commit 1e95a4a1f6d074e5f5f0033f596dd5ee66eea58a Author: George Kadianakis desnacked@riseup.net Date: Sun Jun 3 00:21:49 2012 +0300

Improve conflict resolution when adding new bridges. --- src/or/circuitbuild.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 84 insertions(+), 4 deletions(-)

diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c index 82ff327..8e7948c 100644 --- a/src/or/circuitbuild.c +++ b/src/or/circuitbuild.c @@ -4912,6 +4912,89 @@ learned_router_identity(const tor_addr_t *addr, uint16_t port, } }

+/** Returns true if <b>bridge</b> has the same identity digest as + * <b>digest</b>. <b>digest</b> is optional in which case it matches + * bridges without identity digests. */ +static int +bridge_has_digest(const bridge_info_t *bridge, const char *digest) +{ + if (!digest && tor_digest_is_zero(bridge->identity)) + return 1; + if (digest && tor_memeq(digest, bridge->identity, DIGEST_LEN)) + return 1; + return 0; +} + +/** Returns true if <b>bridge</b> uses the same pluggable transport as + * <b>transport_name</b>. <b>transport_name</b> is optional in which + * case it matches bridges without pluggable transports. */ +static int +bridge_has_transport_name(const bridge_info_t *bridge, + const char *transport_name) +{ + if (!transport_name && !bridge->transport_name) + return 1; + if (transport_name && !strcmp(transport_name, bridge->transport_name)) + return 1; + return 0; +} + +/** We want to add a new bridge at <b>addr</b>:<b>port</b>, with + * optional <b>digest</b> and <b>transport_name</b>. See if this + * generates any conflicts with already registered bridges, try to + * resolve them and warn the user. + * + * This function might end up marking already registered bridges to + * be deleted. + */ +static void +bridge_resolve_conflicts(const tor_addr_t *addr, uint16_t port, + const char *digest, const char *transport_name) +{ + /** Iterate the already-registered bridge list: + + If you find a bridge with the same adress and port, mark it for + removal. It doesn't make sense to have two active bridges with + the same IP:PORT. If the bridge in question has a different + digest or transport than <b>digest</b>/<b>transport_name</b>, + it's probably a misconfiguration and we should warn the user. + */ + SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge) { + if (bridge->marked_for_removal) + continue; + + if (tor_addr_eq(&bridge->addr, addr) && (bridge->port == port)) { + + bridge->marked_for_removal = 1; + + if (!bridge_has_digest(bridge, digest) || + !bridge_has_transport_name(bridge, transport_name)) { + /* warn the user */ + char *bridge_description_new, *bridge_description_old; + tor_asprintf(&bridge_description_new, "%s:%u:%s:%s", + fmt_addr(addr), port, + digest ? hex_str(digest, DIGEST_LEN) : "", + transport_name ? transport_name : ""); + tor_asprintf(&bridge_description_old, "%s:%u:%s:%s", + fmt_addr(&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); +} + /** Remember a new bridge at <b>addr</b>:<b>port</b>. If <b>digest</b> * is set, it tells us the identity key too. If we already had the * bridge in our list, unmark it, and don't actually add anything new. @@ -4923,10 +5006,7 @@ bridge_add_from_config(const tor_addr_t *addr, uint16_t port, { bridge_info_t *b;

- if ((b = get_configured_bridge_by_addr_port_digest(addr, port, digest))) { - b->marked_for_removal = 0; - return; - } + bridge_resolve_conflicts(addr, port, digest, transport_name);

b = tor_malloc_zero(sizeof(bridge_info_t)); tor_addr_copy(&b->addr, addr);