netfilter: xt_nat: pass table to hookfn

This changes how ip(6)table nat passes the ruleset/table to the
evaluation loop.

At the moment, it will fetch the table from struct net.

This change stores the table in the hook_ops 'priv' argument
instead.

This requires to duplicate the hook_ops for each netns, so
they can store the (per-net) xt_table structure.

The dupliated nat hook_ops get stored in net_generic data area.
They are free'd in the namespace exit path.

This is a pre-requisite to remove the xt_table/ruleset pointers
from struct net.

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

diff --git a/net/ipv4/netfilter/iptable_nat.c b/net/ipv4/netfilter/iptable_nat.c
index f4afd28..dfa9dc6 100644 (file)
--- a/net/ipv4/netfilter/iptable_nat.c
+++ b/net/ipv4/netfilter/iptable_nat.c
@@ -13,8 +13,14 @@
 
 #include <net/netfilter/nf_nat.h>
 
+struct iptable_nat_pernet {
+       struct nf_hook_ops *nf_nat_ops;
+};
+
 static int __net_init iptable_nat_table_init(struct net *net);
 
+static unsigned int iptable_nat_net_id __read_mostly;
+
 static const struct xt_table nf_nat_ipv4_table = {
        .name           = "nat",
        .valid_hooks    = (1 << NF_INET_PRE_ROUTING) |
@@ -30,7 +36,7 @@ static unsigned int iptable_nat_do_chain(void *priv,
                                         struct sk_buff *skb,
                                         const struct nf_hook_state *state)
 {
-       return ipt_do_table(skb, state, state->net->ipv4.nat_table);
+       return ipt_do_table(skb, state, priv);
 }
 
 static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
@@ -60,50 +66,67 @@ static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
        },
 };
 
-static int ipt_nat_register_lookups(struct net *net)
+static int ipt_nat_register_lookups(struct net *net, struct xt_table *table)
 {
+       struct nf_hook_ops *ops = kmemdup(nf_nat_ipv4_ops, sizeof(nf_nat_ipv4_ops), GFP_KERNEL);
+       struct iptable_nat_pernet *xt_nat_net = net_generic(net, iptable_nat_net_id);
        int i, ret;
 
+       if (!ops)
+               return -ENOMEM;
+
        for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) {
-               ret = nf_nat_ipv4_register_fn(net, &nf_nat_ipv4_ops[i]);
+               ops[i].priv = table;
+               ret = nf_nat_ipv4_register_fn(net, &ops[i]);
                if (ret) {
                        while (i)
-                               nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[--i]);
+                               nf_nat_ipv4_unregister_fn(net, &ops[--i]);
 
+                       kfree(ops);
                        return ret;
                }
        }
 
+       xt_nat_net->nf_nat_ops = ops;
        return 0;
 }
 
 static void ipt_nat_unregister_lookups(struct net *net)
 {
+       struct iptable_nat_pernet *xt_nat_net = net_generic(net, iptable_nat_net_id);
+       struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops;
        int i;
 
+       if (!ops)
+               return;
+
        for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++)
-               nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[i]);
+               nf_nat_ipv4_unregister_fn(net, &ops[i]);
+
+       kfree(ops);
 }
 
 static int __net_init iptable_nat_table_init(struct net *net)
 {
        struct ipt_replace *repl;
+       struct xt_table *table;
        int ret;
 
        repl = ipt_alloc_initial_table(&nf_nat_ipv4_table);
        if (repl == NULL)
                return -ENOMEM;
        ret = ipt_register_table(net, &nf_nat_ipv4_table, repl,
-                                NULL, &net->ipv4.nat_table);
+                                NULL, &table);
        if (ret < 0) {
                kfree(repl);
                return ret;
        }
 
-       ret = ipt_nat_register_lookups(net);
+       ret = ipt_nat_register_lookups(net, table);
        if (ret < 0) {
                ipt_unregister_table_exit(net, "nat");
-               net->ipv4.nat_table = NULL;
+       } else {
+               net->ipv4.nat_table = table;
        }
 
        kfree(repl);
@@ -112,8 +135,7 @@ static int __net_init iptable_nat_table_init(struct net *net)
 
 static void __net_exit iptable_nat_net_pre_exit(struct net *net)
 {
-       if (net->ipv4.nat_table)
-               ipt_nat_unregister_lookups(net);
+       ipt_nat_unregister_lookups(net);
 }
 
 static void __net_exit iptable_nat_net_exit(struct net *net)
@@ -125,6 +147,8 @@ static void __net_exit iptable_nat_net_exit(struct net *net)
 static struct pernet_operations iptable_nat_net_ops = {
        .pre_exit = iptable_nat_net_pre_exit,
        .exit   = iptable_nat_net_exit,
+       .id     = &iptable_nat_net_id,
+       .size   = sizeof(struct iptable_nat_pernet),
 };
 
 static int __init iptable_nat_init(void)

diff --git a/net/ipv6/netfilter/ip6table_nat.c b/net/ipv6/netfilter/ip6table_nat.c
index c7f9875..69b7f96 100644 (file)
--- a/net/ipv6/netfilter/ip6table_nat.c
+++ b/net/ipv6/netfilter/ip6table_nat.c
@@ -15,8 +15,14 @@
 
