lib/parsers.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2013 Andy Green <andy@warmcat.com>
   5  *
   6  *  This library is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU Lesser General Public
   8  *  License as published by the Free Software Foundation:
   9  *  version 2.1 of the License.
  10  *
  11  *  This library is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  *  Lesser General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Lesser General Public
  17  *  License along with this library; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "private-libwebsockets.h"
  23
  24 unsigned char lextable[] = {
  25         #include "lextable.h"
  26 };
  27
  28 #define FAIL_CHAR 0x08
  29
  30 int lextable_decode(int pos, char c)
  31 {
  32         c = tolower(c);
  33
  34         while (1) {
  35                 if (lextable[pos] & (1 << 7)) { /* 1-byte, fail on mismatch */
  36                         if ((lextable[pos] & 0x7f) != c)
  37                                 return -1;
  38                         /* fall thru */
  39                         pos++;
  40                         if (lextable[pos] == FAIL_CHAR)
  41                                 return -1;
  42                         return pos;
  43                 }
  44
  45                 if (lextable[pos] == FAIL_CHAR)
  46                         return -1;
  47
  48                 /* b7 = 0, end or 3-byte */
  49                 if (lextable[pos] < FAIL_CHAR) /* terminal marker */
  50                         return pos;
  51
  52                 if (lextable[pos] == c) /* goto */
  53                         return pos + (lextable[pos + 1]) +
  54                                                 (lextable[pos + 2] << 8);
  55                 /* fall thru goto */
  56                 pos += 3;
  57                 /* continue */
  58         }
  59 }
  60
  61 int lws_allocate_header_table(struct lws *wsi)
  62 {
  63         struct lws_context *context = wsi->context;
  64         int n;
  65
  66         lwsl_debug("%s: wsi %p: ah %p\n", __func__, (void *)wsi,
  67                  (void *)wsi->u.hdr.ah);
  68
  69         /* if we are already bound to one, just clear it down */
  70         if (wsi->u.hdr.ah)
  71                 goto reset;
  72         /*
  73          * server should have suppressed the accept of a new wsi before this
  74          * became the case.  If initiating multiple client connects, make sure
  75          * the ah pool is big enough to cope, or be prepared to retry
  76          */
  77         if (context->ah_count_in_use == context->max_http_header_pool) {
  78                 lwsl_err("No free ah\n");
  79                 return -1;
  80         }
  81
  82         for (n = 0; n < context->max_http_header_pool; n++)
  83                 if (!context->ah_pool[n].in_use)
  84                         break;
  85
  86         /* if the count of in use said something free... */
  87         assert(n != context->max_http_header_pool);
  88
  89         wsi->u.hdr.ah = &context->ah_pool[n];
  90         wsi->u.hdr.ah->in_use = 1;
  91
  92         context->ah_count_in_use++;
  93         /* if we used up all the ah, defeat accepting new server connections */
  94         if (context->ah_count_in_use == context->max_http_header_pool)
  95                 if (_lws_server_listen_accept_flow_control(context, 0))
  96                         return 1;
  97
  98         lwsl_debug("%s: wsi %p: ah %p: count %d (on exit)\n",
  99                  __func__, (void *)wsi, (void *)wsi->u.hdr.ah,
 100                  context->ah_count_in_use);
 101
 102 reset:
 103         /* init the ah to reflect no headers or data have appeared yet */
 104         memset(wsi->u.hdr.ah->frag_index, 0, sizeof(wsi->u.hdr.ah->frag_index));
 105         wsi->u.hdr.ah->nfrag = 0;
 106         wsi->u.hdr.ah->pos = 0;
 107
 108         return 0;
 109 }
 110
 111 int lws_free_header_table(struct lws *wsi)
 112 {
 113         struct lws_context *context = wsi->context;
 114
 115         lwsl_debug("%s: wsi %p: ah %p (count = %d)\n", __func__, (void *)wsi,
 116                  (void *)wsi->u.hdr.ah, context->ah_count_in_use);
 117
 118         assert(wsi->u.hdr.ah);
 119         if (!wsi->u.hdr.ah)
 120                 return 0;
 121
 122         /* if we think we're freeing one, there should be one to free */
 123         assert(context->ah_count_in_use > 0);
 124
 125         assert(wsi->u.hdr.ah->in_use);
 126         wsi->u.hdr.ah->in_use = 0;
 127
 128         /* if we just freed up one ah, allow new server connection */
 129         if (context->ah_count_in_use == context->max_http_header_pool)
 130                 if (_lws_server_listen_accept_flow_control(context, 1))
 131                         return 1;
 132
 133         context->ah_count_in_use--;
 134         wsi->u.hdr.ah = NULL;
 135
 136         return 0;
 137 }
 138
 139 /**
 140  * lws_hdr_fragment_length: report length of a single fragment of a header
 141  *              The returned length does not include the space for a
 142  *              terminating '\0'
 143  *
 144  * @wsi: websocket connection
 145  * @h: which header index we are interested in
 146  * @frag_idx: which fragment of @h we want to get the length of
 147  */
 148
 149 LWS_VISIBLE int
 150 lws_hdr_fragment_length(struct lws *wsi, enum lws_token_indexes h, int frag_idx)
 151 {
 152         int n;
 153
 154         n = wsi->u.hdr.ah->frag_index[h];
 155         if (!n)
 156                 return 0;
 157         do {
 158                 if (!frag_idx)
 159                         return wsi->u.hdr.ah->frags[n].len;
 160                 n = wsi->u.hdr.ah->frags[n].nfrag;
 161         } while (frag_idx-- && n);
 162
 163         return 0;
 164 }
 165
 166 /**
 167  * lws_hdr_total_length: report length of all fragments of a header totalled up
 168  *              The returned length does not include the space for a
 169  *              terminating '\0'
 170  *
 171  * @wsi: websocket connection
 172  * @h: which header index we are interested in
 173  */
 174
 175 LWS_VISIBLE int lws_hdr_total_length(struct lws *wsi, enum lws_token_indexes h)
 176 {
 177         int n;
 178         int len = 0;
 179
 180         n = wsi->u.hdr.ah->frag_index[h];
 181         if (!n)
 182                 return 0;
 183         do {
 184                 len += wsi->u.hdr.ah->frags[n].len;
 185                 n = wsi->u.hdr.ah->frags[n].nfrag;
 186         } while (n);
 187
 188         return len;
 189 }
 190
 191 /**
 192  * lws_hdr_copy_fragment: copy a single fragment of the given header to a buffer
 193  *              The buffer length @len must include space for an additional
 194  *              terminating '\0', or it will fail returning -1.
