[NETFILTER]: nf_nat: kill helper and seq_adjust hooks

Connection tracking helpers (specifically FTP) need to be called
before NAT sequence numbers adjustments are performed to be able
to compare them against previously seen ones. We've introduced
two new hooks around 2.6.11 to maintain this ordering when NAT
modules were changed to get called from conntrack helpers directly.

The cost of netfilter hooks is quite high and sequence number
adjustments are only rarely needed however. Add a RCU-protected
sequence number adjustment function pointer and call it from
IPv4 conntrack after calling the helper.

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 0 insertions, 35 deletions

diff --git a/net/ipv4/netfilter/nf_nat_standalone.c b/net/ipv4/netfilter/nf_nat_standalone.c
index a366b5865b9..b7dd695691a 100644
--- a/net/ipv4/netfilter/nf_nat_standalone.c
+++ b/net/ipv4/netfilter/nf_nat_standalone.c
@@ -245,25 +245,6 @@ nf_nat_local_fn(unsigned int hooknum,
 	return ret;
 }
 
-static unsigned int
-nf_nat_adjust(unsigned int hooknum,
-	      struct sk_buff *skb,
-	      const struct net_device *in,
-	      const struct net_device *out,
-	      int (*okfn)(struct sk_buff *))
-{
-	struct nf_conn *ct;
-	enum ip_conntrack_info ctinfo;
-
-	ct = nf_ct_get(skb, &ctinfo);
-	if (ct && test_bit(IPS_SEQ_ADJUST_BIT, &ct->status)) {
-		pr_debug("nf_nat_standalone: adjusting sequence number\n");
-		if (!nf_nat_seq_adjust(skb, ct, ctinfo))
-			return NF_DROP;
-	}
-	return NF_ACCEPT;
-}
-
 /* We must be after connection tracking and before packet filtering. */
 
 static struct nf_hook_ops nf_nat_ops[] __read_mostly = {
@@ -283,14 +264,6 @@ static struct nf_hook_ops nf_nat_ops[] __read_mostly = {
 		.hooknum	= NF_INET_POST_ROUTING,
 		.priority	= NF_IP_PRI_NAT_SRC,
 	},
-	/* After conntrack, adjust sequence number */
-	{
-		.hook		= nf_nat_adjust,
-		.owner		= THIS_MODULE,
-		.pf		= PF_INET,
-		.hooknum	= NF_INET_POST_ROUTING,
-		.priority	= NF_IP_PRI_NAT_SEQ_ADJUST,
-	},
 	/* Before packet filtering, change destination */
 	{
 		.hook		= nf_nat_local_fn,
@@ -307,14 +280,6 @@ static struct nf_hook_ops nf_nat_ops[] __read_mostly = {
 		.hooknum	= NF_INET_LOCAL_IN,
 		.priority	= NF_IP_PRI_NAT_SRC,
 	},
-	/* After conntrack, adjust sequence number */
-	{
-		.hook		= nf_nat_adjust,
-		.owner		= THIS_MODULE,
-		.pf		= PF_INET,
-		.hooknum	= NF_INET_LOCAL_IN,
-		.priority	= NF_IP_PRI_NAT_SEQ_ADJUST,
-	},
 };
 
 static int __init nf_nat_standalone_init(void)