 #include <net/netfilter/nf_nat.h>
 
+struct ip6table_nat_pernet {
+       struct nf_hook_ops *nf_nat_ops;
+};
+
 static int __net_init ip6table_nat_table_init(struct net *net);
 
+static unsigned int ip6table_nat_net_id __read_mostly;
+
 static const struct xt_table nf_nat_ipv6_table = {
        .name           = "nat",
        .valid_hooks    = (1 << NF_INET_PRE_ROUTING) |
@@ -32,7 +38,7 @@ static unsigned int ip6table_nat_do_chain(void *priv,
                                          struct sk_buff *skb,
                                          const struct nf_hook_state *state)
 {
-       return ip6t_do_table(skb, state, state->net->ipv6.ip6table_nat);
+       return ip6t_do_table(skb, state, priv);
 }
 
 static const struct nf_hook_ops nf_nat_ipv6_ops[] = {
@@ -62,59 +68,76 @@ static const struct nf_hook_ops nf_nat_ipv6_ops[] = {
        },
 };
 
-static int ip6t_nat_register_lookups(struct net *net)
+static int ip6t_nat_register_lookups(struct net *net, struct xt_table *table)
 {
+       struct nf_hook_ops *ops = kmemdup(nf_nat_ipv6_ops, sizeof(nf_nat_ipv6_ops), GFP_KERNEL);
+       struct ip6table_nat_pernet *xt_nat_net = net_generic(net, ip6table_nat_net_id);
        int i, ret;
 
+       if (!ops)
+               return -ENOMEM;
+
        for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++) {
-               ret = nf_nat_ipv6_register_fn(net, &nf_nat_ipv6_ops[i]);
+               ops[i].priv = table;
+               ret = nf_nat_ipv6_register_fn(net, &ops[i]);
                if (ret) {
                        while (i)
-                               nf_nat_ipv6_unregister_fn(net, &nf_nat_ipv6_ops[--i]);
+                               nf_nat_ipv6_unregister_fn(net, &ops[--i]);
 
+                       kfree(ops);
                        return ret;
                }
        }
 
+       xt_nat_net->nf_nat_ops = ops;
        return 0;
 }
 
 static void ip6t_nat_unregister_lookups(struct net *net)
 {
+       struct ip6table_nat_pernet *xt_nat_net = net_generic(net, ip6table_nat_net_id);
+       struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops;
        int i;
 
+       if (!ops)
+               return;
+
        for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++)
-               nf_nat_ipv6_unregister_fn(net, &nf_nat_ipv6_ops[i]);
+               nf_nat_ipv6_unregister_fn(net, &ops[i]);
+
+       kfree(ops);
 }
 
 static int __net_init ip6table_nat_table_init(struct net *net)
 {
        struct ip6t_replace *repl;
+       struct xt_table *table;
        int ret;
 
        repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table);
        if (repl == NULL)
                return -ENOMEM;
        ret = ip6t_register_table(net, &nf_nat_ipv6_table, repl,
-                                 NULL, &net->ipv6.ip6table_nat);
+                                 NULL, &table);
        if (ret < 0) {
                kfree(repl);
                return ret;
        }
 
-       ret = ip6t_nat_register_lookups(net);
+       ret = ip6t_nat_register_lookups(net, table);
        if (ret < 0) {
                ip6t_unregister_table_exit(net, "nat");
-               net->ipv6.ip6table_nat = NULL;
+       } else {
+               net->ipv6.ip6table_nat = table;
        }
+
        kfree(repl);
        return ret;
 }
 
 static void __net_exit ip6table_nat_net_pre_exit(struct net *net)
 {
-       if (net->ipv6.ip6table_nat)
-               ip6t_nat_unregister_lookups(net);
+       ip6t_nat_unregister_lookups(net);
 }
 
 static void __net_exit ip6table_nat_net_exit(struct net *net)
@@ -126,6 +149,8 @@ static void __net_exit ip6table_nat_net_exit(struct net *net)
 static struct pernet_operations ip6table_nat_net_ops = {
        .pre_exit = ip6table_nat_net_pre_exit,
        .exit   = ip6table_nat_net_exit,
+       .id     = &ip6table_nat_net_id,
+       .size   = sizeof(struct ip6table_nat_pernet),
 };
 
 static int __init ip6table_nat_init(void)