[NETFILTER]: Add ctnetlink port for nf_conntrack

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netfilter/nfnetlink_conntrack.h

@@ -64,6 +64,9 @@ enum ctattr_l4proto {
 	CTA_PROTO_ICMP_ID,
 	CTA_PROTO_ICMP_TYPE,
 	CTA_PROTO_ICMP_CODE,
+	CTA_PROTO_ICMPV6_ID,
+	CTA_PROTO_ICMPV6_TYPE,
+	CTA_PROTO_ICMPV6_CODE,
 	__CTA_PROTO_MAX
 };
 #define CTA_PROTO_MAX (__CTA_PROTO_MAX - 1)

include/net/netfilter/nf_conntrack.h

@@ -94,6 +94,9 @@ struct nf_conn
 	/* Current number of expected connections */
 	unsigned int expecting;
 
+	/* Unique ID that identifies this conntrack*/
+	unsigned int id;
+
 	/* Helper. if any */
 	struct nf_conntrack_helper *helper;
 
@@ -140,6 +143,9 @@ struct nf_conntrack_expect
 	/* Usage count. */
 	atomic_t use;
 
+	/* Unique ID */
+	unsigned int id;
+
 	/* Flags */
 	unsigned int flags;
 
@@ -190,6 +196,31 @@ static inline void nf_ct_put(struct nf_conn *ct)
 	nf_conntrack_put(&ct->ct_general);
 }
 
+extern struct nf_conntrack_tuple_hash *
+__nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
+		    const struct nf_conn *ignored_conntrack);
+
+extern void nf_conntrack_hash_insert(struct nf_conn *ct);
+
+extern struct nf_conntrack_expect *
+__nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple);
+
+extern struct nf_conntrack_expect *
+nf_conntrack_expect_find(const struct nf_conntrack_tuple *tuple);
+
+extern void nf_ct_unlink_expect(struct nf_conntrack_expect *exp);
+
+extern void nf_ct_remove_expectations(struct nf_conn *ct);
+
+extern void nf_conntrack_flush(void);
+
+extern struct nf_conntrack_helper *
+nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple);
+extern void nf_ct_helper_put(struct nf_conntrack_helper *helper);
+
+extern struct nf_conntrack_helper *
+__nf_conntrack_helper_find_byname(const char *name);
+
 /* call to create an explicit dependency on nf_conntrack. */
 extern void need_nf_conntrack(void);
 

include/net/netfilter/nf_conntrack_helper.h

@@ -33,6 +33,8 @@ struct nf_conntrack_helper
 		    unsigned int protoff,
 		    struct nf_conn *ct,
 		    enum ip_conntrack_info conntrackinfo);
+
+	int (*to_nfattr)(struct sk_buff *skb, const struct nf_conn *ct);
 };
 
 extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);

include/net/netfilter/nf_conntrack_l3proto.h

@@ -14,6 +14,8 @@
 #include <linux/seq_file.h>
 #include <net/netfilter/nf_conntrack.h>
 
+struct nfattr;
+
 struct nf_conntrack_l3proto
 {
 	/* Next pointer. */
@@ -70,6 +72,12 @@ struct nf_conntrack_l3proto
 
 	u_int32_t (*get_features)(const struct nf_conntrack_tuple *tuple);
 
+	int (*tuple_to_nfattr)(struct sk_buff *skb,
+			       const struct nf_conntrack_tuple *t);
+
+	int (*nfattr_to_tuple)(struct nfattr *tb[],
+			       struct nf_conntrack_tuple *t);
+
 	/* Module (if any) which this is connected to. */
 	struct module *me;
 };
@@ -81,11 +89,16 @@ extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
 extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
 
 static inline struct nf_conntrack_l3proto *
-nf_ct_find_l3proto(u_int16_t l3proto)
+__nf_ct_l3proto_find(u_int16_t l3proto)
 {
 	return nf_ct_l3protos[l3proto];
 }
 
+extern struct nf_conntrack_l3proto *
+nf_ct_l3proto_find_get(u_int16_t l3proto);
+
+extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
+
 /* Existing built-in protocols */
 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4;
 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6;

include/net/netfilter/nf_conntrack_protocol.h

@@ -12,6 +12,7 @@
 #include <net/netfilter/nf_conntrack.h>
 
 struct seq_file;
+struct nfattr;
 
 struct nf_conntrack_protocol
 {
@@ -66,6 +67,18 @@ struct nf_conntrack_protocol
 		     enum ip_conntrack_info *ctinfo,
 		     int pf, unsigned int hooknum);
 
