src/websock.c

   1 /*
   2  * Copyright (C) 2016, 2017 "IoT.bzh"
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 /*
  18  * This work is a far adaptation of apache-websocket:
  19  *   origin:  https://github.com/disconnect/apache-websocket
  20  *   commit:  cfaef071223f11ba016bff7e1e4b7c9e5df45b50
  21  *   Copyright 2010-2012 self.disconnect (APACHE-2)
  22  */
  23
  24 #include <stdlib.h>
  25 #include <stdint.h>
  26 #include <errno.h>
  27 #include <string.h>
  28 #include <sys/uio.h>
  29
  30 #include "websock.h"
  31
  32 #define BLOCK_DATA_SIZE              4096
  33 #if !defined(WEBSOCKET_DEFAULT_MAXLENGTH)
  34 #  define WEBSOCKET_DEFAULT_MAXLENGTH 1048500  /* 76 less than 1M, probably enougth for headers */
  35 #endif
  36
  37 #define FRAME_GET_FIN(BYTE)         (((BYTE) >> 7) & 0x01)
  38 #define FRAME_GET_RSV1(BYTE)        (((BYTE) >> 6) & 0x01)
  39 #define FRAME_GET_RSV2(BYTE)        (((BYTE) >> 5) & 0x01)
  40 #define FRAME_GET_RSV3(BYTE)        (((BYTE) >> 4) & 0x01)
  41 #define FRAME_GET_OPCODE(BYTE)      ( (BYTE)       & 0x0F)
  42 #define FRAME_GET_MASK(BYTE)        (((BYTE) >> 7) & 0x01)
  43 #define FRAME_GET_PAYLOAD_LEN(BYTE) ( (BYTE)       & 0x7F)
  44
  45 #define FRAME_SET_FIN(BYTE)         (((BYTE) & 0x01) << 7)
  46 #define FRAME_SET_RSV1(BYTE)        (((BYTE) & 0x01) << 6)
  47 #define FRAME_SET_RSV2(BYTE)        (((BYTE) & 0x01) << 5)
  48 #define FRAME_SET_RSV3(BYTE)        (((BYTE) & 0x01) << 4)
  49 #define FRAME_SET_OPCODE(BYTE)      ((BYTE) & 0x0F)
  50 #define FRAME_SET_MASK(BYTE)        (((BYTE) & 0x01) << 7)
  51 #define FRAME_SET_LENGTH(X64, IDX)  (unsigned char)((sizeof(X64)) <= (IDX) ? 0 : (((X64) >> ((IDX)*8)) & 0xFF))
  52
  53 #define OPCODE_CONTINUATION 0x0
  54 #define OPCODE_TEXT         0x1
  55 #define OPCODE_BINARY       0x2
  56 #define OPCODE_CLOSE        0x8
  57 #define OPCODE_PING         0x9
  58 #define OPCODE_PONG         0xA
  59
  60 #define STATE_INIT    0
  61 #define STATE_START   1
  62 #define STATE_LENGTH  2
  63 #define STATE_DATA    3
  64
  65 static size_t default_maxlength = WEBSOCKET_DEFAULT_MAXLENGTH;
  66
  67 struct websock {
  68         int state;
  69         uint64_t maxlength;
  70         int lenhead, szhead;
  71         uint64_t length;
  72         uint32_t mask;
  73         unsigned char header[14];       /* 2 + 8 + 4 */
  74         const struct websock_itf *itf;
  75         void *closure;
  76 };
  77
  78 static ssize_t ws_writev(struct websock *ws, const struct iovec *iov, int iovcnt)
  79 {
  80         return ws->itf->writev(ws->closure, iov, iovcnt);
  81 }
  82
  83 static ssize_t ws_readv(struct websock *ws, const struct iovec *iov, int iovcnt)
  84 {
  85         return ws->itf->readv(ws->closure, iov, iovcnt);
  86 }
  87
  88 #if 0
  89 static ssize_t ws_write(struct websock *ws, const void *buffer, size_t buffer_size)
  90 {
  91         struct iovec iov;
  92         iov.iov_base = (void *)buffer;  /* const cast */
  93         iov.iov_len = buffer_size;
  94         return ws_writev(ws, &iov, 1);
  95 }
  96 #endif
  97
  98 static ssize_t ws_read(struct websock *ws, void *buffer, size_t buffer_size)
  99 {
 100         struct iovec iov;
 101         iov.iov_base = buffer;
 102         iov.iov_len = buffer_size;
 103         return ws_readv(ws, &iov, 1);
 104 }
 105
 106 static int websock_send_internal_v(struct websock *ws, unsigned char first, const struct iovec *iovec, int count)
 107 {
 108         struct iovec iov[32];
 109         int i, j;
 110         size_t pos, size, len;
 111         ssize_t rc;
 112         unsigned char header[32];
 113
 114         /* checks count */
 115         if (count < 0 || (count + 1) > (int)(sizeof iov / sizeof * iov)) {
 116                 errno = EINVAL;
 117                 return -1;
