[NETFILTER]: nf_conntrack: add DCCP protocol support

Add DCCP conntrack helper. Thanks to Gerrit Renker <gerrit@erg.abdn.ac.uk>
for review and testing.
Signed-off-by: Patrick McHardy <kaber@trash.net>

include/linux/netfilter/nf_conntrack_dccp.h

+#ifndef _NF_CONNTRACK_DCCP_H
+#define _NF_CONNTRACK_DCCP_H
+
+/* Exposed to userspace over nfnetlink */
+enum ct_dccp_states {
+	CT_DCCP_NONE,
+	CT_DCCP_REQUEST,
+	CT_DCCP_RESPOND,
+	CT_DCCP_PARTOPEN,
+	CT_DCCP_OPEN,
+	CT_DCCP_CLOSEREQ,
+	CT_DCCP_CLOSING,
+	CT_DCCP_TIMEWAIT,
+	CT_DCCP_IGNORE,
+	CT_DCCP_INVALID,
+	__CT_DCCP_MAX
+};
+#define CT_DCCP_MAX		(__CT_DCCP_MAX - 1)
+
+enum ct_dccp_roles {
+	CT_DCCP_ROLE_CLIENT,
+	CT_DCCP_ROLE_SERVER,
+	__CT_DCCP_ROLE_MAX
+};
+#define CT_DCCP_ROLE_MAX	(__CT_DCCP_ROLE_MAX - 1)
+
+#ifdef __KERNEL__
+#include <net/netfilter/nf_conntrack_tuple.h>
+
+struct nf_ct_dccp {
+	u_int8_t	role[IP_CT_DIR_MAX];
+	u_int8_t	state;
+	u_int8_t	last_pkt;
+	u_int8_t	last_dir;
+	u_int64_t	handshake_seq;
+};
+
+#endif /* __KERNEL__ */
+
+#endif /* _NF_CONNTRACK_DCCP_H */

include/linux/netfilter/nfnetlink_conntrack.h

@@ -80,6 +80,7 @@ enum ctattr_l4proto {
 enum ctattr_protoinfo {
 	CTA_PROTOINFO_UNSPEC,
 	CTA_PROTOINFO_TCP,
+	CTA_PROTOINFO_DCCP,
 	__CTA_PROTOINFO_MAX
 };
 #define CTA_PROTOINFO_MAX (__CTA_PROTOINFO_MAX - 1)
@@ -95,6 +96,13 @@ enum ctattr_protoinfo_tcp {
 };
 #define CTA_PROTOINFO_TCP_MAX (__CTA_PROTOINFO_TCP_MAX - 1)
 
+enum ctattr_protoinfo_dccp {
+	CTA_PROTOINFO_DCCP_UNSPEC,
+	CTA_PROTOINFO_DCCP_STATE,
+	__CTA_PROTOINFO_DCCP_MAX,
+};
+#define CTA_PROTOINFO_DCCP_MAX (__CTA_PROTOINFO_DCCP_MAX - 1)
+
 enum ctattr_counters {
 	CTA_COUNTERS_UNSPEC,
 	CTA_COUNTERS_PACKETS,		/* old 64bit counters */

include/net/netfilter/nf_conntrack.h

@@ -20,6 +20,7 @@
 #include <asm/atomic.h>
 
 #include <linux/netfilter/nf_conntrack_tcp.h>
+#include <linux/netfilter/nf_conntrack_dccp.h>
 #include <linux/netfilter/nf_conntrack_sctp.h>
 #include <linux/netfilter/nf_conntrack_proto_gre.h>
 #include <net/netfilter/ipv4/nf_conntrack_icmp.h>
@@ -30,6 +31,7 @@
 /* per conntrack: protocol private data */
 union nf_conntrack_proto {
 	/* insert conntrack proto private data here */
+	struct nf_ct_dccp dccp;
 	struct ip_ct_sctp sctp;
 	struct ip_ct_tcp tcp;
 	struct ip_ct_icmp icmp;

include/net/netfilter/nf_conntrack_tuple.h

@@ -39,6 +39,9 @@ union nf_conntrack_man_proto
 	struct {
 		__be16 id;
 	} icmp;
+	struct {
+		__be16 port;
+	} dccp;
 	struct {
 		__be16 port;
 	} sctp;
@@ -77,6 +80,9 @@ struct nf_conntrack_tuple
 			struct {
 				u_int8_t type, code;
 			} icmp;
+			struct {
+				__be16 port;
+			} dccp;
 			struct {
 				__be16 port;
 			} sctp;

net/netfilter/Kconfig

@@ -86,6 +86,16 @@ config NF_CONNTRACK_EVENTS
 
 	  If unsure, say `N'.
 
+config NF_CT_PROTO_DCCP
+	tristate 'DCCP protocol connection tracking support (EXPERIMENTAL)'
+	depends on EXPERIMENTAL && NF_CONNTRACK
+	depends on NETFILTER_ADVANCED
+	help
+	  With this option enabled, the layer 3 independent connection
+	  tracking code will be able to do state tracking on DCCP connections.
+
+	  If unsure, say 'N'.
+
 config NF_CT_PROTO_GRE
 	tristate
 	depends on NF_CONNTRACK

net/netfilter/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_NETFILTER_NETLINK_LOG) += nfnetlink_log.o
 obj-$(CONFIG_NF_CONNTRACK) += nf_conntrack.o
 
 # SCTP protocol connection tracking
+obj-$(CONFIG_NF_CT_PROTO_DCCP) += nf_conntrack_proto_dccp.o
 obj-$(CONFIG_NF_CT_PROTO_GRE) += nf_conntrack_proto_gre.o
 obj-$(CONFIG_NF_CT_PROTO_SCTP) += nf_conntrack_proto_sctp.o
 obj-$(CONFIG_NF_CT_PROTO_UDPLITE) += nf_conntrack_proto_udplite.o