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                         if ((n != X509_V_OK) && (
 313                                 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 314                                                            wsi->use_ssl != 2)) {
 315
 316                                 lwsl_err(
 317                                       "server's cert didn't look good %d\n", n);
 318                                 libwebsocket_close_and_free_session(context,
 319                                                 wsi, LWS_CLOSE_STATUS_NOSTATUS);
 320                                 return 0;
 321                         }
 322 #endif /* USE_CYASSL */
 323                 } else
 324                         wsi->ssl = NULL;
 325 #endif
 326
 327                 wsi->mode = LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2;
 328                 libwebsocket_set_timeout(wsi,
 329                                 PENDING_TIMEOUT_AWAITING_CLIENT_HS_SEND,
 330                                                               AWAITING_TIMEOUT);
 331
 332                 /* fallthru */
 333
 334         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE2:
 335                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 336                 if (p == NULL) {
 337                         lwsl_err("Failed to generate handshake for client\n");
 338                         libwebsocket_close_and_free_session(context, wsi,
 339                                                      LWS_CLOSE_STATUS_NOSTATUS);
 340                         return 0;
 341                 }
 342
 343                 /* send our request to the server */
 344
 345                 lws_latency_pre(context, wsi);
 346
 347                 n = lws_ssl_capable_write(wsi, context->service_buffer, p - (char *)context->service_buffer);
 348                 lws_latency(context, wsi, "send lws_issue_raw", n, n == p - (char *)context->service_buffer);
 349                 switch (n) {
 350                 case LWS_SSL_CAPABLE_ERROR:
 351                         lwsl_debug("ERROR writing to client socket\n");
 352                         libwebsocket_close_and_free_session(context, wsi,
 353                                                      LWS_CLOSE_STATUS_NOSTATUS);
 354                         return 0;
 355                 case LWS_SSL_CAPABLE_MORE_SERVICE:
 356                         libwebsocket_callback_on_writable(context, wsi);
 357                         break;
 358                 }
 359
 360                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 361                 wsi->u.hdr.lextable_pos = 0;
 362                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 363                 libwebsocket_set_timeout(wsi,
 364                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE,
 365                                                               AWAITING_TIMEOUT);
 366                 break;
 367
 368         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 369
 370                 /* handle server hung up on us */
 371
 372                 if (pollfd->revents & LWS_POLLHUP) {
 373
 374                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 375                                 (void *)wsi, pollfd->fd);
 376
 377                         goto bail3;
 378                 }
 379
 380                 if (!(pollfd->revents & LWS_POLLIN))
 381                         break;
 382
 383                 /* interpret the server response */
 384
 385                 /*
 386                  *  HTTP/1.1 101 Switching Protocols
 387                  *  Upgrade: websocket
 388                  *  Connection: Upgrade
 389                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 390                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 391                  *  Sec-WebSocket-Protocol: chat
 392                  */
 393
 394                 /*
 395                  * we have to take some care here to only take from the
 396                  * socket bytewise.  The browser may (and has been seen to
 397                  * in the case that onopen() performs websocket traffic)
 398                  * coalesce both handshake response and websocket traffic
 399                  * in one packet, since at that point the connection is
 400                  * definitively ready from browser pov.
