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 LWS_WARN_UNUSED_RESULT
  31 lextable_decode(int pos, char c)
  32 {
  33         if (c >= 'A' && c <= 'Z')
  34                 c += 'a' - 'A';
  35
  36         while (1) {
  37                 if (lextable[pos] & (1 << 7)) { /* 1-byte, fail on mismatch */
  38                         if ((lextable[pos] & 0x7f) != c)
  39                                 return -1;
  40                         /* fall thru */
  41                         pos++;
  42                         if (lextable[pos] == FAIL_CHAR)
  43                                 return -1;
  44                         return pos;
  45                 }
  46
  47                 if (lextable[pos] == FAIL_CHAR)
  48                         return -1;
  49
  50                 /* b7 = 0, end or 3-byte */
  51                 if (lextable[pos] < FAIL_CHAR) /* terminal marker */
  52                         return pos;
  53
  54                 if (lextable[pos] == c) /* goto */
  55                         return pos + (lextable[pos + 1]) +
  56                                                 (lextable[pos + 2] << 8);
  57                 /* fall thru goto */
  58                 pos += 3;
  59                 /* continue */
  60         }
  61 }
  62
  63 void
  64 lws_header_table_reset(struct lws *wsi)
  65 {
  66         struct allocated_headers *ah = wsi->u.hdr.ah;
  67
  68         /* if we have the idea we're resetting 'our' ah, must be bound to one */
  69         assert(ah);
  70         /* ah also concurs with ownership */
  71         assert(ah->wsi == wsi);
  72
  73         /* init the ah to reflect no headers or data have appeared yet */
  74         memset(ah->frag_index, 0, sizeof(ah->frag_index));
  75         ah->nfrag = 0;
  76         ah->pos = 0;
  77
  78         /* and reset the rx state */
  79         ah->rxpos = 0;
  80         ah->rxlen = 0;
  81
  82         /* since we will restart the ah, our new headers are not completed */
  83         wsi->hdr_parsing_completed = 0;
  84
  85         /*
  86          * if we inherited pending rx (from socket adoption deferred
  87          * processing), apply and free it.
  88          */
  89         if (wsi->u.hdr.preamble_rx) {
  90                 memcpy(ah->rx, wsi->u.hdr.preamble_rx, wsi->u.hdr.preamble_rx_len);
  91                 ah->rxlen = wsi->u.hdr.preamble_rx_len;
  92                 lws_free_set_NULL(wsi->u.hdr.preamble_rx);
  93         }
  94 }
  95
  96 int LWS_WARN_UNUSED_RESULT
  97 lws_header_table_attach(struct lws *wsi)
  98 {
  99         struct lws_context *context = wsi->context;
 100         struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
 101         struct lws_pollargs pa;
 102         struct lws **pwsi;
 103         int n;
 104
 105         lwsl_info("%s: wsi %p: ah %p (tsi %d)\n", __func__, (void *)wsi,
 106                  (void *)wsi->u.hdr.ah, wsi->tsi);
 107
 108         /* if we are already bound to one, just clear it down */
 109         if (wsi->u.hdr.ah) {
 110                 lwsl_info("cleardown\n");
 111                 goto reset;
 112         }
 113
 114         lws_pt_lock(pt);
 115         pwsi = &pt->ah_wait_list;
 116         while (*pwsi) {
 117                 if (*pwsi == wsi) {
 118                         /* if already waiting on list, if no new ah just ret */
 119                         if (pt->ah_count_in_use ==
 120                             context->max_http_header_pool) {
 121                                 lwsl_err("ah wl denied\n");
 122                                 goto bail;
 123                         }
 124                         /* new ah.... remove ourselves from waiting list */
 125                         *pwsi = wsi->u.hdr.ah_wait_list; /* set our prev to our next */
 126                         wsi->u.hdr.ah_wait_list = NULL; /* no next any more */
 127                         pt->ah_wait_list_length--;
 128                         break;
 129                 }
 130                 pwsi = &(*pwsi)->u.hdr.ah_wait_list;
 131         }
 132         /*
 133          * pool is all busy... add us to waiting list and return that we
 134          * weren't able to deliver it right now
 135          */
 136         if (pt->ah_count_in_use == context->max_http_header_pool) {
 137                 lwsl_info("%s: adding %p to ah waiting list\n", __func__, wsi);
 138                 wsi->u.hdr.ah_wait_list = pt->ah_wait_list;
 139                 pt->ah_wait_list = wsi;
 140                 pt->ah_wait_list_length++;
 141
 142                 /* we cannot accept input then */
 143
 144                 _lws_change_pollfd(wsi, LWS_POLLIN, 0, &pa);
 145                 goto bail;
 146         }
 147
 148         for (n = 0; n < context->max_http_header_pool; n++)
 149                 if (!pt->ah_pool[n].in_use)
 150                         break;
 151
 152         /* if the count of in use said something free... */
 153         assert(n != context->max_http_header_pool);
 154
 155         wsi->u.hdr.ah = &pt->ah_pool[n];
 156         wsi->u.hdr.ah->in_use = 1;
 157         pt->ah_pool[n].wsi = wsi; /* mark our owner */
 158         pt->ah_count_in_use++;
 159
 160         _lws_change_pollfd(wsi, 0, LWS_POLLIN, &pa);
 161
 162         lwsl_info("%s: wsi %p: ah %p: count %d (on exit)\n", __func__,
 163                   (void *)wsi, (void *)wsi->u.hdr.ah, pt->ah_count_in_use);
 164
 165         lws_pt_unlock(pt);
 166
 167 reset:
 168         lws_header_table_reset(wsi);
 169         time(&wsi->u.hdr.ah->assigned);
 170
 171         return 0;
 172
 173 bail:
 174         lws_pt_unlock(pt);
 175
 176         return 1;
 177 }
 178
 179 int lws_header_table_detach(struct lws *wsi)
 180 {
 181         struct lws_context *context = wsi->context;
 182         struct allocated_headers *ah = wsi->u.hdr.ah;
 183         struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
 184         struct lws_pollargs pa;
 185         struct lws **pwsi;
 186         time_t now;
 187
 188         lwsl_info("%s: wsi %p: ah %p (tsi=%d, count = %d)\n", __func__,
 189                   (void *)wsi, (void *)wsi->u.hdr.ah, wsi->tsi,
 190                   pt->ah_count_in_use);
 191
 192         if (wsi->u.hdr.preamble_rx)
 193                 lws_free_set_NULL(wsi->u.hdr.preamble_rx);
 194
 195         /* may not be detached while he still has unprocessed rx */
 196         if (ah && ah->rxpos != ah->rxlen) {
 197                 lwsl_err("%s: %p: rxpos:%d, rxlen:%d\n", __func__, wsi,
 198                                 ah->rxpos, ah->rxlen);
 199                 assert(ah->rxpos == ah->rxlen);
 200         }
 201
 202         lws_pt_lock(pt);
