aboutsummaryrefslogtreecommitdiff
path: root/src/or/connection_or.c
blob: 78a99961500150f0558dd6940591f0e61541d946 (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
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
/* Copyright 2001 Matej Pfajfar.
 * Copyright 2001-2004 Roger Dingledine.
 * Copyright 2004-2005 Roger Dingledine, Nick Mathewson. */
/* See LICENSE for licensing information */
/* $Id$ */
const char connection_or_c_id[] = "$Id$";

/**
 * \file connection_or.c
 * \brief Functions to handle OR connections, TLS handshaking, and
 * cells on the network.
 **/

#include "or.h"

/** How much clock skew do we tolerate when checking certificates for
 * known routers? (sec) */
#define TIGHT_CERT_ALLOW_SKEW (90*60)

static int connection_tls_finish_handshake(connection_t *conn);
static int connection_or_process_cells_from_inbuf(connection_t *conn);

/**************************************************************/

/** Map from identity digest of connected OR or desired OR to a connection_t
 * with that identity digest.  If there is more than one such connection_t,
 * they form a linked list, with next_with_same_id as the next pointer.*/
static digestmap_t *orconn_identity_map = NULL;

/** If conn is listed in orconn_identity_map, remove it, and clear
 * conn->identity_digest. */
void
connection_or_remove_from_identity_map(connection_t *conn)
{
  connection_t *tmp;
  tor_assert(conn);
  tor_assert(conn->type == CONN_TYPE_OR);
  if (!orconn_identity_map)
    return;
  tmp = digestmap_get(orconn_identity_map, conn->identity_digest);
  if (!tmp)
    return;
  if (conn == tmp) {
    if (conn->next_with_same_id)
      digestmap_set(orconn_identity_map, conn->identity_digest,
                    conn->next_with_same_id);
    else
      digestmap_remove(orconn_identity_map, conn->identity_digest);
  } else {
    while (tmp->next_with_same_id) {
      if (tmp->next_with_same_id == conn) {
        tmp->next_with_same_id = conn->next_with_same_id;
        break;
      }
      tmp = tmp->next_with_same_id;
    }
  }
  memset(conn->identity_digest, 0, DIGEST_LEN);
  conn->next_with_same_id = NULL;
}

/** Remove all entries from the identity-to-orconn map, and clear
 * all identities in OR conns.*/
void
connection_or_clear_identity_map(void)
{
  int i, n;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i = 0; i < n; ++i) {
    connection_t* conn = carray[i];
    if (conn->type == CONN_TYPE_OR) {
      memset(conn->identity_digest, 0, DIGEST_LEN);
      conn->next_with_same_id = NULL;
    }
  }

  digestmap_free(orconn_identity_map, NULL);
  orconn_identity_map = NULL;
}

/** Change conn->identity_digest to digest, and add conn into
 * orconn_digest_map. */
static void
connection_or_set_identity_digest(connection_t *conn, const char *digest)
{
  connection_t *tmp;
  tor_assert(conn);
  tor_assert(conn->type == CONN_TYPE_OR);
  tor_assert(digest);

  if (!orconn_identity_map)
    orconn_identity_map = digestmap_new();
  if (!memcmp(conn->identity_digest, digest, DIGEST_LEN))
    return;
  if (tor_digest_is_zero(conn->identity_digest))
    connection_or_remove_from_identity_map(conn);

  memcpy(conn->identity_digest, digest, DIGEST_LEN);
  tmp = digestmap_set(orconn_identity_map, digest, conn);
  conn->next_with_same_id = tmp;

  /* Checking code; remove once I'm sure this works. XXXX*/
  for (; tmp; tmp = tmp->next_with_same_id) {
    tor_assert(!memcmp(tmp->identity_digest, digest, DIGEST_LEN));
    tor_assert(tmp != conn);
  }
}