 118         }
 119
 120         /* computes the size */
 121         size = 0;
 122         i = 1;
 123         for (j = 0 ; j < count ; j++) {
 124                 iov[i].iov_base = iovec[j].iov_base;
 125                 len = iovec[j].iov_len;
 126                 if (len != 0) {
 127                         iov[i].iov_len = len;
 128                         size += len;
 129                         i++;
 130                 }
 131         }
 132
 133         /* makes the header */
 134         pos = 0;
 135         header[pos++] = first;
 136         size = (uint64_t) size;
 137         if (size < 126) {
 138                 header[pos++] = FRAME_SET_MASK(0) | FRAME_SET_LENGTH(size, 0);
 139         } else {
 140                 if (size < 65536) {
 141                         header[pos++] = FRAME_SET_MASK(0) | 126;
 142                 } else {
 143                         header[pos++] = FRAME_SET_MASK(0) | 127;
 144                         header[pos++] = FRAME_SET_LENGTH(size, 7);
 145                         header[pos++] = FRAME_SET_LENGTH(size, 6);
 146                         header[pos++] = FRAME_SET_LENGTH(size, 5);
 147                         header[pos++] = FRAME_SET_LENGTH(size, 4);
 148                         header[pos++] = FRAME_SET_LENGTH(size, 3);
 149                         header[pos++] = FRAME_SET_LENGTH(size, 2);
 150                 }
 151                 header[pos++] = FRAME_SET_LENGTH(size, 1);
 152                 header[pos++] = FRAME_SET_LENGTH(size, 0);
 153         }
 154
 155         /* allocates the vec */
 156         iov[0].iov_base = header;
 157         iov[0].iov_len = pos;
 158         rc = ws_writev(ws, iov, i);
 159
 160         return rc < 0 ? -1 : 0;
 161 }
 162
 163 static int websock_send_internal(struct websock *ws, unsigned char first, const void *buffer, size_t size)
 164 {
 165         struct iovec iov;
 166
 167         iov.iov_base = (void *)buffer;
 168         iov.iov_len = size;
 169         return websock_send_internal_v(ws, first, &iov, 1);
 170 }
 171
 172 static inline int websock_send_v(struct websock *ws, int last, int rsv1, int rsv2, int rsv3, int opcode, const struct iovec *iovec, int count)
 173 {
 174         unsigned char first = (unsigned char)(FRAME_SET_FIN(last)
 175                                 | FRAME_SET_RSV1(rsv1)
 176                                 | FRAME_SET_RSV1(rsv2)
 177                                 | FRAME_SET_RSV1(rsv3)
 178                                 | FRAME_SET_OPCODE(opcode));
 179         return websock_send_internal_v(ws, first, iovec, count);
 180 }
 181
 182 static inline int websock_send(struct websock *ws, int last, int rsv1, int rsv2, int rsv3, int opcode, const void *buffer, size_t size)
 183 {
 184         unsigned char first = (unsigned char)(FRAME_SET_FIN(last)
 185                                 | FRAME_SET_RSV1(rsv1)
 186                                 | FRAME_SET_RSV1(rsv2)
 187                                 | FRAME_SET_RSV1(rsv3)
 188                                 | FRAME_SET_OPCODE(opcode));
 189         return websock_send_internal(ws, first, buffer, size);
 190 }
 191
 192 int websock_close_empty(struct websock *ws)
 193 {
 194         return websock_close(ws, WEBSOCKET_CODE_NOT_SET, NULL, 0);
 195 }
 196
 197 int websock_close(struct websock *ws, uint16_t code, const void *data, size_t length)
 198 {
 199         unsigned char buffer[2];
 200         struct iovec iov[2];
 201
 202         if (code == WEBSOCKET_CODE_NOT_SET && length == 0)
 203                 return websock_send(ws, 1, 0, 0, 0, OPCODE_CLOSE, NULL, 0);
 204
 205         /* checks the length */
 206         if (length > 123) {
 207                 errno = EINVAL;
 208                 return -1;
 209         }
 210