 203
 204         pwsi = &pt->ah_wait_list;
 205         if (!ah) { /* remove from wait list if none attached */
 206                 while (*pwsi) {
 207                         if (*pwsi == wsi) {
 208                                 lwsl_info("%s: wsi %p, remv wait\n",
 209                                           __func__, wsi);
 210                                 *pwsi = wsi->u.hdr.ah_wait_list;
 211                                 wsi->u.hdr.ah_wait_list = NULL;
 212                                 pt->ah_wait_list_length--;
 213                                 goto bail;
 214                         }
 215                         pwsi = &(*pwsi)->u.hdr.ah_wait_list;
 216                 }
 217                 /* no ah, not on list... no more business here */
 218                 goto bail;
 219         }
 220         /* we did have an ah attached */
 221         time(&now);
 222         if (now - wsi->u.hdr.ah->assigned > 3) {
 223                 /*
 224                  * we're detaching the ah, but it was held an
 225                  * unreasonably long time
 226                  */
 227                 lwsl_notice("%s: wsi %p: ah held %ds, "
 228                             "ah.rxpos %d, ah.rxlen %d, mode/state %d %d,"
 229                             "wsi->more_rx_waiting %d\n", __func__, wsi,
 230                             (int)(now - wsi->u.hdr.ah->assigned),
 231                             ah->rxpos, ah->rxlen, wsi->mode, wsi->state,
 232                             wsi->u.hdr.more_rx_waiting);
 233         }
 234
 235         /* if we think we're detaching one, there should be one in use */
 236         assert(pt->ah_count_in_use > 0);
 237         /* and this specific one should have been in use */
 238         assert(wsi->u.hdr.ah->in_use);
 239         wsi->u.hdr.ah = NULL;
 240         ah->wsi = NULL; /* no owner */
 241
 242         /* oh there is nobody on the waiting list... leave it at that then */
 243         if (!*pwsi) {
 244                 ah->in_use = 0;
 245                 pt->ah_count_in_use--;
 246
 247                 goto bail;
 248         }
 249
 250         /* somebody else on same tsi is waiting, give it to oldest guy */
 251
 252         lwsl_info("pt wait list %p\n", *pwsi);
 253         while ((*pwsi)->u.hdr.ah_wait_list)
 254                 pwsi = &(*pwsi)->u.hdr.ah_wait_list;
 255
 256         wsi = *pwsi;
 257         lwsl_info("last wsi in wait list %p\n", wsi);
 258
 259         wsi->u.hdr.ah = ah;
 260         ah->wsi = wsi; /* new owner */
 261         lws_header_table_reset(wsi);
 262         time(&wsi->u.hdr.ah->assigned);
 263
 264         assert(wsi->position_in_fds_table != -1);
 265
 266         lwsl_info("%s: Enabling %p POLLIN\n", __func__, wsi);
 267
 268         /* he has been stuck waiting for an ah, but now his wait is over,
 269          * let him progress
 270          */
 271         _lws_change_pollfd(wsi, 0, LWS_POLLIN, &pa);
 272
 273         /* point prev guy to next guy in list instead */
 274         *pwsi = wsi->u.hdr.ah_wait_list;
 275         /* the guy who got one is out of the list */
 276         wsi->u.hdr.ah_wait_list = NULL;
 277         pt->ah_wait_list_length--;
 278
 279         assert(!!pt->ah_wait_list_length == !!(int)(long)pt->ah_wait_list);
 280 bail:
 281         lws_pt_unlock(pt);
 282
 283         return 0;
 284 }
 285
 286 /**
 287  * lws_hdr_fragment_length: report length of a single fragment of a header
 288  *              The returned length does not include the space for a
 289  *              terminating '\0'
 290  *
 291  * @wsi: websocket connection
 292  * @h: which header index we are interested in
 293  * @frag_idx: which fragment of @h we want to get the length of
 294  */
 295
 296 LWS_VISIBLE int
 297 lws_hdr_fragment_length(struct lws *wsi, enum lws_token_indexes h, int frag_idx)
 298 {
 299         int n;
 300
 301         n = wsi->u.hdr.ah->frag_index[h];
 302         if (!n)
 303                 return 0;
 304         do {
 305                 if (!frag_idx)
 306                         return wsi->u.hdr.ah->frags[n].len;
 307                 n = wsi->u.hdr.ah->frags[n].nfrag;
 308         } while (frag_idx-- && n);
 309
 310         return 0;
 311 }
 312
 313 /**
 314  * lws_hdr_total_length: report length of all fragments of a header totalled up
 315  *              The returned length does not include the space for a
 316  *              terminating '\0'
 317  *
 318  * @wsi: websocket connection
 319  * @h: which header index we are interested in
 320  */
 321
 322 LWS_VISIBLE int lws_hdr_total_length(struct lws *wsi, enum lws_token_indexes h)
 323 {
 324         int n;
 325         int len = 0;
 326
 327         n = wsi->u.hdr.ah->frag_index[h];
 328         if (!n)
 329                 return 0;
 330         do {
 331                 len += wsi->u.hdr.ah->frags[n].len;
 332                 n = wsi->u.hdr.ah->frags[n].nfrag;
 333         } while (n);
 334
 335         return len;
 336 }
 337
 338 /**
 339  * lws_hdr_copy_fragment: copy a single fragment of the given header to a buffer
 340  *              The buffer length @len must include space for an additional
 341  *              terminating '\0', or it will fail returning -1.
 342  *              If the requested fragment index is not present, it fails
 343  *              returning -1.
 344  *
 345  * @wsi: websocket connection
 346  * @dst: destination buffer
 347  * @len: length of destination buffer
 348  * @h: which header index we are interested in
 349  * @frag_index: which fragment of @h we want to copy
 350  */
 351
 352 LWS_VISIBLE int lws_hdr_copy_fragment(struct lws *wsi, char *dst, int len,
 353                                       enum lws_token_indexes h, int frag_idx)
 354 {
 355         int n = 0;
 356         int f = wsi->u.hdr.ah->frag_index[h];
 357
 358         if (!f)
 359                 return -1;
 360
 361         while (n < frag_idx) {
 362                 f = wsi->u.hdr.ah->frags[f].nfrag;
 363                 if (!f)
 364                         return -1;
 365                 n++;
 366         }
 367
 368         if (wsi->u.hdr.ah->frags[f].len >= len)
 369                 return -1;
 370
 371         memcpy(dst, wsi->u.hdr.ah->data + wsi->u.hdr.ah->frags[f].offset,
 372                wsi->u.hdr.ah->frags[f].len);
 373         dst[wsi->u.hdr.ah->frags[f].len] = '\0';
 374
 375         return wsi->u.hdr.ah->frags[f].len;
 376 }
 377
 378 /**
 379  * lws_hdr_copy: copy a single fragment of the given header to a buffer
 380  *              The buffer length @len must include space for an additional
 381  *              terminating '\0', or it will fail returning -1.