/** Pack the cell_t host-order structure <b>src</b> into network-order
 * in the buffer <b>dest</b>. See tor-spec.txt for details about the
 * wire format.
 */
static void
cell_pack(char *dest, const cell_t *src)
{
  *(uint16_t*)dest    = htons(src->circ_id);
  *(uint8_t*)(dest+2) = src->command;
  memcpy(dest+3, src->payload, CELL_PAYLOAD_SIZE);
}

/** Unpack the network-order buffer <b>src</b> into a host-order
 * cell_t structure <b>dest</b>.
 */
static void
cell_unpack(cell_t *dest, const char *src)
{
  dest->circ_id = ntohs(*(uint16_t*)(src));
  dest->command = *(uint8_t*)(src+2);
  memcpy(dest->payload, src+3, CELL_PAYLOAD_SIZE);
}

int
connection_or_reached_eof(connection_t *conn)
{
  info(LD_OR,"OR connection reached EOF. Closing.");
  connection_mark_for_close(conn);
  return 0;
}

/** Read conn's inbuf. If the http response from the proxy is all
 * here, make sure it's good news, and begin the tls handshake. If
 * it's bad news, close the connection and return -1. Else return 0
 * and hope for better luck next time.
 */
static int
connection_or_read_proxy_response(connection_t *conn)
{
  char *headers;
  char *reason=NULL;
  int status_code;
  time_t date_header;
  int compression;

  switch (fetch_from_buf_http(conn->inbuf,
                              &headers, MAX_HEADERS_SIZE,
                              NULL, NULL, 10000, 0)) {
    case -1: /* overflow */
      warn(LD_PROTOCOL,"Your https proxy sent back an oversized response. Closing.");
      return -1;
    case 0:
      info(LD_OR,"https proxy response not all here yet. Waiting.");
      return 0;
    /* case 1, fall through */
  }

  if (parse_http_response(headers, &status_code, &date_header,
                          &compression, &reason) < 0) {
    warn(LD_OR,"Unparseable headers from proxy (connecting to '%s'). Closing.",
         conn->address);
    tor_free(headers);
    return -1;
  }
  if (!reason) reason = tor_strdup("[no reason given]");

  if (status_code == 200) {
    info(LD_OR,
         "HTTPS connect to '%s' successful! (200 \"%s\") Starting TLS.",
         conn->address, reason);
    tor_free(reason);
    if (connection_tls_start_handshake(conn, 0) < 0) {
      /* TLS handshaking error of some kind. */
      connection_mark_for_close(conn);

      return -1;
    }
    return 0;
  }
  /* else, bad news on the status code */
  warn(LD_OR,
      "The https proxy sent back an unexpected status code %d (\"%s\"). Closing.",
      status_code, reason);
  tor_free(reason);
  connection_mark_for_close(conn);
  return -1;
}

/** Handle any new bytes that have come in on connection <b>conn</b>.
 * If conn is in 'open' state, hand it to
 * connection_or_process_cells_from_inbuf()
 * (else do nothing).
 */
int
connection_or_process_inbuf(connection_t *conn)
{
  tor_assert(conn);
  tor_assert(conn->type == CONN_TYPE_OR);

  switch (conn->state) {
    case OR_CONN_STATE_PROXY_READING:
      return connection_or_read_proxy_response(conn);
    case OR_CONN_STATE_OPEN:
      return connection_or_process_cells_from_inbuf(conn);
    default:
      return 0; /* don't do anything */
  }
}

/** Connection <b>conn</b> has finished writing and has no bytes left on
 * its outbuf.
 *
 * Otherwise it's in state "open": stop writing and return.
 *
 * If <b>conn</b> is broken, mark it for close and return -1, else
 * return 0.
 */
int
connection_or_finished_flushing(connection_t *conn)
{
  tor_assert(conn);
  tor_assert(conn->type == CONN_TYPE_OR);

  assert_connection_ok(conn,0);

  switch (conn->state) {
    case OR_CONN_STATE_PROXY_FLUSHING:
      debug(LD_OR,"finished sending CONNECT to proxy.");
      conn->state = OR_CONN_STATE_PROXY_READING;
      connection_stop_writing(conn);
      break;
    case OR_CONN_STATE_OPEN:
      connection_stop_writing(conn);
      break;
    default:
      err(LD_BUG,"BUG: called in unexpected state %d.", conn->state);
      tor_fragile_assert();
      return -1;
  }
  return 0;
}

