Use feature_present(3) to determine whether to open an INET or an

INET6 socket when needed to allow pfctl to work on noinet and noinet6
kernels (and try to provide a fallback using AF_LINK as best effort).
Adjust the Makefile to also respect relevant src.conf(5) options
for compile time decisions on INET and INET6 support.

Reviewed by:	glebius (no objections)
MFC after:	1 week

1 files changed, 22 insertions, 2 deletions

diff --git a/sbin/pfctl/pfctl_parser.c b/sbin/pfctl/pfctl_parser.c
index f248995..1f4375a 100644
--- a/sbin/pfctl/pfctl_parser.c
+++ b/sbin/pfctl/pfctl_parser.c
@@ -1231,6 +1231,26 @@ ifa_load(void)
 	freeifaddrs(ifap);
 }
 
+int
+get_socket_domain(void)
+{
+	int sdom;
+
+	sdom = AF_UNSPEC;
+#ifdef WITH_INET6
+	if (sdom == AF_UNSPEC && feature_present("inet6"))
+		sdom = AF_INET6;
+#endif
+#ifdef WITH_INET
+	if (sdom == AF_UNSPEC && feature_present("inet"))
+		sdom = AF_INET;
+#endif
+	if (sdom == AF_UNSPEC)
+		sdom = AF_LINK;
+
+	return (sdom);
+}
+
 struct node_host *
 ifa_exists(const char *ifa_name)
 {
@@ -1242,7 +1262,7 @@ ifa_exists(const char *ifa_name)
 		ifa_load();
 
 	/* check wether this is a group */
-	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
+	if ((s = socket(get_socket_domain(), SOCK_DGRAM, 0)) == -1)
 		err(1, "socket");
 	bzero(&ifgr, sizeof(ifgr));
 	strlcpy(ifgr.ifgr_name, ifa_name, sizeof(ifgr.ifgr_name));
@@ -1273,7 +1293,7 @@ ifa_grouplookup(const char *ifa_name, int flags)
 	int			 s, len;
 	struct node_host	*n, *h = NULL;
 
-	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
+	if ((s = socket(get_socket_domain(), SOCK_DGRAM, 0)) == -1)
 		err(1, "socket");
 	bzero(&ifgr, sizeof(ifgr));
 	strlcpy(ifgr.ifgr_name, ifa_name, sizeof(ifgr.ifgr_name));