890 lines
30 KiB
C
890 lines
30 KiB
C
/* Copyright (c) 2001 Matej Pfajfar.
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* Copyright (c) 2001-2004, Roger Dingledine.
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* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
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* Copyright (c) 2007-2017, The Tor Project, Inc. */
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/* See LICENSE for licensing information */
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/**
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* \file bridges.c
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* \brief Code to manage bridges and bridge selection.
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*
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* Bridges are fixed entry nodes, used for censorship circumvention.
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**/
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#include "or.h"
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#include "bridges.h"
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#include "circuitbuild.h"
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#include "config.h"
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#include "connection.h"
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#include "directory.h"
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#include "entrynodes.h"
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#include "nodelist.h"
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#include "policies.h"
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#include "router.h"
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#include "routerlist.h"
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#include "routerset.h"
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#include "transports.h"
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/** Information about a configured bridge. Currently this just matches the
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* ones in the torrc file, but one day we may be able to learn about new
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* bridges on our own, and remember them in the state file. */
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struct bridge_info_t {
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/** Address and port of the bridge, as configured by the user.*/
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tor_addr_port_t addrport_configured;
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/** Address of the bridge. */
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tor_addr_t addr;
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/** TLS port for the bridge. */
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uint16_t port;
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/** Boolean: We are re-parsing our bridge list, and we are going to remove
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* this one if we don't find it in the list of configured bridges. */
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unsigned marked_for_removal : 1;
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/** Expected identity digest, or all zero bytes if we don't know what the
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* digest should be. */
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char identity[DIGEST_LEN];
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/** Name of pluggable transport protocol taken from its config line. */
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char *transport_name;
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/** When should we next try to fetch a descriptor for this bridge? */
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download_status_t fetch_status;
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/** A smartlist of k=v values to be passed to the SOCKS proxy, if
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transports are used for this bridge. */
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smartlist_t *socks_args;
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};
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static void bridge_free(bridge_info_t *bridge);
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/** A list of configured bridges. Whenever we actually get a descriptor
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* for one, we add it as an entry guard. Note that the order of bridges
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* in this list does not necessarily correspond to the order of bridges
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* in the torrc. */
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static smartlist_t *bridge_list = NULL;
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/** Mark every entry of the bridge list to be removed on our next call to
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* sweep_bridge_list unless it has first been un-marked. */
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void
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mark_bridge_list(void)
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{
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if (!bridge_list)
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bridge_list = smartlist_new();
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SMARTLIST_FOREACH(bridge_list, bridge_info_t *, b,
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b->marked_for_removal = 1);
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}
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/** Remove every entry of the bridge list that was marked with
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* mark_bridge_list if it has not subsequently been un-marked. */
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void
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sweep_bridge_list(void)
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{
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if (!bridge_list)
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bridge_list = smartlist_new();
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SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b) {
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if (b->marked_for_removal) {
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SMARTLIST_DEL_CURRENT(bridge_list, b);
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bridge_free(b);
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}
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} SMARTLIST_FOREACH_END(b);
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}
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/** Initialize the bridge list to empty, creating it if needed. */
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static void
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clear_bridge_list(void)
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{
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if (!bridge_list)
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bridge_list = smartlist_new();
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SMARTLIST_FOREACH(bridge_list, bridge_info_t *, b, bridge_free(b));
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smartlist_clear(bridge_list);
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}
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/** Free the bridge <b>bridge</b>. */
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static void
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bridge_free(bridge_info_t *bridge)
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{
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if (!bridge)
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return;
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tor_free(bridge->transport_name);
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if (bridge->socks_args) {
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SMARTLIST_FOREACH(bridge->socks_args, char*, s, tor_free(s));
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smartlist_free(bridge->socks_args);
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}
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tor_free(bridge);
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}
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/** Return a list of all the configured bridges, as bridge_info_t pointers. */
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const smartlist_t *
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bridge_list_get(void)
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{
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if (!bridge_list)
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bridge_list = smartlist_new();
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return bridge_list;
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}
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/**
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* Given a <b>bridge</b>, return a pointer to its RSA identity digest, or
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* NULL if we don't know one for it.
