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
#![cfg_attr(docsrs, feature(doc_auto_cfg, doc_cfg))]
#![doc = include_str!("../README.md")]
// @@ begin lint list maintained by maint/add_warning @@
#![cfg_attr(not(ci_arti_stable), allow(renamed_and_removed_lints))]
#![cfg_attr(not(ci_arti_nightly), allow(unknown_lints))]
#![warn(missing_docs)]
#![warn(noop_method_call)]
#![warn(unreachable_pub)]
#![warn(clippy::all)]
#![deny(clippy::await_holding_lock)]
#![deny(clippy::cargo_common_metadata)]
#![deny(clippy::cast_lossless)]
#![deny(clippy::checked_conversions)]
#![warn(clippy::cognitive_complexity)]
#![deny(clippy::debug_assert_with_mut_call)]
#![deny(clippy::exhaustive_enums)]
#![deny(clippy::exhaustive_structs)]
#![deny(clippy::expl_impl_clone_on_copy)]
#![deny(clippy::fallible_impl_from)]
#![deny(clippy::implicit_clone)]
#![deny(clippy::large_stack_arrays)]
#![warn(clippy::manual_ok_or)]
#![deny(clippy::missing_docs_in_private_items)]
#![warn(clippy::needless_borrow)]
#![warn(clippy::needless_pass_by_value)]
#![warn(clippy::option_option)]
#![deny(clippy::print_stderr)]
#![deny(clippy::print_stdout)]
#![warn(clippy::rc_buffer)]
#![deny(clippy::ref_option_ref)]
#![warn(clippy::semicolon_if_nothing_returned)]
#![warn(clippy::trait_duplication_in_bounds)]
#![deny(clippy::unchecked_duration_subtraction)]
#![deny(clippy::unnecessary_wraps)]
#![warn(clippy::unseparated_literal_suffix)]
#![deny(clippy::unwrap_used)]
#![allow(clippy::let_unit_value)] // This can reasonably be done for explicitness
#![allow(clippy::uninlined_format_args)]
#![allow(clippy::significant_drop_in_scrutinee)] // arti/-/merge_requests/588/#note_2812945
#![allow(clippy::result_large_err)] // temporary workaround for arti#587
#![allow(clippy::needless_raw_string_hashes)] // complained-about code is fine, often best
//! <!-- @@ end lint list maintained by maint/add_warning @@ -->
// Glossary:
// Primary guard
// Sample
// confirmed
// filtered
use futures::channel::mpsc;
use futures::task::SpawnExt;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::net::SocketAddr;
use std::sync::{Arc, Mutex, Weak};
use std::time::{Duration, Instant, SystemTime};
#[cfg(feature = "bridge-client")]
use tor_error::internal;
use tor_linkspec::{OwnedChanTarget, OwnedCircTarget, RelayId, RelayIdSet};
use tor_netdir::NetDirProvider;
use tor_proto::ClockSkew;
use tor_units::BoundedInt32;
use tracing::{debug, info, trace, warn};
use tor_config::impl_standard_builder;
use tor_config::ReconfigureError;
use tor_config::{define_list_builder_accessors, define_list_builder_helper};
use tor_netdir::{params::NetParameters, NetDir, Relay};
use tor_persist::{DynStorageHandle, StateMgr};
use tor_rtcompat::Runtime;
#[cfg(feature = "bridge-client")]
pub mod bridge;
mod config;
mod daemon;
mod dirstatus;
mod err;
mod events;
pub mod fallback;
mod filter;
mod guard;
mod ids;
mod pending;
mod sample;
mod skew;
mod util;
#[cfg(feature = "vanguards")]
pub mod vanguards;
#[cfg(not(feature = "bridge-client"))]
#[path = "bridge_disabled.rs"]
pub mod bridge;
#[cfg(any(test, feature = "testing"))]
pub use config::testing::TestConfig;
#[cfg(test)]
use tor_async_utils::oneshot;
pub use config::GuardMgrConfig;
pub use err::{GuardMgrConfigError, GuardMgrError, PickGuardError};
pub use events::ClockSkewEvents;
pub use filter::GuardFilter;
pub use ids::FirstHopId;
pub use pending::{GuardMonitor, GuardStatus, GuardUsable};
pub use skew::SkewEstimate;
#[cfg(feature = "vanguards")]
#[cfg_attr(docsrs, doc(cfg(feature = "vanguards")))]
pub use vanguards::VanguardMgrError;
use pending::{PendingRequest, RequestId};
use sample::{GuardSet, Universe, UniverseRef};
use crate::ids::{FirstHopIdInner, GuardId};
/// A "guard manager" that selects and remembers a persistent set of
/// guard nodes.
///
/// This is a "handle"; clones of it share state.
#[derive(Clone)]
pub struct GuardMgr<R: Runtime> {
/// An asynchronous runtime object.
///
/// GuardMgr uses this runtime for timing, timeouts, and spawning
/// tasks.
runtime: R,
/// Internal state for the guard manager.
inner: Arc<Mutex<GuardMgrInner>>,
}
/// Helper type that holds the data used by a [`GuardMgr`].
///
/// This would just be a [`GuardMgr`], except that it needs to sit inside
/// a `Mutex` and get accessed by daemon tasks.
struct GuardMgrInner {
/// Last time when marked all of our primary guards as retriable.
///
/// We keep track of this time so that we can rate-limit
/// these attempts.
last_primary_retry_time: Instant,
/// Persistent guard manager state.
///
/// This object remembers one or more persistent set of guards that we can
/// use, along with their relative priorities and statuses.
guards: GuardSets,
/// The current filter that we're using to decide which guards are
/// supported.
//
// TODO: This field is duplicated in the current active [`GuardSet`]; we
// should fix that.
filter: GuardFilter,
/// Configuration values derived from the consensus parameters.
///
/// This is updated whenever the consensus parameters change.
params: GuardParams,
/// A mpsc channel, used to tell the task running in
/// [`daemon::report_status_events`] about a new event to monitor.
///
/// This uses an `UnboundedSender` so that we don't have to await
/// while sending the message, which in turn allows the GuardMgr
/// API to be simpler. The risk, however, is that there's no
/// backpressure in the event that the task running
/// [`daemon::report_status_events`] fails to read from this
/// channel.
ctrl: mpsc::UnboundedSender<daemon::Msg>,
/// Information about guards that we've given out, but where we have
/// not yet heard whether the guard was successful.
///
/// Upon leaning whether the guard was successful, the pending
/// requests in this map may be either moved to `waiting`, or
/// discarded.
///
/// There can be multiple pending requests corresponding to the
/// same guard.
pending: HashMap<RequestId, PendingRequest>,
/// A list of pending requests for which we have heard that the
/// guard was successful, but we have not yet decided whether the
/// circuit may be used.
///
/// There can be multiple waiting requests corresponding to the
/// same guard.
waiting: Vec<PendingRequest>,
/// A list of fallback directories used to access the directory system
/// when no other directory information is yet known.
fallbacks: fallback::FallbackState,
/// Location in which to store persistent state.
storage: DynStorageHandle<GuardSets>,
/// A sender object to publish changes in our estimated clock skew.
send_skew: postage::watch::Sender<Option<SkewEstimate>>,
/// A receiver object to hand out to observers who want to know about
/// changes in our estimated clock skew.
recv_skew: events::ClockSkewEvents,
/// A netdir provider that we can use for adding new guards when
/// insufficient guards are available.
///
/// This has to be an Option so it can be initialized from None: at the
/// time a GuardMgr is created, there is no NetDirProvider for it to use.
netdir_provider: Option<Weak<dyn NetDirProvider>>,
/// A netdir provider that we can use for discovering bridge descriptors.
///
/// This has to be an Option so it can be initialized from None: at the time
/// a GuardMgr is created, there is no BridgeDescProvider for it to use.
#[cfg(feature = "bridge-client")]
bridge_desc_provider: Option<Weak<dyn bridge::BridgeDescProvider>>,
/// A list of the bridges that we are configured to use, or "None" if we are
/// not configured to use bridges.
#[cfg(feature = "bridge-client")]
configured_bridges: Option<Arc<[bridge::BridgeConfig]>>,
}
/// A selector that tells us which [`GuardSet`] of several is currently in use.
#[derive(Clone, Debug, Default, Eq, PartialEq, Ord, PartialOrd, strum::EnumIter)]
enum GuardSetSelector {
/// The default guard set is currently in use: that's the one that we use
/// when we have no filter installed, or the filter permits most of the
/// guards on the network.
#[default]
Default,
/// A "restrictive" guard set is currently in use: that's the one that we
/// use when we have a filter that excludes a large fraction of the guards
/// on the network.
Restricted,
/// The "bridges" guard set is currently in use: we are selecting our guards
/// from among the universe of configured bridges.
#[cfg(feature = "bridge-client")]
Bridges,
}
/// Describes the [`Universe`] that a guard sample should take its guards from.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum UniverseType {
/// Take information from the network directory.
NetDir,
/// Take information from the configured bridges.
