lib/parsers.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 unsigned char lextable[] = {
  25         #include "lextable.h"
  26 };
  27
  28 #define FAIL_CHAR 0x08
  29
  30 int lextable_decode(int pos, char c)
  31 {
  32
  33         c = tolower(c);
  34
  35         while (1) {
  36                 if (lextable[pos] & (1 << 7)) { /* 1-byte, fail on mismatch */
  37                         if ((lextable[pos] & 0x7f) != c)
  38                                 return -1;
  39                         /* fall thru */
  40                         pos++;
  41                         if (lextable[pos] == FAIL_CHAR)
  42                                 return -1;
  43                         return pos;
  44                 }
  45                 /* b7 = 0, end or 3-byte */
  46                 if (lextable[pos] < FAIL_CHAR) /* terminal marker */
  47                         return pos;
  48
  49                 if (lextable[pos] == c) /* goto */
  50                         return pos + (lextable[pos + 1]) +
  51                                                 (lextable[pos + 2] << 8);
  52                 /* fall thru goto */
  53                 pos += 3;
  54                 /* continue */
  55         }
  56 }
  57
  58 int lws_allocate_header_table(struct libwebsocket *wsi)
  59 {
  60         wsi->u.hdr.ah = malloc(sizeof(*wsi->u.hdr.ah));
  61         if (wsi->u.hdr.ah == NULL) {
  62                 lwsl_err("Out of memory\n");
  63                 return -1;
  64         }
  65         memset(wsi->u.hdr.ah->frag_index, 0, sizeof(wsi->u.hdr.ah->frag_index));
  66         wsi->u.hdr.ah->next_frag_index = 0;
  67         wsi->u.hdr.ah->pos = 0;
  68
  69         return 0;
  70 }
  71
  72 LWS_VISIBLE int lws_hdr_total_length(struct libwebsocket *wsi, enum lws_token_indexes h)
  73 {
  74         int n;
  75         int len = 0;
  76
  77         n = wsi->u.hdr.ah->frag_index[h];
  78         if (!n)
  79                 return 0;
  80         do {
  81                 len += wsi->u.hdr.ah->frags[n].len;
  82                 n = wsi->u.hdr.ah->frags[n].next_frag_index;
  83         } while (n);
  84
  85         return len;
  86 }
  87
  88 LWS_VISIBLE int lws_hdr_copy(struct libwebsocket *wsi, char *dest, int len,
  89                                                 enum lws_token_indexes h)
  90 {
  91         int toklen = lws_hdr_total_length(wsi, h);
  92         int n;
  93
  94         if (toklen >= len)
  95                 return -1;
  96
  97         n = wsi->u.hdr.ah->frag_index[h];
  98         if (!n)
  99                 return 0;
 100
 101         do {
 102                 strcpy(dest,
 103                         &wsi->u.hdr.ah->data[wsi->u.hdr.ah->frags[n].offset]);
 104                 dest += wsi->u.hdr.ah->frags[n].len;
 105                 n = wsi->u.hdr.ah->frags[n].next_frag_index;
 106         } while (n);
 107
 108         return toklen;
 109 }
 110
 111 char *lws_hdr_simple_ptr(struct libwebsocket *wsi, enum lws_token_indexes h)
 112 {
 113         int n;
 114
 115         n = wsi->u.hdr.ah->frag_index[h];
 116         if (!n)
 117                 return NULL;
 118
 119         return &wsi->u.hdr.ah->data[wsi->u.hdr.ah->frags[n].offset];
 120 }
 121
 122 int lws_hdr_simple_create(struct libwebsocket *wsi,
 123                                 enum lws_token_indexes h, const char *s)
 124 {
 125         wsi->u.hdr.ah->next_frag_index++;
 126         if (wsi->u.hdr.ah->next_frag_index ==
 127                sizeof(wsi->u.hdr.ah->frags) / sizeof(wsi->u.hdr.ah->frags[0])) {
 128                 lwsl_warn("More hdr frags than we can deal with, dropping\n");
 129                 return -1;
 130         }
 131
 132         wsi->u.hdr.ah->frag_index[h] = wsi->u.hdr.ah->next_frag_index;
 133
 134         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].offset =
 135                                                              wsi->u.hdr.ah->pos;
 136         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len = 0;
 137         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].next_frag_index =
 138                                                                               0;
 139
 140         do {
 141                 if (wsi->u.hdr.ah->pos == sizeof(wsi->u.hdr.ah->data)) {
 142                         lwsl_err("Ran out of header data space\n");
 143                         return -1;
 144                 }
 145                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = *s;
 146                 if (*s)
 147                         wsi->u.hdr.ah->frags[
 148                                         wsi->u.hdr.ah->next_frag_index].len++;
