resolved: rework synthesizing logic

With this change we'll now also generate synthesized RRs for the local
LLMNR hostname (first label of system hostname), the local mDNS hostname
(first label of system hostname suffixed with .local), the "gateway"
hostname and all the reverse PTRs. This hence takes over part of what
nss-myhostname already implemented.

Local hostnames resolve to the set of local IP addresses. Since the
addresses are possibly on different interfaces it is necessary to change
the internal DnsAnswer object to track per-RR interface indexes, and to
change the bus API to always return the interface per-address rather than
per-reply. This change also patches  the existing clients for resolved
accordingly (nss-resolve + systemd-resolve-host).

This also changes the routing logic for queries slightly: we now ensure
that the local hostname is never resolved via LLMNR, thus making it
trustable on the local system.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/resolve/resolved-dns-zone.c b/src/resolve/resolved-dns-zone.c
index 32d771a954..99d96c3f40 100644
--- a/src/resolve/resolved-dns-zone.c
+++ b/src/resolve/resolved-dns-zone.c
@@ -422,7 +422,7 @@ int dns_zone_lookup(DnsZone *z, DnsQuestion *q, DnsAnswer **ret_answer, DnsAnswe
                                 if (k < 0)
                                         return k;
                                 if (k > 0) {
-                                        r = dns_answer_add(answer, j->rr);
+                                        r = dns_answer_add(answer, j->rr, 0);
                                         if (r < 0)
                                                 return r;
 
@@ -448,7 +448,7 @@ int dns_zone_lookup(DnsZone *z, DnsQuestion *q, DnsAnswer **ret_answer, DnsAnswe
                                 if (j->state != DNS_ZONE_ITEM_PROBING)
                                         tentative = false;
 
-                                r = dns_answer_add(answer, j->rr);
+                                r = dns_answer_add(answer, j->rr, 0);
                                 if (r < 0)
                                         return r;
                         }
@@ -505,7 +505,7 @@ void dns_zone_item_conflict(DnsZoneItem *i) {
         i->state = DNS_ZONE_ITEM_WITHDRAWN;
 
         /* Maybe change the hostname */
-        if (dns_name_equal(i->scope->manager->hostname, DNS_RESOURCE_KEY_NAME(i->rr->key)) > 0)
+        if (manager_is_own_hostname(i->scope->manager, DNS_RESOURCE_KEY_NAME(i->rr->key)) > 0)
                 manager_next_hostname(i->scope->manager);
 }