[linux-2.6-block.git] / net / ipv6 / seg6_iptunnel.c

/*
 *  SR-IPv6 implementation
 *
 *  Author:
 *  David Lebrun <david.lebrun@uclouvain.be>
 *
 *
 *  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.
 */

#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/lwtunnel.h>
#include <net/netevent.h>
#include <net/netns/generic.h>
#include <net/ip6_fib.h>
#include <net/route.h>
#include <net/seg6.h>
#include <linux/seg6.h>
#include <linux/seg6_iptunnel.h>
#include <net/addrconf.h>
#include <net/ip6_route.h>
#ifdef CONFIG_DST_CACHE
#include <net/dst_cache.h>
#endif
#ifdef CONFIG_IPV6_SEG6_HMAC
#include <net/seg6_hmac.h>
#endif

struct seg6_lwt {
#ifdef CONFIG_DST_CACHE
	struct dst_cache cache;
#endif
	struct seg6_iptunnel_encap tuninfo[0];
};

static inline struct seg6_lwt *seg6_lwt_lwtunnel(struct lwtunnel_state *lwt)
{
	return (struct seg6_lwt *)lwt->data;
}

static inline struct seg6_iptunnel_encap *
seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
{
	return seg6_lwt_lwtunnel(lwt)->tuninfo;
}

static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
	[SEG6_IPTUNNEL_SRH]	= { .type = NLA_BINARY },
};

int nla_put_srh(struct sk_buff *skb, int attrtype,
		struct seg6_iptunnel_encap *tuninfo)
{
	struct seg6_iptunnel_encap *data;
	struct nlattr *nla;
	int len;

	len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);

	nla = nla_reserve(skb, attrtype, len);
	if (!nla)
		return -EMSGSIZE;

	data = nla_data(nla);
	memcpy(data, tuninfo, len);

	return 0;
}

static void set_tun_src(struct net *net, struct net_device *dev,
			struct in6_addr *daddr, struct in6_addr *saddr)
{
	struct seg6_pernet_data *sdata = seg6_pernet(net);
	struct in6_addr *tun_src;

	rcu_read_lock();

	tun_src = rcu_dereference(sdata->tun_src);

	if (!ipv6_addr_any(tun_src)) {
		memcpy(saddr, tun_src, sizeof(struct in6_addr));
	} else {
		ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
				   saddr);
	}

	rcu_read_unlock();
}

/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
static int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
{
	struct net *net = dev_net(skb_dst(skb)->dev);
	struct ipv6hdr *hdr, *inner_hdr;
	struct ipv6_sr_hdr *isrh;
	int hdrlen, tot_len, err;

	hdrlen = (osrh->hdrlen + 1) << 3;
	tot_len = hdrlen + sizeof(*hdr);

	err = pskb_expand_head(skb, tot_len, 0, GFP_ATOMIC);
	if (unlikely(err))
		return err;

	inner_hdr = ipv6_hdr(skb);

	skb_push(skb, tot_len);
	skb_reset_network_header(skb);
	skb_mac_header_rebuild(skb);
	hdr = ipv6_hdr(skb);

	/* inherit tc, flowlabel and hlim
	 * hlim will be decremented in ip6_forward() afterwards and
	 * decapsulation will overwrite inner hlim with outer hlim
	 */
	ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
		     ip6_flowlabel(inner_hdr));
	hdr->hop_limit = inner_hdr->hop_limit;
	hdr->nexthdr = NEXTHDR_ROUTING;

	isrh = (void *)hdr + sizeof(*hdr);
	memcpy(isrh, osrh, hdrlen);

	isrh->nexthdr = NEXTHDR_IPV6;

	hdr->daddr = isrh->segments[isrh->first_segment];
	set_tun_src(net, skb->dev, &hdr->daddr, &hdr->saddr);

