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
  46                 if (lextable[pos] == FAIL_CHAR)
  47                         return -1;
  48
  49                 /* b7 = 0, end or 3-byte */
  50                 if (lextable[pos] < FAIL_CHAR) /* terminal marker */
  51                         return pos;
  52
  53                 if (lextable[pos] == c) /* goto */
  54                         return pos + (lextable[pos + 1]) +
  55                                                 (lextable[pos + 2] << 8);
  56                 /* fall thru goto */
  57                 pos += 3;
  58                 /* continue */
  59         }
  60 }
  61
  62 int lws_allocate_header_table(struct libwebsocket *wsi)
  63 {
  64         /* Be sure to free any existing header data to avoid mem leak: */
  65         lws_free_header_table(wsi);
  66         wsi->u.hdr.ah = lws_malloc(sizeof(*wsi->u.hdr.ah));
  67         if (wsi->u.hdr.ah == NULL) {
  68                 lwsl_err("Out of memory\n");
  69                 return -1;
  70         }
  71         memset(wsi->u.hdr.ah->frag_index, 0, sizeof(wsi->u.hdr.ah->frag_index));
  72         wsi->u.hdr.ah->next_frag_index = 0;
  73         wsi->u.hdr.ah->pos = 0;
  74
  75         return 0;
  76 }
  77
  78 int lws_free_header_table(struct libwebsocket *wsi)
  79 {
  80         lws_free2(wsi->u.hdr.ah);
  81         wsi->u.hdr.ah = NULL;
  82         return 0;
  83 };
  84
  85 LWS_VISIBLE int lws_hdr_total_length(struct libwebsocket *wsi, enum lws_token_indexes h)
  86 {
  87         int n;
  88         int len = 0;
  89
  90         n = wsi->u.hdr.ah->frag_index[h];
  91         if (!n)
  92                 return 0;
  93         do {
  94                 len += wsi->u.hdr.ah->frags[n].len;
  95                 n = wsi->u.hdr.ah->frags[n].next_frag_index;
  96         } while (n);
  97
  98         return len;
  99 }
 100
 101 LWS_VISIBLE int lws_hdr_copy(struct libwebsocket *wsi, char *dest, int len,
 102                                                 enum lws_token_indexes h)
 103 {
 104         int toklen = lws_hdr_total_length(wsi, h);
 105         int n;
 106
 107         if (toklen >= len)
 108                 return -1;
 109
 110         n = wsi->u.hdr.ah->frag_index[h];
 111         if (!n)
 112                 return 0;
 113
 114         do {
 115                 strcpy(dest,
 116                         &wsi->u.hdr.ah->data[wsi->u.hdr.ah->frags[n].offset]);
 117                 dest += wsi->u.hdr.ah->frags[n].len;
 118                 n = wsi->u.hdr.ah->frags[n].next_frag_index;
 119         } while (n);
 120
 121         return toklen;
 122 }
 123
 124 char *lws_hdr_simple_ptr(struct libwebsocket *wsi, enum lws_token_indexes h)
 125 {
 126         int n;
 127
 128         n = wsi->u.hdr.ah->frag_index[h];
 129         if (!n)
 130                 return NULL;
 131
 132         return &wsi->u.hdr.ah->data[wsi->u.hdr.ah->frags[n].offset];
 133 }
 134
 135 int lws_hdr_simple_create(struct libwebsocket *wsi,
 136                                 enum lws_token_indexes h, const char *s)
 137 {
 138         wsi->u.hdr.ah->next_frag_index++;
 139         if (wsi->u.hdr.ah->next_frag_index ==
 140                sizeof(wsi->u.hdr.ah->frags) / sizeof(wsi->u.hdr.ah->frags[0])) {
 141                 lwsl_warn("More hdr frags than we can deal with, dropping\n");
 142                 return -1;
 143         }
 144
 145         wsi->u.hdr.ah->frag_index[h] = wsi->u.hdr.ah->next_frag_index;
 146
 147         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].offset =
 148                                                              wsi->u.hdr.ah->pos;
 149         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len = 0;
 150         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].next_frag_index =
 151                                                                               0;
 152
 153         do {
 154                 if (wsi->u.hdr.ah->pos == sizeof(wsi->u.hdr.ah->data)) {
 155                         lwsl_err("Ran out of header data space\n");
 156                         return -1;
 157                 }
 158                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = *s;
 159                 if (*s)
 160                         wsi->u.hdr.ah->frags[
 161                                         wsi->u.hdr.ah->next_frag_index].len++;
 162         } while (*s++);
 163
