[deliverable/linux.git] / net / ipv6 / mip6.c

/*
 * Copyright (C)2003-2006 Helsinki University of Technology
 * Copyright (C)2003-2006 USAGI/WIDE Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
/*
 * Authors:
 *	Noriaki TAKAMIYA @USAGI
 *	Masahide NAKAMURA @USAGI
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/time.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/rawv6.h>
#include <net/xfrm.h>
#include <net/mip6.h>

static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
{
	return (n - len + 16) & 0x7;
}

static inline void *mip6_padn(__u8 *data, __u8 padlen)
{
	if (!data)
		return NULL;
	if (padlen == 1) {
		data[0] = IPV6_TLV_PAD1;
	} else if (padlen > 1) {
		data[0] = IPV6_TLV_PADN;
		data[1] = padlen - 2;
		if (padlen > 2)
			memset(data+2, 0, data[1]);
	}
	return data + padlen;
}

static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
{
	icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
}

static int mip6_mh_len(int type)
{
	int len = 0;

	switch (type) {
	case IP6_MH_TYPE_BRR:
		len = 0;
		break;
	case IP6_MH_TYPE_HOTI:
	case IP6_MH_TYPE_COTI:
	case IP6_MH_TYPE_BU:
	case IP6_MH_TYPE_BACK:
		len = 1;
		break;
	case IP6_MH_TYPE_HOT:
	case IP6_MH_TYPE_COT:
	case IP6_MH_TYPE_BERROR:
		len = 2;
		break;
	}
	return len;
}

static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb)
{
	struct ip6_mh _hdr;
	const struct ip6_mh *mh;

	mh = skb_header_pointer(skb, skb_transport_offset(skb),
				sizeof(_hdr), &_hdr);
	if (!mh)
		return -1;

	if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len)
		return -1;

	if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
		LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
			       mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
		mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) +
				skb_network_header_len(skb));
		return -1;
	}

	if (mh->ip6mh_proto != IPPROTO_NONE) {
		LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
			       mh->ip6mh_proto);
		mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) +
				skb_network_header_len(skb));
		return -1;
	}

	return 0;
}

struct mip6_report_rate_limiter {
	spinlock_t lock;
	struct timeval stamp;
	int iif;
	struct in6_addr src;
	struct in6_addr dst;
};

static struct mip6_report_rate_limiter mip6_report_rl = {
	.lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
};

static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
{
	const struct ipv6hdr *iph = ipv6_hdr(skb);
	struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
	int err = destopt->nexthdr;

	spin_lock(&x->lock);
	if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
	    !ipv6_addr_any((struct in6_addr *)x->coaddr))
		err = -ENOENT;
	spin_unlock(&x->lock);

	return err;
}

/* Destination Option Header is inserted.
 * IP Header's src address is replaced with Home Address Option in
 * Destination Option Header.
 */
static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ipv6hdr *iph;
	struct ipv6_destopt_hdr *dstopt;
	struct ipv6_destopt_hao *hao;
	u8 nexthdr;
	int len;

	skb_push(skb, -skb_network_offset(skb));
	iph = ipv6_hdr(skb);

	nexthdr = *skb_mac_header(skb);
	*skb_mac_header(skb) = IPPROTO_DSTOPTS;

	dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
	dstopt->nexthdr = nexthdr;

	hao = mip6_padn((char *)(dstopt + 1),
			calc_padlen(sizeof(*dstopt), 6));

	hao->type = IPV6_TLV_HAO;
	BUILD_BUG_ON(sizeof(*hao) != 18);
	hao->length = sizeof(*hao) - 2;

	len = ((char *)hao - (char *)dstopt) + sizeof(*hao);

	memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
	spin_lock_bh(&x->lock);
	memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
	spin_unlock_bh(&x->lock);

