Merge branch 'bug5603'

  o Minor bugfixes:

    - When told to add a bridge with the same addr:port as a

      preexisting bridge but a different transport, change the

      transport as requested. Previously we would not notice the

      change. Fix for bug 5603; fix on 0.2.3.2-alpha.

    - When told to add a bridge with the same digest as a

      preexisting bridge but a different addr:port, change the

      addr:port as requested. Previously we would not notice the

      change. Fix for bug 5603; fix on 0.2.2.26-beta.

  }

}

/** 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 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) ||

          strcmp_opt(bridge->transport_name, 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.

{

  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);