From a2ae7ed7d05ceabb5c0860288d553ab50d466565 Mon Sep 17 00:00:00 2001 From: Alain Greppin Date: Sun, 21 Jul 2024 13:48:56 +0200 Subject: [PATCH] systemd.dnssd does not handle local requests (#32991) systemd.dnssd does not handle local requests Fixes https://github.com/systemd/systemd/issues/32990 --- src/resolve/resolved-mdns.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/resolve/resolved-mdns.c b/src/resolve/resolved-mdns.c index 8f93af38cff..0fb83a3c229 100644 --- a/src/resolve/resolved-mdns.c +++ b/src/resolve/resolved-mdns.c @@ -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); -- 2.47.3