 195  *              If the requested fragment index is not present, it fails
 196  *              returning -1.
 197  *
 198  * @wsi: websocket connection
 199  * @dst: destination buffer
 200  * @len: length of destination buffer
 201  * @h: which header index we are interested in
 202  * @frag_index: which fragment of @h we want to copy
 203  */
 204
 205 LWS_VISIBLE int lws_hdr_copy_fragment(struct lws *wsi, char *dst, int len,
 206                                       enum lws_token_indexes h, int frag_idx)
 207 {
 208         int n = 0;
 209         int f = wsi->u.hdr.ah->frag_index[h];
 210
 211         while (n < frag_idx) {
 212                 f = wsi->u.hdr.ah->frags[f].nfrag;
 213                 if (!f)
 214                         return -1;
 215                 n++;
 216         }
 217
 218         if (wsi->u.hdr.ah->frags[f].len >= len)
 219                 return -1;
 220
 221         memcpy(dst, wsi->u.hdr.ah->data + wsi->u.hdr.ah->frags[f].offset,
 222                wsi->u.hdr.ah->frags[f].len);
 223         dst[wsi->u.hdr.ah->frags[f].len] = '\0';
 224
 225         return wsi->u.hdr.ah->frags[f].len;
 226 }
 227
 228 /**
 229  * lws_hdr_copy: copy a single fragment of the given header to a buffer
 230  *              The buffer length @len must include space for an additional
 231  *              terminating '\0', or it will fail returning -1.
 232  *
 233  * @wsi: websocket connection
 234  * @dst: destination buffer
 235  * @len: length of destination buffer
 236  * @h: which header index we are interested in
 237  */
 238
 239 LWS_VISIBLE int lws_hdr_copy(struct lws *wsi, char *dst, int len,
 240                              enum lws_token_indexes h)
 241 {
 242         int toklen = lws_hdr_total_length(wsi, h);
 243         int n;
 244
 245         if (toklen >= len)
 246                 return -1;
 247
 248         n = wsi->u.hdr.ah->frag_index[h];
 249         if (!n)
 250                 return 0;
 251
 252         do {
 253                 strcpy(dst, &wsi->u.hdr.ah->data[wsi->u.hdr.ah->frags[n].offset]);
 254                 dst += wsi->u.hdr.ah->frags[n].len;
 255                 n = wsi->u.hdr.ah->frags[n].nfrag;
 256         } while (n);
 257
 258         return toklen;
 259 }
 260
 261 char *lws_hdr_simple_ptr(struct lws *wsi, enum lws_token_indexes h)
 262 {
 263         int n;
 264
 265         n = wsi->u.hdr.ah->frag_index[h];
 266         if (!n)
 267                 return NULL;
 268
 269         return wsi->u.hdr.ah->data + wsi->u.hdr.ah->frags[n].offset;
 270 }
 271
 272 int lws_hdr_simple_create(struct lws *wsi, enum lws_token_indexes h,
 273                           const char *s)
 274 {
 275         wsi->u.hdr.ah->nfrag++;
 276         if (wsi->u.hdr.ah->nfrag == ARRAY_SIZE(wsi->u.hdr.ah->frags)) {
 277                 lwsl_warn("More hdr frags than we can deal with, dropping\n");
 278                 return -1;
 279         }
 280
 281         wsi->u.hdr.ah->frag_index[h] = wsi->u.hdr.ah->nfrag;
 282
 283         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].offset = wsi->u.hdr.ah->pos;
 284         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len = 0;
 285         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].nfrag = 0;
 286
 287         do {
 288                 if (wsi->u.hdr.ah->pos == wsi->context->max_http_header_data) {
 289                         lwsl_err("Ran out of header data space\n");
 290                         return -1;
 291                 }
 292                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = *s;
 293                 if (*s)
 294                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len++;
 295         } while (*s++);
 296
 297         return 0;
 298 }
 299
 300 static signed char char_to_hex(const char c)
 301 {
 302         if (c >= '0' && c <= '9')
 303                 return c - '0';
 304
 305         if (c >= 'a' && c <= 'f')
 306                 return c - 'a' + 10;
 307
 308         if (c >= 'A' && c <= 'F')
 309                 return c - 'A' + 10;
 310
 311         return -1;
 312 }
 313
 314 static int issue_char(struct lws *wsi, unsigned char c)
 315 {
 316         unsigned short frag_len;
 317
 318         if (wsi->u.hdr.ah->pos == wsi->context->max_http_header_data) {
 319                 lwsl_warn("excessive header content\n");
 320                 return -1;
 321         }
 322
 323         frag_len = wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len;
 324         /*
 325          * If we haven't hit the token limit, just copy the character into
 326          * the header
 327          */
 328         if (frag_len < wsi->u.hdr.current_token_limit) {
 329                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = c;
 330                 if (c)
 331                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len++;
 332                 return 0;
 333         }
 334
 335         /* Insert a null character when we *hit* the limit: */
 336         if (frag_len == wsi->u.hdr.current_token_limit) {
 337                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 338                 lwsl_warn("header %i exceeds limit %d\n",
 339                           wsi->u.hdr.parser_state, wsi->u.hdr.current_token_limit);
 340         }
 341
 342         return 1;
 343 }
 344
 345 int lws_parse(struct lws *wsi, unsigned char c)
 346 {
 347         static const unsigned char methods[] = {
 348                 WSI_TOKEN_GET_URI,
 349                 WSI_TOKEN_POST_URI,
 350                 WSI_TOKEN_OPTIONS_URI,
 351                 WSI_TOKEN_PUT_URI,
 352                 WSI_TOKEN_PATCH_URI,
 353                 WSI_TOKEN_DELETE_URI,
 354         };
 355         struct allocated_headers *ah = wsi->u.hdr.ah;
 356         struct lws_context *context = wsi->context;
 357         unsigned int n, m, enc = 0;
 358
 359         switch (wsi->u.hdr.parser_state) {
 360         default:
 361
 362                 lwsl_parser("WSI_TOK_(%d) '%c'\n", wsi->u.hdr.parser_state, c);
 363
 364                 /* collect into malloc'd buffers */
 365                 /* optional initial space swallow */
 366                 if (!ah->frags[ah->frag_index[
 367                                       wsi->u.hdr.parser_state]].len && c == ' ')
 368                         break;
 369
 370                 for (m = 0; m < ARRAY_SIZE(methods); m++)
 371                         if (wsi->u.hdr.parser_state == methods[m])
 372                                 break;
 373                 if (m == ARRAY_SIZE(methods))
 374                         /* it was not any of the methods */
 375                         goto check_eol;
 376
 377                 /* special URI processing... end at space */
 378
 379                 if (c == ' ') {
 380                         /* enforce starting with / */
 381                         if (!ah->frags[ah->nfrag].len)
 382                                 if (issue_char(wsi, '/') < 0)
 383                                         return -1;
 384
 385                         /* begin parsing HTTP version: */