	WARN_ON(len != x->props.header_len);
	dstopt->hdrlen = (x->props.header_len >> 3) - 1;

	return 0;
}

static inline int mip6_report_rl_allow(struct timeval *stamp,
				       const struct in6_addr *dst,
				       const struct in6_addr *src, int iif)
{
	int allow = 0;

	spin_lock_bh(&mip6_report_rl.lock);
	if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec ||
	    mip6_report_rl.stamp.tv_usec != stamp->tv_usec ||
	    mip6_report_rl.iif != iif ||
	    !ipv6_addr_equal(&mip6_report_rl.src, src) ||
	    !ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
		mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
		mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
		mip6_report_rl.iif = iif;
		mip6_report_rl.src = *src;
		mip6_report_rl.dst = *dst;
		allow = 1;
	}
	spin_unlock_bh(&mip6_report_rl.lock);
	return allow;
}

static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb,
			       const struct flowi *fl)
{
	struct net *net = xs_net(x);
	struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb;
	const struct flowi6 *fl6 = &fl->u.ip6;
	struct ipv6_destopt_hao *hao = NULL;
	struct xfrm_selector sel;
	int offset;
	struct timeval stamp;
	int err = 0;

	if (unlikely(fl6->flowi6_proto == IPPROTO_MH &&
		     fl6->fl6_mh_type <= IP6_MH_TYPE_MAX))
		goto out;

	if (likely(opt->dsthao)) {
		offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
		if (likely(offset >= 0))
			hao = (struct ipv6_destopt_hao *)
					(skb_network_header(skb) + offset);
	}

	skb_get_timestamp(skb, &stamp);

	if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
				  hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
				  opt->iif))
		goto out;

	memset(&sel, 0, sizeof(sel));
	memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
	       sizeof(sel.daddr));
	sel.prefixlen_d = 128;
	memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
	       sizeof(sel.saddr));
	sel.prefixlen_s = 128;
	sel.family = AF_INET6;
	sel.proto = fl6->flowi6_proto;
	sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
	if (sel.dport)
		sel.dport_mask = htons(~0);
	sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
	if (sel.sport)
		sel.sport_mask = htons(~0);
	sel.ifindex = fl6->flowi6_oif;

	err = km_report(net, IPPROTO_DSTOPTS, &sel,
			(hao ? (xfrm_address_t *)&hao->addr : NULL));

 out:
	return err;
}

static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
			       u8 **nexthdr)
{
	u16 offset = sizeof(struct ipv6hdr);
	struct ipv6_opt_hdr *exthdr =
				   (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
	const unsigned char *nh = skb_network_header(skb);
	unsigned int packet_len = skb->tail - skb->network_header;
	int found_rhdr = 0;

	*nexthdr = &ipv6_hdr(skb)->nexthdr;

	while (offset + 1 <= packet_len) {

		switch (**nexthdr) {
		case NEXTHDR_HOP:
			break;
		case NEXTHDR_ROUTING:
			found_rhdr = 1;
			break;
		case NEXTHDR_DEST:
			/*
			 * HAO MUST NOT appear more than once.
			 * XXX: It is better to try to find by the end of
			 * XXX: packet if HAO exists.
			 */
			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
				LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
				return offset;
			}

			if (found_rhdr)
				return offset;

			break;
		default:
			return offset;
		}

		offset += ipv6_optlen(exthdr);
		*nexthdr = &exthdr->nexthdr;
		exthdr = (struct ipv6_opt_hdr *)(nh + offset);
	}

	return offset;
}

static int mip6_destopt_init_state(struct xfrm_state *x)
{
	if (x->id.spi) {
		pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
		return -EINVAL;
	}
	if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
		pr_info("%s: state's mode is not %u: %u\n",
			__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
		return -EINVAL;
	}

	x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
		calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
		sizeof(struct ipv6_destopt_hao);
	WARN_ON(x->props.header_len != 24);

	return 0;
}

/*
 * Do nothing about destroying since it has no specific operation for
 * destination options header unlike IPsec protocols.
 */
static void mip6_destopt_destroy(struct xfrm_state *x)
{
}

static const struct xfrm_type mip6_destopt_type =
{
	.description	= "MIP6DESTOPT",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_DSTOPTS,
	.flags		= XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR,
	.init_state	= mip6_destopt_init_state,
	.destructor	= mip6_destopt_destroy,
	.input		= mip6_destopt_input,
	.output		= mip6_destopt_output,
	.reject		= mip6_destopt_reject,
	.hdr_offset	= mip6_destopt_offset,
};

static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
{
	const struct ipv6hdr *iph = ipv6_hdr(skb);
	struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
	int err = rt2->rt_hdr.nexthdr;

	spin_lock(&x->lock);
	if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
	    !ipv6_addr_any((struct in6_addr *)x->coaddr))
		err = -ENOENT;
	spin_unlock(&x->lock);

	return err;
}

/* Routing Header type 2 is inserted.
 * IP Header's dst address is replaced with Routing Header's Home Address.
 */
static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ipv6hdr *iph;
	struct rt2_hdr *rt2;
	u8 nexthdr;

	skb_push(skb, -skb_network_offset(skb));
	iph = ipv6_hdr(skb);

	nexthdr = *skb_mac_header(skb);
	*skb_mac_header(skb) = IPPROTO_ROUTING;

	rt2 = (struct rt2_hdr *)skb_transport_header(skb);
	rt2->rt_hdr.nexthdr = nexthdr;
	rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
	rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
	rt2->rt_hdr.segments_left = 1;
	memset(&rt2->reserved, 0, sizeof(rt2->reserved));