#[cfg(feature = "bridge-client")]
BridgeSet,
}
impl GuardSetSelector {
/// Return a description of which [`Universe`] this guard sample should take
/// its guards from.
fn universe_type(&self) -> UniverseType {
match self {
GuardSetSelector::Default | GuardSetSelector::Restricted => UniverseType::NetDir,
#[cfg(feature = "bridge-client")]
GuardSetSelector::Bridges => UniverseType::BridgeSet,
}
}
}
/// Persistent state for a guard manager, as serialized to disk.
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
struct GuardSets {
/// Which set of guards is currently in use?
#[serde(skip)]
active_set: GuardSetSelector,
/// The default set of guards to use.
///
/// We use this one when there is no filter, or the filter permits most of the
/// guards on the network.
default: GuardSet,
/// A guard set to use when we have a restrictive filter.
#[serde(default)]
restricted: GuardSet,
/// A guard set sampled from our configured bridges.
#[serde(default)]
#[cfg(feature = "bridge-client")]
bridges: GuardSet,
/// Unrecognized fields, including (possibly) other guard sets.
#[serde(flatten)]
remaining: HashMap<String, tor_persist::JsonValue>,
}
/// The key (filename) we use for storing our persistent guard state in the
/// `StateMgr`.
///
/// We used to store this in a different format in a filename called
/// "default_guards" (before Arti 0.1.0).
const STORAGE_KEY: &str = "guards";
/// A description of which circuits to retire because of a configuration change.
///
/// TODO(nickm): Eventually we will want to add a "Some" here, to support
/// removing only those circuits that correspond to no-longer-usable guards.
#[derive(Clone, Debug, Eq, PartialEq)]
#[must_use]
#[non_exhaustive]
pub enum RetireCircuits {
/// There's no need to retire any circuits.
None,
/// All circuits should be retired.
All,
}
impl<R: Runtime> GuardMgr<R> {
/// Create a new "empty" guard manager and launch its background tasks.
///
/// It won't be able to hand out any guards until a [`NetDirProvider`] has
/// been installed.
pub fn new<S>(
runtime: R,
state_mgr: S,
config: &impl GuardMgrConfig,
) -> Result<Self, GuardMgrError>
where
S: StateMgr + Send + Sync + 'static,
{
let (ctrl, rcv) = mpsc::unbounded();
let storage: DynStorageHandle<GuardSets> = state_mgr.create_handle(STORAGE_KEY);
// TODO(nickm): We should do something about the old state in
// `default_guards`. Probably it would be best to delete it. We could
// try to migrate it instead, but that's beyond the stability guarantee
// that we're getting at this stage of our (pre-0.1) development.
let state = storage.load()?.unwrap_or_default();
let (send_skew, recv_skew) = postage::watch::channel();
let recv_skew = ClockSkewEvents { inner: recv_skew };
let inner = Arc::new(Mutex::new(GuardMgrInner {
guards: state,
filter: GuardFilter::unfiltered(),
last_primary_retry_time: runtime.now(),
params: GuardParams::default(),
ctrl,
pending: HashMap::new(),
waiting: Vec::new(),
fallbacks: config.fallbacks().into(),
storage,
send_skew,
recv_skew,
netdir_provider: None,
#[cfg(feature = "bridge-client")]
bridge_desc_provider: None,
#[cfg(feature = "bridge-client")]
configured_bridges: None,
}));
#[cfg(feature = "bridge-client")]
{
let mut inner = inner.lock().expect("lock poisoned");
// TODO(nickm): This calls `GuardMgrInner::update`. Will we mind doing so before any
// providers are configured? I think not, but we should make sure.
let _: RetireCircuits =
inner.replace_bridge_config(config, runtime.wallclock(), runtime.now())?;
}
{
let weak_inner = Arc::downgrade(&inner);
let rt_clone = runtime.clone();
runtime
.spawn(daemon::report_status_events(rt_clone, weak_inner, rcv))
.map_err(|e| GuardMgrError::from_spawn("guard status event reporter", e))?;
}
{
let rt_clone = runtime.clone();
let weak_inner = Arc::downgrade(&inner);
runtime
.spawn(daemon::run_periodic(rt_clone, weak_inner))
.map_err(|e| GuardMgrError::from_spawn("periodic guard updater", e))?;
}
Ok(GuardMgr { runtime, inner })
}
/// Install a [`NetDirProvider`] for use by this guard manager.
///
/// It will be used to keep the guards up-to-date with changes from the
/// network directory, and to find new guards when no NetDir is provided to
/// select_guard().
///
/// TODO: we should eventually return some kind of a task handle from this
/// task, even though it is not strictly speaking periodic.
///
/// The guardmgr retains only a `Weak` reference to `provider`,
/// `install_netdir_provider` downgrades it on entry,
// TODO add ref to document when https://gitlab.torproject.org/tpo/core/arti/-/issues/624
// is fixed. Also, maybe take an owned `Weak` to start with.
//
/// # Panics
///
/// Panics if a [`NetDirProvider`] is already installed.
pub fn install_netdir_provider(
&self,
provider: &Arc<dyn NetDirProvider>,
) -> Result<(), GuardMgrError> {
let weak_provider = Arc::downgrade(provider);
{
let mut inner = self.inner.lock().expect("Poisoned lock");
assert!(inner.netdir_provider.is_none());
inner.netdir_provider = Some(weak_provider.clone());
}
let weak_inner = Arc::downgrade(&self.inner);
let rt_clone = self.runtime.clone();
self.runtime
.spawn(daemon::keep_netdir_updated(
rt_clone,
weak_inner,
weak_provider,
))
.map_err(|e| GuardMgrError::from_spawn("periodic guard netdir updater", e))?;
Ok(())
}
/// Configure a new [`bridge::BridgeDescProvider`] for this [`GuardMgr`].
///
/// It will be used to learn about changes in the set of available bridge
/// descriptors; we'll inform it whenever our desired set of bridge
/// descriptors changes.
///
/// TODO: Same todo as in `install_netdir_provider` about task handles.
///
/// # Panics
///
/// Panics if a [`bridge::BridgeDescProvider`] is already installed.
#[cfg(feature = "bridge-client")]
pub fn install_bridge_desc_provider(
&self,
provider: &Arc<dyn bridge::BridgeDescProvider>,
) -> Result<(), GuardMgrError> {
let weak_provider = Arc::downgrade(provider);
{
let mut inner = self.inner.lock().expect("Poisoned lock");
assert!(inner.bridge_desc_provider.is_none());
inner.bridge_desc_provider = Some(weak_provider.clone());
}
let weak_inner = Arc::downgrade(&self.inner);
let rt_clone = self.runtime.clone();
self.runtime
.spawn(daemon::keep_bridge_descs_updated(
rt_clone,
weak_inner,
weak_provider,
))
.map_err(|e| GuardMgrError::from_spawn("periodic guard netdir updater", e))?;
Ok(())
}
/// Flush our current guard state to the state manager, if there
/// is any unsaved state.
pub fn store_persistent_state(&self) -> Result<(), GuardMgrError> {
let inner = self.inner.lock().expect("Poisoned lock");
trace!("Flushing guard state to disk.");
inner.storage.store(&inner.guards)?;
Ok(())
}
/// Reload state from the state manager.
///
/// We only call this method if we _don't_ have the lock on the state
/// files. If we have the lock, we only want to save.
pub fn reload_persistent_state(&self) -> Result<(), GuardMgrError> {
let mut inner = self.inner.lock().expect("Poisoned lock");
if let Some(new_guards) = inner.storage.load()? {
inner.replace_guards_with(new_guards, self.runtime.wallclock(), self.runtime.now());
}
Ok(())
}
/// Switch from having an unowned persistent state to having an owned one.
///
/// Requires that we hold the lock on the state files.
pub fn upgrade_to_owned_persistent_state(&self) -> Result<(), GuardMgrError> {
let mut inner = self.inner.lock().expect("Poisoned lock");
debug_assert!(inner.storage.can_store());
let new_guards = inner.storage.load()?.unwrap_or_default();
let wallclock = self.runtime.wallclock();
let now = self.runtime.now();
inner.replace_guards_with(new_guards, wallclock, now);
Ok(())
}
/// Return true if `netdir` has enough information to safely become our new netdir.
pub fn netdir_is_sufficient(&self, netdir: &NetDir) -> bool {
let mut inner = self.inner.lock().expect("Poisoned lock");
if inner.guards.active_set.universe_type() != UniverseType::NetDir {
// If we aren't using the netdir, this isn't something we want to look at.
return true;
}
inner
.guards
.active_guards_mut()
.n_primary_without_id_info_in(netdir)
== 0
}
/// Mark every guard as potentially retriable, regardless of how recently we
/// failed to connect to it.
pub fn mark_all_guards_retriable(&self) {
let mut inner = self.inner.lock().expect("Poisoned lock");
inner.guards.active_guards_mut().mark_all_guards_retriable();
}
/// Configure this guardmgr to use a fixed [`NetDir`] instead of a provider.
///
/// This function is for testing only, and is exclusive with
/// `install_netdir_provider`.
///
/// # Panics
///
/// Panics if any [`NetDirProvider`] has already been installed.