 164         return 0;
 165 }
 166
 167 static signed char char_to_hex(const char c)
 168 {
 169         if (c >= '0' && c <= '9')
 170                 return c - '0';
 171
 172         if (c >= 'a' && c <= 'f')
 173                 return c - 'a' + 10;
 174
 175         if (c >= 'A' && c <= 'F')
 176                 return c - 'A' + 10;
 177
 178         return -1;
 179 }
 180
 181 static int issue_char(struct libwebsocket *wsi, unsigned char c)
 182 {
 183         unsigned short frag_len;
 184         if (wsi->u.hdr.ah->pos == sizeof(wsi->u.hdr.ah->data)) {
 185                 lwsl_warn("excessive header content\n");
 186                 return -1;
 187         }
 188
 189         frag_len = \
 190                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len;
 191         /* If we haven't hit the token limit, just copy the character into
 192          * the header: */
 193         if( frag_len < wsi->u.hdr.current_token_limit ) {
 194                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = c;
 195                 if (c)
 196                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len++;
 197                 return 0;
 198         }
 199         else {
 200                 /* Insert a null character when we *hit* the limit: */
 201                 if( frag_len == wsi->u.hdr.current_token_limit ) {
 202                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 203                         lwsl_warn("header %i exceeds limit\n", wsi->u.hdr.parser_state);
 204                 };
 205         };
 206         return 1;
 207 }
 208
 209 int libwebsocket_parse(
 210                 struct libwebsocket_context *context,
 211                 struct libwebsocket *wsi, unsigned char c)
 212 {
 213         static const unsigned char methods[] = {
 214                 WSI_TOKEN_GET_URI,
 215                 WSI_TOKEN_POST_URI,
 216                 WSI_TOKEN_OPTIONS_URI,
 217                 WSI_TOKEN_PUT_URI,
 218                 WSI_TOKEN_PATCH_URI,
 219                 WSI_TOKEN_DELETE_URI,
 220         };
 221         unsigned int n, m;
 222
 223         switch (wsi->u.hdr.parser_state) {
 224         default:
 225
 226                 lwsl_parser("WSI_TOK_(%d) '%c'\n", wsi->u.hdr.parser_state, c);
 227
 228                 /* collect into malloc'd buffers */
 229                 /* optional initial space swallow */
 230                 if (!wsi->u.hdr.ah->frags[wsi->u.hdr.ah->frag_index[
 231                                       wsi->u.hdr.parser_state]].len && c == ' ')
 232                         break;
 233
 234                 for (m = 0; m < ARRAY_SIZE(methods); m++)
 235                         if (wsi->u.hdr.parser_state == methods[m])
 236                                 break;
 237                 if (m == ARRAY_SIZE(methods))
 238                         /* it was not any of the methods */
 239                         goto check_eol;
 240
 241                 /* special URI processing... end at space */
 242
 243                 if (c == ' ') {
 244                         /* enforce starting with / */
 245                         if (!wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len)
 246                                 if (issue_char(wsi, '/') < 0)
 247                                         return -1;
 248
 249                         /* begin parsing HTTP version: */
 250                         if (issue_char(wsi, '\0') < 0)
 251                                 return -1;
 252                         wsi->u.hdr.parser_state = WSI_TOKEN_HTTP;
 253                         goto start_fragment;
 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                         }
 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                         /* 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                 if (c == '?') { /* start of URI arguments */
 366                         /* seal off uri header */
 367                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 368
 369                         /* move to using WSI_TOKEN_HTTP_URI_ARGS */
 370                         wsi->u.hdr.ah->next_frag_index++;
 371                         wsi->u.hdr.ah->frags[
 372                                 wsi->u.hdr.ah->next_frag_index].offset =
 373                                                              wsi->u.hdr.ah->pos;
 374                         wsi->u.hdr.ah->frags[