+	/* convert protoinfo to nfnetink attributes */
+	int (*to_nfattr)(struct sk_buff *skb, struct nfattr *nfa,
+			 const struct nf_conn *ct);
+
+	/* convert nfnetlink attributes to protoinfo */
+	int (*from_nfattr)(struct nfattr *tb[], struct nf_conn *ct);
+
+	int (*tuple_to_nfattr)(struct sk_buff *skb,
+			       const struct nf_conntrack_tuple *t);
+	int (*nfattr_to_tuple)(struct nfattr *tb[],
+			       struct nf_conntrack_tuple *t);
+
 	/* Module (if any) which this is connected to. */
 	struct module *me;
 };
@@ -80,12 +93,23 @@ extern struct nf_conntrack_protocol nf_conntrack_generic_protocol;
 extern struct nf_conntrack_protocol **nf_ct_protos[PF_MAX];
 
 extern struct nf_conntrack_protocol *
-nf_ct_find_proto(u_int16_t l3proto, u_int8_t protocol);
+__nf_ct_proto_find(u_int16_t l3proto, u_int8_t protocol);
+
+extern struct nf_conntrack_protocol *
+nf_ct_proto_find_get(u_int16_t l3proto, u_int8_t protocol);
+
+extern void nf_ct_proto_put(struct nf_conntrack_protocol *p);
 
 /* Protocol registration. */
 extern int nf_conntrack_protocol_register(struct nf_conntrack_protocol *proto);
 extern void nf_conntrack_protocol_unregister(struct nf_conntrack_protocol *proto);
 
+/* Generic netlink helpers */
+extern int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
+				      const struct nf_conntrack_tuple *tuple);
+extern int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
+				      struct nf_conntrack_tuple *t);
+
 /* Log invalid packets */
 extern unsigned int nf_ct_log_invalid;
 

net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c

@@ -392,6 +392,48 @@ getorigdst(struct sock *sk, int optval, void __user *user, int *len)
 	return -ENOENT;
 }
 
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
+				const struct nf_conntrack_tuple *tuple)
+{
+	NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
+		&tuple->src.u3.ip);
+	NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
+		&tuple->dst.u3.ip);
+	return 0;
+
+nfattr_failure:
+	return -1;
+}
+
+static const size_t cta_min_ip[CTA_IP_MAX] = {
+	[CTA_IP_V4_SRC-1]       = sizeof(u_int32_t),
+	[CTA_IP_V4_DST-1]       = sizeof(u_int32_t),
+};
+
+static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
+				struct nf_conntrack_tuple *t)
+{
+	if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
+		return -EINVAL;
+
+	if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
+		return -EINVAL;
+
+	t->src.u3.ip =
+		*(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
+	t->dst.u3.ip =
+		*(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_DST-1]);
+
+	return 0;
+}
+#endif
+
 static struct nf_sockopt_ops so_getorigdst = {
 	.pf		= PF_INET,
 	.get_optmin	= SO_ORIGINAL_DST,
@@ -408,6 +450,11 @@ struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
 	.print_conntrack = ipv4_print_conntrack,
 	.prepare	 = ipv4_prepare,
 	.get_features	 = ipv4_get_features,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.tuple_to_nfattr = ipv4_tuple_to_nfattr,
+	.nfattr_to_tuple = ipv4_nfattr_to_tuple,
+#endif
 	.me		 = THIS_MODULE,
 };
 

net/ipv4/netfilter/nf_conntrack_proto_icmp.c

@@ -50,20 +50,21 @@ static int icmp_pkt_to_tuple(const struct sk_buff *skb,
 	return 1;
 }
 