/** Connected handler for OR connections: begin the TLS handshake.
 */
int
connection_or_finished_connecting(connection_t *conn)
{
  tor_assert(conn);
  tor_assert(conn->type == CONN_TYPE_OR);
  tor_assert(conn->state == OR_CONN_STATE_CONNECTING);

  debug(LD_OR,"OR connect() to router at %s:%u finished.",
         conn->address,conn->port);

  if (get_options()->HttpsProxy) {
    char buf[1024];
    char addrbuf[INET_NTOA_BUF_LEN];
    struct in_addr in;
    char *base64_authenticator=NULL;
    const char *authenticator = get_options()->HttpsProxyAuthenticator;

    in.s_addr = htonl(conn->addr);
    tor_inet_ntoa(&in, addrbuf, sizeof(addrbuf));

    if (authenticator) {
      base64_authenticator = alloc_http_authenticator(authenticator);
      if (!base64_authenticator)
        warn(LD_OR, "Encoding https authenticator failed");
    }
    if (base64_authenticator) {
      tor_snprintf(buf, sizeof(buf), "CONNECT %s:%d HTTP/1.1\r\n"
                   "Proxy-Authorization: Basic %s\r\n\r\n", addrbuf,
                   conn->port, base64_authenticator);
      tor_free(base64_authenticator);
    } else {
      tor_snprintf(buf, sizeof(buf), "CONNECT %s:%d HTTP/1.0\r\n\r\n",
                   addrbuf, conn->port);
    }
    connection_write_to_buf(buf, strlen(buf), conn);
    conn->state = OR_CONN_STATE_PROXY_FLUSHING;
    return 0;
  }

  if (connection_tls_start_handshake(conn, 0) < 0) {
    /* TLS handshaking error of some kind. */
    connection_mark_for_close(conn);
    return -1;
  }
  return 0;
}

/** Initialize <b>conn</b> to include all the relevant data from <b>router</b>.
 * This function is called either from connection_or_connect(), if
 * we initiated the connect, or from connection_tls_finish_handshake()
 * if the other side initiated it.
 */
static void
connection_or_init_conn_from_router(connection_t *conn, routerinfo_t *router)
{
  or_options_t *options = get_options();

  conn->addr = router->addr;
  conn->port = router->or_port;
  conn->receiver_bucket = conn->bandwidth = (int)options->BandwidthBurst;
  conn->identity_pkey = crypto_pk_dup_key(router->identity_pkey);
  connection_or_set_identity_digest(conn, router->cache_info.identity_digest);
  conn->nickname = tor_strdup(router->nickname);
  tor_free(conn->address);
  conn->address = tor_strdup(router->address);
}

/** If we don't necessarily know the router we're connecting to, but we
 * have an addr/port/id_digest, then fill in as much as we can. Start
 * by checking to see if this describes a router we know. */
static void
connection_or_init_conn_from_address(connection_t *conn,
                                     uint32_t addr, uint16_t port,
                                     const char *id_digest)
{
  const char *n;
  or_options_t *options = get_options();
  routerinfo_t *r = router_get_by_digest(id_digest);
  if (r) {
    connection_or_init_conn_from_router(conn,r);
    return;
  }
  conn->addr = addr;
  conn->port = port;
  /* This next part isn't really right, but it's good enough for now. */
  conn->receiver_bucket = conn->bandwidth = (int)options->BandwidthBurst;
  connection_or_set_identity_digest(conn, id_digest);
  /* If we're an authoritative directory server, we may know a
   * nickname for this router. */
  n = dirserv_get_nickname_by_digest(id_digest);
  if (n) {
    conn->nickname = tor_strdup(n);
  } else {
    conn->nickname = tor_malloc(HEX_DIGEST_LEN+2);
    conn->nickname[0] = '$';
    base16_encode(conn->nickname+1, HEX_DIGEST_LEN+1,
                  conn->identity_digest, DIGEST_LEN);
  }
  tor_free(conn->address);
  conn->address = tor_dup_addr(addr);
}

