aboutsummaryrefslogtreecommitdiff
path: root/src/or/connection.c
blob: cf58eaf369d121a4430b0e14ca187f9f0951e8b7 (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
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
/* 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_c_id[] = "$Id$";

/**
 * \file connection.c
 * \brief General high-level functions to handle reading and writing
 * on connections.
 **/

#include "or.h"

static connection_t *connection_create_listener(const char *listenaddress,
                                                uint16_t listenport, int type);
static int connection_init_accepted_conn(connection_t *conn);
static int connection_handle_listener_read(connection_t *conn, int new_type);
static int connection_receiver_bucket_should_increase(connection_t *conn);
static int connection_finished_flushing(connection_t *conn);
static int connection_finished_connecting(connection_t *conn);
static int connection_reached_eof(connection_t *conn);
static int connection_read_to_buf(connection_t *conn, int *max_to_read);
static int connection_process_inbuf(connection_t *conn, int package_partial);
static void client_check_address_changed(int sock);

static uint32_t last_interface_ip = 0;
static smartlist_t *outgoing_addrs = NULL;

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

/**
 * Return the human-readable name for the connection type <b>type</b>
 */
const char *
conn_type_to_string(int type)
{
  static char buf[64];
  switch (type) {
    case CONN_TYPE_OR_LISTENER: return "OR listener";
    case CONN_TYPE_OR: return "OR";
    case CONN_TYPE_EXIT: return "Exit";
    case CONN_TYPE_AP_LISTENER: return "Socks listener";
    case CONN_TYPE_AP: return "Socks";
    case CONN_TYPE_DIR_LISTENER: return "Directory listener";
    case CONN_TYPE_DIR: return "Directory";
    case CONN_TYPE_DNSWORKER: return "DNS worker";
    case CONN_TYPE_CPUWORKER: return "CPU worker";
    case CONN_TYPE_CONTROL_LISTENER: return "Control listener";
    case CONN_TYPE_CONTROL: return "Control";
    default:
      warn(LD_BUG, "Bug: unknown connection type %d", type);
      tor_snprintf(buf, sizeof(buf), "unknown [%d]", type);
      return buf;
  }
}

/**
 * Return the human-readable name for the connection state <b>state</b>
 * for the connection type <b>type</b>
 */
const char *
conn_state_to_string(int type, int state)
{
  static char buf[96];
  switch (type) {
    case CONN_TYPE_OR_LISTENER:
    case CONN_TYPE_AP_LISTENER:
    case CONN_TYPE_DIR_LISTENER:
    case CONN_TYPE_CONTROL_LISTENER:
      if (state == LISTENER_STATE_READY)
        return "ready";
      break;
    case CONN_TYPE_OR:
      switch (state) {
        case OR_CONN_STATE_CONNECTING: return "connect()ing";
        case OR_CONN_STATE_PROXY_FLUSHING: return "proxy flushing";
        case OR_CONN_STATE_PROXY_READING: return "proxy reading";
        case OR_CONN_STATE_HANDSHAKING: return "proxy reading";
        case OR_CONN_STATE_OPEN: return "open";
      }
      break;
    case CONN_TYPE_EXIT:
      switch (state) {
        case EXIT_CONN_STATE_RESOLVING: return "waiting for dest info";
        case EXIT_CONN_STATE_CONNECTING: return "connecting";
        case EXIT_CONN_STATE_OPEN: return "open";
        case EXIT_CONN_STATE_RESOLVEFAILED: return "resolve failed";
      }
      break;
    case CONN_TYPE_AP:
      switch (state) {
        case AP_CONN_STATE_SOCKS_WAIT: return "waiting for dest info";
        case AP_CONN_STATE_RENDDESC_WAIT: return "waiting for rendezvous desc";
        case AP_CONN_STATE_CONTROLLER_WAIT: return "waiting for controller";
        case AP_CONN_STATE_CIRCUIT_WAIT: return "waiting for safe circuit";
        case AP_CONN_STATE_CONNECT_WAIT: return "waiting for connect";
        case AP_CONN_STATE_RESOLVE_WAIT: return "waiting for resolve";
        case AP_CONN_STATE_OPEN: return "open";
      }
      break;
    case CONN_TYPE_DIR:
      switch (state) {
        case DIR_CONN_STATE_CONNECTING: return "connecting";
        case DIR_CONN_STATE_CLIENT_SENDING: return "client sending";
        case DIR_CONN_STATE_CLIENT_READING: return "cleint reading";
        case DIR_CONN_STATE_SERVER_COMMAND_WAIT: return "waiting for command";
        case DIR_CONN_STATE_SERVER_WRITING: return "writing";
      }
      break;
    case CONN_TYPE_DNSWORKER:
      switch (state) {
        case DNSWORKER_STATE_IDLE: return "idle";
        case DNSWORKER_STATE_BUSY: return "busy";
      }
      break;
    case CONN_TYPE_CPUWORKER:
      switch (state) {
        case CPUWORKER_STATE_IDLE: return "idle";
        case CPUWORKER_STATE_BUSY_ONION: return "busy with onion";
      }
      break;
    case CONN_TYPE_CONTROL:
      switch (state) {
        case CONTROL_CONN_STATE_OPEN_V0: return "open (protocol v0)";
        case CONTROL_CONN_STATE_OPEN_V1: return "open (protocol v1)";
        case CONTROL_CONN_STATE_NEEDAUTH_V0:
          return "waiting for authentication (protocol unknown)";
        case CONTROL_CONN_STATE_NEEDAUTH_V1:
          return "waiting for authentication (protocol v1)";
      }
      break;
  }

  warn(LD_BUG, "Bug: unknown connection state %d (type %d)", state, type);
  tor_snprintf(buf, sizeof(buf),
               "unknown state [%d] on unknown [%s] connection",
               state, conn_type_to_string(type));
  return buf;
}

/** Allocate space for a new connection_t. This function just initializes
 * conn; you must call connection_add() to link it into the main array.
 *
 * Set conn-\>type to <b>type</b>. Set conn-\>s and conn-\>poll_index to
 * -1 to signify they are not yet assigned.
 *
 * If conn is not a listener type, allocate buffers for it. If it's
 * an AP type, allocate space to store the socks_request.
 *
 * Assign a pseudorandom next_circ_id between 0 and 2**15.
 *
 * Initialize conn's timestamps to now.
 */
connection_t *
connection_new(int type)
{
  static uint32_t n_connections_allocated = 0;
  connection_t *conn;
  time_t now = time(NULL);

  conn = tor_malloc_zero(sizeof(connection_t));
  conn->magic = CONNECTION_MAGIC;
  conn->s = -1; /* give it a default of 'not used' */
  conn->poll_index = -1; /* also default to 'not used' */
  conn->global_identifier = n_connections_allocated++;

  conn->type = type;
  if (!connection_is_listener(conn)) { /* listeners never use their buf */
    conn->inbuf = buf_new();
    conn->outbuf = buf_new();
  }
  if (type == CONN_TYPE_AP) {
    conn->socks_request = tor_malloc_zero(sizeof(socks_request_t));
  }

  conn->next_circ_id = crypto_rand_int(1<<15);

  conn->timestamp_created = now;
  conn->timestamp_lastread = now;
  conn->timestamp_lastwritten = now;

  return conn;
}

/** Tell libevent that we don't care about <b>conn</b> any more. */
void
connection_unregister(connection_t *conn)
{
  if (conn->read_event) {
    if (event_del(conn->read_event))
      warn(LD_BUG, "Error removing read event for %d", conn->s);
    tor_free(conn->read_event);
  }
  if (conn->write_event) {
    if (event_del(conn->write_event))
      warn(LD_BUG, "Error removing write event for %d", conn->s);
    tor_free(conn->write_event);
  }
}

/** Deallocate memory used by <b>conn</b>. Deallocate its buffers if necessary,
 * close its socket if necessary, and mark the directory as dirty if <b>conn</b>
 * is an OR or OP connection.
 */
static void
_connection_free(connection_t *conn)
{
  tor_assert(conn->magic == CONNECTION_MAGIC);

  if (!connection_is_listener(conn)) {
    buf_free(conn->inbuf);
    buf_free(conn->outbuf);
  }
  tor_free(conn->address);
  tor_free(conn->chosen_exit_name);

  if (connection_speaks_cells(conn)) {
    if (conn->tls) {
      tor_tls_free(conn->tls);
      conn->tls = NULL;
    }
  }

  if (conn->identity_pkey)
    crypto_free_pk_env(conn->identity_pkey);
  tor_free(conn->nickname);
  tor_free(conn->socks_request);
  tor_free(conn->incoming_cmd);
  tor_free(conn->read_event); /* Probably already freed by connection_free. */
  tor_free(conn->write_event); /* Probably already freed by connection_free. */
  tor_free(conn->requested_resource);

  if (conn->s >= 0) {
    debug(LD_NET,"closing fd %d.",conn->s);
    tor_close_socket(conn->s);
  }

  if (conn->type == CONN_TYPE_OR && !tor_digest_is_zero(conn->identity_digest)) {
    warn(LD_BUG, "called on OR conn with non-zeroed idenity_digest");
    connection_or_remove_from_identity_map(conn);
  }

  memset(conn, 0xAA, sizeof(connection_t)); /* poison memory */
  tor_free(conn);
}

