resolved: never attempt negative caching of SOA records

[elogind.git] / src / resolve / resolved-dns-scope.c

diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c
index b226f5a457cf3eacb37cc2913b0a30b7e4813995..b17de0c88fdd3f6febf869b1c05496d1b77af3ca 100644 (file)
--- a/src/resolve/resolved-dns-scope.c
+++ b/src/resolve/resolved-dns-scope.c
@@ -254,7 +254,7 @@ int dns_scope_tcp_socket(DnsScope *s, int family, const union in_addr_union *add
         }
 
         if (s->protocol == DNS_PROTOCOL_LLMNR) {
-                /* RFC 4795, section 2.5 suggests the TTL to be set to 1 */
+                /* RFC 4795, section 2.5 requires the TTL to be set to 1 */
 
                 if (sa.sa.sa_family == AF_INET) {
                         r = setsockopt(fd, IPPROTO_IP, IP_TTL, &one, sizeof(one));
@@ -452,6 +452,18 @@ void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) {
         if (p->protocol != DNS_PROTOCOL_LLMNR)
                 return;
 
+        if (p->ipproto == IPPROTO_UDP) {
+                /* Don't accept UDP queries directed to anything but
+                 * the LLMNR multicast addresses. See RFC 4795,
+                 * section 2.5.*/
+
+                if (p->family == AF_INET && !in_addr_equal(AF_INET, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV4_ADDRESS))
+                        return;
+
+                if (p->family == AF_INET6 && !in_addr_equal(AF_INET6, &p->destination, (union in_addr_union*) &LLMNR_MULTICAST_IPV6_ADDRESS))
+                        return;
+        }
+
         r = dns_packet_extract(p);
         if (r < 0) {
                 log_debug("Failed to extract resources from incoming packet: %s", strerror(-r));
@@ -471,6 +483,8 @@ void dns_scope_process_query(DnsScope *s, DnsStream *stream, DnsPacket *p) {
         if (r == 0)
                 return;
 
+        dns_answer_order_by_scope(answer, in_addr_is_link_local(p->family, &p->sender) > 0);
+
         r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, p->question, answer, &reply);
         if (r < 0) {
                 log_debug("Failed to build reply packet: %s", strerror(-r));