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
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
|
/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2013, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file entrynodes.c
* \brief Code to manage our fixed first nodes for various functions.
*
* Entry nodes can be guards (for general use) or bridges (for censorship
* circumvention).
**/
#include "or.h"
#include "circpathbias.h"
#include "circuitbuild.h"
#include "circuitstats.h"
#include "config.h"
#include "confparse.h"
#include "connection.h"
#include "connection_or.h"
#include "control.h"
#include "directory.h"
#include "entrynodes.h"
#include "main.h"
#include "microdesc.h"
#include "networkstatus.h"
#include "nodelist.h"
#include "policies.h"
#include "router.h"
#include "routerlist.h"
#include "routerparse.h"
#include "routerset.h"
#include "transports.h"
#include "statefile.h"
/** Information about a configured bridge. Currently this just matches the
* ones in the torrc file, but one day we may be able to learn about new
* bridges on our own, and remember them in the state file. */
typedef struct {
/** Address of the bridge. */
tor_addr_t addr;
/** TLS port for the bridge. */
uint16_t port;
/** Boolean: We are re-parsing our bridge list, and we are going to remove
* this one if we don't find it in the list of configured bridges. */
unsigned marked_for_removal : 1;
/** Expected identity digest, or all zero bytes if we don't know what the
* digest should be. */
char identity[DIGEST_LEN];
/** Name of pluggable transport protocol taken from its config line. */
char *transport_name;
/** When should we next try to fetch a descriptor for this bridge? */
download_status_t fetch_status;
/** A smartlist of k=v values to be passed to the SOCKS proxy, if
transports are used for this bridge. */
smartlist_t *socks_args;
} bridge_info_t;
/** A list of our chosen entry guards. */
static smartlist_t *entry_guards = NULL;
/** A value of 1 means that the entry_guards list has changed
* and those changes need to be flushed to disk. */
static int entry_guards_dirty = 0;
static void bridge_free(bridge_info_t *bridge);
static const node_t *choose_random_entry_impl(cpath_build_state_t *state,
int for_directory,
dirinfo_type_t dirtype);
/** Return the list of entry guards, creating it if necessary. */
const smartlist_t *
get_entry_guards(void)
{
if (! entry_guards)
entry_guards = smartlist_new();
return entry_guards;
}
/** Check whether the entry guard <b>e</b> is usable, given the directory
* authorities' opinion about the router (stored in <b>ri</b>) and the user's
* configuration (in <b>options</b>). Set <b>e</b>->bad_since
* accordingly. Return true iff the entry guard's status changes.
*
* If it's not usable, set *<b>reason</b> to a static string explaining why.
*/
static int
entry_guard_set_status(entry_guard_t *e, const node_t *node,
time_t now, const or_options_t *options,
const char **reason)
{
char buf[HEX_DIGEST_LEN+1];
int changed = 0;
*reason = NULL;
/* Do we want to mark this guard as bad? */
if (!node)
*reason = "unlisted";
else if (!node->is_running)
*reason = "down";
else if (options->UseBridges && (!node->ri ||
node->ri->purpose != ROUTER_PURPOSE_BRIDGE))
*reason = "not a bridge";
else if (options->UseBridges && !node_is_a_configured_bridge(node))
*reason = "not a configured bridge";
else if (!options->UseBridges && !node->is_possible_guard &&
!routerset_contains_node(options->EntryNodes,node))
*reason = "not recommended as a guard";
else if (routerset_contains_node(options->ExcludeNodes, node))
*reason = "excluded";
else if (e->path_bias_disabled)
*reason = "path-biased";
if (*reason && ! e->bad_since) {
/* Router is newly bad. */
base16_encode(buf, sizeof(buf), e->identity, DIGEST_LEN);
log_info(LD_CIRC, "Entry guard %s (%s) is %s: marking as unusable.",
e->nickname, buf, *reason);
e->bad_since = now;
control_event_guard(e->nickname, e->identity, "BAD");
changed = 1;
} else if (!*reason && e->bad_since) {
/* There's nothing wrong with the router any more. */
base16_encode(buf, sizeof(buf), e->identity, DIGEST_LEN);
log_info(LD_CIRC, "Entry guard %s (%s) is no longer unusable: "
"marking as ok.", e->nickname, buf);
e->bad_since = 0;
control_event_guard(e->nickname, e->identity, "GOOD");
changed = 1;
}
if (node) {
int is_dir = node_is_dir(node) && node->rs &&
node->rs->version_supports_microdesc_cache;
if (options->UseBridges && node_is_a_configured_bridge(node))
is_dir = 1;
if (e->is_dir_cache != is_dir) {
e->is_dir_cache = is_dir;
changed = 1;
}
}
return changed;
}
/** Return true iff enough time has passed since we last tried to connect
* to the unreachable guard <b>e</b> that we're willing to try again. */
static int
entry_is_time_to_retry(entry_guard_t *e, time_t now)
{
long diff;
if (e->last_attempted < e->unreachable_since)
return 1;
diff = now - e->unreachable_since;
if (diff < 6*60*60)
return now > (e->last_attempted + 60*60);
else if (diff < 3*24*60*60)
return now > (e->last_attempted + 4*60*60);
else if (diff < 7*24*60*60)
return now > (e->last_attempted + 18*60*60);
else
return now > (e->last_attempted + 36*60*60);
}
/** Return the node corresponding to <b>e</b>, if <b>e</b> is
* working well enough that we are willing to use it as an entry
* right now. (Else return NULL.) In particular, it must be
* - Listed as either up or never yet contacted;
* - Present in the routerlist;
* - Listed as 'stable' or 'fast' by the current dirserver consensus,
* if demanded by <b>need_uptime</b> or <b>need_capacity</b>
* (unless it's a configured EntryNode);
* - Allowed by our current ReachableORAddresses config option; and
* - Currently thought to be reachable by us (unless <b>assume_reachable</b>
* is true).
*
* If the answer is no, set *<b>msg</b> to an explanation of why.
*
* If need_descriptor is true, only return the node if we currently have
* a descriptor (routerinfo or microdesc) for it.
*/
static INLINE const node_t *
entry_is_live(entry_guard_t *e, int need_uptime, int need_capacity,
int assume_reachable, int need_descriptor, const char **msg)
{
const node_t *node;
const or_options_t *options = get_options();
tor_assert(msg);
if (e->path_bias_disabled) {
*msg = "path-biased";
return NULL;
}
if (e->bad_since) {
*msg = "bad";
return NULL;
}
/* no good if it's unreachable, unless assume_unreachable or can_retry. */
if (!assume_reachable && !e->can_retry &&
e->unreachable_since && !entry_is_time_to_retry(e, time(NULL))) {
*msg = "unreachable";
return NULL;
}
node = node_get_by_id(e->identity);
if (!node) {
*msg = "no node info";
return NULL;
}
if (need_descriptor && !node_has_descriptor(node)) {
*msg = "no descriptor";
return NULL;
}
if (get_options()->UseBridges) {
if (node_get_purpose(node) != ROUTER_PURPOSE_BRIDGE) {
*msg = "not a bridge";
return NULL;
}
if (!node_is_a_configured_bridge(node)) {
*msg = "not a configured bridge";
return NULL;
}
} else { /* !get_options()->UseBridges */
if (node_get_purpose(node) != ROUTER_PURPOSE_GENERAL) {
*msg = "not general-purpose";
return NULL;
}
}
if (routerset_contains_node(options->EntryNodes, node)) {
/* they asked for it, they get it */
need_uptime = need_capacity = 0;
}
if (node_is_unreliable(node, need_uptime, need_capacity, 0)) {
*msg = "not fast/stable";
return NULL;
}
if (!fascist_firewall_allows_node(node)) {
*msg = "unreachable by config";
return NULL;
}
return node;
}
/** Return the number of entry guards that we think are usable. */
int
num_live_entry_guards(int for_directory)
{
int n = 0;
const char *msg;
if (! entry_guards)
return 0;
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) {
if (for_directory && !entry->is_dir_cache)
continue;
if (entry_is_live(entry, 0, 1, 0, !for_directory, &msg))
++n;
} SMARTLIST_FOREACH_END(entry);
return n;
}
/** If <b>digest</b> matches the identity of any node in the
* entry_guards list, return that node. Else return NULL. */
entry_guard_t *
entry_guard_get_by_id_digest(const char *digest)
{
SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry,
if (tor_memeq(digest, entry->identity, DIGEST_LEN))
return entry;
);
return NULL;
}
/** Dump a description of our list of entry guards to the log at level
* <b>severity</b>. */
static void
log_entry_guards(int severity)
{
smartlist_t *elements = smartlist_new();
char *s;
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e)
{
const char *msg = NULL;
if (entry_is_live(e, 0, 1, 0, 0, &msg))
smartlist_add_asprintf(elements, "%s [%s] (up %s)",
e->nickname,
hex_str(e->identity, DIGEST_LEN),
e->made_contact ? "made-contact" : "never-contacted");
else
smartlist_add_asprintf(elements, "%s [%s] (%s, %s)",
e->nickname,
hex_str(e->identity, DIGEST_LEN),
msg,
e->made_contact ? "made-contact" : "never-contacted");
}
SMARTLIST_FOREACH_END(e);
s = smartlist_join_strings(elements, ",", 0, NULL);
SMARTLIST_FOREACH(elements, char*, cp, tor_free(cp));
smartlist_free(elements);
log_fn(severity,LD_CIRC,"%s",s);
tor_free(s);
}
/** Called when one or more guards that we would previously have used for some
* purpose are no longer in use because a higher-priority guard has become
* usable again. */
static void
control_event_guard_deferred(void)
{
/* XXXX We don't actually have a good way to figure out _how many_ entries
* are live for some purpose. We need an entry_is_even_slightly_live()
* function for this to work right. NumEntryGuards isn't reliable: if we
* need guards with weird properties, we can have more than that number
* live.
