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 LWS_VISIBLE int
 140 lws_hdr_fragment_length(struct lws *wsi, enum lws_token_indexes h, int frag_idx)
 141 {
 142         int n;
 143
 144         n = wsi->u.hdr.ah->frag_index[h];
 145         if (!n)
 146                 return 0;
 147         do {
 148                 if (!frag_idx)
 149                         return wsi->u.hdr.ah->frags[n].len;
 150                 n = wsi->u.hdr.ah->frags[n].nfrag;
 151         } while (frag_idx-- && n);
 152
 153         return 0;
 154 }
 155
 156 LWS_VISIBLE int lws_hdr_total_length(struct lws *wsi, enum lws_token_indexes h)
 157 {
 158         int n;
 159         int len = 0;
 160
 161         n = wsi->u.hdr.ah->frag_index[h];
 162         if (!n)
 163                 return 0;
 164         do {
 165                 len += wsi->u.hdr.ah->frags[n].len;
 166                 n = wsi->u.hdr.ah->frags[n].nfrag;
 167         } while (n);
 168
 169         return len;
 170 }
 171
 172 LWS_VISIBLE int lws_hdr_copy_fragment(struct lws *wsi, char *dst, int len,
 173                                       enum lws_token_indexes h, int frag_idx)
 174 {
 175         int n = 0;
 176         int f = wsi->u.hdr.ah->frag_index[h];
 177
 178         while (n < frag_idx) {
 179                 f = wsi->u.hdr.ah->frags[f].nfrag;
 180                 if (!f)
 181                         return -1;
 182                 n++;
 183         }
 184
 185         if (wsi->u.hdr.ah->frags[f].len >= len)
 186                 return -1;
 187
 188         memcpy(dst, wsi->u.hdr.ah->data + wsi->u.hdr.ah->frags[f].offset,
 189                wsi->u.hdr.ah->frags[f].len);
 190         dst[wsi->u.hdr.ah->frags[f].len] = '\0';
 191
 192         return wsi->u.hdr.ah->frags[f].len;
 193 }
 194
 195 LWS_VISIBLE int lws_hdr_copy(struct lws *wsi, char *dst, int len,
 196                              enum lws_token_indexes h)
 197 {
 198         int toklen = lws_hdr_total_length(wsi, h);
 199         int n;
 200
 201         if (toklen >= len)
 202                 return -1;
 203
 204         n = wsi->u.hdr.ah->frag_index[h];
 205         if (!n)
 206                 return 0;
 207
 208         do {
 209                 strcpy(dst, &wsi->u.hdr.ah->data[wsi->u.hdr.ah->frags[n].offset]);
 210                 dst += wsi->u.hdr.ah->frags[n].len;
 211                 n = wsi->u.hdr.ah->frags[n].nfrag;
 212         } while (n);
 213
 214         return toklen;
 215 }
 216
 217 char *lws_hdr_simple_ptr(struct lws *wsi, enum lws_token_indexes h)
 218 {
 219         int n;
 220
 221         n = wsi->u.hdr.ah->frag_index[h];
 222         if (!n)
 223                 return NULL;
 224
 225         return wsi->u.hdr.ah->data + wsi->u.hdr.ah->frags[n].offset;
 226 }
 227
 228 int lws_hdr_simple_create(struct lws *wsi, enum lws_token_indexes h,
 229                           const char *s)
 230 {
 231         wsi->u.hdr.ah->nfrag++;
 232         if (wsi->u.hdr.ah->nfrag == ARRAY_SIZE(wsi->u.hdr.ah->frags)) {
 233                 lwsl_warn("More hdr frags than we can deal with, dropping\n");
 234                 return -1;
 235         }
 236
 237         wsi->u.hdr.ah->frag_index[h] = wsi->u.hdr.ah->nfrag;
 238
 239         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].offset = wsi->u.hdr.ah->pos;
 240         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len = 0;
 241         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].nfrag = 0;
 242
 243         do {
 244                 if (wsi->u.hdr.ah->pos == wsi->context->max_http_header_data) {
 245                         lwsl_err("Ran out of header data space\n");
 246                         return -1;
 247                 }
 248                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = *s;
 249                 if (*s)
 250                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len++;
 251         } while (*s++);
 252
 253         return 0;
 254 }
 255
 256 static signed char char_to_hex(const char c)
 257 {
 258         if (c >= '0' && c <= '9')
 259                 return c - '0';
 260
 261         if (c >= 'a' && c <= 'f')
 262                 return c - 'a' + 10;
 263
 264         if (c >= 'A' && c <= 'F')
 265                 return c - 'A' + 10;
 266
 267         return -1;
 268 }
 269
 270 static int issue_char(struct lws *wsi, unsigned char c)
 271 {
 272         unsigned short frag_len;
 273
 274         if (wsi->u.hdr.ah->pos == wsi->context->max_http_header_data) {
 275                 lwsl_warn("excessive header content\n");
 276                 return -1;
 277         }
 278
 279         frag_len = wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len;
 280         /*
 281          * If we haven't hit the token limit, just copy the character into
 282          * the header
