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->mode = LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY;
 206                 libwebsocket_set_timeout(wsi,
 207                                 PENDING_TIMEOUT_AWAITING_SERVER_RESPONSE, AWAITING_TIMEOUT);
 208
 209                 break;
 210
 211         case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 212
 213                 /* handle server hung up on us */
 214
 215                 if (pollfd->revents & (POLLERR | POLLHUP)) {
 216
 217                         lwsl_debug("Server connection %p (fd=%d) dead\n",
 218                                 (void *)wsi, pollfd->fd);
 219
 220                         goto bail3;
 221                 }
 222
 223
 224                 /* interpret the server response */
 225
 226                 /*
 227                  *  HTTP/1.1 101 Switching Protocols
 228                  *  Upgrade: websocket
 229                  *  Connection: Upgrade
 230                  *  Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
 231                  *  Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
 232                  *  Sec-WebSocket-Protocol: chat
 233                  */
 234
 235                 /*
 236                  * we have to take some care here to only take from the
 237                  * socket bytewise.  The browser may (and has been seen to
 238                  * in the case that onopen() performs websocket traffic)
 239                  * coalesce both handshake response and websocket traffic
 240                  * in one packet, since at that point the connection is
 241                  * definitively ready from browser pov.
 242                  */
 243
 244                 len = 1;
 245                 while (wsi->parser_state != WSI_PARSING_COMPLETE && len > 0) {
 246 #ifdef LWS_OPENSSL_SUPPORT
 247                         if (wsi->use_ssl)
 248                                 len = SSL_read(wsi->ssl, &c, 1);
 249                          else
 250 #endif
 251                                 len = recv(wsi->sock, &c, 1, 0);
 252
 253                         libwebsocket_parse(wsi, c);
 254                 }
 255
 256                 /*
 257                  * hs may also be coming in multiple packets, there is a 5-sec
 258                  * libwebsocket timeout still active here too, so if parsing did
 259                  * not complete just wait for next packet coming in this state
 260                  */
 261
 262                 if (wsi->parser_state != WSI_PARSING_COMPLETE)
 263                         break;
 264
 265                 /*
 266                  * otherwise deal with the handshake.  If there's any
 267                  * packet traffic already arrived we'll trigger poll() again
 268                  * right away and deal with it that way
 269                  */
 270
 271                 return lws_client_interpret_server_handshake(context, wsi);
 272
 273 bail3:
 274                 if (wsi->c_protocol)
 275                         free(wsi->c_protocol);
 276                 libwebsocket_close_and_free_session(context, wsi,
 277                                                     LWS_CLOSE_STATUS_NOSTATUS);
 278                 return 0;
 279
 280         case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 281                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT\n");
 282                 break;
 283
 284         case LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD:
 285                 lwsl_ext("LWS_CONNMODE_WS_CLIENT_PENDING_CANDIDATE_CHILD\n");
 286                 break;
 287         default:
 288                 break;
 289         }
 290
 291         return 0;
 292 }
 293
 294
 295 /*
 296  * In-place str to lower case
 297  */
 298
 299 static void
 300 strtolower(char *s)
 301 {
 302         while (*s) {
 303                 *s = tolower(*s);
 304                 s++;
 305         }
 306 }
 307
 308 int
 309 lws_client_interpret_server_handshake(struct libwebsocket_context *context,
 310                 struct libwebsocket *wsi)
 311 {
 312         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 313                         MAX_BROADCAST_PAYLOAD + LWS_SEND_BUFFER_POST_PADDING];
 314         char pkt[1024];
 315         char *p = &pkt[0];
 316         const char *pc;
 317         const char *c;
