lib/client.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2013 Andy Green <andy@warmcat.com>
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Lesser General Public
   8  *  License as published by the Free Software Foundation:
   9  *  version 2.1 of the License.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Lesser General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Lesser General Public
  17  *  License along with this library; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "private-libwebsockets.h"
  23
  24 #ifdef WIN32
  25 #include <tchar.h>
  26 #include <io.h>
  27 #else
  28 #ifdef LWS_BUILTIN_GETIFADDRS
  29 #include <getifaddrs.h>
  30 #else
  31 #include <ifaddrs.h>
  32 #endif
  33 #include <sys/un.h>
  34 #include <sys/socket.h>
  35 #include <netdb.h>
  36 #endif
  37
  38 int lws_client_socket_service(struct libwebsocket_context *context,
  39                                 struct libwebsocket *wsi, struct pollfd *pollfd)
  40 {
  41         int n;
  42         char *p = (char *)&context->service_buffer[0];
  43         int len;
  44         char c;
  45
  46         switch (wsi->mode) {
  47
  48         case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
  49
  50                 /* handle proxy hung up on us */
  51
  52                 if (pollfd->revents & (POLLERR | POLLHUP)) {
  53
  54                         lwsl_warn("Proxy connection %p (fd=%d) dead\n",
  55                                 (void *)wsi, pollfd->fd);
  56
  57                         libwebsocket_close_and_free_session(context, wsi,
  58                                                      LWS_CLOSE_STATUS_NOSTATUS);
  59                         return 0;
  60                 }
  61
  62                 n = recv(wsi->sock, context->service_buffer,
  63                                         sizeof(context->service_buffer), 0);
  64                 if (n < 0) {
  65                         libwebsocket_close_and_free_session(context, wsi,
  66                                                      LWS_CLOSE_STATUS_NOSTATUS);
  67                         lwsl_err("ERROR reading from proxy socket\n");
  68                         return 0;
  69                 }
  70
  71                 context->service_buffer[13] = '\0';
  72                 if (strcmp((char *)context->service_buffer, "HTTP/1.0 200 ")) {
  73                         libwebsocket_close_and_free_session(context, wsi,
  74                                                      LWS_CLOSE_STATUS_NOSTATUS);
  75                         lwsl_err("ERROR proxy: %s\n", context->service_buffer);
  76                         return 0;
  77                 }
  78
  79                 /* clear his proxy connection timeout */
  80
  81                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
  82
  83                 /* fallthru */
  84
  85         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
  86
  87                 /*
  88                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
  89                  * timeout protection set in client-handshake.c
  90                  */
  91
  92         #ifdef LWS_OPENSSL_SUPPORT
  93
  94                 /*
  95                  * take care of our libwebsocket_callback_on_writable
  96                  * happening at a time when there's no real connection yet
  97                  */
  98
  99                 pollfd->events &= ~POLLOUT;
 100
 101                 /* external POLL support via protocol 0 */
 102                 context->protocols[0].callback(context, wsi,
 103                         LWS_CALLBACK_CLEAR_MODE_POLL_FD,
 104                         (void *)(long)wsi->sock, NULL, POLLOUT);
 105
 106                 /* we can retry this... just cook the SSL BIO the first time */
 107
 108                 if (wsi->use_ssl && !wsi->ssl) {
 109
 110                         wsi->ssl = SSL_new(context->ssl_client_ctx);
 111
 112 #ifdef USE_CYASSL
 113                         /*
 114                          * CyaSSL does certificate verification differently
 115                          * from OpenSSL.
 116                          * If we should ignore the certificate, we need to set
 117                          * this before SSL_new and SSL_connect is called.
 118                          * Otherwise the connect will simply fail with error
 119                          * code -155
 120                          */
 121                         if (wsi->use_ssl == 2)
 122                                 CyaSSL_set_verify(wsi->ssl,
 123                                                         SSL_VERIFY_NONE, NULL);
 124 #endif /* USE_CYASSL */
 125
 126                         wsi->client_bio =
 127                                 BIO_new_socket(wsi->sock, BIO_NOCLOSE);
 128                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 129
 130 #ifdef USE_CYASSL
 131                         CyaSSL_set_using_nonblock(wsi->ssl, 1);
 132 #else
 133                         BIO_set_nbio(wsi->client_bio, 1); /* nonblocking */
 134 #endif
 135
 136                         SSL_set_ex_data(wsi->ssl,
 137                                         openssl_websocket_private_data_index,
 138                                                                        context);
 139                 }
 140
 141                 if (wsi->use_ssl) {
 142                         lws_latency_pre(context, wsi);
 143                         n = SSL_connect(wsi->ssl);
 144                         lws_latency(context, wsi,
 145                           "SSL_connect LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE",
 146                                                                       n, n > 0);
 147
 148                         if (n < 0) {
 149                                 n = SSL_get_error(wsi->ssl, n);
 150
 151                                 if (n == SSL_ERROR_WANT_READ ||
 152                                         n == SSL_ERROR_WANT_WRITE) {
 153                                         /*
 154                                          * wants us to retry connect due to
 155                                          * state of the underlying ssl layer...
