resolved-dns-query: remove dns_query_candidate_is_routable

flokli · poettering · commit 90bdc8be6676 · 2020-05-26T19:30:23.000+02:00
Resolved can't reliably determine on whether "it makes sense" to query AAAA records when not explicitly specifying it in the request, so we shouldn't remove them. After having done the resolving, applications can use RFC6724 to determine whether that address is reachable. We can't know whether an address is reachable before having resolved it and inspecting the routing table, and not resolving AAAA just because there's no IPv6 default route on the main interface link them breaks various setups, including IPv6-providing wireguard tunnels on a non-dualstacked environment. Fixes systemd#5782 Fixes systemd#5915 Fixes systemd#8017
diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
@@ -212,31 +212,6 @@ static DnsTransactionState dns_query_candidate_state(DnsQueryCandidate *c) {
         return state;
 }
 
-static bool dns_query_candidate_is_routable(DnsQueryCandidate *c, uint16_t type) {
-        int family;
-
-        assert(c);
-
-        /* Checks whether the specified RR type matches an address family that is routable on the link(s) the scope of
-         * this candidate belongs to. Specifically, whether there's a routable IPv4 address on it if we query an A RR,
-         * or a routable IPv6 address if we query an AAAA RR. */
-
-        if (!c->query->suppress_unroutable_family)
-                return true;
-
-        if (c->scope->protocol != DNS_PROTOCOL_DNS)
-                return true;
-
-        family = dns_type_to_af(type);
-        if (family < 0)
-                return true;
-
-        if (c->scope->link)
-                return link_relevant(c->scope->link, family, false);
-        else
-                return manager_routable(c->scope->manager, family);
-}
-
 static int dns_query_candidate_setup_transactions(DnsQueryCandidate *c) {
         DnsQuestion *question;
         DnsResourceKey *key;
@@ -253,9 +228,6 @@ static int dns_query_candidate_setup_transactions(DnsQueryCandidate *c) {
                 _cleanup_(dns_resource_key_unrefp) DnsResourceKey *new_key = NULL;
                 DnsResourceKey *qkey;
 
-                if (!dns_query_candidate_is_routable(c, key->type))
-                        continue;
-
                 if (c->search_domain) {
                         r = dns_resource_key_new_append_suffix(&new_key, key, c->search_domain->name);
                         if (r < 0)