 283          */
 284         if (frag_len < wsi->u.hdr.current_token_limit) {
 285                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = c;
 286                 if (c)
 287                         wsi->u.hdr.ah->frags[wsi->u.hdr.ah->nfrag].len++;
 288                 return 0;
 289         }
 290
 291         /* Insert a null character when we *hit* the limit: */
 292         if (frag_len == wsi->u.hdr.current_token_limit) {
 293                 wsi->u.hdr.ah->data[wsi->u.hdr.ah->pos++] = '\0';
 294                 lwsl_warn("header %i exceeds limit %d\n",
 295                           wsi->u.hdr.parser_state, wsi->u.hdr.current_token_limit);
 296         }
 297
 298         return 1;
 299 }
 300
 301 int lws_parse(struct lws *wsi, unsigned char c)
 302 {
 303         static const unsigned char methods[] = {
 304                 WSI_TOKEN_GET_URI,
 305                 WSI_TOKEN_POST_URI,
 306                 WSI_TOKEN_OPTIONS_URI,
 307                 WSI_TOKEN_PUT_URI,
 308                 WSI_TOKEN_PATCH_URI,
 309                 WSI_TOKEN_DELETE_URI,
 310         };
 311         struct allocated_headers *ah = wsi->u.hdr.ah;
 312         struct lws_context *context = wsi->context;
 313         unsigned int n, m, enc = 0;
 314
 315         switch (wsi->u.hdr.parser_state) {
 316         default:
 317
 318                 lwsl_parser("WSI_TOK_(%d) '%c'\n", wsi->u.hdr.parser_state, c);
 319
 320                 /* collect into malloc'd buffers */
 321                 /* optional initial space swallow */
 322                 if (!ah->frags[ah->frag_index[
 323                                       wsi->u.hdr.parser_state]].len && c == ' ')
 324                         break;
 325
 326                 for (m = 0; m < ARRAY_SIZE(methods); m++)
 327                         if (wsi->u.hdr.parser_state == methods[m])
 328                                 break;
 329                 if (m == ARRAY_SIZE(methods))
 330                         /* it was not any of the methods */
 331                         goto check_eol;
 332
 333                 /* special URI processing... end at space */
 334
 335                 if (c == ' ') {
 336                         /* enforce starting with / */
 337                         if (!ah->frags[ah->nfrag].len)
 338                                 if (issue_char(wsi, '/') < 0)
 339                                         return -1;
 340
 341                         /* begin parsing HTTP version: */
 342                         if (issue_char(wsi, '\0') < 0)
 343                                 return -1;
 344                         wsi->u.hdr.parser_state = WSI_TOKEN_HTTP;
 345                         goto start_fragment;
 346                 }
 347
 348                 /* special URI processing... convert %xx */
 349
 350                 switch (wsi->u.hdr.ues) {
 351                 case URIES_IDLE:
 352                         if (c == '%') {
 353                                 wsi->u.hdr.ues = URIES_SEEN_PERCENT;
 354                                 goto swallow;
 355                         }
 356                         break;
 357                 case URIES_SEEN_PERCENT:
 358                         if (char_to_hex(c) < 0) {
 359                                 /* regurgitate */
 360                                 if (issue_char(wsi, '%') < 0)
 361                                         return -1;
 362                                 wsi->u.hdr.ues = URIES_IDLE;
 363                                 /* continue on to assess c */
 364                                 break;
 365                         }
 366                         wsi->u.hdr.esc_stash = c;
 367                         wsi->u.hdr.ues = URIES_SEEN_PERCENT_H1;
 368                         goto swallow;
 369
 370                 case URIES_SEEN_PERCENT_H1:
 371                         if (char_to_hex(c) < 0) {
 372                                 /* regurgitate */
 373                                 issue_char(wsi, '%');
 374                                 wsi->u.hdr.ues = URIES_IDLE;
 375                                 /* regurgitate + assess */
 376                                 if (lws_parse(wsi, wsi->u.hdr.esc_stash) < 0)
 377                                         return -1;
 378                                 /* continue on to assess c */
 379                                 break;
 380                         }
 381                         c = (char_to_hex(wsi->u.hdr.esc_stash) << 4) |
 382                                         char_to_hex(c);
 383                         enc = 1;
 384                         wsi->u.hdr.ues = URIES_IDLE;
 385                         break;
 386                 }
 387
 388                 /*
 389                  * special URI processing...
