src/websock.c

   1 /*
   2  * Copyright 2016 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)(((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(struct websock *ws, unsigned char first, const void *buffer, size_t size)
 102 {
 103         struct iovec iov[2];
 104         size_t pos;
 105         ssize_t rc;
 106         unsigned char header[32];
 107
 108         pos = 0;
 109         header[pos++] = first;
 110         size = (uint64_t) size;
 111         if (size < 126) {
 112                 header[pos++] = FRAME_SET_MASK(0) | FRAME_SET_LENGTH(size, 0);
 113         } else {
 114                 if (size < 65536) {
 115                         header[pos++] = FRAME_SET_MASK(0) | 126;
 116                 } else {
 117                         header[pos++] = FRAME_SET_MASK(0) | 127;
 118                         header[pos++] = FRAME_SET_LENGTH(size, 7);
 119                         header[pos++] = FRAME_SET_LENGTH(size, 6);
 120                         header[pos++] = FRAME_SET_LENGTH(size, 5);
 121                         header[pos++] = FRAME_SET_LENGTH(size, 4);
 122                         header[pos++] = FRAME_SET_LENGTH(size, 3);
 123                         header[pos++] = FRAME_SET_LENGTH(size, 2);
 124                 }
 125                 header[pos++] = FRAME_SET_LENGTH(size, 1);
 126                 header[pos++] = FRAME_SET_LENGTH(size, 0);
 127         }
 128
 129         iov[0].iov_base = header;
 130         iov[0].iov_len = pos;
 131         iov[1].iov_base = (void *)buffer;       /* const cast */
 132         iov[1].iov_len = size;
 133
 134         rc = ws_writev(ws, iov, 1 + !!size);
 135
 136         return rc < 0 ? -1 : 0;
 137 }
 138
 139 static inline int websock_send(struct websock *ws, int last, int rsv1, int rsv2, int rsv3, int opcode, const void *buffer, size_t size)
 140 {
 141         unsigned char first = (unsigned char)(FRAME_SET_FIN(last)
 142                                 | FRAME_SET_RSV1(rsv1)
 143                                 | FRAME_SET_RSV1(rsv2)
 144                                 | FRAME_SET_RSV1(rsv3)
 145                                 | FRAME_SET_OPCODE(opcode));
 146         return websock_send_internal(ws, first, buffer, size);
 147 }
 148
 149 int websock_close(struct websock *ws)
 150 {
 151         return websock_send(ws, 1, 0, 0, 0, OPCODE_CLOSE, NULL, 0);
 152 }
 153
 154 int websock_close_code(struct websock *ws, uint16_t code, const void *data, size_t length)
 155 {
 156         unsigned char buffer[125];
 157
 158         /* checks the length */
 159         if (length > 123) {
 160                 errno = EINVAL;
 161                 return -1;
 162         }
 163
 164         /* prepare the buffer */
 165         buffer[0] = (unsigned char)((code >> 8) & 0xFF);
 166         buffer[1] = (unsigned char)(code & 0xFF);
 167         if (length != 0)
 168                 memcpy(&buffer[2], data, length);
 169
 170         /* Send server-side closing handshake */
 171         return websock_send(ws, 1, 0, 0, 0, OPCODE_CLOSE, buffer, 2 + length);
 172 }
 173
 174 int websock_ping(struct websock *ws, const void *data, size_t length)
 175 {
 176         /* checks the length */
 177         if (length > 125) {
 178                 errno = EINVAL;
 179                 return -1;
 180         }
 181
 182         return websock_send(ws, 1, 0, 0, 0, OPCODE_PING, data, length);
 183 }
 184
 185 int websock_pong(struct websock *ws, const void *data, size_t length)
 186 {
 187         /* checks the length */
 188         if (length > 125) {
 189                 errno = EINVAL;
 190                 return -1;
 191         }
 192
 193         return websock_send(ws, 1, 0, 0, 0, OPCODE_PONG, data, length);
 194 }
 195
 196 int websock_text(struct websock *ws, int last, const char *text, size_t length)
 197 {
 198         return websock_send(ws, last, 0, 0, 0, OPCODE_TEXT, text, length);
 199 }
 200
 201 int websock_binary(struct websock *ws, int last, const void *data, size_t length)
 202 {
 203         return websock_send(ws, last, 0, 0, 0, OPCODE_BINARY, data, length);
 204 }
 205
 206 static int read_header(struct websock *ws)
 207 {
 208         if (ws->lenhead < ws->szhead) {
 209                 ssize_t rbc =
 210                     ws_read(ws, &ws->header[ws->lenhead], (size_t)(ws->szhead - ws->lenhead));
 211                 if (rbc < 0)
 212                         return -1;
 213                 ws->lenhead += (int)rbc;
 214         }
 215         return 0;
 216 }
 217
 218 static int check_control_header(struct websock *ws)
 219 {
 220         /* sanity checks */
 221         if (FRAME_GET_RSV1(ws->header[0]) != 0)
 222                 return 0;
 223         if (FRAME_GET_RSV2(ws->header[0]) != 0)
 224                 return 0;
 225         if (FRAME_GET_RSV3(ws->header[0]) != 0)
 226                 return 0;
 227         if (FRAME_GET_PAYLOAD_LEN(ws->header[1]) > 125)
 228                 return 0;
 229         if (FRAME_GET_OPCODE(ws->header[0]) == OPCODE_CLOSE)
 230                 return FRAME_GET_PAYLOAD_LEN(ws->header[1]) != 1;
 231         return 1;
 232 }
 233
 234 int websock_dispatch(struct websock *ws)
 235 {
 236         uint16_t code;
 237 loop:
 238         switch (ws->state) {
 239         case STATE_INIT:
 240                 ws->lenhead = 0;
 241                 ws->szhead = 2;
 242                 ws->state = STATE_START;
 243
 244         case STATE_START:
 245                 /* read the header */
 246                 if (read_header(ws))
 247                         return -1;
 248                 else if (ws->lenhead < ws->szhead)
 249                         return 0;
 250                 /* fast track */
 251                 switch (FRAME_GET_OPCODE(ws->header[0])) {
 252                 case OPCODE_CONTINUATION:
 253                 case OPCODE_TEXT:
 254                 case OPCODE_BINARY:
 255                         break;
 256                 case OPCODE_CLOSE:
 257                         if (!check_control_header(ws))
 258                                 goto protocol_error;
 259                         if (FRAME_GET_PAYLOAD_LEN(ws->header[1]))
 260                                 ws->szhead += 2;
 261                         break;
 262                 case OPCODE_PING:
 263                 case OPCODE_PONG:
 264                         if (!check_control_header(ws))
 265                                 goto protocol_error;
 266                 default:
 267                         break;
 268                 }
 269                 /* update heading size */
 270                 switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
 271                 case 127:
 272                         ws->szhead += 6;
 273                 case 126:
 274                         ws->szhead += 2;
 275                 default:
 276                         ws->szhead += 4 * FRAME_GET_MASK(ws->header[1]);
 277                 }
 278                 ws->state = STATE_LENGTH;
 279
 280         case STATE_LENGTH:
 281                 /* continue to read the header */
 282                 if (read_header(ws))
 283                         return -1;
 284                 else if (ws->lenhead < ws->szhead)
 285                         return 0;
 286
 287                 /* compute length */
 288                 switch (FRAME_GET_PAYLOAD_LEN(ws->header[1])) {
 289                 case 127:
 290                         ws->length = (((uint64_t) ws->header[2]) << 56)
 291                             | (((uint64_t) ws->header[3]) << 48)
 292                             | (((uint64_t) ws->header[4]) << 40)
 293                             | (((uint64_t) ws->header[5]) << 32)
 294                             | (((uint64_t) ws->header[6]) << 24)
 295                             | (((uint64_t) ws->header[7]) << 16)
 296                             | (((uint64_t) ws->header[8]) << 8)
 297                             | (uint64_t) ws->header[9];
 298                         break;
 299                 case 126:
 300                         ws->length = (((uint64_t) ws->header[2]) << 8)
 301                             | (uint64_t) ws->header[3];
 302                         break;
 303                 default:
 304                         ws->length = FRAME_GET_PAYLOAD_LEN(ws->header[1]);
 305                         break;
 306                 }
 307                 if (FRAME_GET_OPCODE(ws->header[0]) == OPCODE_CLOSE && ws->length != 0)
 308                         ws->length -= 2;
 309                 if (ws->length > ws->maxlength)
 310                         goto too_long_error;
 311
 312                 /* compute mask */
 313                 if (FRAME_GET_MASK(ws->header[1])) {
 314                         ((unsigned char *)&ws->mask)[0] = ws->header[ws->szhead - 4];
 315                         ((unsigned char *)&ws->mask)[1] = ws->header[ws->szhead - 3];
 316                         ((unsigned char *)&ws->mask)[2] = ws->header[ws->szhead - 2];
 317                         ((unsigned char *)&ws->mask)[3] = ws->header[ws->szhead - 1];
 318                 } else
 319                         ws->mask = 0;
 320
 321                 /* all heading fields are known, process */
 322                 ws->state = STATE_DATA;
 323                 if (ws->itf->on_extension != NULL) {
 324                         if (ws->itf->on_extension(ws->closure,
 325                                         FRAME_GET_FIN(ws->header[0]),
 326                                         FRAME_GET_RSV1(ws->header[0]),
 327                                         FRAME_GET_RSV2(ws->header[0]),
 328                                         FRAME_GET_RSV3(ws->header[0]),
 329                                         FRAME_GET_OPCODE(ws->header[0]),
 330                                         (size_t) ws->length)) {
 331                                 return 0;
 332                         }
 333                 }
 334
 335                 /* not an extension case */
 336                 if (FRAME_GET_RSV1(ws->header[0]) != 0)
 337                         goto protocol_error;
 338                 if (FRAME_GET_RSV2(ws->header[0]) != 0)
 339                         goto protocol_error;
 340                 if (FRAME_GET_RSV3(ws->header[0]) != 0)
 341                         goto protocol_error;
 342
 343                 /* handle */
 344                 switch (FRAME_GET_OPCODE(ws->header[0])) {
 345                 case OPCODE_CONTINUATION:
 346                         ws->itf->on_continue(ws->closure,
 347                                              FRAME_GET_FIN(ws->header[0]),
 348                                              (size_t) ws->length);
 349                         break;
 350                 case OPCODE_TEXT:
 351                         ws->itf->on_text(ws->closure,
