diff options
Diffstat (limited to 'src/or/bridges.c')
| -rw-r--r-- | src/or/bridges.c | 930 |
1 files changed, 930 insertions, 0 deletions
diff --git a/src/or/bridges.c b/src/or/bridges.c new file mode 100644 index 0000000000..29d00f37ba --- /dev/null +++ b/src/or/bridges.c @@ -0,0 +1,930 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2017, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file bridges.c + * \brief Code to manage bridges and bridge selection. + * + * Bridges are fixed entry nodes, used for censorship circumvention. + **/ + +#include "or.h" +#include "bridges.h" +#include "circuitbuild.h" +#include "config.h" +#include "connection.h" +#include "directory.h" +#include "entrynodes.h" +#include "nodelist.h" +#include "policies.h" +#include "router.h" +#include "routerlist.h" +#include "routerset.h" +#include "transports.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. */ +struct bridge_info_t { + /** Address and port of the bridge, as configured by the user.*/ + tor_addr_port_t addrport_configured; + /** 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; +}; + +#define bridge_free(bridge) \ + FREE_AND_NULL(bridge_info_t, bridge_free_, (bridge)) + +static void bridge_free_(bridge_info_t *bridge); +static void rewrite_node_address_for_bridge(const bridge_info_t *bridge, + node_t *node); + +/** 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); +} + +/** Return a list of all the configured bridges, as bridge_info_t pointers. */ +const smartlist_t * +bridge_list_get(void) +{ + if (!bridge_list) + bridge_list = smartlist_new(); + return bridge_list; +} + +/** + * Given a <b>bridge</b>, return a pointer to its RSA identity digest, or + * NULL if we don't know one for it. + */ +const uint8_t * +bridge_get_rsa_id_digest(const bridge_info_t *bridge) +{ + tor_assert(bridge); + if (tor_digest_is_zero(bridge->identity)) + return NULL; + else + return (const uint8_t *) bridge->identity; +} + +/** + * Given a <b>bridge</b>, return a pointer to its configured addr:port + * combination. + */ +const tor_addr_port_t * +bridge_get_addr_port(const bridge_info_t *bridge) +{ + tor_assert(bridge); + return &bridge->addrport_configured; +} + +/** 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. */ +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; +} + +/** + * As get_configured_bridge_by_addr_port, but require that the + * address match <b>addr</b>:<b>port</b>, and that the ID digest match + * <b>digest</b>. (The other function will ignore the address if the + * digest matches.) + */ +bridge_info_t * +get_configured_bridge_by_exact_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_addr_compare(&bridge->addr, addr, CMP_EXACT) && + bridge->port == port) { + + if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN)) + return bridge; + else if (!digest || tor_digest_is_zero(bridge->identity)) + 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 1. Else return 0. If <b>digest</b> is NULL, check for + * address/port matches only. */ +int +addr_is_a_configured_bridge(const tor_addr_t *addr, + uint16_t port, + const char *digest) +{ + tor_assert(addr); + return get_configured_bridge_by_addr_port_digest(addr, port, digest) ? 1 : 0; +} + +/** If we have a bridge configured whose digest matches + * <b>ei->identity_digest</b>, or a bridge with no known digest whose address + * matches <b>ei->addr</b>:<b>ei->port</b>, return 1. Else return 0. + * If <b>ei->onion_key</b> is NULL, check for address/port matches only. */ +int +extend_info_is_a_configured_bridge(const extend_info_t *ei) +{ + const char *digest = ei->onion_key ? ei->identity_digest : NULL; + return addr_is_a_configured_bridge(&ei->addr, ei->port, digest); +} + +/** 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, + const ed25519_public_key_t *ed_id) +{ + // XXXX prop220 use ed_id here, once there is some way to specify + (void)ed_id; + int learned = 0; + bridge_info_t *bridge = + get_configured_bridge_by_exact_addr_port_digest(addr, port, digest); + if (bridge && tor_digest_is_zero(bridge->identity)) { + memcpy(bridge->identity, digest, DIGEST_LEN); + learned = 1; + } + /* XXXX prop220 remember bridge ed25519 