#[cfg(any(test, feature = "testing"))]
pub fn install_test_netdir(&self, netdir: &NetDir) {
use tor_netdir::testprovider::TestNetDirProvider;
let wallclock = self.runtime.wallclock();
let now = self.runtime.now();
let netdir_provider: Arc<dyn NetDirProvider> =
Arc::new(TestNetDirProvider::from(netdir.clone()));
self.install_netdir_provider(&netdir_provider)
.expect("Couldn't install testing network provider");
let mut inner = self.inner.lock().expect("Poisoned lock");
inner.update(wallclock, now);
}
/// Replace the configuration in this `GuardMgr` with `config`.
pub fn reconfigure(
&self,
config: &impl GuardMgrConfig,
) -> Result<RetireCircuits, ReconfigureError> {
let mut inner = self.inner.lock().expect("Poisoned lock");
// Change the set of configured fallbacks.
{
let mut fallbacks: fallback::FallbackState = config.fallbacks().into();
std::mem::swap(&mut inner.fallbacks, &mut fallbacks);
inner.fallbacks.take_status_from(fallbacks);
}
// If we are built to use bridges, change the bridge configuration.
#[cfg(feature = "bridge-client")]
{
let wallclock = self.runtime.wallclock();
let now = self.runtime.now();
Ok(inner.replace_bridge_config(config, wallclock, now)?)
}
// If we are built to use bridges, change the bridge configuration.
#[cfg(not(feature = "bridge-client"))]
{
Ok(RetireCircuits::None)
}
}
/// Replace the current [`GuardFilter`] used by this `GuardMgr`.
// TODO should this be part of the config?
pub fn set_filter(&self, filter: GuardFilter) {
let wallclock = self.runtime.wallclock();
let now = self.runtime.now();
let mut inner = self.inner.lock().expect("Poisoned lock");
inner.set_filter(filter, wallclock, now);
}
/// Select a guard for a given [`GuardUsage`].
///
/// On success, we return a [`FirstHop`] object to identify which
/// guard we have picked, a [`GuardMonitor`] object that the
/// caller can use to report whether its attempt to use the guard
/// succeeded or failed, and a [`GuardUsable`] future that the
/// caller can use to decide whether a circuit built through the
/// guard is actually safe to use.
///
/// That last point is important: It's okay to build a circuit
/// through the guard returned by this function, but you can't
/// actually use it for traffic unless the [`GuardUsable`] future
/// yields "true".
pub fn select_guard(
&self,
usage: GuardUsage,
) -> Result<(FirstHop, GuardMonitor, GuardUsable), PickGuardError> {
let now = self.runtime.now();
let wallclock = self.runtime.wallclock();
let mut inner = self.inner.lock().expect("Poisoned lock");
// (I am not 100% sure that we need to consider_all_retries here, but
// it should _probably_ not hurt.)
inner.guards.active_guards_mut().consider_all_retries(now);
let (origin, guard) = inner.select_guard_with_expand(&usage, now, wallclock)?;
trace!(?guard, ?usage, "Guard selected");
let (usable, usable_sender) = if origin.usable_immediately() {
(GuardUsable::new_usable_immediately(), None)
} else {
let (u, snd) = GuardUsable::new_uncertain();
(u, Some(snd))
};
let request_id = pending::RequestId::next();
let ctrl = inner.ctrl.clone();
let monitor = GuardMonitor::new(request_id, ctrl);
// Note that the network can be down even if all the primary guards
// are not yet marked as unreachable. But according to guard-spec we
// don't want to acknowledge the net as down before that point, since
// we don't mark all the primary guards as retriable unless
// we've been forced to non-primary guards.
let net_has_been_down =
if let Some(duration) = tor_proto::time_since_last_incoming_traffic() {
inner
.guards
.active_guards_mut()
.all_primary_guards_are_unreachable()
&& duration >= inner.params.internet_down_timeout
} else {
// TODO: Is this the correct behavior in this case?
false
};
let pending_request = pending::PendingRequest::new(
guard.first_hop_id(),
usage,
usable_sender,
net_has_been_down,
);
inner.pending.insert(request_id, pending_request);
match &guard.sample {
Some(sample) => {
let guard_id = GuardId::from_relay_ids(&guard);
inner
.guards
.guards_mut(sample)
.record_attempt(&guard_id, now);
}
None => {
// We don't record attempts for fallbacks; we only care when
// they have failed.
}
}
Ok((guard, monitor, usable))
}
/// Record that _after_ we built a circuit with a guard, something described
/// in `external_failure` went wrong with it.
pub fn note_external_failure<T>(&self, identity: &T, external_failure: ExternalActivity)
where
T: tor_linkspec::HasRelayIds + ?Sized,
{
let now = self.runtime.now();
let mut inner = self.inner.lock().expect("Poisoned lock");
let ids = inner.lookup_ids(identity);
for id in ids {
match &id.0 {
FirstHopIdInner::Guard(sample, id) => {
inner
.guards
.guards_mut(sample)
.record_failure(id, Some(external_failure), now);
}
FirstHopIdInner::Fallback(id) => {
if external_failure == ExternalActivity::DirCache {
inner.fallbacks.note_failure(id, now);
}
}
}
}
}
/// Record that _after_ we built a circuit with a guard, some activity
/// described in `external_activity` was successful with it.
pub fn note_external_success<T>(&self, identity: &T, external_activity: ExternalActivity)
where
T: tor_linkspec::HasRelayIds + ?Sized,
{
let mut inner = self.inner.lock().expect("Poisoned lock");
inner.record_external_success(identity, external_activity, self.runtime.wallclock());
}
/// Return a stream of events about our estimated clock skew; these events
/// are `None` when we don't have enough information to make an estimate,
/// and `Some(`[`SkewEstimate`]`)` otherwise.
///
/// Note that this stream can be lossy: if the estimate changes more than
/// one before you read from the stream, you might only get the most recent
/// update.
pub fn skew_events(&self) -> ClockSkewEvents {
let inner = self.inner.lock().expect("Poisoned lock");
inner.recv_skew.clone()
}
/// Ensure that the message queue is flushed before proceeding to
/// the next step. Used for testing.
#[cfg(test)]
async fn flush_msg_queue(&self) {
let (snd, rcv) = oneshot::channel();
let pingmsg = daemon::Msg::Ping(snd);
{
let inner = self.inner.lock().expect("Poisoned lock");
inner
.ctrl
.unbounded_send(pingmsg)
.expect("Guard observer task exited prematurely.");
}
let _ = rcv.await;
}
}
/// An activity that can succeed or fail, and whose success or failure can be
/// attributed to a guard.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
#[non_exhaustive]
pub enum ExternalActivity {
/// The activity of using the guard as a directory cache.
DirCache,
}
impl GuardSets {
/// Return a reference to the currently active set of guards.
///
/// (That's easy enough for now, since there is never more than one set of
/// guards. But eventually that will change, as we add support for more
/// complex filter types, and for bridge relays. Those will use separate
/// `GuardSet` instances, and this accessor will choose the right one.)
fn active_guards(&self) -> &GuardSet {
self.guards(&self.active_set)
}
/// Return the set of guards corresponding to the provided selector.
fn guards(&self, selector: &GuardSetSelector) -> &GuardSet {
match selector {
GuardSetSelector::Default => &self.default,
GuardSetSelector::Restricted => &self.restricted,
#[cfg(feature = "bridge-client")]
GuardSetSelector::Bridges => &self.bridges,
}
}
/// Return a mutable reference to the currently active set of guards.
fn active_guards_mut(&mut self) -> &mut GuardSet {
self.guards_mut(&self.active_set.clone())
}
/// Return a mutable reference to the set of guards corresponding to the
/// provided selector.
fn guards_mut(&mut self, selector: &GuardSetSelector) -> &mut GuardSet {
match selector {
GuardSetSelector::Default => &mut self.default,
GuardSetSelector::Restricted => &mut self.restricted,
#[cfg(feature = "bridge-client")]
GuardSetSelector::Bridges => &mut self.bridges,
}
}
/// Update all non-persistent state for the guards in this object with the
/// state in `other`.
fn copy_status_from(&mut self, mut other: GuardSets) {
use strum::IntoEnumIterator;
for sample in GuardSetSelector::iter() {
self.guards_mut(&sample)
.copy_ephemeral_status_into_newly_loaded_state(std::mem::take(
other.guards_mut(&sample),
));
}
self.active_set = other.active_set;
}
}
impl GuardMgrInner {
/// Look up the latest [`NetDir`] (if there is one) from our
/// [`NetDirProvider`] (if we have one).
fn timely_netdir(&self) -> Option<Arc<NetDir>> {
self.netdir_provider
.as_ref()
.and_then(Weak::upgrade)
.and_then(|np| np.timely_netdir().ok())
}
/// Look up the latest [`BridgeDescList`](bridge::BridgeDescList) (if there
/// is one) from our [`BridgeDescProvider`](bridge::BridgeDescProvider) (if
/// we have one).
