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 #ifdef LWS_OPENSSL_SUPPORT
  39 extern int openssl_websocket_private_data_index;
  40 #endif
  41
  42 int lws_client_socket_service(struct libwebsocket_context *context, struct libwebsocket *wsi, struct pollfd *pollfd)
  43 {
  44         int n;
  45         char pkt[1024];
  46         char *p = &pkt[0];
  47         int len;
  48         char c;
  49 #ifdef LWS_OPENSSL_SUPPORT
  50         char ssl_err_buf[512];
  51 #endif
  52
  53         switch (wsi->mode) {
  54
  55         case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
  56
  57                 /* handle proxy hung up on us */
  58
  59                 if (pollfd->revents & (POLLERR | POLLHUP)) {
  60
  61                         lwsl_warn("Proxy connection %p (fd=%d) dead\n",
  62                                 (void *)wsi, pollfd->fd);
  63
  64                         libwebsocket_close_and_free_session(context, wsi,
  65                                                      LWS_CLOSE_STATUS_NOSTATUS);
  66                         return 0;
  67                 }
  68
  69                 n = recv(wsi->sock, pkt, sizeof pkt, 0);
  70                 if (n < 0) {
  71                         libwebsocket_close_and_free_session(context, wsi,
  72                                                      LWS_CLOSE_STATUS_NOSTATUS);
  73                         lwsl_err("ERROR reading from proxy socket\n");
  74                         return 0;
  75                 }
  76
  77                 pkt[13] = '\0';
  78                 if (strcmp(pkt, "HTTP/1.0 200 ") != 0) {
  79                         libwebsocket_close_and_free_session(context, wsi,
  80                                                      LWS_CLOSE_STATUS_NOSTATUS);
  81                         lwsl_err("ERROR from proxy: %s\n", pkt);
  82                         return 0;
  83                 }
  84
  85                 /* clear his proxy connection timeout */
  86
  87                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
  88
  89                 /* fallthru */
  90
  91         case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
  92
  93                 /*
  94                  * we are under PENDING_TIMEOUT_SENT_CLIENT_HANDSHAKE
  95                  * timeout protection set in client-handshake.c
  96                  */
  97
  98         #ifdef LWS_OPENSSL_SUPPORT
  99
 100                 /*
 101                  * take care of our libwebsocket_callback_on_writable
 102                  * happening at a time when there's no real connection yet
 103                  */
 104
 105                 pollfd->events &= ~POLLOUT;
 106
 107                 /* external POLL support via protocol 0 */
 108                 context->protocols[0].callback(context, wsi,
 109                         LWS_CALLBACK_CLEAR_MODE_POLL_FD,
 110                         (void *)(long)wsi->sock, NULL, POLLOUT);
 111
 112                 /* we can retry this... so just cook the SSL BIO the first time */
 113
 114                 if (wsi->use_ssl && !wsi->ssl) {
 115
 116                         wsi->ssl = SSL_new(context->ssl_client_ctx);
 117                         wsi->client_bio = BIO_new_socket(wsi->sock,
 118                                                                    BIO_NOCLOSE);
 119
 120                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 121
 122                         BIO_set_nbio(wsi->client_bio, 1); /* nonblocking */
 123
 124                         SSL_set_ex_data(wsi->ssl,
 125                                         openssl_websocket_private_data_index,
 126                                                                        context);
 127                 }
 128
 129                 if (wsi->use_ssl) {
 130                         lws_latency_pre(context, wsi);
 131                         n = SSL_connect(wsi->ssl);
 132                         lws_latency(context, wsi, "SSL_connect LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n > 0);
 133
 134                         if (n < 0) {
 135                                 n = SSL_get_error(wsi->ssl, n);
 136
 137                                 if (n == SSL_ERROR_WANT_READ ||
 138                                         n == SSL_ERROR_WANT_WRITE) {
 139                                         /*
 140                                          * wants us to retry connect due to state of the
 141                                          * underlying ssl layer... but since it may be
 142                                          * stalled on blocked write, no incoming data may
 143                                          * arrive to trigger the retry.  Force (possibly
 144                                          * many if the SSL state persists in returning the
 145                                          * condition code, but other sockets are getting
 146                                          * serviced inbetweentimes) us to get called back
 147                                          * when writable.
