netfilter: conntrack: add support for DCCP handshake sequence to ctnetlink

This patch adds CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ that exposes
the u64 handshake sequence number to user-space.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NPatrick McHardy <kaber@trash.net>

include/linux/netfilter/nfnetlink_conntrack.h

@@ -101,6 +101,7 @@ enum ctattr_protoinfo_dccp {
 	CTA_PROTOINFO_DCCP_UNSPEC,
 	CTA_PROTOINFO_DCCP_STATE,
 	CTA_PROTOINFO_DCCP_ROLE,
+	CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
 	__CTA_PROTOINFO_DCCP_MAX,
 };
 #define CTA_PROTOINFO_DCCP_MAX (__CTA_PROTOINFO_DCCP_MAX - 1)

include/net/netlink.h

@@ -939,6 +939,15 @@ static inline u64 nla_get_u64(const struct nlattr *nla)
 	return tmp;
 }
 
+/**
+ * nla_get_be64 - return payload of __be64 attribute
+ * @nla: __be64 netlink attribute
+ */
+static inline __be64 nla_get_be64(const struct nlattr *nla)
+{
+	return *(__be64 *) nla_data(nla);
+}
+
 /**
  * nla_get_flag - return payload of flag attribute
  * @nla: flag netlink attribute

net/netfilter/nf_conntrack_proto_dccp.c

@@ -635,6 +635,8 @@ static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 	NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state);
 	NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE,
 		   ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]);
+	NLA_PUT_BE64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
+		     cpu_to_be64(ct->proto.dccp.handshake_seq));
 	nla_nest_end(skb, nest_parms);
 	read_unlock_bh(&dccp_lock);
 	return 0;
@@ -647,6 +649,7 @@ static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
 static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
 	[CTA_PROTOINFO_DCCP_STATE]	= { .type = NLA_U8 },
 	[CTA_PROTOINFO_DCCP_ROLE]	= { .type = NLA_U8 },
+	[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 },
 };
 
 static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
@@ -679,6 +682,10 @@ static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
 		ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
 		ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
 	}
+	if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) {
+		ct->proto.dccp.handshake_seq =
+		be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]));
+	}
 	write_unlock_bh(&dccp_lock);
 	return 0;
 }