**/
#if 0
int n = 0;
const char *msg;
const or_options_t *options = get_options();
if (!entry_guards)
return;
SMARTLIST_FOREACH(entry_guards, entry_guard_t *, entry,
{
if (entry_is_live(entry, 0, 1, 0, &msg)) {
if (n++ == options->NumEntryGuards) {
control_event_guard(entry->nickname, entry->identity, "DEFERRED");
return;
}
}
});
#endif
}
/** Largest amount that we'll backdate chosen_on_date */
#define CHOSEN_ON_DATE_SLOP (30*86400)
/** Add a new (preferably stable and fast) router to our
* entry_guards list. Return a pointer to the router if we succeed,
* or NULL if we can't find any more suitable entries.
*
* If <b>chosen</b> is defined, use that one, and if it's not
* already in our entry_guards list, put it at the *beginning*.
* Else, put the one we pick at the end of the list. */
static const node_t *
add_an_entry_guard(const node_t *chosen, int reset_status, int prepend,
int for_discovery, int for_directory)
{
const node_t *node;
entry_guard_t *entry;
if (chosen) {
node = chosen;
entry = entry_guard_get_by_id_digest(node->identity);
if (entry) {
if (reset_status) {
entry->bad_since = 0;
entry->can_retry = 1;
}
entry->is_dir_cache = node->rs &&
node->rs->version_supports_microdesc_cache;
if (get_options()->UseBridges && node_is_a_configured_bridge(node))
entry->is_dir_cache = 1;
return NULL;
}
} else if (!for_directory) {
node = choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL, NULL);
if (!node)
return NULL;
} else {
const routerstatus_t *rs;
rs = router_pick_directory_server(MICRODESC_DIRINFO|V3_DIRINFO,
PDS_PREFER_TUNNELED_DIR_CONNS_|PDS_FOR_GUARD);
if (!rs)
return NULL;
node = node_get_by_id(rs->identity_digest);
if (!node)
return NULL;
}
if (node->using_as_guard)
return NULL;
if (entry_guard_get_by_id_digest(node->identity) != NULL) {
log_info(LD_CIRC, "I was about to add a duplicate entry guard.");
/* This can happen if we choose a guard, then the node goes away, then
* comes back. */
((node_t*) node)->using_as_guard = 1;
return NULL;
}
entry = tor_malloc_zero(sizeof(entry_guard_t));
log_info(LD_CIRC, "Chose %s as new entry guard.",
node_describe(node));
strlcpy(entry->nickname, node_get_nickname(node), sizeof(entry->nickname));
memcpy(entry->identity, node->identity, DIGEST_LEN);
entry->is_dir_cache = node_is_dir(node) && node->rs &&
node->rs->version_supports_microdesc_cache;
if (get_options()->UseBridges && node_is_a_configured_bridge(node))
entry->is_dir_cache = 1;
/* Choose expiry time smudged over the past month. The goal here
* is to a) spread out when Tor clients rotate their guards, so they
* don't all select them on the same day, and b) avoid leaving a
* precise timestamp in the state file about when we first picked
* this guard. For details, see the Jan 2010 or-dev thread. */
entry->chosen_on_date = time(NULL) - crypto_rand_int(3600*24*30);
entry->chosen_by_version = tor_strdup(VERSION);
/* Are we picking this guard because all of our current guards are
* down so we need another one (for_discovery is 1), or because we
* decided we need more variety in our guard list (for_discovery is 0)?
*
* Currently we hack this behavior into place by setting "made_contact"
* for guards of the latter variety, so we'll be willing to use any of
* them right off the bat.
*/
if (!for_discovery)
entry->made_contact = 1;
((node_t*)node)->using_as_guard = 1;
if (prepend)
smartlist_insert(entry_guards, 0, entry);
else
smartlist_add(entry_guards, entry);
control_event_guard(entry->nickname, entry->identity, "NEW");
control_event_guard_deferred();
log_entry_guards(LOG_INFO);
return node;
}
/** Choose how many entry guards or directory guards we'll use. If
* <b>for_directory</b> is true, we return how many directory guards to
* use; else we return how many entry guards to use. */
static int
decide_num_guards(const or_options_t *options, int for_directory)
{
if (for_directory && options->NumDirectoryGuards != 0)
return options->NumDirectoryGuards;
return options->NumEntryGuards;
}
/** If the use of entry guards is configured, choose more entry guards
* until we have enough in the list. */
static void
pick_entry_guards(const or_options_t *options, int for_directory)
{
int changed = 0;
const int num_needed = decide_num_guards(options, for_directory);
tor_assert(entry_guards);
while (num_live_entry_guards(for_directory) < num_needed) {
if (!add_an_entry_guard(NULL, 0, 0, 0, for_directory))
break;
changed = 1;
}
if (changed)
entry_guards_changed();
}
/** How long (in seconds) do we allow an entry guard to be nonfunctional,
* unlisted, excluded, or otherwise nonusable before we give up on it? */
#define ENTRY_GUARD_REMOVE_AFTER (30*24*60*60)
/** Release all storage held by <b>e</b>. */
static void
entry_guard_free(entry_guard_t *e)
{
if (!e)
return;
tor_free(e->chosen_by_version);
tor_free(e);
}
/**
* Return the minimum lifetime of working entry guard, in seconds,
* as given in the consensus networkstatus. (Plus CHOSEN_ON_DATE_SLOP,
* so that we can do the chosen_on_date randomization while achieving the
* desired minimum lifetime.)
*/
static int32_t
guards_get_lifetime(void)
{
const or_options_t *options = get_options();
#define DFLT_GUARD_LIFETIME (86400 * 60) /* Two months. */
#define MIN_GUARD_LIFETIME (86400 * 30) /* One months. */
#define MAX_GUARD_LIFETIME (86400 * 1826) /* Five years. */
if (options->GuardLifetime >= 1) {
return CLAMP(MIN_GUARD_LIFETIME,
options->GuardLifetime,
MAX_GUARD_LIFETIME) + CHOSEN_ON_DATE_SLOP;
}
return networkstatus_get_param(NULL, "GuardLifetime",
DFLT_GUARD_LIFETIME,
MIN_GUARD_LIFETIME,
MAX_GUARD_LIFETIME) + CHOSEN_ON_DATE_SLOP;
}
/** Remove any entry guard which was selected by an unknown version of Tor,
* or which was selected by a version of Tor that's known to select
* entry guards badly, or which was selected more 2 months ago. */
/* XXXX The "obsolete guards" and "chosen long ago guards" things should
* probably be different functions. */
static int
remove_obsolete_entry_guards(time_t now)
{
int changed = 0, i;
int32_t guard_lifetime = guards_get_lifetime();
for (i = 0; i < smartlist_len(entry_guards); ++i) {
entry_guard_t *entry = smartlist_get(entry_guards, i);
const char *ver = entry->chosen_by_version;
const char *msg = NULL;
tor_version_t v;
int version_is_bad = 0, date_is_bad = 0;
if (!ver) {
msg = "does not say what version of Tor it was selected by";
version_is_bad = 1;
} else if (tor_version_parse(ver, &v)) {
msg = "does not seem to be from any recognized version of Tor";
version_is_bad = 1;
} else {
char *tor_ver = NULL;
tor_asprintf(&tor_ver, "Tor %s", ver);
if ((tor_version_as_new_as(tor_ver, "0.1.0.10-alpha") &&
!tor_version_as_new_as(tor_ver, "0.1.2.16-dev")) ||
(tor_version_as_new_as(tor_ver, "0.2.0.0-alpha") &&
!tor_version_as_new_as(tor_ver, "0.2.0.6-alpha")) ||
/* above are bug 440; below are bug 1217 */
(tor_version_as_new_as(tor_ver, "0.2.1.3-alpha") &&
!tor_version_as_new_as(tor_ver, "0.2.1.23")) ||
(tor_version_as_new_as(tor_ver, "0.2.2.0-alpha") &&
!tor_version_as_new_as(tor_ver, "0.2.2.7-alpha"))) {
msg = "was selected without regard for guard bandwidth";
version_is_bad = 1;
}
tor_free(tor_ver);
}
if (!version_is_bad && entry->chosen_on_date + guard_lifetime < now) {
/* It's been too long since the date listed in our state file. */
msg = "was selected several months ago";
date_is_bad = 1;
}
if (version_is_bad || date_is_bad) { /* we need to drop it */
char dbuf[HEX_DIGEST_LEN+1];
tor_assert(msg);
base16_encode(dbuf, sizeof(dbuf), entry->identity, DIGEST_LEN);
log_fn(version_is_bad ? LOG_NOTICE : LOG_INFO, LD_CIRC,
"Entry guard '%s' (%s) %s. (Version=%s.) Replacing it.",
entry->nickname, dbuf, msg, ver?escaped(ver):"none");
control_event_guard(entry->nickname, entry->identity, "DROPPED");
entry_guard_free(entry);
smartlist_del_keeporder(entry_guards, i--);
log_entry_guards(LOG_INFO);
changed = 1;
}
}
return changed ? 1 : 0;
}
/** Remove all entry guards that have been down or unlisted for so
* long that we don't think they'll come up again. Return 1 if we
* removed any, or 0 if we did nothing. */
static int
remove_dead_entry_guards(time_t now)
{
char dbuf[HEX_DIGEST_LEN+1];
char tbuf[ISO_TIME_LEN+1];
int i;
int changed = 0;
for (i = 0; i < smartlist_len(entry_guards); ) {
entry_guard_t *entry = smartlist_get(entry_guards, i);
if (entry->bad_since &&
! entry->path_bias_disabled &&
entry->bad_since + ENTRY_GUARD_REMOVE_AFTER < now) {
base16_encode(dbuf, sizeof(dbuf), entry->identity, DIGEST_LEN);
format_local_iso_time(tbuf, entry->bad_since);
log_info(LD_CIRC, "Entry guard '%s' (%s) has been down or unlisted "
"since %s local time; removing.",
entry->nickname, dbuf, tbuf);
control_event_guard(entry->nickname, entry->identity, "DROPPED");
entry_guard_free(entry);
smartlist_del_keeporder(entry_guards, i);
log_entry_guards(LOG_INFO);
changed = 1;
} else
++i;
}
return changed ? 1 : 0;
}
/** Remove all currently listed entry guards. So new ones will be chosen. */
void
remove_all_entry_guards(void)
{
char dbuf[HEX_DIGEST_LEN+1];
while (smartlist_len(entry_guards)) {
entry_guard_t *entry = smartlist_get(entry_guards, 0);
base16_encode(dbuf, sizeof(dbuf), entry->identity, DIGEST_LEN);
log_info(LD_CIRC, "Entry guard '%s' (%s) has been dropped.",
entry->nickname, dbuf);
control_event_guard(entry->nickname, entry->identity, "DROPPED");
entry_guard_free(entry);
smartlist_del(entry_guards, 0);
}
log_entry_guards(LOG_INFO);
entry_guards_changed();
}
/** A new directory or router-status has arrived; update the down/listed
* status of the entry guards.