 156                                          * but since it may be stalled on
 157                                          * blocked write, no incoming data may
 158                                          * arrive to trigger the retry.
 159                                          * Force (possibly many times if the SSL
 160                                          * state persists in returning the
 161                                          * condition code, but other sockets
 162                                          * are getting serviced inbetweentimes)
 163                                          * us to get called back when writable.
 164                                          */
 165
 166                                         lwsl_info(
 167                                              "SSL_connect WANT_... retrying\n");
 168                                         libwebsocket_callback_on_writable(
 169                                                                   context, wsi);
 170
 171                                         return 0; /* no error */
 172                                 }
 173                                 n = -1;
 174                         }
 175
 176                         if (n <= 0) {
 177                                 /*
 178                                  * retry if new data comes until we
 179                                  * run into the connection timeout or win
 180                                  */
 181
 182                                 lwsl_err("SSL connect error %s\n",
 183                                         ERR_error_string(ERR_get_error(),
 184                                               (char *)context->service_buffer));
 185                                 return 0;
 186                         }
 187
 188                         #ifndef USE_CYASSL
 189                         /*
 190                          * See comment above about CyaSSL certificate
 191                          * verification
 192                          */
 193                         lws_latency_pre(context, wsi);
 194                         n = SSL_get_verify_result(wsi->ssl);
 195                         lws_latency(context, wsi,
 196                                 "SSL_get_verify_result LWS_CONNMODE..HANDSHAKE",
 197                                                                       n, n > 0);
 198                         if ((n != X509_V_OK) && (
 199                                 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 200                                                            wsi->use_ssl != 2)) {
 201
 202                                 lwsl_err(
 203                                       "server's cert didn't look good %d\n", n);
 204                                 libwebsocket_close_and_free_session(context,
 205                                                 wsi, LWS_CLOSE_STATUS_NOSTATUS);
 206                                 return 0;
 207                         }
 208 #endif /* USE_CYASSL */
 209                 } else
 210                         wsi->ssl = NULL;
 211 #endif
 212
 213                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 214                 if (p == NULL) {
 215                         lwsl_err("Failed to generate handshake for client\n");
 216                         libwebsocket_close_and_free_session(context, wsi,
 217                                                      LWS_CLOSE_STATUS_NOSTATUS);
 218                         return 0;
 219                 }
 220
 221                 /* send our request to the server */
 222
 223                 lws_latency_pre(context, wsi);
 224 #ifdef LWS_OPENSSL_SUPPORT
 225                 if (wsi->use_ssl)
 226                         n = SSL_write(wsi->ssl, context->service_buffer,
 227                                            p - (char *)context->service_buffer);
 228                 else
 229 #endif
 230                         n = send(wsi->sock, context->service_buffer,
 231                                         p - (char *)context->service_buffer, 0);
 232                 lws_latency(context, wsi,
 233                         "send or SSL_write LWS_CONNMODE...HANDSHAKE",
 234                                                                      n, n >= 0);
 235
 236                 if (n < 0) {
 237                         lwsl_debug("ERROR writing to client socket\n");
 238                         libwebsocket_close_and_free_session(context, wsi,
 239                                                      LWS_CLOSE_STATUS_NOSTATUS);
 240                         return 0;
 241                 }
 242
 243                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 244                 wsi->u.hdr.lextable_pos = 0;
 245                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 246                 libwebsocket_set_timeout(wsi,
 247                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE,
 248                                                               AWAITING_TIMEOUT);
 249                 break;
 250
 251         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 252
 253                 /* handle server hung up on us */
 254
 255                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 256
 257                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 258                                 (void *)wsi, pollfd->fd);
 259
 260                         goto bail3;
 261                 }
 262
 263                 if (!(pollfd->revents & POLLIN))
 264                         goto bail3;
 265
 266                 /* interpret the server response */
 267
 268                 /*
 269                  *  HTTP/1.1 101 Switching Protocols
 270                  *  Upgrade: websocket
 271                  *  Connection: Upgrade
 272                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 273                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 274                  *  Sec-WebSocket-Protocol: chat
 275                  */
 276
 277                 /*
 278                  * we have to take some care here to only take from the
 279                  * socket bytewise.  The browser may (and has been seen to
 280                  * in the case that onopen() performs websocket traffic)
 281                  * coalesce both handshake response and websocket traffic
 282                  * in one packet, since at that point the connection is
 283                  * definitively ready from browser pov.