 211         /* prepare the buffer */
 212         buffer[0] = (unsigned char)((code >> 8) & 0xFF);
 213         buffer[1] = (unsigned char)(code & 0xFF);
 214
 215         /* Send server-side closing handshake */
 216         iov[0].iov_base = (void *)buffer;
 217         iov[0].iov_len = 2;
 218         iov[1].iov_base = (void *)data;
 219         iov[1].iov_len = length;
 220         return websock_send_v(ws, 1, 0, 0, 0, OPCODE_CLOSE, iov, 2);
 221 }
 222
 223 int websock_ping(struct websock *ws, const void *data, size_t length)
 224 {
 225         /* checks the length */
 226         if (length > 125) {
 227                 errno = EINVAL;
 228                 return -1;
 229         }
 230
 231         return websock_send(ws, 1, 0, 0, 0, OPCODE_PING, data, length);
 232 }
 233
 234 int websock_pong(struct websock *ws, const void *data, size_t length)
 235 {
 236         /* checks the length */
 237         if (length > 125) {
 238                 errno = EINVAL;
 239                 return -1;
 240         }
 241
 242         return websock_send(ws, 1, 0, 0, 0, OPCODE_PONG, data, length);
 243 }
 244
 245 int websock_text(struct websock *ws, int last, const void *text, size_t length)
 246 {
 247         return websock_send(ws, last, 0, 0, 0, OPCODE_TEXT, text, length);
 248 }
 249
 250 int websock_text_v(struct websock *ws, int last, const struct iovec *iovec, int count)
 251 {
 252         return websock_send_v(ws, last, 0, 0, 0, OPCODE_TEXT, iovec, count);
 253 }
 254
 255 int websock_binary(struct websock *ws, int last, const void *data, size_t length)
 256 {
 257         return websock_send(ws, last, 0, 0, 0, OPCODE_BINARY, data, length);
 258 }
 259
 260 int websock_binary_v(struct websock *ws, int last, const struct iovec *iovec, int count)
 261 {
 262         return websock_send_v(ws, last, 0, 0, 0, OPCODE_BINARY, iovec, count);
 263 }
 264
 265 int websock_continue(struct websock *ws, int last, const void *data, size_t length)
 266 {
 267         return websock_send(ws, last, 0, 0, 0, OPCODE_CONTINUATION, data, length);
 268 }
 269
 270 int websock_continue_v(struct websock *ws, int last, const struct iovec *iovec, int count)
 271 {
 272         return websock_send_v(ws, last, 0, 0, 0, OPCODE_CONTINUATION, iovec, count);
 273 }
 274
 275 int websock_error(struct websock *ws, uint16_t code, const void *data, size_t size)
 276 {
 277         int rc = websock_close(ws, code, data, size);
 278         if (ws->itf->on_error != NULL)
 279                 ws->itf->on_error(ws->closure, code, data, size);
 280         return rc;
 281 }
 282
 283 static int read_header(struct websock *ws)
 284 {
 285         if (ws->lenhead < ws->szhead) {
 286                 ssize_t rbc =
 287                     ws_read(ws, &ws->header[ws->lenhead], (size_t)(ws->szhead - ws->lenhead));
 288                 if (rbc < 0)
 289                         return -1;
 290                 ws->lenhead += (int)rbc;
 291         }
 292         return 0;
 293 }
 294
 295 static int check_control_header(struct websock *ws)
 296 {
 297         /* sanity checks */
 298         if (FRAME_GET_RSV1(ws->header[0]) != 0)
 299                 return 0;
 300         if (FRAME_GET_RSV2(ws->header[0]) != 0)
 301                 return 0;
 302         if (FRAME_GET_RSV3(ws->header[0]) != 0)
 303                 return 0;
 304         if (FRAME_GET_PAYLOAD_LEN(ws->header[1]) > 125)
 305                 return 0;
 306         if (FRAME_GET_OPCODE(ws->header[0]) == OPCODE_CLOSE)
 307                 return FRAME_GET_PAYLOAD_LEN(ws->header[1]) != 1;
 308         return 1;
 309 }
 310
 311 int websock_dispatch(struct websock *ws, int loop)
 312 {
 313         uint16_t code;
 314 loop:
 315         switch (ws->state) {
 316         case STATE_INIT:
 317                 ws->lenhead = 0;
