netfilter: ip_tables: pass table pointer via nf_hook_ops

iptable_x modules rely on 'struct net' to contain a pointer to the
table that should be evaluated.

In order to remove these pointers from struct net, pass them via
the 'priv' pointer in a similar fashion as nf_tables passes the
rule data.

To do that, duplicate the nf_hook_info array passed in from the
iptable_x modules, update the ops->priv pointers of the copy to
refer to the table and then change the hookfn implementations to
just pass the 'priv' argument to the traverser.

After this patch, the xt_table pointers can already be removed
from struct net.

However, changes to struct net result in re-compile of the entire
network stack, so do the removal after arptables and ip6tables
have been converted as well.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 6 insertions, 8 deletions

diff --git a/net/ipv4/netfilter/iptable_mangle.c b/net/ipv4/netfilter/iptable_mangle.c
index 98e9e9053d85..2abc3836f391 100644
--- a/net/ipv4/netfilter/iptable_mangle.c
+++ b/net/ipv4/netfilter/iptable_mangle.c
@@ -37,7 +37,7 @@ static const struct xt_table packet_mangler = {
 };
 
 static unsigned int
-ipt_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
+ipt_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state, void *priv)
 {
 	unsigned int ret;
 	const struct iphdr *iph;
@@ -53,7 +53,7 @@ ipt_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
 	daddr = iph->daddr;
 	tos = iph->tos;
 
-	ret = ipt_do_table(skb, state, state->net->ipv4.iptable_mangle);
+	ret = ipt_do_table(skb, state, priv);
 	/* Reroute for ANY change. */
 	if (ret != NF_DROP && ret != NF_STOLEN) {
 		iph = ip_hdr(skb);
@@ -78,8 +78,8 @@ iptable_mangle_hook(void *priv,
 		     const struct nf_hook_state *state)
 {
 	if (state->hook == NF_INET_LOCAL_OUT)
-		return ipt_mangle_out(skb, state);
-	return ipt_do_table(skb, state, state->net->ipv4.iptable_mangle);
+		return ipt_mangle_out(skb, state, priv);
+	return ipt_do_table(skb, state, priv);
 }
 
 static struct nf_hook_ops *mangle_ops __read_mostly;
@@ -91,21 +91,19 @@ static int __net_init iptable_mangle_table_init(struct net *net)
 	repl = ipt_alloc_initial_table(&packet_mangler);
 	if (repl == NULL)
 		return -ENOMEM;
-	ret = ipt_register_table(net, &packet_mangler, repl, mangle_ops,
-				 &net->ipv4.iptable_mangle);
+	ret = ipt_register_table(net, &packet_mangler, repl, mangle_ops);
 	kfree(repl);
 	return ret;
 }
 
 static void __net_exit iptable_mangle_net_pre_exit(struct net *net)
 {
-	ipt_unregister_table_pre_exit(net, "mangle", mangle_ops);
+	ipt_unregister_table_pre_exit(net, "mangle");
 }
 
 static void __net_exit iptable_mangle_net_exit(struct net *net)
 {
 	ipt_unregister_table_exit(net, "mangle");
-	net->ipv4.iptable_mangle = NULL;
 }
 
 static struct pernet_operations iptable_mangle_net_ops = {