 375                                         wsi->u.hdr.ah->next_frag_index].len = 0;
 376                         wsi->u.hdr.ah->frags[
 377                             wsi->u.hdr.ah->next_frag_index].next_frag_index = 0;
 378
 379                         wsi->u.hdr.ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS] =
 380                                                  wsi->u.hdr.ah->next_frag_index;
 381
 382                         /* defeat normal uri path processing */
 383                         wsi->u.hdr.ups = URIPS_ARGUMENTS;
 384                         goto swallow;
 385                 }
 386
 387 check_eol:
 388
 389                 /* bail at EOL */
 390                 if (wsi->u.hdr.parser_state != WSI_TOKEN_CHALLENGE &&
 391                                                                   c == '\x0d') {
 392                         c = '\0';
 393                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 394                         lwsl_parser("*\n");
 395                 }
 396
 397                 n = issue_char(wsi, c);
 398                 if ((int)n < 0)
 399                         return -1;
 400                 if (n > 0)
 401                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 402
 403 swallow:
 404                 /* per-protocol end of headers management */
 405
 406                 if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 407                         goto set_parsing_complete;
 408                 break;
 409
 410                 /* collecting and checking a name part */
 411         case WSI_TOKEN_NAME_PART:
 412                 lwsl_parser("WSI_TOKEN_NAME_PART '%c' (mode=%d)\n", c, wsi->mode);
 413
 414                 wsi->u.hdr.lextable_pos =
 415                                 lextable_decode(wsi->u.hdr.lextable_pos, c);
 416                 /*
 417                  * Server needs to look out for unknown methods...
 418                  */
 419                 if (wsi->u.hdr.lextable_pos < 0 &&
 420                     wsi->mode == LWS_CONNMODE_HTTP_SERVING) {
 421                         /* this is not a header we know about */
 422                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 423                                 if (wsi->u.hdr.ah->frag_index[methods[m]]) {
 424                                         /*
 425                                          * already had the method, no idea what
 426                                          * this crap from the client is, ignore
 427                                          */
 428                                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 429                                         break;
 430                                 }
 431                         /*
 432                          * hm it's an unknown http method from a client in fact,
 433                          * treat as dangerous
 434                          */
 435                         if (m == ARRAY_SIZE(methods)) {
 436                                 lwsl_info("Unknown method - dropping\n");
 437                                 return -1;
 438                         }
 439                         break;
 440                 }
 441                 /*
 442                  * ...otherwise for a client, let him ignore unknown headers
 443                  * coming from the server
 444                  */
 445                 if (wsi->u.hdr.lextable_pos < 0) {
 446                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 447                         break;
 448                 }
 449
 450                 if (lextable[wsi->u.hdr.lextable_pos] < FAIL_CHAR) {
 451                         /* terminal state */
 452
 453                         n = ((unsigned int)lextable[wsi->u.hdr.lextable_pos] << 8) |
 454                                         lextable[wsi->u.hdr.lextable_pos + 1];
 455
 456                         lwsl_parser("known hdr %d\n", n);
 457                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 458                                 if (n == methods[m] &&
 459                                                 wsi->u.hdr.ah->frag_index[
 460                                                         methods[m]]) {
 461                                         lwsl_warn("Duplicated method\n");
 462                                         return -1;
 463                                 }