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*/
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const uint8_t *
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bridge_get_rsa_id_digest(const bridge_info_t *bridge)
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{
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tor_assert(bridge);
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if (tor_digest_is_zero(bridge->identity))
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return NULL;
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else
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return (const uint8_t *) bridge->identity;
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}
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/**
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* Given a <b>bridge</b>, return a pointer to its configured addr:port
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* combination.
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*/
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const tor_addr_port_t *
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bridge_get_addr_port(const bridge_info_t *bridge)
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{
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tor_assert(bridge);
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return &bridge->addrport_configured;
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}
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/** If we have a bridge configured whose digest matches <b>digest</b>, or a
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* bridge with no known digest whose address matches any of the
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* tor_addr_port_t's in <b>orports</b>, return that bridge. Else return
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* NULL. */
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static bridge_info_t *
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get_configured_bridge_by_orports_digest(const char *digest,
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const smartlist_t *orports)
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{
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if (!bridge_list)
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return NULL;
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SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge)
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{
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if (tor_digest_is_zero(bridge->identity)) {
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SMARTLIST_FOREACH_BEGIN(orports, tor_addr_port_t *, ap)
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{
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if (tor_addr_compare(&bridge->addr, &ap->addr, CMP_EXACT) == 0 &&
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bridge->port == ap->port)
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return bridge;
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}
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SMARTLIST_FOREACH_END(ap);
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}
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if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN))
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return bridge;
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}
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SMARTLIST_FOREACH_END(bridge);
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return NULL;
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}
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/** If we have a bridge configured whose digest matches <b>digest</b>, or a
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* bridge with no known digest whose address matches <b>addr</b>:<b>port</b>,
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* return that bridge. Else return NULL. If <b>digest</b> is NULL, check for
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* address/port matches only. */
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bridge_info_t *
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get_configured_bridge_by_addr_port_digest(const tor_addr_t *addr,
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uint16_t port,
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const char *digest)
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{
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if (!bridge_list)
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return NULL;
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SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge)
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{
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if ((tor_digest_is_zero(bridge->identity) || digest == NULL) &&
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!tor_addr_compare(&bridge->addr, addr, CMP_EXACT) &&
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bridge->port == port)
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return bridge;
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if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN))
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return bridge;
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}
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SMARTLIST_FOREACH_END(bridge);
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return NULL;
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}
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/**
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* As get_configured_bridge_by_addr_port, but require that the
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* address match <b>addr</b>:<b>port</b>, and that the ID digest match
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* <b>digest</b>. (The other function will ignore the address if the
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* digest matches.)
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*/
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bridge_info_t *
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get_configured_bridge_by_exact_addr_port_digest(const tor_addr_t *addr,
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uint16_t port,
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const char *digest)
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{
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if (!bridge_list)
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return NULL;
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SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) {
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if (!tor_addr_compare(&bridge->addr, addr, CMP_EXACT) &&
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bridge->port == port) {
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if (digest && tor_memeq(bridge->identity, digest, DIGEST_LEN))
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return bridge;
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else if (!digest || tor_digest_is_zero(bridge->identity))
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return bridge;
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}
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} SMARTLIST_FOREACH_END(bridge);
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return NULL;
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}
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/** If we have a bridge configured whose digest matches <b>digest</b>, or a
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* bridge with no known digest whose address matches <b>addr</b>:<b>port</b>,
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* return 1. Else return 0. If <b>digest</b> is NULL, check for
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* address/port matches only. */
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int
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addr_is_a_configured_bridge(const tor_addr_t *addr,
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uint16_t port,
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const char *digest)
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{
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tor_assert(addr);
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return get_configured_bridge_by_addr_port_digest(addr, port, digest) ? 1 : 0;
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}
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/** If we have a bridge configured whose digest matches
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* <b>ei->identity_digest</b>, or a bridge with no known digest whose address
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* matches <b>ei->addr</b>:<b>ei->port</b>, return 1. Else return 0.