 148                                          */
 149
 150                                         lwsl_info("SSL_connect -> SSL_ERROR_WANT_... retrying\n");
 151                                         libwebsocket_callback_on_writable(context, wsi);
 152
 153                                         return 0; /* no error */
 154                                 }
 155                                 n = -1;
 156                         }
 157
 158                         if (n <= 0) {
 159                                 /*
 160                                  * retry if new data comes until we
 161                                  * run into the connection timeout or win
 162                                  */
 163
 164                                 lwsl_err("SSL connect error %s\n",
 165                                         ERR_error_string(ERR_get_error(),
 166                                                                   ssl_err_buf));
 167                                 return 0;
 168                         }
 169
 170                         lws_latency_pre(context, wsi);
 171                         n = SSL_get_verify_result(wsi->ssl);
 172                         lws_latency(context, wsi, "SSL_get_verify_result LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n > 0);
 173                         if ((n != X509_V_OK) && (
 174                                 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 175                                                            wsi->use_ssl != 2)) {
 176
 177                                 lwsl_err("server's cert didn't "
 178                                                            "look good %d\n", n);
 179                                 libwebsocket_close_and_free_session(context,
 180                                                 wsi, LWS_CLOSE_STATUS_NOSTATUS);
 181                                 return 0;
 182                         }
 183                 } else
 184                         wsi->ssl = NULL;
 185         #endif
 186
 187                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 188                 if (p == NULL) {
 189                         lwsl_err("Failed to generate handshake for client, closing it\n");
 190                         libwebsocket_close_and_free_session(context, wsi,
 191                                                      LWS_CLOSE_STATUS_NOSTATUS);
 192                         return 0;
 193                 }
 194
 195                 /* send our request to the server */
 196
 197                 lws_latency_pre(context, wsi);
 198         #ifdef LWS_OPENSSL_SUPPORT
 199                 if (wsi->use_ssl)
 200                         n = SSL_write(wsi->ssl, pkt, p - pkt);
 201                 else
 202         #endif
 203                         n = send(wsi->sock, pkt, p - pkt, 0);
 204                 lws_latency(context, wsi, "send or SSL_write LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE", n, n >= 0);
 205
 206                 if (n < 0) {
 207                         lwsl_debug("ERROR writing to client socket\n");
 208                         libwebsocket_close_and_free_session(context, wsi,
 209                                                      LWS_CLOSE_STATUS_NOSTATUS);
 210                         return 0;
 211                 }
 212
 213                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 214                 wsi->u.hdr.lextable_pos = 0;
 215                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 216                 libwebsocket_set_timeout(wsi,
 217                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE, AWAITING_TIMEOUT);
 218
 219                 break;
 220
 221         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 222
 223                 /* handle server hung up on us */
 224
 225                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 226
 227                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 228                                 (void *)wsi, pollfd->fd);
 229
 230                         goto bail3;
 231                 }
 232
 233                 if (!(pollfd->revents & POLLIN))
 234                         goto bail3;
 235
 236                 /* interpret the server response */
 237
 238                 /*
 239                  *  HTTP/1.1 101 Switching Protocols
 240                  *  Upgrade: websocket
 241                  *  Connection: Upgrade
 242                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 243                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 244                  *  Sec-WebSocket-Protocol: chat
 245                  */
 246
 247                 /*
 248                  * we have to take some care here to only take from the
 249                  * socket bytewise.  The browser may (and has been seen to
 250                  * in the case that onopen() performs websocket traffic)
 251                  * coalesce both handshake response and websocket traffic
 252                  * in one packet, since at that point the connection is
 253                  * definitively ready from browser pov.