identities -- add a field */ +#if 0 + if (bridge && ed_id && + ed25519_public_key_is_zero(&bridge->ed25519_identity) && + !ed25519_public_key_is_zero(ed_id)) { + memcpy(&bridge->ed25519_identity, ed_id, sizeof(*ed_id)); + learned = 1; + } +#endif /* 0 */ + if (learned) { + 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); + + // XXXX prop220 log both fingerprints. + 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); + entry_guard_learned_bridge_identity(&bridge->addrport_configured, + (const uint8_t *)digest); + } +} + +/** 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 address 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>. */ +MOCK_IMPL(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; + + // XXXX prop220 add a way to specify ed25519 ID to bridge_line_t. + + { /* 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->addrport_configured.addr, &bridge_line->addr); + b->addrport_configured.port = bridge_line->port; + 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->fetch_status.increment_on = DL_SCHED_INCREMENT_ATTEMPT; + /* We can't reset the bridge's download status here, because UseBridges + * might be 0 now, and it might be changed to 1 much later. */ + 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); +} + +/** If <b>digest</b> is one of our known bridges, return it. */ +bridge_info_t * +find_bridge_by_digest(const char *digest) +{ + if (! bridge_list) + return NULL; + 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(); + circuit_guard_state_t *guard_state = NULL; + + 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; + } + + /* Until we get a descriptor for the bridge, we only know one address for + * it. */ + if (!fascist_firewall_allows_address_addr(&bridge->addr, bridge->port, + FIREWALL_OR_CONNECTION, 0, 0)) { + log_notice(LD_CONFIG, "Tried to fetch a descriptor directly from a " + "bridge, but that bridge is not reachable through our " + "firewall."); + return; + } + + /* If we already have a node_t for this bridge, rewrite its address now. */ + node_t *node = node_get_mutable_by_id(bridge->identity); + if (node) { + rewrite_node_address_for_bridge(bridge, node); + } + + tor_addr_port_t bridge_addrport; + memcpy(&bridge_addrport.addr, &bridge->addr, sizeof(tor_addr_t)); + bridge_addrport.port = bridge->port; + + guard_state = get_guard_state_for_bridge_desc_fetch(bridge->identity); + + directory_request_t *req = + directory_request_new(DIR_PURPOSE_FETCH_SERVERDESC); + directory_request_set_or_addr_port(req, &bridge_addrport); + directory_request_set_directory_id_digest(req, bridge->identity); + directory_request_set_router_purpose(req, ROUTER_PURPOSE_BRIDGE); + directory_request_set_resource(req, "authority.z"); + if (guard_state) { + directory_request_set_guard_state(req, guard_state); + } + directory_initiate_request(req); + directory_request_free(req); +} + +/** 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) + { + /* This resets the download status on first use */ + if (!download_status_is_ready(&bridge->fetch_status, now)) + 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 the next attempt + * we can't increment after a failure, because sometimes we use the + * bridge authority, and sometimes we use the bridge direct */ + download_status_increment_attempt( + &bridge->fetch_status, + safe_str_client(fmt_and_decorate_addr(&bridge->addr)), + now); + + 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_addr(&bridge->addr, bridge->port, + FIREWALL_OR_CONNECTION, 0, + 0)) { + 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, DL_WANT_AUTHORITY); + } + } + 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; + const or_options_t *options = get_options(); + + 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; + } + } + + if (options->ClientPreferIPv6ORPort == -1) { + /* 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)); + } else { + /* Mark which address to use based on user preference */ + node->ipv6_preferred = (fascist_firewall_prefer_ipv6_orport(options) && + !