 382  *
 383  * @wsi: websocket connection
 384  * @dst: destination buffer
 385  * @len: length of destination buffer
 386  * @h: which header index we are interested in
 387  */
 388
 389 LWS_VISIBLE int lws_hdr_copy(struct lws *wsi, char *dst, int len,
 390                              enum lws_token_indexes h)
 391 {
 392         int toklen = lws_hdr_total_length(wsi, h);
 393         int n;
 394
 395         if (toklen >= len)
 396                 return -1;
 397
 398         n = wsi->u.hdr.ah->frag_index[h];
 399         if (!n)
 400                 return 0;
 401
 402         do {
 403                 strcpy(dst, &wsi->u.hdr.ah->data[wsi->u.hdr.ah->frags[n].offset]);
 404                 dst += wsi->u.hdr.ah->frags[n].len;
 405                 n = wsi->u.hdr.ah->frags[n].nfrag;
 406         } while (n);
 407
 408         return toklen;
 409 }
 410
 411 char *lws_hdr_simple_ptr(struct lws *wsi, enum lws_token_indexes h)
 412 {
 413         int n;
 414
 415         n = wsi->u.hdr.ah->frag_index[h];
 416         if (!n)
 417                 return NULL;
 418
 419         return wsi->u.hdr.ah->data + wsi->u.hdr.ah->frags[n].offset;
 420 }
 421
 422 int LWS_WARN_UNUSED_RESULT
 423 lws_pos_in_bounds(struct lws *wsi)
 424 {
 425         if (wsi->u.hdr.ah->pos < wsi->context->max_http_header_data)
 426                 return 0;
 427
 428         if (wsi->u.hdr.ah->pos == wsi->context->max_http_header_data) {
 429                 lwsl_err("Ran out of header data space\n");
 430                 return 1;
 431         }
 432
 433         /*
 434          * with these tests everywhere, it should never be able to exceed
 435          * the limit, only meet the limit
 436          */
 437
 438         lwsl_err("%s: pos %d, limit %d\n", __func__, wsi->u.hdr.ah->pos,
 439                  wsi->context->max_http_header_data);
 440         assert(0);
 441
 442         return 1;
 443 }
 444
 445 int LWS_WARN_UNUSED_RESULT
 446 lws_hdr_simple_create(struct lws *wsi, enum lws_token_indexes h, const char *s)
 447 {
 448         wsi->u.hdr.ah->nfrag++;
 449         if (wsi->u.hdr.ah->nfrag == ARRAY_SIZE(wsi->u.hdr.ah->frags)) {
 450                 lwsl_warn("More hdr frags than we can deal with, dropping\n");
 451                 return -1;
 452         }
 453
 454         wsi->u.hdr.ah->frag_index[h] = wsi->u.hdr.ah->nfrag;
 455
 456         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].offset = wsi->u.hdr.ah->pos;
 457         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len = 0;
 458         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].nfrag = 0;
 459
 460         do {
 461                 if (lws_pos_in_bounds(wsi))
 462                         return -1;
 463
 464                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = *s;
 465                 if (*s)
 466                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len++;
 467         } while (*s++);
 468
 469         return 0;
 470 }
 471
 472 static signed char char_to_hex(const char c)
 473 {
 474         if (c >= '0' && c <= '9')
 475                 return c - '0';
 476
 477         if (c >= 'a' && c <= 'f')
 478                 return c - 'a' + 10;
 479
 480         if (c >= 'A' && c <= 'F')
 481                 return c - 'A' + 10;
 482
 483         return -1;
 484 }
 485
 486 static int LWS_WARN_UNUSED_RESULT
 487 issue_char(struct lws *wsi, unsigned char c)
 488 {
 489         unsigned short frag_len;
 490
 491         if (lws_pos_in_bounds(wsi))
 492                 return -1;
 493
 494         frag_len = wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len;
 495         /*
 496          * If we haven't hit the token limit, just copy the character into
 497          * the header
 498          */
 499         if (frag_len < wsi->u.hdr.current_token_limit) {
 500                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = c;
 501                 if (c)
 502                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len++;
 503                 return 0;
 504         }
 505
 506         /* Insert a null character when we *hit* the limit: */
 507         if (frag_len == wsi->u.hdr.current_token_limit) {
 508                 if (lws_pos_in_bounds(wsi))
 509                         return -1;
 510                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 511                 lwsl_warn("header %i exceeds limit %d\n",
 512                           wsi->u.hdr.parser_state,
 513                           wsi->u.hdr.current_token_limit);
 514         }
 515
 516         return 1;
 517 }
 518
 519 int LWS_WARN_UNUSED_RESULT
 520 lws_parse(struct lws *wsi, unsigned char c)
 521 {
 522         static const unsigned char methods[] = {
 523                 WSI_TOKEN_GET_URI,
 524                 WSI_TOKEN_POST_URI,
 525                 WSI_TOKEN_OPTIONS_URI,
 526                 WSI_TOKEN_PUT_URI,
 527                 WSI_TOKEN_PATCH_URI,
 528                 WSI_TOKEN_DELETE_URI,
 529         };
 530         struct allocated_headers *ah = wsi->u.hdr.ah;
 531         struct lws_context *context = wsi->context;
 532         unsigned int n, m, enc = 0;
 533
 534         assert(wsi->u.hdr.ah);
 535
 536         switch (wsi->u.hdr.parser_state) {
 537         default:
 538
 539                 lwsl_parser("WSI_TOK_(%d) '%c'\n", wsi->u.hdr.parser_state, c);
 540
 541                 /* collect into malloc'd buffers */
 542                 /* optional initial space swallow */
 543                 if (!ah->frags[ah->frag_index[wsi->u.hdr.parser_state]].len &&
 544                     c == ' ')
 545                         break;
 546
 547                 for (m = 0; m < ARRAY_SIZE(methods); m++)
 548                         if (wsi->u.hdr.parser_state == methods[m])
 549                                 break;
 550                 if (m == ARRAY_SIZE(methods))
 551                         /* it was not any of the methods */
 552                         goto check_eol;
 553
 554                 /* special URI processing... end at space */
 555
 556                 if (c == ' ') {
 557                         /* enforce starting with / */
 558                         if (!ah->frags[ah->nfrag].len)
 559                                 if (issue_char(wsi, '/') < 0)
 560                                         return -1;
 561
 562                         /* begin parsing HTTP version: */
 563                         if (issue_char(wsi, '\0') < 0)
 564                                 return -1;
 565                         wsi->u.hdr.parser_state = WSI_TOKEN_HTTP;
 566                         goto start_fragment;
 567                 }
 568
 569                 /* special URI processing... convert %xx */
 570
 571                 switch (wsi->u.hdr.ues) {
 572                 case URIES_IDLE:
