[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

+#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 */

include/linux/netfilter_ipv4/ip_conntrack.h

@@ -209,6 +209,9 @@ struct ip_conntrack
 	/* Current number of expected connections */
 	unsigned int expecting;
 
+	/* Unique ID that identifies this conntrack*/
+	unsigned int id;
+
 	/* Helper, if any. */
 	struct ip_conntrack_helper *helper;
 
@@ -257,6 +260,9 @@ struct ip_conntrack_expect
 	/* Usage count. */
 	atomic_t use;
 
+	/* Unique ID */
+	unsigned int id;
+
 #ifdef CONFIG_IP_NF_NAT_NEEDED
 	/* This is the original per-proto part, used to map the
 	 * expected connection the way the recipient expects. */
@@ -296,7 +302,12 @@ ip_conntrack_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo)
 }
 
 /* decrement reference count on a conntrack */
-extern void ip_conntrack_put(struct ip_conntrack *ct);
+static inline void
+ip_conntrack_put(struct ip_conntrack *ct)
+{
+	IP_NF_ASSERT(ct);
+	nf_conntrack_put(&ct->ct_general);
+}
 
 /* call to create an explicit dependency on ip_conntrack. */
 extern void need_ip_conntrack(void);
@@ -331,6 +342,39 @@ extern void
 ip_ct_iterate_cleanup(int (*iter)(struct ip_conntrack *i, void *data),
 		      void *data);
 
+extern struct ip_conntrack_helper *
+__ip_conntrack_helper_find_byname(const char *);
+extern struct ip_conntrack_helper *
+ip_conntrack_helper_find_get(const struct ip_conntrack_tuple *tuple);
+extern void ip_conntrack_helper_put(struct ip_conntrack_helper *helper);
+
+extern struct ip_conntrack_protocol *
+__ip_conntrack_proto_find(u_int8_t protocol);
+extern struct ip_conntrack_protocol *
+ip_conntrack_proto_find_get(u_int8_t protocol);
+extern void ip_conntrack_proto_put(struct ip_conntrack_protocol *proto);
+
+extern void ip_ct_remove_expectations(struct ip_conntrack *ct);
+
+extern struct ip_conntrack *ip_conntrack_alloc(struct ip_conntrack_tuple *,
+					       struct ip_conntrack_tuple *);
+
+extern void ip_conntrack_free(struct ip_conntrack *ct);
+
+extern void ip_conntrack_hash_insert(struct ip_conntrack *ct);
+
+extern struct ip_conntrack_expect *
+__ip_conntrack_expect_find(const struct ip_conntrack_tuple *tuple);
+
+extern struct ip_conntrack_expect *
+ip_conntrack_expect_find_get(const struct ip_conntrack_tuple *tuple);
+
+extern struct ip_conntrack_tuple_hash *
+__ip_conntrack_find(const struct ip_conntrack_tuple *tuple,
+                    const struct ip_conntrack *ignored_conntrack);
+
+extern void ip_conntrack_flush(void);
+
 /* It's confirmed if it is, or has been in the hash table. */
 static inline int is_confirmed(struct ip_conntrack *ct)
 {

include/linux/netfilter_ipv4/ip_conntrack_core.h

@@ -2,6 +2,9 @@
 #define _IP_CONNTRACK_CORE_H
 #include <linux/netfilter.h>
 
+#define MAX_IP_CT_PROTO 256
+extern struct ip_conntrack_protocol *ip_ct_protos[MAX_IP_CT_PROTO];
+
 /* This header is used to share core functionality between the
    standalone connection tracking module, and the compatibility layer's use
    of connection tracking. */
@@ -53,6 +56,8 @@ struct ip_conntrack_ecache;
 extern void __ip_ct_deliver_cached_events(struct ip_conntrack_ecache *ec);
 #endif
 