/** Make sure <b>conn</b> isn't in any of the global conn lists; then free it.
 */
void
connection_free(connection_t *conn)
{
  tor_assert(conn);
  tor_assert(!connection_is_on_closeable_list(conn));
  tor_assert(!connection_in_array(conn));
  if (connection_speaks_cells(conn)) {
    if (conn->state == OR_CONN_STATE_OPEN)
      directory_set_dirty();
    if (!tor_digest_is_zero(conn->identity_digest)) {
      connection_or_remove_from_identity_map(conn);
    }
  }
  if (conn->type == CONN_TYPE_CONTROL) {
    conn->event_mask = 0;
    control_update_global_event_mask();
  }
  connection_unregister(conn);
  _connection_free(conn);
}

/** Call _connection_free() on every connection in our array, and release all
 * storage helpd by connection.c. This is used by cpuworkers and dnsworkers
 * when they fork, so they don't keep resources held open (especially
 * sockets).
 *
 * Don't do the checks in connection_free(), because they will
 * fail.
 */
void
connection_free_all(void)
{
  int i, n;
  connection_t **carray;

  get_connection_array(&carray,&n);

  /* We don't want to log any messages to controllers. */
  for (i=0;i<n;i++)
    if (carray[i]->type == CONN_TYPE_CONTROL)
      carray[i]->event_mask = 0;
  control_update_global_event_mask();

  /* Unlink everything from the identity map. */
  connection_or_clear_identity_map();

  for (i=0;i<n;i++)
    _connection_free(carray[i]);

  if (outgoing_addrs) {
    SMARTLIST_FOREACH(outgoing_addrs, void*, addr, tor_free(addr));
    smartlist_free(outgoing_addrs);
    outgoing_addrs = NULL;
  }
}

/** Do any cleanup needed:
 *   - Directory conns that failed to fetch a rendezvous descriptor
 *     need to inform pending rendezvous streams.
 *   - OR conns need to call rep_hist_note_*() to record status.
 *   - AP conns need to send a socks reject if necessary.
 *   - Exit conns need to call connection_dns_remove() if necessary.
 *   - AP and Exit conns need to send an end cell if they can.
 *   - DNS conns need to fail any resolves that are pending on them.
 */
void
connection_about_to_close_connection(connection_t *conn)
{
  circuit_t *circ;

  assert(conn->marked_for_close);

  if (CONN_IS_EDGE(conn)) {
    if (!conn->has_sent_end) {
      warn(LD_BUG,
           "Harmless bug: Edge connection (marked at %s:%d) hasn't sent end yet?",
           conn->marked_for_close_file, conn->marked_for_close);
      tor_fragile_assert();
    }
  }

  switch (conn->type) {
    case CONN_TYPE_DIR:
      if (conn->state < DIR_CONN_STATE_CLIENT_FINISHED) {
        /* It's a directory connection and connecting or fetching
         * failed: forget about this router, and maybe try again. */
        connection_dir_request_failed(conn);
      }
      if (conn->purpose == DIR_PURPOSE_FETCH_RENDDESC)
        rend_client_desc_here(conn->rend_query); /* give it a try */
      break;
    case CONN_TYPE_OR:
      /* Remember why we're closing this connection. */
      if (conn->state != OR_CONN_STATE_OPEN) {
        if (connection_or_nonopen_was_started_here(conn)) {
          rep_hist_note_connect_failed(conn->identity_digest, time(NULL));
          helper_node_set_status(conn->identity_digest, 0);
          control_event_or_conn_status(conn, OR_CONN_EVENT_FAILED);
        }
      } else if (conn->hold_open_until_flushed) {
        /* XXXX009 We used to have an arg that told us whether we closed the
         * connection on purpose or not.  Can we use hold_open_until_flushed
         * instead?  We only set it when we are intentionally closing a
         * connection. -NM
         *
         * (Of course, now things we set to close which expire rather than
         * flushing still get noted as dead, not disconnected.  But this is an
         * improvement. -NM
         */
        rep_hist_note_disconnect(conn->identity_digest, time(NULL));
        control_event_or_conn_status(conn, OR_CONN_EVENT_CLOSED);
      } else if (conn->identity_digest) {
        rep_hist_note_connection_died(conn->identity_digest, time(NULL));
        control_event_or_conn_status(conn, OR_CONN_EVENT_CLOSED);
      }
      break;
    case CONN_TYPE_AP:
      if (conn->socks_request->has_finished == 0) {
        /* since conn gets removed right after this function finishes,
         * there's no point trying to send back a reply at this point. */
        warn(LD_BUG,"Bug: Closing stream (marked at %s:%d) without sending back a socks reply.",
             conn->marked_for_close_file, conn->marked_for_close);
      } else {
        control_event_stream_status(conn, STREAM_EVENT_CLOSED);
      }
      break;
    case CONN_TYPE_EXIT:
      if (conn->state == EXIT_CONN_STATE_RESOLVING) {
        circ = circuit_get_by_edge_conn(conn);
        if (circ)
          circuit_detach_stream(circ, conn);
        connection_dns_remove(conn);
      }
      break;
    case CONN_TYPE_DNSWORKER:
      if (conn->state == DNSWORKER_STATE_BUSY) {
        dns_cancel_pending_resolve(conn->address);
      }
      break;
  }
}

/** Close the underlying socket for <b>conn</b>, so we don't try to
 * flush it. Must be used in conjunction with (right before)
 * connection_mark_for_close().
 */
void
connection_close_immediate(connection_t *conn)
{
  assert_connection_ok(conn,0);
  if (conn->s < 0) {
    err(LD_BUG,"Bug: Attempt to close already-closed connection.");
    tor_fragile_assert();
    return;
  }
  if (conn->outbuf_flushlen) {
    info(LD_NET,"fd %d, type %s, state %s, %d bytes on outbuf.",
         conn->s, conn_type_to_string(conn->type),
         conn_state_to_string(conn->type, conn->state),
         (int)conn->outbuf_flushlen);
  }

  connection_unregister(conn);

  tor_close_socket(conn->s);
  conn->s = -1;
  if (!connection_is_listener(conn)) {
    buf_clear(conn->outbuf);
    conn->outbuf_flushlen = 0;
  }
}

/** Mark <b>conn</b> to be closed next time we loop through
 * conn_close_if_marked() in main.c. */
void
_connection_mark_for_close(connection_t *conn, int line, const char *file)
{
  assert_connection_ok(conn,0);
  tor_assert(line);
  tor_assert(file);

  if (conn->marked_for_close) {
    log(LOG_WARN,LD_BUG,"Duplicate call to connection_mark_for_close at %s:%d"
        " (first at %s:%d)", file, line, conn->marked_for_close_file,
        conn->marked_for_close);
    tor_fragile_assert();
    return;
  }

  conn->marked_for_close = line;
  conn->marked_for_close_file = file;
  add_connection_to_closeable_list(conn);

  /* in case we're going to be held-open-til-flushed, reset
   * the number of seconds since last successful write, so
   * we get our whole 15 seconds */
  conn->timestamp_lastwritten = time(NULL);
}

/** Find each connection that has hold_open_until_flushed set to
 * 1 but hasn't written in the past 15 seconds, and set
 * hold_open_until_flushed to 0. This means it will get cleaned
 * up in the next loop through close_if_marked() in main.c.
 */
void
connection_expire_held_open(void)
{
  connection_t **carray, *conn;
  int n, i;
  time_t now;

  now = time(NULL);

  get_connection_array(&carray, &n);
  for (i = 0; i < n; ++i) {
    conn = carray[i];
    /* If we've been holding the connection open, but we haven't written
     * for 15 seconds...
     */
    if (conn->hold_open_until_flushed) {
      tor_assert(conn->marked_for_close);
      if (now - conn->timestamp_lastwritten >= 15) {
        int severity;
        if (conn->type == CONN_TYPE_EXIT ||
            (conn->type == CONN_TYPE_DIR && conn->purpose == DIR_PURPOSE_SERVER))
          severity = LOG_INFO;
        else
          severity = LOG_NOTICE;
        log_fn(severity, LD_NET,
               "Giving up on marked_for_close conn that's been flushing for 15s (fd %d, type %s, state %s).",
               conn->s, conn_type_to_string(conn->type),
               conn_state_to_string(conn->type, conn->state));
        conn->hold_open_until_flushed = 0;
      }
    }
  }
}