 573                         if (c == '%') {
 574                                 wsi->u.hdr.ues = URIES_SEEN_PERCENT;
 575                                 goto swallow;
 576                         }
 577                         break;
 578                 case URIES_SEEN_PERCENT:
 579                         if (char_to_hex(c) < 0) {
 580                                 /* regurgitate */
 581                                 if (issue_char(wsi, '%') < 0)
 582                                         return -1;
 583                                 wsi->u.hdr.ues = URIES_IDLE;
 584                                 /* continue on to assess c */
 585                                 break;
 586                         }
 587                         wsi->u.hdr.esc_stash = c;
 588                         wsi->u.hdr.ues = URIES_SEEN_PERCENT_H1;
 589                         goto swallow;
 590
 591                 case URIES_SEEN_PERCENT_H1:
 592                         if (char_to_hex(c) < 0) {
 593                                 /* regurgitate */
 594                                 if (issue_char(wsi, '%') < 0)
 595                                         return -1;
 596                                 wsi->u.hdr.ues = URIES_IDLE;
 597                                 /* regurgitate + assess */
 598                                 if (lws_parse(wsi, wsi->u.hdr.esc_stash) < 0)
 599                                         return -1;
 600                                 /* continue on to assess c */
 601                                 break;
 602                         }
 603                         c = (char_to_hex(wsi->u.hdr.esc_stash) << 4) |
 604                                         char_to_hex(c);
 605                         enc = 1;
 606                         wsi->u.hdr.ues = URIES_IDLE;
 607                         break;
 608                 }
 609
 610                 /*
 611                  * special URI processing...
 612                  *  convert /.. or /... or /../ etc to /
 613                  *  convert /./ to /
 614                  *  convert // or /// etc to /
 615                  *  leave /.dir or whatever alone
 616                  */
 617
 618                 switch (wsi->u.hdr.ups) {
 619                 case URIPS_IDLE:
 620                         if (!c)
 621                                 return -1;
 622                         /* genuine delimiter */
 623                         if ((c == '&' || c == ';') && !enc) {
 624                                 if (issue_char(wsi, c) < 0)
 625                                         return -1;
 626                                 /* swallow the terminator */
 627                                 ah->frags[ah->nfrag].len--;
 628                                 /* link to next fragment */
 629                                 ah->frags[ah->nfrag].nfrag = ah->nfrag + 1;
 630                                 ah->nfrag++;
 631                                 if (ah->nfrag >= ARRAY_SIZE(ah->frags))
 632                                         goto excessive;
 633                                 /* start next fragment after the & */
 634                                 wsi->u.hdr.post_literal_equal = 0;
 635                                 ah->frags[ah->nfrag].offset = ah->pos;
 636                                 ah->frags[ah->nfrag].len = 0;
 637                                 ah->frags[ah->nfrag].nfrag = 0;
 638                                 goto swallow;
 639                         }
 640                         /* uriencoded = in the name part, disallow */
 641                         if (c == '=' && enc && !wsi->u.hdr.post_literal_equal)
 642                                 c = '_';
 643
 644                         /* after the real =, we don't care how many = */
 645                         if (c == '=' && !enc)
 646                                 wsi->u.hdr.post_literal_equal = 1;
 647
 648                         /* + to space */
 649                         if (c == '+' && !enc)
 650                                 c = ' ';
 651                         /* issue the first / always */
 652                         if (c == '/' && !ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS])
 653                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 654                         break;
 655                 case URIPS_SEEN_SLASH:
 656                         /* swallow subsequent slashes */
 657                         if (c == '/')
 658                                 goto swallow;
 659                         /* track and swallow the first . after / */
 660                         if (c == '.') {
 661                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT;
 662                                 goto swallow;
 663                         }
 664                         wsi->u.hdr.ups = URIPS_IDLE;
 665                         break;
 666                 case URIPS_SEEN_SLASH_DOT:
 667                         /* swallow second . */
 668                         if (c == '.') {
 669                                 /*
 670                                  * back up one dir level if possible
 671                                  * safe against header fragmentation because
 672                                  * the method URI can only be in 1 fragment
 673                                  */
 674                                 if (ah->frags[ah->nfrag].len > 2) {
 675                                         ah->pos--;
 676                                         ah->frags[ah->nfrag].len--;
 677                                         do {
 678                                                 ah->pos--;
 679                                                 ah->frags[ah->nfrag].len--;
 680                                         } while (ah->frags[ah->nfrag].len > 1 &&
 681                                                  ah->data[ah->pos] != '/');
 682                                 }
 683                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT_DOT;
 684                                 goto swallow;
 685                         }
 686                         /* change /./ to / */
 687                         if (c == '/') {
 688                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 689                                 goto swallow;
 690                         }
 691                         /* it was like /.dir ... regurgitate the . */
 692                         wsi->u.hdr.ups = URIPS_IDLE;
 693                         if (issue_char(wsi, '.') < 0)
 694                                 return -1;
 695                         break;
 696
 697                 case URIPS_SEEN_SLASH_DOT_DOT:
 698                         /* swallow prior .. chars and any subsequent . */
 699                         if (c == '.')
