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
  34 #define FRAME_GET_FIN(BYTE)         (((BYTE) >> 7) & 0x01)
  35 #define FRAME_GET_RSV1(BYTE)        (((BYTE) >> 6) & 0x01)
  36 #define FRAME_GET_RSV2(BYTE)        (((BYTE) >> 5) & 0x01)
  37 #define FRAME_GET_RSV3(BYTE)        (((BYTE) >> 4) & 0x01)
  38 #define FRAME_GET_OPCODE(BYTE)      ( (BYTE)       & 0x0F)
  39 #define FRAME_GET_MASK(BYTE)        (((BYTE) >> 7) & 0x01)
  40 #define FRAME_GET_PAYLOAD_LEN(BYTE) ( (BYTE)       & 0x7F)
  41
  42 #define FRAME_SET_FIN(BYTE)         (((BYTE) & 0x01) << 7)
  43 #define FRAME_SET_RSV1(BYTE)        (((BYTE) & 0x01) << 6)
  44 #define FRAME_SET_RSV2(BYTE)        (((BYTE) & 0x01) << 5)
  45 #define FRAME_SET_RSV3(BYTE)        (((BYTE) & 0x01) << 4)
  46 #define FRAME_SET_OPCODE(BYTE)      ((BYTE) & 0x0F)
  47 #define FRAME_SET_MASK(BYTE)        (((BYTE) & 0x01) << 7)
  48 #define FRAME_SET_LENGTH(X64, IDX)  (unsigned char)((sizeof(X64)) <= (IDX) ? 0 : (((X64) >> ((IDX)*8)) & 0xFF))
  49
  50 #define OPCODE_CONTINUATION 0x0
  51 #define OPCODE_TEXT         0x1
  52 #define OPCODE_BINARY       0x2
  53 #define OPCODE_CLOSE        0x8
  54 #define OPCODE_PING         0x9
  55 #define OPCODE_PONG         0xA
  56
  57 #define STATE_INIT    0
  58 #define STATE_START   1
  59 #define STATE_LENGTH  2
  60 #define STATE_DATA    3
  61
  62 struct websock {
  63         int state;
  64         uint64_t maxlength;
  65         int lenhead, szhead;
  66         uint64_t length;
  67         uint32_t mask;
  68         unsigned char header[14];       /* 2 + 8 + 4 */
  69         const struct websock_itf *itf;
  70         void *closure;
  71 };
  72
  73 static ssize_t ws_writev(struct websock *ws, const struct iovec *iov, int iovcnt)
  74 {
  75         return ws->itf->writev(ws->closure, iov, iovcnt);
  76 }
  77
  78 static ssize_t ws_readv(struct websock *ws, const struct iovec *iov, int iovcnt)
  79 {
  80         return ws->itf->readv(ws->closure, iov, iovcnt);
  81 }
  82
  83 #if 0
  84 static ssize_t ws_write(struct websock *ws, const void *buffer, size_t buffer_size)
  85 {
  86         struct iovec iov;
  87         iov.iov_base = (void *)buffer;  /* const cast */
  88         iov.iov_len = buffer_size;
  89         return ws_writev(ws, &iov, 1);
  90 }
  91 #endif
  92
  93 static ssize_t ws_read(struct websock *ws, void *buffer, size_t buffer_size)
  94 {
  95         struct iovec iov;
  96         iov.iov_base = buffer;
  97         iov.iov_len = buffer_size;
  98         return ws_readv(ws, &iov, 1);
  99 }
 100
 101 static int websock_send_internal_v(struct websock *ws, unsigned char first, const struct iovec *iovec, int count)
 102 {
 103         struct iovec iov[32];
 104         int i, j;
 105         size_t pos, size, len;
 106         ssize_t rc;
 107         unsigned char header[32];
 108
 109         /* checks count */
 110         if (count < 0 || (count + 1) > (int)(sizeof iov / sizeof * iov)) {
 111                 errno = EINVAL;
 112                 return -1;
 113         }
 114
 115         /* computes the size */
 116         size = 0;
 117         i = 1;
 118         for (j = 0 ; j < count ; j++) {
 119                 iov[i].iov_base = iovec[j].iov_base;
 120                 len = iovec[j].iov_len;
 121                 if (len != 0) {
 122                         iov[i].iov_len = len;
 123                         size += len;
 124                         i++;
 125                 }
 126         }
 127
 128         /* makes the header */
 129         pos = 0;
 130         header[pos++] = first;
 131         size = (uint64_t) size;
 132         if (size < 126) {
 133                 header[pos++] = FRAME_SET_MASK(0) | FRAME_SET_LENGTH(size, 0);
 134         } else {
 135                 if (size < 65536) {
 136                         header[pos++] = FRAME_SET_MASK(0) | 126;
 137                 } else {
 138                         header[pos++] = FRAME_SET_MASK(0) | 127;
 139                         header[pos++] = FRAME_SET_LENGTH(size, 7);
 140                         header[pos++] = FRAME_SET_LENGTH(size, 6);
 141                         header[pos++] = FRAME_SET_LENGTH(size, 5);
 142                         header[pos++] = FRAME_SET_LENGTH(size, 4);
 143                         header[pos++] = FRAME_SET_LENGTH(size, 3);
