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, enc = 0;
 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                         enc = 1;
 290                         wsi->u.hdr.ues = URIES_IDLE;
 291                         break;
 292                 }
 293
 294                 /*
 295                  * special URI processing...
 296                  *  convert /.. or /... or /../ etc to /
 297                  *  convert /./ to /
 298                  *  convert // or /// etc to /
 299                  *  leave /.dir or whatever alone
 300                  */
 301
 302                 switch (wsi->u.hdr.ups) {
 303                 case URIPS_IDLE:
 304                         /* issue the first / always */
 305                         if (c == '/')
 306                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 307                         break;
 308                 case URIPS_SEEN_SLASH:
 309                         /* swallow subsequent slashes */
 310                         if (c == '/')
 311                                 goto swallow;
 312                         /* track and swallow the first . after / */
 313                         if (c == '.') {
 314                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT;
 315                                 goto swallow;
 316                         }
 317                         wsi->u.hdr.ups = URIPS_IDLE;
 318                         break;
 319                 case URIPS_SEEN_SLASH_DOT:
 320                         /* swallow second . */
 321                         if (c == '.') {
 322                                 /*
 323                                  * back up one dir level if possible
 324                                  * safe against header fragmentation because
 325                                  * the method URI can only be in 1 fragment
 326                                  */
 327                                 if (wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len > 2) {
 328                                         wsi->u.hdr.ah->pos--;
 329                                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len--;
 330                                         do {
 331                                                 wsi->u.hdr.ah->pos--;
 332                                                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len--;
 333                                         } while (wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len > 1 &&
 334                                                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos] != '/');
 335                                 }
 336                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT_DOT;
 337                                 goto swallow;
 338                         }
 339                         /* change /./ to / */
 340                         if (c == '/') {
 341                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 342                                 goto swallow;
 343                         }
 344                         /* it was like /.dir ... regurgitate the . */
 345                         wsi->u.hdr.ups = URIPS_IDLE;
 346                         issue_char(wsi, '.');
 347                         break;
 348
 349                 case URIPS_SEEN_SLASH_DOT_DOT:
 350                         /* swallow prior .. chars and any subsequent . */
 351                         if (c == '.')
 352                                 goto swallow;
 353                         /* last issued was /, so another / == // */
 354                         if (c == '/')
 355                                 goto swallow;
 356                         /* last we issued was / so SEEN_SLASH */
 357                         wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 358                         break;
 359                 case URIPS_ARGUMENTS:
 360                         /* leave them alone */
 361                         break;
 362                 }
 363
 364                 if (c == '?' && !enc) { /* start of URI arguments */
 365                         /* seal off uri header */
 366                         wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 367
 368                         /* move to using WSI_TOKEN_HTTP_URI_ARGS */
 369                         wsi->u.hdr.ah->next_frag_index++;
 370                         wsi->u.hdr.ah->frags[
 371                                 wsi->u.hdr.ah->next_frag_index].offset =
 372                                                              wsi->u.hdr.ah->pos;
 373                         wsi->u.hdr.ah->frags[
 374                                         wsi->u.hdr.ah->next_frag_index].len = 0;
 375                         wsi->u.hdr.ah->frags[
 376                             wsi->u.hdr.ah->next_frag_index].next_frag_index = 0;
 377
 378                         wsi->u.hdr.ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS] =
 379                                                  wsi->u.hdr.ah->next_frag_index;
 380
 381                         /* defeat normal uri path processing */
 382                         wsi->u.hdr.ups = URIPS_ARGUMENTS;
 383                         goto swallow;
 384                 }
 385
 386 check_eol:
 387
 388                 /* bail at EOL */
 389                 if (wsi->u.hdr.parser_state != WSI_TOKEN_CHALLENGE &&
 390                                                                   c == '\x0d') {
 391                         c = '\0';
 392                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 393                         lwsl_parser("*\n");
 394                 }
 395
 396                 n = issue_char(wsi, c);
 397                 if ((int)n < 0)
 398                         return -1;
 399                 if (n > 0)
 400                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 401
 402 swallow:
 403                 /* per-protocol end of headers management */
 404
 405                 if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 406                         goto set_parsing_complete;
 407                 break;
 408
 409                 /* collecting and checking a name part */
 410         case WSI_TOKEN_NAME_PART:
 411                 lwsl_parser("WSI_TOKEN_NAME_PART '%c' (mode=%d)\n", c, wsi->mode);
 412
 413                 wsi->u.hdr.lextable_pos =
 414                                 lextable_decode(wsi->u.hdr.lextable_pos, c);
 415                 /*
 416                  * Server needs to look out for unknown methods...
