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Improve conflict resolution when adding new bridges.

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This commit is contained in:
George Kadianakis 2012-06-03 00:21:49 +03:00
parent 0cbe3ff313
commit 1e95a4a1f6
1 changed files with 84 additions and 4 deletions
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88
src/or/circuitbuild.c
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@ -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);