*
* An entry is 'down' if the directory lists it as nonrunning.
* An entry is 'unlisted' if the directory doesn't include it.
*
* Don't call this on startup; only on a fresh download. Otherwise we'll
* think that things are unlisted.
*/
void
entry_guards_compute_status(const or_options_t *options, time_t now)
{
int changed = 0;
digestmap_t *reasons;
if (! entry_guards)
return;
if (options->EntryNodes) /* reshuffle the entry guard list if needed */
entry_nodes_should_be_added();
reasons = digestmap_new();
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry)
{
const node_t *r = node_get_by_id(entry->identity);
const char *reason = NULL;
if (entry_guard_set_status(entry, r, now, options, &reason))
changed = 1;
if (entry->bad_since)
tor_assert(reason);
if (reason)
digestmap_set(reasons, entry->identity, (char*)reason);
}
SMARTLIST_FOREACH_END(entry);
if (remove_dead_entry_guards(now))
changed = 1;
if (remove_obsolete_entry_guards(now))
changed = 1;
if (changed) {
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) {
const char *reason = digestmap_get(reasons, entry->identity);
const char *live_msg = "";
const node_t *r = entry_is_live(entry, 0, 1, 0, 0, &live_msg);
log_info(LD_CIRC, "Summary: Entry %s [%s] is %s, %s%s%s, and %s%s.",
entry->nickname,
hex_str(entry->identity, DIGEST_LEN),
entry->unreachable_since ? "unreachable" : "reachable",
entry->bad_since ? "unusable" : "usable",
reason ? ", ": "",
reason ? reason : "",
r ? "live" : "not live / ",
r ? "" : live_msg);
} SMARTLIST_FOREACH_END(entry);
log_info(LD_CIRC, " (%d/%d entry guards are usable/new)",
num_live_entry_guards(0), smartlist_len(entry_guards));
log_entry_guards(LOG_INFO);
entry_guards_changed();
}
digestmap_free(reasons, NULL);
}
/** Called when a connection to an OR with the identity digest <b>digest</b>
* is established (<b>succeeded</b>==1) or has failed (<b>succeeded</b>==0).
* If the OR is an entry, change that entry's up/down status.
* Return 0 normally, or -1 if we want to tear down the new connection.
*
* If <b>mark_relay_status</b>, also call router_set_status() on this
* relay.
*
* XXX024 change succeeded and mark_relay_status into 'int flags'.
*/
int
entry_guard_register_connect_status(const char *digest, int succeeded,
int mark_relay_status, time_t now)
{
int changed = 0;
int refuse_conn = 0;
int first_contact = 0;
entry_guard_t *entry = NULL;
int idx = -1;
char buf[HEX_DIGEST_LEN+1];
if (! entry_guards)
return 0;
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
tor_assert(e);
if (tor_memeq(e->identity, digest, DIGEST_LEN)) {
entry = e;
idx = e_sl_idx;
break;
}
} SMARTLIST_FOREACH_END(e);
if (!entry)
return 0;
base16_encode(buf, sizeof(buf), entry->identity, DIGEST_LEN);
if (succeeded) {
if (entry->unreachable_since) {
log_info(LD_CIRC, "Entry guard '%s' (%s) is now reachable again. Good.",
entry->nickname, buf);
entry->can_retry = 0;
entry->unreachable_since = 0;
entry->last_attempted = now;
control_event_guard(entry->nickname, entry->identity, "UP");
changed = 1;
}
if (!entry->made_contact) {
entry->made_contact = 1;
first_contact = changed = 1;
}
} else { /* ! succeeded */
if (!entry->made_contact) {
/* We've never connected to this one. */
log_info(LD_CIRC,
"Connection to never-contacted entry guard '%s' (%s) failed. "
"Removing from the list. %d/%d entry guards usable/new.",
entry->nickname, buf,
num_live_entry_guards(0)-1, smartlist_len(entry_guards)-1);
control_event_guard(entry->nickname, entry->identity, "DROPPED");
entry_guard_free(entry);
smartlist_del_keeporder(entry_guards, idx);
log_entry_guards(LOG_INFO);
changed = 1;
} else if (!entry->unreachable_since) {
log_info(LD_CIRC, "Unable to connect to entry guard '%s' (%s). "
"Marking as unreachable.", entry->nickname, buf);
entry->unreachable_since = entry->last_attempted = now;
control_event_guard(entry->nickname, entry->identity, "DOWN");
changed = 1;
entry->can_retry = 0; /* We gave it an early chance; no good. */
} else {
char tbuf[ISO_TIME_LEN+1];
format_iso_time(tbuf, entry->unreachable_since);
log_debug(LD_CIRC, "Failed to connect to unreachable entry guard "
"'%s' (%s). It has been unreachable since %s.",
entry->nickname, buf, tbuf);
entry->last_attempted = now;
entry->can_retry = 0; /* We gave it an early chance; no good. */
}
}
/* if the caller asked us to, also update the is_running flags for this
* relay */
if (mark_relay_status)
router_set_status(digest, succeeded);
if (first_contact) {
/* We've just added a new long-term entry guard. Perhaps the network just
* came back? We should give our earlier entries another try too,
* and close this connection so we don't use it before we've given
* the others a shot. */
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
if (e == entry)
break;
if (e->made_contact) {
const char *msg;
const node_t *r = entry_is_live(e, 0, 1, 1, 0, &msg);
if (r && e->unreachable_since) {
refuse_conn = 1;
e->can_retry = 1;
}
}
} SMARTLIST_FOREACH_END(e);
if (refuse_conn) {
log_info(LD_CIRC,
"Connected to new entry guard '%s' (%s). Marking earlier "
"entry guards up. %d/%d entry guards usable/new.",
entry->nickname, buf,
num_live_entry_guards(0), smartlist_len(entry_guards));
log_entry_guards(LOG_INFO);
changed = 1;
}
}
if (changed)
entry_guards_changed();
return refuse_conn ? -1 : 0;
}
/** When we try to choose an entry guard, should we parse and add
* config's EntryNodes first? */
static int should_add_entry_nodes = 0;
/** Called when the value of EntryNodes changes in our configuration. */
void
entry_nodes_should_be_added(void)
{
log_info(LD_CIRC, "EntryNodes config option set. Putting configured "
"relays at the front of the entry guard list.");
should_add_entry_nodes = 1;
}
/** Update the using_as_guard fields of all the nodes. We do this after we
* remove entry guards from the list: This is the only function that clears
* the using_as_guard field. */
static void
update_node_guard_status(void)
{
smartlist_t *nodes = nodelist_get_list();
SMARTLIST_FOREACH(nodes, node_t *, node, node->using_as_guard = 0);
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) {
node_t *node = node_get_mutable_by_id(entry->identity);
if (node)
node->using_as_guard = 1;
} SMARTLIST_FOREACH_END(entry);
}
/** Adjust the entry guards list so that it only contains entries from
* EntryNodes, adding new entries from EntryNodes to the list as needed. */
static void
entry_guards_set_from_config(const or_options_t *options)
{
smartlist_t *entry_nodes, *worse_entry_nodes, *entry_fps;
smartlist_t *old_entry_guards_on_list, *old_entry_guards_not_on_list;
tor_assert(entry_guards);
should_add_entry_nodes = 0;
if (!options->EntryNodes) {
/* It's possible that a controller set EntryNodes, thus making
* should_add_entry_nodes set, then cleared it again, all before the
* call to choose_random_entry() that triggered us. If so, just return.