/** Bind a new non-blocking socket listening to
 * <b>listenaddress</b>:<b>listenport</b>, and add this new connection
 * (of type <b>type</b>) to the connection array.
 *
 * If <b>listenaddress</b> includes a port, we bind on that port;
 * otherwise, we use listenport.
 */
static connection_t *
connection_create_listener(const char *listenaddress, uint16_t listenport,
                           int type)
{
  struct sockaddr_in listenaddr; /* where to bind */
  char *address = NULL;
  connection_t *conn;
  uint16_t usePort;
  uint32_t addr;
  int s; /* the socket we're going to make */
#ifndef MS_WINDOWS
  int one=1;
#endif

  memset(&listenaddr,0,sizeof(struct sockaddr_in));
  if (parse_addr_port(listenaddress, &address, &addr, &usePort)<0) {
    warn(LD_CONFIG, "Error parsing/resolving ListenAddress %s",listenaddress);
    return NULL;
  }

  if (usePort==0)
    usePort = listenport;
  listenaddr.sin_addr.s_addr = htonl(addr);
  listenaddr.sin_family = AF_INET;
  listenaddr.sin_port = htons((uint16_t) usePort);

  notice(LD_NET, "Opening %s on %s:%d",
         conn_type_to_string(type), address, usePort);

  s = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
  if (s < 0) {
    warn(LD_NET,"Socket creation failed.");
    goto err;
  } else if (!SOCKET_IS_POLLABLE(s)) {
    warn(LD_NET,"Too many connections; can't create pollable listener.");
    tor_close_socket(s);
    goto err;
  }

#ifndef MS_WINDOWS
  /* REUSEADDR on normal places means you can rebind to the port
   * right after somebody else has let it go. But REUSEADDR on win32
   * means you can bind to the port _even when somebody else
   * already has it bound_. So, don't do that on Win32. */
  setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (void*) &one, sizeof(one));
#endif

  if (bind(s,(struct sockaddr *)&listenaddr,sizeof(listenaddr)) < 0) {
    warn(LD_NET, "Could not bind to %s:%u: %s", address, usePort,
         tor_socket_strerror(tor_socket_errno(s)));
    goto err;
  }

  if (listen(s,SOMAXCONN) < 0) {
    warn(LD_NET, "Could not listen on %s:%u: %s", address, usePort,
         tor_socket_strerror(tor_socket_errno(s)));
    goto err;
  }

  set_socket_nonblocking(s);

  conn = connection_new(type);
  conn->s = s;
  conn->address = address;
  address = NULL;
  conn->port = usePort;

  if (connection_add(conn) < 0) { /* no space, forget it */
    warn(LD_NET,"connection_add failed. Giving up.");
    connection_free(conn);
    goto err;
  }

  debug(LD_NET,"%s listening on port %u.",conn_type_to_string(type), usePort);

  conn->state = LISTENER_STATE_READY;
  connection_start_reading(conn);

  return conn;

 err:
  tor_free(address);
  return NULL;
}

/** Do basic sanity checking on a newly received socket. Return 0
 * if it looks ok, else return -1. */
static int
check_sockaddr_in(struct sockaddr *sa, int len, int level)
{
  int ok = 1;
  struct sockaddr_in *sin=(struct sockaddr_in*)sa;

  if (len != sizeof(struct sockaddr_in)) {
    log_fn(level, LD_NET, "Length of address not as expected: %d vs %d",
           len,(int)sizeof(struct sockaddr_in));
    ok = 0;
  }
  if (sa->sa_family != AF_INET) {
    log_fn(level, LD_NET, "Family of address not as expected: %d vs %d",
           sa->sa_family, AF_INET);
    ok = 0;
  }
  if (sin->sin_addr.s_addr == 0 || sin->sin_port == 0) {
    log_fn(level, LD_NET, "Address for new connection has address/port equal to zero.");
    ok = 0;
  }
  return ok ? 0 : -1;
}

/** The listener connection <b>conn</b> told poll() it wanted to read.
 * Call accept() on conn-\>s, and add the new connection if necessary.
 */
static int
connection_handle_listener_read(connection_t *conn, int new_type)
{
  int news; /* the new socket */
  connection_t *newconn;
  /* information about the remote peer when connecting to other routers */
  struct sockaddr_in remote;
  char addrbuf[256];
  /* length of the remote address. Must be whatever accept() needs. */
  socklen_t remotelen = 256;
  char tmpbuf[INET_NTOA_BUF_LEN];
  tor_assert((size_t)remotelen >= sizeof(struct sockaddr_in));
  memset(addrbuf, 0, sizeof(addrbuf));

  news = accept(conn->s,(struct sockaddr *)&addrbuf,&remotelen);
  if (!SOCKET_IS_POLLABLE(news)) {
    /* accept() error, or too many conns to poll */
    int e;
    if (news>=0) {
      /* Too many conns to poll. */
      warn(LD_NET,"Too many connections; couldn't accept connection.");
      tor_close_socket(news);
      return 0;
    }
    e = tor_socket_errno(conn->s);
    if (ERRNO_IS_ACCEPT_EAGAIN(e)) {
      return 0; /* he hung up before we could accept(). that's fine. */
    } else if (ERRNO_IS_ACCEPT_RESOURCE_LIMIT(e)) {
      notice(LD_NET,"accept failed: %s. Dropping incoming connection.",
             tor_socket_strerror(e));
      return 0;
    }
    /* else there was a real error. */
    warn(LD_NET,"accept() failed: %s. Closing listener.",
         tor_socket_strerror(e));
    connection_mark_for_close(conn);
    return -1;
  }
  debug(LD_NET,"Connection accepted on socket %d (child of fd %d).",news,conn->s);

  set_socket_nonblocking(news);

  if (check_sockaddr_in((struct sockaddr*)addrbuf, remotelen, LOG_INFO)<0) {
    info(LD_NET, "accept() returned a strange address; trying getsockname().");
    remotelen=256;
    memset(addrbuf, 0, sizeof(addrbuf));
    if (getsockname(news, (struct sockaddr*)addrbuf, &remotelen)<0) {
      warn(LD_NET, "getsockname() failed.");
    } else {
      if (check_sockaddr_in((struct sockaddr*)addrbuf, remotelen, LOG_WARN)<0) {
        warn(LD_NET,"Something's wrong with this conn. Closing it.");
        tor_close_socket(news);
        return 0;
      }
    }
  }
  memcpy(&remote, addrbuf, sizeof(struct sockaddr_in));

  /* process entrance policies here, before we even create the connection */
  if (new_type == CONN_TYPE_AP) {
    /* check sockspolicy to see if we should accept it */
    if (socks_policy_permits_address(ntohl(remote.sin_addr.s_addr)) == 0) {
      tor_inet_ntoa(&remote.sin_addr, tmpbuf, sizeof(tmpbuf));
      notice(LD_APP,"Denying socks connection from untrusted address %s.",
             tmpbuf);
      tor_close_socket(news);
      return 0;
    }
  }
  if (new_type == CONN_TYPE_DIR) {
    /* check dirpolicy to see if we should accept it */
    if (dir_policy_permits_address(ntohl(remote.sin_addr.s_addr)) == 0) {
      tor_inet_ntoa(&remote.sin_addr, tmpbuf, sizeof(tmpbuf));
      notice(LD_DIRSERV,"Denying dir connection from address %s.",
             tmpbuf);
      tor_close_socket(news);
      return 0;
    }
  }

  newconn = connection_new(new_type);
  newconn->s = news;

  /* remember the remote address */
  newconn->addr = ntohl(remote.sin_addr.s_addr);
  newconn->port = ntohs(remote.sin_port);
  newconn->address = tor_dup_addr(newconn->addr);

  if (connection_add(newconn) < 0) { /* no space, forget it */
    connection_free(newconn);
    return 0; /* no need to tear down the parent */
  }

  if (connection_init_accepted_conn(newconn) < 0) {
    connection_mark_for_close(newconn);
    return 0;
  }
  return 0;
}

/** Initialize states for newly accepted connection <b>conn</b>.
 * If conn is an OR, start the tls handshake.
 */
static int
connection_init_accepted_conn(connection_t *conn)
{
  connection_start_reading(conn);

  switch (conn->type) {
    case CONN_TYPE_OR:
      return connection_tls_start_handshake(conn, 1);
    case CONN_TYPE_AP:
      conn->state = AP_CONN_STATE_SOCKS_WAIT;
      break;
    case CONN_TYPE_DIR:
      conn->purpose = DIR_PURPOSE_SERVER;
      conn->state = DIR_CONN_STATE_SERVER_COMMAND_WAIT;
      break;
    case CONN_TYPE_CONTROL:
      conn->state = CONTROL_CONN_STATE_NEEDAUTH_V0;
      break;
  }
  return 0;
}