 386                         if (issue_char(wsi, '\0') < 0)
 387                                 return -1;
 388                         wsi->u.hdr.parser_state = WSI_TOKEN_HTTP;
 389                         goto start_fragment;
 390                 }
 391
 392                 /* special URI processing... convert %xx */
 393
 394                 switch (wsi->u.hdr.ues) {
 395                 case URIES_IDLE:
 396                         if (c == '%') {
 397                                 wsi->u.hdr.ues = URIES_SEEN_PERCENT;
 398                                 goto swallow;
 399                         }
 400                         break;
 401                 case URIES_SEEN_PERCENT:
 402                         if (char_to_hex(c) < 0) {
 403                                 /* regurgitate */
 404                                 if (issue_char(wsi, '%') < 0)
 405                                         return -1;
 406                                 wsi->u.hdr.ues = URIES_IDLE;
 407                                 /* continue on to assess c */
 408                                 break;
 409                         }
 410                         wsi->u.hdr.esc_stash = c;
 411                         wsi->u.hdr.ues = URIES_SEEN_PERCENT_H1;
 412                         goto swallow;
 413
 414                 case URIES_SEEN_PERCENT_H1:
 415                         if (char_to_hex(c) < 0) {
 416                                 /* regurgitate */
 417                                 issue_char(wsi, '%');
 418                                 wsi->u.hdr.ues = URIES_IDLE;
 419                                 /* regurgitate + assess */
 420                                 if (lws_parse(wsi, wsi->u.hdr.esc_stash) < 0)
 421                                         return -1;
 422                                 /* continue on to assess c */
 423                                 break;
 424                         }
 425                         c = (char_to_hex(wsi->u.hdr.esc_stash) << 4) |
 426                                         char_to_hex(c);
 427                         enc = 1;
 428                         wsi->u.hdr.ues = URIES_IDLE;
 429                         break;
 430                 }
 431
 432                 /*
 433                  * special URI processing...
 434                  *  convert /.. or /... or /../ etc to /
 435                  *  convert /./ to /
 436                  *  convert // or /// etc to /
 437                  *  leave /.dir or whatever alone
 438                  */
 439
 440                 switch (wsi->u.hdr.ups) {
 441                 case URIPS_IDLE:
 442                         /* genuine delimiter */
 443                         if ((c == '&' || c == ';') && !enc) {
 444                                 issue_char(wsi, c);
 445                                 /* swallow the terminator */
 446                                 ah->frags[ah->nfrag].len--;
 447                                 /* link to next fragment */
 448                                 ah->frags[ah->nfrag].nfrag = ah->nfrag + 1;
 449                                 ah->nfrag++;
 450                                 if (ah->nfrag >= ARRAY_SIZE(ah->frags))
 451                                         goto excessive;
 452                                 /* start next fragment after the & */
 453                                 wsi->u.hdr.post_literal_equal = 0;
 454                                 ah->frags[ah->nfrag].offset = ah->pos;
 455                                 ah->frags[ah->nfrag].len = 0;
 456                                 ah->frags[ah->nfrag].nfrag = 0;
 457                                 goto swallow;
 458                         }
 459                         /* uriencoded = in the name part, disallow */
 460                         if (c == '=' && enc && !wsi->u.hdr.post_literal_equal)
 461                                 c = '_';
 462
 463                         /* after the real =, we don't care how many = */
 464                         if (c == '=' && !enc)
 465                                 wsi->u.hdr.post_literal_equal = 1;
 466
 467                         /* + to space */
 468                         if (c == '+' && !enc)
 469                                 c = ' ';
 470                         /* issue the first / always */
 471                         if (c == '/' && !ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS])
 472                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 473                         break;
 474                 case URIPS_SEEN_SLASH:
 475                         /* swallow subsequent slashes */
 476                         if (c == '/')
 477                                 goto swallow;
 478                         /* track and swallow the first . after / */
 479                         if (c == '.') {
 480                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT;
 481                                 goto swallow;
 482                         }
 483                         wsi->u.hdr.ups = URIPS_IDLE;
 484                         break;
 485                 case URIPS_SEEN_SLASH_DOT:
 486                         /* swallow second . */
 487                         if (c == '.') {
 488                                 /*
 489                                  * back up one dir level if possible
 490                                  * safe against header fragmentation because
 491                                  * the method URI can only be in 1 fragment
 492                                  */
 493                                 if (ah->frags[ah->nfrag].len > 2) {
 494                                         ah->pos--;
 495                                         ah->frags[ah->nfrag].len--;
 496                                         do {
 497                                                 ah->pos--;
 498                                                 ah->frags[ah->nfrag].len--;
 499                                         } while (ah->frags[ah->nfrag].len > 1 &&
 500                                                  ah->data[ah->pos] != '/');
 501                                 }
 502                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT_DOT;
 503                                 goto swallow;
 504                         }
 505                         /* change /./ to / */
 506                         if (c == '/') {
 507                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 508                                 goto swallow;
 509                         }
 510                         /* it was like /.dir ... regurgitate the . */
 511                         wsi->u.hdr.ups = URIPS_IDLE;
 512                         if (issue_char(wsi, '.') < 0)
 513                                 return -1;
 514                         break;
 515
 516                 case URIPS_SEEN_SLASH_DOT_DOT:
 517                         /* swallow prior .. chars and any subsequent . */
 518                         if (c == '.')
