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                         SSL_set_bio(wsi->ssl, wsi->client_bio, wsi->client_bio);
 120
 121                         SSL_set_ex_data(wsi->ssl,
 122                                         openssl_websocket_private_data_index,
 123                                                                        context);
 124                 }
 125
 126                 if (wsi->use_ssl) {
 127                         n = SSL_connect(wsi->ssl);
 128
 129                         if (n < 0) {
 130                                 n = SSL_get_error(wsi->ssl, n);
 131
 132                                 if (n == SSL_ERROR_WANT_READ ||
 133                                         n == SSL_ERROR_WANT_WRITE) {
 134                                         /*
 135                                          * wants us to retry connect due to state of the
 136                                          * underlying ssl layer... but since it may be
 137                                          * stalled on blocked write, no incoming data may
 138                                          * arrive to trigger the retry.  Force (possibly
 139                                          * many if the SSL state persists in returning the
 140                                          * condition code, but other sockets are getting
 141                                          * serviced inbetweentimes) us to get called back
 142                                          * when writable.
 143                                          */
 144
 145                                         lwsl_info("SSL_connect -> SSL_ERROR_WANT_... retrying\n");
 146                                         libwebsocket_callback_on_writable(context, wsi);
 147
 148                                         return 0; /* no error */
 149                                 }
 150                                 n = -1;
 151                         }
 152
 153                         if (n <= 0) {
 154                                 /*
 155                                  * retry if new data comes until we
 156                                  * run into the connection timeout or win
 157                                  */
 158
 159                                 lwsl_err("SSL connect error %s\n",
 160                                         ERR_error_string(ERR_get_error(),
 161                                                                   ssl_err_buf));
 162                                 return 0;
 163                         }
 164
 165                         n = SSL_get_verify_result(wsi->ssl);
 166                         if ((n != X509_V_OK) && (
 167                                 n != X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT ||
 168                                                            wsi->use_ssl != 2)) {
 169
 170                                 lwsl_err("server's cert didn't "
 171                                                            "look good %d\n", n);
 172                                 libwebsocket_close_and_free_session(context,
 173                                                 wsi, LWS_CLOSE_STATUS_NOSTATUS);
 174                                 return 0;
 175                         }
 176                 } else
 177                         wsi->ssl = NULL;
 178         #endif
 179
 180                 p = libwebsockets_generate_client_handshake(context, wsi, p);
 181                 if (p == NULL) {
 182                         lwsl_err("Failed to generate handshake for client, closing it\n");
 183                         libwebsocket_close_and_free_session(context, wsi,
 184                                                      LWS_CLOSE_STATUS_NOSTATUS);
 185                         return 0;
 186                 }
 187
 188                 /* send our request to the server */
 189
 190         #ifdef LWS_OPENSSL_SUPPORT
 191                 if (wsi->use_ssl)
 192                         n = SSL_write(wsi->ssl, pkt, p - pkt);
 193                 else
 194         #endif
 195                         n = send(wsi->sock, pkt, p - pkt, 0);
 196
 197                 if (n < 0) {
 198                         lwsl_debug("ERROR writing to client socket\n");
 199                         libwebsocket_close_and_free_session(context, wsi,
 200                                                      LWS_CLOSE_STATUS_NOSTATUS);
 201                         return 0;
 202                 }
 203
 204                 wsi->parser_state = WSI_TOKEN_NAME_PART;
 205                 wsi->lextable_pos = 0;
 206                 wsi->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 207                 libwebsocket_set_timeout(wsi,
 208                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE, AWAITING_TIMEOUT);
 209
 210                 break;
 211
 212         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 213
 214                 /* handle server hung up on us */
 215
 216                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 217
 218                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 219                                 (void *)wsi, pollfd->fd);
 220
 221                         goto bail3;
 222                 }
 223
 224
 225                 /* interpret the server response */
 226
 227                 /*
 228                  *  HTTP/1.1 101 Switching Protocols
 229                  *  Upgrade: websocket
 230                  *  Connection: Upgrade
 231                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 232                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 233                  *  Sec-WebSocket-Protocol: chat
 234                  */
 235
 236                 /*
 237                  * we have to take some care here to only take from the
 238                  * socket bytewise.  The browser may (and has been seen to
 239                  * in the case that onopen() performs websocket traffic)
 240                  * coalesce both handshake response and websocket traffic
 241                  * in one packet, since at that point the connection is
 242                  * definitively ready from browser pov.