 149         } while (*s++);
 150
 151         return 0;
 152 }
 153
 154 static char char_to_hex(const char c)
 155 {
 156         if (c >= '0' && c <= '9')
 157                 return c - '0';
 158
 159         if (c >= 'a' && c <= 'f')
 160                 return c - 'a' + 10;
 161
 162         if (c >= 'A' && c <= 'F')
 163                 return c - 'A' + 10;
 164
 165         return -1;
 166 }
 167
 168 static int issue_char(struct libwebsocket *wsi, unsigned char c)
 169 {
 170         if (wsi->u.hdr.ah->pos == sizeof(wsi->u.hdr.ah->data)) {
 171                 lwsl_warn("excessive header content\n");
 172                 return -1;
 173         }
 174
 175         if( wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len >=
 176                 wsi->u.hdr.current_token_limit) {
 177                 lwsl_warn("header %i exceeds limit\n", wsi->u.hdr.parser_state);
 178                 return 1;
 179         };
 180
 181         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = c;
 182         if (c)
 183                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len++;
 184
 185         return 0;
 186 }
 187
 188 int libwebsocket_parse(
 189                 struct libwebsocket_context *context,
 190                 struct libwebsocket *wsi, unsigned char c)
 191 {
 192         int n;
 193
 194         switch (wsi->u.hdr.parser_state) {
 195         case WSI_TOKEN_GET_URI:
 196         case WSI_TOKEN_POST_URI:
 197         case WSI_TOKEN_OPTIONS_URI:
 198         case WSI_TOKEN_HOST:
 199         case WSI_TOKEN_CONNECTION:
 200         case WSI_TOKEN_KEY1:
 201         case WSI_TOKEN_KEY2:
 202         case WSI_TOKEN_PROTOCOL:
 203         case WSI_TOKEN_UPGRADE:
 204         case WSI_TOKEN_ORIGIN:
 205         case WSI_TOKEN_SWORIGIN:
 206         case WSI_TOKEN_DRAFT:
 207         case WSI_TOKEN_CHALLENGE:
 208         case WSI_TOKEN_KEY:
 209         case WSI_TOKEN_VERSION:
 210         case WSI_TOKEN_ACCEPT:
 211         case WSI_TOKEN_NONCE:
 212         case WSI_TOKEN_EXTENSIONS:
 213         case WSI_TOKEN_HTTP:
 214         case WSI_TOKEN_HTTP_ACCEPT:
 215         case WSI_TOKEN_HTTP_AC_REQUEST_HEADERS:
 216         case WSI_TOKEN_HTTP_IF_MODIFIED_SINCE:
 217         case WSI_TOKEN_HTTP_IF_NONE_MATCH:
 218         case WSI_TOKEN_HTTP_ACCEPT_ENCODING:
 219         case WSI_TOKEN_HTTP_ACCEPT_LANGUAGE:
 220         case WSI_TOKEN_HTTP_PRAGMA:
 221         case WSI_TOKEN_HTTP_CACHE_CONTROL:
 222         case WSI_TOKEN_HTTP_AUTHORIZATION:
 223         case WSI_TOKEN_HTTP_COOKIE:
 224         case WSI_TOKEN_HTTP_CONTENT_LENGTH:
 225         case WSI_TOKEN_HTTP_CONTENT_TYPE:
 226         case WSI_TOKEN_HTTP_DATE:
 227         case WSI_TOKEN_HTTP_RANGE:
 228         case WSI_TOKEN_HTTP_REFERER:
 229
 230
 231                 lwsl_parser("WSI_TOK_(%d) '%c'\n", wsi->u.hdr.parser_state, c);
 232
 233                 /* collect into malloc'd buffers */
 234                 /* optional initial space swallow */
 235                 if (!wsi->u.hdr.ah->frags[wsi->u.hdr.ah->frag_index[
 236                                       wsi->u.hdr.parser_state]].len && c == ' ')
 237                         break;
 238
 239                 if ((wsi->u.hdr.parser_state != WSI_TOKEN_GET_URI) &&
 240                         (wsi->u.hdr.parser_state != WSI_TOKEN_POST_URI) &&
 241                         (wsi->u.hdr.parser_state != WSI_TOKEN_OPTIONS_URI))
 242                         goto check_eol;
 243
 244                 /* special URI processing... end at space */
 245
 246                 if (c == ' ') {
 247                         /* enforce starting with / */
 248                         if (!wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len)
 249                                 if (issue_char(wsi, '/') < 0)
 250                                         return -1;
 251                         c = '\0';
 252                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 253                         goto spill;
 254                 }
 255
 256                 /* special URI processing... convert %xx */
 257
 258                 switch (wsi->u.hdr.ues) {
 259                 case URIES_IDLE:
 260                         if (c == '%') {
 261                                 wsi->u.hdr.ues = URIES_SEEN_PERCENT;
 262                                 goto swallow;
 263                         }
 264                         break;
 265                 case URIES_SEEN_PERCENT:
 266                         if (char_to_hex(c) < 0) {
 267                                 /* regurgitate */