 284                  */
 285
 286                 len = 1;
 287                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE &&
 288                                                                       len > 0) {
 289 #ifdef LWS_OPENSSL_SUPPORT
 290                         if (wsi->use_ssl) {
 291                                 len = SSL_read(wsi->ssl, &c, 1);
 292                                 if (len < 0) {
 293                                         n = SSL_get_error(wsi->ssl, len);
 294                                         if (n ==  SSL_ERROR_WANT_READ ||
 295                                                      n ==  SSL_ERROR_WANT_WRITE)
 296                                                 return 0;
 297                                 }
 298                         } else
 299 #endif
 300                                 len = recv(wsi->sock, &c, 1, 0);
 301
 302                         if (len < 0)
 303                                 goto bail3;
 304
 305                         if (libwebsocket_parse(wsi, c)) {
 306                                 /* problems */
 307                                 goto bail3;
 308                         }
 309                 }
 310
 311                 /*
 312                  * hs may also be coming in multiple packets, there is a 5-sec
 313                  * libwebsocket timeout still active here too, so if parsing did
 314                  * not complete just wait for next packet coming in this state
 315                  */
 316
 317                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 318                         break;
 319
 320                 /*
 321                  * otherwise deal with the handshake.  If there's any
 322                  * packet traffic already arrived we'll trigger poll() again
 323                  * right away and deal with it that way
 324                  */
 325
 326                 return lws_client_interpret_server_handshake(context, wsi);
 327
 328 bail3:
 329                 lwsl_info(
 330                         "closing connection at LWS_CONNMODE...SERVER_REPLY\n");
 331                 libwebsocket_close_and_free_session(context, wsi,
 332                                                     LWS_CLOSE_STATUS_NOSTATUS);
 333                 return 0;
 334
 335         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 336                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 337                 break;
 338
 339         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 340                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 341                 break;
 342         default:
 343                 break;
 344         }
 345
 346         return 0;
 347 }
 348
 349
 350 /*
 351  * In-place str to lower case
 352  */
 353
 354 static void
 355 strtolower(char *s)
 356 {
 357         while (*s) {
 358                 *s = tolower(*s);
 359                 s++;
 360         }
 361 }
 362
 363 int
 364 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 365                 struct libwebsocket *wsi)
 366 {
 367         const char *pc;
 368         int okay = 0;
 369         char *p;
 370         int len;
 371 #ifndef LWS_NO_EXTENSIONS
 372         char ext_name[128];
 373         struct libwebsocket_extension *ext;
 374         void *v;
 375         int more = 1;
 376         const char *c;
 377 #endif
 378         int n;
 379
 380         /*
 381          * well, what the server sent looked reasonable for syntax.