 519                                 goto swallow;
 520                         /* last issued was /, so another / == // */
 521                         if (c == '/')
 522                                 goto swallow;
 523                         /* last we issued was / so SEEN_SLASH */
 524                         wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 525                         break;
 526                 }
 527
 528                 if (c == '?' && !enc &&
 529                     !ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS]) { /* start of URI arguments */
 530                         /* seal off uri header */
 531                         ah->data[ah->pos++] = '\0';
 532
 533                         /* move to using WSI_TOKEN_HTTP_URI_ARGS */
 534                         ah->nfrag++;
 535                         if (ah->nfrag >= ARRAY_SIZE(ah->frags))
 536                                 goto excessive;
 537                         ah->frags[ah->nfrag].offset = ah->pos;
 538                         ah->frags[ah->nfrag].len = 0;
 539                         ah->frags[ah->nfrag].nfrag = 0;
 540
 541                         wsi->u.hdr.post_literal_equal = 0;
 542                         ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS] = ah->nfrag;
 543                         wsi->u.hdr.ups = URIPS_IDLE;
 544                         goto swallow;
 545                 }
 546
 547 check_eol:
 548
 549                 /* bail at EOL */
 550                 if (wsi->u.hdr.parser_state != WSI_TOKEN_CHALLENGE &&
 551                                                                   c == '\x0d') {
 552                         c = '\0';
 553                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 554                         lwsl_parser("*\n");
 555                 }
 556
 557                 n = issue_char(wsi, c);
 558                 if ((int)n < 0)
 559                         return -1;
 560                 if (n > 0)
 561                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 562
 563 swallow:
 564                 /* per-protocol end of headers management */
 565
 566                 if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 567                         goto set_parsing_complete;
 568                 break;
 569
 570                 /* collecting and checking a name part */
 571         case WSI_TOKEN_NAME_PART:
 572                 lwsl_parser("WSI_TOKEN_NAME_PART '%c' (mode=%d)\n", c, wsi->mode);
 573
 574                 wsi->u.hdr.lextable_pos =
 575                                 lextable_decode(wsi->u.hdr.lextable_pos, c);
 576                 /*
 577                  * Server needs to look out for unknown methods...
 578                  */
 579                 if (wsi->u.hdr.lextable_pos < 0 &&
 580                     wsi->mode == LWSCM_HTTP_SERVING) {
 581                         /* this is not a header we know about */
 582                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 583                                 if (ah->frag_index[methods[m]]) {
 584                                         /*
 585                                          * already had the method, no idea what
 586                                          * this crap from the client is, ignore
 587                                          */
 588                                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 589                                         break;
 590                                 }
 591                         /*
 592                          * hm it's an unknown http method from a client in fact,
 593                          * treat as dangerous
 594                          */
 595                         if (m == ARRAY_SIZE(methods)) {
 596                                 lwsl_info("Unknown method - dropping\n");
 597                                 return -1;
 598                         }
 599                         break;
 600                 }
 601                 /*
 602                  * ...otherwise for a client, let him ignore unknown headers
 603                  * coming from the server
 604                  */
 605                 if (wsi->u.hdr.lextable_pos < 0) {
 606                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 607                         break;
 608                 }
 609
 610                 if (lextable[wsi->u.hdr.lextable_pos] < FAIL_CHAR) {
 611                         /* terminal state */
 612
 613                         n = ((unsigned int)lextable[wsi->u.hdr.lextable_pos] << 8) |
 614                                         lextable[wsi->u.hdr.lextable_pos + 1];
 615
 616                         lwsl_parser("known hdr %d\n", n);
 617                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 618                                 if (n == methods[m] &&
 619                                                 ah->frag_index[
 620                                                         methods[m]]) {
 621                                         lwsl_warn("Duplicated method\n");
 622                                         return -1;
 623                                 }
 624
 625                         /*
 626                          * WSORIGIN is protocol equiv to ORIGIN,
 627                          * JWebSocket likes to send it, map to ORIGIN
 628                          */
 629                         if (n == WSI_TOKEN_SWORIGIN)
 630                                 n = WSI_TOKEN_ORIGIN;
 631
 632                         wsi->u.hdr.parser_state = (enum lws_token_indexes)
 633                                                         (WSI_TOKEN_GET_URI + n);
 634
 635                         if (context->token_limits)
 636                                 wsi->u.hdr.current_token_limit =
 637                                         context->token_limits->token_limit[
 638                                                        wsi->u.hdr.parser_state];
 639                         else
 640                                 wsi->u.hdr.current_token_limit =
 641                                         wsi->context->max_http_header_data;
 642
 643                         if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 644                                 goto set_parsing_complete;
 645
 646                         goto start_fragment;
 647                 }
 648                 break;
 649
 650 start_fragment:
 651                 ah->nfrag++;
 652 excessive:
 653                 if (ah->nfrag == ARRAY_SIZE(ah->frags)) {
