net/sched: act_tunnel_key: Allow key-less tunnels

Allow setting a tunnel without a tunnel key. This is required for
tunneling protocols, such as GRE, that define the key as an optional
field.
Signed-off-by: Adi Nissim <adin@mellanox.com>
Acked-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_tunnel_key.c

@@ -210,9 +210,9 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	struct tcf_tunnel_key *t;
 	bool exists = false;
 	__be16 dst_port = 0;
+	__be64 key_id = 0;
 	int opts_len = 0;
-	__be64 key_id;
-	__be16 flags;
+	__be16 flags = 0;
 	u8 tos, ttl;
 	int ret = 0;
 	int err;
@@ -246,15 +246,15 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 	case TCA_TUNNEL_KEY_ACT_RELEASE:
 		break;
 	case TCA_TUNNEL_KEY_ACT_SET:
-		if (!tb[TCA_TUNNEL_KEY_ENC_KEY_ID]) {
-			NL_SET_ERR_MSG(extack, "Missing tunnel key id");
-			ret = -EINVAL;
-			goto err_out;
-		}
+		if (tb[TCA_TUNNEL_KEY_ENC_KEY_ID]) {
+			__be32 key32;
 
-		key_id = key32_to_tunnel_id(nla_get_be32(tb[TCA_TUNNEL_KEY_ENC_KEY_ID]));
+			key32 = nla_get_be32(tb[TCA_TUNNEL_KEY_ENC_KEY_ID]);
+			key_id = key32_to_tunnel_id(key32);
+			flags = TUNNEL_KEY;
+		}
 
-		flags = TUNNEL_KEY | TUNNEL_CSUM;
+		flags |= TUNNEL_CSUM;
 		if (tb[TCA_TUNNEL_KEY_NO_CSUM] &&
 		    nla_get_u8(tb[TCA_TUNNEL_KEY_NO_CSUM]))
 			flags &= ~TUNNEL_CSUM;
@@ -508,7 +508,8 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a,
 		struct ip_tunnel_key *key = &info->key;
 		__be32 key_id = tunnel_id_to_key32(key->tun_id);
 
-		if (nla_put_be32(skb, TCA_TUNNEL_KEY_ENC_KEY_ID, key_id) ||
+		if (((key->tun_flags & TUNNEL_KEY) &&
+		     nla_put_be32(skb, TCA_TUNNEL_KEY_ENC_KEY_ID, key_id)) ||
 		    tunnel_key_dump_addresses(skb,
 					      &params->tcft_enc_metadata->u.tun_info) ||
 		    nla_put_be16(skb, TCA_TUNNEL_KEY_ENC_DST_PORT, key->tp_dst) ||