 144                         header[pos++] = FRAME_SET_LENGTH(size, 2);
 145                 }
 146                 header[pos++] = FRAME_SET_LENGTH(size, 1);
 147                 header[pos++] = FRAME_SET_LENGTH(size, 0);
 148         }
 149
 150         /* allocates the vec */
 151         iov[0].iov_base = header;
 152         iov[0].iov_len = pos;
 153         rc = ws_writev(ws, iov, i);
 154
 155         return rc < 0 ? -1 : 0;
 156 }
 157
 158 static int websock_send_internal(struct websock *ws, unsigned char first, const void *buffer, size_t size)
 159 {
 160         struct iovec iov;
 161
 162         iov.iov_base = (void *)buffer;
 163         iov.iov_len = size;
 164         return websock_send_internal_v(ws, first, &iov, 1);
 165 }
 166
 167 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)
 168 {
 169         unsigned char first = (unsigned char)(FRAME_SET_FIN(last)
 170                                 | FRAME_SET_RSV1(rsv1)
 171                                 | FRAME_SET_RSV1(rsv2)
 172                                 | FRAME_SET_RSV1(rsv3)
 173                                 | FRAME_SET_OPCODE(opcode));
 174         return websock_send_internal_v(ws, first, iovec, count);
 175 }
 176
 177 static inline int websock_send(struct websock *ws, int last, int rsv1, int rsv2, int rsv3, int opcode, const void *buffer, size_t size)
 178 {
 179         unsigned char first = (unsigned char)(FRAME_SET_FIN(last)
 180                                 | FRAME_SET_RSV1(rsv1)
 181                                 | FRAME_SET_RSV1(rsv2)
 182                                 | FRAME_SET_RSV1(rsv3)
 183                                 | FRAME_SET_OPCODE(opcode));
 184         return websock_send_internal(ws, first, buffer, size);
 185 }
 186
 187 int websock_close_empty(struct websock *ws)
 188 {
 189         return websock_close(ws, WEBSOCKET_CODE_NOT_SET, NULL, 0);
 190 }
 191
 192 int websock_close(struct websock *ws, uint16_t code, const void *data, size_t length)
 193 {
 194         unsigned char buffer[2];
 195         struct iovec iov[2];
 196
 197         if (code == WEBSOCKET_CODE_NOT_SET && length == 0)
 198                 return websock_send(ws, 1, 0, 0, 0, OPCODE_CLOSE, NULL, 0);
 199
 200         /* checks the length */
 201         if (length > 123) {
 202                 errno = EINVAL;
 203                 return -1;
 204         }
 205
 206         /* prepare the buffer */
 207         buffer[0] = (unsigned char)((code >> 8) & 0xFF);
 208         buffer[1] = (unsigned char)(code & 0xFF);
 209
 210         /* Send server-side closing handshake */
 211         iov[0].iov_base = (void *)buffer;
 212         iov[0].iov_len = 2;
 213         iov[1].iov_base = (void *)data;
 214         iov[1].iov_len = length;
 215         return websock_send_v(ws, 1, 0, 0, 0, OPCODE_CLOSE, iov, 2);
 216 }
 217
 218 int websock_ping(struct websock *ws, const void *data, size_t length)
 219 {
 220         /* checks the length */
 221         if (length > 125) {
 222                 errno = EINVAL;
 223                 return -1;
 224         }
 225
 226         return websock_send(ws, 1, 0, 0, 0, OPCODE_PING, data, length);
 227 }
 228
 229 int websock_pong(struct websock *ws, const void *data, size_t length)
 230 {
 231         /* checks the length */
 232         if (length > 125) {
 233                 errno = EINVAL;
 234                 return -1;
 235         }
 236
 237         return websock_send(ws, 1, 0, 0, 0, OPCODE_PONG, data, length);
 238 }
 239
 240 int websock_text(struct websock *ws, int last, const void *text, size_t length)
 241 {
 242         return websock_send(ws, last, 0, 0, 0, OPCODE_TEXT, text, length);
 243 }
 244
 245 int websock_text_v(struct websock *ws, int last, const struct iovec *iovec, int count)
 246 {
 247         return websock_send_v(ws, last, 0, 0, 0, OPCODE_TEXT, iovec, count);
 248 }
 249
 250 int websock_binary(struct websock *ws, int last, const void *data, size_t length)
 251 {
 252         return websock_send(ws, last, 0, 0, 0, OPCODE_BINARY, data, length);
 253 }
 254
 255 int websock_binary_v(struct websock *ws, int last, const struct iovec *iovec, int count)
 256 {
 257         return websock_send_v(ws, last, 0, 0, 0, OPCODE_BINARY, iovec, count);
 258 }
 259
 260 int websock_continue(struct websock *ws, int last, const void *data, size_t length)