 318                 ws->szhead = 2;
 319                 ws->state = STATE_START;
 320
 321         case STATE_START:
 322                 /* read the header */
 323                 if (read_header(ws))
 324                         return -1;
 325                 else if (ws->lenhead < ws->szhead)
 326                         return 0;
 327                 /* fast track */
 328                 switch (FRAME_GET_OPCODE(ws->header[0])) {
 329                 case OPCODE_CONTINUATION:
 330                 case OPCODE_TEXT:
 331                 case OPCODE_BINARY:
 332                         break;
 333                 case OPCODE_CLOSE:
 334                         if (!check_control_header(ws))
 335                                 goto protocol_error;
 336                         if (FRAME_GET_PAYLOAD_LEN(ws->header[1]))
 337                                 ws->szhead += 2;
 338                         break;
 339                 case OPCODE_PING:
 340                 case OPCODE_PONG:
 341                         if (!check_control_header(ws))
 342                                 goto protocol_error;
 343                 default:
 344                         break;
 345                 }
 346                 /* update heading size */
 347                 switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
 348                 case 127:
 349                         ws->szhead += 6;
 350                 case 126:
 351                         ws->szhead += 2;
 352                 default:
 353                         ws->szhead += 4 * FRAME_GET_MASK(ws->header[1]);
 354                 }
 355                 ws->state = STATE_LENGTH;
 356
 357         case STATE_LENGTH:
 358                 /* continue to read the header */
 359                 if (read_header(ws))
 360                         return -1;
 361                 else if (ws->lenhead < ws->szhead)
 362                         return 0;
 363
 364                 /* compute length */
 365                 switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
 366                 case 127:
 367                         ws->length = (((uint64_t) ws->header[2]) << 56)
 368                             | (((uint64_t) ws->header[3]) << 48)
 369                             | (((uint64_t) ws->header[4]) << 40)
 370                             | (((uint64_t) ws->header[5]) << 32)
 371                             | (((uint64_t) ws->header[6]) << 24)
 372                             | (((uint64_t) ws->header[7]) << 16)
 373                             | (((uint64_t) ws->header[8]) << 8)
 374                             | (uint64_t) ws->header[9];
 375                         break;
 376                 case 126:
 377                         ws->length = (((uint64_t) ws->header[2]) << 8)
 378                             | (uint64_t) ws->header[3];
 379                         break;
 380                 default:
 381                         ws->length = FRAME_GET_PAYLOAD_LEN(ws->header[1]);
 382                         break;
 383                 }
 384                 if (FRAME_GET_OPCODE(ws->header[0]) == OPCODE_CLOSE && ws->length != 0)
 385                         ws->length -= 2;
 386                 if (ws->length > ws->maxlength)
 387                         goto too_long_error;
 388
 389                 /* compute mask */
 390                 if (FRAME_GET_MASK(ws->header[1])) {
 391                         ((unsigned char *)&ws->mask)[0] = ws->header[ws->szhead - 4];
 392                         ((unsigned char *)&ws->mask)[1] = ws->header[ws->szhead - 3];
 393                         ((unsigned char *)&ws->mask)[2] = ws->header[ws->szhead - 2];
 394                         ((unsigned char *)&ws->mask)[3] = ws->header[ws->szhead - 1];
 395                 } else