	WARN_ON(rt2->rt_hdr.hdrlen != 2);

	memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
	spin_lock_bh(&x->lock);
	memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
	spin_unlock_bh(&x->lock);

	return 0;
}

static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb,
			     u8 **nexthdr)
{
	u16 offset = sizeof(struct ipv6hdr);
	struct ipv6_opt_hdr *exthdr =
				   (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
	const unsigned char *nh = skb_network_header(skb);
	unsigned int packet_len = skb->tail - skb->network_header;
	int found_rhdr = 0;

	*nexthdr = &ipv6_hdr(skb)->nexthdr;

	while (offset + 1 <= packet_len) {

		switch (**nexthdr) {
		case NEXTHDR_HOP:
			break;
		case NEXTHDR_ROUTING:
			if (offset + 3 <= packet_len) {
				struct ipv6_rt_hdr *rt;
				rt = (struct ipv6_rt_hdr *)(nh + offset);
				if (rt->type != 0)
					return offset;
			}
			found_rhdr = 1;
			break;
		case NEXTHDR_DEST:
			if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
				return offset;

			if (found_rhdr)
				return offset;

			break;
		default:
			return offset;
		}

		offset += ipv6_optlen(exthdr);
		*nexthdr = &exthdr->nexthdr;
		exthdr = (struct ipv6_opt_hdr *)(nh + offset);
	}

	return offset;
}

static int mip6_rthdr_init_state(struct xfrm_state *x)
{
	if (x->id.spi) {
		pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
		return -EINVAL;
	}
	if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
		pr_info("%s: state's mode is not %u: %u\n",
			__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
		return -EINVAL;
	}

	x->props.header_len = sizeof(struct rt2_hdr);

	return 0;
}

/*
 * Do nothing about destroying since it has no specific operation for routing
 * header type 2 unlike IPsec protocols.
 */
static void mip6_rthdr_destroy(struct xfrm_state *x)
{
}

static const struct xfrm_type mip6_rthdr_type =
{
	.description	= "MIP6RT",
	.owner		= THIS_MODULE,
	.proto	     	= IPPROTO_ROUTING,
	.flags		= XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR,
	.init_state	= mip6_rthdr_init_state,
	.destructor	= mip6_rthdr_destroy,
	.input		= mip6_rthdr_input,
	.output		= mip6_rthdr_output,
	.hdr_offset	= mip6_rthdr_offset,
};

static int __init mip6_init(void)
{
	pr_info("Mobile IPv6\n");

	if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
		pr_info("%s: can't add xfrm type(destopt)\n", __func__);
		goto mip6_destopt_xfrm_fail;
	}
	if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
		pr_info("%s: can't add xfrm type(rthdr)\n", __func__);
		goto mip6_rthdr_xfrm_fail;
	}
	if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
		pr_info("%s: can't add rawv6 mh filter\n", __func__);
		goto mip6_rawv6_mh_fail;
	}


	return 0;

 mip6_rawv6_mh_fail:
	xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
 mip6_rthdr_xfrm_fail:
	xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
 mip6_destopt_xfrm_fail:
	return -EAGAIN;
}

static void __exit mip6_fini(void)
{
	if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
		pr_info("%s: can't remove rawv6 mh filter\n", __func__);
	if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
		pr_info("%s: can't remove xfrm type(rthdr)\n", __func__);
	if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
		pr_info("%s: can't remove xfrm type(destopt)\n", __func__);
}

module_init(mip6_init);
module_exit(mip6_fini);

MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);
Commit	Line	Data
	1	/*
	2	* Copyright (C)2003-2006 Helsinki University of Technology
	3	* Copyright (C)2003-2006 USAGI/WIDE Project
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License as published by
	7	* the Free Software Foundation; either version 2 of the License, or
	8	* (at your option) any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*/
	19	/*
	20	* Authors:
	21	* Noriaki TAKAMIYA @USAGI
	22	* Masahide NAKAMURA @USAGI
	23	*/
	24
	25	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	26
	27	#include <linux/module.h>
	28	#include <linux/skbuff.h>
	29	#include <linux/time.h>
	30	#include <linux/ipv6.h>
	31	#include <linux/icmpv6.h>
	32	#include <net/sock.h>
	33	#include <net/ipv6.h>
	34	#include <net/ip6_checksum.h>
	35	#include <net/rawv6.h>
	36	#include <net/xfrm.h>
	37	#include <net/mip6.h>
	38
	39	static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
	40	{
	41	return (n - len + 16) & 0x7;
	42	}
	43
	44	static inline void mip6_padn(__u8 data, __u8 padlen)
	45	{
	46	if (!data)
	47	return NULL;
	48	if (padlen == 1) {
	49	data[0] = IPV6_TLV_PAD1;
	50	} else if (padlen > 1) {
	51	data[0] = IPV6_TLV_PADN;
	52	data[1] = padlen - 2;
	53	if (padlen > 2)
	54	memset(data+2, 0, data[1]);
	55	}
	56	return data + padlen;
	57	}
	58
	59	static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos)
	60	{
	61	icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos);
	62	}
	63
	64	static int mip6_mh_len(int type)
	65	{
	66	int len = 0;
	67
	68	switch (type) {
	69	case IP6_MH_TYPE_BRR:
	70	len = 0;
	71	break;
	72	case IP6_MH_TYPE_HOTI:
	73	case IP6_MH_TYPE_COTI:
	74	case IP6_MH_TYPE_BU:
	75	case IP6_MH_TYPE_BACK:
	76	len = 1;
	77	break;
	78	case IP6_MH_TYPE_HOT:
	79	case IP6_MH_TYPE_COT:
	80	case IP6_MH_TYPE_BERROR:
	81	len = 2;
	82	break;
	83	}
	84	return len;
	85	}
	86
	87	static int mip6_mh_filter(struct sock sk, struct sk_buff skb)
	88	{
	89	struct ip6_mh _hdr;
	90	const struct ip6_mh *mh;
	91
	92	mh = skb_header_pointer(skb, skb_transport_offset(skb),
	93	sizeof(_hdr), &_hdr);
	94	if (!mh)
	95	return -1;
	96
	97	if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len)
	98	return -1;
	99
	100	if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) {
	101	LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n",
	102	mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type));
	103	mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) +
	104	skb_network_header_len(skb));
	105	return -1;
	106	}
	107
	108	if (mh->ip6mh_proto != IPPROTO_NONE) {
	109	LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n",
	110	mh->ip6mh_proto);
	111	mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) +
	112	skb_network_header_len(skb));
	113	return -1;
	114	}
	115
	116	return 0;
	117	}
	118
	119	struct mip6_report_rate_limiter {
	120	spinlock_t lock;
	121	struct timeval stamp;
	122	int iif;
	123	struct in6_addr src;
	124	struct in6_addr dst;
	125	};
	126
	127	static struct mip6_report_rate_limiter mip6_report_rl = {
	128	.lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock)
	129	};
	130
	131	static int mip6_destopt_input(struct xfrm_state x, struct sk_buff skb)
	132	{
	133	const struct ipv6hdr *iph = ipv6_hdr(skb);
	134	struct ipv6_destopt_hdr destopt = (struct ipv6_destopt_hdr )skb->data;
	135	int err = destopt->nexthdr;
	136
	137	spin_lock(&x->lock);
	138	if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
	139	!ipv6_addr_any((struct in6_addr *)x->coaddr))
	140	err = -ENOENT;
	141	spin_unlock(&x->lock);
	142
	143	return err;
	144	}
	145
	146	/* Destination Option Header is inserted.
	147	* IP Header's src address is replaced with Home Address Option in
	148	* Destination Option Header.
