summaryrefslogtreecommitdiffstats
path: root/Utilities/cmcurl/lib/mqtt.c
blob: d09aab4eefed5195aba320aa3b4c950016d43641 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 * Copyright (C) 2019, Björn Stenberg, <bjorn@haxx.se>
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ***************************************************************************/

#include "curl_setup.h"

#ifdef CURL_ENABLE_MQTT

#include "urldata.h"
#include <curl/curl.h>
#include "transfer.h"
#include "sendf.h"
#include "progress.h"
#include "mqtt.h"
#include "select.h"
#include "strdup.h"
#include "url.h"
#include "escape.h"
#include "warnless.h"
#include "curl_printf.h"
#include "curl_memory.h"
#include "multiif.h"
#include "rand.h"

/* The last #include file should be: */
#include "memdebug.h"

#define MQTT_MSG_CONNECT   0x10
#define MQTT_MSG_CONNACK   0x20
#define MQTT_MSG_PUBLISH   0x30
#define MQTT_MSG_SUBSCRIBE 0x82
#define MQTT_MSG_SUBACK    0x90
#define MQTT_MSG_DISCONNECT 0xe0

#define MQTT_CONNACK_LEN 2
#define MQTT_SUBACK_LEN 3
#define MQTT_CLIENTID_LEN 12 /* "curl0123abcd" */

/*
 * Forward declarations.
 */

static CURLcode mqtt_do(struct connectdata *conn, bool *done);
static CURLcode mqtt_doing(struct connectdata *conn, bool *done);
static int mqtt_getsock(struct connectdata *conn, curl_socket_t *sock);
static CURLcode mqtt_setup_conn(struct connectdata *conn);

/*
 * MQTT protocol handler.
 */

const struct Curl_handler Curl_handler_mqtt = {
  "MQTT",                             /* scheme */
  mqtt_setup_conn,                    /* setup_connection */
  mqtt_do,                            /* do_it */
  ZERO_NULL,                          /* done */
  ZERO_NULL,                          /* do_more */
  ZERO_NULL,                          /* connect_it */
  ZERO_NULL,                          /* connecting */
  mqtt_doing,                         /* doing */
  ZERO_NULL,                          /* proto_getsock */
  mqtt_getsock,                       /* doing_getsock */
  ZERO_NULL,                          /* domore_getsock */
  ZERO_NULL,                          /* perform_getsock */
  ZERO_NULL,                          /* disconnect */
  ZERO_NULL,                          /* readwrite */
  ZERO_NULL,                          /* connection_check */
  PORT_MQTT,                          /* defport */
  CURLPROTO_MQTT,                     /* protocol */
  PROTOPT_NONE                        /* flags */
};

static CURLcode mqtt_setup_conn(struct connectdata *conn)
{
  /* allocate the HTTP-specific struct for the Curl_easy, only to survive
     during this request */
  struct MQTT *mq;
  struct Curl_easy *data = conn->data;
  DEBUGASSERT(data->req.protop == NULL);

  mq = calloc(1, sizeof(struct MQTT));
  if(!mq)
    return CURLE_OUT_OF_MEMORY;
  data->req.protop = mq;
  return CURLE_OK;
}

static CURLcode mqtt_send(struct connectdata *conn,
                          char *buf, size_t len)
{
  CURLcode result = CURLE_OK;
  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
  struct Curl_easy *data = conn->data;
  struct MQTT *mq = data->req.protop;
  ssize_t n;
  result = Curl_write(conn, sockfd, buf, len, &n);
  if(!result && data->set.verbose)
    Curl_debug(data, CURLINFO_HEADER_OUT, buf, (size_t)n);
  if(len != (size_t)n) {
    size_t nsend = len - n;
    char *sendleftovers = Curl_memdup(&buf[n], nsend);
    if(!sendleftovers)
      return CURLE_OUT_OF_MEMORY;
    mq->sendleftovers = sendleftovers;
    mq->nsend = nsend;
  }
  return result;
}