+extern void __ip_ct_expect_unlink_destroy(struct ip_conntrack_expect *exp);
+
 extern struct list_head *ip_conntrack_hash;
 extern struct list_head ip_conntrack_expect_list;
 extern rwlock_t ip_conntrack_lock;

include/linux/netfilter_ipv4/ip_conntrack_helper.h

@@ -24,6 +24,8 @@ struct ip_conntrack_helper
 	int (*help)(struct sk_buff **pskb,
 		    struct ip_conntrack *ct,
 		    enum ip_conntrack_info conntrackinfo);
+
+	int (*to_nfattr)(struct sk_buff *skb, const struct ip_conntrack *ct);
 };
 
 extern int ip_conntrack_helper_register(struct ip_conntrack_helper *);

include/linux/netfilter_ipv4/ip_conntrack_protocol.h

@@ -2,6 +2,7 @@
 #ifndef _IP_CONNTRACK_PROTOCOL_H
 #define _IP_CONNTRACK_PROTOCOL_H
 #include <linux/netfilter_ipv4/ip_conntrack.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
 
 struct seq_file;
 
@@ -47,22 +48,22 @@ struct ip_conntrack_protocol
 	int (*error)(struct sk_buff *skb, enum ip_conntrack_info *ctinfo,
 		     unsigned int hooknum);
 
+	/* convert protoinfo to nfnetink attributes */
+	int (*to_nfattr)(struct sk_buff *skb, struct nfattr *nfa,
+			 const struct ip_conntrack *ct);
+
+	int (*tuple_to_nfattr)(struct sk_buff *skb,
+			       const struct ip_conntrack_tuple *t);
+	int (*nfattr_to_tuple)(struct nfattr *tb[],
+			       struct ip_conntrack_tuple *t);
+
 	/* Module (if any) which this is connected to. */
 	struct module *me;
 };
 
-#define MAX_IP_CT_PROTO 256
-extern struct ip_conntrack_protocol *ip_ct_protos[MAX_IP_CT_PROTO];
-
 /* Protocol registration. */
 extern int ip_conntrack_protocol_register(struct ip_conntrack_protocol *proto);
 extern void ip_conntrack_protocol_unregister(struct ip_conntrack_protocol *proto);
-
-static inline struct ip_conntrack_protocol *ip_ct_find_proto(u_int8_t protocol)
-{
-	return ip_ct_protos[protocol];
-}
-
 /* Existing built-in protocols */
 extern struct ip_conntrack_protocol ip_conntrack_protocol_tcp;
 extern struct ip_conntrack_protocol ip_conntrack_protocol_udp;
@@ -73,6 +74,11 @@ extern int ip_conntrack_protocol_tcp_init(void);
 /* Log invalid packets */
 extern unsigned int ip_ct_log_invalid;
 
+extern int ip_ct_port_tuple_to_nfattr(struct sk_buff *,
+				      const struct ip_conntrack_tuple *);
+extern int ip_ct_port_nfattr_to_tuple(struct nfattr *tb[],
+				      struct ip_conntrack_tuple *);
+
 #ifdef CONFIG_SYSCTL
 #ifdef DEBUG_INVALID_PACKETS
 #define LOG_INVALID(proto) \

include/linux/netfilter_ipv4/ip_nat_protocol.h

@@ -4,6 +4,9 @@
 #include <linux/init.h>
 #include <linux/list.h>
 
+#include <linux/netfilter_ipv4/ip_nat.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
 struct iphdr;
 struct ip_nat_range;
 
@@ -15,6 +18,8 @@ struct ip_nat_protocol
 	/* Protocol number. */
 	unsigned int protonum;
 
+	struct module *me;
+
 	/* Translate a packet to the target according to manip type.
 	   Return true if succeeded. */
 	int (*manip_pkt)(struct sk_buff **pskb,
@@ -43,19 +48,20 @@ struct ip_nat_protocol
 
 	unsigned int (*print_range)(char *buffer,
 				    const struct ip_nat_range *range);
-};
 