 464
 465                         /*
 466                          * WSORIGIN is protocol equiv to ORIGIN,
 467                          * JWebSocket likes to send it, map to ORIGIN
 468                          */
 469                         if (n == WSI_TOKEN_SWORIGIN)
 470                                 n = WSI_TOKEN_ORIGIN;
 471
 472                         wsi->u.hdr.parser_state = (enum lws_token_indexes)
 473                                                         (WSI_TOKEN_GET_URI + n);
 474
 475                         if (context->token_limits)
 476                                 wsi->u.hdr.current_token_limit =
 477                                         context->token_limits->token_limit[wsi->u.hdr.parser_state];
 478                         else
 479                                 wsi->u.hdr.current_token_limit = sizeof(wsi->u.hdr.ah->data);
 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
 547         return 0;
 548
 549 set_parsing_complete:
 550
 551         if (lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE)) {
 552                 if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION))
 553                         wsi->ietf_spec_revision =
 554                                atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION));
 555
 556                 lwsl_parser("v%02d hdrs completed\n", wsi->ietf_spec_revision);
 557         }
 558         wsi->u.hdr.parser_state = WSI_PARSING_COMPLETE;
 559         wsi->hdr_parsing_completed = 1;
 560
 561         return 0;
 562 }
 563
 564
 565 /**
 566  * lws_frame_is_binary: true if the current frame was sent in binary mode
 567  *
 568  * @wsi: the connection we are inquiring about
 569  *
 570  * This is intended to be called from the LWS_CALLBACK_RECEIVE callback if
 571  * it's interested to see if the frame it's dealing with was sent in binary
 572  * mode.
 573  */
 574
 575 LWS_VISIBLE int lws_frame_is_binary(struct libwebsocket *wsi)
 576 {
 577         return wsi->u.ws.frame_is_binary;
 578 }
 579
 580 int
 581 libwebsocket_rx_sm(struct libwebsocket *wsi, unsigned char c)
 582 {
 583         struct lws_tokens eff_buf;
 584         int ret = 0;
 585         int callback_action = LWS_CALLBACK_RECEIVE;
 586
 587         switch (wsi->lws_rx_parse_state) {
 588         case LWS_RXPS_NEW:
 589
 590                 switch (wsi->ietf_spec_revision) {
 591                 case 13:
 592                         /*
 593                          * no prepended frame key any more
 594                          */
 595                         wsi->u.ws.all_zero_nonce = 1;
 596                         goto handle_first;
 597
 598                 default:
 599                         lwsl_warn("lws_rx_sm: unknown spec version %d\n",
 600                                                        wsi->ietf_spec_revision);
 601                         break;
 602                 }
 603                 break;
 604         case LWS_RXPS_04_MASK_NONCE_1:
 605                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 606                 if (c)
 607                         wsi->u.ws.all_zero_nonce = 0;
 608                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_2;
 609                 break;
 610         case LWS_RXPS_04_MASK_NONCE_2:
 611                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 612                 if (c)
 613                         wsi->u.ws.all_zero_nonce = 0;
 614                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_3;
 615                 break;
 616         case LWS_RXPS_04_MASK_NONCE_3:
 617                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 618                 if (c)
 619                         wsi->u.ws.all_zero_nonce = 0;
 620
 621                 /*
 622                  * start from the zero'th byte in the XOR key buffer since
 623                  * this is the start of a frame with a new key
 624                  */
 625
 626                 wsi->u.ws.frame_mask_index = 0;
 627
 628                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
 629                 break;
 630
 631         /*
 632          *  04 logical framing from the spec (all this is masked when incoming
 633          *  and has to be unmasked)
 634          *
 635          * We ignore the possibility of extension data because we don't
 636          * negotiate any extensions at the moment.