 700                                 goto swallow;
 701                         /* last issued was /, so another / == // */
 702                         if (c == '/')
 703                                 goto swallow;
 704                         /* last we issued was / so SEEN_SLASH */
 705                         wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 706                         break;
 707                 }
 708
 709                 if (c == '?' && !enc &&
 710                     !ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS]) { /* start of URI arguments */
 711                         /* seal off uri header */
 712                         if (issue_char(wsi, '\0') < 0)
 713                                 return -1;
 714
 715                         /* move to using WSI_TOKEN_HTTP_URI_ARGS */
 716                         ah->nfrag++;
 717                         if (ah->nfrag >= ARRAY_SIZE(ah->frags))
 718                                 goto excessive;
 719                         ah->frags[ah->nfrag].offset = ah->pos;
 720                         ah->frags[ah->nfrag].len = 0;
 721                         ah->frags[ah->nfrag].nfrag = 0;
 722
 723                         wsi->u.hdr.post_literal_equal = 0;
 724                         ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS] = ah->nfrag;
 725                         wsi->u.hdr.ups = URIPS_IDLE;
 726                         goto swallow;
 727                 }
 728
 729 check_eol:
 730
 731                 /* bail at EOL */
 732                 if (wsi->u.hdr.parser_state != WSI_TOKEN_CHALLENGE &&
 733                     c == '\x0d') {
 734                         c = '\0';
 735                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 736                         lwsl_parser("*\n");
 737                 }
 738
 739                 n = issue_char(wsi, c);
 740                 if ((int)n < 0)
 741                         return -1;
 742                 if (n > 0)
 743                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 744
 745 swallow:
 746                 /* per-protocol end of headers management */
 747
 748                 if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 749                         goto set_parsing_complete;
 750                 break;
 751
 752                 /* collecting and checking a name part */
 753         case WSI_TOKEN_NAME_PART:
 754                 lwsl_parser("WSI_TOKEN_NAME_PART '%c' (mode=%d)\n", c, wsi->mode);
 755
 756                 wsi->u.hdr.lextable_pos =
 757                                 lextable_decode(wsi->u.hdr.lextable_pos, c);
 758                 /*
 759                  * Server needs to look out for unknown methods...
 760                  */
 761                 if (wsi->u.hdr.lextable_pos < 0 &&
 762                     wsi->mode == LWSCM_HTTP_SERVING) {
 763                         /* this is not a header we know about */
 764                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 765                                 if (ah->frag_index[methods[m]]) {
 766                                         /*
 767                                          * already had the method, no idea what
 768                                          * this crap from the client is, ignore
 769                                          */
 770                                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 771                                         break;
 772                                 }
 773                         /*
 774                          * hm it's an unknown http method from a client in fact,
 775                          * treat as dangerous
 776                          */
 777                         if (m == ARRAY_SIZE(methods)) {
 778                                 lwsl_info("Unknown method - dropping\n");
 779                                 return -1;
 780                         }
 781                         break;
 782                 }
 783                 /*
 784                  * ...otherwise for a client, let him ignore unknown headers
 785                  * coming from the server
 786                  */
 787                 if (wsi->u.hdr.lextable_pos < 0) {
 788                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 789                         break;
 790                 }
 791
 792                 if (lextable[wsi->u.hdr.lextable_pos] < FAIL_CHAR) {
 793                         /* terminal state */
 794
 795                         n = ((unsigned int)lextable[wsi->u.hdr.lextable_pos] << 8) |
 796                                         lextable[wsi->u.hdr.lextable_pos + 1];
 797
 798                         lwsl_parser("known hdr %d\n", n);
 799                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 800                                 if (n == methods[m] &&
 801                                     ah->frag_index[methods[m]]) {
 802                                         lwsl_warn("Duplicated method\n");
 803                                         return -1;
 804                                 }
 805
 806                         /*
 807                          * WSORIGIN is protocol equiv to ORIGIN,
 808                          * JWebSocket likes to send it, map to ORIGIN
 809                          */
 810                         if (n == WSI_TOKEN_SWORIGIN)
 811                                 n = WSI_TOKEN_ORIGIN;
 812
 813                         wsi->u.hdr.parser_state = (enum lws_token_indexes)
 814                                                         (WSI_TOKEN_GET_URI + n);
 815
 816                         if (context->token_limits)
 817                                 wsi->u.hdr.current_token_limit =
 818                                         context->token_limits->token_limit[
 819                                                        wsi->u.hdr.parser_state];
 820                         else
 821                                 wsi->u.hdr.current_token_limit =
 822                                         wsi->context->max_http_header_data;
 823
 824                         if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 825                                 goto set_parsing_complete;
 826
 827                         goto start_fragment;
 828                 }
 829                 break;
 830
 831 start_fragment:
 832                 ah->nfrag++;
 833 excessive:
 834                 if (ah->nfrag == ARRAY_SIZE(ah->frags)) {
 835                         lwsl_warn("More hdr frags than we can deal with\n");
 836                         return -1;
 837                 }
 838
 839                 ah->frags[ah->nfrag].offset = ah->pos;
 840                 ah->frags[ah->nfrag].len = 0;
 841                 ah->frags[ah->nfrag].nfrag = 0;
 842
 843                 n = ah->frag_index[wsi->u.hdr.parser_state];
 844                 if (!n) { /* first fragment */
 845                         ah->frag_index[wsi->u.hdr.parser_state] = ah->nfrag;
 846                         break;
 847                 }
 848                 /* continuation */
 849                 while (ah->frags[n].nfrag)
 850                         n = ah->frags[n].nfrag;
 851                 ah->frags[n].nfrag = ah->nfrag;
 852
 853                 if (issue_char(wsi, ' ') < 0)
 854                         return -1;
 855                 break;
 856
 857                 /* skipping arg part of a name we didn't recognize */
 858         case WSI_TOKEN_SKIPPING:
 859                 lwsl_parser("WSI_TOKEN_SKIPPING '%c'\n", c);
 860
 861                 if (c == '\x0d')
 862                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 863                 break;
 864
 865         case WSI_TOKEN_SKIPPING_SAW_CR:
 866                 lwsl_parser("WSI_TOKEN_SKIPPING_SAW_CR '%c'\n", c);
 867                 if (c == '\x0a') {
 868                         wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 869                         wsi->u.hdr.lextable_pos = 0;
 870                 } else
 871                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 872                 break;
 873                 /* we're done, ignore anything else */
 874
 875         case WSI_PARSING_COMPLETE:
 876                 lwsl_parser("WSI_PARSING_COMPLETE '%c'\n", c);
 877                 break;
 878         }
 879
 880         return 0;
 881
 882 set_parsing_complete:
 883
 884         if (lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE)) {
 885                 if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION))
 886                         wsi->ietf_spec_revision =
 887                                atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION));
 888
 889                 lwsl_parser("v%02d hdrs completed\n", wsi->ietf_spec_revision);
 890         }
 891         wsi->u.hdr.parser_state = WSI_PARSING_COMPLETE;
 892         wsi->hdr_parsing_completed = 1;
 893
 894         return 0;
 895 }
 896
 897
 898 /**
 899  * lws_frame_is_binary: true if the current frame was sent in binary mode
 900  *
 901  * @wsi: the connection we are inquiring about
 902  *
 903  * This is intended to be called from the LWS_CALLBACK_RECEIVE callback if
 904  * it's interested to see if the frame it's dealing with was sent in binary
 905  * mode.
