systemd.dnssd does not handle local requests (#32991)

systemd.dnssd does not handle local requests Fixes https://github.com/systemd/systemd/issues/32990
2024-07-21 12:48:56 +01:00
parent 9d962e370c
commit a2ae7ed7d0
1 changed files with 4 additions and 1 deletions
@@ -386,7 +386,10 @@ static int on_mdns_packet(sd_event_source *s, int fd, uint32_t revents, void *us
        if (r <= 0)
                return r;

-        if (manager_packet_from_local_address(m, p))
+        /* Refuse traffic from the local host, to avoid query loops. However, allow legacy mDNS
+         * unicast queries through anyway (we never send those ourselves, hence no risk).
+         * i.e. check for the source port nr. */
+        if (p->sender_port == MDNS_PORT && manager_packet_from_local_address(m, p))
                return 0;

        scope = manager_find_scope(m, p);