mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-22 17:01:14 +00:00
![Jiri Pirko](/assets/img/avatar_default.png)
Pushing original fragments through causes several problems. For example for matching, frags may not be matched correctly. Take following example: <example> On HOSTA do: ip6tables -I INPUT -p icmpv6 -j DROP ip6tables -I INPUT -p icmpv6 -m icmp6 --icmpv6-type 128 -j ACCEPT and on HOSTB you do: ping6 HOSTA -s2000 (MTU is 1500) Incoming echo requests will be filtered out on HOSTA. This issue does not occur with smaller packets than MTU (where fragmentation does not happen) </example> As was discussed previously, the only correct solution seems to be to use reassembled skb instead of separete frags. Doing this has positive side effects in reducing sk_buff by one pointer (nfct_reasm) and also the reams dances in ipvs and conntrack can be removed. Future plan is to remove net/ipv6/netfilter/nf_conntrack_reasm.c entirely and use code in net/ipv6/reassembly.c instead. Signed-off-by: Jiri Pirko <jiri@resnulli.us> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Marcelo Ricardo Leitner <mleitner@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
140 lines
3.4 KiB
C
140 lines
3.4 KiB
C
/* (C) 1999-2001 Paul `Rusty' Russell
|
|
* (C) 2002-2004 Netfilter Core Team <coreteam@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
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/ipv6.h>
|
|
#include <linux/in6.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/module.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/icmp.h>
|
|
#include <linux/sysctl.h>
|
|
#include <net/ipv6.h>
|
|
#include <net/inet_frag.h>
|
|
|
|
#include <linux/netfilter_ipv6.h>
|
|
#include <linux/netfilter_bridge.h>
|
|
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
|
|
#include <net/netfilter/nf_conntrack.h>
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
#include <net/netfilter/nf_conntrack_l4proto.h>
|
|
#include <net/netfilter/nf_conntrack_l3proto.h>
|
|
#include <net/netfilter/nf_conntrack_core.h>
|
|
#include <net/netfilter/ipv6/nf_conntrack_ipv6.h>
|
|
#endif
|
|
#include <net/netfilter/nf_conntrack_zones.h>
|
|
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
|
|
|
|
static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
|
|
struct sk_buff *skb)
|
|
{
|
|
u16 zone = NF_CT_DEFAULT_ZONE;
|
|
|
|
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
|
|
if (skb->nfct)
|
|
zone = nf_ct_zone((struct nf_conn *)skb->nfct);
|
|
#endif
|
|
|
|
#ifdef CONFIG_BRIDGE_NETFILTER
|
|
if (skb->nf_bridge &&
|
|
skb->nf_bridge->mask & BRNF_NF_BRIDGE_PREROUTING)
|
|
return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone;
|
|
#endif
|
|
if (hooknum == NF_INET_PRE_ROUTING)
|
|
return IP6_DEFRAG_CONNTRACK_IN + zone;
|
|
else
|
|
return IP6_DEFRAG_CONNTRACK_OUT + zone;
|
|
|
|
}
|
|
|
|
static unsigned int ipv6_defrag(const struct nf_hook_ops *ops,
|
|
struct sk_buff *skb,
|
|
const struct net_device *in,
|
|
const struct net_device *out,
|
|
int (*okfn)(struct sk_buff *))
|
|
{
|
|
struct sk_buff *reasm;
|
|
|
|
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
|
|
/* Previously seen (loopback)? */
|
|
if (skb->nfct && !nf_ct_is_template((struct nf_conn *)skb->nfct))
|
|
return NF_ACCEPT;
|
|
#endif
|
|
|
|
reasm = nf_ct_frag6_gather(skb, nf_ct6_defrag_user(ops->hooknum, skb));
|
|
/* queued */
|
|
if (reasm == NULL)
|
|
return NF_STOLEN;
|
|
|
|
/* error occurred or not fragmented */
|
|
if (reasm == skb)
|
|
return NF_ACCEPT;
|
|
|
|
nf_ct_frag6_consume_orig(reasm);
|
|
|
|
NF_HOOK_THRESH(NFPROTO_IPV6, ops->hooknum, reasm,
|
|
(struct net_device *) in, (struct net_device *) out,
|
|
okfn, NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
|
|
|
|
return NF_STOLEN;
|
|
}
|
|
|
|
static struct nf_hook_ops ipv6_defrag_ops[] = {
|
|
{
|
|
.hook = ipv6_defrag,
|
|
.owner = THIS_MODULE,
|
|
.pf = NFPROTO_IPV6,
|
|
.hooknum = NF_INET_PRE_ROUTING,
|
|
.priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
|
|
},
|
|
{
|
|
.hook = ipv6_defrag,
|
|
.owner = THIS_MODULE,
|
|
.pf = NFPROTO_IPV6,
|
|
.hooknum = NF_INET_LOCAL_OUT,
|
|
.priority = NF_IP6_PRI_CONNTRACK_DEFRAG,
|
|
},
|
|
};
|
|
|
|
static int __init nf_defrag_init(void)
|
|
{
|
|
int ret = 0;
|
|
|
|
ret = nf_ct_frag6_init();
|
|
if (ret < 0) {
|
|
pr_err("nf_defrag_ipv6: can't initialize frag6.\n");
|
|
return ret;
|
|
}
|
|
ret = nf_register_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
|
|
if (ret < 0) {
|
|
pr_err("nf_defrag_ipv6: can't register hooks\n");
|
|
goto cleanup_frag6;
|
|
}
|
|
return ret;
|
|
|
|
cleanup_frag6:
|
|
nf_ct_frag6_cleanup();
|
|
return ret;
|
|
|
|
}
|
|
|
|
static void __exit nf_defrag_fini(void)
|
|
{
|
|
nf_unregister_hooks(ipv6_defrag_ops, ARRAY_SIZE(ipv6_defrag_ops));
|
|
nf_ct_frag6_cleanup();
|
|
}
|
|
|
|
void nf_defrag_ipv6_enable(void)
|
|
{
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_defrag_ipv6_enable);
|
|
|
|
module_init(nf_defrag_init);
|
|
module_exit(nf_defrag_fini);
|
|
|
|
MODULE_LICENSE("GPL");
|