-static int icmp_invert_tuple(struct nf_conntrack_tuple *tuple,
-			     const struct nf_conntrack_tuple *orig)
-{
-	/* Add 1; spaces filled with 0. */
-	static u_int8_t invmap[]
-		= { [ICMP_ECHO] = ICMP_ECHOREPLY + 1,
+/* Add 1; spaces filled with 0. */
+static const u_int8_t invmap[] = {
+	[ICMP_ECHO] = ICMP_ECHOREPLY + 1,
 	[ICMP_ECHOREPLY] = ICMP_ECHO + 1,
 	[ICMP_TIMESTAMP] = ICMP_TIMESTAMPREPLY + 1,
 	[ICMP_TIMESTAMPREPLY] = ICMP_TIMESTAMP + 1,
 	[ICMP_INFO_REQUEST] = ICMP_INFO_REPLY + 1,
 	[ICMP_INFO_REPLY] = ICMP_INFO_REQUEST + 1,
 	[ICMP_ADDRESS] = ICMP_ADDRESSREPLY + 1,
-		    [ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1};
+	[ICMP_ADDRESSREPLY] = ICMP_ADDRESS + 1
+};
 
+static int icmp_invert_tuple(struct nf_conntrack_tuple *tuple,
+			     const struct nf_conntrack_tuple *orig)
+{
 	if (orig->dst.u.icmp.type >= sizeof(invmap)
 	    || !invmap[orig->dst.u.icmp.type])
 		return 0;
@@ -120,11 +121,12 @@ static int icmp_packet(struct nf_conn *ct,
 static int icmp_new(struct nf_conn *conntrack,
 		    const struct sk_buff *skb, unsigned int dataoff)
 {
-	static u_int8_t valid_new[]
-		= { [ICMP_ECHO] = 1,
+	static const u_int8_t valid_new[] = {
+		[ICMP_ECHO] = 1,
 		[ICMP_TIMESTAMP] = 1,
 		[ICMP_INFO_REQUEST] = 1,
-		    [ICMP_ADDRESS] = 1 };
+		[ICMP_ADDRESS] = 1
+	};
 
 	if (conntrack->tuplehash[0].tuple.dst.u.icmp.type >= sizeof(valid_new)
 	    || !valid_new[conntrack->tuplehash[0].tuple.dst.u.icmp.type]) {
@@ -168,7 +170,7 @@ icmp_error_message(struct sk_buff *skb,
 		return -NF_ACCEPT;
 	}
 
-	innerproto = nf_ct_find_proto(PF_INET, inside->ip.protocol);
+	innerproto = __nf_ct_proto_find(PF_INET, inside->ip.protocol);
 	dataoff = skb->nh.iph->ihl*4 + sizeof(inside->icmp);
 	/* Are they talking about one of our connections? */
 	if (!nf_ct_get_tuple(skb, dataoff, dataoff + inside->ip.ihl*4, PF_INET,
@@ -281,6 +283,60 @@ icmp_error(struct sk_buff *skb, unsigned int dataoff,
 	return icmp_error_message(skb, ctinfo, hooknum);
 }
 
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static int icmp_tuple_to_nfattr(struct sk_buff *skb,
+				const struct nf_conntrack_tuple *t)
+{
+	NFA_PUT(skb, CTA_PROTO_ICMP_ID, sizeof(u_int16_t),
+		&t->src.u.icmp.id);
+	NFA_PUT(skb, CTA_PROTO_ICMP_TYPE, sizeof(u_int8_t),
+		&t->dst.u.icmp.type);
+	NFA_PUT(skb, CTA_PROTO_ICMP_CODE, sizeof(u_int8_t),
+		&t->dst.u.icmp.code);
+
+	return 0;
+
+nfattr_failure:
+	return -1;
+}
+
+static const size_t cta_min_proto[CTA_PROTO_MAX] = {
+	[CTA_PROTO_ICMP_TYPE-1] = sizeof(u_int8_t),
+	[CTA_PROTO_ICMP_CODE-1] = sizeof(u_int8_t),
+	[CTA_PROTO_ICMP_ID-1]   = sizeof(u_int16_t)
+};
+
+static int icmp_nfattr_to_tuple(struct nfattr *tb[],
+				struct nf_conntrack_tuple *tuple)
+{
+	if (!tb[CTA_PROTO_ICMP_TYPE-1]
+	    || !tb[CTA_PROTO_ICMP_CODE-1]
+	    || !tb[CTA_PROTO_ICMP_ID-1])
+		return -EINVAL;
+
+	if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
+		return -EINVAL;
+
+	tuple->dst.u.icmp.type = 
+			*(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMP_TYPE-1]);
+	tuple->dst.u.icmp.code =
+			*(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMP_CODE-1]);
+	tuple->src.u.icmp.id =
+			*(u_int16_t *)NFA_DATA(tb[CTA_PROTO_ICMP_ID-1]);
+
+	if (tuple->dst.u.icmp.type >= sizeof(invmap)
+	    || !invmap[tuple->dst.u.icmp.type])
+		return -EINVAL;
+
+	return 0;
+}
+#endif
+
 struct nf_conntrack_protocol nf_conntrack_protocol_icmp =
 {
 	.list			= { NULL, NULL },
@@ -295,7 +351,12 @@ struct nf_conntrack_protocol nf_conntrack_protocol_icmp =
 	.new			= icmp_new,
 	.error			= icmp_error,
 	.destroy		= NULL,
-	.me			= NULL
+	.me			= NULL,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.tuple_to_nfattr	= icmp_tuple_to_nfattr,
+	.nfattr_to_tuple	= icmp_nfattr_to_tuple,
+#endif
 };
 
