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 lws *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 lws *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 lws *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 lws *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 lws *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 lws *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 lws *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 lws_parse(struct lws_context *context, struct lws *wsi, unsigned char c)
 210 {
 211         static const unsigned char methods[] = {
 212                 WSI_TOKEN_GET_URI,
 213                 WSI_TOKEN_POST_URI,
 214                 WSI_TOKEN_OPTIONS_URI,
 215                 WSI_TOKEN_PUT_URI,
 216                 WSI_TOKEN_PATCH_URI,
 217                 WSI_TOKEN_DELETE_URI,
 218         };
 219         unsigned int n, m;
 220
 221         switch (wsi->u.hdr.parser_state) {
 222         default:
 223
 224                 lwsl_parser("WSI_TOK_(%d) '%c'\n", wsi->u.hdr.parser_state, c);
 225
 226                 /* collect into malloc'd buffers */
 227                 /* optional initial space swallow */
 228                 if (!wsi->u.hdr.ah->frags[wsi->u.hdr.ah->frag_index[
 229                                       wsi->u.hdr.parser_state]].len && c == ' ')
 230                         break;
 231
 232                 for (m = 0; m < ARRAY_SIZE(methods); m++)
 233                         if (wsi->u.hdr.parser_state == methods[m])
 234                                 break;
 235                 if (m == ARRAY_SIZE(methods))
 236                         /* it was not any of the methods */
 237                         goto check_eol;
 238
 239                 /* special URI processing... end at space */
 240
 241                 if (c == ' ') {
 242                         /* enforce starting with / */
 243                         if (!wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len)
 244                                 if (issue_char(wsi, '/') < 0)
 245                                         return -1;
 246
 247                         /* begin parsing HTTP version: */
 248                         if (issue_char(wsi, '\0') < 0)
 249                                 return -1;
 250                         wsi->u.hdr.parser_state = WSI_TOKEN_HTTP;
 251                         goto start_fragment;
 252                 }
 253
 254                 /* special URI processing... convert %xx */
 255
 256                 switch (wsi->u.hdr.ues) {
 257                 case URIES_IDLE:
 258                         if (c == '%') {
 259                                 wsi->u.hdr.ues = URIES_SEEN_PERCENT;
 260                                 goto swallow;
 261                         }
 262                         break;
 263                 case URIES_SEEN_PERCENT:
 264                         if (char_to_hex(c) < 0) {
 265                                 /* regurgitate */
 266                                 if (issue_char(wsi, '%') < 0)
 267                                         return -1;
 268                                 wsi->u.hdr.ues = URIES_IDLE;
 269                                 /* continue on to assess c */
 270                                 break;
 271                         }
 272                         wsi->u.hdr.esc_stash = c;
 273                         wsi->u.hdr.ues = URIES_SEEN_PERCENT_H1;
 274                         goto swallow;
 275
 276                 case URIES_SEEN_PERCENT_H1:
 277                         if (char_to_hex(c) < 0) {
 278                                 /* regurgitate */
 279                                 issue_char(wsi, '%');
 280                                 wsi->u.hdr.ues = URIES_IDLE;
 281                                 /* regurgitate + assess */
 282                                 if (lws_parse(context, wsi, wsi->u.hdr.esc_stash) < 0)
 283                                         return -1;
 284                                 /* continue on to assess c */
 285                                 break;
 286                         }
 287                         c = (char_to_hex(wsi->u.hdr.esc_stash) << 4) |
 288                                         char_to_hex(c);
 289                         wsi->u.hdr.ues = URIES_IDLE;
 290                         break;
 291                 }
 292
 293                 /*
 294                  * special URI processing...