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* If <b>ei->onion_key</b> is NULL, check for address/port matches only. */
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int
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extend_info_is_a_configured_bridge(const extend_info_t *ei)
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{
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const char *digest = ei->onion_key ? ei->identity_digest : NULL;
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return addr_is_a_configured_bridge(&ei->addr, ei->port, digest);
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}
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/** Wrapper around get_configured_bridge_by_addr_port_digest() to look
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* it up via router descriptor <b>ri</b>. */
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static bridge_info_t *
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get_configured_bridge_by_routerinfo(const routerinfo_t *ri)
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{
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bridge_info_t *bi = NULL;
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smartlist_t *orports = router_get_all_orports(ri);
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bi = get_configured_bridge_by_orports_digest(ri->cache_info.identity_digest,
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orports);
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SMARTLIST_FOREACH(orports, tor_addr_port_t *, p, tor_free(p));
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smartlist_free(orports);
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return bi;
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}
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/** Return 1 if <b>ri</b> is one of our known bridges, else 0. */
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int
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routerinfo_is_a_configured_bridge(const routerinfo_t *ri)
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{
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return get_configured_bridge_by_routerinfo(ri) ? 1 : 0;
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}
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/** Return 1 if <b>node</b> is one of our configured bridges, else 0. */
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int
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node_is_a_configured_bridge(const node_t *node)
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{
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int retval = 0;
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smartlist_t *orports = node_get_all_orports(node);
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retval = get_configured_bridge_by_orports_digest(node->identity,
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orports) != NULL;
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SMARTLIST_FOREACH(orports, tor_addr_port_t *, p, tor_free(p));
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smartlist_free(orports);
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return retval;
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}
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/** We made a connection to a router at <b>addr</b>:<b>port</b>
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* without knowing its digest. Its digest turned out to be <b>digest</b>.
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* If it was a bridge, and we still don't know its digest, record it.
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*/
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void
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learned_router_identity(const tor_addr_t *addr, uint16_t port,
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const char *digest,
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const ed25519_public_key_t *ed_id)
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{
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// XXXX prop220 use ed_id here, once there is some way to specify
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(void)ed_id;
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int learned = 0;
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bridge_info_t *bridge =
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get_configured_bridge_by_exact_addr_port_digest(addr, port, digest);
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if (bridge && tor_digest_is_zero(bridge->identity)) {
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memcpy(bridge->identity, digest, DIGEST_LEN);
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learned = 1;
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}
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/* XXXX prop220 remember bridge ed25519 identities -- add a field */
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#if 0
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if (bridge && ed_id &&
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ed25519_public_key_is_zero(&bridge->ed25519_identity) &&
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!ed25519_public_key_is_zero(ed_id)) {
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memcpy(&bridge->ed25519_identity, ed_id, sizeof(*ed_id));
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learned = 1;
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}
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#endif
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if (learned) {
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char *transport_info = NULL;
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const char *transport_name =
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find_transport_name_by_bridge_addrport(addr, port);
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if (transport_name)
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tor_asprintf(&transport_info, " (with transport '%s')", transport_name);
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// XXXX prop220 log both fingerprints.
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log_notice(LD_DIR, "Learned fingerprint %s for bridge %s%s.",
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hex_str(digest, DIGEST_LEN), fmt_addrport(addr, port),
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transport_info ? transport_info : "");
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tor_free(transport_info);
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entry_guard_learned_bridge_identity(&bridge->addrport_configured,
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(const uint8_t *)digest);
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}
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}
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/** Return true if <b>bridge</b> has the same identity digest as
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* <b>digest</b>. If <b>digest</b> is NULL, it matches
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* bridges with unspecified identity digests. */
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static int
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bridge_has_digest(const bridge_info_t *bridge, const char *digest)
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{
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if (digest)
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return tor_memeq(digest, bridge->identity, DIGEST_LEN);
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else
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return tor_digest_is_zero(bridge->identity);
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}
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/** We are about to add a new bridge at <b>addr</b>:<b>port</b>, with optional
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* <b>digest</b> and <b>transport_name</b>. Mark for removal any previously
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* existing bridge with the same address and port, and warn the user as
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* appropriate.
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*/
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static void
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bridge_resolve_conflicts(const tor_addr_t *addr, uint16_t port,
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const char *digest, const char *transport_name)
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{
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/* Iterate the already-registered bridge list:
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If you find a bridge with the same adress and port, mark it for
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removal. It doesn't make sense to have two active bridges with
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the same IP:PORT. If the bridge in question has a different
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digest or transport than <b>digest</b>/<b>transport_name</b>,
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it's probably a misconfiguration and we should warn the user.