#[cfg(feature = "bridge-client")]
fn latest_bridge_desc_list(&self) -> Option<Arc<bridge::BridgeDescList>> {
self.bridge_desc_provider
.as_ref()
.and_then(Weak::upgrade)
.map(|bp| bp.bridges())
}
/// Run a function that takes `&mut self` and an optional NetDir.
///
/// We try to use the netdir from our [`NetDirProvider`] (if we have one).
/// Therefore, although its _parameters_ are suitable for every
/// [`GuardSet`], its _contents_ might not be. For those, call
/// [`with_opt_universe`](Self::with_opt_universe) instead.
//
// This function exists to handle the lifetime mess where sometimes the
// resulting NetDir will borrow from `netdir`, and sometimes it will borrow
// from an Arc returned by `self.latest_netdir()`.
fn with_opt_netdir<F, T>(&mut self, func: F) -> T
where
F: FnOnce(&mut Self, Option<&NetDir>) -> T,
{
if let Some(nd) = self.timely_netdir() {
func(self, Some(nd.as_ref()))
} else {
func(self, None)
}
}
/// Return the latest `BridgeSet` based on our `BridgeDescProvider` and our
/// configured bridges.
///
/// Returns `None` if we are not configured to use bridges.
#[cfg(feature = "bridge-client")]
fn latest_bridge_set(&self) -> Option<bridge::BridgeSet> {
let bridge_config = self.configured_bridges.as_ref()?.clone();
let bridge_descs = self.latest_bridge_desc_list();
Some(bridge::BridgeSet::new(bridge_config, bridge_descs))
}
/// Run a function that takes `&mut self` and an optional [`UniverseRef`].
///
/// We try to get a universe from the appropriate source for the current
/// active guard set.
fn with_opt_universe<F, T>(&mut self, func: F) -> T
where
F: FnOnce(&mut Self, Option<&UniverseRef>) -> T,
{
// TODO: it might be nice to make `func` take an GuardSet and a set of
// parameters, so we can't get the active set wrong. Doing that will
// require a fair amount of refactoring so that the borrow checker is
// happy, however.
match self.guards.active_set.universe_type() {
UniverseType::NetDir => {
if let Some(nd) = self.timely_netdir() {
func(self, Some(&UniverseRef::NetDir(nd)))
} else {
func(self, None)
}
}
#[cfg(feature = "bridge-client")]
UniverseType::BridgeSet => func(
self,
self.latest_bridge_set()
.map(UniverseRef::BridgeSet)
.as_ref(),
),
}
}
/// Update the status of all guards in the active set, based on the passage
/// of time, our configuration, and the relevant Universe for our active
/// set.
fn update(&mut self, wallclock: SystemTime, now: Instant) {
self.with_opt_netdir(|this, netdir| {
// Here we update our parameters from the latest NetDir, and check
// whether we need to change to a (non)-restrictive GuardSet based
// on those parameters and our configured filter.
//
// This uses a NetDir unconditionally, since we always want to take
// the network parameters our parameters from the consensus even if
// the guards themselves are from a BridgeSet.
this.update_active_set_params_and_filter(netdir);
});
self.with_opt_universe(|this, univ| {
// Now we update the set of guards themselves based on the
// Universe, which is either the latest NetDir, or the latest
// BridgeSet—depending on what the GuardSet wants.
Self::update_guardset_internal(
&this.params,
wallclock,
this.guards.active_set.universe_type(),
this.guards.active_guards_mut(),
univ,
);
#[cfg(feature = "bridge-client")]
this.update_desired_descriptors(now);
#[cfg(not(feature = "bridge-client"))]
let _ = now;
});
}
/// Replace our bridge configuration with the one from `new_config`.
#[cfg(feature = "bridge-client")]
fn replace_bridge_config(
&mut self,
new_config: &impl GuardMgrConfig,
wallclock: SystemTime,
now: Instant,
) -> Result<RetireCircuits, GuardMgrConfigError> {
match (&self.configured_bridges, new_config.bridges_enabled()) {
(None, false) => {
assert_ne!(
self.guards.active_set.universe_type(),
UniverseType::BridgeSet
);
return Ok(RetireCircuits::None); // nothing to do
}
(_, true) if !self.storage.can_store() => {
// TODO: Ideally we would try to upgrade, obtaining an exclusive lock,
// but `StorageHandle` currently lacks a method for that.
return Err(GuardMgrConfigError::NoLock("bridges configured".into()));
}
(Some(current_bridges), true) if new_config.bridges() == current_bridges.as_ref() => {
assert_eq!(
self.guards.active_set.universe_type(),
UniverseType::BridgeSet
);
return Ok(RetireCircuits::None); // nothing to do.
}
(_, true) => {
self.configured_bridges = Some(new_config.bridges().into());
self.guards.active_set = GuardSetSelector::Bridges;
}
(_, false) => {
self.configured_bridges = None;
self.guards.active_set = GuardSetSelector::Default;
}
}
// If we have gotten here, we have changed the set of bridges, changed
// which set is active, or changed them both. We need to make sure that
// our `GuardSet` object is up-to-date with our configuration.
self.update(wallclock, now);
// We also need to tell the caller that its circuits are no good any
// more.
//
// TODO(nickm): Someday we can do this more judiciously by retuning
// "Some" in the case where we're still using bridges but our new bridge
// set contains different elements; see comment on RetireCircuits.
//
// TODO(nickm): We could also safely return RetireCircuits::None if we
// are using bridges, and our new bridge list is a superset of the older
// one.
Ok(RetireCircuits::All)
}
/// Update our parameters, our selection (based on network parameters and
/// configuration), and make sure the active GuardSet has the right
/// configuration itself.
///
/// We should call this whenever the NetDir's parameters change, or whenever
/// our filter changes. We do not need to call it for new elements arriving
/// in our Universe, since those do not affect anything here.
///
/// We should also call this whenever a new GuardSet becomes active for any
/// reason _other_ than just having called this function.
///
/// (This function is only invoked from `update`, which should be called
/// under the above circumstances.)
fn update_active_set_params_and_filter(&mut self, netdir: Option<&NetDir>) {
// Set the parameters. These always come from the NetDir, even if this
// is a bridge set.
if let Some(netdir) = netdir {
match GuardParams::try_from(netdir.params()) {
Ok(params) => self.params = params,
Err(e) => warn!("Unusable guard parameters from consensus: {}", e),
}
self.select_guard_set_based_on_filter(netdir);
}
// Change the filter, if it doesn't match what the guards have.
//
// TODO(nickm): We could use a "dirty" flag or something to decide
// whether we need to call set_filter, if this comparison starts to show
// up in profiles.
if self.guards.active_guards().filter() != &self.filter {
let restrictive = self.guards.active_set == GuardSetSelector::Restricted;
self.guards
.active_guards_mut()
.set_filter(self.filter.clone(), restrictive);
}
}
/// Update the status of every guard in `active_guards`, and expand it as
/// needed.
///
/// This function doesn't take `&self`, to make sure that we are only
/// affecting a single `GuardSet`, and to avoid confusing the borrow
/// checker.
///
/// We should call this whenever the contents of the universe have changed.
///
/// We should also call this whenever a new GuardSet becomes active.
fn update_guardset_internal<U: Universe>(
params: &GuardParams,
now: SystemTime,
universe_type: UniverseType,
active_guards: &mut GuardSet,
universe: Option<&U>,
) -> ExtendedStatus {
// Expire guards. Do that early, in case doing so makes it clear that
// we need to grab more guards or mark others as primary.
active_guards.expire_old_guards(params, now);
let extended = if let Some(universe) = universe {
// TODO: This check here may be completely unnecessary. I inserted
// it back in 5ac0fcb7ef603e0d14 because I was originally concerned
// it might be undesirable to list a primary guard as "missing dir
// info" (and therefore unusable) if we were expecting to get its
// microdescriptor "very soon."
//
// But due to the other check in `netdir_is_sufficient`, we
// shouldn't be installing a netdir until it has microdescs for all
// of the (non-bridge) primary guards that it lists. - nickm
if active_guards.n_primary_without_id_info_in(universe) > 0
&& universe_type == UniverseType::NetDir
{
// We are missing the information from a NetDir needed to see
// whether our primary guards are listed, so we shouldn't update
// our guard status.
//
// We don't want to do this check if we are using bridges, since
// a missing bridge descriptor is not guaranteed to temporary
// problem in the same way that a missing microdescriptor is.
// (When a bridge desc is missing, the bridge could be down or
// unreachable, and nobody else can help us. But if a microdesc
// is missing, we just need to find a cache that has it.)
return ExtendedStatus::No;
}
active_guards.update_status_from_dir(universe);
active_guards.extend_sample_as_needed(now, params, universe)
} else {
ExtendedStatus::No
};
active_guards.select_primary_guards(params);
extended
}
/// If using bridges, tell the BridgeDescProvider which descriptors we want.
/// We need to check this *after* we select our primary guards.