 318         int more = 1;
 319         int okay = 0;
 320         char ext_name[128];
 321         struct libwebsocket_extension *ext;
 322         void *v;
 323         int len = 0;
 324         int n;
 325         static const char magic_websocket_04_masking_guid[] =
 326                                          "61AC5F19-FBBA-4540-B96F-6561F1AB40A8";
 327
 328         /*
 329          * 00 / 76 -->
 330          *
 331          * HTTP/1.1 101 WebSocket Protocol Handshake
 332          * Upgrade: WebSocket
 333          * Connection: Upgrade
 334          * Sec-WebSocket-Origin: http://127.0.0.1
 335          * Sec-WebSocket-Location: ws://127.0.0.1:9999/socket.io/websocket
 336          *
 337          * xxxxxxxxxxxxxxxx
 338          */
 339
 340         if (wsi->ietf_spec_revision == 0) {
 341                 if (!wsi->utf8_token[WSI_TOKEN_HTTP].token_len ||
 342                         !wsi->utf8_token[WSI_TOKEN_UPGRADE].token_len ||
 343                         !wsi->utf8_token[WSI_TOKEN_CHALLENGE].token_len ||
 344                         !wsi->utf8_token[WSI_TOKEN_CONNECTION].token_len ||
 345                         (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len &&
 346                         wsi->c_protocol != NULL)) {
 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             (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len &&
 401                                                     wsi->c_protocol != NULL)) {
 402                 lwsl_parser("libwebsocket_client_handshake "
 403                                         "missing required header(s)\n");
 404                 pkt[len] = '\0';
 405                 lwsl_parser("%s", pkt);
 406                 goto bail3;
 407         }
 408
 409         /*
 410          * Everything seems to be there, now take a closer look at what
 411          * is in each header
 412          */
 413
 414         strtolower(wsi->utf8_token[WSI_TOKEN_HTTP].token);
 415         if (strncmp(wsi->utf8_token[WSI_TOKEN_HTTP].token, "101", 3)) {
 416                 lwsl_warn("libwebsocket_client_handshake "
 417                                 "server sent bad HTTP response '%s'\n",
 418                                  wsi->utf8_token[WSI_TOKEN_HTTP].token);
 419                 goto bail3;
 420         }
 421
 422         strtolower(wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 423         if (strcmp(wsi->utf8_token[WSI_TOKEN_UPGRADE].token,
 424                                                          "websocket")) {
 425                 lwsl_warn("libwebsocket_client_handshake server "
 426                                 "sent bad Upgrade header '%s'\n",
 427                                   wsi->utf8_token[WSI_TOKEN_UPGRADE].token);
 428                 goto bail3;
 429         }
 430
 431         strtolower(wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 432         if (strcmp(wsi->utf8_token[WSI_TOKEN_CONNECTION].token,
 433                                                            "upgrade")) {
 434                 lwsl_warn("libwebsocket_client_handshake server "
 435                                 "sent bad Connection hdr '%s'\n",
 436                            wsi->utf8_token[WSI_TOKEN_CONNECTION].token);
 437                 goto bail3;
 438         }
 439
 440 select_protocol:
 441         pc = wsi->c_protocol;
 442         if (pc == NULL)
 443                 lwsl_parser("lws_client_interpret_server_handshake: "
 444                                                           "NULL c_protocol\n");
 445         else
 446                 lwsl_parser("lws_client_interpret_server_handshake: "
 447                                                       "cPprotocol='%s'\n", pc);
 448
 449         /*
 450          * confirm the protocol the server wants to talk was in the list
 451          * of protocols we offered
 452          */
 453
 454         if (!wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len) {
 455
 456                 lwsl_warn("lws_client_interpret_server_handshake "
 457                                                "WSI_TOKEN_PROTOCOL is null\n");
 458                 /*
 459                  * no protocol name to work from,
 460                  * default to first protocol
 461                  */
 462                 wsi->protocol = &context->protocols[0];
 463                 wsi->c_callback = wsi->protocol->callback;