 637          *
 638          *    0                   1                   2                   3
 639          *    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
 640          *   +-+-+-+-+-------+-+-------------+-------------------------------+
 641          *   |F|R|R|R| opcode|R| Payload len |    Extended payload length    |
 642          *   |I|S|S|S|  (4)  |S|     (7)     |             (16/63)           |
 643          *   |N|V|V|V|       |V|             |   (if payload len==126/127)   |
 644          *   | |1|2|3|       |4|             |                               |
 645          *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 646          *   |     Extended payload length continued, if payload len == 127  |
 647          *   + - - - - - - - - - - - - - - - +-------------------------------+
 648          *   |                               |         Extension data        |
 649          *   +-------------------------------+ - - - - - - - - - - - - - - - +
 650          *   :                                                               :
 651          *   +---------------------------------------------------------------+
 652          *   :                       Application data                        :
 653          *   +---------------------------------------------------------------+
 654          *
 655          *  We pass payload through to userland as soon as we get it, ignoring
 656          *  FIN.  It's up to userland to buffer it up if it wants to see a
 657          *  whole unfragmented block of the original size (which may be up to
 658          *  2^63 long!)
 659          */
 660
 661         case LWS_RXPS_04_FRAME_HDR_1:
 662 handle_first:
 663
 664                 wsi->u.ws.opcode = c & 0xf;
 665                 wsi->u.ws.rsv = c & 0x70;
 666                 wsi->u.ws.final = !!((c >> 7) & 1);
 667
 668                 switch (wsi->u.ws.opcode) {
 669                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 670                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 671                         wsi->u.ws.frame_is_binary =
 672                              wsi->u.ws.opcode == LWS_WS_OPCODE_07__BINARY_FRAME;
 673                         break;
 674                 }
 675                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN;
 676                 break;
 677
 678         case LWS_RXPS_04_FRAME_HDR_LEN:
 679
 680                 wsi->u.ws.this_frame_masked = !!(c & 0x80);
 681
 682                 switch (c & 0x7f) {
 683                 case 126:
 684                         /* control frames are not allowed to have big lengths */
 685                         if (wsi->u.ws.opcode & 8)
 686                                 goto illegal_ctl_length;
 687
 688                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2;
 689                         break;
 690                 case 127:
 691                         /* control frames are not allowed to have big lengths */
 692                         if (wsi->u.ws.opcode & 8)
 693                                 goto illegal_ctl_length;
 694
 695                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8;
 696                         break;
 697                 default:
 698                         wsi->u.ws.rx_packet_length = c & 0x7f;
 699                         if (wsi->u.ws.this_frame_masked)
 700                                 wsi->lws_rx_parse_state =
 701                                                 LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 702                         else
 703                                 if (wsi->u.ws.rx_packet_length)
 704                                         wsi->lws_rx_parse_state =
 705                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 706                                 else {
 707                                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 708                                         goto spill;
 709                                 }
 710                         break;
 711                 }
 712                 break;
 713
 714         case LWS_RXPS_04_FRAME_HDR_LEN16_2:
 715                 wsi->u.ws.rx_packet_length = c << 8;
 716                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1;
 717                 break;
 718
 719         case LWS_RXPS_04_FRAME_HDR_LEN16_1:
 720                 wsi->u.ws.rx_packet_length |= c;
 721                 if (wsi->u.ws.this_frame_masked)
 722                         wsi->lws_rx_parse_state =
 723                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 724                 else
 725                         wsi->lws_rx_parse_state =
 726                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 727                 break;
 728
 729         case LWS_RXPS_04_FRAME_HDR_LEN64_8:
 730                 if (c & 0x80) {
 731                         lwsl_warn("b63 of length must be zero\n");
 732                         /* kill the connection */
 733                         return -1;
 734                 }
 735 #if defined __LP64__
 736                 wsi->u.ws.rx_packet_length = ((size_t)c) << 56;
 737 #else
 738                 wsi->u.ws.rx_packet_length = 0;
 739 #endif
 740                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7;