	149	*/
	150	static int mip6_destopt_output(struct xfrm_state x, struct sk_buff skb)
	151	{
	152	struct ipv6hdr *iph;
	153	struct ipv6_destopt_hdr *dstopt;
	154	struct ipv6_destopt_hao *hao;
	155	u8 nexthdr;
	156	int len;
	157
	158	skb_push(skb, -skb_network_offset(skb));
	159	iph = ipv6_hdr(skb);
	160
	161	nexthdr = *skb_mac_header(skb);
	162	*skb_mac_header(skb) = IPPROTO_DSTOPTS;
	163
	164	dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb);
	165	dstopt->nexthdr = nexthdr;
	166
	167	hao = mip6_padn((char *)(dstopt + 1),
	168	calc_padlen(sizeof(*dstopt), 6));
	169
	170	hao->type = IPV6_TLV_HAO;
	171	BUILD_BUG_ON(sizeof(*hao) != 18);
	172	hao->length = sizeof(*hao) - 2;
	173
	174	len = ((char )hao - (char )dstopt) + sizeof(*hao);
	175
	176	memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
	177	spin_lock_bh(&x->lock);
	178	memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
	179	spin_unlock_bh(&x->lock);
	180
	181	WARN_ON(len != x->props.header_len);
	182	dstopt->hdrlen = (x->props.header_len >> 3) - 1;
	183
	184	return 0;
	185	}
	186
	187	static inline int mip6_report_rl_allow(struct timeval *stamp,
	188	const struct in6_addr *dst,
	189	const struct in6_addr *src, int iif)
	190	{
	191	int allow = 0;
	192
	193	spin_lock_bh(&mip6_report_rl.lock);
	194	if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec \|\|
	195	mip6_report_rl.stamp.tv_usec != stamp->tv_usec \|\|
	196	mip6_report_rl.iif != iif \|\|
	197	!ipv6_addr_equal(&mip6_report_rl.src, src) \|\|
	198	!ipv6_addr_equal(&mip6_report_rl.dst, dst)) {
	199	mip6_report_rl.stamp.tv_sec = stamp->tv_sec;
	200	mip6_report_rl.stamp.tv_usec = stamp->tv_usec;
	201	mip6_report_rl.iif = iif;
	202	mip6_report_rl.src = *src;
	203	mip6_report_rl.dst = *dst;
	204	allow = 1;
	205	}
	206	spin_unlock_bh(&mip6_report_rl.lock);
	207	return allow;
	208	}
	209
	210	static int mip6_destopt_reject(struct xfrm_state x, struct sk_buff skb,
	211	const struct flowi *fl)
	212	{
	213	struct net *net = xs_net(x);
	214	struct inet6_skb_parm opt = (struct inet6_skb_parm )skb->cb;
	215	const struct flowi6 *fl6 = &fl->u.ip6;
	216	struct ipv6_destopt_hao *hao = NULL;
	217	struct xfrm_selector sel;
	218	int offset;
	219	struct timeval stamp;
	220	int err = 0;
	221
	222	if (unlikely(fl6->flowi6_proto == IPPROTO_MH &&
	223	fl6->fl6_mh_type <= IP6_MH_TYPE_MAX))
	224	goto out;
	225
	226	if (likely(opt->dsthao)) {
	227	offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO);
	228	if (likely(offset >= 0))
	229	hao = (struct ipv6_destopt_hao *)
	230	(skb_network_header(skb) + offset);
	231	}
	232
	233	skb_get_timestamp(skb, &stamp);
	234
	235	if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr,
	236	hao ? &hao->addr : &ipv6_hdr(skb)->saddr,
	237	opt->iif))
	238	goto out;
	239
	240	memset(&sel, 0, sizeof(sel));
	241	memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr,
	242	sizeof(sel.daddr));
	243	sel.prefixlen_d = 128;
	244	memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
	245	sizeof(sel.saddr));
	246	sel.prefixlen_s = 128;
	247	sel.family = AF_INET6;
	248	sel.proto = fl6->flowi6_proto;
	249	sel.dport = xfrm_flowi_dport(fl, &fl6->uli);
	250	if (sel.dport)
	251	sel.dport_mask = htons(~0);
	252	sel.sport = xfrm_flowi_sport(fl, &fl6->uli);
	253	if (sel.sport)
	254	sel.sport_mask = htons(~0);
	255	sel.ifindex = fl6->flowi6_oif;
	256
	257	err = km_report(net, IPPROTO_DSTOPTS, &sel,
	258	(hao ? (xfrm_address_t *)&hao->addr : NULL));
	259
	260	out:
	261	return err;
	262	}
	263
	264	static int mip6_destopt_offset(struct xfrm_state x, struct sk_buff skb,
	265	u8 **nexthdr)
	266	{
	267	u16 offset = sizeof(struct ipv6hdr);
	268	struct ipv6_opt_hdr *exthdr =
	269	(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