#[cfg(feature = "bridge-client")]
fn update_desired_descriptors(&mut self, now: Instant) {
if self.guards.active_set.universe_type() != UniverseType::BridgeSet {
return;
}
let provider = self.bridge_desc_provider.as_ref().and_then(Weak::upgrade);
let bridge_set = self.latest_bridge_set();
if let (Some(provider), Some(bridge_set)) = (provider, bridge_set) {
let desired: Vec<_> = self
.guards
.active_guards()
.descriptors_to_request(now, &self.params)
.into_iter()
.flat_map(|guard| bridge_set.bridge_by_guard(guard))
.cloned()
.collect();
provider.set_bridges(&desired);
}
}
/// Replace the active guard state with `new_state`, preserving
/// non-persistent state for any guards that are retained.
fn replace_guards_with(
&mut self,
mut new_guards: GuardSets,
wallclock: SystemTime,
now: Instant,
) {
std::mem::swap(&mut self.guards, &mut new_guards);
self.guards.copy_status_from(new_guards);
self.update(wallclock, now);
}
/// Update which guard set is active based on the current filter and the
/// provided netdir.
///
/// After calling this function, the new guard set's filter may be
/// out-of-date: be sure to call `set_filter` as appropriate.
fn select_guard_set_based_on_filter(&mut self, netdir: &NetDir) {
// In general, we'd like to use the restricted set if we're under the
// threshold, and the default set if we're over the threshold. But if
// we're sitting close to the threshold, we want to avoid flapping back
// and forth, so we only change when we're more than 5% "off" from
// whatever our current setting is.
//
// (See guard-spec section 2 for more information.)
let offset = match self.guards.active_set {
GuardSetSelector::Default => -0.05,
GuardSetSelector::Restricted => 0.05,
// If we're using bridges, then we don't switch between the other guard sets based on on the filter at all.
#[cfg(feature = "bridge-client")]
GuardSetSelector::Bridges => return,
};
let frac_permitted = self.filter.frac_bw_permitted(netdir);
let threshold = self.params.filter_threshold + offset;
let new_choice = if frac_permitted < threshold {
GuardSetSelector::Restricted
} else {
GuardSetSelector::Default
};
if new_choice != self.guards.active_set {
info!(
"Guard selection changed; we are now using the {:?} guard set",
&new_choice
);
self.guards.active_set = new_choice;
if frac_permitted < self.params.extreme_threshold {
warn!(
"The number of guards permitted is smaller than the recommended minimum of {:.0}%.",
self.params.extreme_threshold * 100.0,
);
}
}
}
/// Mark all of our primary guards as retriable, if we haven't done
/// so since long enough before `now`.
///
/// We want to call this function whenever a guard attempt succeeds,
/// if the internet seemed to be down when the guard attempt was
/// first launched.
fn maybe_retry_primary_guards(&mut self, now: Instant) {
// We don't actually want to mark our primary guards as
// retriable more than once per internet_down_timeout: after
// the first time, we would just be noticing the same "coming
// back online" event more than once.
let interval = self.params.internet_down_timeout;
if self.last_primary_retry_time + interval <= now {
debug!("Successfully reached a guard after a while off the internet; marking all primary guards retriable.");
self.guards
.active_guards_mut()
.mark_primary_guards_retriable();
self.last_primary_retry_time = now;
}
}
/// Replace the current GuardFilter with `filter`.
fn set_filter(&mut self, filter: GuardFilter, wallclock: SystemTime, now: Instant) {
self.filter = filter;
self.update(wallclock, now);
}
/// Called when the circuit manager reports (via [`GuardMonitor`]) that
/// a guard succeeded or failed.
///
/// Changes the guard's status as appropriate, and updates the pending
/// request as needed.
#[allow(clippy::cognitive_complexity)]
pub(crate) fn handle_msg(
&mut self,
request_id: RequestId,
status: GuardStatus,
skew: Option<ClockSkew>,
runtime: &impl tor_rtcompat::SleepProvider,
) {
if let Some(mut pending) = self.pending.remove(&request_id) {
// If there was a pending request matching this RequestId, great!
let guard_id = pending.guard_id();
trace!(?guard_id, ?status, "Received report of guard status");
// First, handle the skew report (if any)
if let Some(skew) = skew {
let now = runtime.now();
let observation = skew::SkewObservation { skew, when: now };
match &guard_id.0 {
FirstHopIdInner::Guard(_, id) => {
self.guards.active_guards_mut().record_skew(id, observation);
}
FirstHopIdInner::Fallback(id) => {
self.fallbacks.note_skew(id, observation);
}
}
// TODO: We call this whenever we receive an observed clock
// skew. That's not the perfect timing for two reasons. First
// off, it might be too frequent: it does an O(n) calculation,
// which isn't ideal. Second, it might be too infrequent: after
// an hour has passed, a given observation won't be up-to-date
// any more, and we might want to recalculate the skew
// accordingly.
self.update_skew(now);
}
match (status, &guard_id.0) {
(GuardStatus::Failure, FirstHopIdInner::Fallback(id)) => {
// We used a fallback, and we weren't able to build a circuit through it.
self.fallbacks.note_failure(id, runtime.now());
}
(_, FirstHopIdInner::Fallback(_)) => {
// We don't record any other kind of circuit activity if we
// took the entry from the fallback list.
}
(GuardStatus::Success, FirstHopIdInner::Guard(sample, id)) => {
// If we had gone too long without any net activity when we
// gave out this guard, and now we're seeing a circuit
// succeed, tell the primary guards that they might be
// retriable.
if pending.net_has_been_down() {
self.maybe_retry_primary_guards(runtime.now());
}
// The guard succeeded. Tell the GuardSet.
self.guards.guards_mut(sample).record_success(
id,
&self.params,
None,
runtime.wallclock(),
);
// Either tell the request whether the guard is
// usable, or schedule it as a "waiting" request.
if let Some(usable) = self.guard_usability_status(&pending, runtime.now()) {
trace!(?guard_id, usable, "Known usability status");
pending.reply(usable);
} else {
// This is the one case where we can't use the
// guard yet.
trace!(?guard_id, "Not able to answer right now");
pending.mark_waiting(runtime.now());
self.waiting.push(pending);
}
}
(GuardStatus::Failure, FirstHopIdInner::Guard(sample, id)) => {
self.guards
.guards_mut(sample)
.record_failure(id, None, runtime.now());
pending.reply(false);
}
(GuardStatus::AttemptAbandoned, FirstHopIdInner::Guard(sample, id)) => {
self.guards.guards_mut(sample).record_attempt_abandoned(id);
pending.reply(false);
}
(GuardStatus::Indeterminate, FirstHopIdInner::Guard(sample, id)) => {
self.guards
.guards_mut(sample)
.record_indeterminate_result(id);
pending.reply(false);
}
};
} else {
warn!(
"Got a status {:?} for a request {:?} that wasn't pending",
status, request_id
);
}
// We might need to update the primary guards based on changes in the
// status of guards above.
self.guards
.active_guards_mut()
.select_primary_guards(&self.params);
// Some waiting request may just have become ready (usable or
// not); we need to give them the information they're waiting
// for.
self.expire_and_answer_pending_requests(runtime.now());
}
/// Helper to implement `GuardMgr::note_external_success()`.
///
/// (This has to be a separate function so that we can borrow params while
/// we have `mut self` borrowed.)
fn record_external_success<T>(
&mut self,
identity: &T,
external_activity: ExternalActivity,
now: SystemTime,
) where
T: tor_linkspec::HasRelayIds + ?Sized,
{
for id in self.lookup_ids(identity) {
match &id.0 {
FirstHopIdInner::Guard(sample, id) => {
self.guards.guards_mut(sample).record_success(
id,
&self.params,
Some(external_activity),
now,
);
}
FirstHopIdInner::Fallback(id) => {
if external_activity == ExternalActivity::DirCache {
self.fallbacks.note_success(id);
}
}
}
}
}
/// Return an iterator over all of the clock skew observations we've made
/// for guards or fallbacks.
fn skew_observations(&self) -> impl Iterator<Item = &skew::SkewObservation> {
self.fallbacks
.skew_observations()
.chain(self.guards.active_guards().skew_observations())
}
/// Recalculate our estimated clock skew, and publish it to anybody who
/// cares.
fn update_skew(&mut self, now: Instant) {
let estimate = skew::SkewEstimate::estimate_skew(self.skew_observations(), now);
// TODO: we might want to do this only conditionally, when the skew
// estimate changes.
*self.send_skew.borrow_mut() = estimate;
}
/// If the circuit built because of a given [`PendingRequest`] may
/// now be used (or discarded), return `Some(true)` or
/// `Some(false)` respectively.
///
/// Return None if we can't yet give an answer about whether such
/// a circuit is usable.
fn guard_usability_status(&self, pending: &PendingRequest, now: Instant) -> Option<bool> {
match &pending.guard_id().0 {
FirstHopIdInner::Guard(sample, id) => self.guards.guards(sample).circ_usability_status(
id,
pending.usage(),
&self.params,
now,
),
// Fallback circuits are usable immediately, since we don't have to wait to
// see whether any _other_ circuit succeeds or fails.