 464                 free(wsi->c_protocol);
 465
 466                 goto check_extensions;
 467         }
 468
 469         while (*pc && !okay) {
 470                 if ((!strncmp(pc, wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 471                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len)) &&
 472                  (pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == ',' ||
 473                   pc[wsi->utf8_token[WSI_TOKEN_PROTOCOL].token_len] == '\0')) {
 474                         okay = 1;
 475                         continue;
 476                 }
 477                 while (*pc && *pc != ',')
 478                         pc++;
 479                 while (*pc && *pc != ' ')
 480                         pc++;
 481         }
 482
 483         /* done with him now */
 484
 485         if (wsi->c_protocol)
 486                 free(wsi->c_protocol);
 487
 488         if (!okay) {
 489                 lwsl_err("libwebsocket_client_handshake server "
 490                                         "sent bad protocol '%s'\n",
 491                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 492                 goto bail2;
 493         }
 494
 495         /*
 496          * identify the selected protocol struct and set it
 497          */
 498         n = 0;
 499         wsi->protocol = NULL;
 500         while (context->protocols[n].callback && !wsi->protocol) {  /* Stop after finding first one?? */
 501                 if (strcmp(wsi->utf8_token[WSI_TOKEN_PROTOCOL].token,
 502                                            context->protocols[n].name) == 0) {
 503                         wsi->protocol = &context->protocols[n];
 504                         wsi->c_callback = wsi->protocol->callback;
 505                 }
 506                 n++;
 507         }
 508
 509         if (wsi->protocol == NULL) {
 510                 lwsl_err("libwebsocket_client_handshake server "
 511                                 "requested protocol '%s', which we "
 512                                 "said we supported but we don't!\n",
 513                                  wsi->utf8_token[WSI_TOKEN_PROTOCOL].token);
 514                 goto bail2;
 515         }
 516
 517
 518 check_extensions:
 519
 520         /* instantiate the accepted extensions */
 521
 522         if (!wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token_len) {
 523                 lwsl_ext("no client extenstions allowed by server\n");
 524                 goto check_accept;
 525         }
 526
 527         /*
 528          * break down the list of server accepted extensions
 529          * and go through matching them or identifying bogons
 530          */
 531
 532         c = wsi->utf8_token[WSI_TOKEN_EXTENSIONS].token;
 533         n = 0;
 534         while (more) {
 535
 536                 if (*c && (*c != ',' && *c != ' ' && *c != '\t')) {
 537                         ext_name[n] = *c++;
 538                         if (n < sizeof(ext_name) - 1)
 539                                 n++;
 540                         continue;
 541                 }
 542                 ext_name[n] = '\0';
 543                 if (!*c)
 544                         more = 0;
 545                 else {
 546                         c++;
 547                         if (!n)
 548                                 continue;
 549                 }
 550
 551                 /* check we actually support it */
 552
 553                 lwsl_ext("checking client ext %s\n", ext_name);
 554
 555                 n = 0;
 556                 ext = wsi->protocol->owning_server->extensions;
 557                 while (ext && ext->callback) {
 558
 559                         if (strcmp(ext_name, ext->name)) {
 560                                 ext++;
 561                                 continue;
 562                         }
 563
 564                         n = 1;
 565
 566                         lwsl_ext("instantiating client ext %s\n", ext_name);
 567
 568                         /* instantiate the extension on this conn */
 569
 570                         wsi->active_extensions_user[
 571                                 wsi->count_active_extensions] =
 572                                          malloc(ext->per_session_data_size);
 573                         if (wsi->active_extensions_user[