/* Generic function called by the multi interface to figure out what socket(s)
   to wait for and for what actions during the DOING and PROTOCONNECT
   states */
static int mqtt_getsock(struct connectdata *conn,
                        curl_socket_t *sock)
{
  sock[0] = conn->sock[FIRSTSOCKET];
  return GETSOCK_READSOCK(FIRSTSOCKET);
}

static CURLcode mqtt_connect(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  const size_t client_id_offset = 14;
  const size_t packetlen = client_id_offset + MQTT_CLIENTID_LEN;
  char client_id[MQTT_CLIENTID_LEN + 1] = "curl";
  const size_t curl_len = strlen("curl");
  char packet[32] = {
    MQTT_MSG_CONNECT,  /* packet type */
    0x00,              /* remaining length */
    0x00, 0x04,        /* protocol length */
    'M','Q','T','T',   /* protocol name */
    0x04,              /* protocol level */
    0x02,              /* CONNECT flag: CleanSession */
    0x00, 0x3c,        /* keep-alive 0 = disabled */
    0x00, 0x00         /* payload1 length */
  };
  packet[1] = (packetlen - 2) & 0x7f;
  packet[client_id_offset - 1] = MQTT_CLIENTID_LEN;

  result = Curl_rand_hex(conn->data, (unsigned char *)&client_id[curl_len],
                         MQTT_CLIENTID_LEN - curl_len + 1);
  memcpy(&packet[client_id_offset], client_id, MQTT_CLIENTID_LEN);
  infof(conn->data, "Using client id '%s'\n", client_id);
  if(!result)
    result = mqtt_send(conn, packet, packetlen);
  return result;
}

static CURLcode mqtt_disconnect(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  result = mqtt_send(conn, (char *)"\xe0\x00", 2);
  return result;
}

static CURLcode mqtt_verify_connack(struct connectdata *conn)
{
  CURLcode result;
  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
  unsigned char readbuf[MQTT_CONNACK_LEN];
  ssize_t nread;
  struct Curl_easy *data = conn->data;

  result = Curl_read(conn, sockfd, (char *)readbuf, MQTT_CONNACK_LEN, &nread);
  if(result)
    goto fail;

  if(data->set.verbose)
    Curl_debug(data, CURLINFO_HEADER_IN, (char *)readbuf, (size_t)nread);

  /* fixme */
  if(nread < MQTT_CONNACK_LEN) {
    result = CURLE_WEIRD_SERVER_REPLY;
    goto fail;
  }

  /* verify CONNACK */
  if(readbuf[0] != 0x00 || readbuf[1] != 0x00) {
    failf(data, "Expected %02x%02x but got %02x%02x",
          0x00, 0x00, readbuf[0], readbuf[1]);
    result = CURLE_WEIRD_SERVER_REPLY;
  }

fail:
  return result;
}

static CURLcode mqtt_get_topic(struct connectdata *conn,
                               char **topic, size_t *topiclen)
{
  CURLcode result = CURLE_OK;
  char *path = conn->data->state.up.path;

  if(strlen(path) > 1) {
    result = Curl_urldecode(conn->data, path + 1, 0, topic, topiclen, FALSE);
  }
  else {
    failf(conn->data, "Error: No topic specified.");
    result = CURLE_URL_MALFORMAT;
  }
  return result;
}


static int mqtt_encode_len(char *buf, size_t len)
{
  unsigned char encoded;
  int i;

  for(i = 0; (len > 0) && (i<4); i++) {
    encoded = len % 0x80;
    len /= 0x80;
    if(len)
      encoded |= 0x80;
    buf[i] = encoded;
  }

  return i;
}

static CURLcode mqtt_subscribe(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  char *topic = NULL;
  size_t topiclen;
  unsigned char *packet = NULL;
  size_t packetlen;
  char encodedsize[4];
  size_t n;

  result = mqtt_get_topic(conn, &topic, &topiclen);
  if(result)
    goto fail;

  conn->proto.mqtt.packetid++;

  packetlen = topiclen + 5; /* packetid + topic (has a two byte length field)
                               + 2 bytes topic length + QoS byte */
  n = mqtt_encode_len((char *)encodedsize, packetlen);
  packetlen += n + 1; /* add one for the control packet type byte */