 295                  *  convert /.. or /... or /../ etc to /
 296                  *  convert /./ to /
 297                  *  convert // or /// etc to /
 298                  *  leave /.dir or whatever alone
 299                  */
 300
 301                 switch (wsi->u.hdr.ups) {
 302                 case URIPS_IDLE:
 303                         /* issue the first / always */
 304                         if (c == '/')
 305                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 306                         break;
 307                 case URIPS_SEEN_SLASH:
 308                         /* swallow subsequent slashes */
 309                         if (c == '/')
 310                                 goto swallow;
 311                         /* track and swallow the first . after / */
 312                         if (c == '.') {
 313                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT;
 314                                 goto swallow;
 315                         }
 316                         wsi->u.hdr.ups = URIPS_IDLE;
 317                         break;
 318                 case URIPS_SEEN_SLASH_DOT:
 319                         /* swallow second . */
 320                         if (c == '.') {
 321                                 /*
 322                                  * back up one dir level if possible
 323                                  * safe against header fragmentation because
 324                                  * the method URI can only be in 1 fragment
 325                                  */
 326                                 if (wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len > 2) {
 327                                         wsi->u.hdr.ah->pos--;
 328                                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len--;
 329                                         do {
 330                                                 wsi->u.hdr.ah->pos--;
 331                                                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len--;
 332                                         } while (wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len > 1 &&
 333                                                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos] != '/');
 334                                 }
 335                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT_DOT;
 336                                 goto swallow;
 337                         }
 338                         /* change /./ to / */
 339                         if (c == '/') {
 340                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 341                                 goto swallow;
 342                         }
 343                         /* it was like /.dir ... regurgitate the . */
 344                         wsi->u.hdr.ups = URIPS_IDLE;
 345                         issue_char(wsi, '.');
 346                         break;
 347
 348                 case URIPS_SEEN_SLASH_DOT_DOT:
 349                         /* swallow prior .. chars and any subsequent . */
 350                         if (c == '.')
 351                                 goto swallow;
 352                         /* last issued was /, so another / == // */
 353                         if (c == '/')
 354                                 goto swallow;
 355                         /* last we issued was / so SEEN_SLASH */
 356                         wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 357                         break;
 358                 case URIPS_ARGUMENTS:
 359                         /* leave them alone */
 360                         break;
 361                 }
 362
 363                 if (c == '?') { /* start of URI arguments */
 364                         /* seal off uri header */
 365                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 366
 367                         /* move to using WSI_TOKEN_HTTP_URI_ARGS */
 368                         wsi->u.hdr.ah->next_frag_index++;
 369                         wsi->u.hdr.ah->frags[
 370                                 wsi->u.hdr.ah->next_frag_index].offset =
 371                                                              wsi->u.hdr.ah->pos;
 372                         wsi->u.hdr.ah->frags[
 373                                         wsi->u.hdr.ah->next_frag_index].len = 0;
 374                         wsi->u.hdr.ah->frags[
 375                             wsi->u.hdr.ah->next_frag_index].next_frag_index = 0;
 376
 377                         wsi->u.hdr.ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS] =
 378                                                  wsi->u.hdr.ah->next_frag_index;
 379
 380                         /* defeat normal uri path processing */
 381                         wsi->u.hdr.ups = URIPS_ARGUMENTS;
 382                         goto swallow;
 383                 }
 384
 385 check_eol:
 386
 387                 /* bail at EOL */
 388                 if (wsi->u.hdr.parser_state != WSI_TOKEN_CHALLENGE &&
 389                                                                   c == '\x0d') {
 390                         c = '\0';
 391                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 392                         lwsl_parser("*\n");
 393                 }
 394
 395                 n = issue_char(wsi, c);
 396                 if ((int)n < 0)
 397                         return -1;
 398                 if (n > 0)
 399                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 400
 401 swallow:
 402                 /* per-protocol end of headers management */
 403
 404                 if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 405                         goto set_parsing_complete;
 406                 break;
 407
 408                 /* collecting and checking a name part */
 409         case WSI_TOKEN_NAME_PART:
 410                 lwsl_parser("WSI_TOKEN_NAME_PART '%c' (mode=%d)\n", c, wsi->mode);
 411
 412                 wsi->u.hdr.lextable_pos =
 413                                 lextable_decode(wsi->u.hdr.lextable_pos, c);
 414                 /*
 415                  * Server needs to look out for unknown methods...