 382          * Now let's confirm it sent all the necessary headers
 383          */
 384
 385         if (lws_hdr_total_length(wsi, WSI_TOKEN_ACCEPT) == 0)
 386                 goto bail3;
 387
 388         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP);
 389         if (!p)
 390                 goto bail3;
 391         if (p && strncmp(p, "101", 3)) {
 392                 lwsl_warn(
 393                        "lws_client_handshake: got bad HTTP response '%s'\n", p);
 394                 goto bail3;
 395         }
 396
 397         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_UPGRADE);
 398         if (!p)
 399                 goto bail3;
 400         strtolower(p);
 401         if (strcmp(p, "websocket")) {
 402                 lwsl_warn(
 403                       "lws_client_handshake: got bad Upgrade header '%s'\n", p);
 404                 goto bail3;
 405         }
 406
 407         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_CONNECTION);
 408         if (!p)
 409                 goto bail3;
 410         strtolower(p);
 411         if (strcmp(p, "upgrade")) {
 412                 lwsl_warn("lws_client_int_s_hs: bad header %s\n", p);
 413                 goto bail3;
 414         }
 415
 416         pc = lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS);
 417         if (pc == NULL)
 418                 lwsl_parser("lws_client_int_s_hs: no protocol list\n");
 419         else
 420                 lwsl_parser("lws_client_int_s_hs: protocol list '%s'\n", pc);
 421
 422         /*
 423          * confirm the protocol the server wants to talk was in the list
 424          * of protocols we offered
 425          */
 426
 427         len = lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL);
 428         if (!len) {
 429
 430                 lwsl_info("lws_client_int_s_hs: WSI_TOKEN_PROTOCOL is null\n");
 431                 /*
 432                  * no protocol name to work from,
 433                  * default to first protocol
 434                  */
 435                 wsi->protocol = &context->protocols[0];
 436                 goto check_extensions;
 437         }
 438
 439         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL);
 440         len = strlen(p);
 441
 442         while (*pc && !okay) {
 443                 if (!strncmp(pc, p, len) &&
 444                                           (pc[len] == ',' || pc[len] == '\0')) {
 445                         okay = 1;
 446                         continue;
 447                 }
 448                 while (*pc && *pc != ',')
 449                         pc++;
 450                 while (*pc && *pc != ' ')
 451                         pc++;
 452         }
 453
 454         if (!okay) {
 455                 lwsl_err("lws_client_int_s_hs: got bad protocol %s\n", p);
 456                 goto bail2;
 457         }
 458
 459         /*
 460          * identify the selected protocol struct and set it
 461          */
 462         n = 0;
 463         wsi->protocol = NULL;
 464         while (context->protocols[n].callback && !wsi->protocol) {
 465                 if (strcmp(p, context->protocols[n].name) == 0) {
 466                         wsi->protocol = &context->protocols[n];
 467                         break;
 468                 }
 469                 n++;
 470         }
 471
 472         if (wsi->protocol == NULL) {
 473                 lwsl_err("lws_client_int_s_hs: fail protocol %s\n", p);
 474                 goto bail2;
 475         }
 476
 477
 478 check_extensions:
 479 #ifndef LWS_NO_EXTENSIONS
 480         /* instantiate the accepted extensions */
 481
 482         if (!lws_hdr_total_length(wsi, WSI_TOKEN_EXTENSIONS)) {
 483                 lwsl_ext("no client extenstions allowed by server\n");
 484                 goto check_accept;
 485         }
 486
 487         /*
 488          * break down the list of server accepted extensions
 489          * and go through matching them or identifying bogons
 490          */
 491
 492         if (lws_hdr_copy(wsi, (char *)context->service_buffer,
 493                      sizeof(context->service_buffer), WSI_TOKEN_EXTENSIONS) < 0)
 494                 goto bail2;
 495
 496         c = (char *)context->service_buffer;
 497         n = 0;
 498         while (more) {
 499
 500                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 501                         ext_name[n] = *c++;
 502                         if (n < sizeof(ext_name) - 1)
 503                                 n++;
 504                         continue;
 505                 }
 506                 ext_name[n] = '\0';
 507                 if (!*c)
 508                         more = 0;
 509                 else {
 510                         c++;
 511                         if (!n)
 512                                 continue;
 513                 }
 514
 515                 /* check we actually support it */
 516
 517                 lwsl_ext("checking client ext %s\n", ext_name);
 518
 519                 n = 0;
 520                 ext = wsi->protocol->owning_server->extensions;
 521                 while (ext && ext->callback) {
 522
 523                         if (strcmp(ext_name, ext->name)) {
 524                                 ext++;
 525                                 continue;
 526                         }
 527
 528                         n = 1;
 529
 530                         lwsl_ext("instantiating client ext %s\n", ext_name);
 531
 532                         /* instantiate the extension on this conn */
 533
 534                         wsi->active_extensions_user[
 535                                 wsi->count_active_extensions] =
 536                                          malloc(ext->per_session_data_size);
 537                         if (wsi->active_extensions_user[