 243                  */
 244
 245                 len = 1;
 246                 while (wsi->parser_state != WSI_PARSING_COMPLETE && len > 0) {
 247 #ifdef LWS_OPENSSL_SUPPORT
 248                         if (wsi->use_ssl)
 249                                 len = SSL_read(wsi->ssl, &c, 1);
 250                          else
 251 #endif
 252                                 len = recv(wsi->sock, &c, 1, 0);
 253
 254                         libwebsocket_parse(wsi, c);
 255                 }
 256
 257                 /*
 258                  * hs may also be coming in multiple packets, there is a 5-sec
 259                  * libwebsocket timeout still active here too, so if parsing did
 260                  * not complete just wait for next packet coming in this state
 261                  */
 262
 263                 if (wsi->parser_state != WSI_PARSING_COMPLETE)
 264                         break;
 265
 266                 /*
 267                  * otherwise deal with the handshake.  If there's any
 268                  * packet traffic already arrived we'll trigger poll() again
 269                  * right away and deal with it that way
 270                  */
 271
 272                 return lws_client_interpret_server_handshake(context, wsi);
 273
 274 bail3:
 275                 if (wsi->c_protocol)
 276                         free(wsi->c_protocol);
 277                 libwebsocket_close_and_free_session(context, wsi,
 278                                                     LWS_CLOSE_STATUS_NOSTATUS);
 279                 return 0;
 280
 281         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 282                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 283                 break;
 284
 285         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 286                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 287                 break;
 288         default:
 289                 break;
 290         }
 291
 292         return 0;
 293 }
 294
 295
 296 /*
 297  * In-place str to lower case
 298  */
 299
 300 static void
 301 strtolower(char *s)
 302 {
 303         while (*s) {
 304                 *s = tolower(*s);
 305                 s++;
 306         }
 307 }
 308
 309 int
 310 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 311                 struct libwebsocket *wsi)
 312 {
 313         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 314                         MAX_BROADCAST_PAYLOAD + LWS_SEND_BUFFER_POST_PADDING];
 315         char pkt[1024];
 316         char *p = &pkt[0];
 317         const char *pc;
 318         const char *c;
 319         int more = 1;
 320         int okay = 0;
 321         char ext_name[128];
 322         struct libwebsocket_extension *ext;
 323         void *v;
 324         int len = 0;
 325         int n;
 326         static const char magic_websocket_04_masking_guid[] =
 327                                          "61AC5F19-FBBA-4540-B96F-6561F1AB40A8";
 328
 329         /*
 330          * 00 / 76 -->
 331          *
 332          * HTTP/1.1 101 WebSocket Protocol Handshake
 333          * Upgrade: WebSocket
 334          * Connection: Upgrade
 335          * Sec-WebSocket-Origin: http://127.0.0.1
 336          * Sec-WebSocket-Location: ws://127.0.0.1:9999/socket.io/websocket
 337          *
 338          * xxxxxxxxxxxxxxxx
 339          */
 340
 341         if (wsi->ietf_spec_revision == 0) {
 342                 if (!wsi->utf8_token[WSI_TOKEN_HTTP].token_len ||
 343                         !wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len ||
 344                         !wsi->utf8_token[WSI_TOKEN_CHALLENGE].token_len ||
 345                         !wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len
 346                 ) {
 347                         lwsl_parser("libwebsocket_client_handshake "
 348                                         "missing required header(s)\n");
 349                         pkt[len] = '\0';
 350                         lwsl_parser("%s", pkt);
 351                         goto bail3;
 352                 }
 353
 354                 strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
 355                 if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
 356                         lwsl_warn("libwebsocket_client_handshake "
 357                                 "server sent bad HTTP response '%s'\n",
 358                                 wsi->utf8_token[WSI_TOKEN_HTTP].token);
 359                         goto bail3;
 360                 }
 361
 362                 if (wsi->utf8_token[WSI_TOKEN_CHALLENGE].token_len < 16) {
 363                         lwsl_parser("libwebsocket_client_handshake "
 364                                 "challenge reply too short %d\n",
 365                                 wsi->utf8_token[
 366                                         WSI_TOKEN_CHALLENGE].token_len);
 367                         pkt[len] = '\0';
 368                         lwsl_parser("%s", pkt);
 369                         goto bail3;
 370
 371                 }
 372
 373                 goto select_protocol;
 374         }
 375
 376         /*
 377          * well, what the server sent looked reasonable for syntax.