 417                  */
 418                 if (wsi->u.hdr.lextable_pos < 0 &&
 419                     wsi->mode == LWS_CONNMODE_HTTP_SERVING) {
 420                         /* this is not a header we know about */
 421                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 422                                 if (wsi->u.hdr.ah->frag_index[methods[m]]) {
 423                                         /*
 424                                          * already had the method, no idea what
 425                                          * this crap from the client is, ignore
 426                                          */
 427                                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 428                                         break;
 429                                 }
 430                         /*
 431                          * hm it's an unknown http method from a client in fact,
 432                          * treat as dangerous
 433                          */
 434                         if (m == ARRAY_SIZE(methods)) {
 435                                 lwsl_info("Unknown method - dropping\n");
 436                                 return -1;
 437                         }
 438                         break;
 439                 }
 440                 /*
 441                  * ...otherwise for a client, let him ignore unknown headers
 442                  * coming from the server
 443                  */
 444                 if (wsi->u.hdr.lextable_pos < 0) {
 445                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 446                         break;
 447                 }
 448
 449                 if (lextable[wsi->u.hdr.lextable_pos] < FAIL_CHAR) {
 450                         /* terminal state */
 451
 452                         n = ((unsigned int)lextable[wsi->u.hdr.lextable_pos] << 8) |
 453                                         lextable[wsi->u.hdr.lextable_pos + 1];
 454
 455                         lwsl_parser("known hdr %d\n", n);
 456                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 457                                 if (n == methods[m] &&
 458                                                 wsi->u.hdr.ah->frag_index[
 459                                                         methods[m]]) {
 460                                         lwsl_warn("Duplicated method\n");
 461                                         return -1;
 462                                 }
 463
 464                         /*
 465                          * WSORIGIN is protocol equiv to ORIGIN,
 466                          * JWebSocket likes to send it, map to ORIGIN
 467                          */
 468                         if (n == WSI_TOKEN_SWORIGIN)
 469                                 n = WSI_TOKEN_ORIGIN;
 470
 471                         wsi->u.hdr.parser_state = (enum lws_token_indexes)
 472                                                         (WSI_TOKEN_GET_URI + n);
 473
 474                         if (context->token_limits)
 475                                 wsi->u.hdr.current_token_limit =
 476                                         context->token_limits->token_limit[wsi->u.hdr.parser_state];
 477                         else
 478                                 wsi->u.hdr.current_token_limit = sizeof(wsi->u.hdr.ah->data);
 479
 480                         if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 481                                 goto set_parsing_complete;
 482
 483                         goto start_fragment;
 484                 }
 485                 break;
 486
 487 start_fragment:
 488                 wsi->u.hdr.ah->next_frag_index++;
 489                 if (wsi->u.hdr.ah->next_frag_index ==