 538                                 wsi->count_active_extensions] == NULL) {
 539                                 lwsl_err("Out of mem\n");
 540                                 goto bail2;
 541                         }
 542                         memset(wsi->active_extensions_user[
 543                                 wsi->count_active_extensions], 0,
 544                                                     ext->per_session_data_size);
 545                         wsi->active_extensions[
 546                                   wsi->count_active_extensions] = ext;
 547
 548                         /* allow him to construct his context */
 549
 550                         ext->callback(wsi->protocol->owning_server,
 551                                 ext, wsi,
 552                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 553                                         wsi->active_extensions_user[
 554                                          wsi->count_active_extensions],
 555                                                                    NULL, 0);
 556
 557                         wsi->count_active_extensions++;
 558
 559                         ext++;
 560                 }
 561
 562                 if (n == 0) {
 563                         lwsl_warn("Unknown ext '%s'!\n", ext_name);
 564                         goto bail2;
 565                 }
 566
 567                 n = 0;
 568         }
 569
 570 check_accept:
 571 #endif
 572
 573         /*
 574          * Confirm his accept token is the one we precomputed
 575          */
 576
 577         p = lws_hdr_simple_ptr(wsi, WSI_TOKEN_ACCEPT);
 578         if (strcmp(p, wsi->u.hdr.initial_handshake_hash_base64)) {
 579                 lwsl_warn("lws_client_int_s_hs: accept %s wrong vs %s\n", p,
 580                                       wsi->u.hdr.initial_handshake_hash_base64);
 581                 goto bail2;
 582         }
 583
 584         /* allocate the per-connection user memory (if any) */
 585         if (wsi->protocol->per_session_data_size &&
 586                                           !libwebsocket_ensure_user_space(wsi))
 587                 goto bail2;
 588
 589         /*
 590          * we seem to be good to go, give client last chance to check
 591          * headers and OK it
 592          */
 593
 594         wsi->protocol->callback(context, wsi,
 595                                 LWS_CALLBACK_CLIENT_FILTER_PRE_ESTABLISH,
 596                                                      wsi->user_space, NULL, 0);
 597
 598         /* clear his proxy connection timeout */
 599
 600         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 601
 602         /* free up his parsing allocations */
 603         if (wsi->u.hdr.ah)
 604                 free(wsi->u.hdr.ah);
 605
 606         /* mark him as being alive */
 607
 608         wsi->state = WSI_STATE_ESTABLISHED;
 609         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 610
 611         /* union transition */
 612
 613         memset(&wsi->u, 0, sizeof(wsi->u));
 614
 615         /*
 616          * create the frame buffer for this connection according to the
 617          * size mentioned in the protocol definition.  If 0 there, then
 618          * use a big default for compatibility
 619          */
 620
 621         n = wsi->protocol->rx_buffer_size;
 622         if (!n)
 623                 n = LWS_MAX_SOCKET_IO_BUF;
 624         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 625         wsi->u.ws.rx_user_buffer = malloc(n);
 626         if (!wsi->u.ws.rx_user_buffer) {
 627                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 628                 goto bail3;
 629         }
 630         lwsl_info("Allocating client RX buffer %d\n", n);
 631
 632         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 633
 634         /* call him back to inform him he is up */
 635
 636         wsi->protocol->callback(context, wsi,
 637                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 638                                                      wsi->user_space, NULL, 0);
 639 #ifndef LWS_NO_EXTENSIONS
 640         /*
 641          * inform all extensions, not just active ones since they
 642          * already know
 643          */
 644
 645         ext = context->extensions;
 646
 647         while (ext && ext->callback) {
 648                 v = NULL;
 649                 for (n = 0; n < wsi->count_active_extensions; n++)
 650                         if (wsi->active_extensions[n] == ext)
 651                                 v = wsi->active_extensions_user[n];
 652
 653                 ext->callback(context, ext, wsi,
 654                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 655                 ext++;
 656         }
 657 #endif
 658
 659         return 0;
 660
 661 bail3:
 662
 663 bail2:
 664         if (wsi->protocol)
 665                 wsi->protocol->callback(context, wsi,
 666                         LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 667                                                       wsi->user_space, NULL, 0);
 668
 669         lwsl_info("closing connection due to bail2 connection error\n");
 670
 671         /* free up his parsing allocations */
 672
 673         if (wsi->u.hdr.ah)
 674                 free(wsi->u.hdr.ah);
 675
 676         libwebsocket_close_and_free_session(context, wsi,
 677                                                  LWS_CLOSE_STATUS_PROTOCOL_ERR);
 678
 679         return 1;
 680 }
 681
 682
 683 char *
 684 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 685                 struct libwebsocket *wsi, char *pkt)
 686 {
 687         char buf[128];
 688         char hash[20];
 689         char key_b64[40];
 690         char *p = pkt;
 691         int n;
 692 #ifndef LWS_NO_EXTENSIONS