 268                                 if (issue_char(wsi, '%') < 0)
 269                                         return -1;
 270                                 wsi->u.hdr.ues = URIES_IDLE;
 271                                 /* continue on to assess c */
 272                                 break;
 273                         }
 274                         wsi->u.hdr.esc_stash = c;
 275                         wsi->u.hdr.ues = URIES_SEEN_PERCENT_H1;
 276                         goto swallow;
 277
 278                 case URIES_SEEN_PERCENT_H1:
 279                         if (char_to_hex(c) < 0) {
 280                                 /* regurgitate */
 281                                 issue_char(wsi, '%');
 282                                 wsi->u.hdr.ues = URIES_IDLE;
 283                                 /* regurgitate + assess */
 284                                 if (libwebsocket_parse(context, wsi, wsi->u.hdr.esc_stash) < 0)
 285                                         return -1;
 286                                 /* continue on to assess c */
 287                                 break;
 288                         }
 289                         c = (char_to_hex(wsi->u.hdr.esc_stash) << 4) |
 290                                         char_to_hex(c);
 291                         wsi->u.hdr.ues = URIES_IDLE;
 292                         break;
 293                 }
 294
 295                 /*
 296                  * special URI processing...
 297                  *  convert /.. or /... or /../ etc to /
 298                  *  convert /./ to /
 299                  *  convert // or /// etc to /
 300                  *  leave /.dir or whatever alone
 301                  */
 302
 303                 switch (wsi->u.hdr.ups) {
 304                 case URIPS_IDLE:
 305                         /* issue the first / always */
 306                         if (c == '/')
 307                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 308                         break;
 309                 case URIPS_SEEN_SLASH:
 310                         /* swallow subsequent slashes */
 311                         if (c == '/')
 312                                 goto swallow;
 313                         /* track and swallow the first . after / */
 314                         if (c == '.') {
 315                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT;
 316                                 goto swallow;
 317                         } else
 318                                 wsi->u.hdr.ups = URIPS_IDLE;
 319                         break;
 320                 case URIPS_SEEN_SLASH_DOT:
 321                         /* swallow second . */
 322                         if (c == '.') {
 323                                 /*
 324                                  * back up one dir level if possible
 325                                  * safe against header fragmentation because
 326                                  * the method URI can only be in 1 fragment
 327                                  */
 328                                 if (wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len > 2) {
 329                                         wsi->u.hdr.ah->pos--;
 330                                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len--;
 331                                         do {
 332                                                 wsi->u.hdr.ah->pos--;
 333                                                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len--;
 334                                         } while (wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len > 1 &&
 335                                                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos] != '/');
 336                                 }
 337                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT_DOT;
 338                                 goto swallow;
 339                         }
 340                         /* change /./ to / */
 341                         if (c == '/') {
 342                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 343                                 goto swallow;
 344                         }
 345                         /* it was like /.dir ... regurgitate the . */
 346                         wsi->u.hdr.ups = URIPS_IDLE;
 347                         issue_char(wsi, '.');
 348                         break;
 349
 350                 case URIPS_SEEN_SLASH_DOT_DOT:
 351                         /* swallow prior .. chars and any subsequent . */
 352                         if (c == '.')
