[NETFILTER]: Add ctnetlink subsystem

Add ctnetlink subsystem for userspace-access to ip_conntrack table.
This allows reading and updating of existing entries, as well as
creating new ones (and new expect's) via nfnetlink.

Please note the 'strange' byte order: nfattr (tag+length) are in host
byte order, while the payload is always guaranteed to be in network
byte order.  This allows a simple userspace process to encapsulate netlink
messages into arch-independent udp packets by just processing/swapping the
headers and not knowing anything about the actual payload.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/nfnetlink.h

@@ -56,7 +56,7 @@ struct nfgenmsg {
 	u_int16_t res_id;		/* resource id */
 } __attribute__ ((packed));
 
-#define NFNETLINK_V1	1
+#define NFNETLINK_V0	0
 
 #define NFM_NFA(n)      ((struct nfattr *)(((char *)(n)) \
         + NLMSG_ALIGN(sizeof(struct nfgenmsg))))
@@ -81,6 +81,7 @@ enum nfnl_subsys_id {
 
 #ifdef __KERNEL__
 
+#include <linux/netlink.h>
 #include <linux/capability.h>
 
 struct nfnl_callback

include/linux/netfilter/nfnetlink_conntrack.h

@@ -0,0 +1,123 @@
+#ifndef _IPCONNTRACK_NETLINK_H
+#define _IPCONNTRACK_NETLINK_H
+#include <linux/netfilter/nfnetlink.h>
+
+enum cntl_msg_types {
+	IPCTNL_MSG_CT_NEW,
+	IPCTNL_MSG_CT_GET,
+	IPCTNL_MSG_CT_DELETE,
+	IPCTNL_MSG_CT_GET_CTRZERO,
+
+	IPCTNL_MSG_MAX
+};
+
+enum ctnl_exp_msg_types {
+	IPCTNL_MSG_EXP_NEW,
+	IPCTNL_MSG_EXP_GET,
+	IPCTNL_MSG_EXP_DELETE,
+
+	IPCTNL_MSG_EXP_MAX
+};
+
+
+enum ctattr_type {
+	CTA_UNSPEC,
+	CTA_TUPLE_ORIG,
+	CTA_TUPLE_REPLY,
+	CTA_STATUS,
+	CTA_PROTOINFO,
+	CTA_HELP,
+	CTA_NAT,
+	CTA_TIMEOUT,
+	CTA_MARK,
+	CTA_COUNTERS_ORIG,
+	CTA_COUNTERS_REPLY,
+	CTA_USE,
+	CTA_EXPECT,
+	CTA_ID,
+	__CTA_MAX
+};
+#define CTA_MAX (__CTA_MAX - 1)
+
+enum ctattr_tuple {
+	CTA_TUPLE_UNSPEC,
+	CTA_TUPLE_IP,
+	CTA_TUPLE_PROTO,
+	__CTA_TUPLE_MAX
+};
+#define CTA_TUPLE_MAX (__CTA_TUPLE_MAX - 1)
+
+enum ctattr_ip {
+	CTA_IP_UNSPEC,
+	CTA_IP_V4_SRC,
+	CTA_IP_V4_DST,
+	CTA_IP_V6_SRC,
+	CTA_IP_V6_DST,
+	__CTA_IP_MAX
+};
+#define CTA_IP_MAX (__CTA_IP_MAX - 1)
+
+enum ctattr_l4proto {
+	CTA_PROTO_UNSPEC,
+	CTA_PROTO_NUM,
+	CTA_PROTO_SRC_PORT,
+	CTA_PROTO_DST_PORT,
+	CTA_PROTO_ICMP_ID,
+	CTA_PROTO_ICMP_TYPE,
+	CTA_PROTO_ICMP_CODE,
+	__CTA_PROTO_MAX
+};
+#define CTA_PROTO_MAX (__CTA_PROTO_MAX - 1)
+
+enum ctattr_protoinfo {
+	CTA_PROTOINFO_UNSPEC,
+	CTA_PROTOINFO_TCP_STATE,
+	__CTA_PROTOINFO_MAX
+};
+#define CTA_PROTOINFO_MAX (__CTA_PROTOINFO_MAX - 1)
+
+enum ctattr_counters {
+	CTA_COUNTERS_UNSPEC,
+	CTA_COUNTERS_PACKETS,
+	CTA_COUNTERS_BYTES,
+	__CTA_COUNTERS_MAX
+};
+#define CTA_COUNTERS_MAX (__CTA_COUNTERS_MAX - 1)
+
+enum ctattr_nat {
+	CTA_NAT_UNSPEC,
+	CTA_NAT_MINIP,
+	CTA_NAT_MAXIP,
+	CTA_NAT_PROTO,
+	__CTA_NAT_MAX
+};
+#define CTA_NAT_MAX (__CTA_NAT_MAX - 1)
+
+enum ctattr_protonat {
+	CTA_PROTONAT_UNSPEC,
+	CTA_PROTONAT_PORT_MIN,
+	CTA_PROTONAT_PORT_MAX,
+	__CTA_PROTONAT_MAX
+};
+#define CTA_PROTONAT_MAX (__CTA_PROTONAT_MAX - 1)
+
+enum ctattr_expect {
+	CTA_EXPECT_UNSPEC,
+	CTA_EXPECT_TUPLE,
+	CTA_EXPECT_MASK,
+	CTA_EXPECT_TIMEOUT,
+	CTA_EXPECT_ID,
+	__CTA_EXPECT_MAX
+};
+#define CTA_EXPECT_MAX (__CTA_EXPECT_MAX - 1)
+
+enum ctattr_help {
+	CTA_HELP_UNSPEC,
+	CTA_HELP_NAME,
+	__CTA_HELP_MAX
+};
+#define CTA_HELP_MAX (__CTA_HELP_MAX - 1)
+
+#define CTA_HELP_MAXNAMESIZE	32
+
+#endif /* _IPCONNTRACK_NETLINK_H */