 574                                 wsi->count_active_extensions] == NULL) {
 575                                 lwsl_err("Out of mem\n");
 576                                 goto bail2;
 577                         }
 578                         memset(wsi->active_extensions_user[
 579                                 wsi->count_active_extensions], 0,
 580                                                     ext->per_session_data_size);
 581                         wsi->active_extensions[
 582                                   wsi->count_active_extensions] = ext;
 583
 584                         /* allow him to construct his context */
 585
 586                         ext->callback(wsi->protocol->owning_server,
 587                                 ext, wsi,
 588                                    LWS_EXT_CALLBACK_CLIENT_CONSTRUCT,
 589                                         wsi->active_extensions_user[
 590                                          wsi->count_active_extensions],
 591                                                                    NULL, 0);
 592
 593                         wsi->count_active_extensions++;
 594
 595                         ext++;
 596                 }
 597
 598                 if (n == 0) {
 599                         lwsl_warn("Server said we should use"
 600                                   "an unknown extension '%s'!\n", ext_name);
 601                         goto bail2;
 602                 }
 603
 604                 n = 0;
 605         }
 606
 607
 608 check_accept:
 609
 610         if (wsi->ietf_spec_revision == 0) {
 611
 612                 if (memcmp(wsi->initial_handshake_hash_base64,
 613                           wsi->utf8_token[WSI_TOKEN_CHALLENGE].token, 16)) {
 614                         lwsl_warn("libwebsocket_client_handshake "
 615                                            "failed 00 challenge compare\n");
 616                                 pkt[len] = '\0';
 617                                 lwsl_warn("%s", pkt);
 618                                 goto bail2;
 619                 }
 620
 621                 goto accept_ok;
 622         }
 623
 624         /*
 625          * Confirm his accept token is the one we precomputed
 626          */
 627
 628         if (strcmp(wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 629                                   wsi->initial_handshake_hash_base64)) {
 630                 lwsl_warn("libwebsocket_client_handshake server "
 631                         "sent bad ACCEPT '%s' vs computed '%s'\n",
 632                         wsi->utf8_token[WSI_TOKEN_ACCEPT].token,
 633                                         wsi->initial_handshake_hash_base64);
 634                 goto bail2;
 635         }
 636
 637         if (wsi->ietf_spec_revision == 4) {
 638                 /*
 639                  * Calculate the 04 masking key to use when
 640                  * sending data to server
 641                  */
 642
 643                 strcpy((char *)buf, wsi->key_b64);
 644                 p = (char *)buf + strlen(wsi->key_b64);
 645                 strcpy(p, wsi->utf8_token[WSI_TOKEN_NONCE].token);
 646                 p += wsi->utf8_token[WSI_TOKEN_NONCE].token_len;
 647                 strcpy(p, magic_websocket_04_masking_guid);
 648                 SHA1(buf, strlen((char *)buf), wsi->masking_key_04);
 649         }
 650 accept_ok:
 651
 652         /* allocate the per-connection user memory (if any) */
 653         if (wsi->protocol->per_session_data_size &&
 654                                           !libwebsocket_ensure_user_space(wsi))
 655                 goto bail2;
 656
 657         /* clear his proxy connection timeout */
 658
 659         libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
 660
 661         /* mark him as being alive */
 662
 663         wsi->state = WSI_STATE_ESTABLISHED;
 664         wsi->mode = LWS_CONNMODE_WS_CLIENT;
 665
 666         lwsl_debug("handshake OK for protocol %s\n", wsi->protocol->name);
 667
 668         /* call him back to inform him he is up */
 669
 670         wsi->protocol->callback(context, wsi,
 671                                 LWS_CALLBACK_CLIENT_ESTABLISHED,
 672                                                      wsi->user_space, NULL, 0);
 673
 674         /*
 675          * inform all extensions, not just active ones since they