 353                                 goto swallow;
 354                         /* last issued was /, so another / == // */
 355                         if (c == '/')
 356                                 goto swallow;
 357                         else /* last we issued was / so SEEN_SLASH */
 358                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 359                         break;
 360                 case URIPS_ARGUMENTS:
 361                         /* leave them alone */
 362                         break;
 363                 }
 364
 365 check_eol:
 366
 367                 /* bail at EOL */
 368                 if (wsi->u.hdr.parser_state != WSI_TOKEN_CHALLENGE &&
 369                                                                   c == '\x0d') {
 370                         c = '\0';
 371                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 372                         lwsl_parser("*\n");
 373                 }
 374
 375                 if (c == '?') { /* start of URI arguments */
 376                         /* seal off uri header */
 377                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 378
 379                         /* move to using WSI_TOKEN_HTTP_URI_ARGS */
 380                         wsi->u.hdr.ah->next_frag_index++;
 381                         wsi->u.hdr.ah->frags[
 382                                 wsi->u.hdr.ah->next_frag_index].offset =
 383                                                              wsi->u.hdr.ah->pos;
 384                         wsi->u.hdr.ah->frags[
 385                                         wsi->u.hdr.ah->next_frag_index].len = 0;
 386                         wsi->u.hdr.ah->frags[
 387                             wsi->u.hdr.ah->next_frag_index].next_frag_index = 0;
 388
 389                         wsi->u.hdr.ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS] =
 390                                                  wsi->u.hdr.ah->next_frag_index;
 391
 392                         /* defeat normal uri path processing */
 393                         wsi->u.hdr.ups = URIPS_ARGUMENTS;
 394                         goto swallow;
 395                 }
 396
 397 spill:
 398                 {
 399                         int issue_result = issue_char(wsi, c);
 400                         if (issue_result < 0) {
 401                                 return -1;
 402                         }
 403                         else if(issue_result > 0) {
 404                                 wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 405                         };
 406                 };
 407 swallow:
 408                 /* per-protocol end of headers management */
 409
 410                 if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 411                         goto set_parsing_complete;
 412                 break;
 413
 414                 /* collecting and checking a name part */
 415         case WSI_TOKEN_NAME_PART:
 416                 lwsl_parser("WSI_TOKEN_NAME_PART '%c'\n", c);
 417
 418                 wsi->u.hdr.lextable_pos =
 419                                 lextable_decode(wsi->u.hdr.lextable_pos, c);
 420
 421                 if (wsi->u.hdr.lextable_pos < 0) {
 422                         /* this is not a header we know about */
 423                         if (wsi->u.hdr.ah->frag_index[WSI_TOKEN_GET_URI] ||
 424                                 wsi->u.hdr.ah->frag_index[WSI_TOKEN_POST_URI] ||
 425                                 wsi->u.hdr.ah->frag_index[WSI_TOKEN_OPTIONS_URI] ||
 426                                 wsi->u.hdr.ah->frag_index[WSI_TOKEN_HTTP]) {
 427                                 /*
 428                                  * altready had the method, no idea what
 429                                  * this crap is, ignore
 430                                  */
 431                                 wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 432                                 break;
 433                         }
 434                         /*
 435                          * hm it's an unknown http method in fact,
 436                          * treat as dangerous
 437                          */
 438
 439                         lwsl_info("Unknown method - dropping\n");
 440                         return -1;
 441                 }
 442                 if (lextable[wsi->u.hdr.lextable_pos] < FAIL_CHAR) {
 443
 444                         /* terminal state */
 445
 446                         n = (lextable[wsi->u.hdr.lextable_pos] << 8) | lextable[wsi->u.hdr.lextable_pos + 1];
 447
 448                         lwsl_parser("known hdr %d\n", n);
 449                         if (n == WSI_TOKEN_GET_URI &&
 450                                 wsi->u.hdr.ah->frag_index[WSI_TOKEN_GET_URI]) {
 451                                 lwsl_warn("Duplicated GET\n");
 452                                 return -1;
 453                         } else if (n == WSI_TOKEN_POST_URI &&
 454                                 wsi->u.hdr.ah->frag_index[WSI_TOKEN_POST_URI]) {
 455                                 lwsl_warn("Duplicated POST\n");
 456                                 return -1;
 457                         } else if (n == WSI_TOKEN_OPTIONS_URI &&
 458                                 wsi->u.hdr.ah->frag_index[WSI_TOKEN_OPTIONS_URI]) {
 459                                 lwsl_warn("Duplicated OPTIONS\n");
 460                                 return -1;
 461                         }
 462
 463                         /*
 464                          * WSORIGIN is protocol equiv to ORIGIN,
 465                          * JWebSocket likes to send it, map to ORIGIN
 466                          */
 467                         if (n == WSI_TOKEN_SWORIGIN)
 468                                 n = WSI_TOKEN_ORIGIN;
 469
 470                         wsi->u.hdr.parser_state = (enum lws_token_indexes)
 471                                                         (WSI_TOKEN_GET_URI + n);
 472
 473                         if( context->token_limits ) {
 474                                 wsi->u.hdr.current_token_limit = \
 475                                         context->token_limits->token_limit[wsi->u.hdr.parser_state];
 476                         }
 477                         else {
 478                                 wsi->u.hdr.current_token_limit = sizeof(wsi->u.hdr.ah->data);
 479                         };
 480
 481                         if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 482                                 goto set_parsing_complete;