 741                 break;
 742
 743         case LWS_RXPS_04_FRAME_HDR_LEN64_7:
 744 #if defined __LP64__
 745                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 48;
 746 #endif
 747                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6;
 748                 break;
 749
 750         case LWS_RXPS_04_FRAME_HDR_LEN64_6:
 751 #if defined __LP64__
 752                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 40;
 753 #endif
 754                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5;
 755                 break;
 756
 757         case LWS_RXPS_04_FRAME_HDR_LEN64_5:
 758 #if defined __LP64__
 759                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 32;
 760 #endif
 761                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4;
 762                 break;
 763
 764         case LWS_RXPS_04_FRAME_HDR_LEN64_4:
 765                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 24;
 766                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3;
 767                 break;
 768
 769         case LWS_RXPS_04_FRAME_HDR_LEN64_3:
 770                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 16;
 771                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2;
 772                 break;
 773
 774         case LWS_RXPS_04_FRAME_HDR_LEN64_2:
 775                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 8;
 776                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1;
 777                 break;
 778
 779         case LWS_RXPS_04_FRAME_HDR_LEN64_1:
 780                 wsi->u.ws.rx_packet_length |= ((size_t)c);
 781                 if (wsi->u.ws.this_frame_masked)
 782                         wsi->lws_rx_parse_state =
 783                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 784                 else
 785                         wsi->lws_rx_parse_state =
 786                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 787                 break;
 788
 789         case LWS_RXPS_07_COLLECT_FRAME_KEY_1:
 790                 wsi->u.ws.frame_masking_nonce_04[0] = c;
 791                 if (c)
 792                         wsi->u.ws.all_zero_nonce = 0;
 793                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2;
 794                 break;
 795
 796         case LWS_RXPS_07_COLLECT_FRAME_KEY_2:
 797                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 798                 if (c)
 799                         wsi->u.ws.all_zero_nonce = 0;
 800                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3;
 801                 break;
 802
 803         case LWS_RXPS_07_COLLECT_FRAME_KEY_3:
 804                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 805                 if (c)
 806                         wsi->u.ws.all_zero_nonce = 0;
 807                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4;
 808                 break;
 809
 810         case LWS_RXPS_07_COLLECT_FRAME_KEY_4:
 811                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 812                 if (c)
 813                         wsi->u.ws.all_zero_nonce = 0;
 814                 wsi->lws_rx_parse_state =
 815                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 816                 wsi->u.ws.frame_mask_index = 0;
 817                 if (wsi->u.ws.rx_packet_length == 0) {
 818                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 819                         goto spill;
 820                 }
 821                 break;
 822
 823
 824         case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
 825
 826                 if (!wsi->u.ws.rx_user_buffer) {
 827                         lwsl_err("NULL user buffer...\n");
 828                         return 1;
 829                 }
 830
 831                 if (wsi->u.ws.all_zero_nonce)
 832                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 833                                (wsi->u.ws.rx_user_buffer_head++)] = c;
 834                 else
 835                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 836                                (wsi->u.ws.rx_user_buffer_head++)] =
 837                                    c ^ wsi->u.ws.frame_masking_nonce_04[
 838                                             (wsi->u.ws.frame_mask_index++) & 3];
 839
 840                 if (--wsi->u.ws.rx_packet_length == 0) {
 841                         /* spill because we have the whole frame */
 842                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 843                         goto spill;
 844                 }
 845
 846                 /*
 847                  * if there's no protocol max frame size given, we are
 848                  * supposed to default to LWS_MAX_SOCKET_IO_BUF
 849                  */
 850
 851                 if (!wsi->protocol->rx_buffer_size &&
 852                                         wsi->u.ws.rx_user_buffer_head !=
 853                                                           LWS_MAX_SOCKET_IO_BUF)
 854                         break;
 855                 else
 856                         if (wsi->protocol->rx_buffer_size &&
 857                                         wsi->u.ws.rx_user_buffer_head !=
