));
 339                                         libwebsocket_close_and_free_session(context,
 340                                                         wsi, LWS_CLOSE_STATUS_NOSTATUS);
 341                                         return 0;
 342                                 }
 343                         }
 344 #endif /* USE_WOLFSSL */
 345                 } else
 346                         wsi->ssl = NULL;
 347 #endif
 348
 349                 wsi->mode = LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2;
 350                 lws_set_timeout(wsi,
 351                                 PENDING_TIMEOUT_AWAITING_CLIENT_HS_SEND,
 352                                                               AWAITING_TIMEOUT);
 353
 354                 /* fallthru */
 355
 356         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2:
 357                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 358                 if (p == NULL) {
 359                         lwsl_err("Failed to generate handshake for client\n");
 360                         libwebsocket_close_and_free_session(context, wsi,
 361                                                      LWS_CLOSE_STATUS_NOSTATUS);
 362                         return 0;
 363                 }
 364
 365                 /* send our request to the server */
 366
 367                 lws_latency_pre(context, wsi);
 368
 369                 n = lws_ssl_capable_write(wsi, context->service_buffer, p - (char *)context->service_buffer);
 370                 lws_latency(context, wsi, "send lws_issue_raw", n, n == p - (char *)context->service_buffer);
 371                 switch (n) {
 372                 case LWS_SSL_CAPABLE_ERROR:
 373                         lwsl_debug("ERROR writing to client socket\n");
 374                         libwebsocket_close_and_free_session(context, wsi,
 375                                                      LWS_CLOSE_STATUS_NOSTATUS);
 376                         return 0;
 377                 case LWS_SSL_CAPABLE_MORE_SERVICE:
 378                         lws_callback_on_writable(context, wsi);
 379                         break;
 380                 }
 381
 382                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 383                 wsi->u.hdr.lextable_pos = 0;
 384                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 385                 lws_set_timeout(wsi,
 386                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE,
 387                                                               AWAITING_TIMEOUT);
 388                 break;
 389
 390         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 391
 392                 /* handle server hung up on us */
 393
 394                 if (pollfd->revents & LWS_POLLHUP) {
 395
 396                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 397                                 (void *)wsi, pollfd->fd);
 398
 399                         goto bail3;
 400                 }
 401
 402                 if (!(pollfd->revents & LWS_POLLIN))
 403                         break;
 404
 405                 /* interpret the server response */
 406
 407                 /*
 408                  *  HTTP/1.1 101 Switching Protocols
 409                  *  Upgrade: websocket
 410                  *  Connection: Upgrade
 411                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 412                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 413                  *  Sec-WebSocket-Protocol: chat
 414                  */
 415
 416                 /*
 417                  * we have to take some care here to only take from the
 418                  * socket bytewise.  The browser may (and has been seen to
 419                  * in the case that onopen() performs websocket traffic)
 420                  * coalesce both handshake response and websocket traffic
 421                  * in one packet, since at that point the connection is
 422                  * definitively ready from browser pov.