 401                  */
 402                 len = 1;
 403                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE &&
 404                                                                       len > 0) {
 405                         n = lws_ssl_capable_read(wsi, &c, 1);
 406                         lws_latency(context, wsi, "send lws_issue_raw", n, n == 1);
 407                         switch (n) {
 408                         case LWS_SSL_CAPABLE_ERROR:
 409                                 goto bail3;
 410                         case LWS_SSL_CAPABLE_MORE_SERVICE:
 411                                 return 0;
 412                         }
 413
 414                         if (libwebsocket_parse(wsi, c)) {
 415                                 lwsl_warn("problems parsing header\n");
 416                                 goto bail3;
 417                         }
 418                 }
 419
 420                 /*
 421                  * hs may also be coming in multiple packets, there is a 5-sec
 422                  * libwebsocket timeout still active here too, so if parsing did
 423                  * not complete just wait for next packet coming in this state
 424                  */
 425
 426                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 427                         break;
 428
 429                 /*
 430                  * otherwise deal with the handshake.  If there's any
 431                  * packet traffic already arrived we'll trigger poll() again
 432                  * right away and deal with it that way
 433                  */
 434
 435                 return lws_client_interpret_server_handshake(context, wsi);
 436
 437 bail3:
 438                 lwsl_info(
 439                         "closing connection at LWS_CONNMODE...SERVER_REPLY\n");
 440                 libwebsocket_close_and_free_session(context, wsi,
 441                                                     LWS_CLOSE_STATUS_NOSTATUS);
 442                 return -1;
 443
 444         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 445                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 446                 break;
 447
 448         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 449                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 450                 break;
 451         default:
 452                 break;
 453         }
 454
 455         return 0;
 456 }
 457
 458
 459 /*
 460  * In-place str to lower case
 461  */
 462
 463 static void
 464 strtolower(char *s)
 465 {
 466         while (*s) {
 467                 *s = tolower((int)*s);
 468                 s++;
 469         }
 470 }
 471
 472 int
 473 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 474                 struct libwebsocket *wsi)
 475 {
 476         const char *pc;
 477         int okay = 0;
 478         char *p;
 479         int len;
 480 #ifndef LWS_NO_EXTENSIONS
 481         char ext_name[128];
 482         struct libwebsocket_extension *ext;
 483         void *v;
 484         int more = 1;
 485         const char *c;
 486 #endif
 487         int n;
 488         int close_reason = LWS_CLOSE_STATUS_PROTOCOL_ERR;
 489
 490         /*
 491          * well, what the server sent looked reasonable for syntax.
 492          * Now let's confirm it sent all the necessary headers
 493          */
 494
 495         if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0) {
 496                 lwsl_info("no ACCEPT\n");
 497                 goto bail3;
 498         }
 499
 500         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 501         if (!p) {
 502                 lwsl_info("no URI\n");
 503                 goto bail3;
 504         }
 505         if (p && strncmp(p, "101", 3)) {
 506                 lwsl_warn(
 507                        "lws_client_handshake: got bad HTTP response '%s'\n", p);
 508                 goto bail3;
 509         }
 510
 511         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
 512         if (!p) {
 513                 lwsl_info("no UPGRADE\n");
 514                 goto bail3;
 515         }
 516         strtolower(p);
 517         if (strcmp(p, "websocket")) {
 518                 lwsl_warn(
 519                       "lws_client_handshake: got bad Upgrade header '%s'\n", p);
 520                 goto bail3;
 521         }
 522
 523         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
 524         if (!p) {
 525                 lwsl_info("no Connection hdr\n");
 526                 goto bail3;
 527         }
 528         strtolower(p);
 529         if (strcmp(p, "upgrade")) {
 530                 lwsl_warn("lws_client_int_s_hs: bad header %s\n", p);
 531                 goto bail3;
 532         }
 533
 534         pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);
 535         if (pc == NULL)
 536                 lwsl_parser("lws_client_int_s_hs: no protocol list\n");
 537         else
 538                 lwsl_parser("lws_client_int_s_hs: protocol list '%s'\n", pc);
 539
 540         /*
 541          * confirm the protocol the server wants to talk was in the list
 542          * of protocols we offered
 543          */
 544
 545         len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
 546         if (!len) {
