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