	270	const unsigned char *nh = skb_network_header(skb);
	271	unsigned int packet_len = skb->tail - skb->network_header;
	272	int found_rhdr = 0;
	273
	274	*nexthdr = &ipv6_hdr(skb)->nexthdr;
	275
	276	while (offset + 1 <= packet_len) {
	277
	278	switch (**nexthdr) {
	279	case NEXTHDR_HOP:
	280	break;
	281	case NEXTHDR_ROUTING:
	282	found_rhdr = 1;
	283	break;
	284	case NEXTHDR_DEST:
	285	/*
	286	* HAO MUST NOT appear more than once.
	287	* XXX: It is better to try to find by the end of
	288	* XXX: packet if HAO exists.
	289	*/
	290	if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
	291	LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
	292	return offset;
	293	}
	294
	295	if (found_rhdr)
	296	return offset;
	297
	298	break;
	299	default:
	300	return offset;
	301	}
	302
	303	offset += ipv6_optlen(exthdr);
	304	*nexthdr = &exthdr->nexthdr;
	305	exthdr = (struct ipv6_opt_hdr *)(nh + offset);
	306	}
	307
	308	return offset;
	309	}
	310
	311	static int mip6_destopt_init_state(struct xfrm_state *x)
	312	{
	313	if (x->id.spi) {
	314	pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
	315	return -EINVAL;
	316	}
	317	if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
	318	pr_info("%s: state's mode is not %u: %u\n",
	319	__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
	320	return -EINVAL;
	321	}
	322
	323	x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
	324	calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
	325	sizeof(struct ipv6_destopt_hao);
	326	WARN_ON(x->props.header_len != 24);
	327
	328	return 0;
	329	}
	330
	331	/*
	332	* Do nothing about destroying since it has no specific operation for
	333	* destination options header unlike IPsec protocols.
	334	*/
	335	static void mip6_destopt_destroy(struct xfrm_state *x)
	336	{
	337	}
	338
	339	static const struct xfrm_type mip6_destopt_type =
	340	{
	341	.description = "MIP6DESTOPT",
	342	.owner = THIS_MODULE,
	343	.proto = IPPROTO_DSTOPTS,
	344	.flags = XFRM_TYPE_NON_FRAGMENT \| XFRM_TYPE_LOCAL_COADDR,
	345	.init_state = mip6_destopt_init_state,
	346	.destructor = mip6_destopt_destroy,
	347	.input = mip6_destopt_input,
	348	.output = mip6_destopt_output,
	349	.reject = mip6_destopt_reject,
	350	.hdr_offset = mip6_destopt_offset,
	351	};
	352
	353	static int mip6_rthdr_input(struct xfrm_state x, struct sk_buff skb)
	354	{
	355	const struct ipv6hdr *iph = ipv6_hdr(skb);
	356	struct rt2_hdr rt2 = (struct rt2_hdr )skb->data;
	357	int err = rt2->rt_hdr.nexthdr;
	358
	359	spin_lock(&x->lock);
	360	if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) &&
	361	!ipv6_addr_any((struct in6_addr *)x->coaddr))
	362	err = -ENOENT;
	363	spin_unlock(&x->lock);
	364
	365	return err;
	366	}
	367
	368	/* Routing Header type 2 is inserted.
	369	* IP Header's dst address is replaced with Routing Header's Home Address.
	370	*/
	371	static int mip6_rthdr_output(struct xfrm_state x, struct sk_buff skb)
	372	{
	373	struct ipv6hdr *iph;
	374	struct rt2_hdr *rt2;
	375	u8 nexthdr;
	376
	377	skb_push(skb, -skb_network_offset(skb));
	378	iph = ipv6_hdr(skb);
	379
	380	nexthdr = *skb_mac_header(skb);
	381	*skb_mac_header(skb) = IPPROTO_ROUTING;
	382
	383	rt2 = (struct rt2_hdr *)skb_transport_header(skb);
	384	rt2->rt_hdr.nexthdr = nexthdr;
	385	rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1;
	386	rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2;
	387	rt2->rt_hdr.segments_left = 1;
	388	memset(&rt2->reserved, 0, sizeof(rt2->reserved));
	389
	390	WARN_ON(rt2->rt_hdr.hdrlen != 2);
	391
	392	memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr));
	393	spin_lock_bh(&x->lock);
	394	memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr));
	395	spin_unlock_bh(&x->lock);
	396
	397	return 0;
