1/*
 2 * IPv4 specific functions of netfilter core
 3 *
 4 * Rusty Russell (C) 2000 -- This code is GPL.
 5 * Patrick McHardy (C) 2006-2012
 6 */
 7#include <linux/kernel.h>
 8#include <linux/netfilter.h>
 9#include <linux/netfilter_ipv4.h>
10#include <linux/ip.h>
11#include <linux/skbuff.h>
12#include <linux/gfp.h>
13#include <linux/export.h>
14#include <net/route.h>
15#include <net/xfrm.h>
16#include <net/ip.h>
17#include <net/netfilter/nf_queue.h>
18
19/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
20int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_type)
21{
22	const struct iphdr *iph = ip_hdr(skb);
23	struct rtable *rt;
24	struct flowi4 fl4 = {};
25	__be32 saddr = iph->saddr;
26	const struct sock *sk = skb_to_full_sk(skb);
27	__u8 flags = sk ? inet_sk_flowi_flags(sk) : 0;
28	struct net_device *dev = skb_dst(skb)->dev;
 
29	unsigned int hh_len;
30
 
 
 
31	if (addr_type == RTN_UNSPEC)
32		addr_type = inet_addr_type_dev_table(net, dev, saddr);
33	if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST)
34		flags |= FLOWI_FLAG_ANYSRC;
35	else
36		saddr = 0;
37
38	/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
39	 * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook.
40	 */
41	fl4.daddr = iph->daddr;
42	fl4.saddr = saddr;
43	fl4.flowi4_tos = RT_TOS(iph->tos);
44	fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0;
45	if (!fl4.flowi4_oif)
46		fl4.flowi4_oif = l3mdev_master_ifindex(dev);
47	fl4.flowi4_mark = skb->mark;
48	fl4.flowi4_flags = flags;
 
49	rt = ip_route_output_key(net, &fl4);
50	if (IS_ERR(rt))
51		return PTR_ERR(rt);
52
53	/* Drop old route. */
54	skb_dst_drop(skb);
55	skb_dst_set(skb, &rt->dst);
56
57	if (skb_dst(skb)->error)
58		return skb_dst(skb)->error;
59
60#ifdef CONFIG_XFRM
61	if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
62	    xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
63		struct dst_entry *dst = skb_dst(skb);
64		skb_dst_set(skb, NULL);
65		dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0);
66		if (IS_ERR(dst))
67			return PTR_ERR(dst);
68		skb_dst_set(skb, dst);
69	}
70#endif
71
72	/* Change in oif may mean change in hh_len. */
73	hh_len = skb_dst(skb)->dev->hard_header_len;
74	if (skb_headroom(skb) < hh_len &&
75	    pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
76				0, GFP_ATOMIC))
77		return -ENOMEM;
78
79	return 0;
80}
81EXPORT_SYMBOL(ip_route_me_harder);
82
83int nf_ip_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
84		bool strict __always_unused)
85{
86	struct rtable *rt = ip_route_output_key(net, &fl->u.ip4);
87	if (IS_ERR(rt))
88		return PTR_ERR(rt);
89	*dst = &rt->dst;
90	return 0;
91}
92EXPORT_SYMBOL_GPL(nf_ip_route);

 1/*
 2 * IPv4 specific functions of netfilter core
 3 *
 4 * Rusty Russell (C) 2000 -- This code is GPL.
 5 * Patrick McHardy (C) 2006-2012
 6 */
 7#include <linux/kernel.h>
 8#include <linux/netfilter.h>
 9#include <linux/netfilter_ipv4.h>
10#include <linux/ip.h>
11#include <linux/skbuff.h>
12#include <linux/gfp.h>
13#include <linux/export.h>
14#include <net/route.h>
15#include <net/xfrm.h>
16#include <net/ip.h>
17#include <net/netfilter/nf_queue.h>
18
19/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
20int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, unsigned int addr_type)
21{
22	const struct iphdr *iph = ip_hdr(skb);
23	struct rtable *rt;
24	struct flowi4 fl4 = {};
25	__be32 saddr = iph->saddr;
26	__u8 flags;
 
27	struct net_device *dev = skb_dst(skb)->dev;
28	struct flow_keys flkeys;
29	unsigned int hh_len;
30
31	sk = sk_to_full_sk(sk);
32	flags = sk ? inet_sk_flowi_flags(sk) : 0;
33
34	if (addr_type == RTN_UNSPEC)
35		addr_type = inet_addr_type_dev_table(net, dev, saddr);
36	if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST)
37		flags |= FLOWI_FLAG_ANYSRC;
38	else
39		saddr = 0;
40
41	/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
42	 * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook.
43	 */
44	fl4.daddr = iph->daddr;
45	fl4.saddr = saddr;
46	fl4.flowi4_tos = RT_TOS(iph->tos);
47	fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0;
48	fl4.flowi4_l3mdev = l3mdev_master_ifindex(dev);
 
49	fl4.flowi4_mark = skb->mark;
50	fl4.flowi4_flags = flags;
51	fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys);
52	rt = ip_route_output_key(net, &fl4);
53	if (IS_ERR(rt))
54		return PTR_ERR(rt);
55
56	/* Drop old route. */
57	skb_dst_drop(skb);
58	skb_dst_set(skb, &rt->dst);
59
60	if (skb_dst(skb)->error)
61		return skb_dst(skb)->error;
62
63#ifdef CONFIG_XFRM
64	if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
65	    xfrm_decode_session(net, skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
66		struct dst_entry *dst = skb_dst(skb);
67		skb_dst_set(skb, NULL);
68		dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0);
69		if (IS_ERR(dst))
70			return PTR_ERR(dst);
71		skb_dst_set(skb, dst);
72	}
73#endif
74
75	/* Change in oif may mean change in hh_len. */
76	hh_len = skb_dst(skb)->dev->hard_header_len;
77	if (skb_headroom(skb) < hh_len &&
78	    pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)),
79				0, GFP_ATOMIC))
80		return -ENOMEM;
81
82	return 0;
83}
84EXPORT_SYMBOL(ip_route_me_harder);
85
86int nf_ip_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
87		bool strict __always_unused)
88{
89	struct rtable *rt = ip_route_output_key(net, &fl->u.ip4);
90	if (IS_ERR(rt))
91		return PTR_ERR(rt);
92	*dst = &rt->dst;
93	return 0;
94}
95EXPORT_SYMBOL_GPL(nf_ip_route);