 693         struct libwebsocket_extension *ext;
 694         struct libwebsocket_extension *ext1;
 695         int ext_count = 0;
 696 #endif
 697         static const char magic_websocket_guid[] =
 698                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 699
 700         /*
 701          * create the random key
 702          */
 703
 704         n = libwebsockets_get_random(context, hash, 16);
 705         if (n != 16) {
 706                 lwsl_err("Unable to read from random dev %s\n",
 707                                                 SYSTEM_RANDOM_FILEPATH);
 708                 libwebsocket_close_and_free_session(context, wsi,
 709                                              LWS_CLOSE_STATUS_NOSTATUS);
 710                 return NULL;
 711         }
 712
 713         lws_b64_encode_string(hash, 16, key_b64, sizeof(key_b64));
 714
 715         /*
 716          * 00 example client handshake
 717          *
 718          * GET /socket.io/websocket HTTP/1.1
 719          * Upgrade: WebSocket
 720          * Connection: Upgrade
 721          * Host: 127.0.0.1:9999
 722          * Origin: http://127.0.0.1
 723          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 724          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 725          * Cookie: socketio=websocket
 726          *
 727          * (Á®Ä0¶†≥
 728          *
 729          * 04 example client handshake
 730          *
 731          * GET /chat HTTP/1.1
 732          * Host: server.example.com
 733          * Upgrade: websocket
 734          * Connection: Upgrade
 735          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 736          * Sec-WebSocket-Origin: http://example.com
 737          * Sec-WebSocket-Protocol: chat, superchat
 738          * Sec-WebSocket-Version: 4
 739          */
 740
 741         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a",
 742                                 lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_URI));
 743
 744         p += sprintf(p,
 745                 "Pragma: no-cache\x0d\x0a""Cache-Control: no-cache\x0d\x0a");
 746
 747         p += sprintf(p, "Host: %s\x0d\x0a",
 748                                lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_HOST));
 749         p += sprintf(p,
 750 "Upgrade: websocket\x0d\x0aConnection: Upgrade\x0d\x0aSec-WebSocket-Key: ");
 751         strcpy(p, key_b64);
 752         p += strlen(key_b64);
 753         p += sprintf(p, "\x0d\x0a");
 754         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN))
 755                 p += sprintf(p, "Origin: %s\x0d\x0a",
 756                              lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_ORIGIN));
 757
 758         if (lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS))
 759                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 760                      lws_hdr_simple_ptr(wsi, _WSI_TOKEN_CLIENT_SENT_PROTOCOLS));
 761
 762         /* tell the server what extensions we could support */
 763
 764         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 765 #ifndef LWS_NO_EXTENSIONS
 766         ext = context->extensions;
 767         while (ext && ext->callback) {
 768
 769                 n = 0;
 770                 ext1 = context->extensions;
 771
 772                 while (ext1 && ext1->callback) {
 773                         n |= ext1->callback(context, ext1, wsi,
 774                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 775                                         NULL, (char *)ext->name, 0);
 776
 777                         ext1++;
 778                 }
 779
 780                 if (n) { /* an extension vetos us */
 781                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 782                         ext++;
 783                         continue;
 784                 }
 785
 786                 n = context->protocols[0].callback(context, wsi,
 787                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 788                                 wsi->user_space, (char *)ext->name, 0);
 789
 790                 /*
 791                  * zero return from callback means
 792                  * go ahead and allow the extension,
 793                  * it's what we get if the callback is
 794                  * unhandled
 795                  */
 796
 797                 if (n) {
 798                         ext++;
 799                         continue;
 800                 }
 801
 802                 /* apply it */
 803
 804                 if (ext_count)
 805                         *p++ = ',';
 806                 p += sprintf(p, "%s", ext->name);
 807                 ext_count++;
 808
 809                 ext++;
 810         }
 811 #endif
 812         p += sprintf(p, "\x0d\x0a");
 813
 814         if (wsi->ietf_spec_revision)
 815                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 816                                                wsi->ietf_spec_revision);
 817
 818         /* give userland a chance to append, eg, cookies */
 819
 820         context->protocols[0].callback(context, wsi,
 821                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 822                 NULL, &p, (pkt + sizeof(context->service_buffer)) - p - 12);
 823
 824         p += sprintf(p, "\x0d\x0a");
 825
 826         /* prepare the expected server accept response */
 827
 828         n = snprintf(buf, sizeof(buf), "%s%s", key_b64, magic_websocket_guid);
 829         buf[sizeof(buf) - 1] = '\0';
 830         SHA1((unsigned char *)buf, n, (unsigned char *)hash);
 831
 832         lws_b64_encode_string(hash, 20,
 833                         wsi->u.hdr.initial_handshake_hash_base64,
 834                              sizeof(wsi->u.hdr.initial_handshake_hash_base64));
 835
 836         return p;
 837 }
 838