Big netfilter newnat patch for 2.5.7:

- support for multiple expected connections
  (necessary for protocols like H.323, SIP, PPTP)
- helper-definable limit of unconfirmed expectations
- timeouts for expectations
- full graph of connection relations, even after expectation confirmed
- various changes in the API towards conntrack and NAT helper
- automatic conntrack helper loading when at helper is loaded
- NAT mangling of TCP SACK in case of sequence number alteration
  (no need to delete SACKPERM anymore, I hope Alexey is happy now)

include/linux/netfilter_ipv4/ip_conntrack.h

@@ -6,6 +6,7 @@
 
 #include <linux/config.h>
 #include <linux/netfilter_ipv4/ip_conntrack_tuple.h>
+#include <asm/atomic.h>
 
 enum ip_conntrack_info
 {
@@ -62,27 +63,58 @@ do {									\
 #define IP_NF_ASSERT(x)
 #endif
 
+#ifdef CONFIG_IP_NF_NAT_NEEDED
+#include <linux/netfilter_ipv4/ip_nat.h>
+#endif
+
+/* Add protocol helper include file here */
+#include <linux/netfilter_ipv4/ip_conntrack_ftp.h>
+#include <linux/netfilter_ipv4/ip_conntrack_irc.h>
+
 struct ip_conntrack_expect
 {
-	/* Internal linked list */
+	/* Internal linked list (global expectation list) */
 	struct list_head list;
 
+	/* expectation list for this master */
+	struct list_head expected_list;
+
+	/* The conntrack of the master connection */
+	struct ip_conntrack *expectant;
+
+	/* The conntrack of the sibling connection, set after
+	 * expectation arrived */
+	struct ip_conntrack *sibling;
+
+	/* Tuple saved for conntrack */
+	struct ip_conntrack_tuple ct_tuple;
+
+	/* Timer function; deletes the expectation. */
+	struct timer_list timeout;
+
+	/* Data filled out by the conntrack helpers follow: */
+
 	/* We expect this tuple, with the following mask */
 	struct ip_conntrack_tuple tuple, mask;
 
 	/* Function to call after setup and insertion */
 	int (*expectfn)(struct ip_conntrack *new);
 
-	/* The conntrack we are part of (set iff we're live) */
-	struct ip_conntrack *expectant;
-};
+	/* At which sequence number did this expectation occur */
+	u_int32_t seq;
+  
+	union {
+		/* insert conntrack helper private data (expect) here */
+		struct ip_ct_ftp_expect exp_ftp_info;
+		struct ip_ct_irc_expect exp_irc_info;
   
 #ifdef CONFIG_IP_NF_NAT_NEEDED
-#include <linux/netfilter_ipv4/ip_nat.h>
+ 		union {
+			/* insert nat helper private data (expect) here */
+		} nat;
 #endif
-
-#include <linux/netfilter_ipv4/ip_conntrack_ftp.h>
-#include <linux/netfilter_ipv4/ip_conntrack_irc.h>
+	} help;
+};
 
 struct ip_conntrack
 {
@@ -101,10 +133,13 @@ struct ip_conntrack
 
 	/* If we're expecting another related connection, this will be
            in expected linked list */
-	struct ip_conntrack_expect expected;
+	struct list_head sibling_list;
+	
+	/* Current number of expected connections */
+	unsigned int expecting;
 
-	/* If we were expected by another connection, this will be it */
-	struct nf_ct_info master;
+	/* If we were expected by an expectation, this will be it */
+	struct ip_conntrack_expect *master;
 
 	/* Helper, if any. */
 	struct ip_conntrack_helper *helper;
@@ -121,8 +156,9 @@ struct ip_conntrack
 	} proto;
 
 	union {
-		struct ip_ct_ftp ct_ftp_info;
-		struct ip_ct_irc ct_irc_info;
+		/* insert conntrack helper private data (master) here */
+		struct ip_ct_ftp_master ct_ftp_info;
+		struct ip_ct_irc_master ct_irc_info;
 	} help;
 
 #ifdef CONFIG_IP_NF_NAT_NEEDED
@@ -140,6 +176,9 @@ struct ip_conntrack
 
 };
 
+/* get master conntrack via master expectation */
+#define master_ct(conntr) (conntr->master ? conntr->master->expectant : NULL)
+
 /* Alter reply tuple (maybe alter helper).  If it's already taken,
    return 0 and don't do alteration. */
 extern int

include/linux/netfilter_ipv4/ip_conntrack_core.h

@@ -15,7 +15,7 @@ extern int ip_conntrack_init(void);
 extern void ip_conntrack_cleanup(void);
 
 struct ip_conntrack_protocol;
-extern struct ip_conntrack_protocol *find_proto(u_int8_t protocol);
+extern struct ip_conntrack_protocol *ip_ct_find_proto(u_int8_t protocol);
 /* Like above, but you already have conntrack read lock. */
 extern struct ip_conntrack_protocol *__find_proto(u_int8_t protocol);
 extern struct list_head protocol_list;

include/linux/netfilter_ipv4/ip_conntrack_ftp.h

@@ -11,6 +11,8 @@
 /* Protects ftp part of conntracks */
 DECLARE_LOCK_EXTERN(ip_ftp_lock);
 
+#define FTP_PORT	21
+
 enum ip_ct_ftp_type
 {
 	/* PORT command from client */
@@ -23,18 +25,20 @@ enum ip_ct_ftp_type
 	IP_CT_FTP_EPSV,
 };
 
-/* We record seq number and length of ftp ip/port text here: all in
-   host order. */
-struct ip_ct_ftp
+/* This structure is per expected connection */
+struct ip_ct_ftp_expect
 {
-	/* This tells NAT that this is an ftp connection */
-	int is_ftp;
-	u_int32_t seq;
-	/* 0 means not found yet */
-	u_int32_t len;
-	enum ip_ct_ftp_type ftptype;
-	/* Port that was to be used */
-	u_int16_t port;
+	/* We record seq number and length of ftp ip/port text here: all in
+	 * host order. */
+
+ 	/* sequence number of IP address in packet is in ip_conntrack_expect */
+	u_int32_t len;			/* length of IP address */
+	enum ip_ct_ftp_type ftptype;	/* PORT or PASV ? */
+	u_int16_t port; 		/* TCP port that was to be used */
+};
+
+/* This structure exists only once per master */
+struct ip_ct_ftp_master {
 	/* Next valid seq position for cmd matching after newline */
 	u_int32_t seq_aft_nl[IP_CT_DIR_MAX];
 	/* 0 means seq_match_aft_nl not set */

include/linux/netfilter_ipv4/ip_conntrack_helper.h

@@ -5,10 +5,19 @@
 
 struct module;
 
+/* Reuse expectation when max_expected reached */
+#define IP_CT_HELPER_F_REUSE_EXPECT	0x01
+
 struct ip_conntrack_helper
 {	
-	/* Internal use. */
-	struct list_head list;
+	struct list_head list; 		/* Internal use. */
+
+	const char *name;		/* name of the module */
+	unsigned char flags;		/* Flags (see above) */
+	struct module *me;		/* pointer to self */
+	unsigned int max_expected;	/* Maximum number of concurrent 
+					 * expected connections */
+	unsigned int timeout;		/* timeout for expecteds */
 
 	/* Mask of things we will help (compared against server response) */
 	struct ip_conntrack_tuple tuple;
@@ -24,11 +33,13 @@ struct ip_conntrack_helper
 extern int ip_conntrack_helper_register(struct ip_conntrack_helper *);
 extern void ip_conntrack_helper_unregister(struct ip_conntrack_helper *);
 
-/* Add an expected connection: can only have one per connection */
+extern struct ip_conntrack_helper *ip_ct_find_helper(const struct ip_conntrack_tuple *tuple);
+
+/* Add an expected connection: can have more than one per connection */
 extern int ip_conntrack_expect_related(struct ip_conntrack *related_to,
-				       const struct ip_conntrack_tuple *tuple,
-				       const struct ip_conntrack_tuple *mask,
-				       int (*expectfn)(struct ip_conntrack *));
-extern void ip_conntrack_unexpect_related(struct ip_conntrack *related_to);
+				       struct ip_conntrack_expect *exp);
+extern int ip_conntrack_change_expect(struct ip_conntrack_expect *expect,
+				      struct ip_conntrack_tuple *newtuple);
+extern void ip_conntrack_unexpect_related(struct ip_conntrack_expect *exp);
 
 #endif /*_IP_CONNTRACK_HELPER_H*/

include/linux/netfilter_ipv4/ip_conntrack_irc.h

@@ -20,7 +20,7 @@
 
 #include <linux/netfilter_ipv4/lockhelp.h>
 
-#define IP_CONNTR_IRC	2
+#define IRC_PORT	6667
 
 struct dccproto {
 	char* match;
@@ -32,16 +32,18 @@ DECLARE_LOCK_EXTERN(ip_irc_lock);
 
 /* We record seq number and length of irc ip/port text here: all in
    host order. */
-struct ip_ct_irc
+
+/* This structure is per expected connection */
+struct ip_ct_irc_expect
 {
-	/* This tells NAT that this is an IRC connection */
-	int is_irc;
-	/* sequence number where address part of DCC command begins */
-	u_int32_t seq;
-	/* 0 means not found yet */
+	/* length of IP address */
 	u_int32_t len;
 	/* Port that was to be used */
 	u_int16_t port;
 };
 
+/* This structure exists only once per master */
+struct ip_ct_irc_master {
+};
+
 #endif /* _IP_CONNTRACK_IRC_H */

include/linux/netfilter_ipv4/ip_conntrack_protocol.h

@@ -45,6 +45,10 @@ struct ip_conntrack_protocol
 	/* Called when a conntrack entry is destroyed */
 	void (*destroy)(struct ip_conntrack *conntrack);
 
+	/* Has to decide if a expectation matches one packet or not */
+	int (*exp_matches_pkt)(struct ip_conntrack_expect *exp,
+			       struct sk_buff **pskb);
+
 	/* Module (if any) which this is connected to. */
 	struct module *me;
 };

include/linux/netfilter_ipv4/ip_nat_helper.h

@@ -6,10 +6,19 @@
 
 struct sk_buff;
 
+/* Flags */
+/* NAT helper must be called on every packet (for TCP) */
+#define IP_NAT_HELPER_F_ALWAYS		0x01
+/* Standalone NAT helper, without a conntrack part */
+#define IP_NAT_HELPER_F_STANDALONE	0x02
+
 struct ip_nat_helper
 {
-	/* Internal use */
-	struct list_head list;
+	struct list_head list;		/* Internal use */
+
+	const char *name;		/* name of the module */
+	unsigned char flags;		/* Flags (see above) */
+	struct module *me;		/* pointer to self */
 	
 	/* Mask of things we will help: vs. tuple from server */
 	struct ip_conntrack_tuple tuple;
@@ -17,12 +26,17 @@ struct ip_nat_helper
 	
 	/* Helper function: returns verdict */
 	unsigned int (*help)(struct ip_conntrack *ct,
+			     struct ip_conntrack_expect *exp,
 			     struct ip_nat_info *info,
 			     enum ip_conntrack_info ctinfo,
 			     unsigned int hooknum,
 			     struct sk_buff **pskb);
 
-	const char *name;
+	/* Returns verdict and sets up NAT for this connection */
+	unsigned int (*expect)(struct sk_buff **pskb,
+			       unsigned int hooknum,
+			       struct ip_conntrack *ct,
+			       struct ip_nat_info *info);
 };
 
 extern struct list_head helpers;
@@ -39,5 +53,5 @@ extern int ip_nat_mangle_tcp_packet(struct sk_buff **skb,
 extern int ip_nat_seq_adjust(struct sk_buff *skb,
 				struct ip_conntrack *ct,
 				enum ip_conntrack_info ctinfo);
-extern void ip_nat_delete_sack(struct sk_buff *skb, struct tcphdr *tcph);
+extern void ip_nat_delete_sack(struct sk_buff *skb);
 #endif

include/linux/netfilter_ipv4/ip_nat_rule.h

@@ -5,24 +5,7 @@
 #include <linux/netfilter_ipv4/ip_nat.h>
 
 #ifdef __KERNEL__
-/* Want to be told when we first NAT an expected packet for a conntrack? */
-struct ip_nat_expect
-{
-	struct list_head list;
 
-	/* Returns 1 (and sets verdict) if it has setup NAT for this
-           connection */
-	int (*expect)(struct sk_buff **pskb,
-		      unsigned int hooknum,
-		      struct ip_conntrack *ct,
-		      struct ip_nat_info *info,
-		      struct ip_conntrack *master,
-		      struct ip_nat_info *masterinfo,
-		      unsigned int *verdict);
-};
-
-extern int ip_nat_expect_register(struct ip_nat_expect *expect);
-extern void ip_nat_expect_unregister(struct ip_nat_expect *expect);
 extern int ip_nat_rule_init(void) __init;
 extern void ip_nat_rule_cleanup(void);
 extern int ip_nat_rule_find(struct sk_buff **pskb,

net/ipv4/netfilter/Makefile

@@ -9,18 +9,18 @@
 
 O_TARGET := netfilter.o
 
-export-objs = ip_conntrack_standalone.o ip_conntrack_ftp.o ip_fw_compat.o ip_nat_standalone.o ip_tables.o arp_tables.o
+export-objs = ip_conntrack_standalone.o ip_fw_compat.o ip_nat_standalone.o ip_tables.o arp_tables.o
 
 # Multipart objects.
 list-multi		:= ip_conntrack.o iptable_nat.o ipfwadm.o ipchains.o
 
 # objects for the conntrack and NAT core (used by standalone and backw. compat)
 ip_nf_conntrack-objs	:= ip_conntrack_core.o ip_conntrack_proto_generic.o ip_conntrack_proto_tcp.o ip_conntrack_proto_udp.o ip_conntrack_proto_icmp.o
-ip_nf_nat-objs		:= ip_nat_core.o ip_nat_proto_unknown.o ip_nat_proto_tcp.o ip_nat_proto_udp.o ip_nat_proto_icmp.o
+ip_nf_nat-objs		:= ip_nat_core.o ip_nat_helper.o ip_nat_proto_unknown.o ip_nat_proto_tcp.o ip_nat_proto_udp.o ip_nat_proto_icmp.o
 
 # objects for the standalone - connection tracking / NAT
 ip_conntrack-objs	:= ip_conntrack_standalone.o $(ip_nf_conntrack-objs)
-iptable_nat-objs	:= ip_nat_standalone.o ip_nat_rule.o ip_nat_helper.o $(ip_nf_nat-objs)
+iptable_nat-objs	:= ip_nat_standalone.o ip_nat_rule.o $(ip_nf_nat-objs)
 
 # objects for backwards compatibility mode
 ip_nf_compat-objs	:= ip_fw_compat.o ip_fw_compat_redir.o ip_fw_compat_masq.o $(ip_nf_conntrack-objs) $(ip_nf_nat-objs)
@@ -33,7 +33,14 @@ obj-$(CONFIG_IP_NF_CONNTRACK) += ip_conntrack.o
 
 # connection tracking helpers
 obj-$(CONFIG_IP_NF_FTP) += ip_conntrack_ftp.o
+ifdef CONFIG_IP_NF_NAT_FTP
+	export-objs += ip_conntrack_ftp.o
+endif
+
 obj-$(CONFIG_IP_NF_IRC) += ip_conntrack_irc.o
+ifdef CONFIG_IP_NF_NAT_IRC
+	export-objs += ip_conntrack_irc.o
+endif
 
 # NAT helpers 
 obj-$(CONFIG_IP_NF_NAT_FTP) += ip_nat_ftp.o

net/ipv4/netfilter/ip_conntrack_core.c

@@ -3,7 +3,12 @@
    extension. */
 
 /* (c) 1999 Paul `Rusty' Russell.  Licenced under the GNU General
-   Public Licence. */
+ * Public Licence. 
+ *
+ * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
+ * 	- new API and handling of conntrack/nat helpers
+ * 	- now capable of multiple expectations for one master
+ * */
 
 #ifdef MODULE
 #define __NO_VERSION__
@@ -38,6 +43,8 @@
 #include <linux/netfilter_ipv4/ip_conntrack_core.h>
 #include <linux/netfilter_ipv4/listhelp.h>
 
+#define IP_CONNTRACK_VERSION	"2.0"
+
 #if 0
 #define DEBUGP printk
 #else
@@ -45,6 +52,7 @@
 #endif
 
 DECLARE_RWLOCK(ip_conntrack_lock);
+DECLARE_RWLOCK(ip_conntrack_expect_tuple_lock);
 
 void (*ip_conntrack_destroyed)(struct ip_conntrack *conntrack) = NULL;
 LIST_HEAD(expect_list);
@@ -77,7 +85,7 @@ struct ip_conntrack_protocol *__find_proto(u_int8_t protocol)
 	return p;
 }
 
-struct ip_conntrack_protocol *find_proto(u_int8_t protocol)
+struct ip_conntrack_protocol *ip_ct_find_proto(u_int8_t protocol)
 {
 	struct ip_conntrack_protocol *p;
 
@@ -151,9 +159,58 @@ invert_tuple(struct ip_conntrack_tuple *inverse,
 	return protocol->invert_tuple(inverse, orig);
 }
 
+/* remove one specific expectation from all lists and free it */
+static void unexpect_related(struct ip_conntrack_expect *expect)
+{
+	MUST_BE_WRITE_LOCKED(&ip_conntrack_lock);
+	DEBUGP("unexpect_related(%p)\n", expect);
+	/* delete from global and local lists */
+	list_del(&expect->list);
+	list_del(&expect->expected_list);
+	if (!expect->sibling)
+		expect->expectant->expecting--;
+	kfree(expect);
+}
+
+/* delete all expectations for this conntrack */
+static void destroy_expectations(struct ip_conntrack *ct)
+{
+	struct list_head *exp_entry, *next;
+	struct ip_conntrack_expect *exp;
+
+	DEBUGP("destroy_expectations(%p)\n", ct);
+
+	for (exp_entry = ct->sibling_list.next;
+	     exp_entry != &ct->sibling_list; exp_entry = next) {
+		next = exp_entry->next;
+		exp = list_entry(exp_entry, struct ip_conntrack_expect,
+				 expected_list);
+
+		/* we skip established expectations, as we want to delete
+		 * the un-established ones only */
+		if (exp->sibling) {
+			DEBUGP("destroy_expectations: skipping established %p of %p\n", exp->sibling, ct);
+			continue;
+		}
+
+		IP_NF_ASSERT(list_inlist(&expect_list, exp));
+		IP_NF_ASSERT(exp->expectant == ct);
+
+		if (exp->expectant->helper->timeout
+		    && ! del_timer(&exp->timeout)) {
+		    	DEBUGP("destroy_expectations: skipping dying expectation %p of %p\n", exp, ct);
+		    	continue;
+		}
+		
+		/* delete expectation from global and private lists */
+		unexpect_related(exp);
+	}
+}
+
 static void
 clean_from_lists(struct ip_conntrack *ct)
 {
+	DEBUGP("clean_from_lists(%p)\n", ct);
 	MUST_BE_WRITE_LOCKED(&ip_conntrack_lock);
 	/* Remove from both hash lists: must not NULL out next ptrs,
            otherwise we'll look unconfirmed.  Fortunately, LIST_DELETE
@@ -164,12 +221,9 @@ clean_from_lists(struct ip_conntrack *ct)
 	LIST_DELETE(&ip_conntrack_hash
 		    [hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple)],
 		    &ct->tuplehash[IP_CT_DIR_REPLY]);
-	/* If our expected is in the list, take it out. */
-	if (ct->expected.expectant) {
-		IP_NF_ASSERT(list_inlist(&expect_list, &ct->expected));
-		IP_NF_ASSERT(ct->expected.expectant == ct);
-		LIST_DELETE(&expect_list, &ct->expected);
-	}
+
+	/* Destroy all un-established, pending expectations */
+	destroy_expectations(ct);
 }
 
 static void
@@ -178,21 +232,34 @@ destroy_conntrack(struct nf_conntrack *nfct)
 	struct ip_conntrack *ct = (struct ip_conntrack *)nfct;
 	struct ip_conntrack_protocol *proto;
 
+	DEBUGP("destroy_conntrack(%p)\n", ct);
 	IP_NF_ASSERT(atomic_read(&nfct->use) == 0);
 	IP_NF_ASSERT(!timer_pending(&ct->timeout));
 
-	if (ct->master.master)
-		nf_conntrack_put(&ct->master);
+	if (ct->master && master_ct(ct))
+		ip_conntrack_put(master_ct(ct));
 
 	/* To make sure we don't get any weird locking issues here:
 	 * destroy_conntrack() MUST NOT be called with a write lock
 	 * to ip_conntrack_lock!!! -HW */
-	proto = find_proto(ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
+	proto = ip_ct_find_proto(ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 	if (proto && proto->destroy)
 		proto->destroy(ct);
 
 	if (ip_conntrack_destroyed)
 		ip_conntrack_destroyed(ct);
+
+	WRITE_LOCK(&ip_conntrack_lock);
+	/* Delete our master expectation from the local list
+	 * and destroy it, if we've been expected */
+	if (ct->master) {
+		list_del(&ct->master->expected_list);
+		kfree(ct->master);
+	}
+	WRITE_UNLOCK(&ip_conntrack_lock);
+
+	
+	DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 	kmem_cache_free(ip_conntrack_cachep, ct);
 	atomic_dec(&ip_conntrack_count);
 }
@@ -390,7 +457,7 @@ icmp_error_track(struct sk_buff *skb,
 		return NULL;
 	}
 
-	innerproto = find_proto(inner->protocol);
+	innerproto = ip_ct_find_proto(inner->protocol);
 	/* Are they talking about one of our connections? */
 	if (inner->ihl * 4 + 8 > datalen
 	    || !get_tuple(inner, datalen, &origtuple, innerproto)) {
@@ -470,10 +537,18 @@ static inline int helper_cmp(const struct ip_conntrack_helper *i,
 	return ip_ct_tuple_mask_cmp(rtuple, &i->tuple, &i->mask);
 }
 
+struct ip_conntrack_helper *ip_ct_find_helper(const struct ip_conntrack_tuple *tuple)
+{
+	return LIST_FIND(&helpers, helper_cmp,
+			 struct ip_conntrack_helper *,
+			 tuple);
+}
+
 /* Compare parts depending on mask. */
 static inline int expect_cmp(const struct ip_conntrack_expect *i,
 			     const struct ip_conntrack_tuple *tuple)
 {
+	MUST_BE_READ_LOCKED(&ip_conntrack_expect_tuple_lock);
 	return ip_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask);
 }
 
@@ -522,7 +597,7 @@ init_conntrack(const struct ip_conntrack_tuple *tuple,
 		return ERR_PTR(-ENOMEM);
 	}
 
-	memset(conntrack, 0, sizeof(struct ip_conntrack));
+	memset(conntrack, 0, sizeof(*conntrack));
 	atomic_set(&conntrack->ct_general.use, 1);
 	conntrack->ct_general.destroy = destroy_conntrack;
 	conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *tuple;
@@ -541,31 +616,44 @@ init_conntrack(const struct ip_conntrack_tuple *tuple,
 	conntrack->timeout.data = (unsigned long)conntrack;
 	conntrack->timeout.function = death_by_timeout;
 
+	INIT_LIST_HEAD(&conntrack->sibling_list);
+
 	/* Mark clearly that it's not in the hash table. */
 	conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list.next = NULL;
 
-	/* Write lock required for deletion of expected.  Without
-           this, a read-lock would do. */
 	WRITE_LOCK(&ip_conntrack_lock);
-	conntrack->helper = LIST_FIND(&helpers, helper_cmp,
-				      struct ip_conntrack_helper *,
-				      &repl_tuple);
 	/* Need finding and deleting of expected ONLY if we win race */
+	READ_LOCK(&ip_conntrack_expect_tuple_lock);
 	expected = LIST_FIND(&expect_list, expect_cmp,
 			     struct ip_conntrack_expect *, tuple);
+	READ_UNLOCK(&ip_conntrack_expect_tuple_lock);
+
+	/* Look up the conntrack helper for master connections only */
+	if (!expected)
+		conntrack->helper = ip_ct_find_helper(&repl_tuple);
+
+	/* If the expectation is dying, then this is a looser. */
+	if (expected
+	    && expected->expectant->helper->timeout
+	    && ! del_timer(&expected->timeout))
+		expected = NULL;
+
 	/* If master is not in hash table yet (ie. packet hasn't left
 	   this machine yet), how can other end know about expected?
 	   Hence these are not the droids you are looking for (if
 	   master ct never got confirmed, we'd hold a reference to it
 	   and weird things would happen to future packets). */
 	if (expected && is_confirmed(expected->expectant)) {
+		DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
+			conntrack, expected);
 		/* Welcome, Mr. Bond.  We've been expecting you... */
+		IP_NF_ASSERT(master_ct(conntrack));
 		conntrack->status = IPS_EXPECTED;
-		conntrack->master.master = &expected->expectant->ct_general;
-		IP_NF_ASSERT(conntrack->master.master);
+		conntrack->master = expected;
+		expected->sibling = conntrack;
 		LIST_DELETE(&expect_list, expected);
-		expected->expectant = NULL;
-		nf_conntrack_get(&conntrack->master);
+		expected->expectant->expecting--;
+		nf_conntrack_get(&master_ct(conntrack)->infos[0]);
 	}
 	atomic_inc(&ip_conntrack_count);
 	WRITE_UNLOCK(&ip_conntrack_lock);
@@ -670,7 +758,7 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
 			return NF_STOLEN;
 	}
 
-	proto = find_proto((*pskb)->nh.iph->protocol);
+	proto = ip_ct_find_proto((*pskb)->nh.iph->protocol);
 
 	/* It may be an icmp error... */
 	if ((*pskb)->nh.iph->protocol == IPPROTO_ICMP 
@@ -714,64 +802,208 @@ unsigned int ip_conntrack_in(unsigned int hooknum,
 int invert_tuplepr(struct ip_conntrack_tuple *inverse,
 		   const struct ip_conntrack_tuple *orig)
 {
-	return invert_tuple(inverse, orig, find_proto(orig->dst.protonum));
+	return invert_tuple(inverse, orig, ip_ct_find_proto(orig->dst.protonum));
 }
 
-static void unexpect_related(struct ip_conntrack *related_to)
+static inline int resent_expect(const struct ip_conntrack_expect *i,
+			        const struct ip_conntrack_tuple *tuple,
+			        const struct ip_conntrack_tuple *mask)
 {
-	MUST_BE_WRITE_LOCKED(&ip_conntrack_lock);
-	list_del(&related_to->expected.list);
-	related_to->expected.expectant = NULL;
+	DEBUGP("resent_expect\n");
+	DEBUGP("   tuple:   "); DUMP_TUPLE(&i->tuple);
+	DEBUGP("ct_tuple:   "); DUMP_TUPLE(&i->ct_tuple);
+	DEBUGP("test tuple: "); DUMP_TUPLE(tuple);
+	return (((i->ct_tuple.dst.protonum == 0 && ip_ct_tuple_equal(&i->tuple, tuple))
+	         || (i->ct_tuple.dst.protonum && ip_ct_tuple_equal(&i->ct_tuple, tuple)))
+		&& ip_ct_tuple_equal(&i->mask, mask));
 }
 
 /* Would two expected things clash? */
 static inline int expect_clash(const struct ip_conntrack_expect *i,
-			       const struct ip_conntrack_expect *new)
+			       const struct ip_conntrack_tuple *tuple,
+			       const struct ip_conntrack_tuple *mask)
 {
 	/* Part covered by intersection of masks must be unequal,
            otherwise they clash */
 	struct ip_conntrack_tuple intersect_mask
-		= { { i->mask.src.ip & new->mask.src.ip,
-		      { i->mask.src.u.all & new->mask.src.u.all } },
-		    { i->mask.dst.ip & new->mask.dst.ip,
-		      { i->mask.dst.u.all & new->mask.dst.u.all },
-		      i->mask.dst.protonum & new->mask.dst.protonum } };
+		= { { i->mask.src.ip & mask->src.ip,
+		      { i->mask.src.u.all & mask->src.u.all } },
+		    { i->mask.dst.ip & mask->dst.ip,
+		      { i->mask.dst.u.all & mask->dst.u.all },
+		      i->mask.dst.protonum & mask->dst.protonum } };
 
-	return ip_ct_tuple_mask_cmp(&i->tuple, &new->tuple, &intersect_mask);
+	return ip_ct_tuple_mask_cmp(&i->tuple, tuple, &intersect_mask);
 }
 
-/* Add a related connection. */
-int ip_conntrack_expect_related(struct ip_conntrack *related_to,
-				const struct ip_conntrack_tuple *tuple,
-				const struct ip_conntrack_tuple *mask,
-				int (*expectfn)(struct ip_conntrack *))
+void ip_conntrack_unexpect_related(struct ip_conntrack_expect *expect)
 {
 	WRITE_LOCK(&ip_conntrack_lock);
-	if (related_to->expected.expectant)
-		unexpect_related(related_to);
+	unexpect_related(expect);
+	WRITE_UNLOCK(&ip_conntrack_lock);
+}
+	
+static void expectation_timed_out(unsigned long ul_expect)
+{
+	struct ip_conntrack_expect *expect = (void *) ul_expect;
+
+	DEBUGP("expectation %p timed out\n", expect);	
+	ip_conntrack_unexpect_related(expect);
+}
 
-	related_to->expected.tuple = *tuple;
-	related_to->expected.mask = *mask;
-	related_to->expected.expectfn = expectfn;
+/* Add a related connection. */
+int ip_conntrack_expect_related(struct ip_conntrack *related_to,
+				struct ip_conntrack_expect *expect)
+{
+	struct ip_conntrack_expect *new;
+	int ret = 0;
 
-	if (LIST_FIND(&expect_list, expect_clash,
-		      struct ip_conntrack_expect *, &related_to->expected)) {
+	WRITE_LOCK(&ip_conntrack_lock);
+	/* Because of the write lock, no reader can walk the lists,
+	 * so there is no need to use the tuple lock too */
+
+	DEBUGP("ip_conntrack_expect_related %p\n", related_to);
+	DEBUGP("tuple: "); DUMP_TUPLE(&expect->tuple);
+	DEBUGP("mask:  "); DUMP_TUPLE(&expect->mask);
+
+	new = LIST_FIND(&expect_list, resent_expect,
+		        struct ip_conntrack_expect *, &expect->tuple, &expect->mask);
+	if (new) {
+		/* Helper private data may contain offsets but no pointers
+		   pointing into the payload - otherwise we should have to copy 
+		   the data filled out by the helper over the old one */
+		DEBUGP("expect_related: resent packet\n");
+		if (related_to->helper->timeout) {
+			/* Refresh timer, if possible... */
+			if (del_timer(&new->timeout)) {
+				new->timeout.expires = jiffies + related_to->helper->timeout * HZ;
+				add_timer(&new->timeout);
+				WRITE_UNLOCK(&ip_conntrack_lock);
+				return -EEXIST;
+			}
+			/* ... otherwise expectation is dying. Fall over and create a new one. */
+			new = NULL;
+		} else {
+			WRITE_UNLOCK(&ip_conntrack_lock);
+			return -EEXIST;
+		}
+	} else if (related_to->helper->max_expected
+	    	   && related_to->expecting >= related_to->helper->max_expected) {
+	    	if (net_ratelimit())
+		    	printk(KERN_WARNING 
+		    	       "ip_conntrack: max number of expected connections %i of %s reached for %u.%u.%u.%u->%u.%u.%u.%u%s\n",
+		    	       related_to->helper->max_expected, 
+		    	       related_to->helper->name,
+		    	       NIPQUAD(related_to->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip),
+		    	       NIPQUAD(related_to->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip),
+		    	       related_to->helper->flags & IP_CT_HELPER_F_REUSE_EXPECT ?
+		    	       ", reusing" : "");
+	    	if (related_to->helper->flags & IP_CT_HELPER_F_REUSE_EXPECT) {
+		    	struct list_head *cur_item;
+
+		    	/* Let's choose the the oldest expectation to overwrite */
+			list_for_each(cur_item, &related_to->sibling_list) { 
+				new = list_entry(cur_item, struct ip_conntrack_expect,
+						 expected_list);
+				if (new->sibling == NULL)
+					break;
+			}
+			IP_NF_ASSERT(new);
+			if (related_to->helper->timeout 
+			    &&  !del_timer(&new->timeout)) {
+				/* Expectation is dying. Fall over and create a new one */
+				new = NULL;
+			} else {
+				list_del(&new->list);
+				list_del(&new->expected_list);
+				related_to->expecting--;
+				ret = -EPERM;
+			}
+		} else {
 			WRITE_UNLOCK(&ip_conntrack_lock);
+			return -EPERM;
+		}
+	} else if (LIST_FIND(&expect_list, expect_clash,
+		      struct ip_conntrack_expect *, &expect->tuple, &expect->mask)) {
+		WRITE_UNLOCK(&ip_conntrack_lock);
+		DEBUGP("expect_related: busy!\n");
 		return -EBUSY;
 	}
 	
-	list_prepend(&expect_list, &related_to->expected);
-	related_to->expected.expectant = related_to;
+	if (!new) {
+		new = (struct ip_conntrack_expect *) 
+		      kmalloc(sizeof(*expect), GFP_ATOMIC);
+		if (!new) {
 			WRITE_UNLOCK(&ip_conntrack_lock);
+			DEBUGP("expect_relaed: OOM allocating expect\n");
+			return -ENOMEM;
+		}
+	}
 	
-	return 0;
+	/* Zero out the new structure, then fill out it with the data */
+	DEBUGP("new expectation %p of conntrack %p\n", new, related_to);
+	memset(new, 0, sizeof(*expect));
+	INIT_LIST_HEAD(&new->list);
+	INIT_LIST_HEAD(&new->expected_list);
+	memcpy(new, expect, sizeof(*expect));
+	new->expectant = related_to;
+	new->sibling = NULL;
+	
+	/* add to expected list for this connection */	
+	list_add(&new->expected_list, &related_to->sibling_list);
+	/* add to global list of expectations */
+	list_prepend(&expect_list, &new->list);
+	/* add and start timer if required */
+	if (related_to->helper->timeout) {
+		init_timer(&new->timeout);
+		new->timeout.data = (unsigned long)new;
+		new->timeout.function = expectation_timed_out;
+		new->timeout.expires = jiffies + related_to->helper->timeout * HZ;
+		add_timer(&new->timeout);
+	}
+	related_to->expecting++;
+
+	WRITE_UNLOCK(&ip_conntrack_lock);
+
+	return ret;
 }
 
-void ip_conntrack_unexpect_related(struct ip_conntrack *related_to)
+/* Change tuple in an existing expectation */
+int ip_conntrack_change_expect(struct ip_conntrack_expect *expect,
+			       struct ip_conntrack_tuple *newtuple)
 {
-	WRITE_LOCK(&ip_conntrack_lock);
-	unexpect_related(related_to);
-	WRITE_UNLOCK(&ip_conntrack_lock);
+	MUST_BE_READ_LOCKED(&ip_conntrack_lock);
+
+	DEBUGP("change_expect:\n");
+	DEBUGP("exp tuple: "); DUMP_TUPLE(&expect->tuple);
+	DEBUGP("exp mask:  "); DUMP_TUPLE(&expect->mask);
+	DEBUGP("newtuple:  "); DUMP_TUPLE(newtuple);
+	if (expect->ct_tuple.dst.protonum == 0) {
+		/* Never seen before */
+		DEBUGP("change expect: never seen before\n");
+		if (!ip_ct_tuple_equal(&expect->tuple, newtuple) 
+		    && LIST_FIND(&expect_list, expect_clash,
+			         struct ip_conntrack_expect *, newtuple, &expect->mask)) {
+			/* Force NAT to find an unused tuple */
+			return -1;
+		} else {
+			WRITE_LOCK(&ip_conntrack_expect_tuple_lock);
+			memcpy(&expect->ct_tuple, &expect->tuple, sizeof(expect->tuple));
+			memcpy(&expect->tuple, newtuple, sizeof(expect->tuple));
+			WRITE_UNLOCK(&ip_conntrack_expect_tuple_lock);
+			return 0;
+		}
+	} else {
+		/* Resent packet */
+		DEBUGP("change expect: resent packet\n");
+		if (ip_ct_tuple_equal(&expect->tuple, newtuple)) {
+			return 0;
+		} else {
+			/* Force NAT to choose again the same port */
+			return -1;
+		}
+	}
+	
+	return -1;
 }
 
 /* Alter reply tuple (maybe alter helper).  If it's already taken,
@@ -791,10 +1023,12 @@ int ip_conntrack_alter_reply(struct ip_conntrack *conntrack,
 	DUMP_TUPLE(newreply);
 
 	conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
+	if (!conntrack->master)
 		conntrack->helper = LIST_FIND(&helpers, helper_cmp,
 					      struct ip_conntrack_helper *,
 					      newreply);
 	WRITE_UNLOCK(&ip_conntrack_lock);
+
 	return 1;
 }
 
@@ -813,14 +1047,10 @@ static inline int unhelp(struct ip_conntrack_tuple_hash *i,
 			 const struct ip_conntrack_helper *me)
 {
 	if (i->ctrack->helper == me) {
-		i->ctrack->helper = NULL;
 		/* Get rid of any expected. */
-		if (i->ctrack->expected.expectant) {
-			IP_NF_ASSERT(i->ctrack->expected.expectant
-				     == i->ctrack);
-			LIST_DELETE(&expect_list, &i->ctrack->expected);
-			i->ctrack->expected.expectant = NULL;
-		}
+		destroy_expectations(i->ctrack);
+		/* And *then* set helper to NULL */
+		i->ctrack->helper = NULL;
 	}
 	return 0;
 }
@@ -1104,8 +1334,10 @@ int __init ip_conntrack_init(void)
 	}
 	ip_conntrack_max = 8 * ip_conntrack_htable_size;
 
-	printk("ip_conntrack (%u buckets, %d max)\n",
-	       ip_conntrack_htable_size, ip_conntrack_max);
+	printk("ip_conntrack version %s (%u buckets, %d max)"
+	       " - %d bytes per conntrack\n", IP_CONNTRACK_VERSION,
+	       ip_conntrack_htable_size, ip_conntrack_max,
+	       sizeof(struct ip_conntrack));
 
 	ret = nf_register_sockopt(&so_getorigdst);
 	if (ret != 0)

net/ipv4/netfilter/ip_conntrack_ftp.c

 /* FTP extension for IP connection tracking. */
+#include <linux/config.h>
 #include <linux/module.h>
 #include <linux/netfilter.h>
 #include <linux/ip.h>
@@ -242,8 +243,10 @@ static int help(const struct iphdr *iph, size_t len,
 	u_int32_t array[6] = { 0 };
 	int dir = CTINFO2DIR(ctinfo);
 	unsigned int matchlen, matchoff;
-	struct ip_conntrack_tuple t, mask;
-	struct ip_ct_ftp *info = &ct->help.ct_ftp_info;
+	struct ip_ct_ftp_master *ct_ftp_info = &ct->help.ct_ftp_info;
+	struct ip_conntrack_expect expect, *exp = &expect;
+	struct ip_ct_ftp_expect *exp_ftp_info = &exp->help.exp_ftp_info;
+
 	unsigned int i;
 	int found = 0;
 
@@ -271,8 +274,8 @@ static int help(const struct iphdr *iph, size_t len,
 	}
 
 	LOCK_BH(&ip_ftp_lock);
-	old_seq_aft_nl_set = info->seq_aft_nl_set[dir];
-	old_seq_aft_nl = info->seq_aft_nl[dir];
+	old_seq_aft_nl_set = ct_ftp_info->seq_aft_nl_set[dir];
+	old_seq_aft_nl = ct_ftp_info->seq_aft_nl[dir];
 
 	DEBUGP("conntrack_ftp: datalen %u\n", datalen);
 	if ((datalen > 0) && (data[datalen-1] == '\n')) {
@@ -281,8 +284,9 @@ static int help(const struct iphdr *iph, size_t len,
 		    || after(ntohl(tcph->seq) + datalen, old_seq_aft_nl)) {
 			DEBUGP("conntrack_ftp: updating nl to %u\n",
 			       ntohl(tcph->seq) + datalen);
-			info->seq_aft_nl[dir] = ntohl(tcph->seq) + datalen;
-			info->seq_aft_nl_set[dir] = 1;
+			ct_ftp_info->seq_aft_nl[dir] = 
+						ntohl(tcph->seq) + datalen;
+			ct_ftp_info->seq_aft_nl_set[dir] = 1;
 		}
 	}
 	UNLOCK_BH(&ip_ftp_lock);
@@ -331,15 +335,16 @@ static int help(const struct iphdr *iph, size_t len,
 	       (int)matchlen, data + matchoff,
 	       matchlen, ntohl(tcph->seq) + matchoff);
 	       
+	memset(&expect, 0, sizeof(expect));
+
 	/* Update the ftp info */
 	LOCK_BH(&ip_ftp_lock);
 	if (htonl((array[0] << 24) | (array[1] << 16) | (array[2] << 8) | array[3])
 	    == ct->tuplehash[dir].tuple.src.ip) {
-		info->is_ftp = 21;
-		info->seq = ntohl(tcph->seq) + matchoff;
-		info->len = matchlen;
-		info->ftptype = search[i].ftptype;
-		info->port = array[4] << 8 | array[5];
+		exp->seq = ntohl(tcph->seq) + matchoff;
+		exp_ftp_info->len = matchlen;
+		exp_ftp_info->ftptype = search[i].ftptype;
+		exp_ftp_info->port = array[4] << 8 | array[5];
 	} else {
 		/* Enrico Scholz's passive FTP to partially RNAT'd ftp
 		   server: it really wants us to connect to a
@@ -356,18 +361,21 @@ static int help(const struct iphdr *iph, size_t len,
 		if (!loose) goto out;
 	}
 
-	t = ((struct ip_conntrack_tuple)
+	exp->tuple = ((struct ip_conntrack_tuple)
 		{ { ct->tuplehash[!dir].tuple.src.ip,
 		    { 0 } },
 		  { htonl((array[0] << 24) | (array[1] << 16)
 			  | (array[2] << 8) | array[3]),
 		    { htons(array[4] << 8 | array[5]) },
 		    IPPROTO_TCP }});
-	mask = ((struct ip_conntrack_tuple)
+	exp->mask = ((struct ip_conntrack_tuple)
 		{ { 0xFFFFFFFF, { 0 } },
 		  { 0xFFFFFFFF, { 0xFFFF }, 0xFFFF }});
+
+	exp->expectfn = NULL;
+
 	/* Ignore failure; should only happen with NAT */
-	ip_conntrack_expect_related(ct, &t, &mask, NULL);
+	ip_conntrack_expect_related(ct, &expect);
  out:
 	UNLOCK_BH(&ip_ftp_lock);
 
@@ -375,6 +383,7 @@ static int help(const struct iphdr *iph, size_t len,
 }
 
 static struct ip_conntrack_helper ftp[MAX_PORTS];
+static char ftp_names[MAX_PORTS][10];
 
 /* Not __exit: called from init() */
 static void fini(void)
@@ -390,9 +399,10 @@ static void fini(void)
 static int __init init(void)
 {
 	int i, ret;
+	char *tmpname;
 
 	if (ports[0] == 0)
-		ports[0] = 21;
+		ports[0] = FTP_PORT;
 
 	for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 		memset(&ftp[i], 0, sizeof(struct ip_conntrack_helper));
@@ -400,7 +410,19 @@ static int __init init(void)
 		ftp[i].tuple.dst.protonum = IPPROTO_TCP;
 		ftp[i].mask.src.u.tcp.port = 0xFFFF;
 		ftp[i].mask.dst.protonum = 0xFFFF;
+		ftp[i].max_expected = 1;
+		ftp[i].timeout = 0;
+		ftp[i].flags = IP_CT_HELPER_F_REUSE_EXPECT;
+		ftp[i].me = ip_conntrack_ftp;
 		ftp[i].help = help;
+
+		tmpname = &ftp_names[i][0];
+		if (ports[i] == FTP_PORT)
+			sprintf(tmpname, "ftp");
+		else
+			sprintf(tmpname, "ftp-%d", ports[i]);
+		ftp[i].name = tmpname;
+
 		DEBUGP("ip_ct_ftp: registering helper for port %d\n", 
 				ports[i]);
 		ret = ip_conntrack_helper_register(&ftp[i]);
@@ -414,10 +436,10 @@ static int __init init(void)
 	return 0;
 }
 
-
+#ifdef CONFIG_IP_NF_NAT_NEEDED
 EXPORT_SYMBOL(ip_ftp_lock);
-EXPORT_SYMBOL(ip_conntrack_ftp);
-MODULE_LICENSE("GPL");
+#endif
 
+MODULE_LICENSE("GPL");
 module_init(init);
 module_exit(fini);

net/ipv4/netfilter/ip_conntrack_irc.c

@@ -11,12 +11,18 @@
  **
  *	Module load syntax:
  * 	insmod ip_conntrack_irc.o ports=port1,port2,...port<MAX_PORTS>
+ *			    max_dcc_channels=n dcc_timeout=secs
  *	
  * 	please give the ports of all IRC servers You wish to connect to.
- *	If You don't specify ports, the default will be port 6667
+ *	If You don't specify ports, the default will be port 6667.
+ *	With max_dcc_channels you can define the maximum number of not
+ *	yet answered DCC channels per IRC session (default 8).
+ *	With dcc_timeout you can specify how long the system waits for 
+ *	an expected DCC channel (default 300 seconds).
  *
  */
 
+#include <linux/config.h>
 #include <linux/module.h>
 #include <linux/netfilter.h>
 #include <linux/ip.h>
@@ -30,6 +36,8 @@
 #define MAX_PORTS 8
 static int ports[MAX_PORTS];
 static int ports_n_c = 0;
+static int max_dcc_channels = 8;
+static unsigned int dcc_timeout = 300;
 
 MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
 MODULE_DESCRIPTION("IRC (DCC) connection tracking module");
@@ -37,6 +45,10 @@ MODULE_LICENSE("GPL");
 #ifdef MODULE_PARM
 MODULE_PARM(ports, "1-" __MODULE_STRING(MAX_PORTS) "i");
 MODULE_PARM_DESC(ports, "port numbers of IRC servers");
+MODULE_PARM(max_dcc_channels, "i");
+MODULE_PARM_DESC(max_dcc_channels, "max number of expected DCC channels per IRC session");
+MODULE_PARM(dcc_timeout, "i");
+MODULE_PARM_DESC(dcc_timeout, "timeout on for unestablished DCC channels");
 #endif
 
 #define NUM_DCCPROTO 	5
@@ -103,23 +115,15 @@ static int help(const struct iphdr *iph, size_t len,
 	u_int32_t tcplen = len - iph->ihl * 4;
 	u_int32_t datalen = tcplen - tcph->doff * 4;
 	int dir = CTINFO2DIR(ctinfo);
-	struct ip_conntrack_tuple t, mask;
+	struct ip_conntrack_expect expect, *exp = &expect;
+	struct ip_ct_irc_expect *exp_irc_info = &exp->help.exp_irc_info;
 
 	u_int32_t dcc_ip;
 	u_int16_t dcc_port;
 	int i;
 	char *addr_beg_p, *addr_end_p;
 
-	struct ip_ct_irc *info = &ct->help.ct_irc_info;
-
-	mask = ((struct ip_conntrack_tuple)
-		{ { 0, { 0 } },
-		  { 0xFFFFFFFF, { 0xFFFF }, 0xFFFF }});
-
 	DEBUGP("entered\n");
-	/* Can't track connections formed before we registered */
-	if (!info)
-		return NF_ACCEPT;
 
 	/* If packet is coming from IRC server */
 	if (dir == IP_CT_DIR_REPLY)
@@ -190,32 +194,36 @@ static int help(const struct iphdr *iph, size_t len,
 				continue;
 			}
 			
+			memset(&expect, 0, sizeof(expect));
+
 			LOCK_BH(&ip_irc_lock);
 
 			/* save position of address in dcc string,
 			 * neccessary for NAT */
-			info->is_irc = IP_CONNTR_IRC;
 			DEBUGP("tcph->seq = %u\n", tcph->seq);
-			info->seq = ntohl(tcph->seq) + (addr_beg_p - _data);
-			info->len = (addr_end_p - addr_beg_p);
-			info->port = dcc_port;
+			exp->seq = ntohl(tcph->seq) + (addr_beg_p - _data);
+			exp_irc_info->len = (addr_end_p - addr_beg_p);
+			exp_irc_info->port = dcc_port;
 			DEBUGP("wrote info seq=%u (ofs=%u), len=%d\n",
-				info->seq, (addr_end_p - _data), info->len);
+				exp->seq, (addr_end_p - _data), exp_irc_info->len);
 
-			memset(&t, 0, sizeof(t));
-			t.src.ip = 0;
-			t.src.u.tcp.port = 0;
-			t.dst.ip = htonl(dcc_ip);
-			t.dst.u.tcp.port = htons(info->port);
-			t.dst.protonum = IPPROTO_TCP;
+			exp->tuple = ((struct ip_conntrack_tuple)
+				{ { 0, { 0 } },
+				  { htonl(dcc_ip), { htons(dcc_port) },
+				    IPPROTO_TCP }});
+			exp->mask = ((struct ip_conntrack_tuple)
+				{ { 0, { 0 } },
+				  { 0xFFFFFFFF, { 0xFFFF }, 0xFFFF }});
+
+			exp->expectfn = NULL;
 
 			DEBUGP("expect_related %u.%u.%u.%u:%u-%u.%u.%u.%u:%u\n",
-				NIPQUAD(t.src.ip),
-				ntohs(t.src.u.tcp.port),
-				NIPQUAD(t.dst.ip),
-				ntohs(t.dst.u.tcp.port));
+				NIPQUAD(exp->tuple.src.ip),
+				ntohs(exp->tuple.src.u.tcp.port),
+				NIPQUAD(exp->tuple.dst.ip),
+				ntohs(exp->tuple.dst.u.tcp.port));
 
-			ip_conntrack_expect_related(ct, &t, &mask, NULL);
+			ip_conntrack_expect_related(ct, &expect);
 			UNLOCK_BH(&ip_irc_lock);
 
 			return NF_ACCEPT;
@@ -226,29 +234,53 @@ static int help(const struct iphdr *iph, size_t len,
 }
 
 static struct ip_conntrack_helper irc_helpers[MAX_PORTS];
+static char irc_names[MAX_PORTS][10];
 
 static void fini(void);
 
 static int __init init(void)
 {
 	int i, ret;
+	struct ip_conntrack_helper *hlpr;
+	char *tmpname;
+
+	if (max_dcc_channels < 1) {
+		printk("ip_conntrack_irc: max_dcc_channels must be a positive integer\n");
+		return -EBUSY;
+	}
+	if (dcc_timeout < 0) {
+		printk("ip_conntrack_irc: dcc_timeout must be a positive integer\n");
+		return -EBUSY;
+	}
 	
 	/* If no port given, default to standard irc port */
 	if (ports[0] == 0)
-		ports[0] = 6667;
+		ports[0] = IRC_PORT;
 
 	for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
-		memset(&irc_helpers[i], 0,
+		hlpr = &irc_helpers[i];
+		memset(hlpr, 0,
 		       sizeof(struct ip_conntrack_helper));
-		irc_helpers[i].tuple.src.u.tcp.port = htons(ports[i]);
-		irc_helpers[i].tuple.dst.protonum = IPPROTO_TCP;
-		irc_helpers[i].mask.src.u.tcp.port = 0xFFFF;
-		irc_helpers[i].mask.dst.protonum = 0xFFFF;
-		irc_helpers[i].help = help;
+		hlpr->tuple.src.u.tcp.port = htons(ports[i]);
+		hlpr->tuple.dst.protonum = IPPROTO_TCP;
+		hlpr->mask.src.u.tcp.port = 0xFFFF;
+		hlpr->mask.dst.protonum = 0xFFFF;
+		hlpr->max_expected = max_dcc_channels;
+		hlpr->timeout = dcc_timeout;
+		hlpr->flags = IP_CT_HELPER_F_REUSE_EXPECT;
+		hlpr->me = ip_conntrack_irc;
+		hlpr->help = help;
+
+		tmpname = &irc_names[i][0];
+		if (ports[i] == IRC_PORT)
+			sprintf(tmpname, "irc");
+		else
+			sprintf(tmpname, "irc-%d", i);
+		hlpr->name = tmpname;
 
 		DEBUGP("port #%d: %d\n", i, ports[i]);
 
-		ret = ip_conntrack_helper_register(&irc_helpers[i]);
+		ret = ip_conntrack_helper_register(hlpr);
 
 		if (ret) {
 			printk("ip_conntrack_irc: ERROR registering port %d\n",
@@ -273,5 +305,9 @@ static void fini(void)
 	}
 }
 
+#ifdef CONFIG_IP_NF_NAT_NEEDED
+EXPORT_SYMBOL(ip_irc_lock);
+#endif
+
 module_init(init);
 module_exit(fini);

net/ipv4/netfilter/ip_conntrack_proto_generic.c

@@ -57,5 +57,5 @@ new(struct ip_conntrack *conntrack, struct iphdr *iph, size_t len)
 struct ip_conntrack_protocol ip_conntrack_generic_protocol
 = { { NULL, NULL }, 0, "unknown",
     generic_pkt_to_tuple, generic_invert_tuple, generic_print_tuple,
-    generic_print_conntrack, established, new, NULL, NULL };
+    generic_print_conntrack, established, new, NULL, NULL, NULL };
 

net/ipv4/netfilter/ip_conntrack_proto_icmp.c

@@ -113,4 +113,4 @@ static int icmp_new(struct ip_conntrack *conntrack,
 struct ip_conntrack_protocol ip_conntrack_protocol_icmp
 = { { NULL, NULL }, IPPROTO_ICMP, "icmp",
     icmp_pkt_to_tuple, icmp_invert_tuple, icmp_print_tuple,
-    icmp_print_conntrack, icmp_packet, icmp_new, NULL, NULL };
+    icmp_print_conntrack, icmp_packet, icmp_new, NULL, NULL, NULL };

net/ipv4/netfilter/ip_conntrack_proto_tcp.c

@@ -7,6 +7,9 @@
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/tcp.h>
+
+#include <net/tcp.h>
+
 #include <linux/netfilter_ipv4/ip_conntrack.h>
 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
 #include <linux/netfilter_ipv4/lockhelp.h>
@@ -227,7 +230,19 @@ static int tcp_new(struct ip_conntrack *conntrack,
 	return 1;
 }
 
+static int tcp_exp_matches_pkt(struct ip_conntrack_expect *exp,
+			       struct sk_buff **pskb)
+{
+	struct iphdr *iph = (*pskb)->nh.iph;
+	struct tcphdr *tcph = (struct tcphdr *)((u_int32_t *)iph + iph->ihl);
+	unsigned int datalen;
+
+	datalen = (*pskb)->len - iph->ihl*4 - tcph->doff*4;
+
+	return between(exp->seq, ntohl(tcph->seq), ntohl(tcph->seq) + datalen);
+}
+
 struct ip_conntrack_protocol ip_conntrack_protocol_tcp
 = { { NULL, NULL }, IPPROTO_TCP, "tcp",
     tcp_pkt_to_tuple, tcp_invert_tuple, tcp_print_tuple, tcp_print_conntrack,
-    tcp_packet, tcp_new, NULL, NULL };
+    tcp_packet, tcp_new, NULL, tcp_exp_matches_pkt, NULL };

net/ipv4/netfilter/ip_conntrack_proto_udp.c

@@ -71,4 +71,4 @@ static int udp_new(struct ip_conntrack *conntrack,
 struct ip_conntrack_protocol ip_conntrack_protocol_udp
 = { { NULL, NULL }, IPPROTO_UDP, "udp",
     udp_pkt_to_tuple, udp_invert_tuple, udp_print_tuple, udp_print_conntrack,
-    udp_packet, udp_new, NULL, NULL };
+    udp_packet, udp_new, NULL, NULL, NULL };

net/ipv4/netfilter/ip_conntrack_standalone.c

@@ -62,7 +62,13 @@ print_expect(char *buffer, const struct ip_conntrack_expect *expect)
 {
 	unsigned int len;
 
-	len = sprintf(buffer, "EXPECTING: proto=%u ",
+	if (expect->expectant->helper->timeout)
+		len = sprintf(buffer, "EXPECTING: %lu ",
+			      timer_pending(&expect->timeout)
+			      ? (expect->timeout.expires - jiffies)/HZ : 0);
+	else
+		len = sprintf(buffer, "EXPECTING: - ");
+	len += sprintf(buffer + len, "proto=%u ",
 		      expect->tuple.dst.protonum);
 	len += print_tuple(buffer + len, &expect->tuple,
 			   __find_proto(expect->tuple.dst.protonum));
@@ -314,7 +320,7 @@ void ip_conntrack_protocol_unregister(struct ip_conntrack_protocol *proto)
 {
 	WRITE_LOCK(&ip_conntrack_lock);
 
-	/* find_proto() returns proto_generic in case there is no protocol 
+	/* ip_ct_find_proto() returns proto_generic in case there is no protocol 
 	 * helper. So this should be enough - HW */
 	LIST_DELETE(&protocol_list, proto);
 	WRITE_UNLOCK(&ip_conntrack_lock);
@@ -353,8 +359,12 @@ EXPORT_SYMBOL(ip_conntrack_helper_register);
 EXPORT_SYMBOL(ip_conntrack_helper_unregister);
 EXPORT_SYMBOL(ip_ct_selective_cleanup);
 EXPORT_SYMBOL(ip_ct_refresh);
+EXPORT_SYMBOL(ip_ct_find_proto);
+EXPORT_SYMBOL(ip_ct_find_helper);
 EXPORT_SYMBOL(ip_conntrack_expect_related);
+EXPORT_SYMBOL(ip_conntrack_change_expect);
 EXPORT_SYMBOL(ip_conntrack_unexpect_related);
 EXPORT_SYMBOL(ip_conntrack_tuple_taken);
 EXPORT_SYMBOL(ip_ct_gather_frags);
 EXPORT_SYMBOL(ip_conntrack_htable_size);
+EXPORT_SYMBOL(ip_conntrack_lock);

net/ipv4/netfilter/ip_fw_compat_masq.c

@@ -130,7 +130,7 @@ check_for_demasq(struct sk_buff **pskb)
 	struct ip_conntrack *ct;
 	int ret;
 
-	protocol = find_proto(iph->protocol);
+	protocol = ip_ct_find_proto(iph->protocol);
 
 	/* We don't feed packets to conntrack system unless we know
            they're part of an connection already established by an

net/ipv4/netfilter/ip_nat_core.c

@@ -21,10 +21,14 @@
 #define ASSERT_READ_LOCK(x) MUST_BE_READ_LOCKED(&ip_nat_lock)
 #define ASSERT_WRITE_LOCK(x) MUST_BE_WRITE_LOCKED(&ip_nat_lock)
 
+#include <linux/netfilter_ipv4/ip_conntrack.h>
+#include <linux/netfilter_ipv4/ip_conntrack_core.h>
+#include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
 #include <linux/netfilter_ipv4/ip_nat.h>
 #include <linux/netfilter_ipv4/ip_nat_protocol.h>
 #include <linux/netfilter_ipv4/ip_nat_core.h>
 #include <linux/netfilter_ipv4/ip_nat_helper.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
 #include <linux/netfilter_ipv4/listhelp.h>
 
 #if 0
@@ -34,6 +38,7 @@
 #endif
 
 DECLARE_RWLOCK(ip_nat_lock);
+DECLARE_RWLOCK_EXTERN(ip_conntrack_lock);
 
 /* Calculated at init based on memory size */
 static unsigned int ip_nat_htable_size;
@@ -628,6 +633,7 @@ ip_nat_setup_info(struct ip_conntrack *conntrack,
 	}
 
 	/* If there's a helper, assign it; based on new tuple. */
+	if (!conntrack->master)
 		info->helper = LIST_FIND(&helpers, helper_cmp, struct ip_nat_helper *,
 					 &reply);
 
@@ -724,6 +730,21 @@ manip_pkt(u_int16_t proto, struct iphdr *iph, size_t len,
 #endif
 }
 
+static inline int exp_for_packet(struct ip_conntrack_expect *exp,
+			         struct sk_buff **pskb)
+{
+	struct ip_conntrack_protocol *proto;
+	int ret = 1;
+
+	READ_LOCK(&ip_conntrack_lock);
+	proto = ip_ct_find_proto((*pskb)->nh.iph->protocol);
+	if (proto->exp_matches_pkt)
+		ret = proto->exp_matches_pkt(exp, pskb);
+	READ_UNLOCK(&ip_conntrack_lock);
+
+	return ret;
+}
+
 /* Do packet manipulations according to binding. */
 unsigned int
 do_bindings(struct ip_conntrack *ct,
@@ -735,6 +756,7 @@ do_bindings(struct ip_conntrack *ct,
 	unsigned int i;
 	struct ip_nat_helper *helper;
 	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+	int is_tcp = (*pskb)->nh.iph->protocol == IPPROTO_TCP;
 
 	/* Need nat lock to protect against modification, but neither
 	   conntrack (referenced) and helper (deleted with
@@ -773,11 +795,66 @@ do_bindings(struct ip_conntrack *ct,
 	READ_UNLOCK(&ip_nat_lock);
 
 	if (helper) {
+		struct ip_conntrack_expect *exp = NULL;
+		struct list_head *cur_item;
+		int ret = NF_ACCEPT;
+
+		DEBUGP("do_bindings: helper existing for (%p)\n", ct);
+
 		/* Always defragged for helpers */
 		IP_NF_ASSERT(!((*pskb)->nh.iph->frag_off
 			       & __constant_htons(IP_MF|IP_OFFSET)));
-		return helper->help(ct, info, ctinfo, hooknum, pskb);
-	} else return NF_ACCEPT;
+
+		/* Have to grab read lock before sibling_list traversal */
+		READ_LOCK(&ip_conntrack_lock);
+		list_for_each(cur_item, &ct->sibling_list) { 
+			exp = list_entry(cur_item, struct ip_conntrack_expect, 
+					 expected_list);
+					 
+			/* if this expectation is already established, skip */
+			if (exp->sibling)
+				continue;
+
+			if (exp_for_packet(exp, pskb)) {
+				/* FIXME: May be true multiple times in the case of UDP!! */
+				DEBUGP("calling nat helper (exp=%p) for packet\n",
+					exp);
+				ret = helper->help(ct, exp, info, ctinfo, 
+						   hooknum, pskb);
+				if (ret != NF_ACCEPT) {
+					READ_UNLOCK(&ip_conntrack_lock);
+					return ret;
+				}
+			}
+		}
+		/* Helper might want to manip the packet even when there is no expectation */
+		if (!exp && helper->flags & IP_NAT_HELPER_F_ALWAYS) {
+			DEBUGP("calling nat helper for packet without expectation\n");
+			ret = helper->help(ct, NULL, info, ctinfo, 
+					   hooknum, pskb);
+			if (ret != NF_ACCEPT) {
+				READ_UNLOCK(&ip_conntrack_lock);
+				return ret;
+			}
+		}
+		READ_UNLOCK(&ip_conntrack_lock);
+		
+		/* Adjust sequence number only once per packet 
+		 * (helper is called at all hooks) */
+		if (is_tcp && (hooknum == NF_IP_POST_ROUTING
+			       || hooknum == NF_IP_LOCAL_IN)) {
+			DEBUGP("ip_nat_core: adjusting sequence number\n");
+			/* future: put this in a l4-proto specific function,
+			 * and call this function here. */
+			ip_nat_seq_adjust(*pskb, ct, ctinfo);
+		}
+
+		return ret;
+
+	} else 
+		return NF_ACCEPT;
+
+	/* not reached */
 }
 
 unsigned int

net/ipv4/netfilter/ip_nat_ftp.c

@@ -28,38 +28,30 @@ DECLARE_LOCK_EXTERN(ip_ftp_lock);
 
 /* FIXME: Time out? --RR */
 
-static int
+static unsigned int
 ftp_nat_expected(struct sk_buff **pskb,
 		 unsigned int hooknum,
 		 struct ip_conntrack *ct,
-		 struct ip_nat_info *info,
-		 struct ip_conntrack *master,
-		 struct ip_nat_info *masterinfo,
-		 unsigned int *verdict)
+		 struct ip_nat_info *info)
 {
 	struct ip_nat_multi_range mr;
 	u_int32_t newdstip, newsrcip, newip;
-	struct ip_ct_ftp *ftpinfo;
+	struct ip_ct_ftp_expect *exp_ftp_info;
+
+	struct ip_conntrack *master = master_ct(ct);
 	
 	IP_NF_ASSERT(info);
 	IP_NF_ASSERT(master);
-	IP_NF_ASSERT(masterinfo);
 
 	IP_NF_ASSERT(!(info->initialized & (1<<HOOK2MANIP(hooknum))));
 
 	DEBUGP("nat_expected: We have a connection!\n");
-	/* Master must be an ftp connection */
-	ftpinfo = &master->help.ct_ftp_info;
+	exp_ftp_info = &ct->master->help.exp_ftp_info;
 
 	LOCK_BH(&ip_ftp_lock);
-	if (ftpinfo->is_ftp != 21) {
-		UNLOCK_BH(&ip_ftp_lock);
-		DEBUGP("nat_expected: master not ftp\n");
-		return 0;
-	}
 
-	if (ftpinfo->ftptype == IP_CT_FTP_PORT
-	    || ftpinfo->ftptype == IP_CT_FTP_EPRT) {
+	if (exp_ftp_info->ftptype == IP_CT_FTP_PORT
+	    || exp_ftp_info->ftptype == IP_CT_FTP_EPRT) {
 		/* PORT command: make connection go to the client. */
 		newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
 		newsrcip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
@@ -92,11 +84,9 @@ ftp_nat_expected(struct sk_buff **pskb,
 		mr.range[0].flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
 		mr.range[0].min = mr.range[0].max
 			= ((union ip_conntrack_manip_proto)
-				{ htons(ftpinfo->port) });
+				{ htons(exp_ftp_info->port) });
 	}
-	*verdict = ip_nat_setup_info(ct, &mr, hooknum);
-
-	return 1;
+	return ip_nat_setup_info(ct, &mr, hooknum);
 }
 
 static int
@@ -176,27 +166,22 @@ static int (*mangle[])(struct sk_buff **, u_int32_t, u_int16_t,
     [IP_CT_FTP_EPSV] mangle_epsv_packet
 };
 
-static int ftp_data_fixup(const struct ip_ct_ftp *ct_ftp_info,
+static int ftp_data_fixup(const struct ip_ct_ftp_expect *ct_ftp_info,
 			  struct ip_conntrack *ct,
-			  unsigned int datalen,
 			  struct sk_buff **pskb,
-			  enum ip_conntrack_info ctinfo)
+			  enum ip_conntrack_info ctinfo,
+			  struct ip_conntrack_expect *expect)
 {
 	u_int32_t newip;
 	struct iphdr *iph = (*pskb)->nh.iph;
 	struct tcphdr *tcph = (void *)iph + iph->ihl*4;
 	u_int16_t port;
-	struct ip_conntrack_tuple tuple;
-	/* Don't care about source port */
-	const struct ip_conntrack_tuple mask
-		= { { 0xFFFFFFFF, { 0 } },
-		    { 0xFFFFFFFF, { 0xFFFF }, 0xFFFF } };
+	struct ip_conntrack_tuple newtuple;
 
-	memset(&tuple, 0, sizeof(tuple));
 	MUST_BE_LOCKED(&ip_ftp_lock);
-	DEBUGP("FTP_NAT: seq %u + %u in %u + %u\n",
-	       ct_ftp_info->seq, ct_ftp_info->len,
-	       ntohl(tcph->seq), datalen);
+	DEBUGP("FTP_NAT: seq %u + %u in %u\n",
+	       expect->seq, ct_ftp_info->len,
+	       ntohl(tcph->seq));
 
 	/* Change address inside packet to match way we're mapping
 	   this connection. */
@@ -206,29 +191,34 @@ static int ftp_data_fixup(const struct ip_ct_ftp *ct_ftp_info,
 		   is */
 		newip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
 		/* Expect something from client->server */
-		tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
-		tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
+		newtuple.src.ip = 
+			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
+		newtuple.dst.ip = 
+			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
 	} else {
 		/* PORT command: must be where server thinks client is */
 		newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
 		/* Expect something from server->client */
-		tuple.src.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip;
-		tuple.dst.ip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
+		newtuple.src.ip = 
+			ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip;
+		newtuple.dst.ip = 
+			ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
 	}
-	tuple.dst.protonum = IPPROTO_TCP;
+	newtuple.dst.protonum = IPPROTO_TCP;
+	newtuple.src.u.tcp.port = expect->tuple.src.u.tcp.port;
 
 	/* Try to get same port: if not, try to change it. */
 	for (port = ct_ftp_info->port; port != 0; port++) {
-		tuple.dst.u.tcp.port = htons(port);
+		newtuple.dst.u.tcp.port = htons(port);
 
-		if (ip_conntrack_expect_related(ct, &tuple, &mask, NULL) == 0)
+		if (ip_conntrack_change_expect(expect, &newtuple) == 0)
 			break;
 	}
 	if (port == 0)
 		return 0;
 
 	if (!mangle[ct_ftp_info->ftptype](pskb, newip, port,
-					  ct_ftp_info->seq - ntohl(tcph->seq),
+					  expect->seq - ntohl(tcph->seq),
 					  ct_ftp_info->len, ct, ctinfo))
 		return 0;
 
@@ -236,6 +226,7 @@ static int ftp_data_fixup(const struct ip_ct_ftp *ct_ftp_info,
 }
 
 static unsigned int help(struct ip_conntrack *ct,
+			 struct ip_conntrack_expect *exp,
 			 struct ip_nat_info *info,
 			 enum ip_conntrack_info ctinfo,
 			 unsigned int hooknum,
@@ -245,13 +236,12 @@ static unsigned int help(struct ip_conntrack *ct,
 	struct tcphdr *tcph = (void *)iph + iph->ihl*4;
 	unsigned int datalen;
 	int dir;
-	int score;
-	struct ip_ct_ftp *ct_ftp_info
-		= &ct->help.ct_ftp_info;
+	struct ip_ct_ftp_expect *ct_ftp_info;
+
+	if (!exp)
+		DEBUGP("ip_nat_ftp: no exp!!");
 
-	/* Delete SACK_OK on initial TCP SYNs. */
-	if (tcph->syn && !tcph->ack)
-		ip_nat_delete_sack(*pskb, tcph);
+	ct_ftp_info = &exp->help.exp_ftp_info;
 
 	/* Only mangle things once: original direction in POST_ROUTING
 	   and reply direction on PRE_ROUTING. */
@@ -267,50 +257,34 @@ static unsigned int help(struct ip_conntrack *ct,
 	}
 
 	datalen = (*pskb)->len - iph->ihl * 4 - tcph->doff * 4;
-	score = 0;
 	LOCK_BH(&ip_ftp_lock);
-	if (ct_ftp_info->len) {
 	/* If it's in the right range... */
-		score += between(ct_ftp_info->seq, ntohl(tcph->seq),
-				 ntohl(tcph->seq) + datalen);
-		score += between(ct_ftp_info->seq + ct_ftp_info->len,
+	if (between(exp->seq + ct_ftp_info->len,
 		    ntohl(tcph->seq),
-				 ntohl(tcph->seq) + datalen);
-		if (score == 1) {
+		    ntohl(tcph->seq) + datalen)) {
+		if (!ftp_data_fixup(ct_ftp_info, ct, pskb, ctinfo, exp)) {
+			UNLOCK_BH(&ip_ftp_lock);
+			return NF_DROP;
+		}
+	} else {
 		/* Half a match?  This means a partial retransmisison.
 		   It's a cracker being funky. */
 		if (net_ratelimit()) {
 			printk("FTP_NAT: partial packet %u/%u in %u/%u\n",
-				       ct_ftp_info->seq, ct_ftp_info->len,
+			       exp->seq, ct_ftp_info->len,
 			       ntohl(tcph->seq),
 			       ntohl(tcph->seq) + datalen);
 		}
 		UNLOCK_BH(&ip_ftp_lock);
 		return NF_DROP;
-		} else if (score == 2) {
-			if (!ftp_data_fixup(ct_ftp_info, ct, datalen,
-					    pskb, ctinfo)) {
-				UNLOCK_BH(&ip_ftp_lock);
-				return NF_DROP;
-			}
-			/* skb may have been reallocated */
-			iph = (*pskb)->nh.iph;
-			tcph = (void *)iph + iph->ihl*4;
-		}
 	}
-
 	UNLOCK_BH(&ip_ftp_lock);
 
-	ip_nat_seq_adjust(*pskb, ct, ctinfo);
-
 	return NF_ACCEPT;
 }
 
 static struct ip_nat_helper ftp[MAX_PORTS];
-static char ftp_names[MAX_PORTS][6];
-
-static struct ip_nat_expect ftp_expect
-= { { NULL, NULL }, ftp_nat_expected };
+static char ftp_names[MAX_PORTS][10];
 
 /* Not __exit: called from init() */
 static void fini(void)
@@ -321,19 +295,15 @@ static void fini(void)
 		DEBUGP("ip_nat_ftp: unregistering port %d\n", ports[i]);
 		ip_nat_helper_unregister(&ftp[i]);
 	}
-
-	ip_nat_expect_unregister(&ftp_expect);
 }
 
 static int __init init(void)
 {
-	int i, ret;
+	int i, ret = 0;
 	char *tmpname;
 
-	ret = ip_nat_expect_register(&ftp_expect);
-	if (ret == 0) {
 	if (ports[0] == 0)
-			ports[0] = 21;
+		ports[0] = FTP_PORT;
 
 	for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
 
@@ -344,9 +314,15 @@ static int __init init(void)
 		ftp[i].mask.dst.protonum = 0xFFFF;
 		ftp[i].mask.src.u.tcp.port = 0xFFFF;
 		ftp[i].help = help;
+		ftp[i].me = THIS_MODULE;
+		ftp[i].flags = 0;
+		ftp[i].expect = ftp_nat_expected;
 
 		tmpname = &ftp_names[i][0];
-			sprintf(tmpname, "ftp%2.2d", i);
+		if (ports[i] == FTP_PORT)
+			sprintf(tmpname, "ftp");
+		else
+			sprintf(tmpname, "ftp-%d", i);
 		ftp[i].name = tmpname;
 
 		DEBUGP("ip_nat_ftp: Trying to register for port %d\n",
@@ -354,16 +330,14 @@ static int __init init(void)
 		ret = ip_nat_helper_register(&ftp[i]);
 
 		if (ret) {
-				printk("ip_nat_ftp: error registering helper for port %d\n", ports[i]);
+			printk("ip_nat_ftp: error registering "
+			       "helper for port %d\n", ports[i]);
 			fini();
 			return ret;
 		}
 		ports_c++;
 	}
 
-	} else {
-		ip_nat_expect_unregister(&ftp_expect);
-	}
 	return ret;
 }
 

net/ipv4/netfilter/ip_nat_helper.c

 /* ip_nat_mangle.c - generic support functions for NAT helpers 
  *
- * (C) 2000 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2000-2002 by Harald Welte <laforge@gnumonks.org>
  *
  * distributed under the terms of GNU GPL
+ *
+ * 	14 Jan 2002 Harald Welte <laforge@gnumonks.org>:
+ *		- add support for SACK adjustment 
+ *	14 Mar 2002 Harald Welte <laforge@gnumonks.org>:
+ *		- merge SACK support into newnat API
  */
 #include <linux/version.h>
+#include <linux/config.h>
 #include <linux/module.h>
+#include <linux/kmod.h>
 #include <linux/types.h>
 #include <linux/timer.h>
 #include <linux/skbuff.h>
@@ -19,6 +26,8 @@
 #define ASSERT_READ_LOCK(x) MUST_BE_READ_LOCKED(&ip_nat_lock)
 #define ASSERT_WRITE_LOCK(x) MUST_BE_WRITE_LOCKED(&ip_nat_lock)
 
+#include <linux/netfilter_ipv4/ip_conntrack.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
 #include <linux/netfilter_ipv4/ip_nat.h>
 #include <linux/netfilter_ipv4/ip_nat_protocol.h>
 #include <linux/netfilter_ipv4/ip_nat_core.h>
@@ -199,6 +208,103 @@ ip_nat_mangle_tcp_packet(struct sk_buff **skb,
 	return 1;
 }
 
+/* Adjust one found SACK option including checksum correction */
+static void
+sack_adjust(struct tcphdr *tcph, 
+	    unsigned char *ptr, 
+	    struct ip_nat_seq *natseq)
+{
+	struct tcp_sack_block *sp = (struct tcp_sack_block *)(ptr+2);
+	int num_sacks = (ptr[1] - TCPOLEN_SACK_BASE)>>3;
+	int i;
+
+	for (i = 0; i < num_sacks; i++, sp++) {
+		u_int32_t new_start_seq, new_end_seq;
+
+		if (after(ntohl(sp->start_seq) - natseq->offset_before,
+			  natseq->correction_pos))
+			new_start_seq = ntohl(sp->start_seq) 
+					- natseq->offset_after;
+		else
+			new_start_seq = ntohl(sp->start_seq) 
+					- natseq->offset_before;
+		new_start_seq = htonl(new_start_seq);
+
+		if (after(ntohl(sp->end_seq) - natseq->offset_before,
+			  natseq->correction_pos))
+			new_end_seq = ntohl(sp->end_seq)
+				      - natseq->offset_after;
+		else
+			new_end_seq = ntohl(sp->end_seq)
+				      - natseq->offset_before;
+		new_end_seq = htonl(new_end_seq);
+
+		DEBUGP("sack_adjust: start_seq: %d->%d, end_seq: %d->%d\n",
+			ntohl(sp->start_seq), new_start_seq,
+			ntohl(sp->end_seq), new_end_seq);
+
+		tcph->check = 
+			ip_nat_cheat_check(~sp->start_seq, new_start_seq,
+					   ip_nat_cheat_check(~sp->end_seq, 
+						   	      new_end_seq,
+							      tcph->check));
+
+		sp->start_seq = new_start_seq;
+		sp->end_seq = new_end_seq;
+	}
+}
+			
+
+/* TCP SACK sequence number adjustment, return 0 if sack found and adjusted */
+static inline int
+ip_nat_sack_adjust(struct sk_buff *skb,
+			struct ip_conntrack *ct,
+			enum ip_conntrack_info ctinfo)
+{
+	struct iphdr *iph;
+	struct tcphdr *tcph;
+	unsigned char *ptr;
+	int length, dir, sack_adjusted = 0;
+
+	iph = skb->nh.iph;
+	tcph = (void *)iph + iph->ihl*4;
+	length = (tcph->doff*4)-sizeof(struct tcphdr);
+	ptr = (unsigned char *)(tcph+1);
+
+	dir = CTINFO2DIR(ctinfo);
+
+	while (length > 0) {
+		int opcode = *ptr++;
+		int opsize;
+
+		switch (opcode) {
+		case TCPOPT_EOL:
+			return !sack_adjusted;
+		case TCPOPT_NOP:
+			length--;
+			continue;
+		default:
+			opsize = *ptr++;
+			if (opsize > length) /* no partial opts */
+				return !sack_adjusted;
+			if (opcode == TCPOPT_SACK) {
+				/* found SACK */
+				if((opsize >= (TCPOLEN_SACK_BASE
+					       +TCPOLEN_SACK_PERBLOCK)) &&
+				   !((opsize - TCPOLEN_SACK_BASE)
+				     % TCPOLEN_SACK_PERBLOCK))
+					sack_adjust(tcph, ptr-2,
+						    &ct->nat.info.seq[!dir]);
+				
+				sack_adjusted = 1;
+			}
+			ptr += opsize-2;
+			length -= opsize;
+		}
+	}
+	return !sack_adjusted;
+}
+
 /* TCP sequence number adjustment */
 int 
 ip_nat_seq_adjust(struct sk_buff *skb, 
@@ -243,51 +349,9 @@ ip_nat_seq_adjust(struct sk_buff *skb,
 	tcph->seq = newseq;
 	tcph->ack_seq = newack;
 
-	return 0;
-}
+	ip_nat_sack_adjust(skb, ct, ctinfo);
 
-/* Grrr... SACK.  Fuck me even harder.  Don't want to fix it on the
-   fly, so blow it away. */
-void
-ip_nat_delete_sack(struct sk_buff *skb, struct tcphdr *tcph)
-{
-	unsigned int i;
-	u_int8_t *opt = (u_int8_t *)tcph;
-
-	DEBUGP("Seeking SACKPERM in SYN packet (doff = %u).\n",
-	       tcph->doff * 4);
-	for (i = sizeof(struct tcphdr); i < tcph->doff * 4;) {
-		DEBUGP("%u ", opt[i]);
-		switch (opt[i]) {
-		case TCPOPT_NOP:
-		case TCPOPT_EOL:
-			i++;
-			break;
-
-		case TCPOPT_SACK_PERM:
-			goto found_opt;
-
-		default:
-			/* Worst that can happen: it will take us over. */
-			i += opt[i+1] ?: 1;
-		}
-	}
-	DEBUGP("\n");
-	return;
-
- found_opt:
-	DEBUGP("\n");
-	DEBUGP("Found SACKPERM at offset %u.\n", i);
-
-	/* Must be within TCP header, and valid SACK perm. */
-	if (i + opt[i+1] <= tcph->doff*4 && opt[i+1] == 2) {
-		/* Replace with NOPs. */
-		tcph->check
-			= ip_nat_cheat_check(*((u_int16_t *)(opt + i))^0xFFFF,
-					     (TCPOPT_NOP<<8)|TCPOPT_NOP, tcph->check);
-		opt[i] = opt[i+1] = TCPOPT_NOP;
-	}
-	else DEBUGP("Something wrong with SACK_PERM.\n");
+	return 0;
 }
 
 static inline int
@@ -297,10 +361,51 @@ helper_cmp(const struct ip_nat_helper *helper,
 	return ip_ct_tuple_mask_cmp(tuple, &helper->tuple, &helper->mask);
 }
 
+#define MODULE_MAX_NAMELEN		32
+
 int ip_nat_helper_register(struct ip_nat_helper *me)
 {
 	int ret = 0;
 
+	if (me->me && !(me->flags & IP_NAT_HELPER_F_STANDALONE)) {
+		struct ip_conntrack_helper *ct_helper;
+		
+		if ((ct_helper = ip_ct_find_helper(&me->tuple))
+		    && ct_helper->me) {
+			__MOD_INC_USE_COUNT(ct_helper->me);
+		} else {
+
+			/* We are a NAT helper for protocol X.  If we need
+			 * respective conntrack helper for protoccol X, compute
+			 * conntrack helper name and try to load module */
+			char name[MODULE_MAX_NAMELEN];
+			const char *tmp = me->me->name;
+			
+			if (strlen(tmp) + 6 > MODULE_MAX_NAMELEN) {
+				printk(__FUNCTION__ ": unable to "
+				       "compute conntrack helper name "
+				       "from %s\n", tmp);
+				return -EBUSY;
+			}
+			tmp += 6;
+			sprintf(name, "ip_conntrack%s", tmp);
+#ifdef CONFIG_KMOD
+			if (!request_module(name)
+			    && (ct_helper = ip_ct_find_helper(&me->tuple))
+			    && ct_helper->me) {
+				__MOD_INC_USE_COUNT(ct_helper->me);
+			} else {
+				printk("unable to load module %s\n", name);
+				return -EBUSY;
+			}
+#else
+			printk("unable to load module %s automatically "
+			       "because kernel was compiled without kernel "
+			       "module loader support\n", name);
+			return -EBUSY;
+#endif
+		}
+	}
 	WRITE_LOCK(&ip_nat_lock);
 	if (LIST_FIND(&helpers, helper_cmp, struct ip_nat_helper *,&me->tuple))
 		ret = -EBUSY;
@@ -327,8 +432,14 @@ kill_helper(const struct ip_conntrack *i, void *helper)
 
 void ip_nat_helper_unregister(struct ip_nat_helper *me)
 {
+	int found = 0;
+	
 	WRITE_LOCK(&ip_nat_lock);
+	/* Autoloading conntrack helper might have failed */
+	if (LIST_FIND(&helpers, helper_cmp, struct ip_nat_helper *,&me->tuple)) {
 		LIST_DELETE(&helpers, me);
+		found = 1;
+	}
 	WRITE_UNLOCK(&ip_nat_lock);
 
 	/* Someone could be still looking at the helper in a bh. */
@@ -344,5 +455,19 @@ void ip_nat_helper_unregister(struct ip_nat_helper *me)
 	   worse. --RR */
 	ip_ct_selective_cleanup(kill_helper, me);
 
+	if (found)
 		MOD_DEC_USE_COUNT;
+
+	/* If we are no standalone NAT helper, we need to decrement usage count
+	 * on our conntrack helper */
+	if (me->me && !(me->flags & IP_NAT_HELPER_F_STANDALONE)) {
+		struct ip_conntrack_helper *ct_helper;
+		
+		if ((ct_helper = ip_ct_find_helper(&me->tuple))
+		    && ct_helper->me) {
+			__MOD_DEC_USE_COUNT(ct_helper->me);
+		} else 
+			printk(__FUNCTION__ ": unable to decrement usage count"
+			       " of conntrack helper %s\n", me->me->name);
+	}
 }

net/ipv4/netfilter/ip_nat_irc.c

@@ -51,42 +51,29 @@ DECLARE_LOCK_EXTERN(ip_irc_lock);
 
 /* FIXME: Time out? --RR */
 
-static int
+static unsigned int
 irc_nat_expected(struct sk_buff **pskb,
 		 unsigned int hooknum,
 		 struct ip_conntrack *ct,
-		 struct ip_nat_info *info,
-		 struct ip_conntrack *master,
-		 struct ip_nat_info *masterinfo, unsigned int *verdict)
+		 struct ip_nat_info *info)
 {
 	struct ip_nat_multi_range mr;
 	u_int32_t newdstip, newsrcip, newip;
-	struct ip_ct_irc *ircinfo;
+
+	struct ip_conntrack *master = master_ct(ct);
 
 	IP_NF_ASSERT(info);
 	IP_NF_ASSERT(master);
-	IP_NF_ASSERT(masterinfo);
 
 	IP_NF_ASSERT(!(info->initialized & (1 << HOOK2MANIP(hooknum))));
 
 	DEBUGP("nat_expected: We have a connection!\n");
 
-	/* Master must be an irc connection */
-	ircinfo = &master->help.ct_irc_info;
-	LOCK_BH(&ip_irc_lock);
-	if (ircinfo->is_irc != IP_CONNTR_IRC) {
-		UNLOCK_BH(&ip_irc_lock);
-		DEBUGP("nat_expected: master not irc\n");
-		return 0;
-	}
-
 	newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
 	newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
 	DEBUGP("nat_expected: DCC cmd. %u.%u.%u.%u->%u.%u.%u.%u\n",
 	       NIPQUAD(newsrcip), NIPQUAD(newdstip));
 
-	UNLOCK_BH(&ip_irc_lock);
-
 	if (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC)
 		newip = newsrcip;
 	else
@@ -99,16 +86,14 @@ irc_nat_expected(struct sk_buff **pskb,
 	mr.range[0].flags = IP_NAT_RANGE_MAP_IPS;
 	mr.range[0].min_ip = mr.range[0].max_ip = newip;
 
-	*verdict = ip_nat_setup_info(ct, &mr, hooknum);
-
-	return 1;
+	return ip_nat_setup_info(ct, &mr, hooknum);
 }
 
-static int irc_data_fixup(const struct ip_ct_irc *ct_irc_info,
+static int irc_data_fixup(const struct ip_ct_irc_expect *ct_irc_info,
 			  struct ip_conntrack *ct,
-			  unsigned int datalen,
 			  struct sk_buff **pskb,
-			  enum ip_conntrack_info ctinfo)
+			  enum ip_conntrack_info ctinfo,
+			  struct ip_conntrack_expect *expect)
 {
 	u_int32_t newip;
 	struct ip_conntrack_tuple t;
@@ -121,9 +106,9 @@ static int irc_data_fixup(const struct ip_ct_irc *ct_irc_info,
 
 	MUST_BE_LOCKED(&ip_irc_lock);
 
-	DEBUGP("IRC_NAT: info (seq %u + %u) packet(seq %u + %u)\n",
-	       ct_irc_info->seq, ct_irc_info->len,
-	       ntohl(tcph->seq), datalen);
+	DEBUGP("IRC_NAT: info (seq %u + %u) in %u\n",
+	       expect->seq, ct_irc_info->len,
+	       ntohl(tcph->seq));
 
 	newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
 
@@ -133,13 +118,11 @@ static int irc_data_fixup(const struct ip_ct_irc *ct_irc_info,
 	   only set in ip_conntrack_irc, with ip_irc_lock held
 	   writable */
 
-	t = ct->expected.tuple;
+	t = expect->tuple;
 	t.dst.ip = newip;
 	for (port = ct_irc_info->port; port != 0; port++) {
 		t.dst.u.tcp.port = htons(port);
-		if (ip_conntrack_expect_related(ct, &t,
-						&ct->expected.mask,
-						NULL) == 0) {
+		if (ip_conntrack_change_expect(expect, &t) == 0) {
 			DEBUGP("using port %d", port);
 			break;
 		}
@@ -166,26 +149,28 @@ static int irc_data_fixup(const struct ip_ct_irc *ct_irc_info,
 	       buffer, NIPQUAD(newip), port);
 
 	return ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, 
-					ct_irc_info->seq - ntohl(tcph->seq),
+					expect->seq - ntohl(tcph->seq),
 					ct_irc_info->len, buffer, 
 					strlen(buffer));
 }
 
 static unsigned int help(struct ip_conntrack *ct,
+			 struct ip_conntrack_expect *exp,
 			 struct ip_nat_info *info,
 			 enum ip_conntrack_info ctinfo,
-			 unsigned int hooknum, struct sk_buff **pskb)
+			 unsigned int hooknum, 
+			 struct sk_buff **pskb)
 {
 	struct iphdr *iph = (*pskb)->nh.iph;
 	struct tcphdr *tcph = (void *) iph + iph->ihl * 4;
 	unsigned int datalen;
 	int dir;
-	int score;
-	struct ip_ct_irc *ct_irc_info = &ct->help.ct_irc_info;
+	struct ip_ct_irc_expect *ct_irc_info;
 
