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- /* Copyright (c) 2001 Matej Pfajfar.
- * Copyright (c) 2001-2004, Roger Dingledine.
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2019, 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.
- **/
- #define TOR_BRIDGES_PRIVATE
- #include "core/or/or.h"
- #include "app/config/config.h"
- #include "core/mainloop/connection.h"
- #include "core/or/circuitbuild.h"
- #include "core/or/policies.h"
- #include "feature/client/bridges.h"
- #include "feature/client/entrynodes.h"
- #include "feature/client/transports.h"
- #include "feature/dirclient/dirclient.h"
- #include "feature/dirclient/dlstatus.h"
- #include "feature/dircommon/directory.h"
- #include "feature/nodelist/describe.h"
- #include "feature/nodelist/dirlist.h"
- #include "feature/nodelist/nodelist.h"
- #include "feature/nodelist/routerinfo.h"
- #include "feature/nodelist/routerlist.h"
- #include "feature/nodelist/routerset.h"
- #include "core/or/extend_info_st.h"
- #include "feature/nodelist/node_st.h"
- #include "feature/nodelist/routerinfo_st.h"
- #include "feature/nodelist/routerstatus_st.h"
- #include "feature/nodelist/microdesc_st.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 iff <b>bridge_list</b> contains entry matching
- * given; IPv4 address in host byte order (<b>ipv4_addr</b>
- * and <b>port</b> (and no identity digest) OR it contains an
- * entry whose identity matches <b>digest</b>. Otherwise,
- * return 0.
- */
- static int
- bridge_exists_with_ipv4h_addr_and_port(const uint32_t ipv4_addr,
- const uint16_t port,
- const char *digest)
- {
- tor_addr_t node_ipv4;
- if (tor_addr_port_is_valid_ipv4h(ipv4_addr, port, 0)) {
- tor_addr_from_ipv4h(&node_ipv4, ipv4_addr);
- bridge_info_t *bridge =
- get_configured_bridge_by_addr_port_digest(&node_ipv4,
- port,
- digest);
- return (bridge != NULL);
- }
- return 0;
- }
- /**
- * Return 1 iff <b>bridge_list</b> contains entry matching given
- * <b>ipv6_addr</b> and <b>port</b> (and no identity digest) OR
- * it contains an entry whose identity matches <b>digest</b>.
- * Otherwise, return 0.
- */
- static int
- bridge_exists_with_ipv6_addr_and_port(const tor_addr_t *ipv6_addr,
- const uint16_t port,
- const char *digest)
- {
- if (!tor_addr_port_is_valid(ipv6_addr, port, 0))
- return 0;
- bridge_info_t *bridge =
- get_configured_bridge_by_addr_port_digest(ipv6_addr,
- port,
- digest);
- return (bridge != NULL);
- }
- /** Return 1 if <b>node</b> is one of our configured bridges, else 0.
- * More specifically, return 1 iff: a bridge_info_t object exists in
- * <b>bridge_list</b> such that: 1) It's identity is equal to node
- * identity OR 2) It's identity digest is zero, but it matches
- * address and port of any ORPort in the node.
- */
- int
- node_is_a_configured_bridge(const node_t *node)
- {
- /* First, let's try searching for a bridge with matching identity. */
- if (BUG(fast_mem_is_zero(node->identity, DIGEST_LEN)))
- return 0;
- if (find_bridge_by_digest(node->identity) != NULL)
- return 1;
- /* At this point, we have established that no bridge exists with
- * matching identity digest. However, we still pass it into
- * bridge_exists_* functions because we want further code to
- * check for absence of identity digest in a bridge.
- */
- if (node->ri) {
- if (bridge_exists_with_ipv4h_addr_and_port(node->ri->addr,
- node->ri->or_port,
- node->identity))
- return 1;
- if (bridge_exists_with_ipv6_addr_and_port(&node->ri->ipv6_addr,
- node->ri->ipv6_orport,
- node->identity))
- return 1;
- } else if (node->rs) {
- if (bridge_exists_with_ipv4h_addr_and_port(node->rs->addr,
- node->rs->or_port,
- node->identity))
- return 1;
- if (bridge_exists_with_ipv6_addr_and_port(&node->rs->ipv6_addr,
- node->rs->ipv6_orport,
- node->identity))
- return 1;
- } else if (node->md) {
- if (bridge_exists_with_ipv6_addr_and_port(&node->md->ipv6_addr,
- node->md->ipv6_orport,
- node->identity))
- return 1;
- }
- return 0;
- }
- /** 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. */
- STATIC 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 ||
- options->ClientAutoIPv6ORPort == 0) {
- /* 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;
- }
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