 261 {
 262         return websock_send(ws, last, 0, 0, 0, OPCODE_CONTINUATION, data, length);
 263 }
 264
 265 int websock_continue_v(struct websock *ws, int last, const struct iovec *iovec, int count)
 266 {
 267         return websock_send_v(ws, last, 0, 0, 0, OPCODE_CONTINUATION, iovec, count);
 268 }
 269
 270 int websock_error(struct websock *ws, uint16_t code, const void *data, size_t size)
 271 {
 272         int rc = websock_close(ws, code, data, size);
 273         if (ws->itf->on_error != NULL)
 274                 ws->itf->on_error(ws->closure, code, data, size);
 275         return rc;
 276 }
 277
 278 static int read_header(struct websock *ws)
 279 {
 280         if (ws->lenhead < ws->szhead) {
 281                 ssize_t rbc =
 282                     ws_read(ws, &ws->header[ws->lenhead], (size_t)(ws->szhead - ws->lenhead));
 283                 if (rbc < 0)
 284                         return -1;
 285                 ws->lenhead += (int)rbc;
 286         }
 287         return 0;
 288 }
 289
 290 static int check_control_header(struct websock *ws)
 291 {
 292         /* sanity checks */
 293         if (FRAME_GET_RSV1(ws->header[0]) != 0)
 294                 return 0;
 295         if (FRAME_GET_RSV2(ws->header[0]) != 0)
 296                 return 0;
 297         if (FRAME_GET_RSV3(ws->header[0]) != 0)
 298                 return 0;
 299         if (FRAME_GET_PAYLOAD_LEN(ws->header[1]) > 125)
 300                 return 0;
 301         if (FRAME_GET_OPCODE(ws->header[0]) == OPCODE_CLOSE)
 302                 return FRAME_GET_PAYLOAD_LEN(ws->header[1]) != 1;
 303         return 1;
 304 }
 305
 306 int websock_dispatch(struct websock *ws, int loop)
 307 {
 308         uint16_t code;
 309 loop:
 310         switch (ws->state) {
 311         case STATE_INIT:
 312                 ws->lenhead = 0;
 313                 ws->szhead = 2;
 314                 ws->state = STATE_START;
 315
 316         case STATE_START:
 317                 /* read the header */
 318                 if (read_header(ws))
 319                         return -1;
 320                 else if (ws->lenhead < ws->szhead)
 321                         return 0;
 322                 /* fast track */
 323                 switch (FRAME_GET_OPCODE(ws->header[0])) {
 324                 case OPCODE_CONTINUATION:
 325                 case OPCODE_TEXT:
 326                 case OPCODE_BINARY:
 327                         break;
 328                 case OPCODE_CLOSE:
 329                         if (!check_control_header(ws))
 330                                 goto protocol_error;
 331                         if (FRAME_GET_PAYLOAD_LEN(ws->header[1]))
 332                                 ws->szhead += 2;
 333                         break;
 334                 case OPCODE_PING:
 335                 case OPCODE_PONG:
 336                         if (!check_control_header(ws))
 337                                 goto protocol_error;
 338                 default:
 339                         break;
 340                 }
 341                 /* update heading size */
 342                 switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
 343                 case 127:
 344                         ws->szhead += 6;
 345                 case 126:
 346                         ws->szhead += 2;
 347                 default:
 348                         ws->szhead += 4 * FRAME_GET_MASK(ws->header[1]);
 349                 }
 350                 ws->state = STATE_LENGTH;
 351
 352         case STATE_LENGTH:
 353                 /* continue to read the header */
 354                 if (read_header(ws))
 355                         return -1;
 356                 else if (ws->lenhead < ws->szhead)
 357                         return 0;
 358
 359                 /* compute length */
 360                 switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
 361                 case 127:
 362                         ws->length = (((uint64_t) ws->header[2]) << 56)
 363                             | (((uint64_t) ws->header[3]) << 48)
 364                             | (((uint64_t) ws->header[4]) << 40)
 365                             | (((uint64_t) ws->header[5]) << 32)
 366                             | (((uint64_t) ws->header[6]) << 24)