 352                                          FRAME_GET_FIN(ws->header[0]),
 353                                          (size_t) ws->length);
 354                         break;
 355                 case OPCODE_BINARY:
 356                         ws->itf->on_binary(ws->closure,
 357                                            FRAME_GET_FIN(ws->header[0]),
 358                                            (size_t) ws->length);
 359                         break;
 360                 case OPCODE_CLOSE:
 361                         if (ws->length == 0)
 362                                 code = WEBSOCKET_CODE_NOT_SET;
 363                         else {
 364                                 code = (uint16_t)(ws->header[ws->szhead - 2] & 0xff);
 365                                 code = (uint16_t)(code << 8);
 366                                 code = (uint16_t)(code | (uint16_t)(ws->header[ws->szhead - 1] & 0xff));
 367                         }
 368                         ws->itf->on_close(ws->closure, code, (size_t) ws->length);
 369                         return 0;
 370                 case OPCODE_PING:
 371                         if (ws->itf->on_ping)
 372                                 ws->itf->on_ping(ws->closure, ws->length);
 373                         else {
 374                                 websock_drop(ws);
 375                                 websock_pong(ws, NULL, 0);
 376                         }
 377                         ws->state = STATE_INIT;
 378                         break;
 379                 case OPCODE_PONG:
 380                         if (ws->itf->on_pong)
 381                                 ws->itf->on_pong(ws->closure, ws->length);
 382                         else
 383                                 websock_drop(ws);
 384                         ws->state = STATE_INIT;
 385                         break;
 386                 default:
 387                         goto protocol_error;
 388                 }
 389                 break;
 390
 391         case STATE_DATA:
 392                 if (ws->length)
 393                         return 0;
 394                 ws->state = STATE_INIT;
 395                 break;
 396         }
 397         goto loop;
 398
 399  too_long_error:
 400         websock_close_code(ws, WEBSOCKET_CODE_MESSAGE_TOO_LARGE, NULL, 0);
 401         return 0;
 402
 403  protocol_error:
 404         websock_close_code(ws, WEBSOCKET_CODE_PROTOCOL_ERROR, NULL, 0);
 405         return 0;
 406 }
 407
 408 ssize_t websock_read(struct websock * ws, void *buffer, size_t size)
 409 {
 410         uint32_t mask, *b32;
 411         uint8_t m, *b8;
 412         ssize_t rc;
 413
 414         if (ws->state != STATE_DATA)
 415                 return 0;
 416
 417         if (size > ws->length)
 418                 size = (size_t) ws->length;
 419
 420         rc = ws_read(ws, buffer, size);
 421         if (rc > 0) {
 422                 size = (size_t) rc;
 423                 ws->length -= size;
 424
 425                 if (ws->mask) {
 426                         mask = ws->mask;
 427                         b8 = buffer;
 428                         while (size && ((sizeof(uint32_t) - 1) & (uintptr_t) b8)) {
 429                                 m = ((uint8_t *) & mask)[0];
 430                                 ((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
 431                                 ((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
 432                                 ((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
 433                                 ((uint8_t *) & mask)[3] = m;
 434                                 *b8++ ^= m;
 435                                 size--;
 436                         }
 437                         b32 = (uint32_t *) b8;
 438                         while (size >= sizeof(uint32_t)) {
 439                                 *b32++ ^= mask;
 440                                 size -= sizeof(uint32_t);
 441                         }
 442                         b8 = (uint8_t *) b32;
 443                         while (size) {
 444                                 m = ((uint8_t *) & mask)[0];
 445                                 ((uint8_t *) & mask)[0] = ((uint8_t *) & mask)[1];
 446                                 ((uint8_t *) & mask)[1] = ((uint8_t *) & mask)[2];
 447                                 ((uint8_t *) & mask)[2] = ((uint8_t *) & mask)[3];
 448                                 ((uint8_t *) & mask)[3] = m;
 449                                 *b8++ ^= m;
 450                                 size--;
 451                         }
 452                         ws->mask = mask;
 453                 }
 454         }
 455         return rc;
 456 }
 457
 458 int websock_drop(struct websock *ws)
 459 {
 460         char buffer[8000];
 461
 462         while (ws->length)
 463                 if (ws_read(ws, buffer, sizeof buffer) < 0)
 464                         return -1;
 465         return 0;
 466 }
 467
 468 struct websock *websock_create_v13(const struct websock_itf *itf, void *closure)
 469 {
 470         struct websock *result = calloc(1, sizeof *result);
 471         if (result) {
 472                 result->itf = itf;
 473                 result->closure = closure;
 474                 result->maxlength = 65000;
 475         }
 476         return result;
 477 }
 478
 479 void websock_destroy(struct websock *ws)
 480 {
 481         free(ws);
 482 }