 547
 548                 lwsl_info("lws_client_int_s_hs: WSI_TOKEN_PROTOCOL is null\n");
 549                 /*
 550                  * no protocol name to work from,
 551                  * default to first protocol
 552                  */
 553                 wsi->protocol = &context->protocols[0];
 554                 goto check_extensions;
 555         }
 556
 557         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
 558         len = strlen(p);
 559
 560         while (*pc && !okay) {
 561                 if (!strncmp(pc, p, len) &&
 562                                           (pc[len] == ',' || pc[len] == '\0')) {
 563                         okay = 1;
 564                         continue;
 565                 }
 566                 while (*pc && *pc != ',')
 567                         pc++;
 568                 while (*pc && *pc != ' ')
 569                         pc++;
 570         }
 571
 572         if (!okay) {
 573                 lwsl_err("lws_client_int_s_hs: got bad protocol %s\n", p);
 574                 goto bail2;
 575         }
 576
 577         /*
 578          * identify the selected protocol struct and set it
 579          */
 580         n = 0;
 581         wsi->protocol = NULL;
 582         while (context->protocols[n].callback && !wsi->protocol) {
 583                 if (strcmp(p, context->protocols[n].name) == 0) {
 584                         wsi->protocol = &context->protocols[n];
 585                         break;
 586                 }
 587                 n++;
 588         }
 589
 590         if (wsi->protocol == NULL) {
 591                 lwsl_err("lws_client_int_s_hs: fail protocol %s\n", p);
 592                 goto bail2;
 593         }
 594
 595
 596 check_extensions:
 597 #ifndef LWS_NO_EXTENSIONS
 598         /* instantiate the accepted extensions */
 599
 600         if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
 601                 lwsl_ext("no client extenstions allowed by server\n");
 602                 goto check_accept;
 603         }
 604
 605         /*
 606          * break down the list of server accepted extensions
 607          * and go through matching them or identifying bogons
 608          */
 609
 610         if (lws_hdr_copy(wsi, (char *)context->service_buffer,
 611                    sizeof(context->service_buffer), WSI_TOKEN_EXTENSIONS) < 0) {
 612                 lwsl_warn("ext list from server failed to copy\n");
 613                 goto bail2;
 614         }
 615
 616         c = (char *)context->service_buffer;
 617         n = 0;
 618         while (more) {
 619
 620                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 621                         ext_name[n] = *c++;
 622                         if (n < sizeof(ext_name) - 1)
 623                                 n++;
 624                         continue;
 625                 }
 626                 ext_name[n] = '\0';
 627                 if (!*c)
 628                         more = 0;
 629                 else {
 630                         c++;
 631                         if (!n)
 632                                 continue;
 633                 }
 634
 635                 /* check we actually support it */
 636
 637                 lwsl_ext("checking client ext %s\n", ext_name);
 638
 639                 n = 0;
 640                 ext = wsi->protocol->owning_server->extensions;
 641                 while (ext && ext->callback) {
 642
 643                         if (strcmp(ext_name, ext->name)) {
 644                                 ext++;
 645                                 continue;
 646                         }
 647
 648                         n = 1;
 649
 650                         lwsl_ext("instantiating client ext %s\n", ext_name);
 651
 652                         /* instantiate the extension on this conn */
 653
 654                         wsi->active_extensions_user[
 655                                 wsi->count_active_extensions] =
 656                                          malloc(ext->per_session_data_size);
 657                         if (wsi->active_extensions_user[
 658                                 wsi->count_active_extensions] == NULL) {
 659                                 lwsl_err("Out of mem\n");
 660                                 goto bail2;
 661                         }
 662                         memset(wsi->active_extensions_user[
 663                                 wsi->count_active_extensions], 0,
 664                                                     ext->per_session_data_size);
 665                         wsi->active_extensions[
 666                                   wsi->count_active_extensions] = ext;
 667
 668                         /* allow him to construct his context */
 669
 670                         ext->callback(wsi->protocol->owning_server,
 671                                 ext, wsi,
 672                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 673                                         wsi->active_extensions_user[
 674                                          wsi->count_active_extensions],
 675                                                                    NULL, 0);
 676
 677                         wsi->count_active_extensions++;
 678