 654                         lwsl_warn("More hdr frags than we can deal with\n");
 655                         return -1;
 656                 }
 657
 658                 ah->frags[ah->nfrag].offset = ah->pos;
 659                 ah->frags[ah->nfrag].len = 0;
 660                 ah->frags[ ah->nfrag].nfrag = 0;
 661
 662                 n = ah->frag_index[wsi->u.hdr.parser_state];
 663                 if (!n) { /* first fragment */
 664                         ah->frag_index[wsi->u.hdr.parser_state] = ah->nfrag;
 665                         break;
 666                 }
 667                 /* continuation */
 668                 while (ah->frags[n].nfrag)
 669                                 n = ah->frags[n].nfrag;
 670                 ah->frags[n].nfrag = ah->nfrag;
 671
 672                 if (ah->pos == wsi->context->max_http_header_data) {
 673                         lwsl_warn("excessive header content\n");
 674                         return -1;
 675                 }
 676
 677                 ah->data[ah->pos++] = ' ';
 678                 ah->frags[ah->nfrag].len++;
 679                 break;
 680
 681                 /* skipping arg part of a name we didn't recognize */
 682         case WSI_TOKEN_SKIPPING:
 683                 lwsl_parser("WSI_TOKEN_SKIPPING '%c'\n", c);
 684
 685                 if (c == '\x0d')
 686                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 687                 break;
 688
 689         case WSI_TOKEN_SKIPPING_SAW_CR:
 690                 lwsl_parser("WSI_TOKEN_SKIPPING_SAW_CR '%c'\n", c);
 691                 if (c == '\x0a') {
 692                         wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 693                         wsi->u.hdr.lextable_pos = 0;
 694                 } else
 695                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 696                 break;
 697                 /* we're done, ignore anything else */
 698
 699         case WSI_PARSING_COMPLETE:
 700                 lwsl_parser("WSI_PARSING_COMPLETE '%c'\n", c);
 701                 break;
 702         }
 703
 704         return 0;
 705
 706 set_parsing_complete:
 707
 708         if (lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE)) {
 709                 if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION))
 710                         wsi->ietf_spec_revision =
 711                                atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION));
 712
 713                 lwsl_parser("v%02d hdrs completed\n", wsi->ietf_spec_revision);
 714         }
 715         wsi->u.hdr.parser_state = WSI_PARSING_COMPLETE;
 716         wsi->hdr_parsing_completed = 1;
 717
 718         return 0;
 719 }
 720
 721
 722 /**
 723  * lws_frame_is_binary: true if the current frame was sent in binary mode
 724  *
 725  * @wsi: the connection we are inquiring about
 726  *
 727  * This is intended to be called from the LWS_CALLBACK_RECEIVE callback if
 728  * it's interested to see if the frame it's dealing with was sent in binary
 729  * mode.
 730  */
 731
 732 LWS_VISIBLE int lws_frame_is_binary(struct lws *wsi)
 733 {
 734         return wsi->u.ws.frame_is_binary;
 735 }
 736
 737 int
 738 lws_rx_sm(struct lws *wsi, unsigned char c)
 739 {
 740         struct lws_tokens eff_buf;
 741         int ret = 0, n, rx_draining_ext = 0;
 742         int callback_action = LWS_CALLBACK_RECEIVE;
 743         if (wsi->socket_is_permanently_unusable)
 744                 return -1;
 745
 746         switch (wsi->lws_rx_parse_state) {
 747         case LWS_RXPS_NEW:
 748                 if (wsi->u.ws.rx_draining_ext) {
 749                         struct lws **w = &wsi->context->rx_draining_ext_list;
 750
 751                         eff_buf.token = NULL;
 752                         eff_buf.token_len = 0;
 753                         wsi->u.ws.rx_draining_ext = 0;
 754                         /* remove us from context draining ext list */
 755                         while (*w) {
 756                                 if (*w == wsi) {
 757                                         *w = wsi->u.ws.rx_draining_ext_list;
 758                                         break;
 759                                 }
 760                                 w = &((*w)->u.ws.rx_draining_ext_list);
 761                         }
 762                         wsi->u.ws.rx_draining_ext_list = NULL;
 763                         rx_draining_ext = 1;
 764                         lwsl_err("%s: doing draining flow\n", __func__);
 765
 766                         goto drain_extension;
 767                 }
 768                 switch (wsi->ietf_spec_revision) {
 769                 case 13:
 770                         /*
 771                          * no prepended frame key any more
 772                          */
 773                         wsi->u.ws.all_zero_nonce = 1;
 774                         goto handle_first;
 775
 776                 default:
 777                         lwsl_warn("lws_rx_sm: unknown spec version %d\n",
 778                                                        wsi->ietf_spec_revision);
 779                         break;
 780                 }
 781                 break;
 782         case LWS_RXPS_04_mask_1:
 783                 wsi->u.ws.mask[1] = c;
 784                 if (c)
 785                         wsi->u.ws.all_zero_nonce = 0;
 786                 wsi->lws_rx_parse_state = LWS_RXPS_04_mask_2;
 787                 break;
 788         case LWS_RXPS_04_mask_2:
 789                 wsi->u.ws.mask[2] = c;
 790                 if (c)
 791                         wsi->u.ws.all_zero_nonce = 0;
 792                 wsi->lws_rx_parse_state = LWS_RXPS_04_mask_3;
 793                 break;
 794         case LWS_RXPS_04_mask_3:
 795                 wsi->u.ws.mask[3] = c;
 796                 if (c)
 797                         wsi->u.ws.all_zero_nonce = 0;
 798
 799                 /*
 800                  * start from the zero'th byte in the XOR key buffer since
 801                  * this is the start of a frame with a new key
 802                  */
 803
 804                 wsi->u.ws.mask_idx = 0;
 805
 806                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
 807                 break;
 808
 809         /*
 810          *  04 logical framing from the spec (all this is masked when incoming
 811          *  and has to be unmasked)
 812          *
 813          * We ignore the possibility of extension data because we don't
 814          * negotiate any extensions at the moment.