 423                  */
 424                 len = 1;
 425                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE &&
 426                                                                       len > 0) {
 427                         n = lws_ssl_capable_read(context, wsi, &c, 1);
 428                         lws_latency(context, wsi, "send lws_issue_raw", n, n == 1);
 429                         switch (n) {
 430                         case LWS_SSL_CAPABLE_ERROR:
 431                                 goto bail3;
 432                         case LWS_SSL_CAPABLE_MORE_SERVICE:
 433                                 return 0;
 434                         }
 435
 436                         if (libwebsocket_parse(context, wsi, c)) {
 437                                 lwsl_warn("problems parsing header\n");
 438                                 goto bail3;
 439                         }
 440                 }
 441
 442                 /*
 443                  * hs may also be coming in multiple packets, there is a 5-sec
 444                  * libwebsocket timeout still active here too, so if parsing did
 445                  * not complete just wait for next packet coming in this state
 446                  */
 447
 448                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 449                         break;
 450
 451                 /*
 452                  * otherwise deal with the handshake.  If there's any
 453                  * packet traffic already arrived we'll trigger poll() again
 454                  * right away and deal with it that way
 455                  */
 456
 457                 return lws_client_interpret_server_handshake(context, wsi);
 458
 459 bail3:
 460                 lwsl_info(
 461                         "closing connection at LWS_CONNMODE...SERVER_REPLY\n");
 462                 libwebsocket_close_and_free_session(context, wsi,
 463                                                     LWS_CLOSE_STATUS_NOSTATUS);
 464                 return -1;
 465
 466         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 467                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 468                 break;
 469
 470         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 471                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 472                 break;
 473         default:
 474                 break;
 475         }
 476
 477         return 0;
 478 }
 479
 480
 481 /*
 482  * In-place str to lower case
 483  */
 484
 485 static void
 486 strtolower(char *s)
 487 {
 488         while (*s) {
 489                 *s = tolower((int)*s);
 490                 s++;
 491         }
 492 }
 493
 494 int
 495 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 496                 struct libwebsocket *wsi)
 497 {
 498         const char *pc;
 499         int okay = 0;
 500         char *p;
 501         int len;
 502         int isErrorCodeReceived = 0;
 503 #ifndef LWS_NO_EXTENSIONS
 504         char ext_name[128];
 505         struct libwebsocket_extension *ext;
 506         void *v;
 507         int more = 1;
 508         const char *c;
 509 #endif
 510         int n;
 511         int close_reason = LWS_CLOSE_STATUS_PROTOCOL_ERR;
 512
 513         /*
 514          * well, what the server sent looked reasonable for syntax.
 515          * Now let's confirm it sent all the necessary headers
 516          */
 517
 518         if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0) {
 519                 lwsl_info("no ACCEPT\n");
 520                 p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 521                 isErrorCodeReceived = 1;
 522                 goto bail3;
 523         }
 524
 525         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 526         if (!p) {
 527                 lwsl_info("no URI\n");
 528                 goto bail3;
 529         }
 530         if (p && strncmp(p, "101", 3)) {
 531                 lwsl_warn(
 532                        "lws_client_handshake: got bad HTTP response '%s'\n", p);
 533                 goto bail3;
 534         }
 535
 536         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
 537         if (!p) {
 538                 lwsl_info("no UPGRADE\n");
 539                 goto bail3;
 540         }
 541         strtolower(p);
 542         if (strcmp(p, "websocket")) {
 543                 lwsl_warn(
 544                       "lws_client_handshake: got bad Upgrade header '%s'\n", p);
 545                 goto bail3;
 546         }
 547
 548         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
 549         if (!p) {
 550                 lwsl_info("no Connection hdr\n");
 551                 goto bail3;
 552         }
 553         strtolower(p);
 554         if (strcmp(p, "upgrade")) {
 555                 lwsl_warn("lws_client_int_s_hs: bad header %s\n", p);
 556                 goto bail3;
 557         }
 558
 559         pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);
 560         if (pc == NULL) {
 561                 lwsl_parser("lws_client_int_s_hs: no protocol list\n");
 562         } else
 563                 lwsl_parser("lws_client_int_s_hs: protocol list '%s'\n", pc);
 564
 565         /*
 566          * confirm the protocol the server wants to talk was in the list