	398	}
	399
	400	static int mip6_rthdr_offset(struct xfrm_state x, struct sk_buff skb,
	401	u8 **nexthdr)
	402	{
	403	u16 offset = sizeof(struct ipv6hdr);
	404	struct ipv6_opt_hdr *exthdr =
	405	(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
	406	const unsigned char *nh = skb_network_header(skb);
	407	unsigned int packet_len = skb->tail - skb->network_header;
	408	int found_rhdr = 0;
	409
	410	*nexthdr = &ipv6_hdr(skb)->nexthdr;
	411
	412	while (offset + 1 <= packet_len) {
	413
	414	switch (**nexthdr) {
	415	case NEXTHDR_HOP:
	416	break;
	417	case NEXTHDR_ROUTING:
	418	if (offset + 3 <= packet_len) {
	419	struct ipv6_rt_hdr *rt;
	420	rt = (struct ipv6_rt_hdr *)(nh + offset);
	421	if (rt->type != 0)
	422	return offset;
	423	}
	424	found_rhdr = 1;
	425	break;
	426	case NEXTHDR_DEST:
	427	if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
	428	return offset;
	429
	430	if (found_rhdr)
	431	return offset;
	432
	433	break;
	434	default:
	435	return offset;
	436	}
	437
	438	offset += ipv6_optlen(exthdr);
	439	*nexthdr = &exthdr->nexthdr;
	440	exthdr = (struct ipv6_opt_hdr *)(nh + offset);
	441	}
	442
	443	return offset;
	444	}
	445
	446	static int mip6_rthdr_init_state(struct xfrm_state *x)
	447	{
	448	if (x->id.spi) {
	449	pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi);
	450	return -EINVAL;
	451	}
	452	if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
	453	pr_info("%s: state's mode is not %u: %u\n",
	454	__func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
	455	return -EINVAL;
	456	}
	457
	458	x->props.header_len = sizeof(struct rt2_hdr);
	459
	460	return 0;
	461	}
	462
	463	/*
	464	* Do nothing about destroying since it has no specific operation for routing
	465	* header type 2 unlike IPsec protocols.
	466	*/
	467	static void mip6_rthdr_destroy(struct xfrm_state *x)
	468	{
	469	}
	470
	471	static const struct xfrm_type mip6_rthdr_type =
	472	{
	473	.description = "MIP6RT",
	474	.owner = THIS_MODULE,
	475	.proto = IPPROTO_ROUTING,
	476	.flags = XFRM_TYPE_NON_FRAGMENT \| XFRM_TYPE_REMOTE_COADDR,
	477	.init_state = mip6_rthdr_init_state,
	478	.destructor = mip6_rthdr_destroy,
	479	.input = mip6_rthdr_input,
	480	.output = mip6_rthdr_output,
	481	.hdr_offset = mip6_rthdr_offset,
	482	};
	483
	484	static int __init mip6_init(void)
	485	{
	486	pr_info("Mobile IPv6\n");
	487
	488	if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
	489	pr_info("%s: can't add xfrm type(destopt)\n", __func__);
	490	goto mip6_destopt_xfrm_fail;
	491	}
	492	if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
	493	pr_info("%s: can't add xfrm type(rthdr)\n", __func__);
	494	goto mip6_rthdr_xfrm_fail;
	495	}
	496	if (rawv6_mh_filter_register(mip6_mh_filter) < 0) {
	497	pr_info("%s: can't add rawv6 mh filter\n", __func__);
	498	goto mip6_rawv6_mh_fail;
	499	}
	500
	501
	502	return 0;
	503
	504	mip6_rawv6_mh_fail:
	505	xfrm_unregister_type(&mip6_rthdr_type, AF_INET6);
	506	mip6_rthdr_xfrm_fail:
	507	xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
	508	mip6_destopt_xfrm_fail:
	509	return -EAGAIN;
	510	}
	511
	512	static void __exit mip6_fini(void)
	513	{
	514	if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0)
	515	pr_info("%s: can't remove rawv6 mh filter\n", __func__);
	516	if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
	517	pr_info("%s: can't remove xfrm type(rthdr)\n", __func__);
	518	if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
	519	pr_info("%s: can't remove xfrm type(destopt)\n", __func__);
	520	}
	521
	522	module_init(mip6_init);
	523	module_exit(mip6_fini);
	524
	525	MODULE_LICENSE("GPL");
	526	MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS);
	527	MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING);