netfilter: nft_ct: add notrack support

This patch adds notrack support.

I decided to add a new expression, given that this doesn't fit into the
existing set operation. Notrack doesn't need a source register, and an
hypothetical NFT_CT_NOTRACK key makes no sense since matching the
untracked state is done through NFT_CT_STATE.

I'm placing this new notrack expression into nft_ct.c, I think a single
module is too much.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2016-10-20 18:07:14 +02:00
parent 96d9f2a72c
commit 254432613c

View File

@ -1,5 +1,6 @@
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
* Copyright (c) 2016 Pablo Neira Ayuso <pablo@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@ -518,15 +519,61 @@ static struct nft_expr_type nft_ct_type __read_mostly = {
.owner = THIS_MODULE,
};
static void nft_notrack_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct sk_buff *skb = pkt->skb;
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
ct = nf_ct_get(pkt->skb, &ctinfo);
/* Previously seen (loopback or untracked)? Ignore. */
if (ct)
return;
ct = nf_ct_untracked_get();
atomic_inc(&ct->ct_general.use);
skb->nfct = &ct->ct_general;
skb->nfctinfo = IP_CT_NEW;
}
static struct nft_expr_type nft_notrack_type;
static const struct nft_expr_ops nft_notrack_ops = {
.type = &nft_notrack_type,
.size = NFT_EXPR_SIZE(0),
.eval = nft_notrack_eval,
};
static struct nft_expr_type nft_notrack_type __read_mostly = {
.name = "notrack",
.ops = &nft_notrack_ops,
.owner = THIS_MODULE,
};
static int __init nft_ct_module_init(void)
{
int err;
BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE > NFT_REG_SIZE);
return nft_register_expr(&nft_ct_type);
err = nft_register_expr(&nft_ct_type);
if (err < 0)
return err;
err = nft_register_expr(&nft_notrack_type);
if (err < 0)
goto err1;
return 0;
err1:
nft_unregister_expr(&nft_ct_type);
return err;
}
static void __exit nft_ct_module_exit(void)
{
nft_unregister_expr(&nft_notrack_type);
nft_unregister_expr(&nft_ct_type);
}
@ -536,3 +583,4 @@ module_exit(nft_ct_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("ct");
MODULE_ALIAS_NFT_EXPR("notrack");