 679                         ext++;
 680                 }
 681
 682                 if (n == 0) {
 683                         lwsl_warn("Unknown ext '%s'!\n", ext_name);
 684                         goto bail2;
 685                 }
 686
 687                 n = 0;
 688         }
 689
 690 check_accept:
 691 #endif
 692
 693         /*
 694          * Confirm his accept token is the one we precomputed
 695          */
 696
 697         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
 698         if (strcmp(p, wsi->u.hdr.ah->initial_handshake_hash_base64)) {
 699                 lwsl_warn("lws_client_int_s_hs: accept %s wrong vs %s\n", p,
 700                                   wsi->u.hdr.ah->initial_handshake_hash_base64);
 701                 goto bail2;
 702         }
 703
 704         /* allocate the per-connection user memory (if any) */
 705         if (libwebsocket_ensure_user_space(wsi)) {
 706                 lwsl_err("Problem allocating wsi user mem\n");
 707                 goto bail2;
 708         }
 709
 710         /*
 711          * we seem to be good to go, give client last chance to check
 712          * headers and OK it
 713          */
 714
 715         wsi->protocol->callback(context, wsi,
 716                                 LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
 717                                                      wsi->user_space, NULL, 0);
 718
 719         /* clear his proxy connection timeout */
 720
 721         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 722
 723         /* free up his parsing allocations */
 724         if (wsi->u.hdr.ah)
 725                 free(wsi->u.hdr.ah);
 726
 727         /* mark him as being alive */
 728
 729         wsi->state = WSI_STATE_ESTABLISHED;
 730         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 731
 732         /* union transition */
 733
 734         memset(&wsi->u, 0, sizeof(wsi->u));
 735
 736         wsi->u.ws.rxflow_change_to = LWS_RXFLOW_ALLOW;
 737
 738         /*
 739          * create the frame buffer for this connection according to the
 740          * size mentioned in the protocol definition.  If 0 there, then
 741          * use a big default for compatibility
 742          */
 743
 744         n = wsi->protocol->rx_buffer_size;
 745         if (!n)
 746                 n = LWS_MAX_SOCKET_IO_BUF;
 747         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 748         wsi->u.ws.rx_user_buffer = malloc(n);
 749         if (!wsi->u.ws.rx_user_buffer) {
 750                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 751                 goto bail2;
 752         }
 753         lwsl_info("Allocating client RX buffer %d\n", n);
 754
 755         if (setsockopt(wsi->sock, SOL_SOCKET, SO_SNDBUF, (const char *)&n, sizeof n)) {
 756                 lwsl_warn("Failed to set SNDBUF to %d", n);
 757                 goto bail3;
 758         }
 759
 760         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 761
 762         /* call him back to inform him he is up */
 763
 764         wsi->protocol->callback(context, wsi,
 765                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 766                                                      wsi->user_space, NULL, 0);
 767 #ifndef LWS_NO_EXTENSIONS
 768         /*
 769          * inform all extensions, not just active ones since they
 770          * already know
 771          */
 772
 773         ext = context->extensions;
 774
 775         while (ext && ext->callback) {
 776                 v = NULL;
 777                 for (n = 0; n < wsi->count_active_extensions; n++)
 778                         if (wsi->active_extensions[n] == ext)
 779                                 v = wsi->active_extensions_user[n];
 780
 781                 ext->callback(context, ext, wsi,
 782                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 783                 ext++;
 784         }
 785 #endif
 786
 787         return 0;
 788
 789 bail3:
 790         free(wsi->u.ws.rx_user_buffer);
 791         wsi->u.ws.rx_user_buffer = NULL;
 792         close_reason = LWS_CLOSE_STATUS_NOSTATUS;
 793
 794 bail2:
 795         if (wsi->protocol)
 796                 wsi->protocol->callback(context, wsi,
 797                         LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 798                                                       wsi->user_space, NULL, 0);
 799
 800         lwsl_info("closing connection due to bail2 connection error\n");
 801
 802         /* free up his parsing allocations */
 803
 804         if (wsi->u.hdr.ah)
 805                 free(wsi->u.hdr.ah);
 806
 807         libwebsocket_close_and_free_session(context, wsi, close_reason);
 808
 809         return 1;
 810 }
 811
 812
 813 char *
 814 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 815                 struct libwebsocket *wsi, char *pkt)
 816 {
 817         char buf[128];
 818         char hash[20];
 819         char key_b64[40];
 820         char *p = pkt;
 821         int n;
 822 #ifndef LWS_NO_EXTENSIONS
 823         struct libwebsocket_extension *ext;
 824         int ext_count = 0;
 825 #endif
 826
 827         /*
 828          * create the random key
 829          */
 830
 831         n = libwebsockets_get_random(context, hash, 16);