 396                         ws->mask = 0;
 397
 398                 /* all heading fields are known, process */
 399                 ws->state = STATE_DATA;
 400                 if (ws->itf->on_extension != NULL) {
 401                         if (ws->itf->on_extension(ws->closure,
 402                                         FRAME_GET_FIN(ws->header[0]),
 403                                         FRAME_GET_RSV1(ws->header[0]),
 404                                         FRAME_GET_RSV2(ws->header[0]),
 405                                         FRAME_GET_RSV3(ws->header[0]),
 406                                         FRAME_GET_OPCODE(ws->header[0]),
 407                                         (size_t) ws->length)) {
 408                                 return 0;
 409                         }
 410                 }
 411
 412                 /* not an extension case */
 413                 if (FRAME_GET_RSV1(ws->header[0]) != 0)
 414                         goto protocol_error;
 415                 if (FRAME_GET_RSV2(ws->header[0]) != 0)
 416                         goto protocol_error;
 417                 if (FRAME_GET_RSV3(ws->header[0]) != 0)
 418                         goto protocol_error;
 419
 420                 /* handle */
 421                 switch (FRAME_GET_OPCODE(ws->header[0])) {
 422                 case OPCODE_CONTINUATION:
 423                         ws->itf->on_continue(ws->closure,
 424                                              FRAME_GET_FIN(ws->header[0]),
 425                                              (size_t) ws->length);
 426                         if (!loop)
 427                                 return 0;
 428                         break;
 429                 case OPCODE_TEXT:
 430                         ws->itf->on_text(ws->closure,
 431                                          FRAME_GET_FIN(ws->header[0]),
 432                                          (size_t) ws->length);
 433                         if (!loop)
 434                                 return 0;
 435                         break;
 436                 case OPCODE_BINARY:
 437                         ws->itf->on_binary(ws->closure,
 438                                            FRAME_GET_FIN(ws->header[0]),
 439                                            (size_t) ws->length);
 440                         if (!loop)
 441                                 return 0;
 442                         break;
 443                 case OPCODE_CLOSE:
 444                         if (ws->length == 0)
 445                                 code = WEBSOCKET_CODE_NOT_SET;
 446                         else {
 447                                 code = (uint16_t)(ws->header[ws->szhead - 2] & 0xff);
 448                                 code = (uint16_t)(code << 8);
 449                                 code = (uint16_t)(code | (uint16_t)(ws->header[ws->szhead - 1] & 0xff));
 450                         }
 451                         ws->itf->on_close(ws->closure, code, (size_t) ws->length);
 452                         return 0;
 453                 case OPCODE_PING:
 454                         if (ws->itf->on_ping)
 455                                 ws->itf->on_ping(ws->closure, ws->length);
 456                         else {
 457                                 websock_drop(ws);
 458                                 websock_pong(ws, NULL, 0);
 459                         }
 460                         ws->state = STATE_INIT;
 461                         if (!loop)
 462                                 return 0;
 463                         break;
 464                 case OPCODE_PONG:
 465                         if (ws->itf->on_pong)
 466                                 ws->itf->on_pong(ws->closure, ws->length);
 467                         else