  packet = malloc(packetlen);
  if(!packet) {
    result = CURLE_OUT_OF_MEMORY;
    goto fail;
  }

  packet[0] = MQTT_MSG_SUBSCRIBE;
  memcpy(&packet[1], encodedsize, n);
  packet[1 + n] = (conn->proto.mqtt.packetid >> 8) & 0xff;
  packet[2 + n] = conn->proto.mqtt.packetid & 0xff;
  packet[3 + n] = (topiclen >> 8) & 0xff;
  packet[4 + n ] = topiclen & 0xff;
  memcpy(&packet[5 + n], topic, topiclen);
  packet[5 + n + topiclen] = 0; /* QoS zero */

  result = mqtt_send(conn, (char *)packet, packetlen);

fail:
  free(topic);
  free(packet);
  return result;
}

/*
 * Called when the first byte was already read.
 */
static CURLcode mqtt_verify_suback(struct connectdata *conn)
{
  CURLcode result;
  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
  unsigned char readbuf[MQTT_SUBACK_LEN];
  ssize_t nread;
  struct mqtt_conn *mqtt = &conn->proto.mqtt;

  result = Curl_read(conn, sockfd, (char *)readbuf, MQTT_SUBACK_LEN, &nread);
  if(result)
    goto fail;

  if(conn->data->set.verbose)
    Curl_debug(conn->data, CURLINFO_HEADER_IN, (char *)readbuf, (size_t)nread);

  /* fixme */
  if(nread < MQTT_SUBACK_LEN) {
    result = CURLE_WEIRD_SERVER_REPLY;
    goto fail;
  }

  /* verify SUBACK */
  if(readbuf[0] != ((mqtt->packetid >> 8) & 0xff) ||
     readbuf[1] != (mqtt->packetid & 0xff) ||
     readbuf[2] != 0x00)
    result = CURLE_WEIRD_SERVER_REPLY;

fail:
  return result;
}

static CURLcode mqtt_publish(struct connectdata *conn)
{
  CURLcode result;
  char *payload = conn->data->set.postfields;
  size_t payloadlen = (size_t)conn->data->set.postfieldsize;
  char *topic = NULL;
  size_t topiclen;
  unsigned char *pkt = NULL;
  size_t i = 0;
  size_t remaininglength;
  size_t encodelen;
  char encodedbytes[4];

  result = mqtt_get_topic(conn, &topic, &topiclen);
  if(result)
    goto fail;

  remaininglength = payloadlen + 2 + topiclen;
  encodelen = mqtt_encode_len(encodedbytes, remaininglength);

  /* add the control byte and the encoded remaining length */
  pkt = malloc(remaininglength + 1 + encodelen);
  if(!pkt) {
    result = CURLE_OUT_OF_MEMORY;
    goto fail;
  }

  /* assemble packet */
  pkt[i++] = MQTT_MSG_PUBLISH;
  memcpy(&pkt[i], encodedbytes, encodelen);
  i += encodelen;
  pkt[i++] = (topiclen >> 8) & 0xff;
  pkt[i++] = (topiclen & 0xff);
  memcpy(&pkt[i], topic, topiclen);
  i += topiclen;
  memcpy(&pkt[i], payload, payloadlen);
  i += payloadlen;
  result = mqtt_send(conn, (char *)pkt, i);

fail:
  free(pkt);
  free(topic);
  return result;
}

static size_t mqtt_decode_len(unsigned char *buf,
                              size_t buflen, size_t *lenbytes)
{
  size_t len = 0;
  size_t mult = 1;
  size_t i;
  unsigned char encoded = 128;

  for(i = 0; (i < buflen) && (encoded & 128); i++) {
    encoded = buf[i];
    len += (encoded & 127) * mult;
    mult *= 128;
  }

  if(lenbytes)
    *lenbytes = i;

  return len;
}

#ifdef CURLDEBUG
static const char *statenames[]={
  "MQTT_FIRST",
  "MQTT_REMAINING_LENGTH",
  "MQTT_CONNACK",
  "MQTT_SUBACK",
  "MQTT_SUBACK_COMING",
  "MQTT_PUBWAIT",
  "MQTT_PUB_REMAIN",