-#define MAX_IP_NAT_PROTO 256
-extern struct ip_nat_protocol *ip_nat_protos[MAX_IP_NAT_PROTO];
+	int (*range_to_nfattr)(struct sk_buff *skb,
+			       const struct ip_nat_range *range);
+
+	int (*nfattr_to_range)(struct nfattr *tb[],
+			       struct ip_nat_range *range);
+};
 
 /* Protocol registration. */
 extern int ip_nat_protocol_register(struct ip_nat_protocol *proto);
 extern void ip_nat_protocol_unregister(struct ip_nat_protocol *proto);
 
-static inline struct ip_nat_protocol *ip_nat_find_proto(u_int8_t protocol)
-{
-	return ip_nat_protos[protocol];
-}
+extern struct ip_nat_protocol *ip_nat_proto_find_get(u_int8_t protocol);
+extern void ip_nat_proto_put(struct ip_nat_protocol *proto);
 
 /* Built-in protocols. */
 extern struct ip_nat_protocol ip_nat_protocol_tcp;
@@ -67,4 +73,9 @@ extern int init_protocols(void) __init;
 extern void cleanup_protocols(void);
 extern struct ip_nat_protocol *find_nat_proto(u_int16_t protonum);
 
+extern int ip_nat_port_range_to_nfattr(struct sk_buff *skb,
+				       const struct ip_nat_range *range);
+extern int ip_nat_port_nfattr_to_range(struct nfattr *tb[],
+				       struct ip_nat_range *range);
+
 #endif /*_IP_NAT_PROTO_H*/

net/ipv4/netfilter/Kconfig

@@ -702,5 +702,12 @@ config IP_NF_ARP_MANGLE
 	  Allows altering the ARP packet payload: source and destination
 	  hardware and network addresses.
 
+config IP_NF_CONNTRACK_NETLINK
+        tristate 'Connection tracking netlink interface'
+        depends on IP_NF_CONNTRACK && NETFILTER_NETLINK
+        help
+          This option enables support for a netlink-based userspace interface
+
+
 endmenu
 

net/ipv4/netfilter/Makefile

@@ -9,6 +9,10 @@ iptable_nat-objs	:= ip_nat_standalone.o ip_nat_rule.o ip_nat_core.o ip_nat_helpe
 # connection tracking
 obj-$(CONFIG_IP_NF_CONNTRACK) += ip_conntrack.o
 
+# conntrack netlink interface
+obj-$(CONFIG_IP_NF_CONNTRACK_NETLINK) += ip_conntrack_netlink.o
+
+
 # SCTP protocol connection tracking
 obj-$(CONFIG_IP_NF_CT_PROTO_SCTP) += ip_conntrack_proto_sctp.o
 

net/ipv4/netfilter/ip_conntrack_proto_icmp.c

@@ -109,16 +109,17 @@ static int icmp_packet(struct ip_conntrack *ct,
 	return NF_ACCEPT;
 }
 
+static u_int8_t valid_new[] = { 
+	[ICMP_ECHO] = 1,
+	[ICMP_TIMESTAMP] = 1,
+	[ICMP_INFO_REQUEST] = 1,
+	[ICMP_ADDRESS] = 1 
+};
+
 /* Called when a new connection for this protocol found. */
 static int icmp_new(struct ip_conntrack *conntrack,
 		    const struct sk_buff *skb)
 {
-	static u_int8_t valid_new[]
-		= { [ICMP_ECHO] = 1,
-		    [ICMP_TIMESTAMP] = 1,
-		    [ICMP_INFO_REQUEST] = 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]) {
 		/* Can't create a new ICMP `conn' with this. */
@@ -159,11 +160,12 @@ icmp_error_message(struct sk_buff *skb,
 		return NF_ACCEPT;
 	}
 
