![Pablo Neira Ayuso](/assets/img/avatar_default.png)
This patch partially reverts:
3d058d7
netfilter: rework user-space expectation helper support
that was applied during the 3.2 development cycle.
After this patch, the tree remains just like before patch bc01bef,
that initially added the preliminary infrastructure.
I decided to partially revert this patch because the approach
that I proposed to resolve this problem is broken in NAT setups.
Moreover, a new infrastructure will be submitted for the 3.3.x
development cycle that resolve the existing issues while
providing a neat solution.
Since nobody has been seriously using this infrastructure in
user-space, the removal of this feature should affect any know
FOSS project (to my knowledge).
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
177 lines
4 KiB
C
177 lines
4 KiB
C
/*
|
|
* Copyright (c) 2010 Patrick McHardy <kaber@trash.net>
|
|
*
|
|
* 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
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
#include <linux/module.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/netfilter_ipv4/ip_tables.h>
|
|
#include <linux/netfilter_ipv6/ip6_tables.h>
|
|
#include <linux/netfilter/x_tables.h>
|
|
#include <linux/netfilter/xt_CT.h>
|
|
#include <net/netfilter/nf_conntrack.h>
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
#include <net/netfilter/nf_conntrack_ecache.h>
|
|
#include <net/netfilter/nf_conntrack_zones.h>
|
|
|
|
static unsigned int xt_ct_target(struct sk_buff *skb,
|
|
const struct xt_action_param *par)
|
|
{
|
|
const struct xt_ct_target_info *info = par->targinfo;
|
|
struct nf_conn *ct = info->ct;
|
|
|
|
/* Previously seen (loopback)? Ignore. */
|
|
if (skb->nfct != NULL)
|
|
return XT_CONTINUE;
|
|
|
|
atomic_inc(&ct->ct_general.use);
|
|
skb->nfct = &ct->ct_general;
|
|
skb->nfctinfo = IP_CT_NEW;
|
|
|
|
return XT_CONTINUE;
|
|
}
|
|
|
|
static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
|
|
{
|
|
if (par->family == NFPROTO_IPV4) {
|
|
const struct ipt_entry *e = par->entryinfo;
|
|
|
|
if (e->ip.invflags & IPT_INV_PROTO)
|
|
return 0;
|
|
return e->ip.proto;
|
|
} else if (par->family == NFPROTO_IPV6) {
|
|
const struct ip6t_entry *e = par->entryinfo;
|
|
|
|
if (e->ipv6.invflags & IP6T_INV_PROTO)
|
|
return 0;
|
|
return e->ipv6.proto;
|
|
} else
|
|
return 0;
|
|
}
|
|
|
|
static int xt_ct_tg_check(const struct xt_tgchk_param *par)
|
|
{
|
|
struct xt_ct_target_info *info = par->targinfo;
|
|
struct nf_conntrack_tuple t;
|
|
struct nf_conn_help *help;
|
|
struct nf_conn *ct;
|
|
int ret = 0;
|
|
u8 proto;
|
|
|
|
if (info->flags & ~XT_CT_NOTRACK)
|
|
return -EINVAL;
|
|
|
|
if (info->flags & XT_CT_NOTRACK) {
|
|
ct = nf_ct_untracked_get();
|
|
atomic_inc(&ct->ct_general.use);
|
|
goto out;
|
|
}
|
|
|
|
#ifndef CONFIG_NF_CONNTRACK_ZONES
|
|
if (info->zone)
|
|
goto err1;
|
|
#endif
|
|
|
|
ret = nf_ct_l3proto_try_module_get(par->family);
|
|
if (ret < 0)
|
|
goto err1;
|
|
|
|
memset(&t, 0, sizeof(t));
|
|
ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
|
|
ret = PTR_ERR(ct);
|
|
if (IS_ERR(ct))
|
|
goto err2;
|
|
|
|
ret = 0;
|
|
if ((info->ct_events || info->exp_events) &&
|
|
!nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
|
|
GFP_KERNEL))
|
|
goto err3;
|
|
|
|
if (info->helper[0]) {
|
|
ret = -ENOENT;
|
|
proto = xt_ct_find_proto(par);
|
|
if (!proto) {
|
|
pr_info("You must specify a L4 protocol, "
|
|
"and not use inversions on it.\n");
|
|
goto err3;
|
|
}
|
|
|
|
ret = -ENOMEM;
|
|
help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
|
|
if (help == NULL)
|
|
goto err3;
|
|
|
|
ret = -ENOENT;
|
|
help->helper = nf_conntrack_helper_try_module_get(info->helper,
|
|
par->family,
|
|
proto);
|
|
if (help->helper == NULL) {
|
|
pr_info("No such helper \"%s\"\n", info->helper);
|
|
goto err3;
|
|
}
|
|
}
|
|
|
|
__set_bit(IPS_TEMPLATE_BIT, &ct->status);
|
|
__set_bit(IPS_CONFIRMED_BIT, &ct->status);
|
|
out:
|
|
info->ct = ct;
|
|
return 0;
|
|
|
|
err3:
|
|
nf_conntrack_free(ct);
|
|
err2:
|
|
nf_ct_l3proto_module_put(par->family);
|
|
err1:
|
|
return ret;
|
|
}
|
|
|
|
static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par)
|
|
{
|
|
struct xt_ct_target_info *info = par->targinfo;
|
|
struct nf_conn *ct = info->ct;
|
|
struct nf_conn_help *help;
|
|
|
|
if (!nf_ct_is_untracked(ct)) {
|
|
help = nfct_help(ct);
|
|
if (help)
|
|
module_put(help->helper->me);
|
|
|
|
nf_ct_l3proto_module_put(par->family);
|
|
}
|
|
nf_ct_put(info->ct);
|
|
}
|
|
|
|
static struct xt_target xt_ct_tg __read_mostly = {
|
|
.name = "CT",
|
|
.family = NFPROTO_UNSPEC,
|
|
.targetsize = sizeof(struct xt_ct_target_info),
|
|
.checkentry = xt_ct_tg_check,
|
|
.destroy = xt_ct_tg_destroy,
|
|
.target = xt_ct_target,
|
|
.table = "raw",
|
|
.me = THIS_MODULE,
|
|
};
|
|
|
|
static int __init xt_ct_tg_init(void)
|
|
{
|
|
return xt_register_target(&xt_ct_tg);
|
|
}
|
|
|
|
static void __exit xt_ct_tg_exit(void)
|
|
{
|
|
xt_unregister_target(&xt_ct_tg);
|
|
}
|
|
|
|
module_init(xt_ct_tg_init);
|
|
module_exit(xt_ct_tg_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Xtables: connection tracking target");
|
|
MODULE_ALIAS("ipt_CT");
|
|
MODULE_ALIAS("ip6t_CT");
|