 567          * of protocols we offered
 568          */
 569
 570         len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
 571         if (!len) {
 572
 573                 lwsl_info("lws_client_int_s_hs: WSI_TOKEN_PROTOCOL is null\n");
 574                 /*
 575                  * no protocol name to work from,
 576                  * default to first protocol
 577                  */
 578                 wsi->protocol = &context->protocols[0];
 579                 goto check_extensions;
 580         }
 581
 582         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
 583         len = strlen(p);
 584
 585         while (pc && *pc && !okay) {
 586                 if (!strncmp(pc, p, len) &&
 587                     (pc[len] == ',' || pc[len] == '\0')) {
 588                         okay = 1;
 589                         continue;
 590                 }
 591                 while (*pc && *pc++ != ',')
 592                         ;
 593                 while (*pc && *pc == ' ')
 594                         pc++;
 595         }
 596
 597         if (!okay) {
 598                 lwsl_err("lws_client_int_s_hs: got bad protocol %s\n", p);
 599                 goto bail2;
 600         }
 601
 602         /*
 603          * identify the selected protocol struct and set it
 604          */
 605         n = 0;
 606         wsi->protocol = NULL;
 607         while (context->protocols[n].callback && !wsi->protocol) {
 608                 if (strcmp(p, context->protocols[n].name) == 0) {
 609                         wsi->protocol = &context->protocols[n];
 610                         break;
 611                 }
 612                 n++;
 613         }
 614
 615         if (wsi->protocol == NULL) {
 616                 lwsl_err("lws_client_int_s_hs: fail protocol %s\n", p);
 617                 goto bail2;
 618         }
 619
 620
 621 check_extensions:
 622 #ifndef LWS_NO_EXTENSIONS
 623         /* instantiate the accepted extensions */
 624
 625         if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
 626                 lwsl_ext("no client extenstions allowed by server\n");
 627                 goto check_accept;
 628         }
 629
 630         /*
 631          * break down the list of server accepted extensions
 632          * and go through matching them or identifying bogons
 633          */
 634
 635         if (lws_hdr_copy(wsi, (char *)context->service_buffer,
 636                    sizeof(context->service_buffer), WSI_TOKEN_EXTENSIONS) < 0) {
 637                 lwsl_warn("ext list from server failed to copy\n");
 638                 goto bail2;
 639         }
 640
 641         c = (char *)context->service_buffer;
 642         n = 0;
 643         while (more) {
 644
 645                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 646                         ext_name[n] = *c++;
 647                         if (n < sizeof(ext_name) - 1)
 648                                 n++;
 649                         continue;
 650                 }
 651                 ext_name[n] = '\0';
 652                 if (!*c)
 653                         more = 0;
 654                 else {
 655                         c++;
 656                         if (!n)
 657                                 continue;
 658                 }
 659
 660                 /* check we actually support it */
 661
 662                 lwsl_ext("checking client ext %s\n", ext_name);
 663
 664                 n = 0;
 665                 ext = wsi->protocol->owning_server->extensions;
 666                 while (ext && ext->callback) {
 667
 668                         if (strcmp(ext_name, ext->name)) {
 669                                 ext++;
 670                                 continue;
 671                         }
 672
 673                         n = 1;
 674
 675                         lwsl_ext("instantiating client ext %s\n", ext_name);
 676
 677                         /* instantiate the extension on this conn */
 678
 679                         wsi->active_extensions_user[
 680                                 wsi->count_active_extensions] =
 681                                          lws_zalloc(ext->per_session_data_size);
 682                         if (wsi->active_extensions_user[
 683                                 wsi->count_active_extensions] == NULL) {
 684                                 lwsl_err("Out of mem\n");
 685                                 goto bail2;
 686                         }
 687                         wsi->active_extensions[
 688                                   wsi->count_active_extensions] = ext;
 689
 690                         /* allow him to construct his context */
 691
 692                         ext->callback(wsi->protocol->owning_server,
 693                                 ext, wsi,
 694                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 695                                         wsi->active_extensions_user[
 696                                          wsi->count_active_extensions],
 697                                                                    NULL, 0);
 698
 699                         wsi->count_active_extensions++;
 700
 701                         ext++;
 702                 }
 703
 704                 if (n == 0) {