 483
 484                         goto start_fragment;
 485                 }
 486                 break;
 487
 488 start_fragment:
 489                 wsi->u.hdr.ah->next_frag_index++;
 490                 if (wsi->u.hdr.ah->next_frag_index ==
 491                                 sizeof(wsi->u.hdr.ah->frags) /
 492                                               sizeof(wsi->u.hdr.ah->frags[0])) {
 493                         lwsl_warn("More hdr frags than we can deal with\n");
 494                         return -1;
 495                 }
 496
 497                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].offset =
 498                                                              wsi->u.hdr.ah->pos;
 499                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len = 0;
 500                 wsi->u.hdr.ah->frags[
 501                             wsi->u.hdr.ah->next_frag_index].next_frag_index = 0;
 502
 503                 n = wsi->u.hdr.ah->frag_index[wsi->u.hdr.parser_state];
 504                 if (!n) { /* first fragment */
 505                         wsi->u.hdr.ah->frag_index[wsi->u.hdr.parser_state] =
 506                                                  wsi->u.hdr.ah->next_frag_index;
 507                         break;
 508                 }
 509                 /* continuation */
 510                 while (wsi->u.hdr.ah->frags[n].next_frag_index)
 511                                 n = wsi->u.hdr.ah->frags[n].next_frag_index;
 512                 wsi->u.hdr.ah->frags[n].next_frag_index =
 513                                                  wsi->u.hdr.ah->next_frag_index;
 514
 515                 if (wsi->u.hdr.ah->pos == sizeof(wsi->u.hdr.ah->data)) {
 516                         lwsl_warn("excessive header content\n");
 517                         return -1;
 518                 }
 519
 520                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = ' ';
 521                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len++;
 522                 break;
 523
 524                 /* skipping arg part of a name we didn't recognize */
 525         case WSI_TOKEN_SKIPPING:
 526                 lwsl_parser("WSI_TOKEN_SKIPPING '%c'\n", c);
 527
 528                 if (c == '\x0d')
 529                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 530                 break;
 531
 532         case WSI_TOKEN_SKIPPING_SAW_CR:
 533                 lwsl_parser("WSI_TOKEN_SKIPPING_SAW_CR '%c'\n", c);
 534                 if (c == '\x0a') {
 535                         wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 536                         wsi->u.hdr.lextable_pos = 0;
 537                 } else
 538                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 539                 break;
 540                 /* we're done, ignore anything else */
 541
 542         case WSI_PARSING_COMPLETE:
 543                 lwsl_parser("WSI_PARSING_COMPLETE '%c'\n", c);
 544                 break;
 545
 546         default:        /* keep gcc happy */
 547                 break;
 548         }
 549
 550         return 0;
 551
 552 set_parsing_complete:
 553
 554         if (lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE)) {
 555                 if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION))
 556                         wsi->ietf_spec_revision =
 557                                atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION));
 558
 559                 lwsl_parser("v%02d hdrs completed\n", wsi->ietf_spec_revision);
 560         }
 561         wsi->u.hdr.parser_state = WSI_PARSING_COMPLETE;
 562         wsi->hdr_parsing_completed = 1;
 563
 564         return 0;
 565 }
 566
 567
 568 /**
 569  * lws_frame_is_binary: true if the current frame was sent in binary mode
 570  *
 571  * @wsi: the connection we are inquiring about
 572  *
 573  * This is intended to be called from the LWS_CALLBACK_RECEIVE callback if
 574  * it's interested to see if the frame it's dealing with was sent in binary
 575  * mode.
 576  */
 577
 578 LWS_VISIBLE int lws_frame_is_binary(struct libwebsocket *wsi)
 579 {
 580         return wsi->u.ws.frame_is_binary;
 581 }
 582
 583 int
 584 libwebsocket_rx_sm(struct libwebsocket *wsi, unsigned char c)
 585 {
 586         int n;
 587         struct lws_tokens eff_buf;
 588         int ret = 0;
 589
 590         switch (wsi->lws_rx_parse_state) {
 591         case LWS_RXPS_NEW:
 592
 593                 switch (wsi->ietf_spec_revision) {
 594                 case 13:
 595                         /*
 596                          * no prepended frame key any more
 597                          */
 598                         wsi->u.ws.all_zero_nonce = 1;
 599                         goto handle_first;
 600
 601                 default:
 602                         lwsl_warn("lws_rx_sm: unknown spec version %d\n",
 603                                                        wsi->ietf_spec_revision);
 604                         break;
 605                 }
 606                 break;
 607         case LWS_RXPS_04_MASK_NONCE_1:
 608                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 609                 if (c)
 610                         wsi->u.ws.all_zero_nonce = 0;
 611                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_2;
 612                 break;
 613         case LWS_RXPS_04_MASK_NONCE_2:
 614                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 615                 if (c)
 616                         wsi->u.ws.all_zero_nonce = 0;
 617                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_3;
 618                 break;
 619         case LWS_RXPS_04_MASK_NONCE_3:
 620                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 621                 if (c)
 622                         wsi->u.ws.all_zero_nonce = 0;
 623
 624                 /*
 625                  * start from the zero'th byte in the XOR key buffer since
 626                  * this is the start of a frame with a new key
 627                  */
 628
 629                 wsi->u.ws.frame_mask_index = 0;
 630
 631                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
 632                 break;
 633
 634         /*
 635          *  04 logical framing from the spec (all this is masked when incoming
 636          *  and has to be unmasked)
 637          *
 638          * We ignore the possibility of extension data because we don't
 639          * negotiate any extensions at the moment.