-	innerproto = ip_ct_find_proto(inside->ip.protocol);
+	innerproto = ip_conntrack_proto_find_get(inside->ip.protocol);
 	dataoff = skb->nh.iph->ihl*4 + sizeof(inside->icmp) + inside->ip.ihl*4;
 	/* Are they talking about one of our connections? */
 	if (!ip_ct_get_tuple(&inside->ip, skb, dataoff, &origtuple, innerproto)) {
 		DEBUGP("icmp_error: ! get_tuple p=%u", inside->ip.protocol);
+		ip_conntrack_proto_put(innerproto);
 		return NF_ACCEPT;
 	}
 
@@ -171,8 +173,10 @@ icmp_error_message(struct sk_buff *skb,
 	   been preserved inside the ICMP. */
 	if (!ip_ct_invert_tuple(&innertuple, &origtuple, innerproto)) {
 		DEBUGP("icmp_error_track: Can't invert tuple\n");
+		ip_conntrack_proto_put(innerproto);
 		return NF_ACCEPT;
 	}
+	ip_conntrack_proto_put(innerproto);
 
 	*ctinfo = IP_CT_RELATED;
 
@@ -266,6 +270,47 @@ checksum_skipped:
 	return icmp_error_message(skb, ctinfo, hooknum);
 }
 
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+static int icmp_tuple_to_nfattr(struct sk_buff *skb,
+				const struct ip_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);
+
+	if (t->dst.u.icmp.type >= sizeof(valid_new) 
+	    || !valid_new[t->dst.u.icmp.type])
+		return -EINVAL;
+
+	return 0;
+
+nfattr_failure:
+	return -1;
+}
+
+static int icmp_nfattr_to_tuple(struct nfattr *tb[],
+				struct ip_conntrack_tuple *tuple)
+{
+	if (!tb[CTA_PROTO_ICMP_TYPE-1]
+	    || !tb[CTA_PROTO_ICMP_CODE-1]
+	    || !tb[CTA_PROTO_ICMP_ID-1])
+		return -1;
+
+	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_int8_t *)NFA_DATA(tb[CTA_PROTO_ICMP_ID-1]);
+
+	return 0;
+}
+#endif
+
 struct ip_conntrack_protocol ip_conntrack_protocol_icmp =
 {
 	.proto 			= IPPROTO_ICMP,
@@ -277,4 +322,9 @@ struct ip_conntrack_protocol ip_conntrack_protocol_icmp =
 	.packet			= icmp_packet,
 	.new			= icmp_new,
 	.error			= icmp_error,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+	.tuple_to_nfattr	= icmp_tuple_to_nfattr,
+	.nfattr_to_tuple	= icmp_nfattr_to_tuple,
+#endif
 };

net/ipv4/netfilter/ip_conntrack_proto_sctp.c

@@ -505,7 +505,12 @@ static struct ip_conntrack_protocol ip_conntrack_protocol_sctp = {
 	.packet 	 = sctp_packet, 
 	.new 		 = sctp_new, 
 	.destroy 	 = NULL, 
-	.me 		 = THIS_MODULE 
+	.me 		 = THIS_MODULE,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+	.tuple_to_nfattr = ip_ct_port_tuple_to_nfattr,
+	.nfattr_to_tuple = ip_ct_port_nfattr_to_tuple,
+#endif
 };
 
 #ifdef CONFIG_SYSCTL

net/ipv4/netfilter/ip_conntrack_proto_tcp.c

@@ -336,6 +336,23 @@ static int tcp_print_conntrack(struct seq_file *s,
 	return seq_printf(s, "%s ", tcp_conntrack_names[state]);
 }
 