 390                  *  convert /.. or /... or /../ etc to /
 391                  *  convert /./ to /
 392                  *  convert // or /// etc to /
 393                  *  leave /.dir or whatever alone
 394                  */
 395
 396                 switch (wsi->u.hdr.ups) {
 397                 case URIPS_IDLE:
 398                         /* genuine delimiter */
 399                         if ((c == '&' || c == ';') && !enc) {
 400                                 issue_char(wsi, c);
 401                                 /* swallow the terminator */
 402                                 ah->frags[ah->nfrag].len--;
 403                                 /* link to next fragment */
 404                                 ah->frags[ah->nfrag].nfrag = ah->nfrag + 1;
 405                                 ah->nfrag++;
 406                                 if (ah->nfrag >= ARRAY_SIZE(ah->frags))
 407                                         goto excessive;
 408                                 /* start next fragment after the & */
 409                                 wsi->u.hdr.post_literal_equal = 0;
 410                                 ah->frags[ah->nfrag].offset = ah->pos;
 411                                 ah->frags[ah->nfrag].len = 0;
 412                                 ah->frags[ah->nfrag].nfrag = 0;
 413                                 goto swallow;
 414                         }
 415                         /* uriencoded = in the name part, disallow */
 416                         if (c == '=' && enc && !wsi->u.hdr.post_literal_equal)
 417                                 c = '_';
 418
 419                         /* after the real =, we don't care how many = */
 420                         if (c == '=' && !enc)
 421                                 wsi->u.hdr.post_literal_equal = 1;
 422
 423                         /* + to space */
 424                         if (c == '+' && !enc)
 425                                 c = ' ';
 426                         /* issue the first / always */
 427                         if (c == '/' && !ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS])
 428                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 429                         break;
 430                 case URIPS_SEEN_SLASH:
 431                         /* swallow subsequent slashes */
 432                         if (c == '/')
 433                                 goto swallow;
 434                         /* track and swallow the first . after / */
 435                         if (c == '.') {
 436                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT;
 437                                 goto swallow;
 438                         }
 439                         wsi->u.hdr.ups = URIPS_IDLE;
 440                         break;
 441                 case URIPS_SEEN_SLASH_DOT:
 442                         /* swallow second . */
 443                         if (c == '.') {
 444                                 /*
 445                                  * back up one dir level if possible
 446                                  * safe against header fragmentation because
 447                                  * the method URI can only be in 1 fragment
 448                                  */
 449                                 if (ah->frags[ah->nfrag].len > 2) {
 450                                         ah->pos--;
 451                                         ah->frags[ah->nfrag].len--;
 452                                         do {
 453                                                 ah->pos--;
 454                                                 ah->frags[ah->nfrag].len--;
 455                                         } while (ah->frags[ah->nfrag].len > 1 &&
 456                                                  ah->data[ah->pos] != '/');
 457                                 }
 458                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH_DOT_DOT;
 459                                 goto swallow;
 460                         }
 461                         /* change /./ to / */
 462                         if (c == '/') {
 463                                 wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 464                                 goto swallow;
 465                         }
 466                         /* it was like /.dir ... regurgitate the . */
 467                         wsi->u.hdr.ups = URIPS_IDLE;
 468                         if (issue_char(wsi, '.') < 0)
 469                                 return -1;
 470                         break;
 471
 472                 case URIPS_SEEN_SLASH_DOT_DOT:
 473                         /* swallow prior .. chars and any subsequent . */
 474                         if (c == '.')
 475                                 goto swallow;
 476                         /* last issued was /, so another / == // */
 477                         if (c == '/')
 478                                 goto swallow;
 479                         /* last we issued was / so SEEN_SLASH */
 480                         wsi->u.hdr.ups = URIPS_SEEN_SLASH;
 481                         break;
 482                 }
 483
 484                 if (c == '?' && !enc &&
 485                     !ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS]) { /* start of URI arguments */
 486                         /* seal off uri header */
 487                         ah->data[ah->pos++] = '\0';
 488
 489                         /* move to using WSI_TOKEN_HTTP_URI_ARGS */
 490                         ah->nfrag++;
 491                         if (ah->nfrag >= ARRAY_SIZE(ah->frags))
 492                                 goto excessive;
 493                         ah->frags[ah->nfrag].offset = ah->pos;
 494                         ah->frags[ah->nfrag].len = 0;
 495                         ah->frags[ah->nfrag].nfrag = 0;
 496
 497                         wsi->u.hdr.post_literal_equal = 0;
 498                         ah->frag_index[WSI_TOKEN_HTTP_URI_ARGS] = ah->nfrag;
 499                         wsi->u.hdr.ups = URIPS_IDLE;
 500                         goto swallow;
 501                 }
 502
 503 check_eol:
 504
 505                 /* bail at EOL */
 506                 if (wsi->u.hdr.parser_state != WSI_TOKEN_CHALLENGE &&
 507                                                                   c == '\x0d') {
 508                         c = '\0';
 509                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 510                         lwsl_parser("*\n");
 511                 }
 512
 513                 n = issue_char(wsi, c);
 514                 if ((int)n < 0)
 515                         return -1;
 516                 if (n > 0)
 517                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 518
 519 swallow:
 520                 /* per-protocol end of headers management */
 521
 522                 if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 523                         goto set_parsing_complete;
 524                 break;
 525
 526                 /* collecting and checking a name part */
 527         case WSI_TOKEN_NAME_PART:
 528                 lwsl_parser("WSI_TOKEN_NAME_PART '%c' (mode=%d)\n", c, wsi->mode);
 529
 530                 wsi->u.hdr.lextable_pos =
 531                                 lextable_decode(wsi->u.hdr.lextable_pos, c);
 532                 /*
 533                  * Server needs to look out for unknown methods...