 640          *
 641          *    0                   1                   2                   3
 642          *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 643          *   +-+-+-+-+-------+-+-------------+-------------------------------+
 644          *   |F|R|R|R| opcode|R| Payload len |    Extended payload length    |
 645          *   |I|S|S|S|  (4)  |S|     (7)     |             (16/63)           |
 646          *   |N|V|V|V|       |V|             |   (if payload len==126/127)   |
 647          *   | |1|2|3|       |4|             |                               |
 648          *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 649          *   |     Extended payload length continued, if payload len == 127  |
 650          *   + - - - - - - - - - - - - - - - +-------------------------------+
 651          *   |                               |         Extension data        |
 652          *   +-------------------------------+ - - - - - - - - - - - - - - - +
 653          *   :                                                               :
 654          *   +---------------------------------------------------------------+
 655          *   :                       Application data                        :
 656          *   +---------------------------------------------------------------+
 657          *
 658          *  We pass payload through to userland as soon as we get it, ignoring
 659          *  FIN.  It's up to userland to buffer it up if it wants to see a
 660          *  whole unfragmented block of the original size (which may be up to
 661          *  2^63 long!)
 662          */
 663
 664         case LWS_RXPS_04_FRAME_HDR_1:
 665 handle_first:
 666
 667                 wsi->u.ws.opcode = c & 0xf;
 668                 wsi->u.ws.rsv = c & 0x70;
 669                 wsi->u.ws.final = !!((c >> 7) & 1);
 670
 671                 switch (wsi->u.ws.opcode) {
 672                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 673                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 674                         wsi->u.ws.frame_is_binary =
 675                              wsi->u.ws.opcode == LWS_WS_OPCODE_07__BINARY_FRAME;
 676                         break;
 677                 }
 678                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN;
 679                 break;
 680
 681         case LWS_RXPS_04_FRAME_HDR_LEN:
 682
 683                 wsi->u.ws.this_frame_masked = !!(c & 0x80);
 684
 685                 switch (c & 0x7f) {
 686                 case 126:
 687                         /* control frames are not allowed to have big lengths */
 688                         if (wsi->u.ws.opcode & 8)
 689                                 goto illegal_ctl_length;
 690
 691                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2;
 692                         break;
 693                 case 127:
 694                         /* control frames are not allowed to have big lengths */
 695                         if (wsi->u.ws.opcode & 8)
 696                                 goto illegal_ctl_length;
 697
 698                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8;
 699                         break;
 700                 default:
 701                         wsi->u.ws.rx_packet_length = c & 0x7f;
 702                         if (wsi->u.ws.this_frame_masked)
 703                                 wsi->lws_rx_parse_state =
 704                                                 LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 705                         else
 706                                 if (wsi->u.ws.rx_packet_length)
 707                                         wsi->lws_rx_parse_state =
 708                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 709                                 else {
 710                                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 711                                         goto spill;
 712                                 }
 713                         break;
 714                 }
 715                 break;
 716
 717         case LWS_RXPS_04_FRAME_HDR_LEN16_2:
 718                 wsi->u.ws.rx_packet_length = c << 8;
 719                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1;
 720                 break;
 721
 722         case LWS_RXPS_04_FRAME_HDR_LEN16_1:
 723                 wsi->u.ws.rx_packet_length |= c;
 724                 if (wsi->u.ws.this_frame_masked)
 725                         wsi->lws_rx_parse_state =
 726                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 727                 else
 728                         wsi->lws_rx_parse_state =
 729                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 730                 break;
 731
 732         case LWS_RXPS_04_FRAME_HDR_LEN64_8:
 733                 if (c & 0x80) {
 734                         lwsl_warn("b63 of length must be zero\n");
 735                         /* kill the connection */
 736                         return -1;
 737                 }
 738 #if defined __LP64__
 739                 wsi->u.ws.rx_packet_length = ((size_t)c) << 56;
 740 #else
 741                 wsi->u.ws.rx_packet_length = 0;
 742 #endif
 743                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7;
 744                 break;
 745
 746         case LWS_RXPS_04_FRAME_HDR_LEN64_7:
 747 #if defined __LP64__
 748                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 48;
 749 #endif
 750                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6;
 751                 break;
 752
 753         case LWS_RXPS_04_FRAME_HDR_LEN64_6:
 754 #if defined __LP64__
 755                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 40;
 756 #endif
 757                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5;
 758                 break;
 759
 760         case LWS_RXPS_04_FRAME_HDR_LEN64_5:
 761 #if defined __LP64__
 762                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 32;