/** Take conn, make a nonblocking socket; try to connect to
 * addr:port (they arrive in *host order*). If fail, return -1. Else
 * assign s to conn-\>s: if connected return 1, if EAGAIN return 0.
 *
 * address is used to make the logs useful.
 *
 * On success, add conn to the list of polled connections.
 */
int
connection_connect(connection_t *conn, char *address,
                   uint32_t addr, uint16_t port)
{
  int s, inprogress = 0;
  struct sockaddr_in dest_addr;
  or_options_t *options = get_options();

  s = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
  if (s < 0) {
    warn(LD_NET,"Error creating network socket: %s",
         tor_socket_strerror(tor_socket_errno(-1)));
    return -1;
  } else if (!SOCKET_IS_POLLABLE(s)) {
    warn(LD_NET,
         "Too many connections; can't create pollable connection to %s",
         safe_str(address));
    tor_close_socket(s);
    return -1;
  }

  if (options->OutboundBindAddress) {
    struct sockaddr_in ext_addr;

    memset(&ext_addr, 0, sizeof(ext_addr));
    ext_addr.sin_family = AF_INET;
    ext_addr.sin_port = 0;
    if (!tor_inet_aton(options->OutboundBindAddress, &ext_addr.sin_addr)) {
      warn(LD_CONFIG,"Outbound bind address '%s' didn't parse. Ignoring.",
           options->OutboundBindAddress);
    } else {
      if (bind(s, (struct sockaddr*)&ext_addr, sizeof(ext_addr)) < 0) {
        warn(LD_NET,"Error binding network socket: %s",
             tor_socket_strerror(tor_socket_errno(s)));
        return -1;
      }
    }
  }

  set_socket_nonblocking(s);

  memset(&dest_addr,0,sizeof(dest_addr));
  dest_addr.sin_family = AF_INET;
  dest_addr.sin_port = htons(port);
  dest_addr.sin_addr.s_addr = htonl(addr);

  debug(LD_NET,"Connecting to %s:%u.",safe_str(address),port);

  if (connect(s,(struct sockaddr *)&dest_addr,sizeof(dest_addr)) < 0) {
    int e = tor_socket_errno(s);
    if (!ERRNO_IS_CONN_EINPROGRESS(e)) {
      /* yuck. kill it. */
      info(LD_NET,"connect() to %s:%u failed: %s",safe_str(address),port,
           tor_socket_strerror(e));
      tor_close_socket(s);
      return -1;
    } else {
      inprogress = 1;
    }
  }

  if (!server_mode(options))
    client_check_address_changed(s);

  /* it succeeded. we're connected. */
  log_fn(inprogress?LOG_DEBUG:LOG_INFO, LD_NET,
         "Connection to %s:%u %s (sock %d).",safe_str(address),port,
         inprogress?"in progress":"established",s);
  conn->s = s;
  if (connection_add(conn) < 0) /* no space, forget it */
    return -1;
  return inprogress ? 0 : 1;
}

/**
 * Launch any configured listener connections of type <b>type</b>.  (A
 * listener is configured if <b>port_option</b> is non-zero.  If any
 * ListenAddress configuration options are given in <b>cfg</b>, create a
 * connection binding to each one.  Otherwise, create a single
 * connection binding to the address <b>default_addr</b>.)
 *
 * If <b>force</b> is true, close and re-open all listener connections.
 * Otherwise, only relaunch the listeners of this type if the number of
 * existing connections is not as configured (e.g., because one died),
 * or if the existing connections do not match those configured.
 *
 * Add all old conns that should be closed to <b>replaced_conns</b>.
 * Add all new connections to <b>new_conns</b>.
 */
static int
retry_listeners(int type, config_line_t *cfg,
                int port_option, const char *default_addr, int force,
                smartlist_t *replaced_conns,
                smartlist_t *new_conns)
{
  smartlist_t *launch = smartlist_create();
  int free_launch_elts = 1;
  config_line_t *c;
  int n_conn, i;
  connection_t *conn;
  connection_t **carray;
  config_line_t *line;

  if (cfg && port_option) {
    for (c = cfg; c; c = c->next) {
      smartlist_add(launch, c);
    }
    free_launch_elts = 0;
  } else if (port_option) {
    line = tor_malloc_zero(sizeof(config_line_t));
    line->key = tor_strdup("");
    line->value = tor_strdup(default_addr);
    smartlist_add(launch, line);
  }

  /*
  SMARTLIST_FOREACH(launch, config_line_t *, l,
                    log_fn(LOG_NOTICE, "#%s#%s", l->key, l->value));
  */

  get_connection_array(&carray,&n_conn);
  for (i=0; i < n_conn; ++i) {
    conn = carray[i];
    if (conn->type != type || conn->marked_for_close)
      continue;
    if (force) {
      /* It's a listener, and we're relaunching all listeners of this
       * type. Close this one. */
      log_fn(LOG_NOTICE, LD_NET, "Closing %s on %s:%d",
             conn_type_to_string(type), conn->address, conn->port);
      connection_close_immediate(conn);
      connection_mark_for_close(conn);
      continue;
    }
    /* Okay, so this is a listener.  Is it configured? */
    line = NULL;
    SMARTLIST_FOREACH(launch, config_line_t *, wanted,
      {
        char *address=NULL;
        uint16_t port;
        if (! parse_addr_port(wanted->value, &address, NULL, &port)) {
          int addr_matches = !strcasecmp(address, conn->address);
          tor_free(address);
          if (! port)
            port = port_option;
          if (port == conn->port && addr_matches) {
            line = wanted;
            break;
          }
        }
      });
    if (! line) {
      /* This one isn't configured. Close it. */
      notice(LD_NET, "Closing %s on %s:%d",
             conn_type_to_string(type), conn->address, conn->port);
      if (replaced_conns) {
        smartlist_add(replaced_conns, conn);
      } else {
        connection_close_immediate(conn);
        connection_mark_for_close(conn);
      }
    } else {
      /* It's configured; we don't need to launch it. */
//      debug(LD_NET, "Already have %s on %s:%d",
//             conn_type_to_string(type), conn->address, conn->port);
      smartlist_remove(launch, line);
      if (free_launch_elts)
        config_free_lines(line);
    }
  }

  /* Now open all the listeners that are configured but not opened. */
  i = 0;
  SMARTLIST_FOREACH(launch, config_line_t *, cfg,
    {
      conn = connection_create_listener(cfg->value, (uint16_t) port_option,
                                        type);
      if (!conn) {
        i = -1;
      } else {
        if (new_conns)
          smartlist_add(new_conns, conn);
      }
  });

  if (free_launch_elts) {
    SMARTLIST_FOREACH(launch, config_line_t *, cfg,
                      config_free_lines(cfg));
  }
  smartlist_free(launch);

  return i;
}

/** (Re)launch listeners for each port you should have open.  If
 * <b>force</b> is true, close and relaunch all listeners. If <b>force</b>
 * is false, then only relaunch listeners when we have the wrong number of
 * connections for a given type.
 *
 * Add all old conns that should be closed to <b>replaced_conns</b>.
 * Add all new connections to <b>new_conns</b>.
 */
int
retry_all_listeners(int force, smartlist_t *replaced_conns,
                    smartlist_t *new_conns)
{
  or_options_t *options = get_options();

  if (server_mode(options) &&
      retry_listeners(CONN_TYPE_OR_LISTENER, options->ORListenAddress,
                      options->ORPort, "0.0.0.0", force,
                      replaced_conns, new_conns)<0)
    return -1;
  if (retry_listeners(CONN_TYPE_DIR_LISTENER, options->DirListenAddress,
                      options->DirPort, "0.0.0.0", force,
                      replaced_conns, new_conns)<0)
    return -1;
  if (retry_listeners(CONN_TYPE_AP_LISTENER, options->SocksListenAddress,
                      options->SocksPort, "127.0.0.1", force,
                      replaced_conns, new_conns)<0)
    return -1;
  if (retry_listeners(CONN_TYPE_CONTROL_LISTENER, NULL,
                      options->ControlPort, "127.0.0.1", force,
                      replaced_conns, new_conns)<0)
    return -1;

  return 0;
}

extern int global_read_bucket, global_write_bucket;

/** How many bytes at most can we read onto this connection? */
static int
connection_bucket_read_limit(connection_t *conn)
{
  int at_most;

  /* do a rudimentary round-robin so one circuit can't hog a connection */
  if (connection_speaks_cells(conn)) {
    at_most = 32*(CELL_NETWORK_SIZE);
  } else {
    at_most = 32*(RELAY_PAYLOAD_SIZE);
  }

  if (at_most > global_read_bucket)
    at_most = global_read_bucket;

  if (connection_speaks_cells(conn) && conn->state == OR_CONN_STATE_OPEN)
    if (at_most > conn->receiver_bucket)
      at_most = conn->receiver_bucket;

  if (at_most < 0)
    return 0;
  return at_most;
}

/** How many bytes at most can we write onto this connection? */
int
connection_bucket_write_limit(connection_t *conn)
{
  unsigned int at_most;

  /* do a rudimentary round-robin so one circuit can't hog a connection */
  if (connection_speaks_cells(conn)) {
    at_most = 32*(CELL_NETWORK_SIZE);
  } else {
    at_most = 32*(RELAY_PAYLOAD_SIZE);
  }

  if (at_most > conn->outbuf_flushlen)
    at_most = conn->outbuf_flushlen;

