[net-next-2.6.git] / net / ipv4 / netfilter.c

/* IPv4 specific functions of netfilter core */

#include <linux/config.h>
#ifdef CONFIG_NETFILTER

#include <linux/kernel.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>

#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <net/route.h>
#include <net/xfrm.h>
#include <net/ip.h>

/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
int ip_route_me_harder(struct sk_buff **pskb)
{
	struct iphdr *iph = (*pskb)->nh.iph;
	struct rtable *rt;
	struct flowi fl = {};
	struct dst_entry *odst;
	unsigned int hh_len;

	/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
	 * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook.
	 */
	if (inet_addr_type(iph->saddr) == RTN_LOCAL) {
		fl.nl_u.ip4_u.daddr = iph->daddr;
		fl.nl_u.ip4_u.saddr = iph->saddr;
		fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
		fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0;
#ifdef CONFIG_IP_ROUTE_FWMARK
		fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark;
#endif
		if (ip_route_output_key(&rt, &fl) != 0)
			return -1;

		/* Drop old route. */
		dst_release((*pskb)->dst);
		(*pskb)->dst = &rt->u.dst;
	} else {
		/* non-local src, find valid iif to satisfy
		 * rp-filter when calling ip_route_input. */
		fl.nl_u.ip4_u.daddr = iph->saddr;
		if (ip_route_output_key(&rt, &fl) != 0)
			return -1;

		odst = (*pskb)->dst;
		if (ip_route_input(*pskb, iph->daddr, iph->saddr,
				   RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
			dst_release(&rt->u.dst);
			return -1;
		}
		dst_release(&rt->u.dst);
		dst_release(odst);
	}
	
	if ((*pskb)->dst->error)
		return -1;

#ifdef CONFIG_XFRM
	if (!(IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED) &&
	    xfrm_decode_session(*pskb, &fl, AF_INET) == 0)
		if (xfrm_lookup(&(*pskb)->dst, &fl, (*pskb)->sk, 0))
			return -1;
#endif

	/* Change in oif may mean change in hh_len. */
	hh_len = (*pskb)->dst->dev->hard_header_len;
	if (skb_headroom(*pskb) < hh_len) {
		struct sk_buff *nskb;

		nskb = skb_realloc_headroom(*pskb, hh_len);
		if (!nskb) 
			return -1;
		if ((*pskb)->sk)
			skb_set_owner_w(nskb, (*pskb)->sk);
		kfree_skb(*pskb);
		*pskb = nskb;
	}

	return 0;
}
EXPORT_SYMBOL(ip_route_me_harder);

/*
 * Extra routing may needed on local out, as the QUEUE target never
 * returns control to the table.
 */

struct ip_rt_info {
	u_int32_t daddr;
	u_int32_t saddr;
	u_int8_t tos;
};

static void queue_save(const struct sk_buff *skb, struct nf_info *info)
{
	struct ip_rt_info *rt_info = nf_info_reroute(info);

	if (info->hook == NF_IP_LOCAL_OUT) {
		const struct iphdr *iph = skb->nh.iph;

		rt_info->tos = iph->tos;
		rt_info->daddr = iph->daddr;
		rt_info->saddr = iph->saddr;
	}
}

static int queue_reroute(struct sk_buff **pskb, const struct nf_info *info)
{
	const struct ip_rt_info *rt_info = nf_info_reroute(info);

	if (info->hook == NF_IP_LOCAL_OUT) {
		struct iphdr *iph = (*pskb)->nh.iph;

		if (!(iph->tos == rt_info->tos
		      && iph->daddr == rt_info->daddr
		      && iph->saddr == rt_info->saddr))
			return ip_route_me_harder(pskb);
	}
	return 0;
}

static struct nf_queue_rerouter ip_reroute = {
	.rer_size	= sizeof(struct ip_rt_info),
	.save		= queue_save,
	.reroute	= queue_reroute,
};

static int init(void)
{
	return nf_register_queue_rerouter(PF_INET, &ip_reroute);
}

static void fini(void)
{
	nf_unregister_queue_rerouter(PF_INET);
}

module_init(init);
module_exit(fini);