 858                                                   wsi->protocol->rx_buffer_size)
 859                         break;
 860
 861                 /* spill because we filled our rx buffer */
 862 spill:
 863                 /*
 864                  * is this frame a control packet we should take care of at this
 865                  * layer?  If so service it and hide it from the user callback
 866                  */
 867
 868                 lwsl_parser("spill on %s\n", wsi->protocol->name);
 869
 870                 switch (wsi->u.ws.opcode) {
 871                 case LWS_WS_OPCODE_07__CLOSE:
 872                         /* is this an acknowledgement of our close? */
 873                         if (wsi->state == WSI_STATE_AWAITING_CLOSE_ACK) {
 874                                 /*
 875                                  * fine he has told us he is closing too, let's
 876                                  * finish our close
 877                                  */
 878                                 lwsl_parser("seen client close ack\n");
 879                                 return -1;
 880                         }
 881                         if (wsi->state == WSI_STATE_RETURNED_CLOSE_ALREADY)
 882                                 /* if he sends us 2 CLOSE, kill him */
 883                                 return -1;
 884
 885                         lwsl_parser("server sees client close packet\n");
 886                         wsi->state = WSI_STATE_RETURNED_CLOSE_ALREADY;
 887                         /* deal with the close packet contents as a PONG */
 888                         wsi->u.ws.payload_is_close = 1;
 889                         goto process_as_ping;
 890
 891                 case LWS_WS_OPCODE_07__PING:
 892                         lwsl_info("received %d byte ping, sending pong\n",
 893                                                  wsi->u.ws.rx_user_buffer_head);
 894
 895                         if (wsi->u.ws.ping_pending_flag) {
 896                                 /*
 897                                  * there is already a pending ping payload
 898                                  * we should just log and drop
 899                                  */
 900                                 lwsl_parser("DROP PING since one pending\n");
 901                                 goto ping_drop;
 902                         }
 903 process_as_ping:
 904                         /* control packets can only be < 128 bytes long */
 905                         if (wsi->u.ws.rx_user_buffer_head > 128 - 4) {
 906                                 lwsl_parser("DROP PING payload too large\n");
 907                                 goto ping_drop;
 908                         }
 909
 910                         /* if existing buffer is too small, drop it */
 911                         if (wsi->u.ws.ping_payload_buf &&
 912                             wsi->u.ws.ping_payload_alloc < wsi->u.ws.rx_user_buffer_head) {
 913                                 lws_free2(wsi->u.ws.ping_payload_buf);
 914                         }
 915
 916                         /* if no buffer, allocate it */
 917                         if (!wsi->u.ws.ping_payload_buf) {
 918                                 wsi->u.ws.ping_payload_buf = lws_malloc(wsi->u.ws.rx_user_buffer_head
 919                                                                         + LWS_SEND_BUFFER_PRE_PADDING);
 920                                 wsi->u.ws.ping_payload_alloc = wsi->u.ws.rx_user_buffer_head;
 921                         }
 922
 923                         /* stash the pong payload */
 924                         memcpy(wsi->u.ws.ping_payload_buf + LWS_SEND_BUFFER_PRE_PADDING,
 925                                &wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
 926                                 wsi->u.ws.rx_user_buffer_head);
 927
 928                         wsi->u.ws.ping_payload_len = wsi->u.ws.rx_user_buffer_head;
 929                         wsi->u.ws.ping_pending_flag = 1;
 930
 931                         /* get it sent as soon as possible */
 932                         libwebsocket_callback_on_writable(wsi->protocol->owning_server, wsi);
 933 ping_drop:
 934                         wsi->u.ws.rx_user_buffer_head = 0;
 935                         return 0;
 936
 937                 case LWS_WS_OPCODE_07__PONG:
 938                         lwsl_info("received pong\n");
 939                         lwsl_hexdump(&wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
 940                                      wsi->u.ws.rx_user_buffer_head);
 941
 942                         /* issue it */
 943                         callback_action = LWS_CALLBACK_RECEIVE_PONG;
 944                         break;
 945
 946                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 947                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 948                 case LWS_WS_OPCODE_07__CONTINUATION:
 949                         break;
 950
 951                 default:
 952                         lwsl_parser("passing opc %x up to exts\n",
 953                                                         wsi->u.ws.opcode);
 954                         /*
 955                          * It's something special we can't understand here.