#if 0 /* don't enable til we actually do write limiting */
  if (at_most > global_write_bucket)
    at_most = global_write_bucket;
#endif
  return at_most;
}

/** We just read num_read onto conn. Decrement buckets appropriately. */
static void
connection_read_bucket_decrement(connection_t *conn, int num_read)
{
  global_read_bucket -= num_read; //tor_assert(global_read_bucket >= 0);
  if (connection_speaks_cells(conn) && conn->state == OR_CONN_STATE_OPEN) {
    conn->receiver_bucket -= num_read; //tor_assert(conn->receiver_bucket >= 0);
  }
}

/** DOCDOC */
static void
connection_consider_empty_buckets(connection_t *conn)
{
  if (global_read_bucket <= 0) {
    LOG_FN_CONN(conn, (LOG_DEBUG,LD_NET,"global bucket exhausted. Pausing."));
    conn->wants_to_read = 1;
    connection_stop_reading(conn);
    return;
  }
  if (connection_speaks_cells(conn) &&
      conn->state == OR_CONN_STATE_OPEN &&
      conn->receiver_bucket <= 0) {
    LOG_FN_CONN(conn, (LOG_DEBUG,LD_NET,"receiver bucket exhausted. Pausing."));
    conn->wants_to_read = 1;
    connection_stop_reading(conn);
  }
}

/** Initialize the global read bucket to options->BandwidthBurst,
 * and current_time to the current time. */
void
connection_bucket_init(void)
{
  or_options_t *options = get_options();
  global_read_bucket = (int)options->BandwidthBurst; /* start it at max traffic */
  global_write_bucket = (int)options->BandwidthBurst; /* start it at max traffic */
}

/** A second has rolled over; increment buckets appropriately. */
void
connection_bucket_refill(struct timeval *now)
{
  int i, n;
  connection_t *conn;
  connection_t **carray;
  or_options_t *options = get_options();

  /* refill the global buckets */
  if (global_read_bucket < (int)options->BandwidthBurst) {
    global_read_bucket += (int)options->BandwidthRate;
    debug(LD_NET,"global_read_bucket now %d.", global_read_bucket);
  }
  if (global_write_bucket < (int)options->BandwidthBurst) {
    global_write_bucket += (int)options->BandwidthRate;
    debug(LD_NET,"global_write_bucket now %d.", global_write_bucket);
  }

  /* refill the per-connection buckets */
  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];

    if (connection_receiver_bucket_should_increase(conn)) {
      conn->receiver_bucket = conn->bandwidth;
      //log_fn(LOG_DEBUG,"Receiver bucket %d now %d.", i, conn->receiver_bucket);
    }

    if (conn->wants_to_read == 1 /* it's marked to turn reading back on now */
        && global_read_bucket > 0 /* and we're allowed to read */
        && global_write_bucket > 0 /* and we're allowed to write (XXXX,
                                    * not the best place to check this.) */
        && (!connection_speaks_cells(conn) ||
            conn->state != OR_CONN_STATE_OPEN ||
            conn->receiver_bucket > 0)) {
      /* and either a non-cell conn or a cell conn with non-empty bucket */
      LOG_FN_CONN(conn, (LOG_DEBUG,LD_NET,"waking up conn (fd %d)",conn->s));
      conn->wants_to_read = 0;
      connection_start_reading(conn);
      if (conn->wants_to_write == 1) {
        conn->wants_to_write = 0;
        connection_start_writing(conn);
      }
    }
  }
}

/** Is the receiver bucket for connection <b>conn</b> low enough that we
 * should add another pile of tokens to it?
 */
static int
connection_receiver_bucket_should_increase(connection_t *conn)
{
  tor_assert(conn);

  if (!connection_speaks_cells(conn))
    return 0; /* edge connections don't use receiver_buckets */
  if (conn->state != OR_CONN_STATE_OPEN)
    return 0; /* only open connections play the rate limiting game */

  if (conn->receiver_bucket >= conn->bandwidth)
    return 0;

  return 1;
}

/** Read bytes from conn-\>s and process them.
 *
 * This function gets called from conn_read() in main.c, either
 * when poll() has declared that conn wants to read, or (for OR conns)
 * when there are pending TLS bytes.
 *
 * It calls connection_read_to_buf() to bring in any new bytes,
 * and then calls connection_process_inbuf() to process them.
 *
 * Mark the connection and return -1 if you want to close it, else
 * return 0.
 */
int
connection_handle_read(connection_t *conn)
{
  int max_to_read=-1, try_to_read;

  if (conn->marked_for_close)
    return 0; /* do nothing */

  conn->timestamp_lastread = time(NULL);

  switch (conn->type) {
    case CONN_TYPE_OR_LISTENER:
      return connection_handle_listener_read(conn, CONN_TYPE_OR);
    case CONN_TYPE_AP_LISTENER:
      return connection_handle_listener_read(conn, CONN_TYPE_AP);
    case CONN_TYPE_DIR_LISTENER:
      return connection_handle_listener_read(conn, CONN_TYPE_DIR);
    case CONN_TYPE_CONTROL_LISTENER:
      return connection_handle_listener_read(conn, CONN_TYPE_CONTROL);
  }

loop_again:
  try_to_read = max_to_read;
  tor_assert(!conn->marked_for_close);
  if (connection_read_to_buf(conn, &max_to_read) < 0) {
    /* There's a read error; kill the connection.*/
    connection_close_immediate(conn); /* Don't flush; connection is dead. */
    if (CONN_IS_EDGE(conn)) {
      connection_edge_end_errno(conn, conn->cpath_layer);
      if (conn->socks_request) /* broken, so don't send a socks reply back */
        conn->socks_request->has_finished = 1;
    }
    connection_mark_for_close(conn);
    return -1;
  }
  if (CONN_IS_EDGE(conn) &&
      try_to_read != max_to_read) {
    /* instruct it not to try to package partial cells. */
    if (connection_process_inbuf(conn, 0) < 0) {
      return -1;
    }
    if (!conn->marked_for_close &&
        connection_is_reading(conn) &&
        !conn->inbuf_reached_eof &&
        max_to_read > 0)
      goto loop_again; /* try reading again, in case more is here now */
  }
  /* one last try, packaging partial cells and all. */
  if (!conn->marked_for_close &&
      connection_process_inbuf(conn, 1) < 0) {
    return -1;
  }
  if (!conn->marked_for_close &&
      conn->inbuf_reached_eof &&
      connection_reached_eof(conn) < 0) {
    return -1;
  }
  return 0;
}

/** Pull in new bytes from conn-\>s onto conn-\>inbuf, either
 * directly or via TLS. Reduce the token buckets by the number of
 * bytes read.
 *
 * If *max_to_read is -1, then decide it ourselves, else go with the
 * value passed to us. When returning, if it's changed, subtract the
 * number of bytes we read from *max_to_read.
 *
 * Return -1 if we want to break conn, else return 0.
 */
static int
connection_read_to_buf(connection_t *conn, int *max_to_read)
{
  int result, at_most = *max_to_read;
  size_t bytes_in_buf, more_to_read;

  if (at_most == -1) { /* we need to initialize it */
    /* how many bytes are we allowed to read? */
    at_most = connection_bucket_read_limit(conn);
  }

  bytes_in_buf = buf_capacity(conn->inbuf) - buf_datalen(conn->inbuf);
 again:
  if ((size_t)at_most > bytes_in_buf && bytes_in_buf >= 1024) {
    more_to_read = at_most - bytes_in_buf;
    at_most = bytes_in_buf;
  } else {
    more_to_read = 0;
  }

  if (connection_speaks_cells(conn) && conn->state > OR_CONN_STATE_PROXY_READING) {
    int pending;
    if (conn->state == OR_CONN_STATE_HANDSHAKING) {
      /* continue handshaking even if global token bucket is empty */
      return connection_tls_continue_handshake(conn);
    }

    debug(LD_NET,"%d: starting, inbuf_datalen %d (%d pending in tls object). at_most %d.",
          conn->s,(int)buf_datalen(conn->inbuf),tor_tls_get_pending_bytes(conn->tls), at_most);

    /* else open, or closing */
    result = read_to_buf_tls(conn->tls, at_most, conn->inbuf);

    switch (result) {
      case TOR_TLS_CLOSE:
        info(LD_NET,"TLS connection closed on read. Closing. (Nickname %s, address %s",
             conn->nickname ? conn->nickname : "not set", conn->address);
        return -1;
      case TOR_TLS_ERROR:
        info(LD_NET,"tls error. breaking (nickname %s, address %s).",
             conn->nickname ? conn->nickname : "not set", conn->address);
        return -1;
      case TOR_TLS_WANTWRITE:
        connection_start_writing(conn);
        return 0;
      case TOR_TLS_WANTREAD: /* we're already reading */
      case TOR_TLS_DONE: /* no data read, so nothing to process */
        result = 0;
        break; /* so we call bucket_decrement below */
      default:
        break;
    }
    pending = tor_tls_get_pending_bytes(conn->tls);
    if (pending) {
      /* XXXX If we have any pending bytes, read them now.  This *can*
       * take us over our read allotment, but really we shouldn't be
       * believing that SSL bytes are the same as TCP bytes anyway. */
      int r2 = read_to_buf_tls(conn->tls, pending, conn->inbuf);
      if (r2<0) {
        warn(LD_BUG, "Bug: apparently, reading pending bytes can fail.");
        return -1;
      } else {
        result += r2;
      }
    }