 367                             | (((uint64_t) ws->header[7]) << 16)
 368                             | (((uint64_t) ws->header[8]) << 8)
 369                             | (uint64_t) ws->header[9];
 370                         break;
 371                 case 126:
 372                         ws->length = (((uint64_t) ws->header[2]) << 8)
 373                             | (uint64_t) ws->header[3];
 374                         break;
 375                 default:
 376                         ws->length = FRAME_GET_PAYLOAD_LEN(ws->header[1]);
 377                         break;
 378                 }
 379                 if (FRAME_GET_OPCODE(ws->header[0]) == OPCODE_CLOSE && ws->length != 0)
 380                         ws->length -= 2;
 381                 if (ws->length > ws->maxlength)
 382                         goto too_long_error;
 383
 384                 /* compute mask */
 385                 if (FRAME_GET_MASK(ws->header[1])) {
 386                         ((unsigned char *)&ws->mask)[0] = ws->header[ws->szhead - 4];
 387                         ((unsigned char *)&ws->mask)[1] = ws->header[ws->szhead - 3];
 388                         ((unsigned char *)&ws->mask)[2] = ws->header[ws->szhead - 2];
 389                         ((unsigned char *)&ws->mask)[3] = ws->header[ws->szhead - 1];
 390                 } else
 391                         ws->mask = 0;
 392
 393                 /* all heading fields are known, process */
 394                 ws->state = STATE_DATA;
 395                 if (ws->itf->on_extension != NULL) {
 396                         if (ws->itf->on_extension(ws->closure,
 397                                         FRAME_GET_FIN(ws->header[0]),
 398                                         FRAME_GET_RSV1(ws->header[0]),
 399                                         FRAME_GET_RSV2(ws->header[0]),
 400                                         FRAME_GET_RSV3(ws->header[0]),
 401                                         FRAME_GET_OPCODE(ws->header[0]),
 402                                         (size_t) ws->length)) {
 403                                 return 0;
 404                         }
 405                 }
 406
 407                 /* not an extension case */
 408                 if (FRAME_GET_RSV1(ws->header[0]) != 0)
 409                         goto protocol_error;
 410                 if (FRAME_GET_RSV2(ws->header[0]) != 0)
 411                         goto protocol_error;
 412                 if (FRAME_GET_RSV3(ws->header[0]) != 0)
 413                         goto protocol_error;
 414
 415                 /* handle */
 416                 switch (FRAME_GET_OPCODE(ws->header[0])) {
 417                 case OPCODE_CONTINUATION:
 418                         ws->itf->on_continue(ws->closure,
 419                                              FRAME_GET_FIN(ws->header[0]),
 420                                              (size_t) ws->length);
 421                         if (!loop)
 422                                 return 0;
 423                         break;
 424                 case OPCODE_TEXT:
 425                         ws->itf->on_text(ws->closure,
 426                                          FRAME_GET_FIN(ws->header[0]),
 427                                          (size_t) ws->length);
 428                         if (!loop)
 429                                 return 0;
 430                         break;
 431                 case OPCODE_BINARY:
 432                         ws->itf->on_binary(ws->closure,
 433                                            FRAME_GET_FIN(ws->header[0]),
 434                                            (size_t) ws->length);
 435                         if (!loop)
 436                                 return 0;
 437                         break;
 438                 case OPCODE_CLOSE:
 439                         if (ws->length == 0)
 440                                 code = WEBSOCKET_CODE_NOT_SET;
 441                         else {
 442                                 code = (uint16_t)(ws->header[ws->szhead - 2] & 0xff);
 443                                 code = (uint16_t)(code << 8);
 444                                 code = (uint16_t)(code | (uint16_t)(ws->header[ws->szhead - 1] & 0xff));
 445                         }
 446                         ws->itf->on_close(ws->closure, code, (size_t) ws->length);
 447                         return 0;
 448                 case OPCODE_PING:
 449                         if (ws->itf->on_ping)
 450                                 ws->itf->on_ping(ws->closure, ws->length);
 451                         else {
 452                                 websock_drop(ws);
 453                                 websock_pong(ws, NULL, 0);
 454                         }
 455                         ws->state = STATE_INIT;
 456                         if (!loop)
 457                                 return 0;
 458                         break;
 459                 case OPCODE_PONG:
 460                         if (ws->itf->on_pong)
 461                                 ws->itf->on_pong(ws->closure, ws->length);
 462                         else
 463                                 websock_drop(ws);
 464                         ws->state = STATE_INIT;
 465                         if (!loop)
 466                                 return 0;
 467                         break;
 468                 default:
 469                         goto protocol_error;
 470                 }
 471                 break;
 472
 473         case STATE_DATA:
 474                 if (ws->length)
 475                         return 0;
 476                 ws->state = STATE_INIT;
 477                 break;
 478         }
 479         goto loop;
 480
 481  too_long_error:
 482         websock_error(ws, WEBSOCKET_CODE_MESSAGE_TOO_LARGE, NULL, 0);
 483         return 0;
 484
 485  protocol_error:
 486         websock_error(ws, WEBSOCKET_CODE_PROTOCOL_ERROR, NULL, 0);
 487         return 0;
 488 }
 489
 490 static void unmask(struct websock * ws, void *buffer, size_t size)
 491 {
 492         uint32_t mask, *b32;
 493         uint8_t m, *b8;
 494
 495         mask = ws->mask;
 496         b8 = buffer;
 497         while (size && ((sizeof(uint32_t) - 1) & (uintptr_t) b8)) {
 498                 m = ((uint8_t *) & mask)[0];
 499                 ((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
 500                 ((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
 501                 ((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
 502                 ((uint8_t *) & mask)[3] = m;
 503                 *b8++ ^= m;
 504                 size--;
 505         }
 506         b32 = (uint32_t *) b8;
 507         while (size >= sizeof(uint32_t)) {
 508                 *b32++ ^= mask;
 509                 size -= sizeof(uint32_t);
 510         }
 511         b8 = (uint8_t *) b32;
 512         while (size) {
 513                 m = ((uint8_t *) & mask)[0];
 514                 ((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
 515                 ((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
 516                 ((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
 517                 ((uint8_t *) & mask)[3] = m;
 518                 *b8++ ^= m;
 519                 size--;
 520         }
 521         ws->mask = mask;
 522 }
 523
 524 ssize_t websock_read(struct websock * ws, void *buffer, size_t size)
 525 {
 526         ssize_t rc;
 527
 528         if (ws->state != STATE_DATA)
 529                 return 0;
 530
 531         if (size > ws->length)
 532                 size = (size_t) ws->length;
 533
 534         rc = ws_read(ws, buffer, size);
 535         if (rc > 0) {
 536                 size = (size_t) rc;
 537                 ws->length -= size;
 538
 539                 if (ws->mask != 0)
 540                         unmask(ws, buffer, size);
 541         }
 542         return rc;
 543 }
 544
 545 int websock_drop(struct websock *ws)
 546 {
 547         char buffer[8000];
 548
 549         while (ws->length)
 550                 if (websock_read(ws, buffer, sizeof buffer) < 0)
 551                         return -1;
 552         return 0;
 553 }
 554
 555 struct websock *websock_create_v13(const struct websock_itf *itf, void *closure)
 556 {
 557         struct websock *result = calloc(1, sizeof *result);
 558         if (result) {
 559                 result->itf = itf;
 560                 result->closure = closure;
 561                 result->maxlength = 65000;
 562         }
 563         return result;
 564 }
 565
 566 void websock_destroy(struct websock *ws)
 567 {
 568         free(ws);
 569 }