 416                  */
 417                 if (wsi->u.hdr.lextable_pos < 0 &&
 418                     wsi->mode == LWS_CONNMODE_HTTP_SERVING) {
 419                         /* this is not a header we know about */
 420                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 421                                 if (wsi->u.hdr.ah->frag_index[methods[m]]) {
 422                                         /*
 423                                          * already had the method, no idea what
 424                                          * this crap from the client is, ignore
 425                                          */
 426                                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 427                                         break;
 428                                 }
 429                         /*
 430                          * hm it's an unknown http method from a client in fact,
 431                          * treat as dangerous
 432                          */
 433                         if (m == ARRAY_SIZE(methods)) {
 434                                 lwsl_info("Unknown method - dropping\n");
 435                                 return -1;
 436                         }
 437                         break;
 438                 }
 439                 /*
 440                  * ...otherwise for a client, let him ignore unknown headers
 441                  * coming from the server
 442                  */
 443                 if (wsi->u.hdr.lextable_pos < 0) {
 444                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 445                         break;
 446                 }
 447
 448                 if (lextable[wsi->u.hdr.lextable_pos] < FAIL_CHAR) {
 449                         /* terminal state */
 450
 451                         n = ((unsigned int)lextable[wsi->u.hdr.lextable_pos] << 8) |
 452                                         lextable[wsi->u.hdr.lextable_pos + 1];
 453
 454                         lwsl_parser("known hdr %d\n", n);
 455                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 456                                 if (n == methods[m] &&
 457                                                 wsi->u.hdr.ah->frag_index[
 458                                                         methods[m]]) {
 459                                         lwsl_warn("Duplicated method\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                         else
 477                                 wsi->u.hdr.current_token_limit = sizeof(wsi->u.hdr.ah->data);
 478
 479                         if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 480                                 goto set_parsing_complete;
 481
 482                         goto start_fragment;
 483                 }
 484                 break;
 485
 486 start_fragment:
 487                 wsi->u.hdr.ah->next_frag_index++;
 488                 if (wsi->u.hdr.ah->next_frag_index ==
 489                                 sizeof(wsi->u.hdr.ah->frags) /
 490                                               sizeof(wsi->u.hdr.ah->frags[0])) {
 491                         lwsl_warn("More hdr frags than we can deal with\n");
 492                         return -1;
 493                 }
 494
 495                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].offset =
 496                                                              wsi->u.hdr.ah->pos;
 497                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len = 0;
 498                 wsi->u.hdr.ah->frags[
 499                             wsi->u.hdr.ah->next_frag_index].next_frag_index = 0;
 500
 501                 n = wsi->u.hdr.ah->frag_index[wsi->u.hdr.parser_state];
 502                 if (!n) { /* first fragment */
 503                         wsi->u.hdr.ah->frag_index[wsi->u.hdr.parser_state] =
 504                                                  wsi->u.hdr.ah->next_frag_index;
 505                         break;
 506                 }
 507                 /* continuation */
 508                 while (wsi->u.hdr.ah->frags[n].next_frag_index)
 509                                 n = wsi->u.hdr.ah->frags[n].next_frag_index;
 510                 wsi->u.hdr.ah->frags[n].next_frag_index =
 511                                                  wsi->u.hdr.ah->next_frag_index;
 512
 513                 if (wsi->u.hdr.ah->pos == sizeof(wsi->u.hdr.ah->data)) {
 514                         lwsl_warn("excessive header content\n");
 515                         return -1;
 516                 }
 517