 676          * already know
 677          */
 678
 679         ext = context->extensions;
 680
 681         while (ext && ext->callback) {
 682                 v = NULL;
 683                 for (n = 0; n < wsi->count_active_extensions; n++)
 684                         if (wsi->active_extensions[n] == ext)
 685                                 v = wsi->active_extensions_user[n];
 686
 687                 ext->callback(context, ext, wsi,
 688                           LWS_EXT_CALLBACK_ANY_WSI_ESTABLISHED, v, NULL, 0);
 689                 ext++;
 690         }
 691
 692         return 0;
 693
 694 bail3:
 695         if (wsi->c_protocol)
 696                 free(wsi->c_protocol);
 697
 698 bail2:
 699         if (wsi->c_callback) wsi->c_callback(context, wsi,
 700        LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 701                          wsi->user_space,
 702                          NULL, 0);
 703         libwebsocket_close_and_free_session(context, wsi,
 704                                                  LWS_CLOSE_STATUS_NOSTATUS);  // But this should be LWS_CLOSE_STATUS_PROTOCOL_ERR
 705
 706         return 1;
 707 }
 708
 709 void libwebsockets_00_spaceout(char *key, int spaces, int seed)
 710 {
 711         char *p;
 712
 713         key++;
 714         while (spaces--) {
 715                 if (*key && (seed & 1))
 716                         key++;
 717                 seed >>= 1;
 718
 719                 p = key + strlen(key);
 720                 while (p >= key) {
 721                         p[1] = p[0];
 722                         p--;
 723                 }
 724                 *key++ = ' ';
 725         }
 726 }
 727
 728 void libwebsockets_00_spam(char *key, int count, int seed)
 729 {
 730         char *p;
 731
 732         key++;
 733         while (count--) {
 734
 735                 if (*key && (seed & 1))
 736                         key++;
 737                 seed >>= 1;
 738
 739                 p = key + strlen(key);
 740                 while (p >= key) {
 741                         p[1] = p[0];
 742                         p--;
 743                 }
 744                 *key++ = 0x21 + ((seed & 0xffff) % 15);
 745                 /* 4 would use it up too fast.. not like it matters */
 746                 seed >>= 1;
 747         }
 748 }
 749
 750 char *
 751 libwebsockets_generate_client_handshake(struct libwebsocket_context *context,
 752                 struct libwebsocket *wsi, char *pkt)
 753 {
 754         char hash[20];
 755         char *p = pkt;
 756         int n;
 757         struct libwebsocket_extension *ext;
 758         struct libwebsocket_extension *ext1;
 759         int ext_count = 0;
 760         unsigned char buf[LWS_SEND_BUFFER_PRE_PADDING + 1 +
 761                          MAX_BROADCAST_PAYLOAD + LWS_SEND_BUFFER_POST_PADDING];
 762         static const char magic_websocket_guid[] =
 763                                          "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
 764
 765         /*
 766          * create the random key
 767          */
 768
 769         n = libwebsockets_get_random(context, hash, 16);
 770         if (n != 16) {
 771                 lwsl_err("Unable to read from random dev %s\n",
 772                                                 SYSTEM_RANDOM_FILEPATH);
 773                 free(wsi->c_path);
 774                 free(wsi->c_host);
 775                 if (wsi->c_origin)
 776                         free(wsi->c_origin);
 777                 if (wsi->c_protocol)
 778                         free(wsi->c_protocol);
 779                 libwebsocket_close_and_free_session(context, wsi,
 780                                              LWS_CLOSE_STATUS_NOSTATUS);
 781                 return NULL;
 782         }
 783
 784         lws_b64_encode_string(hash, 16, wsi->key_b64,
 785                                                    sizeof wsi->key_b64);
 786
 787         /*
 788          * 00 example client handshake
 789          *
 790          * GET /socket.io/websocket HTTP/1.1
 791          * Upgrade: WebSocket
 792          * Connection: Upgrade
 793          * Host: 127.0.0.1:9999
 794          * Origin: http://127.0.0.1
 795          * Sec-WebSocket-Key1: 1 0 2#0W 9 89 7  92 ^
 796          * Sec-WebSocket-Key2: 7 7Y 4328 B2v[8(z1
 797          * Cookie: socketio=websocket
 798          *
 799          * (Á®Ä0¶†≥
 800          *
 801          * 04 example client handshake
 802          *
 803          * GET /chat HTTP/1.1
 804          * Host: server.example.com
 805          * Upgrade: websocket
 806          * Connection: Upgrade
 807          * Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
 808          * Sec-WebSocket-Origin: http://example.com
 809          * Sec-WebSocket-Protocol: chat, superchat
 810          * Sec-WebSocket-Version: 4
 811          */
 812
 813         p += sprintf(p, "GET %s HTTP/1.1\x0d\x0a", wsi->c_path);
 814
 815         p += sprintf(p, "Pragma: no-cache\x0d\x0a"
 816                                         "Cache-Control: no-cache\x0d\x0a");
 817
 818         if (wsi->ietf_spec_revision == 0) {
 819                 unsigned char spaces_1, spaces_2;
 820                 unsigned int max_1, max_2;
 821                 unsigned int num_1, num_2;
 822                 unsigned long product_1, product_2;
 823                 char key_1[40];
 824                 char key_2[40];
 825                 unsigned int seed;
 826                 unsigned int count;
 827                 char challenge[16];
 828
 829                 libwebsockets_get_random(context, &spaces_1, sizeof(char));
 830                 libwebsockets_get_random(context, &spaces_2, sizeof(char));
 831
 832                 spaces_1 = (spaces_1 % 12) + 1;
 833                 spaces_2 = (spaces_2 % 12) + 1;
 834
 835                 max_1 = 4294967295 / spaces_1;
 836                 max_2 = 4294967295 / spaces_2;
 837
 838                 libwebsockets_get_random(context, &num_1, sizeof(int));
 839                 libwebsockets_get_random(context, &num_2, sizeof(int));
 840
 841                 num_1 = (num_1 % max_1);
 842                 num_2 = (num_2 % max_2);
 843
 844                 challenge[0] = num_1 >> 24;
 845                 challenge[1] = num_1 >> 16;
 846                 challenge[2] = num_1 >> 8;
 847                 challenge[3] = num_1;
 848                 challenge[4] = num_2 >> 24;
 849                 challenge[5] = num_2 >> 16;
 850                 challenge[6] = num_2 >> 8;
 851                 challenge[7] = num_2;
 852
 853                 product_1 = num_1 * spaces_1;
 854                 product_2 = num_2 * spaces_2;
 855
 856                 sprintf(key_1, "%lu", product_1);
 857                 sprintf(key_2, "%lu", product_2);
 858
 859                 libwebsockets_get_random(context, &seed, sizeof(int));
 860                 libwebsockets_get_random(context, &count, sizeof(int));
 861
 862                 libwebsockets_00_spam(key_1, (count % 12) + 1, seed);
 863
 864                 libwebsockets_get_random(context, &seed, sizeof(int));
 865                 libwebsockets_get_random(context, &count, sizeof(int));
 866
 867                 libwebsockets_00_spam(key_2, (count % 12) + 1, seed);
 868
 869                 libwebsockets_get_random(context, &seed, sizeof(int));
 870
 871                 libwebsockets_00_spaceout(key_1, spaces_1, seed);
 872                 libwebsockets_00_spaceout(key_2, spaces_2, seed >> 16);
 873
 874                 p += sprintf(p, "Upgrade: WebSocket\x0d\x0a"
 875                         "Connection: Upgrade\x0d\x0aHost: %s\x0d\x0a",
 876                         wsi->c_host);
 877                 if (wsi->c_origin)
 878                         p += sprintf(p, "Origin: %s\x0d\x0a", wsi->c_origin);
 879
 880                 if (wsi->c_protocol)
 881                         p += sprintf(p, "Sec-WebSocket-Protocol: %s"
 882                                          "\x0d\x0a", wsi->c_protocol);
 883
 884                 p += sprintf(p, "Sec-WebSocket-Key1: %s\x0d\x0a", key_1);
 885                 p += sprintf(p, "Sec-WebSocket-Key2: %s\x0d\x0a", key_2);
 886
 887                 /* give userland a chance to append, eg, cookies */
 888
 889                 context->protocols[0].callback(context, wsi,
 890                         LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 891                                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 892
 893                 p += sprintf(p, "\x0d\x0a");
 894
 895                 if (libwebsockets_get_random(context, p, 8) != 8)
 896                         return NULL;
 897                 memcpy(&challenge[8], p, 8);
 898                 p += 8;
 899