*/
return;
}
{
char *string = routerset_to_string(options->EntryNodes);
log_info(LD_CIRC,"Adding configured EntryNodes '%s'.", string);
tor_free(string);
}
entry_nodes = smartlist_new();
worse_entry_nodes = smartlist_new();
entry_fps = smartlist_new();
old_entry_guards_on_list = smartlist_new();
old_entry_guards_not_on_list = smartlist_new();
/* Split entry guards into those on the list and those not. */
routerset_get_all_nodes(entry_nodes, options->EntryNodes,
options->ExcludeNodes, 0);
SMARTLIST_FOREACH(entry_nodes, const node_t *,node,
smartlist_add(entry_fps, (void*)node->identity));
SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e, {
if (smartlist_contains_digest(entry_fps, e->identity))
smartlist_add(old_entry_guards_on_list, e);
else
smartlist_add(old_entry_guards_not_on_list, e);
});
/* Remove all currently configured guard nodes, excluded nodes, unreachable
* nodes, or non-Guard nodes from entry_nodes. */
SMARTLIST_FOREACH_BEGIN(entry_nodes, const node_t *, node) {
if (entry_guard_get_by_id_digest(node->identity)) {
SMARTLIST_DEL_CURRENT(entry_nodes, node);
continue;
} else if (routerset_contains_node(options->ExcludeNodes, node)) {
SMARTLIST_DEL_CURRENT(entry_nodes, node);
continue;
} else if (!fascist_firewall_allows_node(node)) {
SMARTLIST_DEL_CURRENT(entry_nodes, node);
continue;
} else if (! node->is_possible_guard) {
smartlist_add(worse_entry_nodes, (node_t*)node);
SMARTLIST_DEL_CURRENT(entry_nodes, node);
}
} SMARTLIST_FOREACH_END(node);
/* Now build the new entry_guards list. */
smartlist_clear(entry_guards);
/* First, the previously configured guards that are in EntryNodes. */
smartlist_add_all(entry_guards, old_entry_guards_on_list);
/* Next, scramble the rest of EntryNodes, putting the guards first. */
smartlist_shuffle(entry_nodes);
smartlist_shuffle(worse_entry_nodes);
smartlist_add_all(entry_nodes, worse_entry_nodes);
/* Next, the rest of EntryNodes */
SMARTLIST_FOREACH_BEGIN(entry_nodes, const node_t *, node) {
add_an_entry_guard(node, 0, 0, 1, 0);
if (smartlist_len(entry_guards) > options->NumEntryGuards * 10)
break;
} SMARTLIST_FOREACH_END(node);
log_notice(LD_GENERAL, "%d entries in guards", smartlist_len(entry_guards));
/* Finally, free the remaining previously configured guards that are not in
* EntryNodes. */
SMARTLIST_FOREACH(old_entry_guards_not_on_list, entry_guard_t *, e,
entry_guard_free(e));
update_node_guard_status();
smartlist_free(entry_nodes);
smartlist_free(worse_entry_nodes);
smartlist_free(entry_fps);
smartlist_free(old_entry_guards_on_list);
smartlist_free(old_entry_guards_not_on_list);
entry_guards_changed();
}
/** Return 0 if we're fine adding arbitrary routers out of the
* directory to our entry guard list, or return 1 if we have a
* list already and we must stick to it.
*/
int
entry_list_is_constrained(const or_options_t *options)
{
if (options->EntryNodes)
return 1;
if (options->UseBridges)
return 1;
return 0;
}
/** Return true iff this node can answer directory questions about
* microdescriptors. */
static int
node_understands_microdescriptors(const node_t *node)
{
tor_assert(node);
if (node->rs && node->rs->version_supports_microdesc_cache)
return 1;
if (node->ri && tor_version_supports_microdescriptors(node->ri->platform))
return 1;
return 0;
}
/** Return true iff <b>node</b> is able to answer directory questions
* of type <b>dirinfo</b>. */
static int
node_can_handle_dirinfo(const node_t *node, dirinfo_type_t dirinfo)
{
/* Checking dirinfo for any type other than microdescriptors isn't required
yet, since we only choose directory guards that can support microdescs,
routerinfos, and networkstatuses, AND we don't use directory guards if
we're configured to do direct downloads of anything else. The only case
where we might have a guard that doesn't know about a type of directory
information is when we're retrieving directory information from a
bridge. */
if ((dirinfo & MICRODESC_DIRINFO) &&
!node_understands_microdescriptors(node))
return 0;
return 1;
}
/** Pick a live (up and listed) entry guard from entry_guards. If
* <b>state</b> is non-NULL, this is for a specific circuit --
* make sure not to pick this circuit's exit or any node in the
* exit's family. If <b>state</b> is NULL, we're looking for a random
* guard (likely a bridge). If <b>dirinfo</b> is not NO_DIRINFO, then
* only select from nodes that know how to answer directory questions
* of that type. */
const node_t *
choose_random_entry(cpath_build_state_t *state)
{
return choose_random_entry_impl(state, 0, 0);
}
/** Pick a live (up and listed) directory guard from entry_guards for
* downloading information of type <b>type</b>. */
const node_t *
choose_random_dirguard(dirinfo_type_t type)
{
return choose_random_entry_impl(NULL, 1, type);
}
/** Helper for choose_random{entry,dirguard}. */
static const node_t *
choose_random_entry_impl(cpath_build_state_t *state, int for_directory,
dirinfo_type_t dirinfo_type)
{
const or_options_t *options = get_options();
smartlist_t *live_entry_guards = smartlist_new();
smartlist_t *exit_family = smartlist_new();
const node_t *chosen_exit =
state?build_state_get_exit_node(state) : NULL;
const node_t *node = NULL;
int need_uptime = state ? state->need_uptime : 0;
int need_capacity = state ? state->need_capacity : 0;
int preferred_min, consider_exit_family = 0;
int need_descriptor = !for_directory;
const int num_needed = decide_num_guards(options, for_directory);
if (chosen_exit) {
nodelist_add_node_and_family(exit_family, chosen_exit);
consider_exit_family = 1;
}
if (!entry_guards)
entry_guards = smartlist_new();
if (should_add_entry_nodes)
entry_guards_set_from_config(options);
if (!entry_list_is_constrained(options) &&
smartlist_len(entry_guards) < num_needed)
pick_entry_guards(options, for_directory);
retry:
smartlist_clear(live_entry_guards);
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, entry) {
const char *msg;
node = entry_is_live(entry, need_uptime, need_capacity, 0,
need_descriptor, &msg);
if (!node)
continue; /* down, no point */
if (for_directory) {
if (!entry->is_dir_cache)
continue; /* We need a directory and didn't get one. */
}
if (node == chosen_exit)
continue; /* don't pick the same node for entry and exit */
if (consider_exit_family && smartlist_contains(exit_family, node))
continue; /* avoid relays that are family members of our exit */
if (dirinfo_type != NO_DIRINFO &&
!node_can_handle_dirinfo(node, dirinfo_type))
continue; /* this node won't be able to answer our dir questions */
#if 0 /* since EntryNodes is always strict now, this clause is moot */
if (options->EntryNodes &&
!routerset_contains_node(options->EntryNodes, node)) {
/* We've come to the end of our preferred entry nodes. */
if (smartlist_len(live_entry_guards))
goto choose_and_finish; /* only choose from the ones we like */
if (options->StrictNodes) {
/* in theory this case should never happen, since
* entry_guards_set_from_config() drops unwanted relays */
tor_fragile_assert();
} else {
log_info(LD_CIRC,
"No relays from EntryNodes available. Using others.");
}
}
#endif
smartlist_add(live_entry_guards, (void*)node);
if (!entry->made_contact) {
/* Always start with the first not-yet-contacted entry
* guard. Otherwise we might add several new ones, pick
* the second new one, and now we've expanded our entry
* guard list without needing to. */
goto choose_and_finish;
}
if (smartlist_len(live_entry_guards) >= num_needed)
goto choose_and_finish; /* we have enough */
} SMARTLIST_FOREACH_END(entry);
if (entry_list_is_constrained(options)) {
/* If we prefer the entry nodes we've got, and we have at least
* one choice, that's great. Use it. */
preferred_min = 1;
} else {
/* Try to have at least 2 choices available. This way we don't
* get stuck with a single live-but-crummy entry and just keep
* using him.
* (We might get 2 live-but-crummy entry guards, but so be it.) */
preferred_min = 2;
}
if (smartlist_len(live_entry_guards) < preferred_min) {
if (!entry_list_is_constrained(options)) {
/* still no? try adding a new entry then */
/* XXX if guard doesn't imply fast and stable, then we need
* to tell add_an_entry_guard below what we want, or it might
* be a long time til we get it. -RD */
node = add_an_entry_guard(NULL, 0, 0, 1, for_directory);
if (node) {
entry_guards_changed();
/* XXX we start over here in case the new node we added shares
* a family with our exit node. There's a chance that we'll just
* load up on entry guards here, if the network we're using is
* one big family. Perhaps we should teach add_an_entry_guard()
* to understand nodes-to-avoid-if-possible? -RD */
goto retry;
}
}
if (!node && need_uptime) {
need_uptime = 0; /* try without that requirement */
goto retry;
}
if (!node && need_capacity) {
/* still no? last attempt, try without requiring capacity */
need_capacity = 0;
goto retry;
}
#if 0
/* Removing this retry logic: if we only allow one exit, and it is in the
same family as all our entries, then we are just plain not going to win
here. */
if (!node && entry_list_is_constrained(options) && consider_exit_family) {
/* still no? if we're using bridges or have strictentrynodes
* set, and our chosen exit is in the same family as all our
* bridges/entry guards, then be flexible about families. */
consider_exit_family = 0;
goto retry;
}
#endif
/* live_entry_guards may be empty below. Oh well, we tried. */
}
choose_and_finish:
if (entry_list_is_constrained(options)) {
/* We need to weight by bandwidth, because our bridges or entryguards
* were not already selected proportional to their bandwidth. */
node = node_sl_choose_by_bandwidth(live_entry_guards, WEIGHT_FOR_GUARD);
} else {
/* We choose uniformly at random here, because choose_good_entry_server()
* already weights its choices by bandwidth, so we don't want to
* *double*-weight our guard selection. */
node = smartlist_choose(live_entry_guards);
}
smartlist_free(live_entry_guards);
smartlist_free(exit_family);
return node;
}
/** Parse <b>state</b> and learn about the entry guards it describes.
* If <b>set</b> is true, and there are no errors, replace the global
* entry_list with what we find.
* On success, return 0. On failure, alloc into *<b>msg</b> a string
* describing the error, and return -1.
