vxlan: add support for collect metadata flag

This patch add support for IFLA_VXLAN_COLLECT_METADATA via the
'external' keyword to the vxlan link.

Also enforce mutual exclusion between 'vni' and 'external'.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

ip/iplink_vxlan.c

@@ -31,7 +31,7 @@ static void print_explain(FILE *f)
 	fprintf(f, "                 [ ageing SECONDS ] [ maxaddress NUMBER ]\n");
 	fprintf(f, "                 [ [no]udpcsum ] [ [no]udp6zerocsumtx ] [ [no]udp6zerocsumrx ]\n");
 	fprintf(f, "                 [ [no]remcsumtx ] [ [no]remcsumrx ]\n");
-	fprintf(f, "                 [ gbp ]\n");
+	fprintf(f, "                 [ [no]external ] [ gbp ]\n");
 	fprintf(f, "\n");
 	fprintf(f, "Where: VNI := 0-16777215\n");
 	fprintf(f, "       ADDR := { IP_ADDRESS | any }\n");
@@ -72,6 +72,7 @@ static int vxlan_parse_opt(struct link_util *lu, int argc, char **argv,
 	__u8 udp6zerocsumrx = 0;
 	__u8 remcsumtx = 0;
 	__u8 remcsumrx = 0;
+	__u8 metadata = 0;
 	__u8 gbp = 0;
 	int dst_port_set = 0;
 	struct ifla_vxlan_port_range range = { 0, 0 };
@@ -210,6 +211,10 @@ static int vxlan_parse_opt(struct link_util *lu, int argc, char **argv,
 			remcsumrx = 1;
 		} else if (!matches(*argv, "noremcsumrx")) {
 			remcsumrx = 0;
+		} else if (!matches(*argv, "external")) {
+			metadata = 1;
+		} else if (!matches(*argv, "noexternal")) {
+			metadata = 0;
 		} else if (!matches(*argv, "gbp")) {
 			gbp = 1;
 		} else if (matches(*argv, "help") == 0) {
@@ -223,7 +228,12 @@ static int vxlan_parse_opt(struct link_util *lu, int argc, char **argv,
 		argc--, argv++;
 	}
 
-	if (!vni_set) {
+	if (metadata && vni_set) {
+		fprintf(stderr, "vxlan: both 'external' and vni cannot be specified\n");
+		return -1;
+	}
+
+	if (!metadata && !vni_set) {
 		fprintf(stderr, "vxlan: missing virtual network identifier\n");
 		return -1;
 	}
@@ -272,6 +282,7 @@ static int vxlan_parse_opt(struct link_util *lu, int argc, char **argv,
 	addattr8(n, 1024, IFLA_VXLAN_UDP_ZERO_CSUM6_RX, udp6zerocsumrx);
 	addattr8(n, 1024, IFLA_VXLAN_REMCSUM_TX, remcsumtx);
 	addattr8(n, 1024, IFLA_VXLAN_REMCSUM_RX, remcsumrx);
+	addattr8(n, 1024, IFLA_VXLAN_COLLECT_METADATA, metadata);
 
 	if (noage)
 		addattr32(n, 1024, IFLA_VXLAN_AGEING, 0);
@@ -428,6 +439,10 @@ static void vxlan_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 	    rta_getattr_u8(tb[IFLA_VXLAN_REMCSUM_RX]))
 		fputs("remcsumrx ", f);
 
+	if (tb[IFLA_VXLAN_COLLECT_METADATA] &&
+	    rta_getattr_u8(tb[IFLA_VXLAN_COLLECT_METADATA]))
+		fputs("external ", f);
+
 	if (tb[IFLA_VXLAN_GBP])
 		fputs("gbp ", f);
 }