 254                  */
 255
 256                 len = 1;
 257                 while (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE && len > 0) {
 258 #ifdef LWS_OPENSSL_SUPPORT
 259                         if (wsi->use_ssl) {
 260                                 len = SSL_read(wsi->ssl, &c, 1);
 261                                 if (len < 0) {
 262                                         n = SSL_get_error(wsi->ssl, len);
 263                                         if (n ==  SSL_ERROR_WANT_READ ||
 264                                                         n ==  SSL_ERROR_WANT_WRITE)
 265                                                 return 0;
 266                                 }
 267                         } else
 268 #endif
 269                                 len = recv(wsi->sock, &c, 1, 0);
 270
 271                         if (len < 0)
 272                                 goto bail3;
 273
 274                         libwebsocket_parse(wsi, c);
 275                 }
 276
 277                 /*
 278                  * hs may also be coming in multiple packets, there is a 5-sec
 279                  * libwebsocket timeout still active here too, so if parsing did
 280                  * not complete just wait for next packet coming in this state
 281                  */
 282
 283                 if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 284                         break;
 285
 286                 /*
 287                  * otherwise deal with the handshake.  If there's any
 288                  * packet traffic already arrived we'll trigger poll() again
 289                  * right away and deal with it that way
 290                  */
 291
 292                 return lws_client_interpret_server_handshake(context, wsi);
 293
 294 bail3:
 295                 if (wsi->c_protocol)
 296                         free(wsi->c_protocol);
 297                 lwsl_info("closing connection at LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY\n");
 298                 libwebsocket_close_and_free_session(context, wsi,
 299                                                     LWS_CLOSE_STATUS_NOSTATUS);
 300                 return 0;
 301
 302         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 303                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 304                 break;
 305
 306         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 307                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 308                 break;
 309         default:
 310                 break;
 311         }
 312
 313         return 0;
 314 }
 315
 316
 317 /*
 318  * In-place str to lower case
 319  */
 320
 321 static void
 322 strtolower(char *s)
 323 {
 324         while (*s) {
 325                 *s = tolower(*s);
 326                 s++;
 327         }
 328 }
 329
 330 int
 331 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 332                 struct libwebsocket *wsi)
 333 {
 334         const char *pc;
 335         int okay = 0;
 336 #ifndef LWS_NO_EXTENSIONS
 337         char ext_name[128];
 338         struct libwebsocket_extension *ext;
 339         void *v;
 340         int more = 1;
 341         const char *c;
 342 #endif
 343         int n;
 344
 345         /*
 346          * well, what the server sent looked reasonable for syntax.
 347          * Now let's confirm it sent all the necessary headers
 348          */
 349 #if 0
 350         lwsl_parser("WSI_TOKEN_HTTP: %d\n",
 351                                     wsi->utf8_token[WSI_TOKEN_HTTP].token_len);
 352         lwsl_parser("WSI_TOKEN_UPGRADE: %d\n",
 353                                  wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len);
 354         lwsl_parser("WSI_TOKEN_CONNECTION: %d\n",
 355                               wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len);
 356         lwsl_parser("WSI_TOKEN_ACCEPT: %d\n",
 357                                   wsi->utf8_token[WSI_TOKEN_ACCEPT].token_len);
 358         lwsl_parser("WSI_TOKEN_NONCE: %d\n",
 359                                    wsi->utf8_token[WSI_TOKEN_NONCE].token_len);
 360         lwsl_parser("WSI_TOKEN_PROTOCOL: %d\n",
 361                                 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len);
 362 #endif
 363
 364         strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
 365         if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
 366                 lwsl_warn("libwebsocket_client_handshake "
 367                                 "server sent bad HTTP response '%s'\n",
 368                                  wsi->utf8_token[WSI_TOKEN_HTTP].token);
 369                 goto bail3;
 370         }
 371
 372         strtolower(wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 373         if (strcmp(wsi->utf8_token[WSI_TOKEN_UPGRADE].token,
 374                                                          "websocket")) {
 375                 lwsl_warn("libwebsocket_client_handshake server "
 376                                 "sent bad Upgrade header '%s'\n",
 377                                   wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 378                 goto bail3;
 379         }
 380
 381         strtolower(wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 382         if (strcmp(wsi->utf8_token[WSI_TOKEN_CONNECTION].token,
 383                                                            "upgrade")) {
 384                 lwsl_warn("libwebsocket_client_handshake server "
 385                                 "sent bad Connection hdr '%s'\n",