 378          * Now let's confirm it sent all the necessary headers
 379          */
 380 #if 0
 381         lwsl_parser("WSI_TOKEN_HTTP: %d\n",
 382                                     wsi->utf8_token[WSI_TOKEN_HTTP].token_len);
 383         lwsl_parser("WSI_TOKEN_UPGRADE: %d\n",
 384                                  wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len);
 385         lwsl_parser("WSI_TOKEN_CONNECTION: %d\n",
 386                               wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len);
 387         lwsl_parser("WSI_TOKEN_ACCEPT: %d\n",
 388                                   wsi->utf8_token[WSI_TOKEN_ACCEPT].token_len);
 389         lwsl_parser("WSI_TOKEN_NONCE: %d\n",
 390                                    wsi->utf8_token[WSI_TOKEN_NONCE].token_len);
 391         lwsl_parser("WSI_TOKEN_PROTOCOL: %d\n",
 392                                 wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len);
 393 #endif
 394         if (!wsi->utf8_token[WSI_TOKEN_HTTP].token_len ||
 395             !wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len ||
 396             !wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len ||
 397             !wsi->utf8_token[WSI_TOKEN_ACCEPT].token_len ||
 398             (!wsi->utf8_token[WSI_TOKEN_NONCE].token_len &&
 399                                    wsi->ietf_spec_revision == 4)
 400         ) {
 401                 lwsl_parser("libwebsocket_client_handshake "
 402                                         "missing required header(s) revision=%d\n", wsi->ietf_spec_revision);
 403                 pkt[len] = '\0';
 404                 lwsl_parser("%s", pkt);
 405                 goto bail3;
 406         }
 407
 408         /*
 409          * Everything seems to be there, now take a closer look at what
 410          * is in each header
 411          */
 412
 413         strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
 414         if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
 415                 lwsl_warn("libwebsocket_client_handshake "
 416                                 "server sent bad HTTP response '%s'\n",
 417                                  wsi->utf8_token[WSI_TOKEN_HTTP].token);
 418                 goto bail3;
 419         }
 420
 421         strtolower(wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 422         if (strcmp(wsi->utf8_token[WSI_TOKEN_UPGRADE].token,
 423                                                          "websocket")) {
 424                 lwsl_warn("libwebsocket_client_handshake server "
 425                                 "sent bad Upgrade header '%s'\n",
 426                                   wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 427                 goto bail3;
 428         }
 429
 430         strtolower(wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 431         if (strcmp(wsi->utf8_token[WSI_TOKEN_CONNECTION].token,
 432                                                            "upgrade")) {
 433                 lwsl_warn("libwebsocket_client_handshake server "
 434                                 "sent bad Connection hdr '%s'\n",
 435                            wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 436                 goto bail3;
 437         }
 438
 439 select_protocol:
 440         pc = wsi->c_protocol;
 441         if (pc == NULL)
 442                 lwsl_parser("lws_client_interpret_server_handshake: "
 443                                                           "NULL c_protocol\n");
 444         else
 445                 lwsl_parser("lws_client_interpret_server_handshake: "
 446                                                       "cPprotocol='%s'\n", pc);
 447
 448         /*
 449          * confirm the protocol the server wants to talk was in the list
 450          * of protocols we offered
 451          */
 452
 453         if (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len) {
 454
 455                 lwsl_info("lws_client_interpret_server_handshake "
 456                                                "WSI_TOKEN_PROTOCOL is null\n");
 457                 /*
 458                  * no protocol name to work from,
 459                  * default to first protocol
 460                  */
 461                 wsi->protocol = &context->protocols[0];
 462                 wsi->c_callback = wsi->protocol->callback;
 463                 free(wsi->c_protocol);
 464
 465                 goto check_extensions;
 466         }
 467
 468         while (*pc && !okay) {
 469                 if ((!strncmp(pc, wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 470                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len)) &&
 471                  (pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == ',' ||
 472                   pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == '\0')) {
 473                         okay = 1;
 474                         continue;
 475                 }
 476                 while (*pc && *pc != ',')
 477                         pc++;
 478                 while (*pc && *pc != ' ')
 479                         pc++;
 480         }
 481
 482         /* done with him now */
 483
 484         if (wsi->c_protocol)