  } else {
    CONN_LOG_PROTECT(conn,
        result = read_to_buf(conn->s, at_most, conn->inbuf,
                             &conn->inbuf_reached_eof));

//  log_fn(LOG_DEBUG,"read_to_buf returned %d.",read_result);

    if (result < 0)
      return -1;
  }

  if (result > 0) { /* change *max_to_read */
    *max_to_read = at_most - result;
  }

  if (result > 0 && !is_local_IP(conn->addr)) { /* remember it */
    rep_hist_note_bytes_read(result, time(NULL));
    connection_read_bucket_decrement(conn, result);
  }

  if (more_to_read && result == at_most) {
    bytes_in_buf = buf_capacity(conn->inbuf) - buf_datalen(conn->inbuf);
    tor_assert(bytes_in_buf < 1024);
    at_most = more_to_read;
    goto again;
  }

  /* Call even if result is 0, since the global read bucket may
   * have reached 0 on a different conn, and this guy needs to
   * know to stop reading. */
  connection_consider_empty_buckets(conn);

  return 0;
}

/** A pass-through to fetch_from_buf. */
int
connection_fetch_from_buf(char *string, size_t len, connection_t *conn)
{
  return fetch_from_buf(string, len, conn->inbuf);
}

/** Return conn-\>outbuf_flushlen: how many bytes conn wants to flush
 * from its outbuf. */
int
connection_wants_to_flush(connection_t *conn)
{
  return conn->outbuf_flushlen;
}

/** Are there too many bytes on edge connection <b>conn</b>'s outbuf to
 * send back a relay-level sendme yet? Return 1 if so, 0 if not. Used by
 * connection_edge_consider_sending_sendme().
 */
int
connection_outbuf_too_full(connection_t *conn)
{
  return (conn->outbuf_flushlen > 10*CELL_PAYLOAD_SIZE);
}

/** Try to flush more bytes onto conn-\>s.
 *
 * This function gets called either from conn_write() in main.c
 * when poll() has declared that conn wants to write, or below
 * from connection_write_to_buf() when an entire TLS record is ready.
 *
 * Update conn-\>timestamp_lastwritten to now, and call flush_buf
 * or flush_buf_tls appropriately. If it succeeds and there no more
 * more bytes on conn->outbuf, then call connection_finished_flushing
 * on it too.
 *
 * Mark the connection and return -1 if you want to close it, else
 * return 0.
 */
int
connection_handle_write(connection_t *conn)
{
  int e;
  socklen_t len=sizeof(e);
  int result;
  int max_to_write;
  time_t now = time(NULL);

  tor_assert(!connection_is_listener(conn));

  if (conn->marked_for_close)
    return 0; /* do nothing */

  conn->timestamp_lastwritten = now;

  /* Sometimes, "writable" means "connected". */
  if (connection_state_is_connecting(conn)) {
    if (getsockopt(conn->s, SOL_SOCKET, SO_ERROR, (void*)&e, &len) < 0) {
      warn(LD_BUG,"getsockopt() syscall failed?! Please report to tor-ops.");
      if (CONN_IS_EDGE(conn))
        connection_edge_end_errno(conn, conn->cpath_layer);
      connection_mark_for_close(conn);
      return -1;
    }
    if (e) {
      /* some sort of error, but maybe just inprogress still */
      if (!ERRNO_IS_CONN_EINPROGRESS(e)) {
        info(LD_NET,"in-progress connect failed. Removing.");
        if (CONN_IS_EDGE(conn))
          connection_edge_end_errno(conn, conn->cpath_layer);

        connection_close_immediate(conn);
        connection_mark_for_close(conn);
        /* it's safe to pass OPs to router_mark_as_down(), since it just
         * ignores unrecognized routers
         */
        if (conn->type == CONN_TYPE_OR && !get_options()->HttpsProxy)
          router_mark_as_down(conn->identity_digest);
        return -1;
      } else {
        return 0; /* no change, see if next time is better */
      }
    }
    /* The connection is successful. */
    if (connection_finished_connecting(conn)<0)
      return -1;
  }

  max_to_write = connection_bucket_write_limit(conn);

  if (connection_speaks_cells(conn) && conn->state > OR_CONN_STATE_PROXY_READING) {
    if (conn->state == OR_CONN_STATE_HANDSHAKING) {
      connection_stop_writing(conn);
      if (connection_tls_continue_handshake(conn) < 0) {
        connection_close_immediate(conn); /* Don't flush; connection is dead. */
        connection_mark_for_close(conn);
        return -1;
      }
      return 0;
    }

    /* else open, or closing */
    result = flush_buf_tls(conn->tls, conn->outbuf,
                           max_to_write, &conn->outbuf_flushlen);
    switch (result) {
      case TOR_TLS_ERROR:
      case TOR_TLS_CLOSE:
        info(LD_NET,result==TOR_TLS_ERROR?
             "tls error. breaking.":"TLS connection closed on flush");
        connection_close_immediate(conn); /* Don't flush; connection is dead. */
        connection_mark_for_close(conn);
        return -1;
      case TOR_TLS_WANTWRITE:
        debug(LD_NET,"wanted write.");
        /* we're already writing */
        return 0;
      case TOR_TLS_WANTREAD:
        /* Make sure to avoid a loop if the receive buckets are empty. */
        debug(LD_NET,"wanted read.");
        if (!connection_is_reading(conn)) {
          connection_stop_writing(conn);
          conn->wants_to_write = 1;
          /* we'll start reading again when the next second arrives,
           * and then also start writing again.
           */
        }
        /* else no problem, we're already reading */
        return 0;
      /* case TOR_TLS_DONE:
       * for TOR_TLS_DONE, fall through to check if the flushlen
       * is empty, so we can stop writing.
       */
    }
  } else {
    CONN_LOG_PROTECT(conn,
             result = flush_buf(conn->s, conn->outbuf,
                                max_to_write, &conn->outbuf_flushlen));
    if (result < 0) {
      if (CONN_IS_EDGE(conn))
        connection_edge_end_errno(conn, conn->cpath_layer);

      connection_close_immediate(conn); /* Don't flush; connection is dead. */
      connection_mark_for_close(conn);
      return -1;
    }
  }

  if (result > 0 && !is_local_IP(conn->addr)) { /* remember it */
    rep_hist_note_bytes_written(result, now);
    global_write_bucket -= result;
  }

  if (!connection_wants_to_flush(conn)) { /* it's done flushing */
    if (connection_finished_flushing(conn) < 0) {
      /* already marked */
      return -1;
    }
  }

  return 0;
}

/* A controller event has just happened with such urgency that we
 * need to write it onto controller <b>conn</b> immediately. */
void
_connection_controller_force_write(connection_t *conn)
{
  /* XXX This is hideous code duplication, but raising it seems a little
   * tricky for now.  Think more about this one.   We only call it for
   * EVENT_ERR_MSG, so messing with buckets a little isn't such a big problem.
   */
  int result;
  tor_assert(conn);
  tor_assert(!conn->tls);
  tor_assert(conn->type == CONN_TYPE_CONTROL);
  if (conn->marked_for_close || conn->s < 0)
    return;

  CONN_LOG_PROTECT(conn,
      result = flush_buf(conn->s, conn->outbuf,
                         conn->outbuf_flushlen, &conn->outbuf_flushlen));
  if (result < 0) {
    connection_close_immediate(conn); /* Don't flush; connection is dead. */
    connection_mark_for_close(conn);
    return;
  }

  if (result > 0 && !is_local_IP(conn->addr)) { /* remember it */
    rep_hist_note_bytes_written(result, time(NULL));
    global_write_bucket -= result;
  }

  if (!connection_wants_to_flush(conn)) { /* it's done flushing */
    if (connection_finished_flushing(conn) < 0) {
      /* already marked */
      return;
    }
  }
}

/** Append <b>len</b> bytes of <b>string</b> onto <b>conn</b>'s
 * outbuf, and ask it to start writing.
 */
void
connection_write_to_buf(const char *string, size_t len, connection_t *conn)
{
  int r;
  if (!len)
    return;
  /* if it's marked for close, only allow write if we mean to flush it */
  if (conn->marked_for_close && !conn->hold_open_until_flushed)
    return;