  "NOT A STATE"
};
#endif

/* The only way to change state */
static void mqstate(struct connectdata *conn,
                    enum mqttstate state,
                    enum mqttstate nextstate) /* used if state == FIRST */
{
  struct mqtt_conn *mqtt = &conn->proto.mqtt;
#ifdef CURLDEBUG
  infof(conn->data, "%s (from %s) (next is %s)\n",
        statenames[state],
        statenames[mqtt->state],
        (state == MQTT_FIRST)? statenames[nextstate] : "");
#endif
  mqtt->state = state;
  if(state == MQTT_FIRST)
    mqtt->nextstate = nextstate;
}


/* for the publish packet */
#define MQTT_HEADER_LEN 5    /* max 5 bytes */

static CURLcode mqtt_read_publish(struct connectdata *conn,
                                  bool *done)
{
  CURLcode result = CURLE_OK;
  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
  ssize_t nread;
  struct Curl_easy *data = conn->data;
  unsigned char *pkt = (unsigned char *)data->state.buffer;
  size_t remlen;
  struct mqtt_conn *mqtt = &conn->proto.mqtt;
  struct MQTT *mq = data->req.protop;
  unsigned char packet;

  switch(mqtt->state) {
  MQTT_SUBACK_COMING:
  case MQTT_SUBACK_COMING:
    result = mqtt_verify_suback(conn);
    if(result)
      break;

    mqstate(conn, MQTT_FIRST, MQTT_PUBWAIT);
    break;

  case MQTT_SUBACK:
  case MQTT_PUBWAIT:
    /* we are expecting PUBLISH or SUBACK */
    packet = mq->firstbyte & 0xf0;
    if(packet == MQTT_MSG_PUBLISH)
      mqstate(conn, MQTT_PUB_REMAIN, MQTT_NOSTATE);
    else if(packet == MQTT_MSG_SUBACK) {
      mqstate(conn, MQTT_SUBACK_COMING, MQTT_NOSTATE);
      goto MQTT_SUBACK_COMING;
    }
    else if(packet == MQTT_MSG_DISCONNECT) {
      infof(data, "Got DISCONNECT\n");
      *done = TRUE;
      goto end;
    }
    else {
      result = CURLE_WEIRD_SERVER_REPLY;
      goto end;
    }

    /* -- switched state -- */
    remlen = mq->remaining_length;
    infof(data, "Remaining length: %zd bytes\n", remlen);
    Curl_pgrsSetDownloadSize(data, remlen);
    data->req.bytecount = 0;
    data->req.size = remlen;
    mq->npacket = remlen; /* get this many bytes */
    /* FALLTHROUGH */
  case MQTT_PUB_REMAIN: {
    /* read rest of packet, but no more. Cap to buffer size */
    struct SingleRequest *k = &data->req;
    size_t rest = mq->npacket;
    if(rest > (size_t)data->set.buffer_size)
      rest = (size_t)data->set.buffer_size;
    result = Curl_read(conn, sockfd, (char *)pkt, rest, &nread);
    if(result) {
      if(CURLE_AGAIN == result) {
        infof(data, "EEEE AAAAGAIN\n");
      }
      goto end;
    }
    if(!nread) {
      infof(data, "server disconnected\n");
      result = CURLE_PARTIAL_FILE;
      goto end;
    }
    if(data->set.verbose)
      Curl_debug(data, CURLINFO_DATA_IN, (char *)pkt, (size_t)nread);

    mq->npacket -= nread;
    k->bytecount += nread;
    Curl_pgrsSetDownloadCounter(data, k->bytecount);