 386                            wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 387                 goto bail3;
 388         }
 389
 390         pc = wsi->c_protocol;
 391         if (pc == NULL)
 392                 lwsl_parser("lws_client_interpret_server_handshake: "
 393                                                           "NULL c_protocol\n");
 394         else
 395                 lwsl_parser("lws_client_interpret_server_handshake: "
 396                                                       "cPprotocol='%s'\n", pc);
 397
 398         /*
 399          * confirm the protocol the server wants to talk was in the list
 400          * of protocols we offered
 401          */
 402
 403         if (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len) {
 404
 405                 lwsl_info("lws_client_interpret_server_handshake "
 406                                                "WSI_TOKEN_PROTOCOL is null\n");
 407                 /*
 408                  * no protocol name to work from,
 409                  * default to first protocol
 410                  */
 411                 wsi->protocol = &context->protocols[0];
 412                 wsi->c_callback = wsi->protocol->callback;
 413                 free(wsi->c_protocol);
 414
 415                 goto check_extensions;
 416         }
 417
 418         while (*pc && !okay) {
 419                 if ((!strncmp(pc, wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 420                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len)) &&
 421                  (pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == ',' ||
 422                   pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == '\0')) {
 423                         okay = 1;
 424                         continue;
 425                 }
 426                 while (*pc && *pc != ',')
 427                         pc++;
 428                 while (*pc && *pc != ' ')
 429                         pc++;
 430         }
 431
 432         /* done with him now */
 433
 434         if (wsi->c_protocol)
 435                 free(wsi->c_protocol);
 436
 437         if (!okay) {
 438                 lwsl_err("libwebsocket_client_handshake server "
 439                                         "sent bad protocol '%s'\n",
 440                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 441                 goto bail2;
 442         }
 443
 444         /*
 445          * identify the selected protocol struct and set it
 446          */
 447         n = 0;
 448         wsi->protocol = NULL;
 449         while (context->protocols[n].callback && !wsi->protocol) {  /* Stop after finding first one?? */
 450                 if (strcmp(wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 451                                            context->protocols[n].name) == 0) {
 452                         wsi->protocol = &context->protocols[n];
 453                         wsi->c_callback = wsi->protocol->callback;
 454                 }
 455                 n++;
 456         }
 457
 458         if (wsi->protocol == NULL) {
 459                 lwsl_err("libwebsocket_client_handshake server "
 460                                 "requested protocol '%s', which we "
 461                                 "said we supported but we don't!\n",
 462                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 463                 goto bail2;
 464         }
 465
 466
 467 check_extensions:
 468 #ifndef LWS_NO_EXTENSIONS
 469         /* instantiate the accepted extensions */
 470
 471         if (!wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token_len) {
 472                 lwsl_ext("no client extenstions allowed by server\n");
 473                 goto check_accept;
 474         }
 475
 476         /*
 477          * break down the list of server accepted extensions
 478          * and go through matching them or identifying bogons
 479          */
 480
 481         c = wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token;
 482         n = 0;
 483         while (more) {
 484
 485                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 486                         ext_name[n] = *c++;
 487                         if (n < sizeof(ext_name) - 1)
 488                                 n++;
 489                         continue;
 490                 }
 491                 ext_name[n] = '\0';
 492                 if (!*c)
 493                         more = 0;
 494                 else {
 495                         c++;
 496                         if (!n)
 497                                 continue;
 498                 }
 499
 500                 /* check we actually support it */
 501
 502                 lwsl_ext("checking client ext %s\n", ext_name);
 503
 504                 n = 0;
 505                 ext = wsi->protocol->owning_server->extensions;
 506                 while (ext && ext->callback) {
 507
 508                         if (strcmp(ext_name, ext->name)) {
 509                                 ext++;
 510                                 continue;
 511                         }
 512
 513                         n = 1;
 514
 515                         lwsl_ext("instantiating client ext %s\n", ext_name);
 516
 517                         /* instantiate the extension on this conn */
 518
 519                         wsi->active_extensions_user[
 520                                 wsi->count_active_extensions] =
 521                                          malloc(ext->per_session_data_size);
 522                         if (wsi->active_extensions_user[