 534                  */
 535                 if (wsi->u.hdr.lextable_pos < 0 &&
 536                     wsi->mode == LWSCM_HTTP_SERVING) {
 537                         /* this is not a header we know about */
 538                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 539                                 if (ah->frag_index[methods[m]]) {
 540                                         /*
 541                                          * already had the method, no idea what
 542                                          * this crap from the client is, ignore
 543                                          */
 544                                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 545                                         break;
 546                                 }
 547                         /*
 548                          * hm it's an unknown http method from a client in fact,
 549                          * treat as dangerous
 550                          */
 551                         if (m == ARRAY_SIZE(methods)) {
 552                                 lwsl_info("Unknown method - dropping\n");
 553                                 return -1;
 554                         }
 555                         break;
 556                 }
 557                 /*
 558                  * ...otherwise for a client, let him ignore unknown headers
 559                  * coming from the server
 560                  */
 561                 if (wsi->u.hdr.lextable_pos < 0) {
 562                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 563                         break;
 564                 }
 565
 566                 if (lextable[wsi->u.hdr.lextable_pos] < FAIL_CHAR) {
 567                         /* terminal state */
 568
 569                         n = ((unsigned int)lextable[wsi->u.hdr.lextable_pos] << 8) |
 570                                         lextable[wsi->u.hdr.lextable_pos + 1];
 571
 572                         lwsl_parser("known hdr %d\n", n);
 573                         for (m = 0; m < ARRAY_SIZE(methods); m++)
 574                                 if (n == methods[m] &&
 575                                                 ah->frag_index[
 576                                                         methods[m]]) {
 577                                         lwsl_warn("Duplicated method\n");
 578                                         return -1;
 579                                 }
 580
 581                         /*
 582                          * WSORIGIN is protocol equiv to ORIGIN,
 583                          * JWebSocket likes to send it, map to ORIGIN
 584                          */
 585                         if (n == WSI_TOKEN_SWORIGIN)
 586                                 n = WSI_TOKEN_ORIGIN;
 587
 588                         wsi->u.hdr.parser_state = (enum lws_token_indexes)
 589                                                         (WSI_TOKEN_GET_URI + n);
 590
 591                         if (context->token_limits)
 592                                 wsi->u.hdr.current_token_limit =
 593                                         context->token_limits->token_limit[
 594                                                        wsi->u.hdr.parser_state];
 595                         else
 596                                 wsi->u.hdr.current_token_limit =
 597                                         wsi->context->max_http_header_data;
 598
 599                         if (wsi->u.hdr.parser_state == WSI_TOKEN_CHALLENGE)
 600                                 goto set_parsing_complete;
 601
 602                         goto start_fragment;
 603                 }
 604                 break;
 605
 606 start_fragment:
 607                 ah->nfrag++;
 608 excessive:
 609                 if (ah->nfrag == ARRAY_SIZE(ah->frags)) {
 610                         lwsl_warn("More hdr frags than we can deal with\n");
 611                         return -1;
 612                 }
 613
 614                 ah->frags[ah->nfrag].offset = ah->pos;
 615                 ah->frags[ah->nfrag].len = 0;
 616                 ah->frags[ ah->nfrag].nfrag = 0;
 617
 618                 n = ah->frag_index[wsi->u.hdr.parser_state];
 619                 if (!n) { /* first fragment */
 620                         ah->frag_index[wsi->u.hdr.parser_state] = ah->nfrag;
 621                         break;
 622                 }
 623                 /* continuation */
 624                 while (ah->frags[n].nfrag)
 625                                 n = ah->frags[n].nfrag;
 626                 ah->frags[n].nfrag = ah->nfrag;
 627
 628                 if (ah->pos == wsi->context->max_http_header_data) {
 629                         lwsl_warn("excessive header content\n");
 630                         return -1;
 631                 }
 632
 633                 ah->data[ah->pos++] = ' ';
 634                 ah->frags[ah->nfrag].len++;
 635                 break;
 636
 637                 /* skipping arg part of a name we didn't recognize */
 638         case WSI_TOKEN_SKIPPING:
 639                 lwsl_parser("WSI_TOKEN_SKIPPING '%c'\n", c);
 640
 641                 if (c == '\x0d')
 642                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING_SAW_CR;
 643                 break;
 644
 645         case WSI_TOKEN_SKIPPING_SAW_CR:
 646                 lwsl_parser("WSI_TOKEN_SKIPPING_SAW_CR '%c'\n", c);
 647                 if (c == '\x0a') {
 648                         wsi->u.hdr.parser_state = WSI_TOKEN_NAME_PART;
 649                         wsi->u.hdr.lextable_pos = 0;
 650                 } else
 651                         wsi->u.hdr.parser_state = WSI_TOKEN_SKIPPING;
 652                 break;
 653                 /* we're done, ignore anything else */
 654
 655         case WSI_PARSING_COMPLETE:
 656                 lwsl_parser("WSI_PARSING_COMPLETE '%c'\n", c);
 657                 break;
 658         }
 659
 660         return 0;
 661
 662 set_parsing_complete:
 663
 664         if (lws_hdr_total_length(wsi, WSI_TOKEN_UPGRADE)) {
 665                 if (lws_hdr_total_length(wsi, WSI_TOKEN_VERSION))
 666                         wsi->ietf_spec_revision =
 667                                atoi(lws_hdr_simple_ptr(wsi, WSI_TOKEN_VERSION));
 668
 669                 lwsl_parser("v%02d hdrs completed\n", wsi->ietf_spec_revision);
 670         }
 671         wsi->u.hdr.parser_state = WSI_PARSING_COMPLETE;
 672         wsi->hdr_parsing_completed = 1;
 673
 674         return 0;
 675 }
 676
 677
 678 /**
 679  * lws_frame_is_binary: true if the current frame was sent in binary mode
 680  *
 681  * @wsi: the connection we are inquiring about
 682  *
 683  * This is intended to be called from the LWS_CALLBACK_RECEIVE callback if
 684  * it's interested to see if the frame it's dealing with was sent in binary
 685  * mode.