 518                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = ' ';
 519                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len++;
 520                 break;
 521
 522                 /* skipping arg part of a name we didn't recognize */
 523         case WSI_TOKEN_SKIPPING:
 524                 lwsl_parser("WSI_TOKEN_SKIPPING '%c'\n", c);
 525
 526                 if (c == '\x0d')
 527                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 528                 break;
 529
 530         case WSI_TOKEN_SKIPPING_SAW_CR:
 531                 lwsl_parser("WSI_TOKEN_SKIPPING_SAW_CR '%c'\n", c);
 532                 if (c == '\x0a') {
 533                         wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 534                         wsi->u.hdr.lextable_pos = 0;
 535                 } else
 536                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 537                 break;
 538                 /* we're done, ignore anything else */
 539
 540         case WSI_PARSING_COMPLETE:
 541                 lwsl_parser("WSI_PARSING_COMPLETE '%c'\n", c);
 542                 break;
 543         }
 544
 545         return 0;
 546
 547 set_parsing_complete:
 548
 549         if (lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE)) {
 550                 if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION))
 551                         wsi->ietf_spec_revision =
 552                                atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION));
 553
 554                 lwsl_parser("v%02d hdrs completed\n", wsi->ietf_spec_revision);
 555         }
 556         wsi->u.hdr.parser_state = WSI_PARSING_COMPLETE;
 557         wsi->hdr_parsing_completed = 1;
 558
 559         return 0;
 560 }
 561
 562
 563 /**
 564  * lws_frame_is_binary: true if the current frame was sent in binary mode
 565  *
 566  * @wsi: the connection we are inquiring about
 567  *
 568  * This is intended to be called from the LWS_CALLBACK_RECEIVE callback if
 569  * it's interested to see if the frame it's dealing with was sent in binary
 570  * mode.
 571  */
 572
 573 LWS_VISIBLE int lws_frame_is_binary(struct lws *wsi)
 574 {
 575         return wsi->u.ws.frame_is_binary;
 576 }
 577
 578 int
 579 lws_rx_sm(struct lws *wsi, unsigned char c)
 580 {
 581         struct lws_tokens eff_buf;
 582         int ret = 0;
 583         int callback_action = LWS_CALLBACK_RECEIVE;
 584
 585         switch (wsi->lws_rx_parse_state) {
 586         case LWS_RXPS_NEW:
 587
 588                 switch (wsi->ietf_spec_revision) {
 589                 case 13:
 590                         /*
 591                          * no prepended frame key any more
 592                          */
 593                         wsi->u.ws.all_zero_nonce = 1;
 594                         goto handle_first;
 595
 596                 default:
 597                         lwsl_warn("lws_rx_sm: unknown spec version %d\n",
 598                                                        wsi->ietf_spec_revision);
 599                         break;
 600                 }
 601                 break;
 602         case LWS_RXPS_04_MASK_NONCE_1:
 603                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 604                 if (c)
 605                         wsi->u.ws.all_zero_nonce = 0;
 606                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_2;
 607                 break;
 608         case LWS_RXPS_04_MASK_NONCE_2:
 609                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 610                 if (c)
 611                         wsi->u.ws.all_zero_nonce = 0;
 612                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_3;
 613                 break;
 614         case LWS_RXPS_04_MASK_NONCE_3:
 615                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 616                 if (c)
 617                         wsi->u.ws.all_zero_nonce = 0;
 618
 619                 /*
 620                  * start from the zero'th byte in the XOR key buffer since
 621                  * this is the start of a frame with a new key
 622                  */
 623
 624                 wsi->u.ws.frame_mask_index = 0;
 625
 626                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
 627                 break;
 628
 629         /*
 630          *  04 logical framing from the spec (all this is masked when incoming
 631          *  and has to be unmasked)
 632          *
 633          * We ignore the possibility of extension data because we don't
 634          * negotiate any extensions at the moment.
 635          *
 636          *    0                   1                   2                   3
 637          *    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
 638          *   +-+-+-+-+-------+-+-------------+-------------------------------+
 639          *   |F|R|R|R| opcode|R| Payload len |    Extended payload length    |
 640          *   |I|S|S|S|  (4)  |S|     (7)     |             (16/63)           |
 641          *   |N|V|V|V|       |V|             |   (if payload len==126/127)   |
 642          *   | |1|2|3|       |4|             |                               |
 643          *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 644          *   |     Extended payload length continued, if payload len == 127  |
 645          *   + - - - - - - - - - - - - - - - +-------------------------------+
 646          *   |                               |         Extension data        |
 647          *   +-------------------------------+ - - - - - - - - - - - - - - - +
 648          *   :                                                               :
 649          *   +---------------------------------------------------------------+
 650          *   :                       Application data                        :
 651          *   +---------------------------------------------------------------+
 652          *
 653          *  We pass payload through to userland as soon as we get it, ignoring
 654          *  FIN.  It's up to userland to buffer it up if it wants to see a
 655          *  whole unfragmented block of the original size (which may be up to
 656          *  2^63 long!)
 657          */
 658
 659         case LWS_RXPS_04_FRAME_HDR_1:
 660 handle_first:
 661
 662                 wsi->u.ws.opcode = c & 0xf;
 663                 wsi->u.ws.rsv = c & 0x70;
 664                 wsi->u.ws.final = !!((c >> 7) & 1);
 665
 666                 switch (wsi->u.ws.opcode) {
 667                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 668                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 669                         wsi->u.ws.frame_is_binary =
 670                              wsi->u.ws.opcode == LWS_WS_OPCODE_07__BINARY_FRAME;
 671                         break;
 672                 }
 673                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN;
 674                 break;
 675
 676         case LWS_RXPS_04_FRAME_HDR_LEN:
 677
 678                 wsi->u.ws.this_frame_masked = !!(c & 0x80);
 679
 680                 switch (c & 0x7f) {
 681                 case 126:
 682                         /* control frames are not allowed to have big lengths */
 683                         if (wsi->u.ws.opcode & 8)
 684                                 goto illegal_ctl_length;
 685
 686                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2;
 687                         break;
 688                 case 127:
 689                         /* control frames are not allowed to have big lengths */
 690                         if (wsi->u.ws.opcode & 8)
 691                                 goto illegal_ctl_length;
 692
 693                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8;
 694                         break;
 695                 default:
 696                         wsi->u.ws.rx_packet_length = c & 0x7f;
 697                         if (wsi->u.ws.this_frame_masked)
 698                                 wsi->lws_rx_parse_state =
 699                                                 LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 700                         else
 701                                 if (wsi->u.ws.rx_packet_length)
 702                                         wsi->lws_rx_parse_state =
 703                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 704                                 else {
 705                                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 706                                         goto spill;
 707                                 }
 708                         break;
 709                 }
 710                 break;
 711
 712         case LWS_RXPS_04_FRAME_HDR_LEN16_2:
 713                 wsi->u.ws.rx_packet_length = c << 8;
 714                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1;
 715                 break;
 716
 717         case LWS_RXPS_04_FRAME_HDR_LEN16_1:
 718                 wsi->u.ws.rx_packet_length |= c;
 719                 if (wsi->u.ws.this_frame_masked)
 720                         wsi->lws_rx_parse_state =
 721                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 722                 else
 723                         wsi->lws_rx_parse_state =
 724                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 725                 break;
 726
 727         case LWS_RXPS_04_FRAME_HDR_LEN64_8:
 728                 if (c & 0x80) {
 729                         lwsl_warn("b63 of length must be zero\n");
 730                         /* kill the connection */
 731                         return -1;
 732                 }
 733 #if defined __LP64__
 734                 wsi->u.ws.rx_packet_length = ((size_t)c) << 56;
 735 #else
 736                 wsi->u.ws.rx_packet_length = 0;
 737 #endif
 738                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7;