 490                                 sizeof(wsi->u.hdr.ah->frags) /
 491                                               sizeof(wsi->u.hdr.ah->frags[0])) {
 492                         lwsl_warn("More hdr frags than we can deal with\n");
 493                         return -1;
 494                 }
 495
 496                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].offset =
 497                                                              wsi->u.hdr.ah->pos;
 498                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len = 0;
 499                 wsi->u.hdr.ah->frags[
 500                             wsi->u.hdr.ah->next_frag_index].next_frag_index = 0;
 501
 502                 n = wsi->u.hdr.ah->frag_index[wsi->u.hdr.parser_state];
 503                 if (!n) { /* first fragment */
 504                         wsi->u.hdr.ah->frag_index[wsi->u.hdr.parser_state] =
 505                                                  wsi->u.hdr.ah->next_frag_index;
 506                         break;
 507                 }
 508                 /* continuation */
 509                 while (wsi->u.hdr.ah->frags[n].next_frag_index)
 510                                 n = wsi->u.hdr.ah->frags[n].next_frag_index;
 511                 wsi->u.hdr.ah->frags[n].next_frag_index =
 512                                                  wsi->u.hdr.ah->next_frag_index;
 513
 514                 if (wsi->u.hdr.ah->pos == sizeof(wsi->u.hdr.ah->data)) {
 515                         lwsl_warn("excessive header content\n");
 516                         return -1;
 517                 }
 518
 519                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = ' ';
 520                 wsi->u.hdr.ah->frags[wsi->u.hdr.ah->next_frag_index].len++;
 521                 break;
 522
 523                 /* skipping arg part of a name we didn't recognize */
 524         case WSI_TOKEN_SKIPPING:
 525                 lwsl_parser("WSI_TOKEN_SKIPPING '%c'\n", c);
 526
 527                 if (c == '\x0d')
 528                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 529                 break;
 530
 531         case WSI_TOKEN_SKIPPING_SAW_CR:
 532                 lwsl_parser("WSI_TOKEN_SKIPPING_SAW_CR '%c'\n", c);
 533                 if (c == '\x0a') {
 534                         wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 535                         wsi->u.hdr.lextable_pos = 0;
 536                 } else
 537                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 538                 break;
 539                 /* we're done, ignore anything else */
 540
 541         case WSI_PARSING_COMPLETE:
 542                 lwsl_parser("WSI_PARSING_COMPLETE '%c'\n", c);
 543                 break;
 544         }
 545
 546         return 0;
 547
 548 set_parsing_complete:
 549
 550         if (lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE)) {
 551                 if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION))
 552                         wsi->ietf_spec_revision =
 553                                atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION));
 554
 555                 lwsl_parser("v%02d hdrs completed\n", wsi->ietf_spec_revision);
 556         }
 557         wsi->u.hdr.parser_state = WSI_PARSING_COMPLETE;
 558         wsi->hdr_parsing_completed = 1;
 559
 560         return 0;
 561 }
 562
 563
 564 /**
 565  * lws_frame_is_binary: true if the current frame was sent in binary mode
 566  *
 567  * @wsi: the connection we are inquiring about
 568  *
 569  * This is intended to be called from the LWS_CALLBACK_RECEIVE callback if
 570  * it's interested to see if the frame it's dealing with was sent in binary
 571  * mode.