 705                         lwsl_warn("Unknown ext '%s'!\n", ext_name);
 706                         goto bail2;
 707                 }
 708
 709                 n = 0;
 710         }
 711
 712 check_accept:
 713 #endif
 714
 715         /*
 716          * Confirm his accept token is the one we precomputed
 717          */
 718
 719         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
 720         if (strcmp(p, wsi->u.hdr.ah->initial_handshake_hash_base64)) {
 721                 lwsl_warn("lws_client_int_s_hs: accept %s wrong vs %s\n", p,
 722                                   wsi->u.hdr.ah->initial_handshake_hash_base64);
 723                 goto bail2;
 724         }
 725
 726         /* allocate the per-connection user memory (if any) */
 727         if (libwebsocket_ensure_user_space(wsi)) {
 728                 lwsl_err("Problem allocating wsi user mem\n");
 729                 goto bail2;
 730         }
 731
 732         /*
 733          * we seem to be good to go, give client last chance to check
 734          * headers and OK it
 735          */
 736
 737         wsi->protocol->callback(context, wsi,
 738                                 LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
 739                                                      wsi->user_space, NULL, 0);
 740
 741         /* clear his proxy connection timeout */
 742
 743         lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 744
 745         /* free up his parsing allocations */
 746
 747         lws_free(wsi->u.hdr.ah);
 748
 749         lws_union_transition(wsi, LWS_CONNMODE_WS_CLIENT);
 750         wsi->state = WSI_STATE_ESTABLISHED;
 751
 752         wsi->rxflow_change_to = LWS_RXFLOW_ALLOW;
 753
 754         /*
 755          * create the frame buffer for this connection according to the
 756          * size mentioned in the protocol definition.  If 0 there, then
 757          * use a big default for compatibility
 758          */
 759
 760         n = wsi->protocol->rx_buffer_size;
 761         if (!n)
 762                 n = LWS_MAX_SOCKET_IO_BUF;
 763         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 764         wsi->u.ws.rx_user_buffer = lws_malloc(n);
 765         if (!wsi->u.ws.rx_user_buffer) {
 766                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 767                 goto bail2;
 768         }
 769         lwsl_info("Allocating client RX buffer %d\n", n);
 770
 771         if (setsockopt(wsi->sock, SOL_SOCKET, SO_SNDBUF, (const char *)&n, sizeof n)) {
 772                 lwsl_warn("Failed to set SNDBUF to %d", n);
 773                 goto bail3;
 774         }
 775
 776         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 777
 778         /* call him back to inform him he is up */
 779
 780         wsi->protocol->callback(context, wsi,
 781                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 782                                                      wsi->user_space, NULL, 0);
 783 #ifndef LWS_NO_EXTENSIONS
 784         /*
 785          * inform all extensions, not just active ones since they
 786          * already know
 787          */
 788
 789         ext = context->extensions;
 790
 791         while (ext && ext->callback) {
 792                 v = NULL;
 793                 for (n = 0; n < wsi->count_active_extensions; n++)
 794                         if (wsi->active_extensions[n] == ext)
 795                                 v = wsi->active_extensions_user[n];
 796
 797                 ext->callback(context, ext, wsi,
 798                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 799                 ext++;
 800         }
 801 #endif
 802
 803         return 0;
 804
 805 bail3:
 806         lws_free2(wsi->u.ws.rx_user_buffer);
 807         close_reason = LWS_CLOSE_STATUS_NOSTATUS;
 808
 809 bail2:
 810         if (wsi->protocol) {
 811                 if (isErrorCodeReceived && p) {
 812                         wsi->protocol->callback(context, wsi,
 813                                 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 814                                         wsi->user_space, p, (unsigned int)strlen(p));
 815                 } else {
 816                         wsi->protocol->callback(context, wsi,
 817                                 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 818                                                               wsi->user_space, NULL, 0);
 819                 }
 820         }
 821
 822         lwsl_info("closing connection due to bail2 connection error\n");
 823
 824         /* free up his parsing allocations */
 825
 826         lws_free2(wsi->u.hdr.ah);
 827
 828         libwebsocket_close_and_free_session(context, wsi, close_reason);
 829
 830         return 1;
 831 }
 832
 833
 834 char *
 835 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 836                 struct libwebsocket *wsi, char *pkt)
 837 {
 838         char buf[128];
 839         char hash[20];
 840         char key_b64[40];
 841         char *p = pkt;
 842         int n;
 843 #ifndef LWS_NO_EXTENSIONS
 844         struct libwebsocket_extension *ext;
 845         int ext_count = 0;
 846 #endif
 847
 848         /*
 849          * create the random key
 850          */
 851
 852         n = lws_get_random(context, hash, 16);