 EXPORT_SYMBOL(nf_conntrack_protocol_icmp);

net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c

@@ -401,6 +401,48 @@ static ctl_table nf_ct_net_table[] = {
 };
 #endif
 
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static int ipv6_tuple_to_nfattr(struct sk_buff *skb,
+				const struct nf_conntrack_tuple *tuple)
+{
+	NFA_PUT(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4,
+		&tuple->src.u3.ip6);
+	NFA_PUT(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4,
+		&tuple->dst.u3.ip6);
+	return 0;
+
+nfattr_failure:
+	return -1;
+}
+
+static const size_t cta_min_ip[CTA_IP_MAX] = {
+	[CTA_IP_V6_SRC-1]       = sizeof(u_int32_t)*4,
+	[CTA_IP_V6_DST-1]       = sizeof(u_int32_t)*4,
+};
+
+static int ipv6_nfattr_to_tuple(struct nfattr *tb[],
+				struct nf_conntrack_tuple *t)
+{
+	if (!tb[CTA_IP_V6_SRC-1] || !tb[CTA_IP_V6_DST-1])
+		return -EINVAL;
+
+	if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
+		return -EINVAL;
+
+	memcpy(&t->src.u3.ip6, NFA_DATA(tb[CTA_IP_V6_SRC-1]), 
+	       sizeof(u_int32_t) * 4);
+	memcpy(&t->dst.u3.ip6, NFA_DATA(tb[CTA_IP_V6_DST-1]),
+	       sizeof(u_int32_t) * 4);
+
+	return 0;
+}
+#endif
+
 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 = {
 	.l3proto		= PF_INET6,
 	.name			= "ipv6",
@@ -409,6 +451,11 @@ struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 = {
 	.print_tuple		= ipv6_print_tuple,
 	.print_conntrack	= ipv6_print_conntrack,
 	.prepare		= ipv6_prepare,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.tuple_to_nfattr	= ipv6_tuple_to_nfattr,
+	.nfattr_to_tuple	= ipv6_nfattr_to_tuple,
+#endif
 	.get_features		= ipv6_get_features,
 	.me			= THIS_MODULE,
 };

net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c

@@ -57,17 +57,17 @@ static int icmpv6_pkt_to_tuple(const struct sk_buff *skb,
 	return 1;
 }
 
-static int icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
-			       const struct nf_conntrack_tuple *orig)
-{
-	/* Add 1; spaces filled with 0. */
-	static u_int8_t invmap[] = {
+/* Add 1; spaces filled with 0. */
+static u_int8_t invmap[] = {
 	[ICMPV6_ECHO_REQUEST - 128]	= ICMPV6_ECHO_REPLY + 1,
 	[ICMPV6_ECHO_REPLY - 128]	= ICMPV6_ECHO_REQUEST + 1,
 	[ICMPV6_NI_QUERY - 128]		= ICMPV6_NI_QUERY + 1,
 	[ICMPV6_NI_REPLY - 128]		= ICMPV6_NI_REPLY +1
-	};
+};
 