 739                 break;
 740
 741         case LWS_RXPS_04_FRAME_HDR_LEN64_7:
 742 #if defined __LP64__
 743                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 48;
 744 #endif
 745                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6;
 746                 break;
 747
 748         case LWS_RXPS_04_FRAME_HDR_LEN64_6:
 749 #if defined __LP64__
 750                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 40;
 751 #endif
 752                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5;
 753                 break;
 754
 755         case LWS_RXPS_04_FRAME_HDR_LEN64_5:
 756 #if defined __LP64__
 757                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 32;
 758 #endif
 759                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4;
 760                 break;
 761
 762         case LWS_RXPS_04_FRAME_HDR_LEN64_4:
 763                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 24;
 764                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3;
 765                 break;
 766
 767         case LWS_RXPS_04_FRAME_HDR_LEN64_3:
 768                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 16;
 769                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2;
 770                 break;
 771
 772         case LWS_RXPS_04_FRAME_HDR_LEN64_2:
 773                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 8;
 774                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1;
 775                 break;
 776
 777         case LWS_RXPS_04_FRAME_HDR_LEN64_1:
 778                 wsi->u.ws.rx_packet_length |= ((size_t)c);
 779                 if (wsi->u.ws.this_frame_masked)
 780                         wsi->lws_rx_parse_state =
 781                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 782                 else
 783                         wsi->lws_rx_parse_state =
 784                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 785                 break;
 786
 787         case LWS_RXPS_07_COLLECT_FRAME_KEY_1:
 788                 wsi->u.ws.frame_masking_nonce_04[0] = c;
 789                 if (c)
 790                         wsi->u.ws.all_zero_nonce = 0;
 791                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2;
 792                 break;
 793
 794         case LWS_RXPS_07_COLLECT_FRAME_KEY_2:
 795                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 796                 if (c)
 797                         wsi->u.ws.all_zero_nonce = 0;
 798                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3;
 799                 break;
 800
 801         case LWS_RXPS_07_COLLECT_FRAME_KEY_3:
 802                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 803                 if (c)
 804                         wsi->u.ws.all_zero_nonce = 0;
 805                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4;
 806                 break;
 807
 808         case LWS_RXPS_07_COLLECT_FRAME_KEY_4:
 809                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 810                 if (c)
 811                         wsi->u.ws.all_zero_nonce = 0;
 812                 wsi->lws_rx_parse_state =
 813                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 814                 wsi->u.ws.frame_mask_index = 0;
 815                 if (wsi->u.ws.rx_packet_length == 0) {
 816                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 817                         goto spill;
 818                 }
 819                 break;
 820
 821
 822         case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
 823
 824                 if (!wsi->u.ws.rx_user_buffer) {
 825                         lwsl_err("NULL user buffer...\n");
 826                         return 1;
 827                 }
 828
 829                 if (wsi->u.ws.all_zero_nonce)
 830                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 831                                (wsi->u.ws.rx_user_buffer_head++)] = c;
 832                 else
 833                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 834                                (wsi->u.ws.rx_user_buffer_head++)] =
 835                                    c ^ wsi->u.ws.frame_masking_nonce_04[
 836                                             (wsi->u.ws.frame_mask_index++) & 3];
 837
 838                 if (--wsi->u.ws.rx_packet_length == 0) {
 839                         /* spill because we have the whole frame */
 840                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 841                         goto spill;
 842                 }
 843
 844                 /*
 845                  * if there's no protocol max frame size given, we are
 846                  * supposed to default to LWS_MAX_SOCKET_IO_BUF
 847                  */
 848
 849                 if (!wsi->protocol->rx_buffer_size &&
 850                                         wsi->u.ws.rx_user_buffer_head !=
 851                                                           LWS_MAX_SOCKET_IO_BUF)
 852                         break;
 853                 else
 854                         if (wsi->protocol->rx_buffer_size &&
 855                                         wsi->u.ws.rx_user_buffer_head !=