 485                 free(wsi->c_protocol);
 486
 487         if (!okay) {
 488                 lwsl_err("libwebsocket_client_handshake server "
 489                                         "sent bad protocol '%s'\n",
 490                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 491                 goto bail2;
 492         }
 493
 494         /*
 495          * identify the selected protocol struct and set it
 496          */
 497         n = 0;
 498         wsi->protocol = NULL;
 499         while (context->protocols[n].callback && !wsi->protocol) {  /* Stop after finding first one?? */
 500                 if (strcmp(wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 501                                            context->protocols[n].name) == 0) {
 502                         wsi->protocol = &context->protocols[n];
 503                         wsi->c_callback = wsi->protocol->callback;
 504                 }
 505                 n++;
 506         }
 507
 508         if (wsi->protocol == NULL) {
 509                 lwsl_err("libwebsocket_client_handshake server "
 510                                 "requested protocol '%s', which we "
 511                                 "said we supported but we don't!\n",
 512                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 513                 goto bail2;
 514         }
 515
 516
 517 check_extensions:
 518
 519         /* instantiate the accepted extensions */
 520
 521         if (!wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token_len) {
 522                 lwsl_ext("no client extenstions allowed by server\n");
 523                 goto check_accept;
 524         }
 525
 526         /*
 527          * break down the list of server accepted extensions
 528          * and go through matching them or identifying bogons
 529          */
 530
 531         c = wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token;
 532         n = 0;
 533         while (more) {
 534
 535                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 536                         ext_name[n] = *c++;
 537                         if (n < sizeof(ext_name) - 1)
 538                                 n++;
 539                         continue;
 540                 }
 541                 ext_name[n] = '\0';
 542                 if (!*c)
 543                         more = 0;
 544                 else {
 545                         c++;
 546                         if (!n)
 547                                 continue;
 548                 }
 549
 550                 /* check we actually support it */
 551
 552                 lwsl_ext("checking client ext %s\n", ext_name);
 553
 554                 n = 0;
 555                 ext = wsi->protocol->owning_server->extensions;
 556                 while (ext && ext->callback) {
 557
 558                         if (strcmp(ext_name, ext->name)) {
 559                                 ext++;
 560                                 continue;
 561                         }
 562
 563                         n = 1;
 564
 565                         lwsl_ext("instantiating client ext %s\n", ext_name);
 566
 567                         /* instantiate the extension on this conn */
 568
 569                         wsi->active_extensions_user[
 570                                 wsi->count_active_extensions] =
 571                                          malloc(ext->per_session_data_size);
 572                         if (wsi->active_extensions_user[
 573                                 wsi->count_active_extensions] == NULL) {
 574                                 lwsl_err("Out of mem\n");
 575                                 goto bail2;
 576                         }
 577                         memset(wsi->active_extensions_user[
 578                                 wsi->count_active_extensions], 0,
 579                                                     ext->per_session_data_size);
 580                         wsi->active_extensions[
 581                                   wsi->count_active_extensions] = ext;
 582
 583                         /* allow him to construct his context */
 584
 585                         ext->callback(wsi->protocol->owning_server,
 586                                 ext, wsi,
 587                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 588                                         wsi->active_extensions_user[
 589                                          wsi->count_active_extensions],
 590                                                                    NULL, 0);
 591
 592                         wsi->count_active_extensions++;
 593
 594                         ext++;
 595                 }
 596
 597                 if (n == 0) {
 598                         lwsl_warn("Server said we should use"
 599                                   "an unknown extension '%s'!\n", ext_name);
 600                         goto bail2;
 601                 }
 602
 603                 n = 0;
 604         }
 605
 606
 607 check_accept:
 608
 609         if (wsi->ietf_spec_revision == 0) {
 610
 611                 if (memcmp(wsi->initial_handshake_hash_base64,
 612                           wsi->utf8_token[WSI_TOKEN_CHALLENGE].token, 16)) {