*/
int
entry_guards_parse_state(or_state_t *state, int set, char **msg)
{
entry_guard_t *node = NULL;
smartlist_t *new_entry_guards = smartlist_new();
config_line_t *line;
time_t now = time(NULL);
const char *state_version = state->TorVersion;
digestmap_t *added_by = digestmap_new();
*msg = NULL;
for (line = state->EntryGuards; line; line = line->next) {
if (!strcasecmp(line->key, "EntryGuard")) {
smartlist_t *args = smartlist_new();
node = tor_malloc_zero(sizeof(entry_guard_t));
/* all entry guards on disk have been contacted */
node->made_contact = 1;
smartlist_add(new_entry_guards, node);
smartlist_split_string(args, line->value, " ",
SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
if (smartlist_len(args)<2) {
*msg = tor_strdup("Unable to parse entry nodes: "
"Too few arguments to EntryGuard");
} else if (!is_legal_nickname(smartlist_get(args,0))) {
*msg = tor_strdup("Unable to parse entry nodes: "
"Bad nickname for EntryGuard");
} else {
strlcpy(node->nickname, smartlist_get(args,0), MAX_NICKNAME_LEN+1);
if (base16_decode(node->identity, DIGEST_LEN, smartlist_get(args,1),
strlen(smartlist_get(args,1)))<0) {
*msg = tor_strdup("Unable to parse entry nodes: "
"Bad hex digest for EntryGuard");
}
}
if (smartlist_len(args) >= 3) {
const char *is_cache = smartlist_get(args, 2);
if (!strcasecmp(is_cache, "DirCache")) {
node->is_dir_cache = 1;
} else if (!strcasecmp(is_cache, "NoDirCache")) {
node->is_dir_cache = 0;
} else {
log_warn(LD_CONFIG, "Bogus third argument to EntryGuard line: %s",
escaped(is_cache));
}
}
SMARTLIST_FOREACH(args, char*, cp, tor_free(cp));
smartlist_free(args);
if (*msg)
break;
} else if (!strcasecmp(line->key, "EntryGuardDownSince") ||
!strcasecmp(line->key, "EntryGuardUnlistedSince")) {
time_t when;
time_t last_try = 0;
if (!node) {
*msg = tor_strdup("Unable to parse entry nodes: "
"EntryGuardDownSince/UnlistedSince without EntryGuard");
break;
}
if (parse_iso_time(line->value, &when)<0) {
*msg = tor_strdup("Unable to parse entry nodes: "
"Bad time in EntryGuardDownSince/UnlistedSince");
break;
}
if (when > now) {
/* It's a bad idea to believe info in the future: you can wind
* up with timeouts that aren't allowed to happen for years. */
continue;
}
if (strlen(line->value) >= ISO_TIME_LEN+ISO_TIME_LEN+1) {
/* ignore failure */
(void) parse_iso_time(line->value+ISO_TIME_LEN+1, &last_try);
}
if (!strcasecmp(line->key, "EntryGuardDownSince")) {
node->unreachable_since = when;
node->last_attempted = last_try;
} else {
node->bad_since = when;
}
} else if (!strcasecmp(line->key, "EntryGuardAddedBy")) {
char d[DIGEST_LEN];
/* format is digest version date */
if (strlen(line->value) < HEX_DIGEST_LEN+1+1+1+ISO_TIME_LEN) {
log_warn(LD_BUG, "EntryGuardAddedBy line is not long enough.");
continue;
}
if (base16_decode(d, sizeof(d), line->value, HEX_DIGEST_LEN)<0 ||
line->value[HEX_DIGEST_LEN] != ' ') {
log_warn(LD_BUG, "EntryGuardAddedBy line %s does not begin with "
"hex digest", escaped(line->value));
continue;
}
digestmap_set(added_by, d, tor_strdup(line->value+HEX_DIGEST_LEN+1));
} else if (!strcasecmp(line->key, "EntryGuardPathUseBias")) {
const or_options_t *options = get_options();
double use_cnt, success_cnt;
if (!node) {
*msg = tor_strdup("Unable to parse entry nodes: "
"EntryGuardPathUseBias without EntryGuard");
break;
}
if (tor_sscanf(line->value, "%lf %lf",
&use_cnt, &success_cnt) != 2) {
log_info(LD_GENERAL, "Malformed path use bias line for node %s",
node->nickname);
continue;
}
if (use_cnt < success_cnt) {
int severity = LOG_INFO;
/* If this state file was written by a Tor that would have
* already fixed it, then the overcounting bug is still there.. */
if (tor_version_as_new_as(state_version, "0.2.4.13-alpha")) {
severity = LOG_NOTICE;
}
log_fn(severity, LD_BUG,
"State file contains unexpectedly high usage success "
"counts %lf/%lf for Guard %s ($%s)",
success_cnt, use_cnt,
node->nickname, hex_str(node->identity, DIGEST_LEN));
success_cnt = use_cnt;
}
node->use_attempts = use_cnt;
node->use_successes = success_cnt;
log_info(LD_GENERAL, "Read %f/%f path use bias for node %s",
node->use_successes, node->use_attempts, node->nickname);
/* Note: We rely on the < comparison here to allow us to set a 0
* rate and disable the feature entirely. If refactoring, don't
* change to <= */
if (pathbias_get_use_success_count(node)/node->use_attempts
< pathbias_get_extreme_use_rate(options) &&
pathbias_get_dropguards(options)) {
node->path_bias_disabled = 1;
log_info(LD_GENERAL,
"Path use bias is too high (%f/%f); disabling node %s",
node->circ_successes, node->circ_attempts, node->nickname);
}
} else if (!strcasecmp(line->key, "EntryGuardPathBias")) {
const or_options_t *options = get_options();
double hop_cnt, success_cnt, timeouts, collapsed, successful_closed,
unusable;
if (!node) {
*msg = tor_strdup("Unable to parse entry nodes: "
"EntryGuardPathBias without EntryGuard");
break;
}
/* First try 3 params, then 2. */
/* In the long run: circuit_success ~= successful_circuit_close +
* collapsed_circuits +
* unusable_circuits */
if (tor_sscanf(line->value, "%lf %lf %lf %lf %lf %lf",
&hop_cnt, &success_cnt, &successful_closed,
&collapsed, &unusable, &timeouts) != 6) {
int old_success, old_hops;
if (tor_sscanf(line->value, "%u %u", &old_success, &old_hops) != 2) {
continue;
}
log_info(LD_GENERAL, "Reading old-style EntryGuardPathBias %s",
escaped(line->value));
success_cnt = old_success;
successful_closed = old_success;
hop_cnt = old_hops;
timeouts = 0;
collapsed = 0;
unusable = 0;
}
if (hop_cnt < success_cnt) {
int severity = LOG_INFO;
/* If this state file was written by a Tor that would have
* already fixed it, then the overcounting bug is still there.. */
if (tor_version_as_new_as(state_version, "0.2.4.13-alpha")) {
severity = LOG_NOTICE;
}
log_fn(severity, LD_BUG,
"State file contains unexpectedly high success counts "
"%lf/%lf for Guard %s ($%s)",
success_cnt, hop_cnt,
node->nickname, hex_str(node->identity, DIGEST_LEN));
success_cnt = hop_cnt;
}
node->circ_attempts = hop_cnt;
node->circ_successes = success_cnt;
node->successful_circuits_closed = successful_closed;
node->timeouts = timeouts;
node->collapsed_circuits = collapsed;
node->unusable_circuits = unusable;
log_info(LD_GENERAL, "Read %f/%f path bias for node %s",
node->circ_successes, node->circ_attempts, node->nickname);
/* Note: We rely on the < comparison here to allow us to set a 0
* rate and disable the feature entirely. If refactoring, don't
* change to <= */
if (pathbias_get_close_success_count(node)/node->circ_attempts
< pathbias_get_extreme_rate(options) &&
pathbias_get_dropguards(options)) {
node->path_bias_disabled = 1;
log_info(LD_GENERAL,
"Path bias is too high (%f/%f); disabling node %s",
node->circ_successes, node->circ_attempts, node->nickname);
}
} else {
log_warn(LD_BUG, "Unexpected key %s", line->key);
}
}
SMARTLIST_FOREACH_BEGIN(new_entry_guards, entry_guard_t *, e) {
char *sp;
char *val = digestmap_get(added_by, e->identity);
if (val && (sp = strchr(val, ' '))) {
time_t when;
*sp++ = '\0';
if (parse_iso_time(sp, &when)<0) {
log_warn(LD_BUG, "Can't read time %s in EntryGuardAddedBy", sp);
} else {
e->chosen_by_version = tor_strdup(val);
e->chosen_on_date = when;
}
} else {
if (state_version) {
e->chosen_by_version = tor_strdup(state_version);
e->chosen_on_date = time(NULL) - crypto_rand_int(3600*24*30);
}
}
if (e->path_bias_disabled && !e->bad_since)
e->bad_since = time(NULL);
}
SMARTLIST_FOREACH_END(e);
if (*msg || !set) {
SMARTLIST_FOREACH(new_entry_guards, entry_guard_t *, e,
entry_guard_free(e));
smartlist_free(new_entry_guards);
} else { /* !err && set */
if (entry_guards) {
SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e,
entry_guard_free(e));
smartlist_free(entry_guards);
}
entry_guards = new_entry_guards;
entry_guards_dirty = 0;
/* XXX024 hand new_entry_guards to this func, and move it up a
* few lines, so we don't have to re-dirty it */
if (remove_obsolete_entry_guards(now))
entry_guards_dirty = 1;
update_node_guard_status();
}
digestmap_free(added_by, tor_free_);
return *msg ? -1 : 0;
}
/** Our list of entry guards has changed, or some element of one
* of our entry guards has changed. Write the changes to disk within
* the next few minutes.
*/
void
entry_guards_changed(void)
{
time_t when;
entry_guards_dirty = 1;
/* or_state_save() will call entry_guards_update_state(). */
when = get_options()->AvoidDiskWrites ? time(NULL) + 3600 : time(NULL)+600;
or_state_mark_dirty(get_or_state(), when);
}
/** If the entry guard info has not changed, do nothing and return.
* Otherwise, free the EntryGuards piece of <b>state</b> and create
* a new one out of the global entry_guards list, and then mark
* <b>state</b> dirty so it will get saved to disk.
*/
void
entry_guards_update_state(or_state_t *state)
{
config_line_t **next, *line;
if (! entry_guards_dirty)
return;
config_free_lines(state->EntryGuards);
next = &state->EntryGuards;
*next = NULL;
if (!entry_guards)
entry_guards = smartlist_new();
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
char dbuf[HEX_DIGEST_LEN+1];
if (!e->made_contact)
continue; /* don't write this one to disk */
*next = line = tor_malloc_zero(sizeof(config_line_t));
line->key = tor_strdup("EntryGuard");
base16_encode(dbuf, sizeof(dbuf), e->identity, DIGEST_LEN);
tor_asprintf(&line->value, "%s %s %sDirCache", e->nickname, dbuf,
e->is_dir_cache ? "" : "No");
next = &(line->next);
if (e->unreachable_since) {
*next = line = tor_malloc_zero(sizeof(config_line_t));
line->key = tor_strdup("EntryGuardDownSince");
line->value = tor_malloc(ISO_TIME_LEN+1+ISO_TIME_LEN+1);
format_iso_time(line->value, e->unreachable_since);
if (e->last_attempted) {
line->value[ISO_TIME_LEN] = ' ';
format_iso_time(line->value+ISO_TIME_LEN+1, e->last_attempted);
}
next = &(line->next);
}
if (e->bad_since) {
*next = line = tor_malloc_zero(sizeof(config_line_t));
line->key = tor_strdup("EntryGuardUnlistedSince");
line->value = tor_malloc(ISO_TIME_LEN+1);
format_iso_time(line->value, e->bad_since);
next = &(line->next);
}
if (e->chosen_on_date && e->chosen_by_version &&
!strchr(e->chosen_by_version, ' ')) {
char d[HEX_DIGEST_LEN+1];
char t[ISO_TIME_LEN+1];
*next = line = tor_malloc_zero(sizeof(config_line_t));
line->key = tor_strdup("EntryGuardAddedBy");
base16_encode(d, sizeof(d), e->identity, DIGEST_LEN);
format_iso_time(t, e->chosen_on_date);
tor_asprintf(&line->value, "%s %s %s",
d, e->chosen_by_version, t);
next = &(line->next);
}
if (e->circ_attempts > 0) {
*next = line = tor_malloc_zero(sizeof(config_line_t));
line->key = tor_strdup("EntryGuardPathBias");
/* In the long run: circuit_success ~= successful_circuit_close +
* collapsed_circuits +
* unusable_circuits */
tor_asprintf(&line->value, "%f %f %f %f %f %f",
e->circ_attempts, e->circ_successes,
pathbias_get_close_success_count(e),
e->collapsed_circuits,
e->unusable_circuits, e->timeouts);
next = &(line->next);
}
if (e->use_attempts > 0) {
*next = line = tor_malloc_zero(sizeof(config_line_t));
line->key = tor_strdup("EntryGuardPathUseBias");
tor_asprintf(&line->value, "%f %f",
e->use_attempts,
pathbias_get_use_success_count(e));
next = &(line->next);
}
} SMARTLIST_FOREACH_END(e);
if (!get_options()->AvoidDiskWrites)
or_state_mark_dirty(get_or_state(), 0);
entry_guards_dirty = 0;
}
/** If <b>question</b> is the string "entry-guards", then dump
* to *<b>answer</b> a newly allocated string describing all of
* the nodes in the global entry_guards list. See control-spec.txt
* for details.
* For backward compatibility, we also handle the string "helper-nodes".
* */
int
getinfo_helper_entry_guards(control_connection_t *conn,
const char *question, char **answer,
const char **errmsg)
{
(void) conn;
(void) errmsg;
if (!strcmp(question,"entry-guards") ||
!strcmp(question,"helper-nodes")) {
smartlist_t *sl = smartlist_new();
char tbuf[ISO_TIME_LEN+1];
char nbuf[MAX_VERBOSE_NICKNAME_LEN+1];
if (!entry_guards)
entry_guards = smartlist_new();
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
const char *status = NULL;
time_t when = 0;
const node_t *node;
if (!e->made_contact) {
status = "never-connected";
} else if (e->bad_since) {
when = e->bad_since;
status = "unusable";
} else {
status = "up";
}
node = node_get_by_id(e->identity);
if (node) {
node_get_verbose_nickname(node, nbuf);
} else {
nbuf[0] = '$';
base16_encode(nbuf+1, sizeof(nbuf)-1, e->identity, DIGEST_LEN);
/* e->nickname field is not very reliable if we don't know about
* this router any longer; don't include it. */
}
if (when) {
format_iso_time(tbuf, when);
smartlist_add_asprintf(sl, "%s %s %s\n", nbuf, status, tbuf);
} else {
smartlist_add_asprintf(sl, "%s %s\n", nbuf, status);
}
} SMARTLIST_FOREACH_END(e);
*answer = smartlist_join_strings(sl, "", 0, NULL);
SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
smartlist_free(sl);
}
return 0;
}
/** A list of configured bridges. Whenever we actually get a descriptor
* for one, we add it as an entry guard. Note that the order of bridges
* in this list does not necessarily correspond to the order of bridges
* in the torrc. */
static smartlist_t *bridge_list = NULL;
/** Mark every entry of the bridge list to be removed on our next call to
* sweep_bridge_list unless it has first been un-marked. */
void
mark_bridge_list(void)
{
if (!bridge_list)
bridge_list = smartlist_new();
SMARTLIST_FOREACH(bridge_list, bridge_info_t *, b,
b->marked_for_removal = 1);
}
/** Remove every entry of the bridge list that was marked with
* mark_bridge_list if it has not subsequently been un-marked. */
void
sweep_bridge_list(void)
{
if (!bridge_list)
bridge_list = smartlist_new();
SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b) {
if (b->marked_for_removal) {
SMARTLIST_DEL_CURRENT(bridge_list, b);
bridge_free(b);
}
} SMARTLIST_FOREACH_END(b);
}
/** Initialize the bridge list to empty, creating it if needed. */
static void
clear_bridge_list(void)
{
if (!bridge_list)
bridge_list = smartlist_new();
SMARTLIST_FOREACH(bridge_list, bridge_info_t *, b, bridge_free(b));
smartlist_clear(bridge_list);
}
/** Free the bridge <b>bridge</b>. */
static void
bridge_free(bridge_info_t *bridge)
{
if (!bridge)
return;
tor_free(bridge->transport_name);
if (bridge->socks_args) {
SMARTLIST_FOREACH(bridge->socks_args, char*, s, tor_free(s));
smartlist_free(bridge->socks_args);
}
tor_free(bridge);
}
/** If we have a bridge configured whose digest matches <b>digest</b>, or a
* bridge with no known digest whose address matches any of the
* tor_addr_port_t's in <b>orports</b>, return that bridge. Else return
* NULL. */
static bridge_info_t *
get_configured_bridge_by_orports_digest(const char *digest,
const smartlist_t *orports)
{
if (!bridge_list)
return NULL;
SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge)
{
if (tor_digest_is_zero(bridge->identity)) {
SMARTLIST_FOREACH_BEGIN(orports, tor_addr_port_t *, ap)
{
if (tor_addr_compare(&bridge->addr, &ap->addr, CMP_EXACT) == 0 &&
bridge->port == ap->port)
return bridge;
}
SMARTLIST_FOREACH_END(ap);
}
if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN))
return bridge;
}
SMARTLIST_FOREACH_END(bridge);
return NULL;
}
/** If we have a bridge configured whose digest matches <b>digest</b>, or a
* bridge with no known digest whose address matches <b>addr</b>:<b>/port</b>,
* return that bridge. Else return NULL. If <b>digest</b> is NULL, check for
* address/port matches only. */
static bridge_info_t *
get_configured_bridge_by_addr_port_digest(const tor_addr_t *addr,
uint16_t port,
const char *digest)
{
if (!bridge_list)
return NULL;
SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge)
{
if ((tor_digest_is_zero(bridge->identity) || digest == NULL) &&
!tor_addr_compare(&bridge->addr, addr, CMP_EXACT) &&
bridge->port == port)
return bridge;
if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN))
return bridge;
}
SMARTLIST_FOREACH_END(bridge);
return NULL;
}
/** Wrapper around get_configured_bridge_by_addr_port_digest() to look
* it up via router descriptor <b>ri</b>. */
static bridge_info_t *
get_configured_bridge_by_routerinfo(const routerinfo_t *ri)
{
bridge_info_t *bi = NULL;
smartlist_t *orports = router_get_all_orports(ri);
bi = get_configured_bridge_by_orports_digest(ri->cache_info.identity_digest,
orports);
SMARTLIST_FOREACH(orports, tor_addr_port_t *, p, tor_free(p));
smartlist_free(orports);
return bi;
}
/** Return 1 if <b>ri</b> is one of our known bridges, else 0. */
int
routerinfo_is_a_configured_bridge(const routerinfo_t *ri)
{
return get_configured_bridge_by_routerinfo(ri) ? 1 : 0;
}
/** Return 1 if <b>node</b> is one of our configured bridges, else 0. */
int
node_is_a_configured_bridge(const node_t *node)
{
int retval = 0;
smartlist_t *orports = node_get_all_orports(node);
retval = get_configured_bridge_by_orports_digest(node->identity,
orports) != NULL;
SMARTLIST_FOREACH(orports, tor_addr_port_t *, p, tor_free(p));
smartlist_free(orports);
return retval;
}
/** We made a connection to a router at <b>addr</b>:<b>port</b>
* without knowing its digest. Its digest turned out to be <b>digest</b>.
* If it was a bridge, and we still don't know its digest, record it.
*/
void
learned_router_identity(const tor_addr_t *addr, uint16_t port,
const char *digest)
{
bridge_info_t *bridge =
get_configured_bridge_by_addr_port_digest(addr, port, digest);
if (bridge && tor_digest_is_zero(bridge->identity)) {
char *transport_info = NULL;
const char *transport_name =
find_transport_name_by_bridge_addrport(addr, port);
if (transport_name)
tor_asprintf(&transport_info, " (with transport '%s')", transport_name);
memcpy(bridge->identity, digest, DIGEST_LEN);
log_notice(LD_DIR, "Learned fingerprint %s for bridge %s%s.",
hex_str(digest, DIGEST_LEN), fmt_addrport(addr, port),
transport_info ? transport_info : "");
tor_free(transport_info);
}
}
/** Return true if <b>bridge</b> has the same identity digest as
* <b>digest</b>. If <b>digest</b> is NULL, it matches
* bridges with unspecified identity digests. */
static int
bridge_has_digest(const bridge_info_t *bridge, const char *digest)
{
if (digest)
return tor_memeq(digest, bridge->identity, DIGEST_LEN);
else
return tor_digest_is_zero(bridge->identity);
}
/** We are about to add a new bridge at <b>addr</b>:<b>port</b>, with optional
* <b>digest</b> and <b>transport_name</b>. Mark for removal any previously
* existing bridge with the same address and port, and warn the user as
* appropriate.
