net: vxlan: Add extack support to vxlan_fdb_delete

This patch adds extack msg support to vxlan_fdb_delete and vxlan_fdb_parse.
extack is used to propagate meaningful error msgs to the user of vxlan
fdb netlink api

Signed-off-by: Alaa Mohamed <eng.alaamohamedsoliman.am@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan/vxlan_core.c

@@ -1129,19 +1129,25 @@ static void vxlan_fdb_dst_destroy(struct vxlan_dev *vxlan, struct vxlan_fdb *f,
 
 static int vxlan_fdb_parse(struct nlattr *tb[], struct vxlan_dev *vxlan,
 			   union vxlan_addr *ip, __be16 *port, __be32 *src_vni,
-			   __be32 *vni, u32 *ifindex, u32 *nhid)
+			   __be32 *vni, u32 *ifindex, u32 *nhid,
+			   struct netlink_ext_ack *extack)
 {
 	struct net *net = dev_net(vxlan->dev);
 	int err;
 
 	if (tb[NDA_NH_ID] && (tb[NDA_DST] || tb[NDA_VNI] || tb[NDA_IFINDEX] ||
-	    tb[NDA_PORT]))
-		return -EINVAL;
+	    tb[NDA_PORT])) {
+			NL_SET_ERR_MSG(extack,
+						  "DST, VNI, ifindex and port are mutually exclusive with NH_ID");
+			return -EINVAL;
+		}
 
 	if (tb[NDA_DST]) {
 		err = vxlan_nla_get_addr(ip, tb[NDA_DST]);
-		if (err)
+		if (err) {
+			NL_SET_ERR_MSG(extack, "Unsupported address family");
 			return err;
+		}
 	} else {
 		union vxlan_addr *remote = &vxlan->default_dst.remote_ip;
 
@@ -1157,24 +1163,30 @@ static int vxlan_fdb_parse(struct nlattr *tb[], struct vxlan_dev *vxlan,
 	}
 
 	if (tb[NDA_PORT]) {
-		if (nla_len(tb[NDA_PORT]) != sizeof(__be16))
+		if (nla_len(tb[NDA_PORT]) != sizeof(__be16)) {
+			NL_SET_ERR_MSG(extack, "Invalid vxlan port");
 			return -EINVAL;
+		}
 		*port = nla_get_be16(tb[NDA_PORT]);
 	} else {
 		*port = vxlan->cfg.dst_port;
 	}
 
 	if (tb[NDA_VNI]) {
-		if (nla_len(tb[NDA_VNI]) != sizeof(u32))
+		if (nla_len(tb[NDA_VNI]) != sizeof(u32)) {
+			NL_SET_ERR_MSG(extack, "Invalid vni");
 			return -EINVAL;
+		}
 		*vni = cpu_to_be32(nla_get_u32(tb[NDA_VNI]));
 	} else {
 		*vni = vxlan->default_dst.remote_vni;
 	}
 
 	if (tb[NDA_SRC_VNI]) {
-		if (nla_len(tb[NDA_SRC_VNI]) != sizeof(u32))
+		if (nla_len(tb[NDA_SRC_VNI]) != sizeof(u32)) {
+			NL_SET_ERR_MSG(extack, "Invalid src vni");
 			return -EINVAL;
+		}
 		*src_vni = cpu_to_be32(nla_get_u32(tb[NDA_SRC_VNI]));
 	} else {
 		*src_vni = vxlan->default_dst.remote_vni;
@@ -1183,12 +1195,16 @@ static int vxlan_fdb_parse(struct nlattr *tb[], struct vxlan_dev *vxlan,
 	if (tb[NDA_IFINDEX]) {
 		struct net_device *tdev;
 
-		if (nla_len(tb[NDA_IFINDEX]) != sizeof(u32))
+		if (nla_len(tb[NDA_IFINDEX]) != sizeof(u32)) {
+			NL_SET_ERR_MSG(extack, "Invalid ifindex");
 			return -EINVAL;
+		}
 		*ifindex = nla_get_u32(tb[NDA_IFINDEX]);
 		tdev = __dev_get_by_index(net, *ifindex);
-		if (!tdev)
+		if (!tdev) {
+			NL_SET_ERR_MSG(extack, "Device not found");
 			return -EADDRNOTAVAIL;
+		}
 	} else {
 		*ifindex = 0;
 	}
@@ -1226,7 +1242,7 @@ static int vxlan_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 		return -EINVAL;
 
 	err = vxlan_fdb_parse(tb, vxlan, &ip, &port, &src_vni, &vni, &ifindex,
-			      &nhid);
+			      &nhid, extack);
 	if (err)
 		return err;
 
@@ -1292,7 +1308,7 @@ static int vxlan_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
 	int err;
 
 	err = vxlan_fdb_parse(tb, vxlan, &ip, &port, &src_vni, &vni, &ifindex,
-			      &nhid);
+			      &nhid, extack);
 	if (err)
 		return err;