 832         if (n != 16) {
 833                 lwsl_err("Unable to read from random dev %s\n",
 834                                                 SYSTEM_RANDOM_FILEPATH);
 835                 libwebsocket_close_and_free_session(context, wsi,
 836                                              LWS_CLOSE_STATUS_NOSTATUS);
 837                 return NULL;
 838         }
 839
 840         lws_b64_encode_string(hash, 16, key_b64, sizeof(key_b64));
 841
 842         /*
 843          * 00 example client handshake
 844          *
 845          * GET /socket.io/websocket HTTP/1.1
 846          * Upgrade: WebSocket
 847          * Connection: Upgrade
 848          * Host: 127.0.0.1:9999
 849          * Origin: http://127.0.0.1
 850          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 851          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 852          * Cookie: socketio=websocket
 853          *
 854          * (Á®Ä0¶†≥
 855          *
 856          * 04 example client handshake
 857          *
 858          * GET /chat HTTP/1.1
 859          * Host: server.example.com
 860          * Upgrade: websocket
 861          * Connection: Upgrade
 862          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 863          * Sec-WebSocket-Origin: http://example.com
 864          * Sec-WebSocket-Protocol: chat, superchat
 865          * Sec-WebSocket-Version: 4
 866          */
 867
 868         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a",
 869                                 lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_URI));
 870
 871         p += sprintf(p,
 872                 "Pragma: no-cache\x0d\x0a""Cache-Control: no-cache\x0d\x0a");
 873
 874         p += sprintf(p, "Host: %s\x0d\x0a",
 875                                lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_HOST));
 876         p += sprintf(p,
 877 "Upgrade: websocket\x0d\x0a""Connection: Upgrade\x0d\x0a""Sec-WebSocket-Key: ");
 878         strcpy(p, key_b64);
 879         p += strlen(key_b64);
 880         p += sprintf(p, "\x0d\x0a");
 881         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN))
 882                 p += sprintf(p, "Origin: http://%s\x0d\x0a",
 883                              lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN));
 884
 885         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))
 886                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 887                      lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));
 888
 889         /* tell the server what extensions we could support */
 890
 891         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 892 #ifndef LWS_NO_EXTENSIONS
 893         ext = context->extensions;
 894         while (ext && ext->callback) {
 895
 896                 n = lws_ext_callback_for_each_extension_type(context, wsi,
 897                            LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 898                                                           (char *)ext->name, 0);
 899                 if (n) { /* an extension vetos us */
 900                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 901                         ext++;
 902                         continue;
 903                 }
 904
 905                 n = context->protocols[0].callback(context, wsi,
 906                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 907                                 wsi->user_space, (char *)ext->name, 0);
 908
 909                 /*
 910                  * zero return from callback means
 911                  * go ahead and allow the extension,
 912                  * it's what we get if the callback is
 913                  * unhandled
 914                  */
 915
 916                 if (n) {
 917                         ext++;
 918                         continue;
 919                 }
 920
 921                 /* apply it */
 922
 923                 if (ext_count)
 924                         *p++ = ',';
 925                 p += sprintf(p, "%s", ext->name);
 926                 ext_count++;
 927
 928                 ext++;
 929         }
 930 #endif
 931         p += sprintf(p, "\x0d\x0a");
 932
 933         if (wsi->ietf_spec_revision)
 934                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 935                                                wsi->ietf_spec_revision);
 936
 937         /* give userland a chance to append, eg, cookies */
 938
 939         context->protocols[0].callback(context, wsi,
 940                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 941                 NULL, &p, (pkt + sizeof(context->service_buffer)) - p - 12);
 942
 943         p += sprintf(p, "\x0d\x0a");
 944
 945         /* prepare the expected server accept response */
 946
 947         key_b64[39] = '\0'; /* enforce composed length below buf sizeof */
 948         n = sprintf(buf, "%s258EAFA5-E914-47DA-95CA-C5AB0DC85B11", key_b64);
 949
 950         SHA1((unsigned char *)buf, n, (unsigned char *)hash);
 951
 952         lws_b64_encode_string(hash, 20,
 953                         wsi->u.hdr.ah->initial_handshake_hash_base64,
 954                           sizeof(wsi->u.hdr.ah->initial_handshake_hash_base64));
 955
 956         return p;
 957 }
 958