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+static int tcp_to_nfattr(struct sk_buff *skb, struct nfattr *nfa,
+			 const struct ip_conntrack *ct)
+{
+	read_lock_bh(&tcp_lock);
+	NFA_PUT(skb, CTA_PROTOINFO_TCP_STATE, sizeof(u_int8_t),
+		&ct->proto.tcp.state);
+	read_unlock_bh(&tcp_lock);
+
+	return 0;
+
+nfattr_failure:
+	return -1;
+}
+#endif
+
 static unsigned int get_conntrack_index(const struct tcphdr *tcph)
 {
 	if (tcph->rst) return TCP_RST_SET;
@@ -1100,4 +1117,10 @@ struct ip_conntrack_protocol ip_conntrack_protocol_tcp =
 	.packet 		= tcp_packet,
 	.new 			= tcp_new,
 	.error			= tcp_error,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+	.to_nfattr		= tcp_to_nfattr,
+	.tuple_to_nfattr	= ip_ct_port_tuple_to_nfattr,
+	.nfattr_to_tuple	= ip_ct_port_nfattr_to_tuple,
+#endif
 };

net/ipv4/netfilter/ip_conntrack_proto_udp.c

@@ -145,4 +145,9 @@ struct ip_conntrack_protocol ip_conntrack_protocol_udp =
 	.packet			= udp_packet,
 	.new			= udp_new,
 	.error			= udp_error,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+	.tuple_to_nfattr	= ip_ct_port_tuple_to_nfattr,
+	.nfattr_to_tuple	= ip_ct_port_nfattr_to_tuple,
+#endif
 };

net/ipv4/netfilter/ip_conntrack_standalone.c

@@ -5,7 +5,7 @@
 */
 
 /* (C) 1999-2001 Paul `Rusty' Russell
- * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -147,8 +147,7 @@ static int ct_seq_show(struct seq_file *s, void *v)
 	if (DIRECTION(hash))
 		return 0;
 
-	proto = ip_ct_find_proto(conntrack->tuplehash[IP_CT_DIR_ORIGINAL]
-			       .tuple.dst.protonum);
+	proto = __ip_conntrack_proto_find(conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum);
 	IP_NF_ASSERT(proto);
 
 	if (seq_printf(s, "%-8s %u %ld ",
@@ -283,7 +282,7 @@ static int exp_seq_show(struct seq_file *s, void *v)
 	seq_printf(s, "proto=%u ", expect->tuple.dst.protonum);
 
 	print_tuple(s, &expect->tuple,
-		    ip_ct_find_proto(expect->tuple.dst.protonum));
+		    __ip_conntrack_proto_find(expect->tuple.dst.protonum));
 	return seq_putc(s, '\n');
 }
 
@@ -992,12 +991,16 @@ EXPORT_SYMBOL(ip_conntrack_helper_register);
 EXPORT_SYMBOL(ip_conntrack_helper_unregister);
 EXPORT_SYMBOL(ip_ct_iterate_cleanup);
 EXPORT_SYMBOL(ip_ct_refresh_acct);
-EXPORT_SYMBOL(ip_ct_protos);
-EXPORT_SYMBOL(ip_ct_find_proto);
+
 EXPORT_SYMBOL(ip_conntrack_expect_alloc);
 EXPORT_SYMBOL(ip_conntrack_expect_put);
+EXPORT_SYMBOL_GPL(ip_conntrack_expect_find_get);
 EXPORT_SYMBOL(ip_conntrack_expect_related);
 EXPORT_SYMBOL(ip_conntrack_unexpect_related);
+EXPORT_SYMBOL_GPL(ip_conntrack_expect_list);
+EXPORT_SYMBOL_GPL(__ip_conntrack_expect_find);
+EXPORT_SYMBOL_GPL(__ip_ct_expect_unlink_destroy);
+
 EXPORT_SYMBOL(ip_conntrack_tuple_taken);
 EXPORT_SYMBOL(ip_ct_gather_frags);
 EXPORT_SYMBOL(ip_conntrack_htable_size);
@@ -1005,7 +1008,28 @@ EXPORT_SYMBOL(ip_conntrack_lock);
 EXPORT_SYMBOL(ip_conntrack_hash);
 EXPORT_SYMBOL(ip_conntrack_untracked);
 EXPORT_SYMBOL_GPL(ip_conntrack_find_get);
-EXPORT_SYMBOL_GPL(ip_conntrack_put);
 #ifdef CONFIG_IP_NF_NAT_NEEDED
 EXPORT_SYMBOL(ip_conntrack_tcp_update);
 #endif
+
+EXPORT_SYMBOL_GPL(ip_conntrack_flush);
+EXPORT_SYMBOL_GPL(__ip_conntrack_find);
+
+EXPORT_SYMBOL_GPL(ip_conntrack_alloc);
+EXPORT_SYMBOL_GPL(ip_conntrack_free);
+EXPORT_SYMBOL_GPL(ip_conntrack_hash_insert);
+
+EXPORT_SYMBOL_GPL(ip_ct_remove_expectations);
+
+EXPORT_SYMBOL_GPL(ip_conntrack_helper_find_get);
+EXPORT_SYMBOL_GPL(ip_conntrack_helper_put);
+EXPORT_SYMBOL_GPL(__ip_conntrack_helper_find_byname);
+
+EXPORT_SYMBOL_GPL(ip_conntrack_proto_find_get);
+EXPORT_SYMBOL_GPL(ip_conntrack_proto_put);
+EXPORT_SYMBOL_GPL(__ip_conntrack_proto_find);
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+EXPORT_SYMBOL_GPL(ip_ct_port_tuple_to_nfattr);
+EXPORT_SYMBOL_GPL(ip_ct_port_nfattr_to_tuple);
+#endif