 686  */
 687
 688 LWS_VISIBLE int lws_frame_is_binary(struct lws *wsi)
 689 {
 690         return wsi->u.ws.frame_is_binary;
 691 }
 692
 693 int
 694 lws_rx_sm(struct lws *wsi, unsigned char c)
 695 {
 696         struct lws_tokens eff_buf;
 697         int ret = 0;
 698         int callback_action = LWS_CALLBACK_RECEIVE;
 699
 700         switch (wsi->lws_rx_parse_state) {
 701         case LWS_RXPS_NEW:
 702
 703                 switch (wsi->ietf_spec_revision) {
 704                 case 13:
 705                         /*
 706                          * no prepended frame key any more
 707                          */
 708                         wsi->u.ws.all_zero_nonce = 1;
 709                         goto handle_first;
 710
 711                 default:
 712                         lwsl_warn("lws_rx_sm: unknown spec version %d\n",
 713                                                        wsi->ietf_spec_revision);
 714                         break;
 715                 }
 716                 break;
 717         case LWS_RXPS_04_MASK_NONCE_1:
 718                 wsi->u.ws.mask_nonce[1] = c;
 719                 if (c)
 720                         wsi->u.ws.all_zero_nonce = 0;
 721                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_2;
 722                 break;
 723         case LWS_RXPS_04_MASK_NONCE_2:
 724                 wsi->u.ws.mask_nonce[2] = c;
 725                 if (c)
 726                         wsi->u.ws.all_zero_nonce = 0;
 727                 wsi->lws_rx_parse_state = LWS_RXPS_04_MASK_NONCE_3;
 728                 break;
 729         case LWS_RXPS_04_MASK_NONCE_3:
 730                 wsi->u.ws.mask_nonce[3] = c;
 731                 if (c)
 732                         wsi->u.ws.all_zero_nonce = 0;
 733
 734                 /*
 735                  * start from the zero'th byte in the XOR key buffer since
 736                  * this is the start of a frame with a new key
 737                  */
 738
 739                 wsi->u.ws.frame_mask_index = 0;
 740
 741                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_1;
 742                 break;
 743
 744         /*
 745          *  04 logical framing from the spec (all this is masked when incoming
 746          *  and has to be unmasked)
 747          *
 748          * We ignore the possibility of extension data because we don't
 749          * negotiate any extensions at the moment.
 750          *
 751          *    0                   1                   2                   3
 752          *    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
 753          *   +-+-+-+-+-------+-+-------------+-------------------------------+
 754          *   |F|R|R|R| opcode|R| Payload len |    Extended payload length    |
 755          *   |I|S|S|S|  (4)  |S|     (7)     |             (16/63)           |
 756          *   |N|V|V|V|       |V|             |   (if payload len==126/127)   |
 757          *   | |1|2|3|       |4|             |                               |
 758          *   +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 759          *   |     Extended payload length continued, if payload len == 127  |
 760          *   + - - - - - - - - - - - - - - - +-------------------------------+
 761          *   |                               |         Extension data        |
 762          *   +-------------------------------+ - - - - - - - - - - - - - - - +
 763          *   :                                                               :
 764          *   +---------------------------------------------------------------+
 765          *   :                       Application data                        :
 766          *   +---------------------------------------------------------------+
 767          *
 768          *  We pass payload through to userland as soon as we get it, ignoring
 769          *  FIN.  It's up to userland to buffer it up if it wants to see a
 770          *  whole unfragmented block of the original size (which may be up to
 771          *  2^63 long!)