 523                                 wsi->count_active_extensions] == NULL) {
 524                                 lwsl_err("Out of mem\n");
 525                                 goto bail2;
 526                         }
 527                         memset(wsi->active_extensions_user[
 528                                 wsi->count_active_extensions], 0,
 529                                                     ext->per_session_data_size);
 530                         wsi->active_extensions[
 531                                   wsi->count_active_extensions] = ext;
 532
 533                         /* allow him to construct his context */
 534
 535                         ext->callback(wsi->protocol->owning_server,
 536                                 ext, wsi,
 537                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 538                                         wsi->active_extensions_user[
 539                                          wsi->count_active_extensions],
 540                                                                    NULL, 0);
 541
 542                         wsi->count_active_extensions++;
 543
 544                         ext++;
 545                 }
 546
 547                 if (n == 0) {
 548                         lwsl_warn("Server said we should use"
 549                                   "an unknown extension '%s'!\n", ext_name);
 550                         goto bail2;
 551                 }
 552
 553                 n = 0;
 554         }
 555
 556 check_accept:
 557 #endif
 558
 559         /*
 560          * Confirm his accept token is the one we precomputed
 561          */
 562
 563         if (strcmp(wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 564                                   wsi->u.hdr.initial_handshake_hash_base64)) {
 565                 lwsl_warn("libwebsocket_client_handshake server "
 566                         "sent bad ACCEPT '%s' vs computed '%s'\n",
 567                         wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 568                                         wsi->u.hdr.initial_handshake_hash_base64);
 569                 goto bail2;
 570         }
 571
 572         /* allocate the per-connection user memory (if any) */
 573         if (wsi->protocol->per_session_data_size &&
 574                                           !libwebsocket_ensure_user_space(wsi))
 575                 goto bail2;
 576
 577         /* clear his proxy connection timeout */
 578
 579         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 580
 581         /* mark him as being alive */
 582
 583         wsi->state = WSI_STATE_ESTABLISHED;
 584         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 585
 586         /* union transition */
 587         memset(&wsi->u, 0, sizeof wsi->u);
 588
 589         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 590
 591         /* call him back to inform him he is up */
 592
 593         wsi->protocol->callback(context, wsi,
 594                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 595                                                      wsi->user_space, NULL, 0);
 596 #ifndef LWS_NO_EXTENSIONS
 597         /*
 598          * inform all extensions, not just active ones since they
 599          * already know
 600          */
 601
 602         ext = context->extensions;
 603
 604         while (ext && ext->callback) {
 605                 v = NULL;
 606                 for (n = 0; n < wsi->count_active_extensions; n++)
 607                         if (wsi->active_extensions[n] == ext)
 608                                 v = wsi->active_extensions_user[n];
 609
 610                 ext->callback(context, ext, wsi,
 611                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 612                 ext++;
 613         }
 614 #endif
 615
 616         return 0;
 617
 618 bail3:
 619         if (wsi->c_protocol)
 620                 free(wsi->c_protocol);
 621
 622 bail2:
 623         if (wsi->c_callback) wsi->c_callback(context, wsi,
 624        LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 625                          wsi->user_space,
 626                          NULL, 0);
 627         lwsl_info("closing connection due to bail2 connection error\n");
 628         libwebsocket_close_and_free_session(context, wsi,
 629                                                  LWS_CLOSE_STATUS_PROTOCOL_ERR);
 630
 631         return 1;
 632 }
 633
 634
 635 char *
 636 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 637                 struct libwebsocket *wsi, char *pkt)
 638 {
 639         char hash[20];
 640         char key_b64[40];
 641         char *p = pkt;
 642         int n;
 643 #ifndef LWS_NO_EXTENSIONS
 644         struct libwebsocket_extension *ext;
 645         struct libwebsocket_extension *ext1;
 646         int ext_count = 0;
 647 #endif
 648         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 649                          MAX_USER_RX_BUFFER + LWS_SEND_BUFFER_POST_PADDING];
 650         static const char magic_websocket_guid[] =
 651                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 652
 653         /*
 654          * create the random key
 655          */
 656
 657         n = libwebsockets_get_random(context, hash, 16);
 658         if (n != 16) {
 659                 lwsl_err("Unable to read from random dev %s\n",
 660                                                 SYSTEM_RANDOM_FILEPATH);
 661                 free(wsi->c_path);
 662                 free(wsi->c_host);
 663                 if (wsi->c_origin)