*/
static void
bridge_resolve_conflicts(const tor_addr_t *addr, uint16_t port,
const char *digest, const char *transport_name)
{
/* Iterate the already-registered bridge list:
If you find a bridge with the same adress and port, mark it for
removal. It doesn't make sense to have two active bridges with
the same IP:PORT. If the bridge in question has a different
digest or transport than <b>digest</b>/<b>transport_name</b>,
it's probably a misconfiguration and we should warn the user.
*/
SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) {
if (bridge->marked_for_removal)
continue;
if (tor_addr_eq(&bridge->addr, addr) && (bridge->port == port)) {
bridge->marked_for_removal = 1;
if (!bridge_has_digest(bridge, digest) ||
strcmp_opt(bridge->transport_name, transport_name)) {
/* warn the user */
char *bridge_description_new, *bridge_description_old;
tor_asprintf(&bridge_description_new, "%s:%s:%s",
fmt_addrport(addr, port),
digest ? hex_str(digest, DIGEST_LEN) : "",
transport_name ? transport_name : "");
tor_asprintf(&bridge_description_old, "%s:%s:%s",
fmt_addrport(&bridge->addr, bridge->port),
tor_digest_is_zero(bridge->identity) ?
"" : hex_str(bridge->identity,DIGEST_LEN),
bridge->transport_name ? bridge->transport_name : "");
log_warn(LD_GENERAL,"Tried to add bridge '%s', but we found a conflict"
" with the already registered bridge '%s'. We will discard"
" the old bridge and keep '%s'. If this is not what you"
" wanted, please change your configuration file accordingly.",
bridge_description_new, bridge_description_old,
bridge_description_new);
tor_free(bridge_description_new);
tor_free(bridge_description_old);
}
}
} SMARTLIST_FOREACH_END(bridge);
}
/** Return True if we have a bridge that uses a transport with name
* <b>transport_name</b>. */
int
transport_is_needed(const char *transport_name)
{
if (!bridge_list)
return 0;
SMARTLIST_FOREACH_BEGIN(bridge_list, const bridge_info_t *, bridge) {
if (bridge->transport_name &&
!strcmp(bridge->transport_name, transport_name))
return 1;
} SMARTLIST_FOREACH_END(bridge);
return 0;
}
/** Register the bridge information in <b>bridge_line</b> to the
* bridge subsystem. Steals reference of <b>bridge_line</b>. */
void
bridge_add_from_config(bridge_line_t *bridge_line)
{
bridge_info_t *b;
{ /* Log the bridge we are about to register: */
log_debug(LD_GENERAL, "Registering bridge at %s (transport: %s) (%s)",
fmt_addrport(&bridge_line->addr, bridge_line->port),
bridge_line->transport_name ?
bridge_line->transport_name : "no transport",
tor_digest_is_zero(bridge_line->digest) ?
"no key listed" : hex_str(bridge_line->digest, DIGEST_LEN));
if (bridge_line->socks_args) { /* print socks arguments */
int i = 0;
tor_assert(smartlist_len(bridge_line->socks_args) > 0);
log_debug(LD_GENERAL, "Bridge uses %d SOCKS arguments:",
smartlist_len(bridge_line->socks_args));
SMARTLIST_FOREACH(bridge_line->socks_args, const char *, arg,
log_debug(LD_CONFIG, "%d: %s", ++i, arg));
}
}
bridge_resolve_conflicts(&bridge_line->addr,
bridge_line->port,
bridge_line->digest,
bridge_line->transport_name);
b = tor_malloc_zero(sizeof(bridge_info_t));
tor_addr_copy(&b->addr, &bridge_line->addr);
b->port = bridge_line->port;
memcpy(b->identity, bridge_line->digest, DIGEST_LEN);
if (bridge_line->transport_name)
b->transport_name = bridge_line->transport_name;
b->fetch_status.schedule = DL_SCHED_BRIDGE;
b->socks_args = bridge_line->socks_args;
if (!bridge_list)
bridge_list = smartlist_new();
tor_free(bridge_line); /* Deallocate bridge_line now. */
smartlist_add(bridge_list, b);
}
/** Return true iff <b>routerset</b> contains the bridge <b>bridge</b>. */
static int
routerset_contains_bridge(const routerset_t *routerset,
const bridge_info_t *bridge)
{
int result;
extend_info_t *extinfo;
tor_assert(bridge);
if (!routerset)
return 0;
extinfo = extend_info_new(
NULL, bridge->identity, NULL, NULL, &bridge->addr, bridge->port);
result = routerset_contains_extendinfo(routerset, extinfo);
extend_info_free(extinfo);
return result;
}
/** If <b>digest</b> is one of our known bridges, return it. */
static bridge_info_t *
find_bridge_by_digest(const char *digest)
{
SMARTLIST_FOREACH(bridge_list, bridge_info_t *, bridge,
{
if (tor_memeq(bridge->identity, digest, DIGEST_LEN))
return bridge;
});
return NULL;
}
/** Given the <b>addr</b> and <b>port</b> of a bridge, if that bridge
* supports a pluggable transport, return its name. Otherwise, return
* NULL. */
const char *
find_transport_name_by_bridge_addrport(const tor_addr_t *addr, uint16_t port)
{
if (!bridge_list)
return NULL;
SMARTLIST_FOREACH_BEGIN(bridge_list, const bridge_info_t *, bridge) {
if (tor_addr_eq(&bridge->addr, addr) &&
(bridge->port == port))
return bridge->transport_name;
} SMARTLIST_FOREACH_END(bridge);
return NULL;
}
/** If <b>addr</b> and <b>port</b> match the address and port of a
* bridge of ours that uses pluggable transports, place its transport
* in <b>transport</b>.
*
* Return 0 on success (found a transport, or found a bridge with no
* transport, or found no bridge); return -1 if we should be using a
* transport, but the transport could not be found.
*/
int
get_transport_by_bridge_addrport(const tor_addr_t *addr, uint16_t port,
const transport_t **transport)
{
*transport = NULL;
if (!bridge_list)
return 0;
SMARTLIST_FOREACH_BEGIN(bridge_list, const bridge_info_t *, bridge) {
if (tor_addr_eq(&bridge->addr, addr) &&
(bridge->port == port)) { /* bridge matched */
if (bridge->transport_name) { /* it also uses pluggable transports */
*transport = transport_get_by_name(bridge->transport_name);
if (*transport == NULL) { /* it uses pluggable transports, but
the transport could not be found! */
return -1;
}
return 0;
} else { /* bridge matched, but it doesn't use transports. */
break;
}
}
} SMARTLIST_FOREACH_END(bridge);
*transport = NULL;
return 0;
}
/** Return a smartlist containing all the SOCKS arguments that we
* should pass to the SOCKS proxy. */
const smartlist_t *
get_socks_args_by_bridge_addrport(const tor_addr_t *addr, uint16_t port)
{
bridge_info_t *bridge = get_configured_bridge_by_addr_port_digest(addr,
port,
NULL);
return bridge ? bridge->socks_args : NULL;
}
/** We need to ask <b>bridge</b> for its server descriptor. */
static void
launch_direct_bridge_descriptor_fetch(bridge_info_t *bridge)
{
const or_options_t *options = get_options();
if (connection_get_by_type_addr_port_purpose(
CONN_TYPE_DIR, &bridge->addr, bridge->port,
DIR_PURPOSE_FETCH_SERVERDESC))
return; /* it's already on the way */
if (routerset_contains_bridge(options->ExcludeNodes, bridge)) {
download_status_mark_impossible(&bridge->fetch_status);
log_warn(LD_APP, "Not using bridge at %s: it is in ExcludeNodes.",
safe_str_client(fmt_and_decorate_addr(&bridge->addr)));
return;
}
directory_initiate_command(&bridge->addr,
bridge->port, 0/*no dirport*/,
bridge->identity,
DIR_PURPOSE_FETCH_SERVERDESC,
ROUTER_PURPOSE_BRIDGE,
DIRIND_ONEHOP, "authority.z", NULL, 0, 0);
}
/** Fetching the bridge descriptor from the bridge authority returned a
* "not found". Fall back to trying a direct fetch. */
void
retry_bridge_descriptor_fetch_directly(const char *digest)
{
bridge_info_t *bridge = find_bridge_by_digest(digest);
if (!bridge)
return; /* not found? oh well. */
launch_direct_bridge_descriptor_fetch(bridge);
}
/** For each bridge in our list for which we don't currently have a
* descriptor, fetch a new copy of its descriptor -- either directly
* from the bridge or via a bridge authority. */
void
fetch_bridge_descriptors(const or_options_t *options, time_t now)
{
int num_bridge_auths = get_n_authorities(BRIDGE_DIRINFO);
int ask_bridge_directly;
int can_use_bridge_authority;
if (!bridge_list)
return;
/* If we still have unconfigured managed proxies, don't go and
connect to a bridge. */
if (pt_proxies_configuration_pending())
return;
SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge)
{
if (!download_status_is_ready(&bridge->fetch_status, now,
IMPOSSIBLE_TO_DOWNLOAD))
continue; /* don't bother, no need to retry yet */
if (routerset_contains_bridge(options->ExcludeNodes, bridge)) {
download_status_mark_impossible(&bridge->fetch_status);
log_warn(LD_APP, "Not using bridge at %s: it is in ExcludeNodes.",
safe_str_client(fmt_and_decorate_addr(&bridge->addr)));
continue;
}
/* schedule another fetch as if this one will fail, in case it does */
download_status_failed(&bridge->fetch_status, 0);
can_use_bridge_authority = !tor_digest_is_zero(bridge->identity) &&
num_bridge_auths;
ask_bridge_directly = !can_use_bridge_authority ||
!options->UpdateBridgesFromAuthority;
log_debug(LD_DIR, "ask_bridge_directly=%d (%d, %d, %d)",
ask_bridge_directly, tor_digest_is_zero(bridge->identity),
!options->UpdateBridgesFromAuthority, !num_bridge_auths);
if (ask_bridge_directly &&
!fascist_firewall_allows_address_or(&bridge->addr, bridge->port)) {
log_notice(LD_DIR, "Bridge at '%s' isn't reachable by our "
"firewall policy. %s.",
fmt_addrport(&bridge->addr, bridge->port),
can_use_bridge_authority ?