 772          */
 773
 774         case LWS_RXPS_04_FRAME_HDR_1:
 775 handle_first:
 776
 777                 wsi->u.ws.opcode = c & 0xf;
 778                 wsi->u.ws.rsv = c & 0x70;
 779                 wsi->u.ws.final = !!((c >> 7) & 1);
 780
 781                 switch (wsi->u.ws.opcode) {
 782                 case LWSWSOPC_TEXT_FRAME:
 783                 case LWSWSOPC_BINARY_FRAME:
 784                         wsi->u.ws.frame_is_binary =
 785                              wsi->u.ws.opcode == LWSWSOPC_BINARY_FRAME;
 786                         break;
 787                 }
 788                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN;
 789                 break;
 790
 791         case LWS_RXPS_04_FRAME_HDR_LEN:
 792
 793                 wsi->u.ws.this_frame_masked = !!(c & 0x80);
 794
 795                 switch (c & 0x7f) {
 796                 case 126:
 797                         /* control frames are not allowed to have big lengths */
 798                         if (wsi->u.ws.opcode & 8)
 799                                 goto illegal_ctl_length;
 800
 801                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_2;
 802                         break;
 803                 case 127:
 804                         /* control frames are not allowed to have big lengths */
 805                         if (wsi->u.ws.opcode & 8)
 806                                 goto illegal_ctl_length;
 807
 808                         wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_8;
 809                         break;
 810                 default:
 811                         wsi->u.ws.rx_packet_length = c & 0x7f;
 812                         if (wsi->u.ws.this_frame_masked)
 813                                 wsi->lws_rx_parse_state =
 814                                                 LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 815                         else
 816                                 if (wsi->u.ws.rx_packet_length)
 817                                         wsi->lws_rx_parse_state =
 818                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 819                                 else {
 820                                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 821                                         goto spill;
 822                                 }
 823                         break;
 824                 }
 825                 break;
 826
 827         case LWS_RXPS_04_FRAME_HDR_LEN16_2:
 828                 wsi->u.ws.rx_packet_length = c << 8;
 829                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN16_1;
 830                 break;
 831
 832         case LWS_RXPS_04_FRAME_HDR_LEN16_1:
 833                 wsi->u.ws.rx_packet_length |= c;
 834                 if (wsi->u.ws.this_frame_masked)
 835                         wsi->lws_rx_parse_state =
 836                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 837                 else
 838                         wsi->lws_rx_parse_state =
 839                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 840                 break;
 841
 842         case LWS_RXPS_04_FRAME_HDR_LEN64_8:
 843                 if (c & 0x80) {
 844                         lwsl_warn("b63 of length must be zero\n");
 845                         /* kill the connection */
 846                         return -1;
 847                 }
 848 #if defined __LP64__
 849                 wsi->u.ws.rx_packet_length = ((size_t)c) << 56;
 850 #else
 851                 wsi->u.ws.rx_packet_length = 0;
 852 #endif
 853                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_7;
 854                 break;
 855
 856         case LWS_RXPS_04_FRAME_HDR_LEN64_7:
 857 #if defined __LP64__
 858                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 48;
 859 #endif
 860                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_6;
 861                 break;
 862
 863         case LWS_RXPS_04_FRAME_HDR_LEN64_6:
 864 #if defined __LP64__
 865                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 40;
 866 #endif
 867                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_5;
 868                 break;
 869
 870         case LWS_RXPS_04_FRAME_HDR_LEN64_5:
 871 #if defined __LP64__
 872                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 32;
 873 #endif
 874                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_4;
 875                 break;
 876
 877         case LWS_RXPS_04_FRAME_HDR_LEN64_4:
 878                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 24;
 879                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_3;
 880                 break;
 881
 882         case LWS_RXPS_04_FRAME_HDR_LEN64_3:
 883                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 16;
 884                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_2;
 885                 break;
 886
 887         case LWS_RXPS_04_FRAME_HDR_LEN64_2:
 888                 wsi->u.ws.rx_packet_length |= ((size_t)c) << 8;
 889                 wsi->lws_rx_parse_state = LWS_RXPS_04_FRAME_HDR_LEN64_1;
 890                 break;
 891
 892         case LWS_RXPS_04_FRAME_HDR_LEN64_1:
 893                 wsi->u.ws.rx_packet_length |= ((size_t)c);
 894                 if (wsi->u.ws.this_frame_masked)
 895                         wsi->lws_rx_parse_state =
 896                                         LWS_RXPS_07_COLLECT_FRAME_KEY_1;
 897                 else
 898                         wsi->lws_rx_parse_state =
 899                                 LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 900                 break;
 901
 902         case LWS_RXPS_07_COLLECT_FRAME_KEY_1:
 903                 wsi->u.ws.mask_nonce[0] = c;
 904                 if (c)
 905                         wsi->u.ws.all_zero_nonce = 0;
 906                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_2;
 907                 break;
 908
 909         case LWS_RXPS_07_COLLECT_FRAME_KEY_2:
 910                 wsi->u.ws.mask_nonce[1] = c;
 911                 if (c)
 912                         wsi->u.ws.all_zero_nonce = 0;
 913                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_3;
 914                 break;
 915
 916         case LWS_RXPS_07_COLLECT_FRAME_KEY_3:
 917                 wsi->u.ws.mask_nonce[2] = c;
 918                 if (c)
 919                         wsi->u.ws.all_zero_nonce = 0;
 920                 wsi->lws_rx_parse_state = LWS_RXPS_07_COLLECT_FRAME_KEY_4;
 921                 break;
 922
 923         case LWS_RXPS_07_COLLECT_FRAME_KEY_4:
 924                 wsi->u.ws.mask_nonce[3] = c;
 925                 if (c)
 926                         wsi->u.ws.all_zero_nonce = 0;
 927                 wsi->lws_rx_parse_state =
 928                                         LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED;