 906  */
 907
 908 LWS_VISIBLE int lws_frame_is_binary(struct lws *wsi)
 909 {
 910         return wsi->u.ws.frame_is_binary;
 911 }
 912
 913 int
 914 lws_rx_sm(struct lws *wsi, unsigned char c)
 915 {
 916         struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
 917         int callback_action = LWS_CALLBACK_RECEIVE;
 918         int ret = 0, n, rx_draining_ext = 0;
 919         struct lws_tokens eff_buf;
 920
 921         if (wsi->socket_is_permanently_unusable)
 922                 return -1;
 923
 924         switch (wsi->lws_rx_parse_state) {
 925         case LWS_RXPS_NEW:
 926                 if (wsi->u.ws.rx_draining_ext) {
 927                         struct lws **w = &pt->rx_draining_ext_list;
 928
 929                         eff_buf.token = NULL;
 930                         eff_buf.token_len = 0;
 931                         wsi->u.ws.rx_draining_ext = 0;
 932                         /* remove us from context draining ext list */
 933                         while (*w) {
 934                                 if (*w == wsi) {
 935                                         *w = wsi->u.ws.rx_draining_ext_list;
 936                                         break;
 937                                 }
 938                                 w = &((*w)->u.ws.rx_draining_ext_list);
 939                         }
 940                         wsi->u.ws.rx_draining_ext_list = NULL;
 941                         rx_draining_ext = 1;
 942                         lwsl_err("%s: doing draining flow\n", __func__);
 943
 944                         goto drain_extension;
 945                 }
 946                 switch (wsi->ietf_spec_revision) {
 947                 case 13:
 948                         /*
 949                          * no prepended frame key any more
 950                          */
 951                         wsi->u.ws.all_zero_nonce = 1;
 952                         goto handle_first;
 953
 954                 default:
 955                         lwsl_warn("lws_rx_sm: unknown spec version %d\n",
 956                                                        wsi->ietf_spec_revision);
 957                         break;
 958                 }
 959                 break;
 960         case LWS_RXPS_04_mask_1:
 961                 wsi->u.ws.mask[1] = c;
 962                 if (c)
 963                         wsi->u.ws.all_zero_nonce = 0;
 964                 wsi->lws_rx_parse_state = LWS_RXPS_04_mask_2;
 965                 break;
 966         case LWS_RXPS_04_mask_2:
 967                 wsi->u.ws.mask[2] = c;
 968                 if (c)
 969                         wsi->u.ws.all_zero_nonce = 0;
 970                 wsi->lws_rx_parse_state = LWS_RXPS_04_mask_3;
 971                 break;
 972         case LWS_RXPS_04_mask_3:
 973                 wsi->u.ws.mask[3] = c;
 974                 if (c)
 975                         wsi->u.ws.all_zero_nonce = 0;
 976
 977                 /*
 978                  * start from the zero'th byte in the XOR key buffer since
 979                  * this is the start of a frame with a new key
 980                  */
 981
 982                 wsi->u.ws.mask_idx = 0;
 983
 984                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
 985                 break;
 986
 987         /*
 988          *  04 logical framing from the spec (all this is masked when incoming
 989          *  and has to be unmasked)
 990          *
 991          * We ignore the possibility of extension data because we don't
 992          * negotiate any extensions at the moment.
 993          *
 994          *    0                   1                   2                   3
 995          *    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
 996          *   +-+-+-+-+-------+-+-------------+-------------------------------+
 997          *   |F|R|R|R| opcode|R| Payload len |    Extended payload length    |
 998          *   |I|S|S|S|  (4)  |S|     (7)     |             (16/63)           |
 999          *   |N|V|V|V|       |V|             |   (if payload len==126/127)   |
1000          *   | |1|2|3|       |4|             |                               |
1001          *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
1002          *   |     Extended payload length continued, if payload len == 127  |
1003          *   + - - - - - - - - - - - - - - - +-------------------------------+
1004          *   |                               |         Extension data        |
1005          *   +-------------------------------+ - - - - - - - - - - - - - - - +
1006          *   :                                                               :
1007          *   +---------------------------------------------------------------+
1008          *   :                       Application data                        :
1009          *   +---------------------------------------------------------------+
1010          *
1011          *  We pass payload through to userland as soon as we get it, ignoring
1012          *  FIN.  It's up to userland to buffer it up if it wants to see a
1013          *  whole unfragmented block of the original size (which may be up to
1014          *  2^63 long!)
1015          */
1016
1017         case LWS_RXPS_04_FRAME_HDR_1:
1018 handle_first:
1019
1020                 wsi->u.ws.opcode = c & 0xf;
1021                 wsi->u.ws.rsv = c & 0x70;
1022                 wsi->u.ws.final = !!((c >> 7) & 1);
1023
1024                 switch (wsi->u.ws.opcode) {
1025                 case LWSWSOPC_TEXT_FRAME:
1026                 case LWSWSOPC_BINARY_FRAME:
1027                         wsi->u.ws.rsv_first_msg = (c & 0x70);
1028                         wsi->u.ws.frame_is_binary =
1029                              wsi->u.ws.opcode == LWSWSOPC_BINARY_FRAME;
1030                         break;
1031                 case 3:
1032                 case 4:
1033                 case 5:
1034                 case 6:
1035                 case 7:
1036                 case 0xb:
1037                 case 0xc:
1038                 case 0xd:
1039                 case 0xe:
1040                 case 0xf:
1041                         lwsl_info("illegal opcode\n");
1042                         return -1;
1043                 }
1044                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN;
1045                 break;
1046
1047         case LWS_RXPS_04_FRAME_HDR_LEN:
1048
1049                 wsi->u.ws.this_frame_masked = !!(c & 0x80);
1050
1051                 switch (c & 0x7f) {
1052                 case 126:
1053                         /* control frames are not allowed to have big lengths */
1054                         if (wsi->u.ws.opcode & 8)
1055                                 goto illegal_ctl_length;
1056
1057                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2;
1058                         break;
1059                 case 127:
1060                         /* control frames are not allowed to have big lengths */
1061                         if (wsi->u.ws.opcode & 8)
1062                                 goto illegal_ctl_length;
1063
1064                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8;
1065                         break;
1066                 default:
1067                         wsi->u.ws.rx_packet_length = c & 0x7f;
1068                         if (wsi->u.ws.this_frame_masked)
1069                                 wsi->lws_rx_parse_state =
1070                                                 LWS_RXPS_07_COLLECT_FRAME_KEY_1;
1071                         else
1072                                 if (wsi->u.ws.rx_packet_length)
1073                                         wsi->lws_rx_parse_state =
1074                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
1075                                 else {
1076                                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
1077                                         goto spill;
1078                                 }
1079                         break;