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) based on %s.", + ri->nickname, + node->ipv6_preferred ? "IPv6" : "IPv4", + fmt_addrport(&ap.addr, ap.port), + options->ClientPreferIPv6ORPort == -1 ? + "the configured Bridge address" : + "ClientPreferIPv6ORPort"); + } + } + 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) || + (!tor_addr_compare(&bridge->addr, &rs->ipv6_addr, CMP_EXACT) && + bridge->port == rs->ipv6_orport)) { + /* they match, so no need to do anything */ + } else { + if (tor_addr_family(&bridge->addr) == AF_INET) { + 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)); + /* set IPv6 preferences even if there is no ri */ + } else if (tor_addr_family(&bridge->addr) == AF_INET6) { + tor_addr_copy(&rs->ipv6_addr, &bridge->addr); + rs->ipv6_orport = bridge->port; + log_info(LD_DIR, + "Adjusted bridge routerstatus for '%s' to match configured" + " address %s.", + rs->nickname, fmt_addrport(&rs->ipv6_addr, rs->ipv6_orport)); + } else { + log_err(LD_BUG, "Address family not supported: %d.", + tor_addr_family(&bridge->addr)); + return; + } + } + + if (options->ClientPreferIPv6ORPort == -1) { + /* 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->rs->ipv6_addr)); + } else { + /* Mark which address to use based on user preference */ + node->ipv6_preferred = (fascist_firewall_prefer_ipv6_orport(options) && + !tor_addr_is_null(&node->rs->ipv6_addr)); + } + + /* XXXipv6 we lack support for falling back to another address for + the same relay, warn the user */ + if (!tor_addr_is_null(&rs->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) based on %s.", + rs->nickname, + node->ipv6_preferred ? "IPv6" : "IPv4", + fmt_addrport(&ap.addr, ap.port), + options->ClientPreferIPv6ORPort == -1 ? + "the configured Bridge address" : + "ClientPreferIPv6ORPort"); + } + } +} + +/** 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) { + /* Retry directory downloads whenever we get a bridge descriptor: + * - when bootstrapping, and + * - when we aren't sure if any of our bridges are reachable. + * Keep on retrying until we have at least one reachable bridge. */ + int first = num_bridges_usable(0) < 1; + 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) { + /* This schedules the re-fetch at a constant interval, which produces + * a pattern of bridge traffic. But it's better than trying all + * configured briges several times in the first few minutes. */ + 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); + if (tor_digest_is_zero(bridge->identity)) { + memcpy(bridge->identity,ri->cache_info.identity_digest, DIGEST_LEN); + log_notice(LD_DIR, "Learned identity %s for bridge at %s:%d", + hex_str(bridge->identity, DIGEST_LEN), + fmt_and_decorate_addr(&bridge->addr), + (int) bridge->port); + } + entry_guard_learned_bridge_identity(&bridge->addrport_configured, + (const uint8_t*)ri->cache_info.identity_digest); + + log_notice(LD_DIR, "new bridge descriptor '%s' (%s): %s", ri->nickname, + from_cache ? "cached" : "fresh", router_describe(ri)); + /* If we didn't have a reachable bridge before this one, try directory + * documents again. */ + if (first) { + routerlist_retry_directory_downloads(now); + } + } + } +} + +/** Return a smartlist containing all bridge identity digests */ +MOCK_IMPL(smartlist_t *, +list_bridge_identities, (void)) +{ + smartlist_t *result = NULL; + char *digest_tmp; + + if (get_options()->UseBridges && bridge_list) { + result = smartlist_new(); + + SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b) { + digest_tmp = tor_malloc(DIGEST_LEN); + memcpy(digest_tmp, b->identity, DIGEST_LEN); + smartlist_add(result, digest_tmp); + } SMARTLIST_FOREACH_END(b); + } + + return result; +} + +/** Get the download status for a bridge descriptor given its identity */ +MOCK_IMPL(download_status_t *, +get_bridge_dl_status_by_id, (const char *digest)) +{ + download_status_t *dl = NULL; + + if (digest && get_options()->UseBridges && bridge_list) { + SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b) { + if (tor_memeq(digest, b->identity, DIGEST_LEN)) { + dl = &(b->fetch_status); + break; + } + } SMARTLIST_FOREACH_END(b); + } + + return dl; +} + +/** Release all storage held in bridges.c */ +void +bridges_free_all(void) +{ + clear_bridge_list(); + smartlist_free(bridge_list); + bridge_list = NULL; +} + |