 929                 wsi->u.ws.frame_mask_index = 0;
 930                 if (wsi->u.ws.rx_packet_length == 0) {
 931                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 932                         goto spill;
 933                 }
 934                 break;
 935
 936
 937         case LWS_RXPS_PAYLOAD_UNTIL_LENGTH_EXHAUSTED:
 938
 939                 if (!wsi->u.ws.rx_user_buffer) {
 940                         lwsl_err("NULL user buffer...\n");
 941                         return 1;
 942                 }
 943
 944                 if (wsi->u.ws.all_zero_nonce)
 945                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 946                                (wsi->u.ws.rx_user_buffer_head++)] = c;
 947                 else
 948                         wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING +
 949                                (wsi->u.ws.rx_user_buffer_head++)] =
 950                                    c ^ wsi->u.ws.mask_nonce[
 951                                             (wsi->u.ws.frame_mask_index++) & 3];
 952
 953                 if (--wsi->u.ws.rx_packet_length == 0) {
 954                         /* spill because we have the whole frame */
 955                         wsi->lws_rx_parse_state = LWS_RXPS_NEW;
 956                         goto spill;
 957                 }
 958
 959                 /*
 960                  * if there's no protocol max frame size given, we are
 961                  * supposed to default to LWS_MAX_SOCKET_IO_BUF
 962                  */
 963
 964                 if (!wsi->protocol->rx_buffer_size &&
 965                                         wsi->u.ws.rx_user_buffer_head !=
 966                                                           LWS_MAX_SOCKET_IO_BUF)
 967                         break;
 968                 else
 969                         if (wsi->protocol->rx_buffer_size &&
 970                                         wsi->u.ws.rx_user_buffer_head !=
 971                                                   wsi->protocol->rx_buffer_size)
 972                         break;
 973
 974                 /* spill because we filled our rx buffer */
 975 spill:
 976                 /*
 977                  * is this frame a control packet we should take care of at this
 978                  * layer?  If so service it and hide it from the user callback
 979                  */
 980
 981                 lwsl_parser("spill on %s\n", wsi->protocol->name);
 982
 983                 switch (wsi->u.ws.opcode) {
 984                 case LWSWSOPC_CLOSE:
 985
 986                         /* is this an acknowledgement of our close? */
 987                         if (wsi->state == LWSS_AWAITING_CLOSE_ACK) {
 988                                 /*
 989                                  * fine he has told us he is closing too, let's
 990                                  * finish our close
 991                                  */
 992                                 lwsl_parser("seen client close ack\n");
 993                                 return -1;
 994                         }
 995                         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
 996                                 /* if he sends us 2 CLOSE, kill him */
 997                                 return -1;
 998
 999                         if (user_callback_handle_rxflow(
1000                                         wsi->protocol->callback, wsi,
1001                                         LWS_CALLBACK_WS_PEER_INITIATED_CLOSE,
1002                                         wsi->user_space,
1003                                         &wsi->u.ws.rx_user_buffer[
1004                                                 LWS_SEND_BUFFER_PRE_PADDING],
1005                                         wsi->u.ws.rx_user_buffer_head))
1006                                 return -1;
1007
1008                         lwsl_parser("server sees client close packet\n");
1009                         wsi->state = LWSS_RETURNED_CLOSE_ALREADY;
1010                         /* deal with the close packet contents as a PONG */
1011                         wsi->u.ws.payload_is_close = 1;
1012                         goto process_as_ping;
1013
1014                 case LWSWSOPC_PING:
1015                         lwsl_info("received %d byte ping, sending pong\n",
1016                                                  wsi->u.ws.rx_user_buffer_head);
1017
1018                         if (wsi->u.ws.ping_pending_flag) {
1019                                 /*
1020                                  * there is already a pending ping payload
1021                                  * we should just log and drop
1022                                  */
1023                                 lwsl_parser("DROP PING since one pending\n");
1024                                 goto ping_drop;
1025                         }
1026 process_as_ping:
1027                         /* control packets can only be < 128 bytes long */
1028                         if (wsi->u.ws.rx_user_buffer_head > 128 - 4) {
1029                                 lwsl_parser("DROP PING payload too large\n");
1030                                 goto ping_drop;
1031                         }
1032
1033                         /* stash the pong payload */
1034                         memcpy(wsi->u.ws.ping_payload_buf + LWS_SEND_BUFFER_PRE_PADDING,
1035                                &wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
1036                                 wsi->u.ws.rx_user_buffer_head);
1037
1038                         wsi->u.ws.ping_payload_len = wsi->u.ws.rx_user_buffer_head;
1039                         wsi->u.ws.ping_pending_flag = 1;
1040
1041                         /* get it sent as soon as possible */
1042                         lws_callback_on_writable(wsi);
1043 ping_drop:
1044                         wsi->u.ws.rx_user_buffer_head = 0;
1045                         return 0;
1046
1047                 case LWSWSOPC_PONG:
1048                         lwsl_info("received pong\n");
1049                         lwsl_hexdump(&wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
1050                                      wsi->u.ws.rx_user_buffer_head);
1051
1052                         /* issue it */
1053                         callback_action = LWS_CALLBACK_RECEIVE_PONG;
1054                         break;
1055
1056                 case LWSWSOPC_TEXT_FRAME:
1057                 case LWSWSOPC_BINARY_FRAME:
1058                 case LWSWSOPC_CONTINUATION:
1059                         break;
1060
1061                 default:
1062                         lwsl_parser("passing opc %x up to exts\n",
1063                                                         wsi->u.ws.opcode);
1064                         /*
1065                          * It's something special we can't understand here.