 572  */
 573
 574 LWS_VISIBLE int lws_frame_is_binary(struct lws *wsi)
 575 {
 576         return wsi->u.ws.frame_is_binary;
 577 }
 578
 579 int
 580 lws_rx_sm(struct lws *wsi, unsigned char c)
 581 {
 582         struct lws_tokens eff_buf;
 583         int ret = 0;
 584         int callback_action = LWS_CALLBACK_RECEIVE;
 585
 586         switch (wsi->lws_rx_parse_state) {
 587         case LWS_RXPS_NEW:
 588
 589                 switch (wsi->ietf_spec_revision) {
 590                 case 13:
 591                         /*
 592                          * no prepended frame key any more
 593                          */
 594                         wsi->u.ws.all_zero_nonce = 1;
 595                         goto handle_first;
 596
 597                 default:
 598                         lwsl_warn("lws_rx_sm: unknown spec version %d\n",
 599                                                        wsi->ietf_spec_revision);
 600                         break;
 601                 }
 602                 break;
 603         case LWS_RXPS_04_MASK_NONCE_1:
 604                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 605                 if (c)
 606                         wsi->u.ws.all_zero_nonce = 0;
 607                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_2;
 608                 break;
 609         case LWS_RXPS_04_MASK_NONCE_2:
 610                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 611                 if (c)
 612                         wsi->u.ws.all_zero_nonce = 0;
 613                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_3;
 614                 break;
 615         case LWS_RXPS_04_MASK_NONCE_3:
 616                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 617                 if (c)
 618                         wsi->u.ws.all_zero_nonce = 0;
 619
 620                 /*
 621                  * start from the zero'th byte in the XOR key buffer since
 622                  * this is the start of a frame with a new key
 623                  */
 624
 625                 wsi->u.ws.frame_mask_index = 0;
 626
 627                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
 628                 break;
 629
 630         /*
 631          *  04 logical framing from the spec (all this is masked when incoming
 632          *  and has to be unmasked)
 633          *
 634          * We ignore the possibility of extension data because we don't
 635          * negotiate any extensions at the moment.
 636          *
 637          *    0                   1                   2                   3
 638          *    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
 639          *   +-+-+-+-+-------+-+-------------+-------------------------------+
 640          *   |F|R|R|R| opcode|R| Payload len |    Extended payload length    |
 641          *   |I|S|S|S|  (4)  |S|     (7)     |             (16/63)           |
 642          *   |N|V|V|V|       |V|             |   (if payload len==126/127)   |
 643          *   | |1|2|3|       |4|             |                               |
 644          *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 645          *   |     Extended payload length continued, if payload len == 127  |
 646          *   + - - - - - - - - - - - - - - - +-------------------------------+
 647          *   |                               |         Extension data        |
 648          *   +-------------------------------+ - - - - - - - - - - - - - - - +
 649          *   :                                                               :
 650          *   +---------------------------------------------------------------+
 651          *   :                       Application data                        :
 652          *   +---------------------------------------------------------------+
 653          *
 654          *  We pass payload through to userland as soon as we get it, ignoring
 655          *  FIN.  It's up to userland to buffer it up if it wants to see a
 656          *  whole unfragmented block of the original size (which may be up to
 657          *  2^63 long!)
 658          */
 659
 660         case LWS_RXPS_04_FRAME_HDR_1:
 661 handle_first:
 662
 663                 wsi->u.ws.opcode = c & 0xf;
 664                 wsi->u.ws.rsv = c & 0x70;
 665                 wsi->u.ws.final = !!((c >> 7) & 1);
 666
 667                 switch (wsi->u.ws.opcode) {
 668                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 669                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 670                         wsi->u.ws.frame_is_binary =
 671                              wsi->u.ws.opcode == LWS_WS_OPCODE_07__BINARY_FRAME;
 672                         break;
 673                 }
 674                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN;
 675                 break;
 676
 677         case LWS_RXPS_04_FRAME_HDR_LEN:
 678
 679                 wsi->u.ws.this_frame_masked = !!(c & 0x80);
 680
 681                 switch (c & 0x7f) {
 682                 case 126:
 683                         /* control frames are not allowed to have big lengths */