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*/
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SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) {
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if (bridge->marked_for_removal)
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continue;
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if (tor_addr_eq(&bridge->addr, addr) && (bridge->port == port)) {
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bridge->marked_for_removal = 1;
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if (!bridge_has_digest(bridge, digest) ||
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strcmp_opt(bridge->transport_name, transport_name)) {
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/* warn the user */
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char *bridge_description_new, *bridge_description_old;
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tor_asprintf(&bridge_description_new, "%s:%s:%s",
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fmt_addrport(addr, port),
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digest ? hex_str(digest, DIGEST_LEN) : "",
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transport_name ? transport_name : "");
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tor_asprintf(&bridge_description_old, "%s:%s:%s",
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fmt_addrport(&bridge->addr, bridge->port),
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tor_digest_is_zero(bridge->identity) ?
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"" : hex_str(bridge->identity,DIGEST_LEN),
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bridge->transport_name ? bridge->transport_name : "");
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log_warn(LD_GENERAL,"Tried to add bridge '%s', but we found a conflict"
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" with the already registered bridge '%s'. We will discard"
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" the old bridge and keep '%s'. If this is not what you"
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" wanted, please change your configuration file accordingly.",
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bridge_description_new, bridge_description_old,
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bridge_description_new);
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tor_free(bridge_description_new);
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tor_free(bridge_description_old);
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}
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}
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} SMARTLIST_FOREACH_END(bridge);
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}
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/** Return True if we have a bridge that uses a transport with name
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* <b>transport_name</b>. */
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MOCK_IMPL(int,
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transport_is_needed, (const char *transport_name))
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{
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if (!bridge_list)
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return 0;
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SMARTLIST_FOREACH_BEGIN(bridge_list, const bridge_info_t *, bridge) {
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if (bridge->transport_name &&
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!strcmp(bridge->transport_name, transport_name))
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return 1;
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} SMARTLIST_FOREACH_END(bridge);
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return 0;
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}
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/** Register the bridge information in <b>bridge_line</b> to the
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* bridge subsystem. Steals reference of <b>bridge_line</b>. */
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void
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bridge_add_from_config(bridge_line_t *bridge_line)
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{
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bridge_info_t *b;
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// XXXX prop220 add a way to specify ed25519 ID to bridge_line_t.
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{ /* Log the bridge we are about to register: */
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log_debug(LD_GENERAL, "Registering bridge at %s (transport: %s) (%s)",
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fmt_addrport(&bridge_line->addr, bridge_line->port),
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bridge_line->transport_name ?
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bridge_line->transport_name : "no transport",
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tor_digest_is_zero(bridge_line->digest) ?
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"no key listed" : hex_str(bridge_line->digest, DIGEST_LEN));
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if (bridge_line->socks_args) { /* print socks arguments */
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int i = 0;
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tor_assert(smartlist_len(bridge_line->socks_args) > 0);
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log_debug(LD_GENERAL, "Bridge uses %d SOCKS arguments:",
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smartlist_len(bridge_line->socks_args));
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SMARTLIST_FOREACH(bridge_line->socks_args, const char *, arg,
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log_debug(LD_CONFIG, "%d: %s", ++i, arg));