  CONN_LOG_PROTECT(conn, r = write_to_buf(string, len, conn->outbuf));
  if (r < 0) {
    if (CONN_IS_EDGE(conn)) {
      /* if it failed, it means we have our package/delivery windows set
         wrong compared to our max outbuf size. close the whole circuit. */
      warn(LD_NET,"write_to_buf failed. Closing circuit (fd %d).", conn->s);
      circuit_mark_for_close(circuit_get_by_edge_conn(conn));
    } else {
      warn(LD_NET,"write_to_buf failed. Closing connection (fd %d).", conn->s);
      connection_mark_for_close(conn);
    }
    return;
  }

  connection_start_writing(conn);
  conn->outbuf_flushlen += len;
}

/** Return the conn to addr/port that has the most recent
 * timestamp_created, or NULL if no such conn exists. */
connection_t *
connection_or_exact_get_by_addr_port(uint32_t addr, uint16_t port)
{
  int i, n;
  connection_t *conn, *best=NULL;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->type == CONN_TYPE_OR &&
        conn->addr == addr &&
        conn->port == port &&
        !conn->marked_for_close &&
        (!best || best->timestamp_created < conn->timestamp_created))
      best = conn;
  }
  return best;
}

/** Return a connection with given type, address, port, and purpose;
 * or NULL if no such connection exists. */
connection_t *
connection_get_by_type_addr_port_purpose(int type, uint32_t addr, uint16_t port,
                                         int purpose)
{
  int i, n;
  connection_t *conn;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->type == type &&
        conn->addr == addr &&
        conn->port == port &&
        conn->purpose == purpose &&
        !conn->marked_for_close)
      return conn;
  }
  return NULL;
}

/** Return the connection with id <b>id</b> if it is not already
 * marked for close.
 */
connection_t *
connection_get_by_global_id(uint32_t id)
{
  int i, n;
  connection_t *conn;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->global_identifier == id) {
      if (!conn->marked_for_close)
        return conn;
      else
        return NULL;
    }
  }
  return NULL;
}

/** Return a connection of type <b>type</b> that is not marked for
 * close.
 */
connection_t *
connection_get_by_type(int type)
{
  int i, n;
  connection_t *conn;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->type == type && !conn->marked_for_close)
      return conn;
  }
  return NULL;
}

/** Return a connection of type <b>type</b> that is in state <b>state</b>,
 * and that is not marked for close.
 */
connection_t *
connection_get_by_type_state(int type, int state)
{
  int i, n;
  connection_t *conn;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->type == type && conn->state == state && !conn->marked_for_close)
      return conn;
  }
  return NULL;
}

/** Return the connection of type <b>type</b> that is in state
 * <b>state</b>, that was written to least recently, and that is not
 * marked for close.
 */
connection_t *
connection_get_by_type_state_lastwritten(int type, int state)
{
  int i, n;
  connection_t *conn, *best=NULL;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->type == type && conn->state == state && !conn->marked_for_close)
      if (!best || conn->timestamp_lastwritten < best->timestamp_lastwritten)
        best = conn;
  }
  return best;
}

/** Return a connection of type <b>type</b> that has rendquery equal
 * to <b>rendquery</b>, and that is not marked for close. If state
 * is non-zero, conn must be of that state too.
 */
connection_t *
connection_get_by_type_state_rendquery(int type, int state, const char *rendquery)
{
  int i, n;
  connection_t *conn;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->type == type &&
        !conn->marked_for_close &&
        (!state || state == conn->state) &&
        !rend_cmp_service_ids(rendquery, conn->rend_query))
      return conn;
  }
  return NULL;
}

/** Return an open, non-marked connection of a given type and purpose, or NULL
 * if no such connection exists. */
connection_t *
connection_get_by_type_purpose(int type, int purpose)
{
  int i, n;
  connection_t *conn;
  connection_t **carray;

  get_connection_array(&carray,&n);
  for (i=0;i<n;i++) {
    conn = carray[i];
    if (conn->type == type &&
        !conn->marked_for_close &&
        (purpose == conn->purpose))
      return conn;
  }
  return NULL;
}

/** Return 1 if <b>conn</b> is a listener conn, else return 0. */
int
connection_is_listener(connection_t *conn)
{
  if (conn->type == CONN_TYPE_OR_LISTENER ||
      conn->type == CONN_TYPE_AP_LISTENER ||
      conn->type == CONN_TYPE_DIR_LISTENER ||
      conn->type == CONN_TYPE_CONTROL_LISTENER)
    return 1;
  return 0;
}

/** Return 1 if <b>conn</b> is in state "open" and is not marked
 * for close, else return 0.
 */
int
connection_state_is_open(connection_t *conn)
{
  tor_assert(conn);

  if (conn->marked_for_close)
    return 0;

  if ((conn->type == CONN_TYPE_OR && conn->state == OR_CONN_STATE_OPEN) ||
      (conn->type == CONN_TYPE_AP && conn->state == AP_CONN_STATE_OPEN) ||
      (conn->type == CONN_TYPE_EXIT && conn->state == EXIT_CONN_STATE_OPEN) ||
      (conn->type == CONN_TYPE_CONTROL &&
       (conn->state == CONTROL_CONN_STATE_OPEN_V0 ||
        conn->state == CONTROL_CONN_STATE_OPEN_V1)))
    return 1;

  return 0;
}

/** Return 1 if conn is in 'connecting' state, else return 0. */
int
connection_state_is_connecting(connection_t *conn)
{
  tor_assert(conn);

  if (conn->marked_for_close)
    return 0;
  switch (conn->type)
    {
    case CONN_TYPE_OR:
      return conn->state == OR_CONN_STATE_CONNECTING;
    case CONN_TYPE_EXIT:
      return conn->state == EXIT_CONN_STATE_CONNECTING;
    case CONN_TYPE_DIR:
      return conn->state == DIR_CONN_STATE_CONNECTING;
    }

  return 0;
}

/** Write a destroy cell with circ ID <b>circ_id</b> onto OR connection
 * <b>conn</b>.
 *
 * Return 0.
 */
/*XXXX Why isn't this in connection_or.c?*/
int
connection_send_destroy(uint16_t circ_id, connection_t *conn)
{
  cell_t cell;

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

  memset(&cell, 0, sizeof(cell_t));
  cell.circ_id = circ_id;
  cell.command = CELL_DESTROY;
  debug(LD_OR,"Sending destroy (circID %d).", circ_id);
  connection_or_write_cell_to_buf(&cell, conn);
  return 0;
}

/** Alloocates a base64'ed authenticator for use in http or https
 * auth, based on the input string <b>authenticator</b>. Returns it
 * if success, else returns NULL. */
char *
alloc_http_authenticator(const char *authenticator)
{
  /* an authenticator in Basic authentication
   * is just the string "username:password" */
  const int authenticator_length = strlen(authenticator);
  /* The base64_encode function needs a minimum buffer length
   * of 66 bytes. */
  const int base64_authenticator_length = (authenticator_length/48+1)*66;
  char *base64_authenticator = tor_malloc(base64_authenticator_length);
  if (base64_encode(base64_authenticator, base64_authenticator_length,
                    authenticator, authenticator_length) < 0) {
    tor_free(base64_authenticator); /* free and set to null */
  } else {
    /* remove extra \n at end of encoding */
    base64_authenticator[strlen(base64_authenticator) - 1] = 0;
  }
  return base64_authenticator;
}

/** DOCDOC
 * XXXX ipv6 NM
 */
static void
client_check_address_changed(int sock)
{
  uint32_t iface_ip, ip_out;
  struct sockaddr_in out_addr;
  socklen_t out_addr_len = sizeof(out_addr);
  uint32_t *ip;

  if (!last_interface_ip)
    get_interface_address(&last_interface_ip);
  if (!outgoing_addrs)
    outgoing_addrs = smartlist_create();

  if (getsockname(sock, (struct sockaddr*)&out_addr, &out_addr_len)<0) {
    int e = tor_socket_errno(sock);
    warn(LD_NET, "getsockname() failed: %s", tor_socket_strerror(e));
    return;
  }

  /* Okay.  If we've used this address previously, we're okay. */
  ip_out = ntohl(out_addr.sin_addr.s_addr);
  SMARTLIST_FOREACH(outgoing_addrs, uint32_t*, ip,
                    if (*ip == ip_out) return;
                    );

  /* Uh-oh.  We haven't connected from this address before. Has the interface
   * address changed? */
  if (get_interface_address(&iface_ip)<0)
    return;
  ip = tor_malloc(sizeof(uint32_t));
  *ip = ip_out;

  if (iface_ip == last_interface_ip) {
    /* Nope, it hasn't changed.  Add this address to the list. */
    smartlist_add(outgoing_addrs, ip);
  } else {
    /* The interface changed.  We're a client, so we need to regenerate our
     * keys.  First, reset the state. */
    log(LOG_NOTICE, LD_NET, "Our IP has changed.  Rotating keys...");
    last_interface_ip = iface_ip;
    SMARTLIST_FOREACH(outgoing_addrs, void*, ip, tor_free(ip));
    smartlist_clear(outgoing_addrs);
    smartlist_add(outgoing_addrs, ip);
    /* Okay, now change our keys. */
    init_keys(); /* XXXX NM return value-- safe to ignore? */
  }
}

