[NETFILTER] ctnetlink: add support to change protocol info

This patch add support to change the state of the private protocol
information via conntrack_netlink.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/netfilter/ip_conntrack_netlink.c

@@ -949,6 +949,31 @@ ctnetlink_change_timeout(struct ip_conntrack *ct, struct nfattr *cda[])
 	return 0;
 }
 
+static inline int
+ctnetlink_change_protoinfo(struct ip_conntrack *ct, struct nfattr *cda[])
+{
+	struct nfattr *tb[CTA_PROTOINFO_MAX], *attr = cda[CTA_PROTOINFO-1];
+	struct ip_conntrack_protocol *proto;
+	u_int16_t npt = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum;
+	int err = 0;
+
+	if (nfattr_parse_nested(tb, CTA_PROTOINFO_MAX, attr) < 0)
+		goto nfattr_failure;
+
+	proto = ip_conntrack_proto_find_get(npt);
+	if (!proto)
+		return -EINVAL;
+
+	if (proto->from_nfattr)
+		err = proto->from_nfattr(tb, ct);
+	ip_conntrack_proto_put(proto); 
+
+	return err;
+
+nfattr_failure:
+	return -ENOMEM;
+}
+
 static int
 ctnetlink_change_conntrack(struct ip_conntrack *ct, struct nfattr *cda[])
 {
@@ -974,6 +999,12 @@ ctnetlink_change_conntrack(struct ip_conntrack *ct, struct nfattr *cda[])
 			return err;
 	}
 
+	if (cda[CTA_PROTOINFO-1]) {
+		err = ctnetlink_change_protoinfo(ct, cda);
+		if (err < 0)
+			return err;
+	}
+
 	DEBUGP("all done\n");
 	return 0;
 }
@@ -1003,6 +1034,12 @@ ctnetlink_create_conntrack(struct nfattr *cda[],
 	if (err < 0)
 		goto err;
 
+	if (cda[CTA_PROTOINFO-1]) {
+		err = ctnetlink_change_protoinfo(ct, cda);
+		if (err < 0)
+			return err;
+	}
+
 	ct->helper = ip_conntrack_helper_find_get(rtuple);
 
 	add_timer(&ct->timeout);