/** Return the best connection of type OR with the
 * digest <b>digest</b> that we have, or NULL if we have none.
 *
 * 1) Don't return it if it's marked for close.
 * 2) If there are any open conns, ignore non-open conns.
 * 3) If there are any non-obsolete conns, ignore obsolete conns.
 * 4) Then if there are any non-empty conns, ignore empty conns.
 * 5) Of the remaining conns, prefer newer conns.
 */
connection_t *
connection_or_get_by_identity_digest(const char *digest)
{
  int newer;
  connection_t *conn, *best=NULL;

  if (!orconn_identity_map)
    return NULL;

  conn = digestmap_get(orconn_identity_map, digest);

  for (; conn; conn = conn->next_with_same_id) {
    tor_assert(conn->magic == CONNECTION_MAGIC);
    tor_assert(conn->type == CONN_TYPE_OR);
    tor_assert(!memcmp(conn->identity_digest, digest, DIGEST_LEN));
    if (conn->marked_for_close)
      continue;
    if (!best) {
      best = conn; /* whatever it is, it's better than nothing. */
      continue;
    }
    if (best->state == OR_CONN_STATE_OPEN &&
        conn->state != OR_CONN_STATE_OPEN)
      continue; /* avoid non-open conns if we can */
    newer = best->timestamp_created < conn->timestamp_created;
    if (conn->is_obsolete && (!best->is_obsolete || !newer))
      continue; /* we have something, and it's better than this. */
    if (best->n_circuits && !conn->n_circuits)
      continue; /* prefer conns with circuits on them */
    if (newer)
      best = conn; /* lastly, prefer newer conns */
  }
  return best;
}

/** Launch a new OR connection to <b>addr</b>:<b>port</b> and expect to
 * handshake with an OR with identity digest <b>id_digest</b>.
 *
 * If <b>id_digest</b> is me, do nothing. If we're already connected to it,
 * return that connection. If the connect() is in progress, set the
 * new conn's state to 'connecting' and return it. If connect() succeeds,
 * call connection_tls_start_handshake() on it.
 *
 * This function is called from router_retry_connections(), for
 * ORs connecting to ORs, and circuit_establish_circuit(), for
 * OPs connecting to ORs.
 *
 * Return the launched conn, or NULL if it failed.
 */
connection_t *
connection_or_connect(uint32_t addr, uint16_t port, const char *id_digest)
{
  connection_t *conn;
  routerinfo_t *me;
  or_options_t *options = get_options();

  tor_assert(id_digest);

  if (server_mode(options) && (me=router_get_my_routerinfo()) &&
      router_digest_is_me(id_digest)) {
    info(LD_PROTOCOL,"Client asked me to connect to myself. Refusing.");
    return NULL;
  }

  conn = connection_new(CONN_TYPE_OR);

  /* set up conn so it's got all the data we need to remember */
  connection_or_init_conn_from_address(conn, addr, port, id_digest);
  conn->state = OR_CONN_STATE_CONNECTING;
  control_event_or_conn_status(conn, OR_CONN_EVENT_LAUNCHED);

  if (options->HttpsProxy) {
    /* we shouldn't connect directly. use the https proxy instead. */
    addr = options->HttpsProxyAddr;
    port = options->HttpsProxyPort;
  }

  switch (connection_connect(conn, conn->address, addr, port)) {
    case -1:
      if (!options->HttpsProxy)
        router_mark_as_down(conn->identity_digest);
      helper_node_set_status(conn->identity_digest, 0);
      control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED);
      connection_free(conn);
      return NULL;
    case 0:
      connection_watch_events(conn, EV_READ | EV_WRITE);
      /* writable indicates finish, readable indicates broken link,
         error indicates broken link on windows */
      return conn;
    /* case 1: fall through */
  }

  if (connection_or_finished_connecting(conn) < 0) {
    /* already marked for close */
    return NULL;
  }
  return conn;
}