-	/* Delete SACK_OK on initial TCP SYNs. */
-	if (tcph->syn && !tcph->ack)
-		ip_nat_delete_sack(*pskb, tcph);
+	if (!exp)
+		DEBUGP("ip_nat_irc: no exp!!");
+		
+	ct_irc_info = &exp->help.exp_irc_info;
 
 	/* Only mangle things once: original direction in POST_ROUTING
 	   and reply direction on PRE_ROUTING. */
@@ -202,55 +187,35 @@ static unsigned int help(struct ip_conntrack *ct,
 	DEBUGP("got beyond not touching\n");
 
 	datalen = (*pskb)->len - iph->ihl * 4 - tcph->doff * 4;
-	score = 0;
 	LOCK_BH(&ip_irc_lock);
-	if (ct_irc_info->len) {
-		DEBUGP("got beyond ct_irc_info->len\n");
-
-		/* If it's in the right range... */
-		score += between(ct_irc_info->seq, ntohl(tcph->seq),
-				 ntohl(tcph->seq) + datalen);
-		score += between(ct_irc_info->seq + ct_irc_info->len,
+	/* Check wether the whole IP/address pattern is carried in the payload */
+	if (between(exp->seq + ct_irc_info->len,
 		    ntohl(tcph->seq),
-				 ntohl(tcph->seq) + datalen);
-		if (score == 1) {
+		    ntohl(tcph->seq) + datalen)) {
+		if (!irc_data_fixup(ct_irc_info, ct, pskb, ctinfo, exp)) {
+			UNLOCK_BH(&ip_irc_lock);
+			return NF_DROP;
+		}
+	} else { 
 		/* Half a match?  This means a partial retransmisison.
 		   It's a cracker being funky. */
 		if (net_ratelimit()) {
 			printk
 			    ("IRC_NAT: partial packet %u/%u in %u/%u\n",
-				     ct_irc_info->seq, ct_irc_info->len,
+			     exp->seq, ct_irc_info->len,
 			     ntohl(tcph->seq),
 			     ntohl(tcph->seq) + datalen);
 		}
 		UNLOCK_BH(&ip_irc_lock);
 		return NF_DROP;
-		} else if (score == 2) {
-			DEBUGP("IRC_NAT: score=2, calling fixup\n");
-			if (!irc_data_fixup(ct_irc_info, ct, datalen,
-					    pskb, ctinfo)) {
-				UNLOCK_BH(&ip_irc_lock);
-				return NF_DROP;
 	}
-			/* skb may have been reallocated */
-			iph = (*pskb)->nh.iph;
-			tcph = (void *) iph + iph->ihl * 4;
-		}
-	}
-
 	UNLOCK_BH(&ip_irc_lock);
 
-	ip_nat_seq_adjust(*pskb, ct, ctinfo);
-
 	return NF_ACCEPT;
 }
 
 static struct ip_nat_helper ip_nat_irc_helpers[MAX_PORTS];
-static char ip_nih_names[MAX_PORTS][6];
-
-static struct ip_nat_expect irc_expect
-    = { {NULL, NULL}, irc_nat_expected };
-
+static char irc_names[MAX_PORTS][10];
 
 /* This function is intentionally _NOT_ defined as  __exit, because
  * it is needed by init() */
@@ -263,20 +228,17 @@ static void fini(void)
 		       ports[i]);
 		ip_nat_helper_unregister(&ip_nat_irc_helpers[i]);
 	} 
-	ip_nat_expect_unregister(&irc_expect);
 }
+
 static int __init init(void)
 {
-	int ret;
+	int ret = 0;
 	int i;
 	struct ip_nat_helper *hlpr;
 	char *tmpname;
 
-	ret = ip_nat_expect_register(&irc_expect);
-	if (ret == 0) {
-
 	if (ports[0] == 0) {
-			ports[0] = 6667;
+		ports[0] = IRC_PORT;
 	}
 
 	for (i = 0; (i < MAX_PORTS) && ports[i] != 0; i++) {
@@ -289,11 +251,17 @@ static int __init init(void)
 		hlpr->mask.src.u.tcp.port = 0xFFFF;
 		hlpr->mask.dst.protonum = 0xFFFF;
 		hlpr->help = help;
+		hlpr->flags = 0;
+		hlpr->me = THIS_MODULE;
+		hlpr->expect = irc_nat_expected;
 
-			tmpname = &ip_nih_names[i][0];
-			sprintf(tmpname, "irc%2.2d", i);
-
+		tmpname = &irc_names[i][0];
+		if (ports[i] == IRC_PORT)
+			sprintf(tmpname, "irc");
+		else
+			sprintf(tmpname, "irc-%d", i);
 		hlpr->name = tmpname;
+
 		DEBUGP
 		    ("ip_nat_irc: Trying to register helper for port %d: name %s\n",
 		     ports[i], hlpr->name);
@@ -308,7 +276,6 @@ static int __init init(void)
 		}
 		ports_c++;
 	}
-	}
 	return ret;
 }
 

net/ipv4/netfilter/ip_nat_proto_tcp.c

@@ -4,7 +4,6 @@
 #include <linux/ip.h>
 #include <linux/tcp.h>
 #include <linux/if.h>
-
 #include <linux/netfilter_ipv4/ip_nat.h>
 #include <linux/netfilter_ipv4/ip_nat_rule.h>
 #include <linux/netfilter_ipv4/ip_nat_protocol.h>

net/ipv4/netfilter/ip_nat_proto_unknown.c

 /* The "unknown" protocol.  This is what is used for protocols we
- * don't understand.  It's returned by find_proto().
+ * don't understand.  It's returned by ip_ct_find_proto().
  */
 
 #include <linux/types.h>

net/ipv4/netfilter/ip_nat_rule.c

@@ -106,8 +106,6 @@ static struct ipt_table nat_table
 = { { NULL, NULL }, "nat", &nat_initial_table.repl,
     NAT_VALID_HOOKS, RW_LOCK_UNLOCKED, NULL, THIS_MODULE };
 
-LIST_HEAD(nat_expect_list);
-
 /* Source NAT */
 static unsigned int ipt_snat_target(struct sk_buff **pskb,
 				    unsigned int hooknum,
@@ -254,19 +252,6 @@ alloc_null_binding(struct ip_conntrack *conntrack,
 	return ip_nat_setup_info(conntrack, &mr, hooknum);
 }
 
-static inline int call_expect(const struct ip_nat_expect *i,
-			      struct sk_buff **pskb,
-			      unsigned int hooknum,
-			      struct ip_conntrack *ct,
-			      struct ip_nat_info *info,
-			      struct ip_conntrack *master,
-			      struct ip_nat_info *masterinfo,
-			      unsigned int *verdict)
-{
-	return i->expect(pskb, hooknum, ct, info, master, masterinfo,
-			 verdict);
-}
-
 int ip_nat_rule_find(struct sk_buff **pskb,
 		     unsigned int hooknum,
 		     const struct net_device *in,
@@ -276,19 +261,8 @@ int ip_nat_rule_find(struct sk_buff **pskb,
 {
 	int ret;
 
-	/* Master won't vanish while this ctrack still alive */
-	if (ct->master.master) {
-		struct ip_conntrack *master;
-
-		master = (struct ip_conntrack *)ct->master.master;
-		if (LIST_FIND(&nat_expect_list,
-			      call_expect,
-			      struct ip_nat_expect *,
-			      pskb, hooknum, ct, info,
-			      master, &master->nat.info, &ret))
-			return ret;
-	}
 	ret = ipt_do_table(pskb, hooknum, in, out, &nat_table, NULL);
+
 	if (ret == NF_ACCEPT) {
 		if (!(info->initialized & (1 << HOOK2MANIP(hooknum))))
 			/* NUL mapping */
@@ -297,22 +271,6 @@ int ip_nat_rule_find(struct sk_buff **pskb,
 	return ret;
 }
 
-int ip_nat_expect_register(struct ip_nat_expect *expect)
-{
-	WRITE_LOCK(&ip_nat_lock);
-	list_prepend(&nat_expect_list, expect);
-	WRITE_UNLOCK(&ip_nat_lock);
-
-	return 0;
-}
-
-void ip_nat_expect_unregister(struct ip_nat_expect *expect)
-{
-	WRITE_LOCK(&ip_nat_lock);
-	LIST_DELETE(&nat_expect_list, expect);
-	WRITE_UNLOCK(&ip_nat_lock);
-}
-
 static struct ipt_target ipt_snat_reg
 = { { NULL, NULL }, "SNAT", ipt_snat_target, ipt_snat_checkentry, NULL };
 static struct ipt_target ipt_dnat_reg

net/ipv4/netfilter/ip_nat_snmp_basic.c

@@ -1244,6 +1244,7 @@ static int snmp_translate(struct ip_conntrack *ct,
  * NAT helper function, packets arrive here from NAT code.
  */
 static unsigned int nat_help(struct ip_conntrack *ct,
+			     struct ip_conntrack_expect *exp,
                              struct ip_nat_info *info,
                              enum ip_conntrack_info ctinfo,
                              unsigned int hooknum,
@@ -1304,19 +1305,27 @@ static unsigned int nat_help(struct ip_conntrack *ct,
 	return NF_DROP;
 }
 
-static struct ip_nat_helper snmp = { { NULL, NULL },
+static struct ip_nat_helper snmp = { 
+	{ NULL, NULL },
+	"snmp",
+	IP_NAT_HELPER_F_STANDALONE,
+	THIS_MODULE,
 	{ { 0, { __constant_htons(SNMP_PORT) } },
 	  { 0, { 0 }, IPPROTO_UDP } },
 	{ { 0, { 0xFFFF } },
 	  { 0, { 0 }, 0xFFFF } },
-	  nat_help, "snmp" };
+	nat_help, NULL };
  
-static struct ip_nat_helper snmp_trap = { { NULL, NULL },
+static struct ip_nat_helper snmp_trap = { 
+	{ NULL, NULL },
+	"snmp_trap",
+	IP_NAT_HELPER_F_STANDALONE,
+	THIS_MODULE,
 	{ { 0, { __constant_htons(SNMP_TRAP_PORT) } },
 	  { 0, { 0 }, IPPROTO_UDP } },
 	{ { 0, { 0xFFFF } },
 	  { 0, { 0 }, 0xFFFF } },
-	nat_help, "snmp_trap" };
+	nat_help, NULL };
 
 /*****************************************************************************
  *

net/ipv4/netfilter/ip_nat_standalone.c

@@ -5,7 +5,12 @@
 */
 
 /* (c) 1999 Paul `Rusty' Russell.  Licenced under the GNU General
-   Public Licence. */
+ * Public Licence.
+ *
+ * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
+ * 	- new API and handling of conntrack/nat helpers
+ * 	- now capable of multiple expectations for one master
+ * */
 
 #include <linux/config.h>
 #include <linux/types.h>
@@ -45,6 +50,15 @@
 			         : ((hooknum) == NF_IP_LOCAL_IN ? "LOCAL_IN"  \
 				    : "*ERROR*")))
 
+static inline int call_expect(struct ip_conntrack *master,
+			      struct sk_buff **pskb,
+			      unsigned int hooknum,
+			      struct ip_conntrack *ct,
+			      struct ip_nat_info *info)
+{
+	return master->nat.info.helper->expect(pskb, hooknum, ct, info);
+}
+
 static unsigned int
 ip_nat_fn(unsigned int hooknum,
 	  struct sk_buff **pskb,
@@ -111,8 +125,16 @@ ip_nat_fn(unsigned int hooknum,
 			int in_hashes = info->initialized;
 			unsigned int ret;
 
+			if (ct->master
+			    && master_ct(ct)->nat.info.helper
+			    && master_ct(ct)->nat.info.helper->expect) {
+				ret = call_expect(master_ct(ct), pskb, 
+						  hooknum, ct, info);
+			} else {
 				ret = ip_nat_rule_find(pskb, hooknum, in, out,
 						       ct, info);
+			}
+
 			if (ret != NF_ACCEPT) {
 				WRITE_UNLOCK(&ip_nat_lock);
 				return ret;
@@ -335,11 +357,7 @@ EXPORT_SYMBOL(ip_nat_protocol_register);
 EXPORT_SYMBOL(ip_nat_protocol_unregister);
 EXPORT_SYMBOL(ip_nat_helper_register);
 EXPORT_SYMBOL(ip_nat_helper_unregister);
-EXPORT_SYMBOL(ip_nat_expect_register);
-EXPORT_SYMBOL(ip_nat_expect_unregister);
 EXPORT_SYMBOL(ip_nat_cheat_check);
 EXPORT_SYMBOL(ip_nat_mangle_tcp_packet);
-EXPORT_SYMBOL(ip_nat_seq_adjust);
-EXPORT_SYMBOL(ip_nat_delete_sack);
 EXPORT_SYMBOL(ip_nat_used_tuple);
 MODULE_LICENSE("GPL");