FirstHopIdInner::Fallback(_) => Some(true),
}
}
/// For requests that have been "waiting" for an answer for too long,
/// expire them and tell the circuit manager that their circuits
/// are unusable.
fn expire_and_answer_pending_requests(&mut self, now: Instant) {
// A bit ugly: we use a separate Vec here to avoid borrowing issues,
// and put it back when we're done.
let mut waiting = Vec::new();
std::mem::swap(&mut waiting, &mut self.waiting);
waiting.retain_mut(|pending| {
let expired = pending
.waiting_since()
.and_then(|w| now.checked_duration_since(w))
.map(|d| d >= self.params.np_idle_timeout)
== Some(true);
if expired {
trace!(?pending, "Pending request expired");
pending.reply(false);
return false;
}
// TODO-SPEC: guard_usability_status isn't what the spec says. It
// says instead that we should look at _circuit_ status, saying:
// " Definition: In the algorithm above, C2 "blocks" C1 if:
// * C2 obeys all the restrictions that C1 had to obey, AND
// * C2 has higher priority than C1, AND
// * Either C2 is <complete>, or C2 is <waiting_for_better_guard>,
// or C2 has been <usable_if_no_better_guard> for no more than
// {NONPRIMARY_GUARD_CONNECT_TIMEOUT} seconds."
//
// See comments in sample::GuardSet::circ_usability_status.
if let Some(answer) = self.guard_usability_status(pending, now) {
trace!(?pending, answer, "Pending request now ready");
pending.reply(answer);
return false;
}
true
});
// Put the waiting list back.
std::mem::swap(&mut waiting, &mut self.waiting);
}
/// Return every currently extant FirstHopId for a guard or fallback
/// directory matching (or possibly matching) the provided keys.
///
/// An identity is _possibly matching_ if it contains some of the IDs in the
/// provided identity, and it has no _contradictory_ identities, but it does
/// not necessarily contain _all_ of those identities.
///
/// # TODO
///
/// This function should probably not exist; it's only used so that dirmgr
/// can report successes or failures, since by the time it observes them it
/// doesn't know whether its circuit came from a guard or a fallback. To
/// solve that, we'll need CircMgr to record and report which one it was
/// using, which will take some more plumbing.
///
/// TODO relay: we will have to make the change above when we implement
/// relays; otherwise, it would be possible for an attacker to exploit it to
/// mislead us about our guard status.
fn lookup_ids<T>(&self, identity: &T) -> Vec<FirstHopId>
where
T: tor_linkspec::HasRelayIds + ?Sized,
{
use strum::IntoEnumIterator;
let mut vec = Vec::with_capacity(2);
let id = ids::GuardId::from_relay_ids(identity);
for sample in GuardSetSelector::iter() {
let guard_id = match self.guards.guards(&sample).contains(&id) {
Ok(true) => &id,
Err(other) => other,
Ok(false) => continue,
};
vec.push(FirstHopId(FirstHopIdInner::Guard(sample, guard_id.clone())));
}
let id = ids::FallbackId::from_relay_ids(identity);
if self.fallbacks.contains(&id) {
vec.push(id.into());
}
vec
}
/// Run any periodic events that update guard status, and return a
/// duration after which periodic events should next be run.
pub(crate) fn run_periodic_events(&mut self, wallclock: SystemTime, now: Instant) -> Duration {
self.update(wallclock, now);
self.expire_and_answer_pending_requests(now);
Duration::from_secs(1) // TODO: Too aggressive.
}
/// Try to select a guard, expanding the sample if the first attempt fails.
fn select_guard_with_expand(
&mut self,
usage: &GuardUsage,
now: Instant,
wallclock: SystemTime,
) -> Result<(sample::ListKind, FirstHop), PickGuardError> {
// Try to find a guard.
let first_error = match self.select_guard_once(usage, now) {
Ok(res1) => return Ok(res1),
Err(e) => {
trace!("Couldn't select guard on first attempt: {}", e);
e
}
};
// That didn't work. If we have a netdir, expand the sample and try again.
let res = self.with_opt_universe(|this, univ| {
let univ = univ?;
trace!("No guards available, trying to extend the sample.");
// Make sure that the status on all of our guards are accurate, and
// expand the sample if we can.
//
// Our parameters and configuration did not change, so we do not
// need to call update() or update_active_set_and_filter(). This
// call is sufficient to extend the sample and recompute primary
// guards.
let extended = Self::update_guardset_internal(
&this.params,
wallclock,
this.guards.active_set.universe_type(),
this.guards.active_guards_mut(),
Some(univ),
);
if extended == ExtendedStatus::Yes {
match this.select_guard_once(usage, now) {
Ok(res) => return Some(res),
Err(e) => {
trace!("Couldn't select guard after update: {}", e);
}
}
}
None
});
if let Some(res) = res {
return Ok(res);
}
// Okay, that didn't work either. If we were asked for a directory
// guard, and we aren't using bridges, then we may be able to use a
// fallback.
if usage.kind == GuardUsageKind::OneHopDirectory
&& self.guards.active_set.universe_type() == UniverseType::NetDir
{
return self.select_fallback(now);
}
// Couldn't extend the sample or use a fallback; return the original error.
Err(first_error)
}
/// Helper: try to pick a single guard, without retrying on failure.
fn select_guard_once(
&self,
usage: &GuardUsage,
now: Instant,
) -> Result<(sample::ListKind, FirstHop), PickGuardError> {
let active_set = &self.guards.active_set;
#[cfg_attr(not(feature = "bridge-client"), allow(unused_mut))]
let (list_kind, mut first_hop) =
self.guards
.guards(active_set)
.pick_guard(active_set, usage, &self.params, now)?;
#[cfg(feature = "bridge-client")]
if self.guards.active_set.universe_type() == UniverseType::BridgeSet {
// See if we can promote first_hop to a viable CircTarget.
let bridges = self.latest_bridge_set().ok_or_else(|| {
PickGuardError::Internal(internal!(
"No bridge set available, even though this is the Bridges sample"
))
})?;
first_hop.lookup_bridge_circ_target(&bridges);
if usage.kind == GuardUsageKind::Data && !first_hop.contains_circ_target() {
return Err(PickGuardError::Internal(internal!(
"Tried to return a non-circtarget guard with Data usage!"
)));
}
}
Ok((list_kind, first_hop))
}
/// Helper: Select a fallback directory.
///
/// Called when we have no guard information to use. Return values are as
/// for [`GuardMgr::select_guard()`]
fn select_fallback(
&self,
now: Instant,
) -> Result<(sample::ListKind, FirstHop), PickGuardError> {
let filt = self.guards.active_guards().filter();
let fallback = self
.fallbacks
.choose(&mut rand::thread_rng(), now, filt)?
.as_guard();
let fallback = filt.modify_hop(fallback)?;
Ok((sample::ListKind::Fallback, fallback))
}
}
/// A possible outcome of trying to extend a guard sample.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
enum ExtendedStatus {
/// The guard sample was extended. (At least one guard was added to it.)
Yes,
/// The guard sample was not extended.
No,
}
/// A set of parameters, derived from the consensus document, controlling
/// the behavior of a guard manager.
#[derive(Debug, Clone)]
#[cfg_attr(test, derive(PartialEq))]
struct GuardParams {
/// How long should a sampled, un-confirmed guard be kept in the sample before it expires?
lifetime_unconfirmed: Duration,
/// How long should a confirmed guard be kept in the sample before
/// it expires?
lifetime_confirmed: Duration,
/// How long may a guard be unlisted before we remove it from the sample?
lifetime_unlisted: Duration,
/// Largest number of guards we're willing to add to the sample.
max_sample_size: usize,
/// Largest fraction of the network's guard bandwidth that we're
/// willing to add to the sample.
max_sample_bw_fraction: f64,
/// Smallest number of guards that we're willing to have in the
/// sample, after applying a [`GuardFilter`].
min_filtered_sample_size: usize,
/// How many guards are considered "Primary"?
n_primary: usize,
/// When making a regular circuit, how many primary guards should we
/// be willing to try?
data_parallelism: usize,
/// When making a one-hop directory circuit, how many primary
/// guards should we be willing to try?
dir_parallelism: usize,
/// For how long does a pending attempt to connect to a guard
/// block an attempt to use a less-favored non-primary guard?
np_connect_timeout: Duration,
/// How long do we allow a circuit to a successful but unfavored
/// non-primary guard to sit around before deciding not to use it?
np_idle_timeout: Duration,
/// After how much time without successful activity does a
/// successful circuit indicate that we should retry our primary
/// guards?
internet_down_timeout: Duration,
/// What fraction of the guards can be can be filtered out before we
/// decide that our filter is "very restrictive"?
filter_threshold: f64,
/// What fraction of the guards determine that our filter is "very
/// restrictive"?