net/ipv4/netfilter/ip_nat_core.c

@@ -47,8 +47,39 @@ DEFINE_RWLOCK(ip_nat_lock);
 static unsigned int ip_nat_htable_size;
 
 static struct list_head *bysource;
+
+#define MAX_IP_NAT_PROTO 256
 struct ip_nat_protocol *ip_nat_protos[MAX_IP_NAT_PROTO];
 
+static inline struct ip_nat_protocol *
+__ip_nat_proto_find(u_int8_t protonum)
+{
+	return ip_nat_protos[protonum];
+}
+
+struct ip_nat_protocol *
+ip_nat_proto_find_get(u_int8_t protonum)
+{
+	struct ip_nat_protocol *p;
+
+	/* we need to disable preemption to make sure 'p' doesn't get
+	 * removed until we've grabbed the reference */
+	preempt_disable();
+	p = __ip_nat_proto_find(protonum);
+	if (p) {
+		if (!try_module_get(p->me))
+			p = &ip_nat_unknown_protocol;
+	}
+	preempt_enable();
+
+	return p;
+}
+
+void
+ip_nat_proto_put(struct ip_nat_protocol *p)
+{
+	module_put(p->me);
+}
 
 /* We keep an extra hash for each conntrack, for fast searching. */
 static inline unsigned int
@@ -103,7 +134,8 @@ static int
 in_range(const struct ip_conntrack_tuple *tuple,
 	 const struct ip_nat_range *range)
 {
-	struct ip_nat_protocol *proto = ip_nat_find_proto(tuple->dst.protonum);
+	struct ip_nat_protocol *proto = 
+				__ip_nat_proto_find(tuple->dst.protonum);
 
 	/* If we are supposed to map IPs, then we must be in the
 	   range specified, otherwise let this drag us onto a new src IP. */
@@ -216,8 +248,7 @@ get_unique_tuple(struct ip_conntrack_tuple *tuple,
 		 struct ip_conntrack *conntrack,
 		 enum ip_nat_manip_type maniptype)
 {
-	struct ip_nat_protocol *proto
-		= ip_nat_find_proto(orig_tuple->dst.protonum);
+	struct ip_nat_protocol *proto;
 
 	/* 1) If this srcip/proto/src-proto-part is currently mapped,
 	   and that same mapping gives a unique tuple within the given
@@ -242,14 +273,20 @@ get_unique_tuple(struct ip_conntrack_tuple *tuple,
 	/* 3) The per-protocol part of the manip is made to map into
 	   the range to make a unique tuple. */
 
