iptnl: add support for collect_md flag in IPv4 and IPv6 tunnels

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/ip/link_ip6tnl.c b/ip/link_ip6tnl.c
index 59162a3..051c89f 100644
--- a/ip/link_ip6tnl.c
+++ b/ip/link_ip6tnl.c
@@ -40,6 +40,7 @@
 	fprintf(f, "          [ noencap ] [ encap { fou | gue | none } ]\n");
 	fprintf(f, "          [ encap-sport PORT ] [ encap-dport PORT ]\n");
 	fprintf(f, "          [ [no]encap-csum ] [ [no]encap-csum6 ] [ [no]encap-remcsum ]\n");
+	fprintf(f, "          [ external ]\n");
 	fprintf(f, "\n");
 	fprintf(f, "Where: NAME      := STRING\n");
 	fprintf(f, "       ADDR      := IPV6_ADDRESS\n");
@@ -89,6 +90,7 @@
 	__u16 encapflags = TUNNEL_ENCAP_FLAG_CSUM6;
 	__u16 encapsport = 0;
 	__u16 encapdport = 0;
+	__u8 metadata = 0;
 
 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 		if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 0) {
@@ -141,6 +143,8 @@
 
 		if (iptuninfo[IFLA_IPTUN_PROTO])
 			proto = rta_getattr_u8(iptuninfo[IFLA_IPTUN_PROTO]);
+		if (iptuninfo[IFLA_IPTUN_COLLECT_METADATA])
+			metadata = 1;
 	}
 
 	while (argc > 0) {
@@ -277,12 +281,18 @@
 			encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
 		} else if (strcmp(*argv, "noencap-remcsum") == 0) {
 			encapflags |= ~TUNNEL_ENCAP_FLAG_REMCSUM;
+		} else if (strcmp(*argv, "external") == 0) {
+			metadata = 1;
 		} else
 			usage();
 		argc--, argv++;
 	}
 
 	addattr8(n, 1024, IFLA_IPTUN_PROTO, proto);
+	if (metadata) {
+		addattr_l(n, 1024, IFLA_IPTUN_COLLECT_METADATA, NULL, 0);
+		return 0;
+	}
 	addattr_l(n, 1024, IFLA_IPTUN_LOCAL, &laddr, sizeof(laddr));
 	addattr_l(n, 1024, IFLA_IPTUN_REMOTE, &raddr, sizeof(raddr));
 	addattr8(n, 1024, IFLA_IPTUN_TTL, hop_limit);
diff --git a/ip/link_iptnl.c b/ip/link_iptnl.c
index 7ec3777..1875348 100644
--- a/ip/link_iptnl.c
+++ b/ip/link_iptnl.c
@@ -36,6 +36,7 @@
 		fprintf(f, "          [ mode { ip6ip | ipip | any } ]\n");
 		fprintf(f, "          [ isatap ]\n");
 	}
+	fprintf(f, "          [ external ]\n");
 	fprintf(f, "\n");
 	fprintf(f, "Where: NAME := STRING\n");
 	fprintf(f, "       ADDR := { IP_ADDRESS | any }\n");
@@ -85,6 +86,7 @@
 	__u16 encapflags = 0;
 	__u16 encapsport = 0;
 	__u16 encapdport = 0;
+	__u8 metadata = 0;
 
 	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
 		if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 0) {
@@ -161,6 +163,8 @@
 		if (iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIXLEN])
 			ip6rdrelayprefixlen =
 				rta_getattr_u16(iptuninfo[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
+		if (iptuninfo[IFLA_IPTUN_COLLECT_METADATA])
+			metadata = 1;
 	}
 
 	while (argc > 0) {
@@ -257,6 +261,8 @@
 			encapflags |= TUNNEL_ENCAP_FLAG_REMCSUM;
 		} else if (strcmp(*argv, "noencap-remcsum") == 0) {
 			encapflags &= ~TUNNEL_ENCAP_FLAG_REMCSUM;
+		} else if (strcmp(*argv, "external") == 0) {
+			metadata = 1;
 		} else if (strcmp(*argv, "6rd-prefix") == 0) {
 			inet_prefix prefix;
 
@@ -291,6 +297,11 @@
 		exit(-1);
 	}
 
+	if (metadata) {
+		addattr_l(n, 1024, IFLA_IPTUN_COLLECT_METADATA, NULL, 0);
+		return 0;
+	}
+
 	addattr32(n, 1024, IFLA_IPTUN_LINK, link);
 	addattr32(n, 1024, IFLA_IPTUN_LOCAL, laddr);
 	addattr32(n, 1024, IFLA_IPTUN_REMOTE, raddr);