extreme_threshold: f64,
}
impl Default for GuardParams {
fn default() -> Self {
let one_day = Duration::from_secs(86400);
GuardParams {
lifetime_unconfirmed: one_day * 120,
lifetime_confirmed: one_day * 60,
lifetime_unlisted: one_day * 20,
max_sample_size: 60,
max_sample_bw_fraction: 0.2,
min_filtered_sample_size: 20,
n_primary: 3,
data_parallelism: 1,
dir_parallelism: 3,
np_connect_timeout: Duration::from_secs(15),
np_idle_timeout: Duration::from_secs(600),
internet_down_timeout: Duration::from_secs(600),
filter_threshold: 0.2,
extreme_threshold: 0.01,
}
}
}
impl TryFrom<&NetParameters> for GuardParams {
type Error = tor_units::Error;
fn try_from(p: &NetParameters) -> Result<GuardParams, Self::Error> {
Ok(GuardParams {
lifetime_unconfirmed: p.guard_lifetime_unconfirmed.try_into()?,
lifetime_confirmed: p.guard_lifetime_confirmed.try_into()?,
lifetime_unlisted: p.guard_remove_unlisted_after.try_into()?,
max_sample_size: p.guard_max_sample_size.try_into()?,
max_sample_bw_fraction: p.guard_max_sample_threshold.as_fraction(),
min_filtered_sample_size: p.guard_filtered_min_sample_size.try_into()?,
n_primary: p.guard_n_primary.try_into()?,
data_parallelism: p.guard_use_parallelism.try_into()?,
dir_parallelism: p.guard_dir_use_parallelism.try_into()?,
np_connect_timeout: p.guard_nonprimary_connect_timeout.try_into()?,
np_idle_timeout: p.guard_nonprimary_idle_timeout.try_into()?,
internet_down_timeout: p.guard_internet_likely_down.try_into()?,
filter_threshold: p.guard_meaningful_restriction.as_fraction(),
extreme_threshold: p.guard_extreme_restriction.as_fraction(),
})
}
}
/// Representation of a guard or fallback, as returned by [`GuardMgr::select_guard()`].
#[derive(Debug, Clone)]
pub struct FirstHop {
/// The sample from which this guard was taken, or `None` if this is a fallback.
sample: Option<GuardSetSelector>,
/// Information about connecting to (or through) this guard.
inner: FirstHopInner,
}
/// The enumeration inside a FirstHop that holds information about how to
/// connect to (and possibly through) a guard or fallback.
#[derive(Debug, Clone)]
enum FirstHopInner {
/// We have enough information to connect to a guard.
Chan(OwnedChanTarget),
/// We have enough information to connect to a guards _and_ to build
/// multihop circuits through it.
#[cfg_attr(not(feature = "bridge-client"), allow(dead_code))]
Circ(OwnedCircTarget),
}
impl FirstHop {
/// Return a new [`FirstHopId`] for this `FirstHop`.
fn first_hop_id(&self) -> FirstHopId {
match &self.sample {
Some(sample) => {
let guard_id = GuardId::from_relay_ids(self);
FirstHopId::in_sample(sample.clone(), guard_id)
}
None => {
let fallback_id = crate::ids::FallbackId::from_relay_ids(self);
FirstHopId::from(fallback_id)
}
}
}
/// Look up this guard in `netdir`.
pub fn get_relay<'a>(&self, netdir: &'a NetDir) -> Option<Relay<'a>> {
match &self.sample {
#[cfg(feature = "bridge-client")]
// Always return "None" for anything that isn't in the netdir.
Some(s) if s.universe_type() == UniverseType::BridgeSet => None,
// Otherwise ask the netdir.
_ => netdir.by_ids(self),
}
}
/// If possible, return a view of this object that can be used to build a circuit.
pub fn as_circ_target(&self) -> Option<&OwnedCircTarget> {
match &self.inner {
FirstHopInner::Chan(_) => None,
FirstHopInner::Circ(ct) => Some(ct),
}
}
/// Return a view of this as an OwnedChanTarget.
fn chan_target_mut(&mut self) -> &mut OwnedChanTarget {
match &mut self.inner {
FirstHopInner::Chan(ct) => ct,
FirstHopInner::Circ(ct) => ct.chan_target_mut(),
}
}
/// If possible and appropriate, find a circuit target in `bridges` for this
/// `FirstHop`, and make this `FirstHop` a viable circuit target.
///
/// (By default, any `FirstHop` that a `GuardSet` returns will have enough
/// information to be a `ChanTarget`, but it will be lacking the additional
/// network information in `CircTarget`[^1] necessary for us to build a
/// multi-hop circuit through it. If this FirstHop is a regular non-bridge
/// `Relay`, then the `CircMgr` will later look up that circuit information
/// itself from the network directory. But if this `FirstHop` *is* a bridge,
/// then we need to find that information in the `BridgeSet`, since the
/// CircMgr does not keep track of the `BridgeSet`.)
///
/// [^1]: For example, supported protocol versions and ntor keys.
#[cfg(feature = "bridge-client")]
fn lookup_bridge_circ_target(&mut self, bridges: &bridge::BridgeSet) {
use crate::sample::CandidateStatus::Present;
if self.sample.as_ref().map(|s| s.universe_type()) == Some(UniverseType::BridgeSet)
&& matches!(self.inner, FirstHopInner::Chan(_))
{
if let Present(bridge_relay) = bridges.bridge_relay_by_guard(self) {
if let Some(circ_target) = bridge_relay.as_relay_with_desc() {
self.inner =
FirstHopInner::Circ(OwnedCircTarget::from_circ_target(&circ_target));
}
}
}
}
/// Return true if this `FirstHop` contains circuit target information.
///
/// This is true if `lookup_bridge_circ_target()` has been called, and it
/// successfully found the circuit target information.
#[cfg(feature = "bridge-client")]
fn contains_circ_target(&self) -> bool {
matches!(self.inner, FirstHopInner::Circ(_))
}
}
// This is somewhat redundant with the implementations in crate::guard::Guard.
impl tor_linkspec::HasAddrs for FirstHop {
fn addrs(&self) -> &[SocketAddr] {
match &self.inner {
FirstHopInner::Chan(ct) => ct.addrs(),
FirstHopInner::Circ(ct) => ct.addrs(),
}
}
}
impl tor_linkspec::HasRelayIds for FirstHop {
fn identity(
&self,
key_type: tor_linkspec::RelayIdType,
) -> Option<tor_linkspec::RelayIdRef<'_>> {
match &self.inner {
FirstHopInner::Chan(ct) => ct.identity(key_type),
FirstHopInner::Circ(ct) => ct.identity(key_type),
}
}
}
impl tor_linkspec::HasChanMethod for FirstHop {
fn chan_method(&self) -> tor_linkspec::ChannelMethod {
match &self.inner {
FirstHopInner::Chan(ct) => ct.chan_method(),
FirstHopInner::Circ(ct) => ct.chan_method(),
}
}
}
impl tor_linkspec::ChanTarget for FirstHop {}
/// The purpose for which we plan to use a guard.
///
/// This can affect the guard selection algorithm.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
#[non_exhaustive]
pub enum GuardUsageKind {
/// We want to use this guard for a data circuit.
///
/// (This encompasses everything except the `OneHopDirectory` case.)
#[default]
Data,
/// We want to use this guard for a one-hop, non-anonymous
/// directory request.
///
/// (Our algorithm allows more parallelism for the guards that we use
/// for these circuits.)
OneHopDirectory,
}
/// A set of parameters describing how a single guard should be selected.
///
/// Used as an argument to [`GuardMgr::select_guard`].
#[derive(Clone, Debug, derive_builder::Builder)]
#[builder(build_fn(error = "tor_config::ConfigBuildError"))]
pub struct GuardUsage {
/// The purpose for which this guard will be used.
#[builder(default)]
kind: GuardUsageKind,
/// A list of restrictions on which guard may be used.
///
/// The default is the empty list.
#[builder(sub_builder, setter(custom))]
restrictions: GuardRestrictionList,
}
impl_standard_builder! { GuardUsage: !Deserialize }
/// List of socket restrictions, as configured
pub type GuardRestrictionList = Vec<GuardRestriction>;
define_list_builder_helper! {
pub struct GuardRestrictionListBuilder {
restrictions: [GuardRestriction],
}
built: GuardRestrictionList = restrictions;
default = vec![];
item_build: |restriction| Ok(restriction.clone());
}
define_list_builder_accessors! {
struct GuardUsageBuilder {
pub restrictions: [GuardRestriction],
}
}
impl GuardUsageBuilder {
/// Create a new empty [`GuardUsageBuilder`].
pub fn new() -> Self {
Self::default()
}
}
/// A restriction that applies to a single request for a guard.
///
/// Restrictions differ from filters (see [`GuardFilter`]) in that
/// they apply to single requests, not to our entire set of guards.
/// They're suitable for things like making sure that we don't start
/// and end a circuit at the same relay, or requiring a specific
/// subprotocol version for certain kinds of requests.
#[derive(Clone, Debug, Serialize, Deserialize)]
#[non_exhaustive]
pub enum GuardRestriction {
/// Don't pick a guard with the provided identity.
AvoidId(RelayId),
/// Don't pick a guard with any of the provided Ed25519 identities.
AvoidAllIds(RelayIdSet),
}
/// The kind of vanguards to use.
#[derive(Debug, Default, Clone, Copy, Eq, PartialEq, Serialize, Deserialize)] //
#[derive(derive_more::Display)] //
#[serde(rename_all = "lowercase")]
#[cfg(feature = "vanguards")]
#[non_exhaustive]
pub enum VanguardMode {
/// "Lite" vanguards.