 664                         free(wsi->c_origin);
 665                 if (wsi->c_protocol)
 666                         free(wsi->c_protocol);
 667                 libwebsocket_close_and_free_session(context, wsi,
 668                                              LWS_CLOSE_STATUS_NOSTATUS);
 669                 return NULL;
 670         }
 671
 672         lws_b64_encode_string(hash, 16, key_b64, sizeof key_b64);
 673
 674         /*
 675          * 00 example client handshake
 676          *
 677          * GET /socket.io/websocket HTTP/1.1
 678          * Upgrade: WebSocket
 679          * Connection: Upgrade
 680          * Host: 127.0.0.1:9999
 681          * Origin: http://127.0.0.1
 682          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 683          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 684          * Cookie: socketio=websocket
 685          *
 686          * (Á®Ä0¶†≥
 687          *
 688          * 04 example client handshake
 689          *
 690          * GET /chat HTTP/1.1
 691          * Host: server.example.com
 692          * Upgrade: websocket
 693          * Connection: Upgrade
 694          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 695          * Sec-WebSocket-Origin: http://example.com
 696          * Sec-WebSocket-Protocol: chat, superchat
 697          * Sec-WebSocket-Version: 4
 698          */
 699
 700         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
 701
 702         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 703                                         "Cache-Control: no-cache\x0d\x0a");
 704
 705         p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
 706         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 707                                         "Connection: Upgrade\x0d\x0a"
 708                                         "Sec-WebSocket-Key: ");
 709         strcpy(p, key_b64);
 710         p += strlen(key_b64);
 711         p += sprintf(p, "\x0d\x0a");
 712         if (wsi->c_origin) {
 713                 if (wsi->ietf_spec_revision == 13)
 714                         p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
 715                 else
 716                         p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
 717                                                          wsi->c_origin);
 718         }
 719         if (wsi->c_protocol)
 720                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 721                                                        wsi->c_protocol);
 722
 723         /* tell the server what extensions we could support */
 724
 725         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 726 #ifndef LWS_NO_EXTENSIONS
 727         ext = context->extensions;
 728         while (ext && ext->callback) {
 729
 730                 n = 0;
 731                 ext1 = context->extensions;
 732
 733                 while (ext1 && ext1->callback) {
 734                         n |= ext1->callback(context, ext1, wsi,
 735                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 736                                         NULL, (char *)ext->name, 0);
 737
 738                         ext1++;
 739                 }
 740
 741                 if (n) { /* an extension vetos us */
 742                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 743                         ext++;
 744                         continue;
 745                 }
 746
 747                 n = context->protocols[0].callback(context, wsi,
 748                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 749                                 wsi->user_space, (char *)ext->name, 0);
 750
 751                 /*
 752                  * zero return from callback means
 753                  * go ahead and allow the extension,
 754                  * it's what we get if the callback is
 755                  * unhandled
 756                  */
 757
 758                 if (n) {
 759                         ext++;
 760                         continue;
 761                 }
 762
 763                 /* apply it */
 764
 765                 if (ext_count)
 766                         *p++ = ',';
 767                 p += sprintf(p, "%s", ext->name);
 768                 ext_count++;
 769
 770                 ext++;
 771         }
 772 #endif
 773         p += sprintf(p, "\x0d\x0a");
 774
 775         if (wsi->ietf_spec_revision)
 776                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 777                                                wsi->ietf_spec_revision);
 778
 779         /* give userland a chance to append, eg, cookies */
 780
 781         context->protocols[0].callback(context, wsi,
 782                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 783                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 784
 785         p += sprintf(p, "\x0d\x0a");
 786
 787         /* prepare the expected server accept response */
 788
 789         strcpy((char *)buf, key_b64);
 790         strcpy((char *)&buf[strlen((char *)buf)], magic_websocket_guid);
 791
 792         SHA1(buf, strlen((char *)buf), (unsigned char *)hash);
 793
 794         lws_b64_encode_string(hash, 20,
 795                         wsi->u.hdr.initial_handshake_hash_base64,
 796                              sizeof wsi->u.hdr.initial_handshake_hash_base64);
 797
 798         /* done with these now */
 799
 800         free(wsi->c_path);
 801         free(wsi->c_host);
 802         if (wsi->c_origin)
 803                 free(wsi->c_origin);
 804
 805         return p;
 806 }
 807