"Asking bridge authority instead" : "Skipping");
if (can_use_bridge_authority)
ask_bridge_directly = 0;
else
continue;
}
if (ask_bridge_directly) {
/* we need to ask the bridge itself for its descriptor. */
launch_direct_bridge_descriptor_fetch(bridge);
} else {
/* We have a digest and we want to ask an authority. We could
* combine all the requests into one, but that may give more
* hints to the bridge authority than we want to give. */
char resource[10 + HEX_DIGEST_LEN];
memcpy(resource, "fp/", 3);
base16_encode(resource+3, HEX_DIGEST_LEN+1,
bridge->identity, DIGEST_LEN);
memcpy(resource+3+HEX_DIGEST_LEN, ".z", 3);
log_info(LD_DIR, "Fetching bridge info '%s' from bridge authority.",
resource);
directory_get_from_dirserver(DIR_PURPOSE_FETCH_SERVERDESC,
ROUTER_PURPOSE_BRIDGE, resource, 0);
}
}
SMARTLIST_FOREACH_END(bridge);
}
/** If our <b>bridge</b> is configured to be a different address than
* the bridge gives in <b>node</b>, rewrite the routerinfo
* we received to use the address we meant to use. Now we handle
* multihomed bridges better.
*/
static void
rewrite_node_address_for_bridge(const bridge_info_t *bridge, node_t *node)
{
/* XXXX move this function. */
/* XXXX overridden addresses should really live in the node_t, so that the
* routerinfo_t and the microdesc_t can be immutable. But we can only
* do that safely if we know that no function that connects to an OR
* does so through an address from any source other than node_get_addr().
*/
tor_addr_t addr;
if (node->ri) {
routerinfo_t *ri = node->ri;
tor_addr_from_ipv4h(&addr, ri->addr);
if ((!tor_addr_compare(&bridge->addr, &addr, CMP_EXACT) &&
bridge->port == ri->or_port) ||
(!tor_addr_compare(&bridge->addr, &ri->ipv6_addr, CMP_EXACT) &&
bridge->port == ri->ipv6_orport)) {
/* they match, so no need to do anything */
} else {
if (tor_addr_family(&bridge->addr) == AF_INET) {
ri->addr = tor_addr_to_ipv4h(&bridge->addr);
ri->or_port = bridge->port;
log_info(LD_DIR,
"Adjusted bridge routerinfo for '%s' to match configured "
"address %s:%d.",
ri->nickname, fmt_addr32(ri->addr), ri->or_port);
} else if (tor_addr_family(&bridge->addr) == AF_INET6) {
tor_addr_copy(&ri->ipv6_addr, &bridge->addr);
ri->ipv6_orport = bridge->port;
log_info(LD_DIR,
"Adjusted bridge routerinfo for '%s' to match configured "
"address %s.",
ri->nickname, fmt_addrport(&ri->ipv6_addr, ri->ipv6_orport));
} else {
log_err(LD_BUG, "Address family not supported: %d.",
tor_addr_family(&bridge->addr));
return;
}
}
/* Mark which address to use based on which bridge_t we got. */
node->ipv6_preferred = (tor_addr_family(&bridge->addr) == AF_INET6 &&
!tor_addr_is_null(&node->ri->ipv6_addr));
/* XXXipv6 we lack support for falling back to another address for
the same relay, warn the user */
if (!tor_addr_is_null(&ri->ipv6_addr)) {
tor_addr_port_t ap;
node_get_pref_orport(node, &ap);
log_notice(LD_CONFIG,
"Bridge '%s' has both an IPv4 and an IPv6 address. "
"Will prefer using its %s address (%s).",
ri->nickname,
tor_addr_family(&ap.addr) == AF_INET6 ? "IPv6" : "IPv4",
fmt_addrport(&ap.addr, ap.port));
}
}
if (node->rs) {
routerstatus_t *rs = node->rs;
tor_addr_from_ipv4h(&addr, rs->addr);
if (!tor_addr_compare(&bridge->addr, &addr, CMP_EXACT) &&
bridge->port == rs->or_port) {
/* they match, so no need to do anything */
} else {
rs->addr = tor_addr_to_ipv4h(&bridge->addr);
rs->or_port = bridge->port;
log_info(LD_DIR,
"Adjusted bridge routerstatus for '%s' to match "
"configured address %s.",
rs->nickname, fmt_addrport(&bridge->addr, rs->or_port));
}
}
}
/** We just learned a descriptor for a bridge. See if that
* digest is in our entry guard list, and add it if not. */
void
learned_bridge_descriptor(routerinfo_t *ri, int from_cache)
{
tor_assert(ri);
tor_assert(ri->purpose == ROUTER_PURPOSE_BRIDGE);
if (get_options()->UseBridges) {
int first = !any_bridge_descriptors_known();
bridge_info_t *bridge = get_configured_bridge_by_routerinfo(ri);
time_t now = time(NULL);
router_set_status(ri->cache_info.identity_digest, 1);
if (bridge) { /* if we actually want to use this one */
node_t *node;
/* it's here; schedule its re-fetch for a long time from now. */
if (!from_cache)
download_status_reset(&bridge->fetch_status);
node = node_get_mutable_by_id(ri->cache_info.identity_digest);
tor_assert(node);
rewrite_node_address_for_bridge(bridge, node);
add_an_entry_guard(node, 1, 1, 0, 0);
log_notice(LD_DIR, "new bridge descriptor '%s' (%s): %s", ri->nickname,
from_cache ? "cached" : "fresh", router_describe(ri));
/* set entry->made_contact so if it goes down we don't drop it from
* our entry node list */
entry_guard_register_connect_status(ri->cache_info.identity_digest,
1, 0, now);
if (first)
routerlist_retry_directory_downloads(now);
}
}
}
/** Return 1 if any of our entry guards have descriptors that
* are marked with purpose 'bridge' and are running. Else return 0.
*
* We use this function to decide if we're ready to start building
* circuits through our bridges, or if we need to wait until the
* directory "server/authority" requests finish. */
int
any_bridge_descriptors_known(void)
{
tor_assert(get_options()->UseBridges);
return choose_random_entry(NULL) != NULL;
}
/** Return 1 if we have at least one descriptor for an entry guard
* (bridge or member of EntryNodes) and all descriptors we know are
* down. Else return 0. If <b>act</b> is 1, then mark the down guards
* up; else just observe and report. */
static int
entries_retry_helper(const or_options_t *options, int act)
{
const node_t *node;
int any_known = 0;
int any_running = 0;
int need_bridges = options->UseBridges != 0;
if (!entry_guards)
entry_guards = smartlist_new();
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
node = node_get_by_id(e->identity);
if (node && node_has_descriptor(node) &&
node_is_bridge(node) == need_bridges) {
any_known = 1;
if (node->is_running)
any_running = 1; /* some entry is both known and running */
else if (act) {
/* Mark all current connections to this OR as unhealthy, since
* otherwise there could be one that started 30 seconds
* ago, and in 30 seconds it will time out, causing us to mark
* the node down and undermine the retry attempt. We mark even
* the established conns, since if the network just came back
* we'll want to attach circuits to fresh conns. */
connection_or_set_bad_connections(node->identity, 1);
/* mark this entry node for retry */
router_set_status(node->identity, 1);
e->can_retry = 1;
e->bad_since = 0;
}
}
} SMARTLIST_FOREACH_END(e);
log_debug(LD_DIR, "%d: any_known %d, any_running %d",
act, any_known, any_running);
return any_known && !any_running;
}
/** Do we know any descriptors for our bridges / entrynodes, and are
* all the ones we have descriptors for down? */
int
entries_known_but_down(const or_options_t *options)
{
tor_assert(entry_list_is_constrained(options));
return entries_retry_helper(options, 0);
}
/** Mark all down known bridges / entrynodes up. */
void
entries_retry_all(const or_options_t *options)
{
tor_assert(entry_list_is_constrained(options));
entries_retry_helper(options, 1);
}
/** Return true if at least one of our bridges runs a Tor version that can
* provide microdescriptors to us. If not, we'll fall back to asking for
* full descriptors. */
int
any_bridge_supports_microdescriptors(void)
{
const node_t *node;
if (!get_options()->UseBridges || !entry_guards)
return 0;
SMARTLIST_FOREACH_BEGIN(entry_guards, entry_guard_t *, e) {
node = node_get_by_id(e->identity);
if (node && node->is_running &&
node_is_bridge(node) && node_is_a_configured_bridge(node) &&
node_understands_microdescriptors(node)) {
/* This is one of our current bridges, and we know enough about
* it to know that it will be able to answer our microdescriptor
* questions. */
return 1;
}
} SMARTLIST_FOREACH_END(e);
return 0;
}
/** Release all storage held by the list of entry guards and related
* memory structs. */
void
entry_guards_free_all(void)
{
if (entry_guards) {
SMARTLIST_FOREACH(entry_guards, entry_guard_t *, e,
entry_guard_free(e));
smartlist_free(entry_guards);
entry_guards = NULL;
}
clear_bridge_list();
smartlist_free(bridge_list);
bridge_list = NULL;
circuit_build_times_free_timeouts(get_circuit_build_times_mutable());
}
|