/** Begin the tls handshake with <b>conn</b>. <b>receiving</b> is 0 if
 * we initiated the connection, else it's 1.
 *
 * Assign a new tls object to conn->tls, begin reading on <b>conn</b>, and pass
 * <b>conn</b> to connection_tls_continue_handshake().
 *
 * Return -1 if <b>conn</b> is broken, else return 0.
 */
int
connection_tls_start_handshake(connection_t *conn, int receiving)
{
  conn->state = OR_CONN_STATE_HANDSHAKING;
  conn->tls = tor_tls_new(conn->s, receiving, 0);
  if (!conn->tls) {
    warn(LD_BUG,"tor_tls_new failed. Closing.");
    return -1;
  }
  connection_start_reading(conn);
  debug(LD_OR,"starting TLS handshake on fd %d", conn->s);
  if (connection_tls_continue_handshake(conn) < 0) {
    return -1;
  }
  return 0;
}

/** Move forward with the tls handshake. If it finishes, hand
 * <b>conn</b> to connection_tls_finish_handshake().
 *
 * Return -1 if <b>conn</b> is broken, else return 0.
 */
int
connection_tls_continue_handshake(connection_t *conn)
{
  check_no_tls_errors();
  switch (tor_tls_handshake(conn->tls)) {
    case TOR_TLS_ERROR:
    case TOR_TLS_CLOSE:
      info(LD_OR,"tls error. breaking connection.");
      return -1;
    case TOR_TLS_DONE:
     return connection_tls_finish_handshake(conn);
    case TOR_TLS_WANTWRITE:
      connection_start_writing(conn);
      debug(LD_OR,"wanted write");
      return 0;
    case TOR_TLS_WANTREAD: /* handshaking conns are *always* reading */
      debug(LD_OR,"wanted read");
      return 0;
  }
  return 0;
}

/** Return 1 if we initiated this connection, or 0 if it started
 * out as an incoming connection.
 *
 * This is implemented for now by checking to see if
 * conn-\>identity_digest is set or not. Perhaps we should add a flag
 * one day so we're clearer.
 */
int
connection_or_nonopen_was_started_here(connection_t *conn)
{
  tor_assert(conn->type == CONN_TYPE_OR);

  if (tor_digest_is_zero(conn->identity_digest))
    return 0;
  else
    return 1;
}

/** Conn just completed its handshake. Return 0 if all is well, and
 * return -1 if he is lying, broken, or otherwise something is wrong.
 *
 * Make sure he sent a correctly formed certificate. If it has a
 * recognized (approved) nickname, make sure his identity key matches
 * it. If I initiated the connection, make sure it's the right guy.
 *
 * If we return 0, write a hash of the identity key into digest_rcvd,
 * which must have DIGEST_LEN space in it. (If we return -1 this
 * buffer is undefined.)
 *
 * As side effects,
 * 1) Set conn->circ_id_type according to tor-spec.txt
 * 2) If we're an authdirserver and we initiated the connection: drop all
 *    descriptors that claim to be on that IP/port but that aren't
 *    this guy; and note that this guy is reachable.
 */
static int
connection_or_check_valid_handshake(connection_t *conn, char *digest_rcvd)
{
  routerinfo_t *router;
  crypto_pk_env_t *identity_rcvd=NULL;
  char nickname[MAX_NICKNAME_LEN+1];
  or_options_t *options = get_options();
  int severity = server_mode(options) ? LOG_PROTOCOL_WARN : LOG_WARN;