 763 #endif
 764                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4;
 765                 break;
 766
 767         case LWS_RXPS_04_FRAME_HDR_LEN64_4:
 768                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 24;
 769                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3;
 770                 break;
 771
 772         case LWS_RXPS_04_FRAME_HDR_LEN64_3:
 773                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 16;
 774                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2;
 775                 break;
 776
 777         case LWS_RXPS_04_FRAME_HDR_LEN64_2:
 778                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 8;
 779                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1;
 780                 break;
 781
 782         case LWS_RXPS_04_FRAME_HDR_LEN64_1:
 783                 wsi->u.ws.rx_packet_length |= ((size_t)c);
 784                 if (wsi->u.ws.this_frame_masked)
 785                         wsi->lws_rx_parse_state =
 786                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 787                 else
 788                         wsi->lws_rx_parse_state =
 789                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 790                 break;
 791
 792         case LWS_RXPS_07_COLLECT_FRAME_KEY_1:
 793                 wsi->u.ws.frame_masking_nonce_04[0] = c;
 794                 if (c)
 795                         wsi->u.ws.all_zero_nonce = 0;
 796                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2;
 797                 break;
 798
 799         case LWS_RXPS_07_COLLECT_FRAME_KEY_2:
 800                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 801                 if (c)
 802                         wsi->u.ws.all_zero_nonce = 0;
 803                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3;
 804                 break;
 805
 806         case LWS_RXPS_07_COLLECT_FRAME_KEY_3:
 807                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 808                 if (c)
 809                         wsi->u.ws.all_zero_nonce = 0;
 810                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4;
 811                 break;
 812
 813         case LWS_RXPS_07_COLLECT_FRAME_KEY_4:
 814                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 815                 if (c)
 816                         wsi->u.ws.all_zero_nonce = 0;
 817                 wsi->lws_rx_parse_state =
 818                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 819                 wsi->u.ws.frame_mask_index = 0;
 820                 if (wsi->u.ws.rx_packet_length == 0) {
 821                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 822                         goto spill;
 823                 }
 824                 break;
 825
 826
 827         case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
 828
 829                 if (!wsi->u.ws.rx_user_buffer)
 830                         lwsl_err("NULL user buffer...\n");
 831
 832                 if (wsi->u.ws.all_zero_nonce)
 833                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 834                                (wsi->u.ws.rx_user_buffer_head++)] = c;
 835                 else
 836                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 837                                (wsi->u.ws.rx_user_buffer_head++)] =
 838                                    c ^ wsi->u.ws.frame_masking_nonce_04[
 839                                             (wsi->u.ws.frame_mask_index++) & 3];
 840
 841                 if (--wsi->u.ws.rx_packet_length == 0) {
 842                         /* spill because we have the whole frame */
 843                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 844                         goto spill;
 845                 }
 846
 847                 /*
 848                  * if there's no protocol max frame size given, we are
 849                  * supposed to default to LWS_MAX_SOCKET_IO_BUF
 850                  */
 851
 852                 if (!wsi->protocol->rx_buffer_size &&
 853                                         wsi->u.ws.rx_user_buffer_head !=
 854                                                           LWS_MAX_SOCKET_IO_BUF)
 855                         break;
 856                 else
 857                         if (wsi->protocol->rx_buffer_size &&
 858                                         wsi->u.ws.rx_user_buffer_head !=
 859                                                   wsi->protocol->rx_buffer_size)
 860                         break;
 861
 862                 /* spill because we filled our rx buffer */
 863 spill:
 864                 /*
 865                  * is this frame a control packet we should take care of at this
 866                  * layer?  If so service it and hide it from the user callback
 867                  */
 868
 869                 lwsl_parser("spill on %s\n", wsi->protocol->name);
 870
 871                 switch (wsi->u.ws.opcode) {
 872                 case LWS_WS_OPCODE_07__CLOSE:
 873                         /* is this an acknowledgement of our close? */
 874                         if (wsi->state == WSI_STATE_AWAITING_CLOSE_ACK) {
 875                                 /*
 876                                  * fine he has told us he is closing too, let's
 877                                  * finish our close
 878                                  */
 879                                 lwsl_parser("seen client close ack\n");
 880                                 return -1;
 881                         }
 882                         lwsl_parser("server sees client close packet\n");
 883                         /* parrot the close packet payload back */
 884                         n = libwebsocket_write(wsi, (unsigned char *)
 885                                 &wsi->u.ws.rx_user_buffer[
 886                                         LWS_SEND_BUFFER_PRE_PADDING],
 887                                         wsi->u.ws.rx_user_buffer_head,