 684                         if (wsi->u.ws.opcode & 8)
 685                                 goto illegal_ctl_length;
 686
 687                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2;
 688                         break;
 689                 case 127:
 690                         /* control frames are not allowed to have big lengths */
 691                         if (wsi->u.ws.opcode & 8)
 692                                 goto illegal_ctl_length;
 693
 694                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8;
 695                         break;
 696                 default:
 697                         wsi->u.ws.rx_packet_length = c & 0x7f;
 698                         if (wsi->u.ws.this_frame_masked)
 699                                 wsi->lws_rx_parse_state =
 700                                                 LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 701                         else
 702                                 if (wsi->u.ws.rx_packet_length)
 703                                         wsi->lws_rx_parse_state =
 704                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 705                                 else {
 706                                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 707                                         goto spill;
 708                                 }
 709                         break;
 710                 }
 711                 break;
 712
 713         case LWS_RXPS_04_FRAME_HDR_LEN16_2:
 714                 wsi->u.ws.rx_packet_length = c << 8;
 715                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1;
 716                 break;
 717
 718         case LWS_RXPS_04_FRAME_HDR_LEN16_1:
 719                 wsi->u.ws.rx_packet_length |= c;
 720                 if (wsi->u.ws.this_frame_masked)
 721                         wsi->lws_rx_parse_state =
 722                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 723                 else
 724                         wsi->lws_rx_parse_state =
 725                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 726                 break;
 727
 728         case LWS_RXPS_04_FRAME_HDR_LEN64_8:
 729                 if (c & 0x80) {
 730                         lwsl_warn("b63 of length must be zero\n");
 731                         /* kill the connection */
 732                         return -1;
 733                 }
 734 #if defined __LP64__
 735                 wsi->u.ws.rx_packet_length = ((size_t)c) << 56;
 736 #else
 737                 wsi->u.ws.rx_packet_length = 0;
 738 #endif
 739                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7;
 740                 break;
 741
 742         case LWS_RXPS_04_FRAME_HDR_LEN64_7:
 743 #if defined __LP64__
 744                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 48;
 745 #endif
 746                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6;
 747                 break;
 748
 749         case LWS_RXPS_04_FRAME_HDR_LEN64_6:
 750 #if defined __LP64__
 751                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 40;
 752 #endif
 753                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5;
 754                 break;
 755
 756         case LWS_RXPS_04_FRAME_HDR_LEN64_5:
 757 #if defined __LP64__
 758                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 32;
 759 #endif
 760                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4;
 761                 break;
 762
 763         case LWS_RXPS_04_FRAME_HDR_LEN64_4:
 764                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 24;
 765                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3;
 766                 break;
 767
 768         case LWS_RXPS_04_FRAME_HDR_LEN64_3:
 769                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 16;
 770                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2;
 771                 break;
 772
 773         case LWS_RXPS_04_FRAME_HDR_LEN64_2:
 774                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 8;
 775                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1;
 776                 break;
 777
 778         case LWS_RXPS_04_FRAME_HDR_LEN64_1:
 779                 wsi->u.ws.rx_packet_length |= ((size_t)c);
 780                 if (wsi->u.ws.this_frame_masked)
 781                         wsi->lws_rx_parse_state =
 782                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 783                 else
 784                         wsi->lws_rx_parse_state =
 785                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 786                 break;
 787
 788         case LWS_RXPS_07_COLLECT_FRAME_KEY_1:
 789                 wsi->u.ws.frame_masking_nonce_04[0] = c;
 790                 if (c)
 791                         wsi->u.ws.all_zero_nonce = 0;
 792                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2;
 793                 break;
 794
 795         case LWS_RXPS_07_COLLECT_FRAME_KEY_2:
 796                 wsi->u.ws.frame_masking_nonce_04[1] = c;
 797                 if (c)