/** Process new bytes that have arrived on conn-\>inbuf.
 *
 * This function just passes conn to the connection-specific
 * connection_*_process_inbuf() function. It also passes in
 * package_partial if wanted.
 */
static int
connection_process_inbuf(connection_t *conn, int package_partial)
{
  tor_assert(conn);

  switch (conn->type) {
    case CONN_TYPE_OR:
      return connection_or_process_inbuf(conn);
    case CONN_TYPE_EXIT:
    case CONN_TYPE_AP:
      return connection_edge_process_inbuf(conn, package_partial);
    case CONN_TYPE_DIR:
      return connection_dir_process_inbuf(conn);
    case CONN_TYPE_DNSWORKER:
      return connection_dns_process_inbuf(conn);
    case CONN_TYPE_CPUWORKER:
      return connection_cpu_process_inbuf(conn);
    case CONN_TYPE_CONTROL:
      return connection_control_process_inbuf(conn);
    default:
      err(LD_BUG,"Bug: got unexpected conn type %d.", conn->type);
      tor_fragile_assert();
      return -1;
  }
}

/** We just finished flushing bytes from conn-\>outbuf, and there
 * are no more bytes remaining.
 *
 * This function just passes conn to the connection-specific
 * connection_*_finished_flushing() function.
 */
static int
connection_finished_flushing(connection_t *conn)
{
  tor_assert(conn);

//  log_fn(LOG_DEBUG,"entered. Socket %u.", conn->s);

  switch (conn->type) {
    case CONN_TYPE_OR:
      return connection_or_finished_flushing(conn);
    case CONN_TYPE_AP:
    case CONN_TYPE_EXIT:
      return connection_edge_finished_flushing(conn);
    case CONN_TYPE_DIR:
      return connection_dir_finished_flushing(conn);
    case CONN_TYPE_DNSWORKER:
      return connection_dns_finished_flushing(conn);
    case CONN_TYPE_CPUWORKER:
      return connection_cpu_finished_flushing(conn);
    case CONN_TYPE_CONTROL:
      return connection_control_finished_flushing(conn);
    default:
      err(LD_BUG,"Bug: got unexpected conn type %d.", conn->type);
      tor_fragile_assert();
      return -1;
  }
}

/** Called when our attempt to connect() to another server has just
 * succeeded.
 *
 * This function just passes conn to the connection-specific
 * connection_*_finished_connecting() function.
 */
static int
connection_finished_connecting(connection_t *conn)
{
  tor_assert(conn);
  switch (conn->type)
    {
    case CONN_TYPE_OR:
      return connection_or_finished_connecting(conn);
    case CONN_TYPE_EXIT:
      return connection_edge_finished_connecting(conn);
    case CONN_TYPE_DIR:
      return connection_dir_finished_connecting(conn);
    default:
      err(LD_BUG,"Bug: got unexpected conn type %d.", conn->type);
      tor_fragile_assert();
      return -1;
  }
}

/** Callback: invoked when a connection reaches an EOF event. */
static int
connection_reached_eof(connection_t *conn)
{
  switch (conn->type) {
    case CONN_TYPE_OR:
      return connection_or_reached_eof(conn);
    case CONN_TYPE_AP:
    case CONN_TYPE_EXIT:
      return connection_edge_reached_eof(conn);
    case CONN_TYPE_DIR:
      return connection_dir_reached_eof(conn);
    case CONN_TYPE_DNSWORKER:
      return connection_dns_reached_eof(conn);
    case CONN_TYPE_CPUWORKER:
      return connection_cpu_reached_eof(conn);
    case CONN_TYPE_CONTROL:
      return connection_control_reached_eof(conn);
    default:
      err(LD_BUG,"Bug: got unexpected conn type %d.", conn->type);
      tor_fragile_assert();
      return -1;
  }
}

/** Verify that connection <b>conn</b> has all of its invariants
 * correct. Trigger an assert if anything is invalid.
 */
void
assert_connection_ok(connection_t *conn, time_t now)
{
  tor_assert(conn);
  tor_assert(conn->magic == CONNECTION_MAGIC);
  tor_assert(conn->type >= _CONN_TYPE_MIN);
  tor_assert(conn->type <= _CONN_TYPE_MAX);

  if (conn->outbuf_flushlen > 0) {
    tor_assert(connection_is_writing(conn) || conn->wants_to_write);
  }

  if (conn->hold_open_until_flushed)
    tor_assert(conn->marked_for_close);

  /* XXX check: wants_to_read, wants_to_write, s, poll_index,
   * marked_for_close. */

  /* buffers */
  if (!connection_is_listener(conn)) {
    assert_buf_ok(conn->inbuf);
    assert_buf_ok(conn->outbuf);
  }

  /* XXX Fix this; no longer so.*/
#if 0
  if (conn->type != CONN_TYPE_OR && conn->type != CONN_TYPE_DIR)
    tor_assert(!conn->pkey);
  /* pkey is set if we're a dir client, or if we're an OR in state OPEN
   * connected to another OR.
   */
#endif

  if (conn->type != CONN_TYPE_OR) {
    tor_assert(!conn->tls);
  } else {
    if (conn->state == OR_CONN_STATE_OPEN) {
      /* tor_assert(conn->bandwidth > 0); */
      /* the above isn't necessarily true: if we just did a TLS
       * handshake but we didn't recognize the other peer, or it
       * gave a bad cert/etc, then we won't have assigned bandwidth,
       * yet it will be open. -RD
       */
//      tor_assert(conn->receiver_bucket >= 0);
    }
//    tor_assert(conn->addr && conn->port);
    tor_assert(conn->address);
    if (conn->state > OR_CONN_STATE_PROXY_READING)
      tor_assert(conn->tls);
  }

  if (! CONN_IS_EDGE(conn)) {
    tor_assert(!conn->stream_id);
    tor_assert(!conn->next_stream);
    tor_assert(!conn->cpath_layer);
    tor_assert(!conn->package_window);
    tor_assert(!conn->deliver_window);
#if 0
    tor_assert(!conn->done_sending);
    tor_assert(!conn->done_receiving);
#endif
  } else {
    /* XXX unchecked: package window, deliver window. */
  }
  if (conn->type == CONN_TYPE_AP) {
    tor_assert(conn->socks_request);
    if (conn->state == AP_CONN_STATE_OPEN) {
      tor_assert(conn->socks_request->has_finished);
      if (!conn->marked_for_close) {
        tor_assert(conn->cpath_layer);
        assert_cpath_layer_ok(conn->cpath_layer);
      }
    }
  } else {
    tor_assert(!conn->socks_request);
  }
  if (conn->type == CONN_TYPE_EXIT) {
    tor_assert(conn->purpose == EXIT_PURPOSE_CONNECT ||
               conn->purpose == EXIT_PURPOSE_RESOLVE);
  } else if (conn->type != CONN_TYPE_DIR) {
    tor_assert(!conn->purpose); /* only used for dir types currently */
  }
  if (conn->type != CONN_TYPE_DIR) {
    tor_assert(!conn->requested_resource);
  }

  switch (conn->type)
    {
    case CONN_TYPE_OR_LISTENER:
    case CONN_TYPE_AP_LISTENER:
    case CONN_TYPE_DIR_LISTENER:
    case CONN_TYPE_CONTROL_LISTENER:
      tor_assert(conn->state == LISTENER_STATE_READY);
      break;
    case CONN_TYPE_OR:
      tor_assert(conn->state >= _OR_CONN_STATE_MIN);
      tor_assert(conn->state <= _OR_CONN_STATE_MAX);
      break;
    case CONN_TYPE_EXIT:
      tor_assert(conn->state >= _EXIT_CONN_STATE_MIN);
      tor_assert(conn->state <= _EXIT_CONN_STATE_MAX);
      break;
    case CONN_TYPE_AP:
      tor_assert(conn->state >= _AP_CONN_STATE_MIN);
      tor_assert(conn->state <= _AP_CONN_STATE_MAX);
      tor_assert(conn->socks_request);
      break;
    case CONN_TYPE_DIR:
      tor_assert(conn->state >= _DIR_CONN_STATE_MIN);
      tor_assert(conn->state <= _DIR_CONN_STATE_MAX);
      tor_assert(conn->purpose >= _DIR_PURPOSE_MIN);
      tor_assert(conn->purpose <= _DIR_PURPOSE_MAX);
      break;
    case CONN_TYPE_DNSWORKER:
      tor_assert(conn->state == DNSWORKER_STATE_IDLE ||
                 conn->state == DNSWORKER_STATE_BUSY);
      break;
    case CONN_TYPE_CPUWORKER:
      tor_assert(conn->state >= _CPUWORKER_STATE_MIN);
      tor_assert(conn->state <= _CPUWORKER_STATE_MAX);
      break;
    case CONN_TYPE_CONTROL:
      tor_assert(conn->state >= _CONTROL_CONN_STATE_MIN);
      tor_assert(conn->state <= _CONTROL_CONN_STATE_MAX);
      break;
    default:
      tor_assert(0);
  }
}