+static int icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
+			       const struct nf_conntrack_tuple *orig)
+{
 	int type = orig->dst.u.icmp.type - 128;
 	if (type < 0 || type >= sizeof(invmap) || !invmap[type])
 		return 0;
@@ -185,7 +185,7 @@ icmpv6_error_message(struct sk_buff *skb,
 		return -NF_ACCEPT;
 	}
 
-	inproto = nf_ct_find_proto(PF_INET6, inprotonum);
+	inproto = __nf_ct_proto_find(PF_INET6, inprotonum);
 
 	/* Are they talking about one of our connections? */
 	if (!nf_ct_get_tuple(skb, inip6off, inprotoff, PF_INET6, inprotonum,
@@ -255,6 +255,60 @@ icmpv6_error(struct sk_buff *skb, unsigned int dataoff,
 	return icmpv6_error_message(skb, dataoff, ctinfo, hooknum);
 }
 
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+static int icmpv6_tuple_to_nfattr(struct sk_buff *skb,
+				  const struct nf_conntrack_tuple *t)
+{
+	NFA_PUT(skb, CTA_PROTO_ICMPV6_ID, sizeof(u_int16_t),
+		&t->src.u.icmp.id);
+	NFA_PUT(skb, CTA_PROTO_ICMPV6_TYPE, sizeof(u_int8_t),
+		&t->dst.u.icmp.type);
+	NFA_PUT(skb, CTA_PROTO_ICMPV6_CODE, sizeof(u_int8_t),
+		&t->dst.u.icmp.code);
+
+	return 0;
+
+nfattr_failure:
+	return -1;
+}
+
+static const size_t cta_min_proto[CTA_PROTO_MAX] = {
+	[CTA_PROTO_ICMPV6_TYPE-1] = sizeof(u_int8_t),
+	[CTA_PROTO_ICMPV6_CODE-1] = sizeof(u_int8_t),
+	[CTA_PROTO_ICMPV6_ID-1]   = sizeof(u_int16_t)
+};
+
+static int icmpv6_nfattr_to_tuple(struct nfattr *tb[],
+				struct nf_conntrack_tuple *tuple)
+{
+	if (!tb[CTA_PROTO_ICMPV6_TYPE-1]
+	    || !tb[CTA_PROTO_ICMPV6_CODE-1]
+	    || !tb[CTA_PROTO_ICMPV6_ID-1])
+		return -EINVAL;
+
+	if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
+		return -EINVAL;
+
+	tuple->dst.u.icmp.type =
+			*(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_TYPE-1]);
+	tuple->dst.u.icmp.code =
+			*(u_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_CODE-1]);
+	tuple->src.u.icmp.id =
+			*(u_int16_t *)NFA_DATA(tb[CTA_PROTO_ICMPV6_ID-1]);
+
+	if (tuple->dst.u.icmp.type < 128
+	    || tuple->dst.u.icmp.type - 128 >= sizeof(invmap)
+	    || !invmap[tuple->dst.u.icmp.type - 128])
+		return -EINVAL;
+
+	return 0;
+}
+#endif
+
 struct nf_conntrack_protocol nf_conntrack_protocol_icmpv6 =
 {
 	.l3proto		= PF_INET6,
@@ -267,6 +321,11 @@ struct nf_conntrack_protocol nf_conntrack_protocol_icmpv6 =
 	.packet			= icmpv6_packet,
 	.new			= icmpv6_new,
 	.error			= icmpv6_error,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.tuple_to_nfattr	= icmpv6_tuple_to_nfattr,
+	.nfattr_to_tuple	= icmpv6_nfattr_to_tuple,
+#endif
 };
 
 EXPORT_SYMBOL(nf_conntrack_protocol_icmpv6);

net/netfilter/Kconfig

@@ -95,4 +95,11 @@ config NF_CONNTRACK_FTP
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config NF_CT_NETLINK
+	tristate 'Connection tracking netlink interface (EXPERIMENTAL)'
+	depends on EXPERIMENTAL && NF_CONNTRACK && NETFILTER_NETLINK
+	depends on NF_CONNTRACK!=y || NETFILTER_NETLINK!=m
+	help
+	  This option enables support for a netlink-based userspace interface
+
 endmenu

net/netfilter/Makefile

@@ -13,3 +13,6 @@ obj-$(CONFIG_NF_CONNTRACK_FTP) += nf_conntrack_ftp.o
 
 # SCTP protocol connection tracking
 obj-$(CONFIG_NF_CT_PROTO_SCTP) += nf_conntrack_proto_sctp.o
+
+# netlink interface for nf_conntrack
+obj-$(CONFIG_NF_CT_NETLINK) += nf_conntrack_netlink.o

net/netfilter/nf_conntrack_proto_tcp.c

@@ -1148,6 +1148,63 @@ static int tcp_new(struct nf_conn *conntrack,
 	return 1;
 }
 