1066                          * Pass the payload up to the extension's parsing
1067                          * state machine.
1068                          */
1069
1070                         eff_buf.token = &wsi->u.ws.rx_user_buffer[
1071                                                    LWS_SEND_BUFFER_PRE_PADDING];
1072                         eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
1073
1074                         if (lws_ext_cb_wsi_active_exts(wsi,
1075                                 LWS_EXT_CALLBACK_EXTENDED_PAYLOAD_RX,
1076                                         &eff_buf, 0) <= 0) /* not handle or fail */
1077                                 lwsl_ext("ext opc opcode 0x%x unknown\n",
1078                                                               wsi->u.ws.opcode);
1079
1080                         wsi->u.ws.rx_user_buffer_head = 0;
1081                         return 0;
1082                 }
1083
1084                 /*
1085                  * No it's real payload, pass it up to the user callback.
1086                  * It's nicely buffered with the pre-padding taken care of
1087                  * so it can be sent straight out again using lws_write
1088                  */
1089
1090                 eff_buf.token = &wsi->u.ws.rx_user_buffer[
1091                                                 LWS_SEND_BUFFER_PRE_PADDING];
1092                 eff_buf.token_len = wsi->u.ws.rx_user_buffer_head;
1093
1094                 if (lws_ext_cb_wsi_active_exts(wsi,
1095                                 LWS_EXT_CALLBACK_PAYLOAD_RX, &eff_buf, 0) < 0)
1096                         return -1;
1097
1098                 if (eff_buf.token_len > 0 ||
1099                     callback_action == LWS_CALLBACK_RECEIVE_PONG) {
1100                         eff_buf.token[eff_buf.token_len] = '\0';
1101
1102                         if (wsi->protocol->callback) {
1103
1104                                 if (callback_action == LWS_CALLBACK_RECEIVE_PONG)
1105                                     lwsl_info("Doing pong callback\n");
1106
1107                                 ret = user_callback_handle_rxflow(
1108                                                 wsi->protocol->callback,
1109                                                 wsi,
1110                                                 (enum lws_callback_reasons)callback_action,
1111                                                 wsi->user_space,
1112                                                 eff_buf.token,
1113                                                 eff_buf.token_len);
1114                         }
1115                         else
1116                                 lwsl_err("No callback on payload spill!\n");
1117                 }
1118
1119                 wsi->u.ws.rx_user_buffer_head = 0;
1120                 break;
1121         }
1122
1123         return ret;
1124
1125 illegal_ctl_length:
1126
1127         lwsl_warn("Control frame with xtended length is illegal\n");
1128         /* kill the connection */
1129         return -1;
1130 }
1131
1132
1133 /**
1134  * lws_remaining_packet_payload() - Bytes to come before "overall"
1135  *                                            rx packet is complete
1136  * @wsi:                Websocket instance (available from user callback)
1137  *
1138  *      This function is intended to be called from the callback if the
1139  *  user code is interested in "complete packets" from the client.
1140  *  libwebsockets just passes through payload as it comes and issues a buffer
1141  *  additionally when it hits a built-in limit.  The LWS_CALLBACK_RECEIVE
1142  *  callback handler can use this API to find out if the buffer it has just
1143  *  been given is the last piece of a "complete packet" from the client --
1144  *  when that is the case lws_remaining_packet_payload() will return
1145  *  0.
1146  *
1147  *  Many protocols won't care becuse their packets are always small.
1148  */
1149
1150 LWS_VISIBLE size_t
1151 lws_remaining_packet_payload(struct lws *wsi)
1152 {
1153         return wsi->u.ws.rx_packet_length;
1154 }