 956                          * Pass the payload up to the extension's parsing
 957                          * state machine.
 958                          */
 959
 960                         eff_buf.token = &wsi->u.ws.rx_user_buffer[
 961                                                    LWS_SEND_BUFFER_PRE_PADDING];
 962                         eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 963
 964                         if (lws_ext_callback_for_each_active(wsi,
 965                                 LWS_EXT_CALLBACK_EXTENDED_PAYLOAD_RX,
 966                                         &eff_buf, 0) <= 0) /* not handle or fail */
 967                                 lwsl_ext("ext opc opcode 0x%x unknown\n",
 968                                                               wsi->u.ws.opcode);
 969
 970                         wsi->u.ws.rx_user_buffer_head = 0;
 971                         return 0;
 972                 }
 973
 974                 /*
 975                  * No it's real payload, pass it up to the user callback.
 976                  * It's nicely buffered with the pre-padding taken care of
 977                  * so it can be sent straight out again using libwebsocket_write
 978                  */
 979
 980                 eff_buf.token = &wsi->u.ws.rx_user_buffer[
 981                                                 LWS_SEND_BUFFER_PRE_PADDING];
 982                 eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 983
 984                 if (lws_ext_callback_for_each_active(wsi,
 985                                 LWS_EXT_CALLBACK_PAYLOAD_RX, &eff_buf, 0) < 0)
 986                         return -1;
 987
 988                 if (eff_buf.token_len > 0) {
 989                         eff_buf.token[eff_buf.token_len] = '\0';
 990
 991                         if (wsi->protocol->callback) {
 992
 993                                 if (callback_action == LWS_CALLBACK_RECEIVE_PONG)
 994                                     lwsl_info("Doing pong callback\n");
 995
 996                                 ret = user_callback_handle_rxflow(
 997                                                 wsi->protocol->callback,
 998                                                 wsi->protocol->owning_server,
 999                                                 wsi,
1000                                                 (enum libwebsocket_callback_reasons)callback_action,
1001                                                 wsi->user_space,
1002                                                 eff_buf.token,
1003                                                 eff_buf.token_len);
1004                         }
1005                         else
1006                                 lwsl_err("No callback on payload spill!\n");
1007                 }
1008
1009                 wsi->u.ws.rx_user_buffer_head = 0;
1010                 break;
1011         }
1012
1013         return ret;
1014
1015 illegal_ctl_length:
1016
1017         lwsl_warn("Control frame with xtended length is illegal\n");
1018         /* kill the connection */
1019         return -1;
1020 }
1021
1022
1023 /**
1024  * libwebsockets_remaining_packet_payload() - Bytes to come before "overall"
1025  *                                            rx packet is complete
1026  * @wsi:                Websocket instance (available from user callback)
1027  *
1028  *      This function is intended to be called from the callback if the
1029  *  user code is interested in "complete packets" from the client.
1030  *  libwebsockets just passes through payload as it comes and issues a buffer
1031  *  additionally when it hits a built-in limit.  The LWS_CALLBACK_RECEIVE
1032  *  callback handler can use this API to find out if the buffer it has just
1033  *  been given is the last piece of a "complete packet" from the client --
1034  *  when that is the case libwebsockets_remaining_packet_payload() will return
1035  *  0.
1036  *
1037  *  Many protocols won't care becuse their packets are always small.
1038  */
1039
1040 LWS_VISIBLE size_t
1041 libwebsockets_remaining_packet_payload(struct libwebsocket *wsi)
1042 {
1043         return wsi->u.ws.rx_packet_length;
1044 }