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
+			 const struct nf_conn *ct)
+{
+	struct nfattr *nest_parms;
+	
+	read_lock_bh(&tcp_lock);
+	nest_parms = NFA_NEST(skb, CTA_PROTOINFO_TCP);
+	NFA_PUT(skb, CTA_PROTOINFO_TCP_STATE, sizeof(u_int8_t),
+		&ct->proto.tcp.state);
+	read_unlock_bh(&tcp_lock);
+
+	NFA_NEST_END(skb, nest_parms);
+
+	return 0;
+
+nfattr_failure:
+	read_unlock_bh(&tcp_lock);
+	return -1;
+}
+
+static const size_t cta_min_tcp[CTA_PROTOINFO_TCP_MAX] = {
+	[CTA_PROTOINFO_TCP_STATE-1]	= sizeof(u_int8_t),
+};
+
+static int nfattr_to_tcp(struct nfattr *cda[], struct nf_conn *ct)
+{
+	struct nfattr *attr = cda[CTA_PROTOINFO_TCP-1];
+	struct nfattr *tb[CTA_PROTOINFO_TCP_MAX];
+
+	/* updates could not contain anything about the private
+	 * protocol info, in that case skip the parsing */
+	if (!attr)
+		return 0;
+
+        nfattr_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr);
+
+	if (nfattr_bad_size(tb, CTA_PROTOINFO_TCP_MAX, cta_min_tcp))
+		return -EINVAL;
+
+	if (!tb[CTA_PROTOINFO_TCP_STATE-1])
+		return -EINVAL;
+
+	write_lock_bh(&tcp_lock);
+	ct->proto.tcp.state = 
+		*(u_int8_t *)NFA_DATA(tb[CTA_PROTOINFO_TCP_STATE-1]);
+	write_unlock_bh(&tcp_lock);
+
+	return 0;
+}
+#endif
+  
 struct nf_conntrack_protocol nf_conntrack_protocol_tcp4 =
 {
 	.l3proto		= PF_INET,
@@ -1160,6 +1217,13 @@ struct nf_conntrack_protocol nf_conntrack_protocol_tcp4 =
 	.packet 		= tcp_packet,
 	.new 			= tcp_new,
 	.error			= tcp_error4,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.to_nfattr		= tcp_to_nfattr,
+	.from_nfattr		= nfattr_to_tcp,
+	.tuple_to_nfattr	= nf_ct_port_tuple_to_nfattr,
+	.nfattr_to_tuple	= nf_ct_port_nfattr_to_tuple,
+#endif
 };
 
 struct nf_conntrack_protocol nf_conntrack_protocol_tcp6 =
@@ -1174,6 +1238,13 @@ struct nf_conntrack_protocol nf_conntrack_protocol_tcp6 =
 	.packet 		= tcp_packet,
 	.new 			= tcp_new,
 	.error			= tcp_error6,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.to_nfattr		= tcp_to_nfattr,
+	.from_nfattr		= nfattr_to_tcp,
+	.tuple_to_nfattr	= nf_ct_port_tuple_to_nfattr,
+	.nfattr_to_tuple	= nf_ct_port_nfattr_to_tuple,
+#endif
 };
 
 EXPORT_SYMBOL(nf_conntrack_protocol_tcp4);

net/netfilter/nf_conntrack_proto_udp.c

@@ -196,6 +196,11 @@ struct nf_conntrack_protocol nf_conntrack_protocol_udp4 =
 	.packet			= udp_packet,
 	.new			= udp_new,
 	.error			= udp_error4,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.tuple_to_nfattr	= nf_ct_port_tuple_to_nfattr,
+	.nfattr_to_tuple	= nf_ct_port_nfattr_to_tuple,
+#endif
 };
 
 struct nf_conntrack_protocol nf_conntrack_protocol_udp6 =
@@ -210,6 +215,11 @@ struct nf_conntrack_protocol nf_conntrack_protocol_udp6 =
 	.packet			= udp_packet,
 	.new			= udp_new,
 	.error			= udp_error6,
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.tuple_to_nfattr	= nf_ct_port_tuple_to_nfattr,
+	.nfattr_to_tuple	= nf_ct_port_nfattr_to_tuple,
+#endif
 };
 