1080                 }
1081                 break;
1082
1083         case LWS_RXPS_04_FRAME_HDR_LEN16_2:
1084                 wsi->u.ws.rx_packet_length = c << 8;
1085                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1;
1086                 break;
1087
1088         case LWS_RXPS_04_FRAME_HDR_LEN16_1:
1089                 wsi->u.ws.rx_packet_length |= c;
1090                 if (wsi->u.ws.this_frame_masked)
1091                         wsi->lws_rx_parse_state =
1092                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
1093                 else
1094                         wsi->lws_rx_parse_state =
1095                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
1096                 break;
1097
1098         case LWS_RXPS_04_FRAME_HDR_LEN64_8:
1099                 if (c & 0x80) {
1100                         lwsl_warn("b63 of length must be zero\n");
1101                         /* kill the connection */
1102                         return -1;
1103                 }
1104 #if defined __LP64__
1105                 wsi->u.ws.rx_packet_length = ((size_t)c) << 56;
1106 #else
1107                 wsi->u.ws.rx_packet_length = 0;
1108 #endif
1109                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7;
1110                 break;
1111
1112         case LWS_RXPS_04_FRAME_HDR_LEN64_7:
1113 #if defined __LP64__
1114                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 48;
1115 #endif
1116                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6;
1117                 break;
1118
1119         case LWS_RXPS_04_FRAME_HDR_LEN64_6:
1120 #if defined __LP64__
1121                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 40;
1122 #endif
1123                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5;
1124                 break;
1125
1126         case LWS_RXPS_04_FRAME_HDR_LEN64_5:
1127 #if defined __LP64__
1128                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 32;
1129 #endif
1130                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4;
1131                 break;
1132
1133         case LWS_RXPS_04_FRAME_HDR_LEN64_4:
1134                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 24;
1135                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3;
1136                 break;
1137
1138         case LWS_RXPS_04_FRAME_HDR_LEN64_3:
1139                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 16;
1140                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2;
1141                 break;
1142
1143         case LWS_RXPS_04_FRAME_HDR_LEN64_2:
1144                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 8;
1145                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1;
1146                 break;
1147
1148         case LWS_RXPS_04_FRAME_HDR_LEN64_1:
1149                 wsi->u.ws.rx_packet_length |= ((size_t)c);
1150                 if (wsi->u.ws.this_frame_masked)
1151                         wsi->lws_rx_parse_state =
1152                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
1153                 else
1154                         wsi->lws_rx_parse_state =
1155                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
1156                 break;
1157
1158         case LWS_RXPS_07_COLLECT_FRAME_KEY_1:
1159                 wsi->u.ws.mask[0] = c;
1160                 if (c)
1161                         wsi->u.ws.all_zero_nonce = 0;
1162                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2;
1163                 break;
1164
1165         case LWS_RXPS_07_COLLECT_FRAME_KEY_2:
1166                 wsi->u.ws.mask[1] = c;
1167                 if (c)
1168                         wsi->u.ws.all_zero_nonce = 0;
1169                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3;
1170                 break;
1171
1172         case LWS_RXPS_07_COLLECT_FRAME_KEY_3:
1173                 wsi->u.ws.mask[2] = c;
1174                 if (c)
1175                         wsi->u.ws.all_zero_nonce = 0;
1176                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4;
1177                 break;
1178
1179         case LWS_RXPS_07_COLLECT_FRAME_KEY_4:
1180                 wsi->u.ws.mask[3] = c;
1181                 if (c)
1182                         wsi->u.ws.all_zero_nonce = 0;
1183                 wsi->lws_rx_parse_state =
1184                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
1185                 wsi->u.ws.mask_idx = 0;
1186                 if (wsi->u.ws.rx_packet_length == 0) {
1187                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
1188                         goto spill;
1189                 }
1190                 break;
1191
1192
1193         case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
1194                 assert(wsi->u.ws.rx_ubuf);
1195
1196                 if (wsi->u.ws.rx_ubuf_head + LWS_PRE >=
1197                     wsi->u.ws.rx_ubuf_alloc) {
1198                         lwsl_err("Attempted overflow \n");
1199                         return -1;
1200                 }
1201                 if (wsi->u.ws.all_zero_nonce)
1202                         wsi->u.ws.rx_ubuf[LWS_PRE +
1203                                          (wsi->u.ws.rx_ubuf_head++)] = c;
1204                 else
1205                         wsi->u.ws.rx_ubuf[LWS_PRE +
1206                                (wsi->u.ws.rx_ubuf_head++)] =
1207                                    c ^ wsi->u.ws.mask[
1208                                             (wsi->u.ws.mask_idx++) & 3];
1209
1210                 if (--wsi->u.ws.rx_packet_length == 0) {
1211                         /* spill because we have the whole frame */
1212                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
1213                         goto spill;
1214                 }
1215
1216                 /*
1217                  * if there's no protocol max frame size given, we are
1218                  * supposed to default to LWS_MAX_SOCKET_IO_BUF
1219                  */
1220
1221                 if (!wsi->protocol->rx_buffer_size &&
1222                                         wsi->u.ws.rx_ubuf_head !=
1223                                                           LWS_MAX_SOCKET_IO_BUF)
1224                         break;
1225                 else
1226                         if (wsi->protocol->rx_buffer_size &&
1227                                         wsi->u.ws.rx_ubuf_head !=
1228                                                   wsi->protocol->rx_buffer_size)
1229                         break;
1230
1231                 /* spill because we filled our rx buffer */
1232 spill:
1233                 /*
1234                  * is this frame a control packet we should take care of at this
1235                  * layer?  If so service it and hide it from the user callback
1236                  */
1237
1238                 lwsl_parser("spill on %s\n", wsi->protocol->name);
1239
1240                 switch (wsi->u.ws.opcode) {
1241                 case LWSWSOPC_CLOSE:
1242
1243                         /* is this an acknowledgement of our close? */
1244                         if (wsi->state == LWSS_AWAITING_CLOSE_ACK) {
1245                                 /*
1246                                  * fine he has told us he is closing too, let's
1247                                  * finish our close
1248                                  */
1249                                 lwsl_parser("seen client close ack\n");
1250                                 return -1;
1251                         }
1252                         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
1253                                 /* if he sends us 2 CLOSE, kill him */
1254                                 return -1;
1255
1256                         if (user_callback_handle_rxflow(
1257                                         wsi->protocol->callback, wsi,
1258                                         LWS_CALLBACK_WS_PEER_INITIATED_CLOSE,