  check_no_tls_errors();
  if (! tor_tls_peer_has_cert(conn->tls)) {
    info(LD_PROTOCOL,"Peer didn't send a cert! Closing.");
    return -1;
  }
  check_no_tls_errors();
  if (tor_tls_get_peer_cert_nickname(conn->tls, nickname, sizeof(nickname))) {
    log_fn(severity,LD_PROTOCOL,"Other side (%s:%d) has a cert without a valid nickname. Closing.",
           conn->address, conn->port);
    return -1;
  }
  check_no_tls_errors();
  debug(LD_OR, "Other side (%s:%d) claims to be router '%s'",
         conn->address, conn->port, nickname);

  if (tor_tls_verify(severity, conn->tls, &identity_rcvd) < 0) {
    log_fn(severity,LD_OR,"Other side, which claims to be router '%s' (%s:%d), has a cert but it's invalid. Closing.",
           nickname, conn->address, conn->port);
    return -1;
  }
  check_no_tls_errors();
  debug(LD_OR,"The router's cert is valid.");
  crypto_pk_get_digest(identity_rcvd, digest_rcvd);

  if (crypto_pk_cmp_keys(get_identity_key(), identity_rcvd)<0) {
    conn->circ_id_type = CIRC_ID_TYPE_LOWER;
  } else {
    conn->circ_id_type = CIRC_ID_TYPE_HIGHER;
  }
  crypto_free_pk_env(identity_rcvd);

  router = router_get_by_nickname(nickname, 0);
  if (router && /* we know this nickname */
      router->is_named && /* make sure it's the right guy */
      memcmp(digest_rcvd, router->cache_info.identity_digest,DIGEST_LEN) !=0) {
    log_fn(severity, LD_OR,
           "Identity key not as expected for router claiming to be '%s' (%s:%d)",
           nickname, conn->address, conn->port);
    return -1;
  }

  if (connection_or_nonopen_was_started_here(conn)) {
    int as_advertised = 1;
    if (memcmp(digest_rcvd, conn->identity_digest, DIGEST_LEN)) {
      /* I was aiming for a particular digest. I didn't get it! */
      char seen[HEX_DIGEST_LEN+1];
      char expected[HEX_DIGEST_LEN+1];
      base16_encode(seen, sizeof(seen), digest_rcvd, DIGEST_LEN);
      base16_encode(expected, sizeof(expected), conn->identity_digest, DIGEST_LEN);
      log_fn(severity, LD_OR,
             "Identity key not as expected for router at %s:%d: wanted %s but got %s",
             conn->address, conn->port, expected, seen);
      helper_node_set_status(conn->identity_digest, 0);
      control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED);
      as_advertised = 0;
    }
    if (authdir_mode(options)) {
      /* We initiated this connection to address:port.  Drop all routers
       * with the same address:port and a different key or nickname.
       */
      dirserv_orconn_tls_done(conn->address, conn->port,
                              digest_rcvd, nickname, as_advertised);
    }
    if (!as_advertised)
      return -1;
  }
  return 0;
}

/** The tls handshake is finished.
 *
 * Make sure we are happy with the person we just handshaked with.
 *
 * If he initiated the connection, make sure he's not already connected,
 * then initialize conn from the information in router.
 *
 * If I'm not a server, set bandwidth to the default OP bandwidth.
 *
 * If all is successful, call circuit_n_conn_done() to handle events
 * that have been pending on the tls handshake completion. Also set the
 * directory to be dirty (only matters if I'm an authdirserver).
 */
static int
connection_tls_finish_handshake(connection_t *conn)
{
  char digest_rcvd[DIGEST_LEN];

  debug(LD_OR,"tls handshake done. verifying.");
  if (connection_or_check_valid_handshake(conn, digest_rcvd) < 0)
    return -1;