+	proto = ip_nat_proto_find_get(orig_tuple->dst.protonum);
+
 	/* Only bother mapping if it's not already in range and unique */
 	if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)
 	     || proto->in_range(tuple, maniptype, &range->min, &range->max))
-	    && !ip_nat_used_tuple(tuple, conntrack))
+	    && !ip_nat_used_tuple(tuple, conntrack)) {
+		ip_nat_proto_put(proto);
 		return;
+	}
 
 	/* Last change: get protocol to try to obtain unique tuple. */
 	proto->unique_tuple(tuple, range, maniptype, conntrack);
+
+	ip_nat_proto_put(proto);
 }
 
 unsigned int
@@ -320,6 +357,7 @@ manip_pkt(u_int16_t proto,
 	  enum ip_nat_manip_type maniptype)
 {
 	struct iphdr *iph;
+	struct ip_nat_protocol *p;
 
 	if (!skb_ip_make_writable(pskb, iphdroff + sizeof(*iph)))
 		return 0;
@@ -327,9 +365,12 @@ manip_pkt(u_int16_t proto,
 	iph = (void *)(*pskb)->data + iphdroff;
 
 	/* Manipulate protcol part. */
-	if (!ip_nat_find_proto(proto)->manip_pkt(pskb, iphdroff,
-	                                         target, maniptype))
+	p = ip_nat_proto_find_get(proto);
+	if (!p->manip_pkt(pskb, iphdroff, target, maniptype)) {
+		ip_nat_proto_put(p);
 		return 0;
+	}
+	ip_nat_proto_put(p);
 
 	iph = (void *)(*pskb)->data + iphdroff;
 
@@ -425,7 +466,8 @@ int icmp_reply_translation(struct sk_buff **pskb,
 
 	if (!ip_ct_get_tuple(&inside->ip, *pskb, (*pskb)->nh.iph->ihl*4 +
 	                     sizeof(struct icmphdr) + inside->ip.ihl*4,
-	                     &inner, ip_ct_find_proto(inside->ip.protocol)))
+	                     &inner,
+			     __ip_conntrack_proto_find(inside->ip.protocol)))
 		return 0;
 
 	/* Change inner back to look like incoming packet.  We do the
@@ -495,6 +537,49 @@ void ip_nat_protocol_unregister(struct ip_nat_protocol *proto)
 	synchronize_net();
 }
 
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+int
+ip_nat_port_range_to_nfattr(struct sk_buff *skb, 
+			    const struct ip_nat_range *range)
+{
+	NFA_PUT(skb, CTA_PROTONAT_PORT_MIN, sizeof(u_int16_t),
+		&range->min.tcp.port);
+	NFA_PUT(skb, CTA_PROTONAT_PORT_MAX, sizeof(u_int16_t),
+		&range->max.tcp.port);
+
+	return 0;
+
+nfattr_failure:
+	return -1;
+}
+
+int
+ip_nat_port_nfattr_to_range(struct nfattr *tb[], struct ip_nat_range *range)
+{
+	int ret = 0;
+	
+	/* we have to return whether we actually parsed something or not */
+
+	if (tb[CTA_PROTONAT_PORT_MIN-1]) {
+		ret = 1;
+		range->min.tcp.port = 
+			*(u_int16_t *)NFA_DATA(tb[CTA_PROTONAT_PORT_MIN-1]);
+	}
+	
+	if (!tb[CTA_PROTONAT_PORT_MAX-1]) {
+		if (ret) 
+			range->max.tcp.port = range->min.tcp.port;
+	} else {
+		ret = 1;
+		range->max.tcp.port = 
+			*(u_int16_t *)NFA_DATA(tb[CTA_PROTONAT_PORT_MAX-1]);
+	}
+
+	return ret;
+}
+#endif
+
 int __init ip_nat_init(void)
 {
 	size_t i;

net/ipv4/netfilter/ip_nat_proto_icmp.c

@@ -107,10 +107,15 @@ icmp_print_range(char *buffer, const struct ip_nat_range *range)
 }
 