    /* if QoS is set, message contains packet id */

    result = Curl_client_write(conn, CLIENTWRITE_BODY, (char *)pkt, nread);
    if(result)
      goto end;

    if(!mq->npacket)
      /* no more PUBLISH payload, back to subscribe wait state */
      mqstate(conn, MQTT_FIRST, MQTT_PUBWAIT);
    break;
  }
  default:
    DEBUGASSERT(NULL); /* illegal state */
    result = CURLE_WEIRD_SERVER_REPLY;
    goto end;
  }
  end:
  return result;
}

static CURLcode mqtt_do(struct connectdata *conn, bool *done)
{
  CURLcode result = CURLE_OK;
  struct Curl_easy *data = conn->data;

  *done = FALSE; /* unconditionally */

  result = mqtt_connect(conn);
  if(result) {
    failf(data, "Error %d sending MQTT CONN request", result);
    return result;
  }
  mqstate(conn, MQTT_FIRST, MQTT_CONNACK);
  return CURLE_OK;
}

static CURLcode mqtt_doing(struct connectdata *conn, bool *done)
{
  CURLcode result = CURLE_OK;
  struct mqtt_conn *mqtt = &conn->proto.mqtt;
  struct Curl_easy *data = conn->data;
  struct MQTT *mq = data->req.protop;
  ssize_t nread;
  curl_socket_t sockfd = conn->sock[FIRSTSOCKET];
  unsigned char *pkt = (unsigned char *)data->state.buffer;
  unsigned char byte;

  *done = FALSE;

  if(mq->nsend) {
    /* send the remainder of an outgoing packet */
    char *ptr = mq->sendleftovers;
    result = mqtt_send(conn, mq->sendleftovers, mq->nsend);
    free(ptr);
    if(result)
      return result;
  }

  infof(data, "mqtt_doing: state [%d]\n", (int) mqtt->state);
  switch(mqtt->state) {
  case MQTT_FIRST:
    /* Read the initial byte only */
    result = Curl_read(conn, sockfd, (char *)&mq->firstbyte, 1, &nread);
    if(result)
      break;
    if(data->set.verbose)
      Curl_debug(data, CURLINFO_HEADER_IN, (char *)&mq->firstbyte, 1);
    /* remember the first byte */
    mq->npacket = 0;
    mqstate(conn, MQTT_REMAINING_LENGTH, MQTT_NOSTATE);
    /* FALLTHROUGH */
  case MQTT_REMAINING_LENGTH:
    do {
      result = Curl_read(conn, sockfd, (char *)&byte, 1, &nread);
      if(result)
        break;
      if(data->set.verbose)
        Curl_debug(data, CURLINFO_HEADER_IN, (char *)&byte, 1);
      pkt[mq->npacket++] = byte;
    } while((byte & 0x80) && (mq->npacket < 4));
    if(result)
      break;
    mq->remaining_length = mqtt_decode_len(&pkt[0], mq->npacket, NULL);
    mq->npacket = 0;
    if(mq->remaining_length) {
      mqstate(conn, mqtt->nextstate, MQTT_NOSTATE);
      break;
    }
    mqstate(conn, MQTT_FIRST, MQTT_FIRST);

    if(mq->firstbyte == MQTT_MSG_DISCONNECT) {
      infof(data, "Got DISCONNECT\n");
      *done = TRUE;
    }
    break;
  case MQTT_CONNACK:
    result = mqtt_verify_connack(conn);
    if(result)
      break;

    if(conn->data->state.httpreq == HTTPREQ_POST) {
      result = mqtt_publish(conn);
      if(!result) {
        result = mqtt_disconnect(conn);
        *done = TRUE;
      }
      mqtt->nextstate = MQTT_FIRST;
    }
    else {
      result = mqtt_subscribe(conn);
      if(!result) {
        mqstate(conn, MQTT_FIRST, MQTT_SUBACK);
      }
    }
    break;

  case MQTT_SUBACK:
  case MQTT_PUBWAIT:
  case MQTT_PUB_REMAIN:
    result = mqtt_read_publish(conn, done);
    break;

  default:
    failf(conn->data, "State not handled yet");
    *done = TRUE;
    break;
  }

  if(result == CURLE_AGAIN)
    result = CURLE_OK;
  return result;
}

#endif /* CURL_ENABLE_MQTT */