 856                                                   wsi->protocol->rx_buffer_size)
 857                         break;
 858
 859                 /* spill because we filled our rx buffer */
 860 spill:
 861                 /*
 862                  * is this frame a control packet we should take care of at this
 863                  * layer?  If so service it and hide it from the user callback
 864                  */
 865
 866                 lwsl_parser("spill on %s\n", wsi->protocol->name);
 867
 868                 switch (wsi->u.ws.opcode) {
 869                 case LWS_WS_OPCODE_07__CLOSE:
 870                         /* is this an acknowledgement of our close? */
 871                         if (wsi->state == WSI_STATE_AWAITING_CLOSE_ACK) {
 872                                 /*
 873                                  * fine he has told us he is closing too, let's
 874                                  * finish our close
 875                                  */
 876                                 lwsl_parser("seen client close ack\n");
 877                                 return -1;
 878                         }
 879                         if (wsi->state == WSI_STATE_RETURNED_CLOSE_ALREADY)
 880                                 /* if he sends us 2 CLOSE, kill him */
 881                                 return -1;
 882
 883                         lwsl_parser("server sees client close packet\n");
 884                         wsi->state = WSI_STATE_RETURNED_CLOSE_ALREADY;
 885                         /* deal with the close packet contents as a PONG */
 886                         wsi->u.ws.payload_is_close = 1;
 887                         goto process_as_ping;
 888
 889                 case LWS_WS_OPCODE_07__PING:
 890                         lwsl_info("received %d byte ping, sending pong\n",
 891                                                  wsi->u.ws.rx_user_buffer_head);
 892
 893                         if (wsi->u.ws.ping_pending_flag) {
 894                                 /*
 895                                  * there is already a pending ping payload
 896                                  * we should just log and drop
 897                                  */
 898                                 lwsl_parser("DROP PING since one pending\n");
 899                                 goto ping_drop;
 900                         }
 901 process_as_ping:
 902                         /* control packets can only be < 128 bytes long */
 903                         if (wsi->u.ws.rx_user_buffer_head > 128 - 4) {
 904                                 lwsl_parser("DROP PING payload too large\n");
 905                                 goto ping_drop;
 906                         }
 907
 908                         /* if existing buffer is too small, drop it */
 909                         if (wsi->u.ws.ping_payload_buf &&
 910                             wsi->u.ws.ping_payload_alloc < wsi->u.ws.rx_user_buffer_head) {
 911                                 lws_free2(wsi->u.ws.ping_payload_buf);
 912                         }
 913
 914                         /* if no buffer, allocate it */
 915                         if (!wsi->u.ws.ping_payload_buf) {
 916                                 wsi->u.ws.ping_payload_buf = lws_malloc(wsi->u.ws.rx_user_buffer_head
 917                                                                         + LWS_SEND_BUFFER_PRE_PADDING);
 918                                 wsi->u.ws.ping_payload_alloc = wsi->u.ws.rx_user_buffer_head;
 919                         }
 920
 921                         /* stash the pong payload */
 922                         memcpy(wsi->u.ws.ping_payload_buf + LWS_SEND_BUFFER_PRE_PADDING,
 923                                &wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
 924                                 wsi->u.ws.rx_user_buffer_head);
 925
 926                         wsi->u.ws.ping_payload_len = wsi->u.ws.rx_user_buffer_head;
 927                         wsi->u.ws.ping_pending_flag = 1;
 928
 929                         /* get it sent as soon as possible */
 930                         lws_callback_on_writable(wsi->protocol->owning_server, wsi);
 931 ping_drop:
 932                         wsi->u.ws.rx_user_buffer_head = 0;
 933                         return 0;
 934
 935                 case LWS_WS_OPCODE_07__PONG:
 936                         lwsl_info("received pong\n");
 937                         lwsl_hexdump(&wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
 938                                      wsi->u.ws.rx_user_buffer_head);
 939
 940                         /* issue it */
 941                         callback_action = LWS_CALLBACK_RECEIVE_PONG;
 942                         break;
 943
 944                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 945                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 946                 case LWS_WS_OPCODE_07__CONTINUATION:
 947                         break;
 948
 949                 default:
 950                         lwsl_parser("passing opc %x up to exts\n",
 951                                                         wsi->u.ws.opcode);
 952                         /*
 953                          * It's something special we can't understand here.
