95 строки
2.5 KiB
C
95 строки
2.5 KiB
C
/*
|
|
* IPv4 specific functions of netfilter core
|
|
*
|
|
* Rusty Russell (C) 2000 -- This code is GPL.
|
|
* Patrick McHardy (C) 2006-2012
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/netfilter.h>
|
|
#include <linux/netfilter_ipv4.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/export.h>
|
|
#include <net/route.h>
|
|
#include <net/xfrm.h>
|
|
#include <net/ip.h>
|
|
#include <net/netfilter/nf_queue.h>
|
|
|
|
/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
|
|
int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, unsigned int addr_type)
|
|
{
|
|
const struct iphdr *iph = ip_hdr(skb);
|
|
struct rtable *rt;
|
|
struct flowi4 fl4 = {};
|
|
__be32 saddr = iph->saddr;
|
|
__u8 flags;
|
|
struct net_device *dev = skb_dst(skb)->dev;
|
|
unsigned int hh_len;
|
|
|
|
sk = sk_to_full_sk(sk);
|
|
flags = sk ? inet_sk_flowi_flags(sk) : 0;
|
|
|
|
if (addr_type == RTN_UNSPEC)
|
|
addr_type = inet_addr_type_dev_table(net, dev, saddr);
|
|
if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST)
|
|
flags |= FLOWI_FLAG_ANYSRC;
|
|
else
|
|
saddr = 0;
|
|
|
|
/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
|
|
* packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook.
|
|
*/
|
|
fl4.daddr = iph->daddr;
|
|
fl4.saddr = saddr;
|
|
fl4.flowi4_tos = RT_TOS(iph->tos);
|
|
fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0;
|
|
if (!fl4.flowi4_oif)
|
|
fl4.flowi4_oif = l3mdev_master_ifindex(dev);
|
|
fl4.flowi4_mark = skb->mark;
|
|
fl4.flowi4_flags = flags;
|
|
rt = ip_route_output_key(net, &fl4);
|
|
if (IS_ERR(rt))
|
|
return PTR_ERR(rt);
|
|
|
|
/* Drop old route. */
|
|
skb_dst_drop(skb);
|
|
skb_dst_set(skb, &rt->dst);
|
|
|
|
if (skb_dst(skb)->error)
|
|
return skb_dst(skb)->error;
|
|
|
|
#ifdef CONFIG_XFRM
|
|
if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
|
|
xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
|
|
struct dst_entry *dst = skb_dst(skb);
|
|
skb_dst_set(skb, NULL);
|
|
dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0);
|
|
if (IS_ERR(dst))
|
|
return PTR_ERR(dst);
|
|
skb_dst_set(skb, dst);
|
|
}
|
|
#endif
|
|
|
|
/* Change in oif may mean change in hh_len. */
|
|
hh_len = skb_dst(skb)->dev->hard_header_len;
|
|
if (skb_headroom(skb) < hh_len &&
|
|
pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
|
|
0, GFP_ATOMIC))
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(ip_route_me_harder);
|
|
|
|
int nf_ip_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
|
|
bool strict __always_unused)
|
|
{
|
|
struct rtable *rt = ip_route_output_key(net, &fl->u.ip4);
|
|
if (IS_ERR(rt))
|
|
return PTR_ERR(rt);
|
|
*dst = &rt->dst;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(nf_ip_route);
|