[mirror_ubuntu-bionic-kernel.git] / net / ipv4 / xfrm4_input.c

/*
 * xfrm4_input.c
 *
 * Changes:
 *	YOSHIFUJI Hideaki @USAGI
 *		Split up af-specific portion
 *	Derek Atkins <derek@ihtfp.com>
 *		Add Encapsulation support
 * 	
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <net/inet_ecn.h>
#include <net/ip.h>
#include <net/xfrm.h>

int xfrm4_rcv(struct sk_buff *skb)
{
	return xfrm4_rcv_encap(skb, 0);
}

EXPORT_SYMBOL(xfrm4_rcv);

static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
{
	struct iphdr *outer_iph = skb->nh.iph;
	struct iphdr *inner_iph = skb->h.ipiph;

	if (INET_ECN_is_ce(outer_iph->tos))
		IP_ECN_set_ce(inner_iph);
}

static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, u32 *spi, u32 *seq)
{
	switch (nexthdr) {
	case IPPROTO_IPIP:
		if (!pskb_may_pull(skb, sizeof(struct iphdr)))
			return -EINVAL;
		*spi = skb->nh.iph->saddr;
		*seq = 0;
		return 0;
	}

	return xfrm_parse_spi(skb, nexthdr, spi, seq);
}

#ifdef CONFIG_NETFILTER
static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
{
	struct iphdr *iph = skb->nh.iph;

	if (skb->dst == NULL) {
		if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
		                   skb->dev))
			goto drop;
	}
	return dst_input(skb);
drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}
#endif

int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
{
	int err;
	u32 spi, seq;
	struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
	struct xfrm_state *x;
	int xfrm_nr = 0;
	int decaps = 0;

	if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
		goto drop;

	do {
		struct iphdr *iph = skb->nh.iph;

		if (xfrm_nr == XFRM_MAX_DEPTH)
			goto drop;

		x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET);
		if (x == NULL)
			goto drop;

		spin_lock(&x->lock);
		if (unlikely(x->km.state != XFRM_STATE_VALID))
			goto drop_unlock;

		if (x->props.replay_window && xfrm_replay_check(x, seq))
			goto drop_unlock;

		if (xfrm_state_check_expire(x))
			goto drop_unlock;

		xfrm_vec[xfrm_nr].decap.decap_type = encap_type;
		if (x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb))
			goto drop_unlock;

		/* only the first xfrm gets the encap type */
		encap_type = 0;

		if (x->props.replay_window)
			xfrm_replay_advance(x, seq);

		x->curlft.bytes += skb->len;
		x->curlft.packets++;

		spin_unlock(&x->lock);

		xfrm_vec[xfrm_nr++].xvec = x;

		iph = skb->nh.iph;

		if (x->props.mode) {
			if (iph->protocol != IPPROTO_IPIP)
				goto drop;
			if (!pskb_may_pull(skb, sizeof(struct iphdr)))
				goto drop;
			if (skb_cloned(skb) &&
			    pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
				goto drop;
			if (x->props.flags & XFRM_STATE_DECAP_DSCP)
				ipv4_copy_dscp(iph, skb->h.ipiph);
			if (!(x->props.flags & XFRM_STATE_NOECN))
				ipip_ecn_decapsulate(skb);
			skb->mac.raw = memmove(skb->data - skb->mac_len,
					       skb->mac.raw, skb->mac_len);
			skb->nh.raw = skb->data;
			memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
			decaps = 1;
			break;
		}

		if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 0)
			goto drop;
	} while (!err);

	/* Allocate new secpath or COW existing one. */

	if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
		struct sec_path *sp;
		sp = secpath_dup(skb->sp);
		if (!sp)
			goto drop;
		if (skb->sp)
			secpath_put(skb->sp);
		skb->sp = sp;
	}
	if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
		goto drop;

	memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
	skb->sp->len += xfrm_nr;

	nf_reset(skb);

	if (decaps) {
		if (!(skb->dev->flags&IFF_LOOPBACK)) {
			dst_release(skb->dst);
			skb->dst = NULL;
		}
		netif_rx(skb);
		return 0;
	} else {
#ifdef CONFIG_NETFILTER
		__skb_push(skb, skb->data - skb->nh.raw);
		skb->nh.iph->tot_len = htons(skb->len);
		ip_send_check(skb->nh.iph);

		NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
		        xfrm4_rcv_encap_finish);
		return 0;
#else
		return -skb->nh.iph->protocol;
#endif
	}

drop_unlock:
	spin_unlock(&x->lock);
	xfrm_state_put(x);
drop:
	while (--xfrm_nr >= 0)
		xfrm_state_put(xfrm_vec[xfrm_nr].xvec);