 815          *
 816          *    0                   1                   2                   3
 817          *    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
 818          *   +-+-+-+-+-------+-+-------------+-------------------------------+
 819          *   |F|R|R|R| opcode|R| Payload len |    Extended payload length    |
 820          *   |I|S|S|S|  (4)  |S|     (7)     |             (16/63)           |
 821          *   |N|V|V|V|       |V|             |   (if payload len==126/127)   |
 822          *   | |1|2|3|       |4|             |                               |
 823          *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 824          *   |     Extended payload length continued, if payload len == 127  |
 825          *   + - - - - - - - - - - - - - - - +-------------------------------+
 826          *   |                               |         Extension data        |
 827          *   +-------------------------------+ - - - - - - - - - - - - - - - +
 828          *   :                                                               :
 829          *   +---------------------------------------------------------------+
 830          *   :                       Application data                        :
 831          *   +---------------------------------------------------------------+
 832          *
 833          *  We pass payload through to userland as soon as we get it, ignoring
 834          *  FIN.  It's up to userland to buffer it up if it wants to see a
 835          *  whole unfragmented block of the original size (which may be up to
 836          *  2^63 long!)
 837          */
 838
 839         case LWS_RXPS_04_FRAME_HDR_1:
 840 handle_first:
 841
 842                 wsi->u.ws.opcode = c & 0xf;
 843                 wsi->u.ws.rsv = c & 0x70;
 844                 wsi->u.ws.final = !!((c >> 7) & 1);
 845
 846                 switch (wsi->u.ws.opcode) {
 847                 case LWSWSOPC_TEXT_FRAME:
 848                 case LWSWSOPC_BINARY_FRAME:
 849                         wsi->u.ws.rsv_first_msg = (c & 0x70);
 850                         wsi->u.ws.frame_is_binary =
 851                              wsi->u.ws.opcode == LWSWSOPC_BINARY_FRAME;
 852                         break;
 853                 case 3:
 854                 case 4:
 855                 case 5:
 856                 case 6:
 857                 case 7:
 858                 case 0xb:
 859                 case 0xc:
 860                 case 0xd:
 861                 case 0xe:
 862                 case 0xf:
 863                         lwsl_info("illegal opcode\n");
 864                         return -1;
 865                 }
 866                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN;
 867                 break;
 868
 869         case LWS_RXPS_04_FRAME_HDR_LEN:
 870
 871                 wsi->u.ws.this_frame_masked = !!(c & 0x80);
 872
 873                 switch (c & 0x7f) {
 874                 case 126:
 875                         /* control frames are not allowed to have big lengths */
 876                         if (wsi->u.ws.opcode & 8)
 877                                 goto illegal_ctl_length;
 878
 879                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2;
 880                         break;
 881                 case 127:
 882                         /* control frames are not allowed to have big lengths */
 883                         if (wsi->u.ws.opcode & 8)
 884                                 goto illegal_ctl_length;
 885
 886                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8;
 887                         break;
 888                 default:
 889                         wsi->u.ws.rx_packet_length = c & 0x7f;
 890                         if (wsi->u.ws.this_frame_masked)
 891                                 wsi->lws_rx_parse_state =
 892                                                 LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 893                         else
 894                                 if (wsi->u.ws.rx_packet_length)
 895                                         wsi->lws_rx_parse_state =
 896                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 897                                 else {
 898                                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 899                                         goto spill;
 900                                 }
 901                         break;
 902                 }
 903                 break;
 904
 905         case LWS_RXPS_04_FRAME_HDR_LEN16_2:
 906                 wsi->u.ws.rx_packet_length = c << 8;
 907                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1;
 908                 break;
 909
 910         case LWS_RXPS_04_FRAME_HDR_LEN16_1:
 911                 wsi->u.ws.rx_packet_length |= c;
 912                 if (wsi->u.ws.this_frame_masked)
 913                         wsi->lws_rx_parse_state =
 914                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 915                 else
 916                         wsi->lws_rx_parse_state =
 917                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 918                 break;
 919
 920         case LWS_RXPS_04_FRAME_HDR_LEN64_8:
 921                 if (c & 0x80) {
 922                         lwsl_warn("b63 of length must be zero\n");
 923                         /* kill the connection */
 924                         return -1;
 925                 }
 926 #if defined __LP64__
 927                 wsi->u.ws.rx_packet_length = ((size_t)c) << 56;
 928 #else
 929                 wsi->u.ws.rx_packet_length = 0;
 930 #endif
 931                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7;
 932                 break;
 933
 934         case LWS_RXPS_04_FRAME_HDR_LEN64_7:
 935 #if defined __LP64__
 936                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 48;
 937 #endif
 938                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6;
 939                 break;
 940
 941         case LWS_RXPS_04_FRAME_HDR_LEN64_6:
 942 #if defined __LP64__
 943                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 40;
 944 #endif
 945                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5;
 946                 break;
 947
 948         case LWS_RXPS_04_FRAME_HDR_LEN64_5:
 949 #if defined __LP64__
 950                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 32;
 951 #endif
 952                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4;
 953                 break;
 954
 955         case LWS_RXPS_04_FRAME_HDR_LEN64_4:
 956                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 24;
 957                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3;
 958                 break;
 959
 960         case LWS_RXPS_04_FRAME_HDR_LEN64_3:
 961                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 16;
 962                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2;
 963                 break;
 964
 965         case LWS_RXPS_04_FRAME_HDR_LEN64_2:
 966                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 8;
 967                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1;
 968                 break;
 969
 970         case LWS_RXPS_04_FRAME_HDR_LEN64_1:
 971                 wsi->u.ws.rx_packet_length |= ((size_t)c);
 972                 if (wsi->u.ws.this_frame_masked)
 973                         wsi->lws_rx_parse_state =
 974                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 975                 else
 976                         wsi->lws_rx_parse_state =
 977                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 978                 break;
 979
 980         case LWS_RXPS_07_COLLECT_FRAME_KEY_1:
 981                 wsi->u.ws.mask[0] = c;
 982                 if (c)
 983                         wsi->u.ws.all_zero_nonce = 0;
 984                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2;
 985                 break;
 986
 987         case LWS_RXPS_07_COLLECT_FRAME_KEY_2:
 988                 wsi->u.ws.mask[1] = c;
 989                 if (c)
 990                         wsi->u.ws.all_zero_nonce = 0;
 991                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3;
 992                 break;
 993
 994         case LWS_RXPS_07_COLLECT_FRAME_KEY_3:
 995                 wsi->u.ws.mask[2] = c;
 996                 if (c)
 997                         wsi->u.ws.all_zero_nonce = 0;
 998                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4;
 999                 break;
1000
1001         case LWS_RXPS_07_COLLECT_FRAME_KEY_4:
1002                 wsi->u.ws.mask[3] = c;
1003                 if (c)
1004                         wsi->u.ws.all_zero_nonce = 0;
1005                 wsi->lws_rx_parse_state =
1006                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
1007                 wsi->u.ws.mask_idx = 0;
1008                 if (wsi->u.ws.rx_packet_length == 0) {
1009                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
1010                         goto spill;
1011                 }
1012                 break;
1013
1014
1015         case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
1016
1017                 assert(wsi->u.ws.rx_ubuf);
1018
1019                if (wsi->u.ws.rx_ubuf_head + LWS_PRE + 4 >= wsi->u.ws.rx_ubuf_alloc) {
1020                        lwsl_err("Attempted overflow\n");
1021                        return -1;
1022                }
1023                 if (wsi->u.ws.all_zero_nonce)
1024                         wsi->u.ws.rx_ubuf[LWS_PRE +
1025                                (wsi->u.ws.rx_ubuf_head++)] = c;
1026                 else
1027                         wsi->u.ws.rx_ubuf[LWS_PRE +
1028                                (wsi->u.ws.rx_ubuf_head++)] =
1029                                    c ^ wsi->u.ws.mask[
1030                                             (wsi->u.ws.mask_idx++) & 3];
1031
1032                 if (--wsi->u.ws.rx_packet_length == 0) {
1033                         /* spill because we have the whole frame */
1034                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
1035                         goto spill;
1036                 }
1037
1038                 /*
1039                  * if there's no protocol max frame size given, we are
1040                  * supposed to default to LWS_MAX_SOCKET_IO_BUF
1041                  */
1042
1043                 if (!wsi->protocol->rx_buffer_size &&
1044                                         wsi->u.ws.rx_ubuf_head !=
1045                                                           LWS_MAX_SOCKET_IO_BUF)
1046                         break;
1047                 else
1048                         if (wsi->protocol->rx_buffer_size &&
1049                                         wsi->u.ws.rx_ubuf_head !=
1050                                                   wsi->protocol->rx_buffer_size)
1051                         break;
1052
1053                 /* spill because we filled our rx buffer */
1054 spill:
1055                 /*
1056                  * is this frame a control packet we should take care of at this
1057                  * layer?  If so service it and hide it from the user callback
1058                  */
1059
1060                 lwsl_parser("spill on %s\n", wsi->protocol->name);
1061
1062                 switch (wsi->u.ws.opcode) {
1063                 case LWSWSOPC_CLOSE:
1064
1065                         /* is this an acknowledgement of our close? */
1066                         if (wsi->state == LWSS_AWAITING_CLOSE_ACK) {
1067                                 /*
1068                                  * fine he has told us he is closing too, let's
1069                                  * finish our close
1070                                  */
1071                                 lwsl_parser("seen client close ack\n");
1072                                 return -1;
1073                         }
1074                         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
1075                                 /* if he sends us 2 CLOSE, kill him */
1076                                 return -1;
1077
1078                         if (user_callback_handle_rxflow(
1079                                         wsi->protocol->callback, wsi,
1080                                         LWS_CALLBACK_WS_PEER_INITIATED_CLOSE,
1081                                         wsi->user_space,
1082                                         &wsi->u.ws.rx_ubuf[
1083                                                 LWS_PRE],
1084                                         wsi->u.ws.rx_ubuf_head))
1085                                 return -1;
1086
1087                         lwsl_parser("server sees client close packet\n");
1088                         wsi->state = LWSS_RETURNED_CLOSE_ALREADY;
1089                         /* deal with the close packet contents as a PONG */
1090                         wsi->u.ws.payload_is_close = 1;
1091                         goto process_as_ping;
1092
1093                 case LWSWSOPC_PING:
1094                         lwsl_info("received %d byte ping, sending pong\n",
1095                                                  wsi->u.ws.rx_ubuf_head);
1096
1097                         if (wsi->u.ws.ping_pending_flag) {
1098                                 /*
1099                                  * there is already a pending ping payload
1100                                  * we should just log and drop
1101                                  */
1102                                 lwsl_parser("DROP PING since one pending\n");
1103                                 goto ping_drop;
1104                         }
1105 process_as_ping:
1106                         /* control packets can only be < 128 bytes long */
1107                         if (wsi->u.ws.rx_ubuf_head > 128 - 3) {
1108                                 lwsl_parser("DROP PING payload too large\n");
1109                                 goto ping_drop;
1110                         }
1111
1112                         /* stash the pong payload */
1113                         memcpy(wsi->u.ws.ping_payload_buf + LWS_PRE,
1114                                &wsi->u.ws.rx_ubuf[LWS_PRE],
1115                                 wsi->u.ws.rx_ubuf_head);
1116
1117                         wsi->u.ws.ping_payload_len = wsi->u.ws.rx_ubuf_head;
1118                         wsi->u.ws.ping_pending_flag = 1;
1119
1120                         /* get it sent as soon as possible */
1121                         lws_callback_on_writable(wsi);
1122 ping_drop:
1123                         wsi->u.ws.rx_ubuf_head = 0;
1124                         return 0;
1125
1126                 case LWSWSOPC_PONG:
1127                         lwsl_info("received pong\n");
1128                         lwsl_hexdump(&wsi->u.ws.rx_ubuf[LWS_PRE],
1129                                      wsi->u.ws.rx_ubuf_head);
1130
1131                         /* issue it */
1132                         callback_action = LWS_CALLBACK_RECEIVE_PONG;
1133                         break;
1134
1135                 case LWSWSOPC_TEXT_FRAME:
1136                 case LWSWSOPC_BINARY_FRAME:
1137                 case LWSWSOPC_CONTINUATION:
1138                         break;
1139
1140                 default:
1141                         lwsl_parser("passing opc %x up to exts\n",
1142                                                         wsi->u.ws.opcode);
1143                         /*
1144                          * It's something special we can't understand here.