 900                 /* precompute what we want to see from the server */
 901
 902                 MD5((unsigned char *)challenge, 16,
 903                    (unsigned char *)wsi->initial_handshake_hash_base64);
 904
 905                 goto issue_hdr;
 906         }
 907
 908         p += sprintf(p, "Host: %s\x0d\x0a", wsi->c_host);
 909         p += sprintf(p, "Upgrade: websocket\x0d\x0a"
 910                                         "Connection: Upgrade\x0d\x0a"
 911                                         "Sec-WebSocket-Key: ");
 912         strcpy(p, wsi->key_b64);
 913         p += strlen(wsi->key_b64);
 914         p += sprintf(p, "\x0d\x0a");
 915         if (wsi->c_origin) {
 916         if (wsi->ietf_spec_revision == 13) {
 917             p += sprintf(p, "Origin: %s\x0d\x0a",
 918                                                          wsi->c_origin);
 919         }
 920         else {
 921                     p += sprintf(p, "Sec-WebSocket-Origin: %s\x0d\x0a",
 922                                                          wsi->c_origin);
 923         }
 924     }
 925         if (wsi->c_protocol)
 926                 p += sprintf(p, "Sec-WebSocket-Protocol: %s\x0d\x0a",
 927                                                        wsi->c_protocol);
 928
 929         /* tell the server what extensions we could support */
 930
 931         p += sprintf(p, "Sec-WebSocket-Extensions: ");
 932
 933         ext = context->extensions;
 934         while (ext && ext->callback) {
 935
 936                 n = 0;
 937                 ext1 = context->extensions;
 938
 939                 while (ext1 && ext1->callback) {
 940                         n |= ext1->callback(context, ext1, wsi,
 941                                 LWS_EXT_CALLBACK_CHECK_OK_TO_PROPOSE_EXTENSION,
 942                                         NULL, (char *)ext->name, 0);
 943
 944                         ext1++;
 945                 }
 946
 947                 if (n) { /* an extension vetos us */
 948                         lwsl_ext("ext %s vetoed\n", (char *)ext->name);
 949                         ext++;
 950                         continue;
 951                 }
 952
 953                 n = context->protocols[0].callback(context, wsi,
 954                         LWS_CALLBACK_CLIENT_CONFIRM_EXTENSION_SUPPORTED,
 955                                 wsi->user_space, (char *)ext->name, 0);
 956
 957                 /*
 958                  * zero return from callback means
 959                  * go ahead and allow the extension,
 960                  * it's what we get if the callback is
 961                  * unhandled
 962                  */
 963
 964                 if (n) {
 965                         ext++;
 966                         continue;
 967                 }
 968
 969                 /* apply it */
 970
 971                 if (ext_count)
 972                         *p++ = ',';
 973                 p += sprintf(p, "%s", ext->name);
 974                 ext_count++;
 975
 976                 ext++;
 977         }
 978
 979         p += sprintf(p, "\x0d\x0a");
 980
 981         if (wsi->ietf_spec_revision)
 982                 p += sprintf(p, "Sec-WebSocket-Version: %d\x0d\x0a",
 983                                                wsi->ietf_spec_revision);
 984
 985         /* give userland a chance to append, eg, cookies */
 986
 987         context->protocols[0].callback(context, wsi,
 988                 LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER,
 989                 NULL, &p, (pkt + sizeof(pkt)) - p - 12);
 990
 991         p += sprintf(p, "\x0d\x0a");
 992
 993         /* prepare the expected server accept response */
 994
 995         strcpy((char *)buf, wsi->key_b64);
 996         strcpy((char *)&buf[strlen((char *)buf)], magic_websocket_guid);
 997
 998         SHA1(buf, strlen((char *)buf), (unsigned char *)hash);
 999
1000         lws_b64_encode_string(hash, 20,
1001                         wsi->initial_handshake_hash_base64,
1002                              sizeof wsi->initial_handshake_hash_base64);
1003
1004 issue_hdr:
1005
1006 #if 0
1007         puts(pkt);
1008 #endif
1009
1010         /* done with these now */
1011
1012         free(wsi->c_path);
1013         free(wsi->c_host);
1014         if (wsi->c_origin)
1015                 free(wsi->c_origin);
1016
1017         return p;
1018 }
1019