 613                         lwsl_warn("libwebsocket_client_handshake "
 614                                            "failed 00 challenge compare\n");
 615                                 pkt[len] = '\0';
 616                                 lwsl_warn("%s", pkt);
 617                                 goto bail2;
 618                 }
 619
 620                 goto accept_ok;
 621         }
 622
 623         /*
 624          * Confirm his accept token is the one we precomputed
 625          */
 626
 627         if (strcmp(wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 628                                   wsi->initial_handshake_hash_base64)) {
 629                 lwsl_warn("libwebsocket_client_handshake server "
 630                         "sent bad ACCEPT '%s' vs computed '%s'\n",
 631                         wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 632                                         wsi->initial_handshake_hash_base64);
 633                 goto bail2;
 634         }
 635
 636         if (wsi->ietf_spec_revision == 4) {
 637                 /*
 638                  * Calculate the 04 masking key to use when
 639                  * sending data to server
 640                  */
 641
 642                 strcpy((char *)buf, wsi->key_b64);
 643                 p = (char *)buf + strlen(wsi->key_b64);
 644                 strcpy(p, wsi->utf8_token[WSI_TOKEN_NONCE].token);
 645                 p += wsi->utf8_token[WSI_TOKEN_NONCE].token_len;
 646                 strcpy(p, magic_websocket_04_masking_guid);
 647                 SHA1(buf, strlen((char *)buf), wsi->masking_key_04);
 648         }
 649 accept_ok:
 650
 651         /* allocate the per-connection user memory (if any) */
 652         if (wsi->protocol->per_session_data_size &&
 653                                           !libwebsocket_ensure_user_space(wsi))
 654                 goto bail2;
 655
 656         /* clear his proxy connection timeout */
 657
 658         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 659
 660         /* mark him as being alive */
 661
 662         wsi->state = WSI_STATE_ESTABLISHED;
 663         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 664
 665         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 666
 667         /* call him back to inform him he is up */
 668
 669         wsi->protocol->callback(context, wsi,
 670                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 671                                                      wsi->user_space, NULL, 0);
 672
 673         /*
 674          * inform all extensions, not just active ones since they
 675          * already know
 676          */
 677
 678         ext = context->extensions;
 679
 680         while (ext && ext->callback) {
 681                 v = NULL;
 682                 for (n = 0; n < wsi->count_active_extensions; n++)
 683                         if (wsi->active_extensions[n] == ext)
 684                                 v = wsi->active_extensions_user[n];
 685
 686                 ext->callback(context, ext, wsi,
 687                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 688                 ext++;
 689         }
 690
 691         return 0;
 692
 693 bail3:
 694         if (wsi->c_protocol)
 695                 free(wsi->c_protocol);
 696
 697 bail2:
 698         if (wsi->c_callback) wsi->c_callback(context, wsi,
 699        LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 700                          wsi->user_space,
 701                          NULL, 0);
 702         libwebsocket_close_and_free_session(context, wsi,
 703                                                  LWS_CLOSE_STATUS_NOSTATUS);  // But this should be LWS_CLOSE_STATUS_PROTOCOL_ERR
 704
 705         return 1;
 706 }
 707
 708 void libwebsockets_00_spaceout(char *key, int spaces, int seed)
 709 {
 710         char *p;
 711
 712         key++;
 713         while (spaces--) {
 714                 if (*key && (seed & 1))
 715                         key++;
 716                 seed >>= 1;
 717
 718                 p = key + strlen(key);
 719                 while (p >= key) {
 720                         p[1] = p[0];
 721                         p--;
 722                 }
 723                 *key++ = ' ';
 724         }
 725 }
 726
 727 void libwebsockets_00_spam(char *key, int count, int seed)
 728 {
 729         char *p;
 730
 731         key++;
 732         while (count--) {
 733
 734                 if (*key && (seed & 1))
 735                         key++;
 736                 seed >>= 1;
 737
 738                 p = key + strlen(key);
 739                 while (p >= key) {
 740                         p[1] = p[0];
 741                         p--;
 742                 }
 743                 *key++ = 0x21 + ((seed & 0xffff) % 15);
 744                 /* 4 would use it up too fast.. not like it matters */
 745                 seed >>= 1;
 746         }
 747 }
 748
 749 char *
 750 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 751                 struct libwebsocket *wsi, char *pkt)
 752 {
 753         char hash[20];
 754         char *p = pkt;
 755         int n;
 756         struct libwebsocket_extension *ext;