#endif /* CONFIG_NETFILTER */
Commit	Line	Data
2cc7d573	1	/* IPv4 specific functions of netfilter core */
020b4c12	2
2cc7d573	3	#include <linux/config.h>
020b4c12 HW	4	#ifdef CONFIG_NETFILTER
020b4c12 HW	5
020b4c12 HW	6	#include <linux/kernel.h>
020b4c12 HW	7	#include <linux/netfilter.h>
2cc7d573	8	#include <linux/netfilter_ipv4.h>
020b4c12	9
3e3850e9	10	#include <linux/ip.h>
020b4c12 HW	11	#include <linux/tcp.h>
	12	#include <linux/udp.h>
	13	#include <linux/icmp.h>
	14	#include <net/route.h>
3e3850e9 PM	15	#include <net/xfrm.h>
3e3850e9 PM	16	#include <net/ip.h>
020b4c12 HW	17
	18	/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
	19	int ip_route_me_harder(struct sk_buff **pskb)
	20	{
	21	struct iphdr iph = (pskb)->nh.iph;
	22	struct rtable *rt;
	23	struct flowi fl = {};
	24	struct dst_entry *odst;
	25	unsigned int hh_len;
	26
	27	/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
	28	* packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook.
	29	*/
	30	if (inet_addr_type(iph->saddr) == RTN_LOCAL) {
	31	fl.nl_u.ip4_u.daddr = iph->daddr;
	32	fl.nl_u.ip4_u.saddr = iph->saddr;
	33	fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
	34	fl.oif = (pskb)->sk ? (pskb)->sk->sk_bound_dev_if : 0;
	35	#ifdef CONFIG_IP_ROUTE_FWMARK
	36	fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark;
	37	#endif
020b4c12 HW	38	if (ip_route_output_key(&rt, &fl) != 0)
	39	return -1;
	40
	41	/* Drop old route. */
	42	dst_release((*pskb)->dst);
	43	(*pskb)->dst = &rt->u.dst;
	44	} else {
	45	/* non-local src, find valid iif to satisfy
	46	* rp-filter when calling ip_route_input. */
	47	fl.nl_u.ip4_u.daddr = iph->saddr;
	48	if (ip_route_output_key(&rt, &fl) != 0)
	49	return -1;
	50
	51	odst = (*pskb)->dst;
	52	if (ip_route_input(*pskb, iph->daddr, iph->saddr,
	53	RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
	54	dst_release(&rt->u.dst);
	55	return -1;
	56	}
	57	dst_release(&rt->u.dst);
	58	dst_release(odst);
	59	}
	60
	61	if ((*pskb)->dst->error)
	62	return -1;
	63
3e3850e9 PM	64	#ifdef CONFIG_XFRM
	65	if (!(IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED) &&
	66	xfrm_decode_session(*pskb, &fl, AF_INET) == 0)
	67	if (xfrm_lookup(&(pskb)->dst, &fl, (pskb)->sk, 0))
	68	return -1;
	69	#endif
	70
020b4c12 HW	71	/* Change in oif may mean change in hh_len. */
	72	hh_len = (*pskb)->dst->dev->hard_header_len;
	73	if (skb_headroom(*pskb) < hh_len) {
	74	struct sk_buff *nskb;
	75
	76	nskb = skb_realloc_headroom(*pskb, hh_len);
	77	if (!nskb)
	78	return -1;
	79	if ((*pskb)->sk)
	80	skb_set_owner_w(nskb, (*pskb)->sk);
	81	kfree_skb(*pskb);
	82	*pskb = nskb;
	83	}
	84
	85	return 0;
	86	}
	87	EXPORT_SYMBOL(ip_route_me_harder);
2cc7d573 HW	88
	89	/*
	90	* Extra routing may needed on local out, as the QUEUE target never
	91	* returns control to the table.
	92	*/
	93
	94	struct ip_rt_info {
	95	u_int32_t daddr;
	96	u_int32_t saddr;
	97	u_int8_t tos;
	98	};
	99
	100	static void queue_save(const struct sk_buff skb, struct nf_info info)
	101	{
	102	struct ip_rt_info *rt_info = nf_info_reroute(info);
	103
	104	if (info->hook == NF_IP_LOCAL_OUT) {
	105	const struct iphdr *iph = skb->nh.iph;
	106
	107	rt_info->tos = iph->tos;
	108	rt_info->daddr = iph->daddr;
	109	rt_info->saddr = iph->saddr;
	110	}
	111	}
	112
	113	static int queue_reroute(struct sk_buff *pskb, const struct nf_info info)
	114	{
	115	const struct ip_rt_info *rt_info = nf_info_reroute(info);
	116
	117	if (info->hook == NF_IP_LOCAL_OUT) {
	118	struct iphdr iph = (pskb)->nh.iph;
	119
	120	if (!(iph->tos == rt_info->tos
	121	&& iph->daddr == rt_info->daddr
	122	&& iph->saddr == rt_info->saddr))
	123	return ip_route_me_harder(pskb);
	124	}
	125	return 0;
	126	}
	127
	128	static struct nf_queue_rerouter ip_reroute = {
	129	.rer_size = sizeof(struct ip_rt_info),
	130	.save = queue_save,
	131	.reroute = queue_reroute,
	132	};
	133
	134	static int init(void)
	135	{
	136	return nf_register_queue_rerouter(PF_INET, &ip_reroute);
	137	}
	138
	139	static void fini(void)
	140	{
	141	nf_unregister_queue_rerouter(PF_INET);
	142	}
	143
	144	module_init(init);
	145	module_exit(fini);
	146
020b4c12	147	#endif /* CONFIG_NETFILTER */