 888                                                                LWS_WRITE_CLOSE);
 889                         if (n < 0)
 890                                 lwsl_info("write of close ack failed %d\n", n);
 891                         wsi->state = WSI_STATE_RETURNED_CLOSE_ALREADY;
 892                         /* close the connection */
 893                         return -1;
 894
 895                 case LWS_WS_OPCODE_07__PING:
 896                         lwsl_info("received %d byte ping, sending pong\n",
 897                                                  wsi->u.ws.rx_user_buffer_head);
 898                         lwsl_hexdump(&wsi->u.ws.rx_user_buffer[
 899                                         LWS_SEND_BUFFER_PRE_PADDING],
 900                                                  wsi->u.ws.rx_user_buffer_head);
 901                         /* parrot the ping packet payload back as a pong */
 902                         n = libwebsocket_write(wsi, (unsigned char *)
 903                         &wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
 904                                  wsi->u.ws.rx_user_buffer_head, LWS_WRITE_PONG);
 905                         if (n < 0)
 906                                 return -1;
 907                         /* ... then just drop it */
 908                         wsi->u.ws.rx_user_buffer_head = 0;
 909                         return 0;
 910
 911                 case LWS_WS_OPCODE_07__PONG:
 912                         /* ... then just drop it */
 913                         wsi->u.ws.rx_user_buffer_head = 0;
 914                         return 0;
 915
 916                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 917                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 918                 case LWS_WS_OPCODE_07__CONTINUATION:
 919                         break;
 920
 921                 default:
 922                         lwsl_parser("passing opc %x up to exts\n",
 923                                                         wsi->u.ws.opcode);
 924                         /*
 925                          * It's something special we can't understand here.
 926                          * Pass the payload up to the extension's parsing
 927                          * state machine.
 928                          */
 929
 930                         eff_buf.token = &wsi->u.ws.rx_user_buffer[
 931                                                    LWS_SEND_BUFFER_PRE_PADDING];
 932                         eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 933
 934                         if (lws_ext_callback_for_each_active(wsi,
 935                                 LWS_EXT_CALLBACK_EXTENDED_PAYLOAD_RX,
 936                                         &eff_buf, 0) <= 0) /* not handle or fail */
 937                                 lwsl_ext("ext opc opcode 0x%x unknown\n",
 938                                                               wsi->u.ws.opcode);
 939
 940                         wsi->u.ws.rx_user_buffer_head = 0;
 941                         return 0;
 942                 }
 943
 944                 /*
 945                  * No it's real payload, pass it up to the user callback.
 946                  * It's nicely buffered with the pre-padding taken care of
 947                  * so it can be sent straight out again using libwebsocket_write
 948                  */
 949
 950                 eff_buf.token = &wsi->u.ws.rx_user_buffer[
 951                                                 LWS_SEND_BUFFER_PRE_PADDING];
 952                 eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 953
 954                 if (lws_ext_callback_for_each_active(wsi,
 955                                 LWS_EXT_CALLBACK_PAYLOAD_RX, &eff_buf, 0) < 0)
 956                         return -1;
 957
 958                 if (eff_buf.token_len > 0) {
 959                         eff_buf.token[eff_buf.token_len] = '\0';
 960
 961                         if (wsi->protocol->callback)
 962                                 ret = user_callback_handle_rxflow(
 963                                                 wsi->protocol->callback,
 964                                                 wsi->protocol->owning_server,
 965                                                 wsi, LWS_CALLBACK_RECEIVE,
 966                                                 wsi->user_space,
 967                                                 eff_buf.token,
 968                                                 eff_buf.token_len);
 969                     else
 970                             lwsl_err("No callback on payload spill!\n");
 971                 }
 972
 973                 wsi->u.ws.rx_user_buffer_head = 0;
 974                 break;
 975         }
 976
 977         return ret;
 978
 979 illegal_ctl_length:
 980
 981         lwsl_warn("Control frame with xtended length is illegal\n");
 982         /* kill the connection */
 983         return -1;
 984 }
 985
 986
 987 /**
 988  * libwebsockets_remaining_packet_payload() - Bytes to come before "overall"
 989  *                                            rx packet is complete
 990  * @wsi:                Websocket instance (available from user callback)
 991  *
 992  *      This function is intended to be called from the callback if the
 993  *  user code is interested in "complete packets" from the client.
 994  *  libwebsockets just passes through payload as it comes and issues a buffer
 995  *  additionally when it hits a built-in limit.  The LWS_CALLBACK_RECEIVE
 996  *  callback handler can use this API to find out if the buffer it has just
 997  *  been given is the last piece of a "complete packet" from the client --
 998  *  when that is the case libwebsockets_remaining_packet_payload() will return
 999  *  0.
1000  *
1001  *  Many protocols won't care becuse their packets are always small.
1002  */
1003
1004 LWS_VISIBLE size_t
1005 libwebsockets_remaining_packet_payload(struct libwebsocket *wsi)
1006 {
1007         return wsi->u.ws.rx_packet_length;
1008 }