#[default]
#[display(fmt = "lite")]
Lite,
/// "Full" vanguards.
#[display(fmt = "full")]
Full,
/// Vanguards are disabled.
#[display(fmt = "disabled")]
Disabled,
}
#[cfg(feature = "vanguards")]
impl VanguardMode {
/// Build a `VanguardMode` from a [`NetParameters`] parameter.
///
/// Used for converting [`vanguards_enabled`](NetParameters::vanguards_enabled)
/// or [`vanguards_hs_service`](NetParameters::vanguards_hs_service)
/// to the corresponding `VanguardMode`.
#[allow(dead_code)] // TODO HS-VANGUARDS
pub(crate) fn from_net_parameter(val: BoundedInt32<0, 2>) -> Self {
match val.get() {
0 => VanguardMode::Disabled,
1 => VanguardMode::Lite,
2 => VanguardMode::Full,
_ => unreachable!("BoundedInt32 was not bounded?!"),
}
}
}
/// The kind of vanguards to use.
#[derive(Debug, Default, Clone, Copy, Eq, PartialEq, Serialize, Deserialize)] //
#[derive(derive_more::Display)] //
#[serde(rename_all = "lowercase")]
#[cfg(not(feature = "vanguards"))]
#[non_exhaustive]
pub enum VanguardMode {
/// Vanguards are disabled.
#[default]
#[display(fmt = "disabled")]
Disabled,
}
#[cfg(test)]
mod test {
// @@ begin test lint list maintained by maint/add_warning @@
#![allow(clippy::bool_assert_comparison)]
#![allow(clippy::clone_on_copy)]
#![allow(clippy::dbg_macro)]
#![allow(clippy::mixed_attributes_style)]
#![allow(clippy::print_stderr)]
#![allow(clippy::print_stdout)]
#![allow(clippy::single_char_pattern)]
#![allow(clippy::unwrap_used)]
#![allow(clippy::unchecked_duration_subtraction)]
#![allow(clippy::useless_vec)]
#![allow(clippy::needless_pass_by_value)]
//! <!-- @@ end test lint list maintained by maint/add_warning @@ -->
use super::*;
use tor_linkspec::{HasAddrs, HasRelayIds};
use tor_persist::TestingStateMgr;
use tor_rtcompat::test_with_all_runtimes;
#[test]
fn guard_param_defaults() {
let p1 = GuardParams::default();
let p2: GuardParams = (&NetParameters::default()).try_into().unwrap();
assert_eq!(p1, p2);
}
fn init<R: Runtime>(rt: R) -> (GuardMgr<R>, TestingStateMgr, NetDir) {
use tor_netdir::{testnet, MdReceiver, PartialNetDir};
let statemgr = TestingStateMgr::new();
let have_lock = statemgr.try_lock().unwrap();
assert!(have_lock.held());
let guardmgr = GuardMgr::new(rt, statemgr.clone(), &TestConfig::default()).unwrap();
let (con, mds) = testnet::construct_network().unwrap();
let param_overrides = vec![
// We make the sample size smaller than usual to compensate for the
// small testing network. (Otherwise, we'd sample the whole network,
// and not be able to observe guards in the tests.)
"guard-min-filtered-sample-size=5",
// We choose only two primary guards, to make the tests easier to write.
"guard-n-primary-guards=2",
// We define any restriction that allows 75% or fewer of relays as "meaningful",
// so that we can test the "restrictive" guard sample behavior, and to avoid
"guard-meaningful-restriction-percent=75",
];
let param_overrides: String =
itertools::Itertools::intersperse(param_overrides.into_iter(), " ").collect();
let override_p = param_overrides.parse().unwrap();
let mut netdir = PartialNetDir::new(con, Some(&override_p));
for md in mds {
netdir.add_microdesc(md);
}
let netdir = netdir.unwrap_if_sufficient().unwrap();
(guardmgr, statemgr, netdir)
}
#[test]
#[allow(clippy::clone_on_copy)]
fn simple_case() {
test_with_all_runtimes!(|rt| async move {
let (guardmgr, statemgr, netdir) = init(rt.clone());
let usage = GuardUsage::default();
guardmgr.install_test_netdir(&netdir);
let (id, mon, usable) = guardmgr.select_guard(usage).unwrap();
// Report that the circuit succeeded.
mon.succeeded();
// May we use the circuit?
let usable = usable.await.unwrap();
assert!(usable);
// Save the state...
guardmgr.flush_msg_queue().await;
guardmgr.store_persistent_state().unwrap();
drop(guardmgr);
// Try reloading from the state...
let guardmgr2 =
GuardMgr::new(rt.clone(), statemgr.clone(), &TestConfig::default()).unwrap();
guardmgr2.install_test_netdir(&netdir);
// Since the guard was confirmed, we should get the same one this time!
let usage = GuardUsage::default();
let (id2, _mon, _usable) = guardmgr2.select_guard(usage).unwrap();
assert!(id2.same_relay_ids(&id));
});
}
#[test]
fn simple_waiting() {
// TODO(nickm): This test fails in rare cases; I suspect a
// race condition somewhere.
//
// I've doubled up on the queue flushing in order to try to make the
// race less likely, but we should investigate.
test_with_all_runtimes!(|rt| async move {
let (guardmgr, _statemgr, netdir) = init(rt);
let u = GuardUsage::default();
guardmgr.install_test_netdir(&netdir);
// We'll have the first two guard fail, which should make us
// try a non-primary guard.
let (id1, mon, _usable) = guardmgr.select_guard(u.clone()).unwrap();
mon.failed();
guardmgr.flush_msg_queue().await; // avoid race
guardmgr.flush_msg_queue().await; // avoid race
let (id2, mon, _usable) = guardmgr.select_guard(u.clone()).unwrap();
mon.failed();
guardmgr.flush_msg_queue().await; // avoid race
guardmgr.flush_msg_queue().await; // avoid race
assert!(!id1.same_relay_ids(&id2));
// Now we should get two sampled guards. They should be different.
let (id3, mon3, usable3) = guardmgr.select_guard(u.clone()).unwrap();
let (id4, mon4, usable4) = guardmgr.select_guard(u.clone()).unwrap();
assert!(!id3.same_relay_ids(&id4));
let (u3, u4) = futures::join!(
async {
mon3.failed();
guardmgr.flush_msg_queue().await; // avoid race
usable3.await.unwrap()
},
async {
mon4.succeeded();
usable4.await.unwrap()
}
);
assert_eq!((u3, u4), (false, true));
});
}
#[test]
fn filtering_basics() {
test_with_all_runtimes!(|rt| async move {
let (guardmgr, _statemgr, netdir) = init(rt);
let u = GuardUsage::default();
let filter = {
let mut f = GuardFilter::default();
// All the addresses in the test network are {0,1,2,3,4}.0.0.3:9001.
// Limit to only 2.0.0.0/8
f.push_reachable_addresses(vec!["2.0.0.0/8:9001".parse().unwrap()]);
f
};
guardmgr.set_filter(filter);
guardmgr.install_test_netdir(&netdir);
let (guard, _mon, _usable) = guardmgr.select_guard(u).unwrap();
// Make sure that the filter worked.
let addr = guard.addrs()[0];
assert_eq!(addr, "2.0.0.3:9001".parse().unwrap());
});
}
#[test]
fn external_status() {
test_with_all_runtimes!(|rt| async move {
let (guardmgr, _statemgr, netdir) = init(rt);
let data_usage = GuardUsage::default();
let dir_usage = GuardUsageBuilder::new()
.kind(GuardUsageKind::OneHopDirectory)
.build()
.unwrap();
guardmgr.install_test_netdir(&netdir);
{
// Override this parameter, so that we can get deterministic results below.
let mut inner = guardmgr.inner.lock().unwrap();
inner.params.dir_parallelism = 1;
}
let (guard, mon, _usable) = guardmgr.select_guard(data_usage.clone()).unwrap();
mon.succeeded();
// Record that this guard gave us a bad directory object.
guardmgr.note_external_failure(&guard, ExternalActivity::DirCache);
// We ask for another guard, for data usage. We should get the same
// one as last time, since the director failure doesn't mean this
// guard is useless as a primary guard.
let (g2, mon, _usable) = guardmgr.select_guard(data_usage).unwrap();
assert_eq!(g2.ed_identity(), guard.ed_identity());
mon.succeeded();
// But if we ask for a guard for directory usage, we should get a
// different one, since the last guard we gave out failed.
let (g3, mon, _usable) = guardmgr.select_guard(dir_usage.clone()).unwrap();
assert_ne!(g3.ed_identity(), guard.ed_identity());
mon.succeeded();
// Now record a success for for directory usage.
guardmgr.note_external_success(&guard, ExternalActivity::DirCache);
// Now that the guard is working as a cache, asking for it should get us the same guard.
let (g4, _mon, _usable) = guardmgr.select_guard(dir_usage).unwrap();
assert_eq!(g4.ed_identity(), guard.ed_identity());
});
}
}