 853         if (n != 16) {
 854                 lwsl_err("Unable to read from random dev %s\n",
 855                                                 SYSTEM_RANDOM_FILEPATH);
 856                 libwebsocket_close_and_free_session(context, wsi,
 857                                              LWS_CLOSE_STATUS_NOSTATUS);
 858                 return NULL;
 859         }
 860
 861         lws_b64_encode_string(hash, 16, key_b64, sizeof(key_b64));
 862
 863         /*
 864          * 00 example client handshake
 865          *
 866          * GET /socket.io/websocket HTTP/1.1
 867          * Upgrade: WebSocket
 868          * Connection: Upgrade
 869          * Host: 127.0.0.1:9999
 870          * Origin: http://127.0.0.1
 871          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 872          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 873          * Cookie: socketio=websocket
 874          *
 875          * (Á®Ä0¶†≥
 876          *
 877          * 04 example client handshake
 878          *
 879          * GET /chat HTTP/1.1
 880          * Host: server.example.com
 881          * Upgrade: websocket
 882          * Connection: Upgrade
 883          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 884          * Sec-WebSocket-Origin: http://example.com
 885          * Sec-WebSocket-Protocol: chat, superchat
 886          * Sec-WebSocket-Version: 4
 887          */
 888
 889         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a",
 890                                 lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_URI));
 891
 892         p += sprintf(p,
 893                 "Pragma: no-cache\x0d\x0a""Cache-Control: no-cache\x0d\x0a");
 894
 895         p += sprintf(p, "Host: %s\x0d\x0a",
 896                                lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_HOST));
 897         p += sprintf(p,
 898 "Upgrade: websocket\x0d\x0a""Connection: Upgrade\x0d\x0a""Sec-WebSocket-Key: ");
 899         strcpy(p, key_b64);
 900         p += strlen(key_b64);
 901         p += sprintf(p, "\x0d\x0a");
 902         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN))
 903                 p += sprintf(p, "Origin: http://%s\x0d\x0a",
 904                              lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN));
 905
 906         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))
 907                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 908                      lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));
 909
 910         /* tell the server what extensions we could support */
 911
 912         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 913 #ifndef LWS_NO_EXTENSIONS
 914         ext = context->extensions;
 915         while (ext && ext->callback) {
 916
 917                 n = lws_ext_callback_for_each_extension_type(context, wsi,
 918                            LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 919                                                           (char *)ext->name, 0);
 920                 if (n) { /* an extension vetos us */
 921                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 922                         ext++;
 923                         continue;
 924                 }
 925
 926                 n = context->protocols[0].callback(context, wsi,
 927                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 928                                 wsi->user_space, (char *)ext->name, 0);
 929
 930                 /*
 931                  * zero return from callback means
 932                  * go ahead and allow the extension,
 933                  * it's what we get if the callback is
 934                  * unhandled
 935                  */
 936
 937                 if (n) {
 938                         ext++;
 939                         continue;
 940                 }
 941
 942                 /* apply it */
 943
 944                 if (ext_count)
 945                         *p++ = ',';
 946                 p += sprintf(p, "%s", ext->name);
 947                 ext_count++;
 948
 949                 ext++;
 950         }
 951 #endif
 952         p += sprintf(p, "\x0d\x0a");
 953
 954         if (wsi->ietf_spec_revision)
 955                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 956                                                wsi->ietf_spec_revision);
 957
 958         /* give userland a chance to append, eg, cookies */
 959
 960         context->protocols[0].callback(context, wsi,
 961                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 962                 NULL, &p, (pkt + sizeof(context->service_buffer)) - p - 12);
 963
 964         p += sprintf(p, "\x0d\x0a");
 965
 966         /* prepare the expected server accept response */
 967
 968         key_b64[39] = '\0'; /* enforce composed length below buf sizeof */
 969         n = sprintf(buf, "%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", key_b64);
 970
 971         lws_SHA1((unsigned char *)buf, n, (unsigned char *)hash);
 972
 973         lws_b64_encode_string(hash, 20,
 974                         wsi->u.hdr.ah->initial_handshake_hash_base64,
 975                           sizeof(wsi->u.hdr.ah->initial_handshake_hash_base64));
 976
 977         return p;
 978 }
 979