 798                         wsi->u.ws.all_zero_nonce = 0;
 799                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3;
 800                 break;
 801
 802         case LWS_RXPS_07_COLLECT_FRAME_KEY_3:
 803                 wsi->u.ws.frame_masking_nonce_04[2] = c;
 804                 if (c)
 805                         wsi->u.ws.all_zero_nonce = 0;
 806                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4;
 807                 break;
 808
 809         case LWS_RXPS_07_COLLECT_FRAME_KEY_4:
 810                 wsi->u.ws.frame_masking_nonce_04[3] = c;
 811                 if (c)
 812                         wsi->u.ws.all_zero_nonce = 0;
 813                 wsi->lws_rx_parse_state =
 814                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 815                 wsi->u.ws.frame_mask_index = 0;
 816                 if (wsi->u.ws.rx_packet_length == 0) {
 817                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 818                         goto spill;
 819                 }
 820                 break;
 821
 822
 823         case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
 824
 825                 if (!wsi->u.ws.rx_user_buffer) {
 826                         lwsl_err("NULL user buffer...\n");
 827                         return 1;
 828                 }
 829
 830                 if (wsi->u.ws.all_zero_nonce)
 831                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 832                                (wsi->u.ws.rx_user_buffer_head++)] = c;
 833                 else
 834                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 835                                (wsi->u.ws.rx_user_buffer_head++)] =
 836                                    c ^ wsi->u.ws.frame_masking_nonce_04[
 837                                             (wsi->u.ws.frame_mask_index++) & 3];
 838
 839                 if (--wsi->u.ws.rx_packet_length == 0) {
 840                         /* spill because we have the whole frame */
 841                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 842                         goto spill;
 843                 }
 844
 845                 /*
 846                  * if there's no protocol max frame size given, we are
 847                  * supposed to default to LWS_MAX_SOCKET_IO_BUF
 848                  */
 849
 850                 if (!wsi->protocol->rx_buffer_size &&
 851                                         wsi->u.ws.rx_user_buffer_head !=
 852                                                           LWS_MAX_SOCKET_IO_BUF)
 853                         break;
 854                 else
 855                         if (wsi->protocol->rx_buffer_size &&
 856                                         wsi->u.ws.rx_user_buffer_head !=
 857                                                   wsi->protocol->rx_buffer_size)
 858                         break;
 859
 860                 /* spill because we filled our rx buffer */
 861 spill:
 862                 /*
 863                  * is this frame a control packet we should take care of at this
 864                  * layer?  If so service it and hide it from the user callback
 865                  */
 866
 867                 lwsl_parser("spill on %s\n", wsi->protocol->name);
 868
 869                 switch (wsi->u.ws.opcode) {
 870                 case LWS_WS_OPCODE_07__CLOSE:
 871                         /* is this an acknowledgement of our close? */
 872                         if (wsi->state == WSI_STATE_AWAITING_CLOSE_ACK) {
 873                                 /*
 874                                  * fine he has told us he is closing too, let's
 875                                  * finish our close
 876                                  */
 877                                 lwsl_parser("seen client close ack\n");
 878                                 return -1;
 879                         }
 880                         if (wsi->state == WSI_STATE_RETURNED_CLOSE_ALREADY)
 881                                 /* if he sends us 2 CLOSE, kill him */
 882                                 return -1;
 883
 884                         lwsl_parser("server sees client close packet\n");
 885                         wsi->state = WSI_STATE_RETURNED_CLOSE_ALREADY;
 886                         /* deal with the close packet contents as a PONG */
 887                         wsi->u.ws.payload_is_close = 1;
 888                         goto process_as_ping;
 889
 890                 case LWS_WS_OPCODE_07__PING:
 891                         lwsl_info("received %d byte ping, sending pong\n",
 892                                                  wsi->u.ws.rx_user_buffer_head);
 893
 894                         if (wsi->u.ws.ping_pending_flag) {
 895                                 /*
 896                                  * there is already a pending ping payload
 897                                  * we should just log and drop
 898                                  */
 899                                 lwsl_parser("DROP PING since one pending\n");
 900                                 goto ping_drop;
 901                         }