 757         struct libwebsocket_extension *ext1;
 758         int ext_count = 0;
 759         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 760                          MAX_BROADCAST_PAYLOAD + LWS_SEND_BUFFER_POST_PADDING];
 761         static const char magic_websocket_guid[] =
 762                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 763
 764         /*
 765          * create the random key
 766          */
 767
 768         n = libwebsockets_get_random(context, hash, 16);
 769         if (n != 16) {
 770                 lwsl_err("Unable to read from random dev %s\n",
 771                                                 SYSTEM_RANDOM_FILEPATH);
 772                 free(wsi->c_path);
 773                 free(wsi->c_host);
 774                 if (wsi->c_origin)
 775                         free(wsi->c_origin);
 776                 if (wsi->c_protocol)
 777                         free(wsi->c_protocol);
 778                 libwebsocket_close_and_free_session(context, wsi,
 779                                              LWS_CLOSE_STATUS_NOSTATUS);
 780                 return NULL;
 781         }
 782
 783         lws_b64_encode_string(hash, 16, wsi->key_b64,
 784                                                    sizeof wsi->key_b64);
 785
 786         /*
 787          * 00 example client handshake
 788          *
 789          * GET /socket.io/websocket HTTP/1.1
 790          * Upgrade: WebSocket
 791          * Connection: Upgrade
 792          * Host: 127.0.0.1:9999
 793          * Origin: http://127.0.0.1
 794          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 795          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 796          * Cookie: socketio=websocket
 797          *
 798          * (Á®Ä0¶†≥
 799          *
 800          * 04 example client handshake
 801          *
 802          * GET /chat HTTP/1.1
 803          * Host: server.example.com
 804          * Upgrade: websocket
 805          * Connection: Upgrade
 806          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 807          * Sec-WebSocket-Origin: http://example.com
 808          * Sec-WebSocket-Protocol: chat, superchat
 809          * Sec-WebSocket-Version: 4
 810          */
 811
 812         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
 813
 814         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 815                                         "Cache-Control: no-cache\x0d\x0a");
 816
 817         if (wsi->ietf_spec_revision == 0) {
 818                 unsigned char spaces_1, spaces_2;
 819                 unsigned int max_1, max_2;
 820                 unsigned int num_1, num_2;
 821                 unsigned long product_1, product_2;
 822                 char key_1[40];
 823                 char key_2[40];
 824                 unsigned int seed;
 825                 unsigned int count;
 826                 char challenge[16];
 827
 828                 libwebsockets_get_random(context, &spaces_1, sizeof(char));
 829                 libwebsockets_get_random(context, &spaces_2, sizeof(char));
 830
 831                 spaces_1 = (spaces_1 % 12) + 1;
 832                 spaces_2 = (spaces_2 % 12) + 1;
 833
 834                 max_1 = 4294967295 / spaces_1;
 835                 max_2 = 4294967295 / spaces_2;
 836
 837                 libwebsockets_get_random(context, &num_1, sizeof(int));
 838                 libwebsockets_get_random(context, &num_2, sizeof(int));
 839
 840                 num_1 = (num_1 % max_1);
 841                 num_2 = (num_2 % max_2);
 842
 843                 challenge[0] = num_1 >> 24;
 844                 challenge[1] = num_1 >> 16;
 845                 challenge[2] = num_1 >> 8;
 846                 challenge[3] = num_1;
 847                 challenge[4] = num_2 >> 24;
 848                 challenge[5] = num_2 >> 16;
 849                 challenge[6] = num_2 >> 8;
 850                 challenge[7] = num_2;
 851
 852                 product_1 = num_1 * spaces_1;
 853                 product_2 = num_2 * spaces_2;
 854
 855                 sprintf(key_1, "%lu", product_1);
 856                 sprintf(key_2, "%lu", product_2);
 857
 858                 libwebsockets_get_random(context, &seed, sizeof(int));
 859                 libwebsockets_get_random(context, &count, sizeof(int));
 860
 861                 libwebsockets_00_spam(key_1, (count % 12) + 1, seed);
 862
 863                 libwebsockets_get_random(context, &seed, sizeof(int));
 864                 libwebsockets_get_random(context, &count, sizeof(int));
 865
 866                 libwebsockets_00_spam(key_2, (count % 12) + 1, seed);
 867
 868                 libwebsockets_get_random(context, &seed, sizeof(int));
 869
 870                 libwebsockets_00_spaceout(key_1, spaces_1, seed);
 871                 libwebsockets_00_spaceout(key_2, spaces_2, seed >> 16);
 872
 873                 p += sprintf(p, "Upgrade: WebSocket\x0d\x0a"
 874                         "Connection: Upgrade\x0d\x0aHost: %s\x0d\x0a",
 875                         wsi->c_host);
 876                 if (wsi->c_origin)
 877                         p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
 878
 879                 if (wsi->c_protocol)