 468                                 websock_drop(ws);
 469                         ws->state = STATE_INIT;
 470                         if (!loop)
 471                                 return 0;
 472                         break;
 473                 default:
 474                         goto protocol_error;
 475                 }
 476                 break;
 477
 478         case STATE_DATA:
 479                 if (ws->length)
 480                         return 0;
 481                 ws->state = STATE_INIT;
 482                 break;
 483         }
 484         goto loop;
 485
 486  too_long_error:
 487         websock_error(ws, WEBSOCKET_CODE_MESSAGE_TOO_LARGE, NULL, 0);
 488         return 0;
 489
 490  protocol_error:
 491         websock_error(ws, WEBSOCKET_CODE_PROTOCOL_ERROR, NULL, 0);
 492         return 0;
 493 }
 494
 495 static void unmask(struct websock * ws, void *buffer, size_t size)
 496 {
 497         uint32_t mask, *b32;
 498         uint8_t m, *b8;
 499
 500         mask = ws->mask;
 501         b8 = buffer;
 502         while (size && ((sizeof(uint32_t) - 1) & (uintptr_t) b8)) {
 503                 m = ((uint8_t *) & mask)[0];
 504                 ((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
 505                 ((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
 506                 ((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
 507                 ((uint8_t *) & mask)[3] = m;
 508                 *b8++ ^= m;
 509                 size--;
 510         }
 511         b32 = (uint32_t *) b8;
 512         while (size >= sizeof(uint32_t)) {
 513                 *b32++ ^= mask;
 514                 size -= sizeof(uint32_t);
 515         }
 516         b8 = (uint8_t *) b32;
 517         while (size) {
 518                 m = ((uint8_t *) & mask)[0];
 519                 ((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
 520                 ((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
 521                 ((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
 522                 ((uint8_t *) & mask)[3] = m;
 523                 *b8++ ^= m;
 524                 size--;
 525         }
 526         ws->mask = mask;
 527 }
 528
 529 ssize_t websock_read(struct websock * ws, void *buffer, size_t size)
 530 {
 531         ssize_t rc;
 532
 533         if (ws->state != STATE_DATA)
 534                 return 0;
 535
 536         if (size > ws->length)
 537                 size = (size_t) ws->length;
 538
 539         rc = ws_read(ws, buffer, size);
 540         if (rc > 0) {
 541                 size = (size_t) rc;
 542                 ws->length -= size;
 543
 544                 if (ws->mask != 0)
 545                         unmask(ws, buffer, size);
 546         }
 547         return rc;
 548 }
 549
 550 int websock_drop(struct websock *ws)
 551 {
 552         char buffer[8000];
 553
 554         while (ws->length)
 555                 if (websock_read(ws, buffer, sizeof buffer) < 0)
 556                         return -1;
 557         return 0;
 558 }
 559
 560 struct websock *websock_create_v13(const struct websock_itf *itf, void *closure)
 561 {
 562         struct websock *result = calloc(1, sizeof *result);
 563         if (result) {
 564                 result->itf = itf;
 565                 result->closure = closure;
 566                 result->maxlength = default_maxlength;
 567         }
 568         return result;
 569 }
 570
 571 void websock_destroy(struct websock *ws)
 572 {
 573         free(ws);
 574 }
 575
 576 void websock_set_default_max_length(size_t maxlen)
 577 {
 578         default_maxlength = maxlen;
 579 }
 580
 581 void websock_set_max_length(struct websock *ws, size_t maxlen)
 582 {
 583         ws->maxlength = (uint64_t)maxlen;
 584 }