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authorFlorian Westphal <fw@strlen.de>2021-04-21 09:51:06 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2021-04-26 03:20:46 +0200
commita4aeafa28cf706f65f763026c26d83e7e8c96592 (patch)
tree808792a718e5aca1edb6cef236622bd8094eb751 /net/ipv4/netfilter
parentf68772ed678376f52dbb2e20c9f982e6d8b3407b (diff)
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>
Diffstat (limited to 'net/ipv4/netfilter')
-rw-r--r--net/ipv4/netfilter/iptable_nat.c44
1 files changed, 34 insertions, 10 deletions
diff --git a/net/ipv4/netfilter/iptable_nat.c b/net/ipv4/netfilter/iptable_nat.c
index f4afd28ccc06..dfa9dc63a7b5 100644
--- 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)