 EXPORT_SYMBOL(nf_conntrack_protocol_udp4);

net/netfilter/nf_conntrack_standalone.c

@@ -161,11 +161,11 @@ static int ct_seq_show(struct seq_file *s, void *v)
 	if (NF_CT_DIRECTION(hash))
 		return 0;
 
-	l3proto = nf_ct_find_l3proto(conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
+	l3proto = __nf_ct_l3proto_find(conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
 				       .tuple.src.l3num);
 
 	NF_CT_ASSERT(l3proto);
-	proto = nf_ct_find_proto(conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
+	proto = __nf_ct_proto_find(conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
 				   .tuple.src.l3num,
 				   conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
 				   .tuple.dst.protonum);
@@ -307,8 +307,8 @@ static int exp_seq_show(struct seq_file *s, void *v)
 		   expect->tuple.src.l3num,
 		   expect->tuple.dst.protonum);
 	print_tuple(s, &expect->tuple,
-		    nf_ct_find_l3proto(expect->tuple.src.l3num),
-		    nf_ct_find_proto(expect->tuple.src.l3num,
+		    __nf_ct_l3proto_find(expect->tuple.src.l3num),
+		    __nf_ct_proto_find(expect->tuple.src.l3num,
 				       expect->tuple.dst.protonum));
 	return seq_putc(s, '\n');
 }
@@ -847,7 +847,11 @@ EXPORT_SYMBOL(nf_conntrack_helper_unregister);
 EXPORT_SYMBOL(nf_ct_iterate_cleanup);
 EXPORT_SYMBOL(__nf_ct_refresh_acct);
 EXPORT_SYMBOL(nf_ct_protos);
-EXPORT_SYMBOL(nf_ct_find_proto);
+EXPORT_SYMBOL(__nf_ct_proto_find);
+EXPORT_SYMBOL(nf_ct_proto_find_get);
+EXPORT_SYMBOL(nf_ct_proto_put);
+EXPORT_SYMBOL(nf_ct_l3proto_find_get);
+EXPORT_SYMBOL(nf_ct_l3proto_put);
 EXPORT_SYMBOL(nf_ct_l3protos);
 EXPORT_SYMBOL(nf_conntrack_expect_alloc);
 EXPORT_SYMBOL(nf_conntrack_expect_put);
@@ -867,3 +871,21 @@ EXPORT_SYMBOL(nf_ct_get_tuple);
 EXPORT_SYMBOL(nf_ct_invert_tuple);
 EXPORT_SYMBOL(nf_conntrack_in);
 EXPORT_SYMBOL(__nf_conntrack_attach);
+EXPORT_SYMBOL(nf_conntrack_alloc);
+EXPORT_SYMBOL(nf_conntrack_free);
+EXPORT_SYMBOL(nf_conntrack_flush);
+EXPORT_SYMBOL(nf_ct_remove_expectations);
+EXPORT_SYMBOL(nf_ct_helper_find_get);
+EXPORT_SYMBOL(nf_ct_helper_put);
+EXPORT_SYMBOL(__nf_conntrack_helper_find_byname);
+EXPORT_SYMBOL(__nf_conntrack_find);
+EXPORT_SYMBOL(nf_ct_unlink_expect);
+EXPORT_SYMBOL(nf_conntrack_hash_insert);
+EXPORT_SYMBOL(__nf_conntrack_expect_find);
+EXPORT_SYMBOL(nf_conntrack_expect_find);
+EXPORT_SYMBOL(nf_conntrack_expect_list);
+#if defined(CONFIG_NF_CT_NETLINK) || \
+    defined(CONFIG_NF_CT_NETLINK_MODULE)
+EXPORT_SYMBOL(nf_ct_port_tuple_to_nfattr);
+EXPORT_SYMBOL(nf_ct_port_nfattr_to_tuple);
+#endif