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