1259                                         wsi->user_space,
1260                                         &wsi->u.ws.rx_ubuf[LWS_PRE],
1261                                         wsi->u.ws.rx_ubuf_head))
1262                                 return -1;
1263
1264                         lwsl_parser("server sees client close packet\n");
1265                         wsi->state = LWSS_RETURNED_CLOSE_ALREADY;
1266                         /* deal with the close packet contents as a PONG */
1267                         wsi->u.ws.payload_is_close = 1;
1268                         goto process_as_ping;
1269
1270                 case LWSWSOPC_PING:
1271                         lwsl_info("received %d byte ping, sending pong\n",
1272                                                  wsi->u.ws.rx_ubuf_head);
1273
1274                         if (wsi->u.ws.ping_pending_flag) {
1275                                 /*
1276                                  * there is already a pending ping payload
1277                                  * we should just log and drop
1278                                  */
1279                                 lwsl_parser("DROP PING since one pending\n");
1280                                 goto ping_drop;
1281                         }
1282 process_as_ping:
1283                         /* control packets can only be < 128 bytes long */
1284                         if (wsi->u.ws.rx_ubuf_head > 128 - 3) {
1285                                 lwsl_parser("DROP PING payload too large\n");
1286                                 goto ping_drop;
1287                         }
1288
1289                         /* stash the pong payload */
1290                         memcpy(wsi->u.ws.ping_payload_buf + LWS_PRE,
1291                                &wsi->u.ws.rx_ubuf[LWS_PRE],
1292                                 wsi->u.ws.rx_ubuf_head);
1293
1294                         wsi->u.ws.ping_payload_len = wsi->u.ws.rx_ubuf_head;
1295                         wsi->u.ws.ping_pending_flag = 1;
1296
1297                         /* get it sent as soon as possible */
1298                         lws_callback_on_writable(wsi);
1299 ping_drop:
1300                         wsi->u.ws.rx_ubuf_head = 0;
1301                         return 0;
1302
1303                 case LWSWSOPC_PONG:
1304                         lwsl_info("received pong\n");
1305                         lwsl_hexdump(&wsi->u.ws.rx_ubuf[LWS_PRE],
1306                                      wsi->u.ws.rx_ubuf_head);
1307
1308                         /* issue it */
1309                         callback_action = LWS_CALLBACK_RECEIVE_PONG;
1310                         break;
1311
1312                 case LWSWSOPC_TEXT_FRAME:
1313                 case LWSWSOPC_BINARY_FRAME:
1314                 case LWSWSOPC_CONTINUATION:
1315                         break;
1316
1317                 default:
1318                         lwsl_parser("passing opc %x up to exts\n",
1319                                     wsi->u.ws.opcode);
1320                         /*
1321                          * It's something special we can't understand here.
1322                          * Pass the payload up to the extension's parsing
1323                          * state machine.
1324                          */
1325
1326                         eff_buf.token = &wsi->u.ws.rx_ubuf[LWS_PRE];
1327                         eff_buf.token_len = wsi->u.ws.rx_ubuf_head;
1328
1329                         if (lws_ext_cb_active(wsi, LWS_EXT_CB_EXTENDED_PAYLOAD_RX,
1330                                         &eff_buf, 0) <= 0) /* not handle or fail */
1331                                 lwsl_ext("ext opc opcode 0x%x unknown\n",
1332                                                               wsi->u.ws.opcode);
1333
1334                         wsi->u.ws.rx_ubuf_head = 0;
1335                         return 0;
1336                 }
1337
1338                 /*
1339                  * No it's real payload, pass it up to the user callback.
1340                  * It's nicely buffered with the pre-padding taken care of
1341                  * so it can be sent straight out again using lws_write
1342                  */
1343
1344                 eff_buf.token = &wsi->u.ws.rx_ubuf[LWS_PRE];
1345                 eff_buf.token_len = wsi->u.ws.rx_ubuf_head;
1346
1347 drain_extension:
1348                 lwsl_ext("%s: passing %d to ext\n", __func__, eff_buf.token_len);
1349
1350                 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
1351                     wsi->state == LWSS_AWAITING_CLOSE_ACK)
1352                         goto already_done;
1353
1354                 n = lws_ext_cb_active(wsi, LWS_EXT_CB_PAYLOAD_RX, &eff_buf, 0);
1355                 if (n < 0) {
1356                         /*
1357                          * we may rely on this to get RX, just drop connection
1358                          */
1359                         wsi->socket_is_permanently_unusable = 1;
1360                         return -1;
1361                 }
1362
1363                 if (rx_draining_ext && eff_buf.token_len == 0)
1364                         goto already_done;
1365
1366                 if (n && eff_buf.token_len) {
1367                         /* extension had more... main loop will come back */
1368                         wsi->u.ws.rx_draining_ext = 1;
1369                         wsi->u.ws.rx_draining_ext_list = pt->rx_draining_ext_list;
1370                         pt->rx_draining_ext_list = wsi;
1371                 }
1372
1373                 if (eff_buf.token_len > 0 ||
1374                     callback_action == LWS_CALLBACK_RECEIVE_PONG) {
1375                         eff_buf.token[eff_buf.token_len] = '\0';
1376
1377                         if (wsi->protocol->callback) {
1378
1379                                 if (callback_action == LWS_CALLBACK_RECEIVE_PONG)
1380                                         lwsl_info("Doing pong callback\n");
1381
1382                                 ret = user_callback_handle_rxflow(
1383                                                 wsi->protocol->callback,
1384                                                 wsi,
1385                                                 (enum lws_callback_reasons)callback_action,
1386                                                 wsi->user_space,
1387                                                 eff_buf.token,
1388                                                 eff_buf.token_len);
1389                         }
1390                         else
1391                                 lwsl_err("No callback on payload spill!\n");
1392                 }
1393
1394 already_done:
1395                 wsi->u.ws.rx_ubuf_head = 0;
1396                 break;
1397         }
1398
1399         return ret;
1400
1401 illegal_ctl_length:
1402
1403         lwsl_warn("Control frame with xtended length is illegal\n");
1404         /* kill the connection */
1405         return -1;
1406 }
1407
1408
1409 /**
1410  * lws_remaining_packet_payload() - Bytes to come before "overall"
1411  *                                            rx packet is complete
1412  * @wsi:                Websocket instance (available from user callback)
1413  *
1414  *      This function is intended to be called from the callback if the
1415  *  user code is interested in "complete packets" from the client.
1416  *  libwebsockets just passes through payload as it comes and issues a buffer
1417  *  additionally when it hits a built-in limit.  The LWS_CALLBACK_RECEIVE
1418  *  callback handler can use this API to find out if the buffer it has just
1419  *  been given is the last piece of a "complete packet" from the client --
1420  *  when that is the case lws_remaining_packet_payload() will return
1421  *  0.
1422  *
1423  *  Many protocols won't care becuse their packets are always small.
1424  */
1425
1426 LWS_VISIBLE size_t
1427 lws_remaining_packet_payload(struct lws *wsi)
1428 {
1429         return wsi->u.ws.rx_packet_length;
1430 }