 880                         p += sprintf(p, "Sec-WebSocket-Protocol: %s"
 881                                          "\x0d\x0a", wsi->c_protocol);
 882
 883                 p += sprintf(p, "Sec-WebSocket-Key1: %s\x0d\x0a", key_1);
 884                 p += sprintf(p, "Sec-WebSocket-Key2: %s\x0d\x0a", key_2);
 885
 886                 /* give userland a chance to append, eg, cookies */
 887
 888                 context->protocols[0].callback(context, wsi,
 889                         LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 890                                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 891
 892                 p += sprintf(p, "\x0d\x0a");
 893
 894                 if (libwebsockets_get_random(context, p, 8) != 8)
 895                         return NULL;
 896                 memcpy(&challenge[8], p, 8);
 897                 p += 8;
 898
 899                 /* precompute what we want to see from the server */
 900
 901                 MD5((unsigned char *)challenge, 16,
 902                    (unsigned char *)wsi->initial_handshake_hash_base64);
 903
 904                 goto issue_hdr;
 905         }
 906
 907         p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
 908         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 909                                         "Connection: Upgrade\x0d\x0a"
 910                                         "Sec-WebSocket-Key: ");
 911         strcpy(p, wsi->key_b64);
 912         p += strlen(wsi->key_b64);
 913         p += sprintf(p, "\x0d\x0a");
 914         if (wsi->c_origin) {
 915         if (wsi->ietf_spec_revision == 13) {
 916             p += sprintf(p, "Origin: %s\x0d\x0a",
 917                                                          wsi->c_origin);
 918         }
 919         else {
 920                     p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
 921                                                          wsi->c_origin);
 922         }
 923     }
 924         if (wsi->c_protocol)
 925                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 926                                                        wsi->c_protocol);
 927
 928         /* tell the server what extensions we could support */
 929
 930         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 931
 932         ext = context->extensions;
 933         while (ext && ext->callback) {
 934
 935                 n = 0;
 936                 ext1 = context->extensions;
 937
 938                 while (ext1 && ext1->callback) {
 939                         n |= ext1->callback(context, ext1, wsi,
 940                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 941                                         NULL, (char *)ext->name, 0);
 942
 943                         ext1++;
 944                 }
 945
 946                 if (n) { /* an extension vetos us */
 947                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 948                         ext++;
 949                         continue;
 950                 }
 951
 952                 n = context->protocols[0].callback(context, wsi,
 953                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 954                                 wsi->user_space, (char *)ext->name, 0);
 955
 956                 /*
 957                  * zero return from callback means
 958                  * go ahead and allow the extension,
 959                  * it's what we get if the callback is
 960                  * unhandled
 961                  */
 962
 963                 if (n) {
 964                         ext++;
 965                         continue;
 966                 }
 967
 968                 /* apply it */
 969
 970                 if (ext_count)
 971                         *p++ = ',';
 972                 p += sprintf(p, "%s", ext->name);
 973                 ext_count++;
 974
 975                 ext++;
 976         }
 977
 978         p += sprintf(p, "\x0d\x0a");
 979
 980         if (wsi->ietf_spec_revision)
 981                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 982                                                wsi->ietf_spec_revision);
 983
 984         /* give userland a chance to append, eg, cookies */
 985
 986         context->protocols[0].callback(context, wsi,
 987                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 988                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 989
 990         p += sprintf(p, "\x0d\x0a");
 991
 992         /* prepare the expected server accept response */
 993
 994         strcpy((char *)buf, wsi->key_b64);
 995         strcpy((char *)&buf[strlen((char *)buf)], magic_websocket_guid);
 996
 997         SHA1(buf, strlen((char *)buf), (unsigned char *)hash);
 998
 999         lws_b64_encode_string(hash, 20,
1000                         wsi->initial_handshake_hash_base64,
1001                              sizeof wsi->initial_handshake_hash_base64);
1002
1003 issue_hdr:
1004
1005 #if 0
1006         puts(pkt);
1007 #endif
1008
1009         /* done with these now */
1010
1011         free(wsi->c_path);
1012         free(wsi->c_host);
1013         if (wsi->c_origin)
1014                 free(wsi->c_origin);
1015
1016         return p;
1017 }
1018