1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/*
* Copyright (c) 2008 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.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/route.h>
#include <net/ip.h>
static unsigned int nf_route_table_hook(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 *))
{
unsigned int ret;
u32 mark;
__be32 saddr, daddr;
u_int8_t tos;
const struct iphdr *iph;
/* root is playing with raw sockets. */
if (skb->len < sizeof(struct iphdr) ||
ip_hdrlen(skb) < sizeof(struct iphdr))
return NF_ACCEPT;
mark = skb->mark;
iph = ip_hdr(skb);
saddr = iph->saddr;
daddr = iph->daddr;
tos = iph->tos;
ret = nft_do_chain(ops, skb, in, out, okfn);
if (ret != NF_DROP && ret != NF_QUEUE) {
iph = ip_hdr(skb);
if (iph->saddr != saddr ||
iph->daddr != daddr ||
skb->mark != mark ||
iph->tos != tos)
if (ip_route_me_harder(skb, RTN_UNSPEC))
ret = NF_DROP;
}
return ret;
}
static struct nft_base_chain nf_chain_route_output __read_mostly = {
.chain = {
.name = "OUTPUT",
.rules = LIST_HEAD_INIT(nf_chain_route_output.chain.rules),
.flags = NFT_BASE_CHAIN | NFT_CHAIN_BUILTIN,
},
.ops = {
.hook = nf_route_table_hook,
.owner = THIS_MODULE,
.pf = NFPROTO_IPV4,
.hooknum = NF_INET_LOCAL_OUT,
.priority = NF_IP_PRI_MANGLE,
.priv = &nf_chain_route_output.chain,
},
};
static struct nft_table nf_table_route_ipv4 __read_mostly = {
.name = "route",
.chains = LIST_HEAD_INIT(nf_table_route_ipv4.chains),
};
static int __init nf_table_route_init(void)
{
list_add_tail(&nf_chain_route_output.chain.list,
&nf_table_route_ipv4.chains);
return nft_register_table(&nf_table_route_ipv4, NFPROTO_IPV4);
}
static void __exit nf_table_route_exit(void)
{
nft_unregister_table(&nf_table_route_ipv4, NFPROTO_IPV4);
}
module_init(nf_table_route_init);
module_exit(nf_table_route_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_TABLE(AF_INET, "route");
|