  if (!connection_or_nonopen_was_started_here(conn)) {
#if 0
    connection_t *c;
    if ((c=connection_or_get_by_identity_digest(digest_rcvd))) {
      debug(LD_OR,"Router '%s' is already connected on fd %d. Dropping fd %d.",
             c->nickname, c->s, conn->s);
      return -1;
    }
#endif
    connection_or_init_conn_from_address(conn,conn->addr,conn->port,digest_rcvd);
  }

  if (!server_mode(get_options())) { /* If I'm an OP... */
    conn->receiver_bucket = conn->bandwidth = DEFAULT_BANDWIDTH_OP;
  }

  directory_set_dirty();
  conn->state = OR_CONN_STATE_OPEN;
  connection_watch_events(conn, EV_READ);
  circuit_n_conn_done(conn, 1); /* send the pending creates, if any. */
  rep_hist_note_connect_succeeded(conn->identity_digest, time(NULL));
  helper_node_set_status(conn->identity_digest, 1);
  control_event_or_conn_status(conn, OR_CONN_EVENT_CONNECTED);
  return 0;
}

/** Pack <b>cell</b> into wire-format, and write it onto <b>conn</b>'s
 * outbuf.
 *
 * (Commented out) If it's an OR conn, and an entire TLS record is
 * ready, then try to flush the record now.
 */
void
connection_or_write_cell_to_buf(const cell_t *cell, connection_t *conn)
{
  char networkcell[CELL_NETWORK_SIZE];
  char *n = networkcell;

  tor_assert(cell);
  tor_assert(conn);
  tor_assert(connection_speaks_cells(conn));

  cell_pack(n, cell);

  connection_write_to_buf(n, CELL_NETWORK_SIZE, conn);

#define MIN_TLS_FLUSHLEN 15872
/* openssl tls record size is 16383, this is close. The goal here is to
 * push data out as soon as we know there's enough for a tls record, so
 * during periods of high load we won't read the entire megabyte from
 * input before pushing any data out. It also has the feature of not
 * growing huge outbufs unless something is slow. */
  if (conn->outbuf_flushlen-CELL_NETWORK_SIZE < MIN_TLS_FLUSHLEN &&
      conn->outbuf_flushlen >= MIN_TLS_FLUSHLEN) {
    int extra = conn->outbuf_flushlen - MIN_TLS_FLUSHLEN;
    conn->outbuf_flushlen = MIN_TLS_FLUSHLEN;
    if (connection_handle_write(conn) < 0) {
      if (!conn->marked_for_close) {
        /* this connection is broken. remove it. */
        warn(LD_BUG,"Bug: unhandled error on write for OR conn (fd %d); removing",
               conn->s);
        tor_fragile_assert();
        conn->has_sent_end = 1; /* otherwise we cry wolf about duplicate close */
        /* XXX do we need a close-immediate here, so we don't try to flush? */
        connection_mark_for_close(conn);
      }
      return;
    }
    if (extra) {
      conn->outbuf_flushlen += extra;
      connection_start_writing(conn);
    }
  }
}

/** Process cells from <b>conn</b>'s inbuf.
 *
 * Loop: while inbuf contains a cell, pull it off the inbuf, unpack it,
 * and hand it to command_process_cell().
 *
 * Always return 0.
 */
static int
connection_or_process_cells_from_inbuf(connection_t *conn)
{
  char buf[CELL_NETWORK_SIZE];
  cell_t cell;

loop:
  debug(LD_OR,"%d: starting, inbuf_datalen %d (%d pending in tls object).",
         conn->s,(int)buf_datalen(conn->inbuf),tor_tls_get_pending_bytes(conn->tls));
  if (buf_datalen(conn->inbuf) < CELL_NETWORK_SIZE) /* entire response available? */
    return 0; /* not yet */

  connection_fetch_from_buf(buf, CELL_NETWORK_SIZE, conn);

  /* retrieve cell info from buf (create the host-order struct from the
   * network-order string) */
  cell_unpack(&cell, buf);

  command_process_cell(&cell, conn);

  goto loop; /* process the remainder of the buffer */
}