1145                          * Pass the payload up to the extension's parsing
1146                          * state machine.
1147                          */
1148
1149                         eff_buf.token = &wsi->u.ws.rx_ubuf[LWS_PRE];
1150                         eff_buf.token_len = wsi->u.ws.rx_ubuf_head;
1151
1152                         if (lws_ext_cb_active(wsi, LWS_EXT_CB_EXTENDED_PAYLOAD_RX,
1153                                         &eff_buf, 0) <= 0) /* not handle or fail */
1154                                 lwsl_ext("ext opc opcode 0x%x unknown\n",
1155                                                               wsi->u.ws.opcode);
1156
1157                         wsi->u.ws.rx_ubuf_head = 0;
1158                         return 0;
1159                 }
1160
1161                 /*
1162                  * No it's real payload, pass it up to the user callback.
1163                  * It's nicely buffered with the pre-padding taken care of
1164                  * so it can be sent straight out again using lws_write
1165                  */
1166
1167                 eff_buf.token = &wsi->u.ws.rx_ubuf[LWS_PRE];
1168                 eff_buf.token_len = wsi->u.ws.rx_ubuf_head;
1169
1170 drain_extension:
1171                 lwsl_ext("%s: passing %d to ext\n", __func__, eff_buf.token_len);
1172
1173                 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
1174                     wsi->state == LWSS_AWAITING_CLOSE_ACK)
1175                         goto already_done;
1176
1177                 n = lws_ext_cb_active(wsi, LWS_EXT_CB_PAYLOAD_RX, &eff_buf, 0);
1178                 if (n < 0) {
1179                         /*
1180                          * we may rely on this to get RX, just drop connection
1181                          */
1182                         wsi->socket_is_permanently_unusable = 1;
1183                         return -1;
1184                 }
1185
1186                 if (rx_draining_ext && eff_buf.token_len == 0)
1187                         goto already_done;
1188
1189                 if (n && eff_buf.token_len) {
1190                         /* extension had more... main loop will come back */
1191                         wsi->u.ws.rx_draining_ext = 1;
1192                         wsi->u.ws.rx_draining_ext_list = wsi->context->rx_draining_ext_list;
1193                         wsi->context->rx_draining_ext_list = wsi;
1194                 }
1195
1196                 if (eff_buf.token_len > 0 ||
1197                     callback_action == LWS_CALLBACK_RECEIVE_PONG) {
1198                         eff_buf.token[eff_buf.token_len] = '\0';
1199
1200                         if (wsi->protocol->callback) {
1201
1202                                 if (callback_action == LWS_CALLBACK_RECEIVE_PONG)
1203                                         lwsl_info("Doing pong callback\n");
1204
1205                                 ret = user_callback_handle_rxflow(
1206                                                 wsi->protocol->callback,
1207                                                 wsi,
1208                                                 (enum lws_callback_reasons)callback_action,
1209                                                 wsi->user_space,
1210                                                 eff_buf.token,
1211                                                 eff_buf.token_len);
1212                         }
1213                         else
1214                                 lwsl_err("No callback on payload spill!\n");
1215                 }
1216
1217 already_done:
1218                 wsi->u.ws.rx_ubuf_head = 0;
1219                 break;
1220         }
1221
1222         return ret;
1223
1224 illegal_ctl_length:
1225
1226         lwsl_warn("Control frame with xtended length is illegal\n");
1227         /* kill the connection */
1228         return -1;
1229 }
1230
1231
1232 /**
1233  * lws_remaining_packet_payload() - Bytes to come before "overall"
1234  *                                            rx packet is complete
1235  * @wsi:                Websocket instance (available from user callback)
1236  *
1237  *      This function is intended to be called from the callback if the
1238  *  user code is interested in "complete packets" from the client.
1239  *  libwebsockets just passes through payload as it comes and issues a buffer
1240  *  additionally when it hits a built-in limit.  The LWS_CALLBACK_RECEIVE
1241  *  callback handler can use this API to find out if the buffer it has just
1242  *  been given is the last piece of a "complete packet" from the client --
1243  *  when that is the case lws_remaining_packet_payload() will return
1244  *  0.
1245  *
1246  *  Many protocols won't care becuse their packets are always small.
1247  */
1248
1249 LWS_VISIBLE size_t
1250 lws_remaining_packet_payload(struct lws *wsi)
1251 {
1252         return wsi->u.ws.rx_packet_length;
1253 }