#ifdef CONFIG_IPV6_SEG6_HMAC
	if (sr_has_hmac(isrh)) {
		err = seg6_push_hmac(net, &hdr->saddr, isrh);
		if (unlikely(err))
			return err;
	}
#endif

	skb_postpush_rcsum(skb, hdr, tot_len);

	return 0;
}

/* insert an SRH within an IPv6 packet, just after the IPv6 header */
#ifdef CONFIG_IPV6_SEG6_INLINE
static int seg6_do_srh_inline(struct sk_buff *skb, struct ipv6_sr_hdr *osrh)
{
	struct ipv6hdr *hdr, *oldhdr;
	struct ipv6_sr_hdr *isrh;
	int hdrlen, err;

	hdrlen = (osrh->hdrlen + 1) << 3;

	err = pskb_expand_head(skb, hdrlen, 0, GFP_ATOMIC);
	if (unlikely(err))
		return err;

	oldhdr = ipv6_hdr(skb);

	skb_pull(skb, sizeof(struct ipv6hdr));
	skb_postpull_rcsum(skb, skb_network_header(skb),
			   sizeof(struct ipv6hdr));

	skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
	skb_reset_network_header(skb);
	skb_mac_header_rebuild(skb);

	hdr = ipv6_hdr(skb);

	memmove(hdr, oldhdr, sizeof(*hdr));

	isrh = (void *)hdr + sizeof(*hdr);
	memcpy(isrh, osrh, hdrlen);

	isrh->nexthdr = hdr->nexthdr;
	hdr->nexthdr = NEXTHDR_ROUTING;

	isrh->segments[0] = hdr->daddr;
	hdr->daddr = isrh->segments[isrh->first_segment];

#ifdef CONFIG_IPV6_SEG6_HMAC
	if (sr_has_hmac(isrh)) {
		struct net *net = dev_net(skb_dst(skb)->dev);

		err = seg6_push_hmac(net, &hdr->saddr, isrh);
		if (unlikely(err))
			return err;
	}
#endif

	skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);

	return 0;
}
#endif

static int seg6_do_srh(struct sk_buff *skb)
{
	struct dst_entry *dst = skb_dst(skb);
	struct seg6_iptunnel_encap *tinfo;
	int err = 0;

	tinfo = seg6_encap_lwtunnel(dst->lwtstate);

	if (likely(!skb->encapsulation)) {
		skb_reset_inner_headers(skb);
		skb->encapsulation = 1;
	}

	switch (tinfo->mode) {
#ifdef CONFIG_IPV6_SEG6_INLINE
	case SEG6_IPTUN_MODE_INLINE:
		err = seg6_do_srh_inline(skb, tinfo->srh);
		skb_reset_inner_headers(skb);
		break;
#endif
	case SEG6_IPTUN_MODE_ENCAP:
		err = seg6_do_srh_encap(skb, tinfo->srh);
		break;
	}

	if (err)
		return err;

	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	skb_set_transport_header(skb, sizeof(struct ipv6hdr));

	skb_set_inner_protocol(skb, skb->protocol);

	return 0;
}

int seg6_input(struct sk_buff *skb)
{
	int err;

	err = seg6_do_srh(skb);
	if (unlikely(err)) {
		kfree_skb(skb);
		return err;
	}

	skb_dst_drop(skb);
	ip6_route_input(skb);

	return dst_input(skb);
}

int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct dst_entry *orig_dst = skb_dst(skb);
	struct dst_entry *dst = NULL;
	struct seg6_lwt *slwt;
	int err = -EINVAL;

	err = seg6_do_srh(skb);
	if (unlikely(err))
		goto drop;

	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);

#ifdef CONFIG_DST_CACHE
	dst = dst_cache_get(&slwt->cache);
#endif

	if (unlikely(!dst)) {
		struct ipv6hdr *hdr = ipv6_hdr(skb);
		struct flowi6 fl6;

		fl6.daddr = hdr->daddr;
		fl6.saddr = hdr->saddr;
		fl6.flowlabel = ip6_flowinfo(hdr);
		fl6.flowi6_mark = skb->mark;
		fl6.flowi6_proto = hdr->nexthdr;

		dst = ip6_route_output(net, NULL, &fl6);
		if (dst->error) {
			err = dst->error;
			dst_release(dst);
			goto drop;
		}

#ifdef CONFIG_DST_CACHE
		dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
#endif
	}

	skb_dst_drop(skb);
	skb_dst_set(skb, dst);

	return dst_output(net, sk, skb);
drop:
	kfree_skb(skb);
	return err;
}

static int seg6_build_state(struct net_device *dev, struct nlattr *nla,
			    unsigned int family, const void *cfg,
			    struct lwtunnel_state **ts)
{
	struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
	struct seg6_iptunnel_encap *tuninfo;
	struct lwtunnel_state *newts;
	int tuninfo_len, min_size;
	struct seg6_lwt *slwt;
	int err;

	err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
			       seg6_iptunnel_policy);

	if (err < 0)
		return err;

	if (!tb[SEG6_IPTUNNEL_SRH])
		return -EINVAL;

	tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
	tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);

	/* tuninfo must contain at least the iptunnel encap structure,
	 * the SRH and one segment
	 */
	min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
		   sizeof(struct in6_addr);
	if (tuninfo_len < min_size)
		return -EINVAL;

	switch (tuninfo->mode) {
#ifdef CONFIG_IPV6_SEG6_INLINE
	case SEG6_IPTUN_MODE_INLINE:
		break;
#endif
	case SEG6_IPTUN_MODE_ENCAP:
		break;
	default:
		return -EINVAL;
	}

	/* verify that SRH is consistent */
	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
		return -EINVAL;

	newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
	if (!newts)
		return -ENOMEM;

	slwt = seg6_lwt_lwtunnel(newts);

#ifdef CONFIG_DST_CACHE
	err = dst_cache_init(&slwt->cache, GFP_KERNEL);
	if (err) {
		kfree(newts);
		return err;
	}
#endif

	memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);

	newts->type = LWTUNNEL_ENCAP_SEG6;
	newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT |
			LWTUNNEL_STATE_INPUT_REDIRECT;
	newts->headroom = seg6_lwt_headroom(tuninfo);

	*ts = newts;

	return 0;
}

#ifdef CONFIG_DST_CACHE
static void seg6_destroy_state(struct lwtunnel_state *lwt)
{
	dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
}
#endif

static int seg6_fill_encap_info(struct sk_buff *skb,
				struct lwtunnel_state *lwtstate)
{
	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);

	if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
		return -EMSGSIZE;

	return 0;
}

static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
{
	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);

	return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
}

static int seg6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
{
	struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
	struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
	int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);

	if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
		return 1;

	return memcmp(a_hdr, b_hdr, len);
}

static const struct lwtunnel_encap_ops seg6_iptun_ops = {
	.build_state = seg6_build_state,
#ifdef CONFIG_DST_CACHE
	.destroy_state = seg6_destroy_state,
#endif
	.output = seg6_output,
	.input = seg6_input,
	.fill_encap = seg6_fill_encap_info,
	.get_encap_size = seg6_encap_nlsize,
	.cmp_encap = seg6_encap_cmp,
};

int __init seg6_iptunnel_init(void)
{
	return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
}

void seg6_iptunnel_exit(void)
{
	lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
}
Commit	Line	Data
6c8702c6 DL	1	/*
	2	* SR-IPv6 implementation
	3	*
	4	* Author:
	5	* David Lebrun <david.lebrun@uclouvain.be>
	6	*
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13
	14	#include <linux/types.h>
	15	#include <linux/skbuff.h>
	16	#include <linux/net.h>
	17	#include <linux/module.h>
	18	#include <net/ip.h>
	19	#include <net/lwtunnel.h>
	20	#include <net/netevent.h>
	21	#include <net/netns/generic.h>
	22	#include <net/ip6_fib.h>
	23	#include <net/route.h>
	24	#include <net/seg6.h>
	25	#include <linux/seg6.h>
	26	#include <linux/seg6_iptunnel.h>
	27	#include <net/addrconf.h>
	28	#include <net/ip6_route.h>
	29	#ifdef CONFIG_DST_CACHE
	30	#include <net/dst_cache.h>
	31	#endif
9baee834 DL	32	#ifdef CONFIG_IPV6_SEG6_HMAC
	33	#include <net/seg6_hmac.h>
	34	#endif
6c8702c6 DL	35
	36	struct seg6_lwt {
	37	#ifdef CONFIG_DST_CACHE
	38	struct dst_cache cache;
	39	#endif
	40	struct seg6_iptunnel_encap tuninfo[0];
	41	};
	42
	43	static inline struct seg6_lwt seg6_lwt_lwtunnel(struct lwtunnel_state lwt)
	44	{
	45	return (struct seg6_lwt *)lwt->data;
	46	}
	47
	48	static inline struct seg6_iptunnel_encap *
	49	seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
	50	{
	51	return seg6_lwt_lwtunnel(lwt)->tuninfo;
	52	}
	53
	54	static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
	55	[SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
	56	};
	57
	58	int nla_put_srh(struct sk_buff *skb, int attrtype,
	59	struct seg6_iptunnel_encap *tuninfo)
	60	{
	61	struct seg6_iptunnel_encap *data;
	62	struct nlattr *nla;
	63	int len;
	64
	65	len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
	66
	67	nla = nla_reserve(skb, attrtype, len);
	68	if (!nla)
	69	return -EMSGSIZE;
	70
	71	data = nla_data(nla);
	72	memcpy(data, tuninfo, len);
	73
	74	return 0;
	75	}
	76
	77	static void set_tun_src(struct net net, struct net_device dev,
	78	struct in6_addr daddr, struct in6_addr saddr)
	79	{
	80	struct seg6_pernet_data *sdata = seg6_pernet(net);
	81	struct in6_addr *tun_src;
	82
	83	rcu_read_lock();
	84
	85	tun_src = rcu_dereference(sdata->tun_src);
	86
	87	if (!ipv6_addr_any(tun_src)) {
	88	memcpy(saddr, tun_src, sizeof(struct in6_addr));
	89	} else {
	90	ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
	91	saddr);
	92	}
	93
	94	rcu_read_unlock();
	95	}
	96
	97	/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
	98	static int seg6_do_srh_encap(struct sk_buff skb, struct ipv6_sr_hdr osrh)
99	{
100	struct net *net = dev_net(skb_dst(skb)->dev);
101	struct ipv6hdr hdr, inner_hdr;
102	struct ipv6_sr_hdr *isrh;
103	int hdrlen, tot_len, err;
104
105	hdrlen = (osrh->hdrlen + 1) << 3;
106	tot_len = hdrlen + sizeof(*hdr);
107
108	err = pskb_expand_head(skb, tot_len, 0, GFP_ATOMIC);
109	if (unlikely(err))
110	return err;
111
112	inner_hdr = ipv6_hdr(skb);
113
114	skb_push(skb, tot_len);
115	skb_reset_network_header(skb);
116	skb_mac_header_rebuild(skb);
117	hdr = ipv6_hdr(skb);
118
119	/* inherit tc, flowlabel and hlim
120	* hlim will be decremented in ip6_forward() afterwards and
121	* decapsulation will overwrite inner hlim with outer hlim
122	*/
123	ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
124	ip6_flowlabel(inner_hdr));
125	hdr->hop_limit = inner_hdr->hop_limit;
126	hdr->nexthdr = NEXTHDR_ROUTING;
127
128	isrh = (void )hdr + sizeof(hdr);
129	memcpy(isrh, osrh, hdrlen);
130
131	isrh->nexthdr = NEXTHDR_IPV6;
132
133	hdr->daddr = isrh->segments[isrh->first_segment];
134	set_tun_src(net, skb->dev, &hdr->daddr, &hdr->saddr);
135
9baee834 DL	136	#ifdef CONFIG_IPV6_SEG6_HMAC
	137	if (sr_has_hmac(isrh)) {
	138	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	139	if (unlikely(err))
	140	return err;
	141	}
	142	#endif
	143
6c8702c6 DL	144	skb_postpush_rcsum(skb, hdr, tot_len);
	145
	146	return 0;
	147	}
	148
	149	/* insert an SRH within an IPv6 packet, just after the IPv6 header */
	150	#ifdef CONFIG_IPV6_SEG6_INLINE
	151	static int seg6_do_srh_inline(struct sk_buff skb, struct ipv6_sr_hdr osrh)
	152	{
	153	struct ipv6hdr hdr, oldhdr;
	154	struct ipv6_sr_hdr *isrh;
	155	int hdrlen, err;
	156
	157	hdrlen = (osrh->hdrlen + 1) << 3;
	158
	159	err = pskb_expand_head(skb, hdrlen, 0, GFP_ATOMIC);
	160	if (unlikely(err))
	161	return err;
	162
	163	oldhdr = ipv6_hdr(skb);
	164
	165	skb_pull(skb, sizeof(struct ipv6hdr));
	166	skb_postpull_rcsum(skb, skb_network_header(skb),
	167	sizeof(struct ipv6hdr));
	168
	169	skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
	170	skb_reset_network_header(skb);
	171	skb_mac_header_rebuild(skb);
	172
	173	hdr = ipv6_hdr(skb);
	174
	175	memmove(hdr, oldhdr, sizeof(*hdr));
	176
	177	isrh = (void )hdr + sizeof(hdr);
	178	memcpy(isrh, osrh, hdrlen);
	179
	180	isrh->nexthdr = hdr->nexthdr;
	181	hdr->nexthdr = NEXTHDR_ROUTING;
	182
	183	isrh->segments[0] = hdr->daddr;
	184	hdr->daddr = isrh->segments[isrh->first_segment];
	185
9baee834 DL	186	#ifdef CONFIG_IPV6_SEG6_HMAC
	187	if (sr_has_hmac(isrh)) {
	188	struct net *net = dev_net(skb_dst(skb)->dev);
	189
	190	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	191	if (unlikely(err))
	192	return err;
	193	}
	194	#endif
	195
6c8702c6 DL	196	skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
	197
	198	return 0;
	199	}
	200	#endif
	201
	202	static int seg6_do_srh(struct sk_buff *skb)
	203	{
	204	struct dst_entry *dst = skb_dst(skb);
	205	struct seg6_iptunnel_encap *tinfo;
	206	int err = 0;
	207
	208	tinfo = seg6_encap_lwtunnel(dst->lwtstate);
	209
	210	if (likely(!skb->encapsulation)) {
	211	skb_reset_inner_headers(skb);
	212	skb->encapsulation = 1;
	213	}
	214
	215	switch (tinfo->mode) {
	216	#ifdef CONFIG_IPV6_SEG6_INLINE
	217	case SEG6_IPTUN_MODE_INLINE:
	218	err = seg6_do_srh_inline(skb, tinfo->srh);
	219	skb_reset_inner_headers(skb);
	220	break;
	221	#endif
	222	case SEG6_IPTUN_MODE_ENCAP:
	223	err = seg6_do_srh_encap(skb, tinfo->srh);
	224	break;
	225	}
	226
	227	if (err)
	228	return err;
	229
	230	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	231	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
	232
	233	skb_set_inner_protocol(skb, skb->protocol);
	234
	235	return 0;
	236	}
	237
	238	int seg6_input(struct sk_buff *skb)
	239	{
	240	int err;
	241
	242	err = seg6_do_srh(skb);
	243	if (unlikely(err)) {
	244	kfree_skb(skb);
	245	return err;
	246	}
	247
	248	skb_dst_drop(skb);
	249	ip6_route_input(skb);
	250
	251	return dst_input(skb);
	252	}
	253
	254	int seg6_output(struct net net, struct sock sk, struct sk_buff *skb)
	255	{
	256	struct dst_entry *orig_dst = skb_dst(skb);
	257	struct dst_entry *dst = NULL;
	258	struct seg6_lwt *slwt;
	259	int err = -EINVAL;
260
261	err = seg6_do_srh(skb);
262	if (unlikely(err))
263	goto drop;
264
265	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
266
267	#ifdef CONFIG_DST_CACHE
268	dst = dst_cache_get(&slwt->cache);
269	#endif
270
271	if (unlikely(!dst)) {
272	struct ipv6hdr *hdr = ipv6_hdr(skb);
273	struct flowi6 fl6;
274
275	fl6.daddr = hdr->daddr;
276	fl6.saddr = hdr->saddr;
277	fl6.flowlabel = ip6_flowinfo(hdr);
278	fl6.flowi6_mark = skb->mark;
279	fl6.flowi6_proto = hdr->nexthdr;
280
281	dst = ip6_route_output(net, NULL, &fl6);
282	if (dst->error) {
283	err = dst->error;
284	dst_release(dst);
285	goto drop;
286	}
287
288	#ifdef CONFIG_DST_CACHE
289	dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
290	#endif
291	}
292
293	skb_dst_drop(skb);
294	skb_dst_set(skb, dst);
295
296	return dst_output(net, sk, skb);
297	drop:
298	kfree_skb(skb);
299	return err;
300	}
301
302	static int seg6_build_state(struct net_device dev, struct nlattr nla,
303	unsigned int family, const void *cfg,
304	struct lwtunnel_state **ts)
305	{
306	struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
307	struct seg6_iptunnel_encap *tuninfo;
308	struct lwtunnel_state *newts;
309	int tuninfo_len, min_size;
310	struct seg6_lwt *slwt;
311	int err;
312
313	err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
314	seg6_iptunnel_policy);
315
316	if (err < 0)
317	return err;
318
319	if (!tb[SEG6_IPTUNNEL_SRH])
320	return -EINVAL;
321
322	tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
323	tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
324
325	/* tuninfo must contain at least the iptunnel encap structure,
326	* the SRH and one segment
327	*/
328	min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
329	sizeof(struct in6_addr);
330	if (tuninfo_len < min_size)
331	return -EINVAL;
332
333	switch (tuninfo->mode) {
334	#ifdef CONFIG_IPV6_SEG6_INLINE
335	case SEG6_IPTUN_MODE_INLINE:
336	break;
337	#endif
338	case SEG6_IPTUN_MODE_ENCAP:
339	break;
340	default:
341	return -EINVAL;
342	}
343
344	/* verify that SRH is consistent */
345	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
346	return -EINVAL;
347
348	newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
349	if (!newts)
350	return -ENOMEM;
351
352	slwt = seg6_lwt_lwtunnel(newts);
353
354	#ifdef CONFIG_DST_CACHE
355	err = dst_cache_init(&slwt->cache, GFP_KERNEL);
356	if (err) {
357	kfree(newts);
358	return err;
359	}
360	#endif
361
362	memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
363
364	newts->type = LWTUNNEL_ENCAP_SEG6;
365	newts->flags \|= LWTUNNEL_STATE_OUTPUT_REDIRECT \|
366	LWTUNNEL_STATE_INPUT_REDIRECT;
367	newts->headroom = seg6_lwt_headroom(tuninfo);
368
369	*ts = newts;
370
371	return 0;
372	}
373
374	#ifdef CONFIG_DST_CACHE
375	static void seg6_destroy_state(struct lwtunnel_state *lwt)
376	{
377	dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
378	}
379	#endif
380
381	static int seg6_fill_encap_info(struct sk_buff *skb,
382	struct lwtunnel_state *lwtstate)
383	{
384	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
385
386	if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
387	return -EMSGSIZE;
388
389	return 0;
390	}
391
392	static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
393	{
394	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
395
396	return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
397	}
398
399	static int seg6_encap_cmp(struct lwtunnel_state a, struct lwtunnel_state b)
400	{
401	struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
402	struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
403	int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
404
405	if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
406	return 1;
407
408	return memcmp(a_hdr, b_hdr, len);
409	}
410
411	static const struct lwtunnel_encap_ops seg6_iptun_ops = {
412	.build_state = seg6_build_state,
413	#ifdef CONFIG_DST_CACHE
414	.destroy_state = seg6_destroy_state,
415	#endif
416	.output = seg6_output,
417	.input = seg6_input,
418	.fill_encap = seg6_fill_encap_info,
419	.get_encap_size = seg6_encap_nlsize,
420	.cmp_encap = seg6_encap_cmp,
421	};
422
423	int __init seg6_iptunnel_init(void)
424	{
425	return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
426	}
427
428	void seg6_iptunnel_exit(void)
429	{
430	lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
431	}