 struct ip_nat_protocol ip_nat_protocol_icmp
-= { "ICMP", IPPROTO_ICMP,
+= { "ICMP", IPPROTO_ICMP, THIS_MODULE,
     icmp_manip_pkt,
     icmp_in_range,
     icmp_unique_tuple,
     icmp_print,
-    icmp_print_range
+    icmp_print_range,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+    ip_nat_port_range_to_nfattr,
+    ip_nat_port_nfattr_to_range,
+#endif
 };

net/ipv4/netfilter/ip_nat_proto_tcp.c

@@ -12,6 +12,7 @@
 #include <linux/ip.h>
 #include <linux/tcp.h>
 #include <linux/if.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
 #include <linux/netfilter_ipv4/ip_nat.h>
 #include <linux/netfilter_ipv4/ip_nat_rule.h>
 #include <linux/netfilter_ipv4/ip_nat_protocol.h>
@@ -170,10 +171,15 @@ tcp_print_range(char *buffer, const struct ip_nat_range *range)
 }
 
 struct ip_nat_protocol ip_nat_protocol_tcp
-= { "TCP", IPPROTO_TCP,
+= { "TCP", IPPROTO_TCP, THIS_MODULE,
     tcp_manip_pkt,
     tcp_in_range,
     tcp_unique_tuple,
     tcp_print,
-    tcp_print_range
+    tcp_print_range,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+    ip_nat_port_range_to_nfattr,
+    ip_nat_port_nfattr_to_range,
+#endif
 };

net/ipv4/netfilter/ip_nat_proto_udp.c

@@ -157,10 +157,15 @@ udp_print_range(char *buffer, const struct ip_nat_range *range)
 }
 
 struct ip_nat_protocol ip_nat_protocol_udp
-= { "UDP", IPPROTO_UDP,
+= { "UDP", IPPROTO_UDP, THIS_MODULE,
     udp_manip_pkt,
     udp_in_range,
     udp_unique_tuple,
     udp_print,
-    udp_print_range
+    udp_print_range,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+    defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+    ip_nat_port_range_to_nfattr,
+    ip_nat_port_nfattr_to_range,
+#endif
 };

net/ipv4/netfilter/ip_nat_proto_unknown.c

@@ -61,7 +61,7 @@ unknown_print_range(char *buffer, const struct ip_nat_range *range)
 }
 
 struct ip_nat_protocol ip_nat_unknown_protocol = {
-	"unknown", 0,
+	"unknown", 0, THIS_MODULE,
 	unknown_manip_pkt,
 	unknown_in_range,
 	unknown_unique_tuple,

net/ipv4/netfilter/ip_nat_standalone.c

@@ -394,6 +394,8 @@ module_exit(fini);
 EXPORT_SYMBOL(ip_nat_setup_info);
 EXPORT_SYMBOL(ip_nat_protocol_register);
 EXPORT_SYMBOL(ip_nat_protocol_unregister);
+EXPORT_SYMBOL_GPL(ip_nat_proto_find_get);
+EXPORT_SYMBOL_GPL(ip_nat_proto_put);
 EXPORT_SYMBOL(ip_nat_cheat_check);
 EXPORT_SYMBOL(ip_nat_mangle_tcp_packet);
 EXPORT_SYMBOL(ip_nat_mangle_udp_packet);

net/netfilter/nfnetlink.c

@@ -121,6 +121,7 @@ void __nfa_fill(struct sk_buff *skb, int attrtype, int attrlen,
 	nfa->nfa_type = attrtype;
 	nfa->nfa_len  = size;
 	memcpy(NFA_DATA(nfa), data, attrlen);
+	memset(NFA_DATA(nfa) + attrlen, 0, NFA_ALIGN(size) - size);
 }
 
 int nfattr_parse(struct nfattr *tb[], int maxattr, struct nfattr *nfa, int len)