	kfree_skb(skb);
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* xfrm4_input.c
	3	*
	4	* Changes:
	5	* YOSHIFUJI Hideaki @USAGI
	6	* Split up af-specific portion
	7	* Derek Atkins <derek@ihtfp.com>
	8	* Add Encapsulation support
	9	*
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/string.h>
b05e1066 PM	14	#include <linux/netfilter.h>
b05e1066 PM	15	#include <linux/netfilter_ipv4.h>
1da177e4 LT	16	#include <net/inet_ecn.h>
	17	#include <net/ip.h>
	18	#include <net/xfrm.h>
	19
	20	int xfrm4_rcv(struct sk_buff *skb)
	21	{
	22	return xfrm4_rcv_encap(skb, 0);
	23	}
	24
	25	EXPORT_SYMBOL(xfrm4_rcv);
	26
	27	static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
	28	{
	29	struct iphdr *outer_iph = skb->nh.iph;
	30	struct iphdr *inner_iph = skb->h.ipiph;
	31
	32	if (INET_ECN_is_ce(outer_iph->tos))
	33	IP_ECN_set_ce(inner_iph);
	34	}
	35
	36	static int xfrm4_parse_spi(struct sk_buff skb, u8 nexthdr, u32 spi, u32 *seq)
	37	{
	38	switch (nexthdr) {
	39	case IPPROTO_IPIP:
	40	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	41	return -EINVAL;
	42	*spi = skb->nh.iph->saddr;
	43	*seq = 0;
	44	return 0;
	45	}
	46
	47	return xfrm_parse_spi(skb, nexthdr, spi, seq);
	48	}
	49
b05e1066 PM	50	#ifdef CONFIG_NETFILTER
	51	static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
	52	{
	53	struct iphdr *iph = skb->nh.iph;
	54
	55	if (skb->dst == NULL) {
	56	if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
	57	skb->dev))
	58	goto drop;
	59	}
	60	return dst_input(skb);
	61	drop:
	62	kfree_skb(skb);
	63	return NET_RX_DROP;
	64	}
	65	#endif
	66
1da177e4 LT	67	int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
	68	{
	69	int err;
	70	u32 spi, seq;
	71	struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
	72	struct xfrm_state *x;
	73	int xfrm_nr = 0;
	74	int decaps = 0;
	75
	76	if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
	77	goto drop;
	78
	79	do {
	80	struct iphdr *iph = skb->nh.iph;
	81
	82	if (xfrm_nr == XFRM_MAX_DEPTH)
	83	goto drop;
	84
	85	x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET);
	86	if (x == NULL)
	87	goto drop;
	88
	89	spin_lock(&x->lock);
	90	if (unlikely(x->km.state != XFRM_STATE_VALID))
	91	goto drop_unlock;
	92
	93	if (x->props.replay_window && xfrm_replay_check(x, seq))
	94	goto drop_unlock;
	95
	96	if (xfrm_state_check_expire(x))
	97	goto drop_unlock;
	98
	99	xfrm_vec[xfrm_nr].decap.decap_type = encap_type;
	100	if (x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb))
	101	goto drop_unlock;
	102
	103	/* only the first xfrm gets the encap type */
	104	encap_type = 0;
	105
	106	if (x->props.replay_window)
	107	xfrm_replay_advance(x, seq);
	108
	109	x->curlft.bytes += skb->len;
	110	x->curlft.packets++;
	111
	112	spin_unlock(&x->lock);
	113
	114	xfrm_vec[xfrm_nr++].xvec = x;
	115
	116	iph = skb->nh.iph;
	117
	118	if (x->props.mode) {
	119	if (iph->protocol != IPPROTO_IPIP)
	120	goto drop;
	121	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
	122	goto drop;
	123	if (skb_cloned(skb) &&
	124	pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
	125	goto drop;
	126	if (x->props.flags & XFRM_STATE_DECAP_DSCP)
	127	ipv4_copy_dscp(iph, skb->h.ipiph);
	128	if (!(x->props.flags & XFRM_STATE_NOECN))
	129	ipip_ecn_decapsulate(skb);
	130	skb->mac.raw = memmove(skb->data - skb->mac_len,
131	skb->mac.raw, skb->mac_len);
132	skb->nh.raw = skb->data;
133	memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
134	decaps = 1;
135	break;
136	}
137
138	if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 0)
139	goto drop;
140	} while (!err);
141
142	/* Allocate new secpath or COW existing one. */
143
144	if (!skb->sp \|\| atomic_read(&skb->sp->refcnt) != 1) {
145	struct sec_path *sp;
146	sp = secpath_dup(skb->sp);
147	if (!sp)
148	goto drop;
149	if (skb->sp)
150	secpath_put(skb->sp);
151	skb->sp = sp;
152	}
153	if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
154	goto drop;
155
156	memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
157	skb->sp->len += xfrm_nr;
158
b05e1066 PM	159	nf_reset(skb);
b05e1066 PM	160
1da177e4 LT	161	if (decaps) {
	162	if (!(skb->dev->flags&IFF_LOOPBACK)) {
	163	dst_release(skb->dst);
	164	skb->dst = NULL;
	165	}
	166	netif_rx(skb);
	167	return 0;
	168	} else {
b05e1066 PM	169	#ifdef CONFIG_NETFILTER
	170	__skb_push(skb, skb->data - skb->nh.raw);
	171	skb->nh.iph->tot_len = htons(skb->len);
	172	ip_send_check(skb->nh.iph);
	173
	174	NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
	175	xfrm4_rcv_encap_finish);
	176	return 0;
	177	#else
1da177e4	178	return -skb->nh.iph->protocol;
b05e1066	179	#endif
1da177e4 LT	180	}
	181
	182	drop_unlock:
	183	spin_unlock(&x->lock);
	184	xfrm_state_put(x);
	185	drop:
	186	while (--xfrm_nr >= 0)
	187	xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
	188
	189	kfree_skb(skb);
	190	return 0;
	191	}