lib/handshake.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 /*
  25  * -04 of the protocol (actually the 80th version) has a radically different
  26  * handshake.  The 04 spec gives the following idea
  27  *
  28  *    The handshake from the client looks as follows:
  29  *
  30  *      GET /chat HTTP/1.1
  31  *      Host: server.example.com
  32  *      Upgrade: websocket
  33  *      Connection: Upgrade
  34  *      Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
  35  *      Sec-WebSocket-Origin: http://example.com
  36  *      Sec-WebSocket-Protocol: chat, superchat
  37  *      Sec-WebSocket-Version: 4
  38  *
  39  *  The handshake from the server looks as follows:
  40  *
  41  *       HTTP/1.1 101 Switching Protocols
  42  *       Upgrade: websocket
  43  *       Connection: Upgrade
  44  *       Sec-WebSocket-Accept: me89jWimTRKTWwrS3aRrL53YZSo=
  45  *       Sec-WebSocket-Nonce: AQIDBAUGBwgJCgsMDQ4PEC==
  46  *       Sec-WebSocket-Protocol: chat
  47  */
  48
  49 /*
  50  * We have to take care about parsing because the headers may be split
  51  * into multiple fragments.  They may contain unknown headers with arbitrary
  52  * argument lengths.  So, we parse using a single-character at a time state
  53  * machine that is completely independent of packet size.
  54  */
  55
  56 LWS_VISIBLE int
  57 libwebsocket_read(struct libwebsocket_context *context,
  58                      struct libwebsocket *wsi, unsigned char *buf, size_t len)
  59 {
  60         size_t n;
  61         struct allocated_headers *ah;
  62         char *uri_ptr = NULL;
  63         int uri_len = 0;
  64         char content_length_str[32];
  65
  66         switch (wsi->state) {
  67
  68         case WSI_STATE_HTTP_BODY:
  69 http_postbody:
  70                 while (len--) {
  71
  72                         if (wsi->u.http.content_length_seen >= wsi->u.http.content_length)
  73                                 break;
  74
  75                         wsi->u.http.post_buffer[wsi->u.http.body_index++] = *buf++;
  76                         wsi->u.http.content_length_seen++;
  77                         if (wsi->u.http.body_index !=
  78                                         wsi->protocol->rx_buffer_size &&
  79                             wsi->u.http.content_length_seen != wsi->u.http.content_length)
  80                                 continue;
  81
  82                         if (wsi->protocol->callback) {
  83                                 n = wsi->protocol->callback(
  84                                         wsi->protocol->owning_server, wsi,
  85                                             LWS_CALLBACK_HTTP_BODY,
  86                                             wsi->user_space, wsi->u.http.post_buffer,
  87                                                         wsi->u.http.body_index);
  88                                 wsi->u.http.body_index = 0;
  89                                 if (n)
  90                                         goto bail;
  91                         }
  92
  93                         if (wsi->u.http.content_length_seen == wsi->u.http.content_length) {
  94                                 /* he sent the content in time */
  95                                 libwebsocket_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
  96                                 n = wsi->protocol->callback(
  97                                         wsi->protocol->owning_server, wsi,
  98                                             LWS_CALLBACK_HTTP_BODY_COMPLETION,
  99                                             wsi->user_space, NULL, 0);
 100                                 wsi->u.http.body_index = 0;
 101                                 if (n)
 102                                         goto bail;
 103                         }
 104
 105                 }
 106
 107                 /*
 108                  * we need to spill here so everything is seen in the case
 109                  * there is no content-length
 110                  */
 111                 if (wsi->u.http.body_index && wsi->protocol->callback) {
 112                         n = wsi->protocol->callback(
 113                                 wsi->protocol->owning_server, wsi,
 114                                     LWS_CALLBACK_HTTP_BODY,
 115                                     wsi->user_space, wsi->u.http.post_buffer,
 116                                                 wsi->u.http.body_index);
 117                         wsi->u.http.body_index = 0;
 118                         if (n)
 119                                 goto bail;
 120                 }
 121                 break;
 122
 123         case WSI_STATE_HTTP_ISSUING_FILE:
 124         case WSI_STATE_HTTP:
 125                 wsi->state = WSI_STATE_HTTP_HEADERS;
 126                 wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 127                 wsi->u.hdr.lextable_pos = 0;
 128                 /* fallthru */
 129         case WSI_STATE_HTTP_HEADERS:
 130
 131                 lwsl_parser("issuing %d bytes to parser\n", (int)len);
 132
 133 #ifndef LWS_NO_CLIENT
 134                 switch (wsi->mode) {
 135                 case LWS_CONNMODE_WS_CLIENT_WAITING_PROXY_REPLY:
 136                 case LWS_CONNMODE_WS_CLIENT_ISSUE_HANDSHAKE:
 137                 case LWS_CONNMODE_WS_CLIENT_WAITING_SERVER_REPLY:
 138                 case LWS_CONNMODE_WS_CLIENT_WAITING_EXTENSION_CONNECT:
 139                 case LWS_CONNMODE_WS_CLIENT:
 140                         for (n = 0; n < len; n++)
 141                                 if (libwebsocket_client_rx_sm(wsi, *buf++)) {
 142                                         lwsl_info("client_rx_sm failed\n");
 143                                         goto bail;
 144                                 }
 145                         return 0;
 146                 default:
 147                         break;
 148                 }
 149 #endif
 150 #ifndef LWS_NO_SERVER
 151                 /* LWS_CONNMODE_WS_SERVING */
 152
 153                 while (len--) {
 154                         if (libwebsocket_parse(wsi, *buf++)) {
 155                                 lwsl_info("libwebsocket_parse failed\n");
 156                                 goto bail_nuke_ah;
 157                         }
 158
 159                         if (wsi->u.hdr.parser_state != WSI_PARSING_COMPLETE)
 160                                 continue;
 161
 162                         lwsl_parser("libwebsocket_parse sees parsing complete\n");
 163
 164                         wsi->mode = LWS_CONNMODE_PRE_WS_SERVING_ACCEPT;
 165
 166                         /* is this websocket protocol or normal http 1.0? */
 167
 168                         if (!lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE) ||
 169                                      !lws_hdr_total_length(wsi, WSI_TOKEN_CONNECTION)) {
 170
 171                                 /* it's not websocket.... shall we accept it as http? */
 172
 173                                 if (!lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI) &&
 174                                     !lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI)) {
 175                                         lwsl_warn("Missing URI in HTTP request\n");
 176                                         goto bail_nuke_ah;
 177                                 }
 178
 179                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI) &&
 180                                     lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI)) {
 181                                         lwsl_warn("GET and POST methods?\n");
 182                                         goto bail_nuke_ah;
 183                                 }
 184
 185                                 if (libwebsocket_ensure_user_space(wsi))
 186                                         goto bail_nuke_ah;
 187
 188                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI)) {
 189                                         uri_ptr = lws_hdr_simple_ptr(wsi, WSI_TOKEN_GET_URI);
 190                                         uri_len = lws_hdr_total_length(wsi, WSI_TOKEN_GET_URI);
 191                                         lwsl_info("HTTP GET request for '%s'\n",
 192                                             lws_hdr_simple_ptr(wsi, WSI_TOKEN_GET_URI));
 193
 194                                 }
 195                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI)) {
 196                                         lwsl_info("HTTP POST request for '%s'\n",
 197                                            lws_hdr_simple_ptr(wsi, WSI_TOKEN_POST_URI));
 198                                         uri_ptr = lws_hdr_simple_ptr(wsi, WSI_TOKEN_POST_URI);
 199                                         uri_len = lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI);
 200                                 }
 201
 202                                 /*
 203                                  * Hm we still need the headers so the
 204                                  * callback can look at leaders like the URI, but we
 205                                  * need to transition to http union state.... hold a
 206                                  * copy of u.hdr.ah and deallocate afterwards
 207                                  */
 208                                 ah = wsi->u.hdr.ah;
 209
 210                                 /* union transition */
 211                                 memset(&wsi->u, 0, sizeof(wsi->u));
 212                                 wsi->mode = LWS_CONNMODE_HTTP_SERVING_ACCEPTED;
 213                                 wsi->state = WSI_STATE_HTTP;
 214                                 wsi->u.http.fd = -1;
 215
 216                                 /* expose it at the same offset as u.hdr */
 217                                 wsi->u.http.ah = ah;
 218
 219                                 /* HTTP header had a content length? */
 220
 221                                 wsi->u.http.content_length = 0;
 222                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI))
 223                                         wsi->u.http.content_length = 100 * 1024 * 1024;
 224
 225                                 if (lws_hdr_total_length(wsi, WSI_TOKEN_HTTP_CONTENT_LENGTH)) {
 226                                         lws_hdr_copy(wsi, content_length_str,
 227                                                         sizeof(content_length_str) - 1,
 228                                                                         WSI_TOKEN_HTTP_CONTENT_LENGTH);
 229                                         wsi->u.http.content_length = atoi(content_length_str);
 230                                 }
 231
 232                                 if (wsi->u.http.content_length > 0) {
 233                                         wsi->u.http.body_index = 0;
 234                                         wsi->u.http.post_buffer = malloc(wsi->protocol->rx_buffer_size);
 235                                         if (!wsi->u.http.post_buffer) {
 236                                                 lwsl_err("Unable to allocate post buffer\n");
 237                                                 n = -1;
 238                                                 goto leave;
 239                                         }
 240                                 }
 241
 242                                 n = 0;
 243                                 if (wsi->protocol->callback)
 244                                         n = wsi->protocol->callback(context, wsi,
 245                                                 LWS_CALLBACK_FILTER_HTTP_CONNECTION,
 246                                                      wsi->user_space, uri_ptr, uri_len);
 247
 248                                 if (!n && wsi->protocol->callback)
 249                                         n = wsi->protocol->callback(context, wsi,
 250                                             LWS_CALLBACK_HTTP,
 251                                             wsi->user_space, uri_ptr, uri_len);
 252
 253 leave:
 254                                 /* now drop the header info we kept a pointer to */
 255                                 if (ah)
 256                                         free(ah);
 257                                 /* not possible to continue to use past here */
 258                                 wsi->u.http.ah = NULL;
 259
 260                                 if (n) {
 261                                         lwsl_info("LWS_CALLBACK_HTTP closing\n");
 262                                         goto bail; /* struct ah ptr already nuked */
 263                                 }
 264
 265                                 /*
 266                                  * if there is content supposed to be coming,
 267                                  * put a timeout on it having arrived
 268                                  */
 269                                 libwebsocket_set_timeout(wsi,
 270                                         PENDING_TIMEOUT_HTTP_CONTENT,
 271                                                               AWAITING_TIMEOUT);
 272
 273                                 /*
 274                                  * deal with anything else as body, whether
 275                                  * there was a content-length or not
 276                                  */
 277
 278                                 wsi->state = WSI_STATE_HTTP_BODY;
 279                                 goto http_postbody;
 280                         }
 281
 282                         if (!wsi->protocol)
 283                                 lwsl_err("NULL protocol at libwebsocket_read\n");
 284
 285                         /*
 286                          * It's websocket
 287                          *
 288                          * Make sure user side is happy about protocol
 289                          */
 290
 291                         while (wsi->protocol->callback) {
 292
 293                                 if (!lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL)) {
 294                                         if (wsi->protocol->name == NULL)
 295                                                 break;
 296                                 } else
 297                                         if (wsi->protocol->name && strcmp(
 298                                                 lws_hdr_simple_ptr(wsi,
 299                                                         WSI_TOKEN_PROTOCOL),
 300                                                               wsi->protocol->name) == 0)
 301                                                 break;
 302
 303                                 wsi->protocol++;
 304                         }
 305
 306                         /* we didn't find a protocol he wanted? */
 307
 308                         if (wsi->protocol->callback == NULL) {
 309                                 if (lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL) ==
 310                                                                                  NULL) {
 311                                         lwsl_info("no protocol -> prot 0 handler\n");
 312                                         wsi->protocol = &context->protocols[0];
 313                                 } else {
 314                                         lwsl_err("Req protocol %s not supported\n",
 315                                            lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL));
 316                                         goto bail_nuke_ah;
 317                                 }
 318                         }
 319
 320                         /* allocate wsi->user storage */
 321                         if (libwebsocket_ensure_user_space(wsi))
 322                                 goto bail_nuke_ah;
 323
 324                         /*