 902 process_as_ping:
 903                         /* control packets can only be < 128 bytes long */
 904                         if (wsi->u.ws.rx_user_buffer_head > 128 - 4) {
 905                                 lwsl_parser("DROP PING payload too large\n");
 906                                 goto ping_drop;
 907                         }
 908
 909                         /* if existing buffer is too small, drop it */
 910                         if (wsi->u.ws.ping_payload_buf &&
 911                             wsi->u.ws.ping_payload_alloc < wsi->u.ws.rx_user_buffer_head) {
 912                                 lws_free2(wsi->u.ws.ping_payload_buf);
 913                         }
 914
 915                         /* if no buffer, allocate it */
 916                         if (!wsi->u.ws.ping_payload_buf) {
 917                                 wsi->u.ws.ping_payload_buf = lws_malloc(wsi->u.ws.rx_user_buffer_head
 918                                                                         + LWS_SEND_BUFFER_PRE_PADDING);
 919                                 wsi->u.ws.ping_payload_alloc = wsi->u.ws.rx_user_buffer_head;
 920                         }
 921
 922                         /* stash the pong payload */
 923                         memcpy(wsi->u.ws.ping_payload_buf + LWS_SEND_BUFFER_PRE_PADDING,
 924                                &wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
 925                                 wsi->u.ws.rx_user_buffer_head);
 926
 927                         wsi->u.ws.ping_payload_len = wsi->u.ws.rx_user_buffer_head;
 928                         wsi->u.ws.ping_pending_flag = 1;
 929
 930                         /* get it sent as soon as possible */
 931                         lws_callback_on_writable(lws_get_ctx(wsi), wsi);
 932 ping_drop:
 933                         wsi->u.ws.rx_user_buffer_head = 0;
 934                         return 0;
 935
 936                 case LWS_WS_OPCODE_07__PONG:
 937                         lwsl_info("received pong\n");
 938                         lwsl_hexdump(&wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
 939                                      wsi->u.ws.rx_user_buffer_head);
 940
 941                         /* issue it */
 942                         callback_action = LWS_CALLBACK_RECEIVE_PONG;
 943                         break;
 944
 945                 case LWS_WS_OPCODE_07__TEXT_FRAME:
 946                 case LWS_WS_OPCODE_07__BINARY_FRAME:
 947                 case LWS_WS_OPCODE_07__CONTINUATION:
 948                         break;
 949
 950                 default:
 951                         lwsl_parser("passing opc %x up to exts\n",
 952                                                         wsi->u.ws.opcode);
 953                         /*
 954                          * It's something special we can't understand here.
 955                          * Pass the payload up to the extension's parsing
 956                          * state machine.
 957                          */
 958
 959                         eff_buf.token = &wsi->u.ws.rx_user_buffer[
 960                                                    LWS_SEND_BUFFER_PRE_PADDING];
 961                         eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 962
 963                         if (lws_ext_callback_for_each_active(wsi,
 964                                 LWS_EXT_CALLBACK_EXTENDED_PAYLOAD_RX,
 965                                         &eff_buf, 0) <= 0) /* not handle or fail */
 966                                 lwsl_ext("ext opc opcode 0x%x unknown\n",
 967                                                               wsi->u.ws.opcode);
 968
 969                         wsi->u.ws.rx_user_buffer_head = 0;
 970                         return 0;
 971                 }
 972
 973                 /*
 974                  * No it's real payload, pass it up to the user callback.
 975                  * It's nicely buffered with the pre-padding taken care of
 976                  * so it can be sent straight out again using lws_write
 977                  */
 978
 979                 eff_buf.token = &wsi->u.ws.rx_user_buffer[
 980                                                 LWS_SEND_BUFFER_PRE_PADDING];
 981                 eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
 982
 983                 if (lws_ext_callback_for_each_active(wsi,
 984                                 LWS_EXT_CALLBACK_PAYLOAD_RX, &eff_buf, 0) < 0)
 985                         return -1;
 986
 987                 if (eff_buf.token_len > 0 ||
 988                     callback_action == LWS_CALLBACK_RECEIVE_PONG) {
 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                                                 lws_get_ctx(wsi),
 999                                                 wsi,
1000                                                 (enum lws_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  * lws_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 lws_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 lws_remaining_packet_payload(struct lws *wsi)
1042 {
1043         return wsi->u.ws.rx_packet_length;
1044 }