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}
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}
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bridge_resolve_conflicts(&bridge_line->addr,
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bridge_line->port,
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bridge_line->digest,
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bridge_line->transport_name);
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b = tor_malloc_zero(sizeof(bridge_info_t));
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tor_addr_copy(&b->addrport_configured.addr, &bridge_line->addr);
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b->addrport_configured.port = bridge_line->port;
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tor_addr_copy(&b->addr, &bridge_line->addr);
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b->port = bridge_line->port;
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memcpy(b->identity, bridge_line->digest, DIGEST_LEN);
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if (bridge_line->transport_name)
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b->transport_name = bridge_line->transport_name;
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b->fetch_status.schedule = DL_SCHED_BRIDGE;
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b->fetch_status.backoff = DL_SCHED_RANDOM_EXPONENTIAL;
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b->socks_args = bridge_line->socks_args;
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if (!bridge_list)
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bridge_list = smartlist_new();
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tor_free(bridge_line); /* Deallocate bridge_line now. */
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smartlist_add(bridge_list, b);
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}
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/** If <b>digest</b> is one of our known bridges, return it. */
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bridge_info_t *
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find_bridge_by_digest(const char *digest)
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{
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if (! bridge_list)
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return NULL;
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SMARTLIST_FOREACH(bridge_list, bridge_info_t *, bridge,
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{
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if (tor_memeq(bridge->identity, digest, DIGEST_LEN))
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return bridge;
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});
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return NULL;
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}
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|
|
/** 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;
|
|
}
|
|
|
|
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)
|
|
{
|
|
if (!download_status_is_ready(&bridge->fetch_status, now,
|
|
IMPOSSIBLE_TO_DOWNLOAD))
|
|
continue; /* don't bother, no need to retry yet */
|
|
if (routerset_contains_bridge(options->ExcludeNodes, bridge)) {
|
|
download_status_mark_impossible(&bridge->fetch_status);
|
|
log_warn(LD_APP, "Not using bridge at %s: it is in ExcludeNodes.",
|
|
safe_str_client(fmt_and_decorate_addr(&bridge->addr)));
|
|
continue;
|
|
}
|
|
|
|
/* schedule another fetch as if this one will fail, in case it does */
|
|
download_status_failed(&bridge->fetch_status, 0);
|
|
|
|
can_use_bridge_authority = !tor_digest_is_zero(bridge->identity) &&
|
|
num_bridge_auths;
|
|
ask_bridge_directly = !can_use_bridge_authority ||
|
|
!options->UpdateBridgesFromAuthority;
|
|
log_debug(LD_DIR, "ask_bridge_directly=%d (%d, %d, %d)",
|
|
ask_bridge_directly, tor_digest_is_zero(bridge->identity),
|
|
!options->UpdateBridgesFromAuthority, !num_bridge_auths);
|
|
|
|
if (ask_bridge_directly &&
|
|
!fascist_firewall_allows_address_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) {
|
|
/* they match, so no need to do anything */
|
|
} else {
|
|
rs->addr = tor_addr_to_ipv4h(&bridge->addr);
|
|
rs->or_port = bridge->port;
|
|
log_info(LD_DIR,
|
|
"Adjusted bridge routerstatus for '%s' to match "
|
|
"configured address %s.",
|
|
rs->nickname, fmt_addrport(&bridge->addr, rs->or_port));
|
|
}
|
|
}
|
|
}
|
|
|
|
/** We just learned a descriptor for a bridge. See if that
|
|
* digest is in our entry guard list, and add it if not. */
|
|
void
|
|
learned_bridge_descriptor(routerinfo_t *ri, int from_cache)
|
|
{
|
|
tor_assert(ri);
|
|
tor_assert(ri->purpose == ROUTER_PURPOSE_BRIDGE);
|
|
if (get_options()->UseBridges) {
|
|
int first = num_bridges_usable() <= 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)
|
|
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));
|
|
/* set entry->made_contact so if it goes down we don't drop it from
|
|
* our entry node list */
|
|
if (first) {
|
|
routerlist_retry_directory_downloads(now);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/** Return the number of bridges that have descriptors that
|
|
* are marked with purpose 'bridge' and are running.
|
|
*
|
|
* We use this function to decide if we're ready to start building
|
|
* circuits through our bridges, or if we need to wait until the
|
|
* directory "server/authority" requests finish. */
|
|
int
|
|
any_bridge_descriptors_known(void)
|
|
{
|
|
tor_assert(get_options()->UseBridges);
|
|
|
|
if (!bridge_list)
|
|
return 0;
|
|
|
|
SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) {
|
|
const node_t *node;
|
|
if (!tor_digest_is_zero(bridge->identity) &&
|
|
(node = node_get_by_id(bridge->identity)) != NULL &&
|
|
node->ri) {
|
|
return 1;
|
|
}
|
|
} SMARTLIST_FOREACH_END(bridge);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/** 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;
|
|
}
|
|
|