 325                          * Give the user code a chance to study the request and
 326                          * have the opportunity to deny it
 327                          */
 328
 329                         if ((wsi->protocol->callback)(wsi->protocol->owning_server, wsi,
 330                                         LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION,
 331                                         wsi->user_space,
 332                                       lws_hdr_simple_ptr(wsi, WSI_TOKEN_PROTOCOL), 0)) {
 333                                 lwsl_warn("User code denied connection\n");
 334                                 goto bail_nuke_ah;
 335                         }
 336
 337
 338                         /*
 339                          * Perform the handshake according to the protocol version the
 340                          * client announced
 341                          */
 342
 343                         switch (wsi->ietf_spec_revision) {
 344                         case 13:
 345                                 lwsl_parser("lws_parse calling handshake_04\n");
 346                                 if (handshake_0405(context, wsi)) {
 347                                         lwsl_info("hs0405 has failed the connection\n");
 348                                         goto bail_nuke_ah;
 349                                 }
 350                                 break;
 351
 352                         default:
 353                                 lwsl_warn("Unknown client spec version %d\n",
 354                                                                wsi->ietf_spec_revision);
 355                                 goto bail_nuke_ah;
 356                         }
 357
 358                         /* drop the header info -- no bail_nuke_ah after this */
 359
 360                         if (wsi->u.hdr.ah)
 361                                 free(wsi->u.hdr.ah);
 362
 363                         wsi->mode = LWS_CONNMODE_WS_SERVING;
 364
 365                         /* union transition */
 366                         memset(&wsi->u, 0, sizeof(wsi->u));
 367                         wsi->u.ws.rxflow_change_to = LWS_RXFLOW_ALLOW;
 368
 369                         /*
 370                          * create the frame buffer for this connection according to the
 371                          * size mentioned in the protocol definition.  If 0 there, use
 372                          * a big default for compatibility
 373                          */
 374
 375                         n = wsi->protocol->rx_buffer_size;
 376                         if (!n)
 377                                 n = LWS_MAX_SOCKET_IO_BUF;
 378                         n += LWS_SEND_BUFFER_PRE_PADDING + LWS_SEND_BUFFER_POST_PADDING;
 379                         wsi->u.ws.rx_user_buffer = malloc(n);
 380                         if (!wsi->u.ws.rx_user_buffer) {
 381                                 lwsl_err("Out of Mem allocating rx buffer %d\n", n);
 382                                 goto bail;
 383                         }
 384                         lwsl_info("Allocating RX buffer %d\n", n);
 385
 386                         if (setsockopt(wsi->sock, SOL_SOCKET, SO_SNDBUF,  &n, sizeof n)) {
 387                                 lwsl_warn("Failed to set SNDBUF to %d", n);
 388                                 goto bail;
 389                         }
 390
 391                         lwsl_parser("accepted v%02d connection\n",
 392                                                                wsi->ietf_spec_revision);
 393 #endif
 394                 } /* while all chars are handled */
 395                 break;
 396
 397         case WSI_STATE_AWAITING_CLOSE_ACK:
 398         case WSI_STATE_ESTABLISHED:
 399 #ifndef LWS_NO_CLIENT
 400                 switch (wsi->mode) {
 401                 case LWS_CONNMODE_WS_CLIENT:
 402                         for (n = 0; n < len; n++)
 403                                 if (libwebsocket_client_rx_sm(
 404                                                              wsi, *buf++) < 0) {
 405                                         lwsl_info("client rx has bailed\n");
 406                                         goto bail;
 407                                 }
 408
 409                         return 0;
 410                 default:
 411                         break;
 412                 }
 413 #endif
 414 #ifndef LWS_NO_SERVER
 415                 /* LWS_CONNMODE_WS_SERVING */
 416
 417                 if (libwebsocket_interpret_incoming_packet(wsi, buf, len) < 0) {
 418                         lwsl_info("interpret_incoming_packet has bailed\n");
 419                         goto bail;
 420                 }
 421 #endif
 422                 break;
 423         default:
 424                 lwsl_err("libwebsocket_read: Unhandled state\n");
 425                 break;
 426         }
 427
 428         return 0;
 429
 430 bail_nuke_ah:
 431         /* drop the header info */
 432         if (wsi->u.hdr.ah)
 433                 free(wsi->u.hdr.ah);
 434
 435 bail:
 436         lwsl_info("closing connection at libwebsocket_read bail:\n");
 437
 438         libwebsocket_close_and_free_session(context, wsi,
 439                                                      LWS_CLOSE_STATUS_NOSTATUS);
 440
 441         return -1;
 442 }