From 877884fc0da76170dce5abe7b3883eee334156b1 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 6 Nov 2020 10:26:44 +0100 Subject: [PATCH] resolved: synthesize NODATA instead of NXDOMAIN if gateway exists, but of other protocol Fixes: #11192 --- src/resolve/resolved-dns-synthesize.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/src/resolve/resolved-dns-synthesize.c b/src/resolve/resolved-dns-synthesize.c index 67f0dda246..f08d62116a 100644 --- a/src/resolve/resolved-dns-synthesize.c +++ b/src/resolve/resolved-dns-synthesize.c @@ -322,8 +322,24 @@ static int synthesize_gateway_rr(Manager *m, const DnsResourceKey *key, int ifin af = dns_type_to_af(key->type); if (af >= 0) { n = local_gateways(m->rtnl, ifindex, af, &addresses); - if (n <= 0) - return n; /* < 0 means: error; == 0 means we have no gateway */ + if (n < 0) /* < 0 means: error */ + return n; + + if (n == 0) { /* == 0 means we have no gateway */ + /* See if there's a gateway on the other protocol */ + if (af == AF_INET) + n = local_gateways(m->rtnl, ifindex, AF_INET6, NULL); + else { + assert(af == AF_INET6); + n = local_gateways(m->rtnl, ifindex, AF_INET, NULL); + } + if (n <= 0) /* error (if < 0) or really no gateway at all (if == 0) */ + return n; + + /* We have a gateway on the other protocol. Let's return > 0 without adding any RR to + * the answer, i.e. synthesize NODATA (and not NXDOMAIN!) */ + return 1; + } } r = answer_add_addresses_rr(answer, dns_resource_key_name(key), addresses, n);