 954                          * Pass the payload up to the extension's parsing
 955                          * state machine.
 956                          */
 957
 958                         eff_buf.token = &wsi->u.ws.rx_user_buffer[
 959                                                    LWS_SEND_BUFFER_PRE_PADDING];
 960                         eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 961
 962                         if (lws_ext_callback_for_each_active(wsi,
 963                                 LWS_EXT_CALLBACK_EXTENDED_PAYLOAD_RX,
 964                                         &eff_buf, 0) <= 0) /* not handle or fail */
 965                                 lwsl_ext("ext opc opcode 0x%x unknown\n",
 966                                                               wsi->u.ws.opcode);
 967
 968                         wsi->u.ws.rx_user_buffer_head = 0;
 969                         return 0;
 970                 }
 971
 972                 /*
 973                  * No it's real payload, pass it up to the user callback.
 974                  * It's nicely buffered with the pre-padding taken care of
 975                  * so it can be sent straight out again using lws_write
 976                  */
 977
 978                 eff_buf.token = &wsi->u.ws.rx_user_buffer[
 979                                                 LWS_SEND_BUFFER_PRE_PADDING];
 980                 eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 981
 982                 if (lws_ext_callback_for_each_active(wsi,
 983                                 LWS_EXT_CALLBACK_PAYLOAD_RX, &eff_buf, 0) < 0)
 984                         return -1;
 985
 986                 if (eff_buf.token_len > 0 ||
 987                     callback_action == LWS_CALLBACK_RECEIVE_PONG) {
 988                         eff_buf.token[eff_buf.token_len] = '\0';
 989
 990                         if (wsi->protocol->callback) {
 991
 992                                 if (callback_action == LWS_CALLBACK_RECEIVE_PONG)
 993                                     lwsl_info("Doing pong callback\n");
 994
 995                                 ret = user_callback_handle_rxflow(
 996                                                 wsi->protocol->callback,
 997                                                 wsi->protocol->owning_server,
 998                                                 wsi,
 999                                                 (enum lws_callback_reasons)callback_action,
1000                                                 wsi->user_space,
1001                                                 eff_buf.token,
1002                                                 eff_buf.token_len);
1003                         }
1004                         else
1005                                 lwsl_err("No callback on payload spill!\n");
1006                 }
1007
1008                 wsi->u.ws.rx_user_buffer_head = 0;
1009                 break;
1010         }
1011
1012         return ret;
1013
1014 illegal_ctl_length:
1015
1016         lwsl_warn("Control frame with xtended length is illegal\n");
1017         /* kill the connection */
1018         return -1;
1019 }
1020
1021
1022 /**
1023  * lws_remaining_packet_payload() - Bytes to come before "overall"
1024  *                                            rx packet is complete
1025  * @wsi:                Websocket instance (available from user callback)
1026  *
1027  *      This function is intended to be called from the callback if the
1028  *  user code is interested in "complete packets" from the client.
1029  *  libwebsockets just passes through payload as it comes and issues a buffer
1030  *  additionally when it hits a built-in limit.  The LWS_CALLBACK_RECEIVE
1031  *  callback handler can use this API to find out if the buffer it has just
1032  *  been given is the last piece of a "complete packet" from the client --
1033  *  when that is the case lws_remaining_packet_payload() will return
1034  *  0.
1035  *
1036  *  Many protocols won't care becuse their packets are always small.
1037  */
1038
1039 LWS_VISIBLE size_t
1040 lws_remaining_packet_payload(struct lws *wsi)
1041 {
1042         return wsi->u.ws.rx_packet_length;
1043 }