[mirror_ubuntu-artful-kernel.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>
#include <net/dst_cache.h>
#ifdef CONFIG_IPV6_SEG6_HMAC
#include <net/seg6_hmac.h>
#endif

struct seg6_lwt {
	struct dst_cache cache;
	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 },
};

static 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 = skb_cow_head(skb, tot_len);
	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 = skb_cow_head(skb, hdrlen);
	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;
}

static int seg6_input(struct sk_buff *skb)
{
	struct dst_entry *orig_dst = skb_dst(skb);
	struct dst_entry *dst = NULL;
	struct seg6_lwt *slwt;
	int err;

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

	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);

	preempt_disable();
	dst = dst_cache_get(&slwt->cache);
	preempt_enable();

	skb_dst_drop(skb);

	if (!dst) {
		ip6_route_input(skb);
		dst = skb_dst(skb);
		if (!dst->error) {
			preempt_disable();
			dst_cache_set_ip6(&slwt->cache, dst,
					  &ipv6_hdr(skb)->saddr);
			preempt_enable();
		}
	} else {
		skb_dst_set(skb, dst);
	}

	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	if (unlikely(err))
		return err;

	return dst_input(skb);
}

static 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);

	preempt_disable();
	dst = dst_cache_get(&slwt->cache);
	preempt_enable();

	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;
		}

		preempt_disable();
		dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
		preempt_enable();
	}

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

	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	if (unlikely(err))
		goto drop;

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

static int seg6_build_state(struct nlattr *nla,
			    unsigned int family, const void *cfg,
			    struct lwtunnel_state **ts,
			    struct netlink_ext_ack *extack)
{
	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, extack);

	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);

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

	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;
}

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

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,
	.destroy_state = seg6_destroy_state,
	.output = seg6_output,
	.input = seg6_input,
	.fill_encap = seg6_fill_encap_info,
	.get_encap_size = seg6_encap_nlsize,
	.cmp_encap = seg6_encap_cmp,
	.owner = THIS_MODULE,
};

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>
6c8702c6	29	#include <net/dst_cache.h>
9baee834 DL	30	#ifdef CONFIG_IPV6_SEG6_HMAC
	31	#include <net/seg6_hmac.h>
	32	#endif
6c8702c6 DL	33
6c8702c6 DL	34	struct seg6_lwt {
6c8702c6	35	struct dst_cache cache;
6c8702c6 DL	36	struct seg6_iptunnel_encap tuninfo[0];
	37	};
	38
	39	static inline struct seg6_lwt seg6_lwt_lwtunnel(struct lwtunnel_state lwt)
	40	{
	41	return (struct seg6_lwt *)lwt->data;
	42	}
	43
	44	static inline struct seg6_iptunnel_encap *
	45	seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
	46	{
	47	return seg6_lwt_lwtunnel(lwt)->tuninfo;
	48	}
	49
	50	static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
	51	[SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
	52	};
	53
bb4005ba WY	54	static int nla_put_srh(struct sk_buff *skb, int attrtype,
bb4005ba WY	55	struct seg6_iptunnel_encap *tuninfo)
6c8702c6 DL	56	{
	57	struct seg6_iptunnel_encap *data;
	58	struct nlattr *nla;
	59	int len;
	60
	61	len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
	62
	63	nla = nla_reserve(skb, attrtype, len);
	64	if (!nla)
	65	return -EMSGSIZE;
	66
	67	data = nla_data(nla);
	68	memcpy(data, tuninfo, len);
	69
	70	return 0;
	71	}
	72
	73	static void set_tun_src(struct net net, struct net_device dev,
	74	struct in6_addr daddr, struct in6_addr saddr)
	75	{
	76	struct seg6_pernet_data *sdata = seg6_pernet(net);
	77	struct in6_addr *tun_src;
	78
	79	rcu_read_lock();
	80
	81	tun_src = rcu_dereference(sdata->tun_src);
	82
	83	if (!ipv6_addr_any(tun_src)) {
	84	memcpy(saddr, tun_src, sizeof(struct in6_addr));
	85	} else {
	86	ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
	87	saddr);
	88	}
	89
	90	rcu_read_unlock();
	91	}
	92
	93	/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
	94	static int seg6_do_srh_encap(struct sk_buff skb, struct ipv6_sr_hdr osrh)
	95	{
	96	struct net *net = dev_net(skb_dst(skb)->dev);
	97	struct ipv6hdr hdr, inner_hdr;
	98	struct ipv6_sr_hdr *isrh;
	99	int hdrlen, tot_len, err;
	100
	101	hdrlen = (osrh->hdrlen + 1) << 3;
	102	tot_len = hdrlen + sizeof(*hdr);
	103
19d5a26f	104	err = skb_cow_head(skb, tot_len);
6c8702c6 DL	105	if (unlikely(err))
	106	return err;
	107
	108	inner_hdr = ipv6_hdr(skb);
	109
	110	skb_push(skb, tot_len);
	111	skb_reset_network_header(skb);
	112	skb_mac_header_rebuild(skb);
	113	hdr = ipv6_hdr(skb);
	114
	115	/* inherit tc, flowlabel and hlim
	116	* hlim will be decremented in ip6_forward() afterwards and
	117	* decapsulation will overwrite inner hlim with outer hlim
	118	*/
	119	ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
	120	ip6_flowlabel(inner_hdr));
	121	hdr->hop_limit = inner_hdr->hop_limit;
	122	hdr->nexthdr = NEXTHDR_ROUTING;
	123
	124	isrh = (void )hdr + sizeof(hdr);
	125	memcpy(isrh, osrh, hdrlen);
	126
	127	isrh->nexthdr = NEXTHDR_IPV6;
	128
	129	hdr->daddr = isrh->segments[isrh->first_segment];
	130	set_tun_src(net, skb->dev, &hdr->daddr, &hdr->saddr);
	131
9baee834 DL	132	#ifdef CONFIG_IPV6_SEG6_HMAC
	133	if (sr_has_hmac(isrh)) {
	134	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	135	if (unlikely(err))
	136	return err;
	137	}
	138	#endif
	139
6c8702c6 DL	140	skb_postpush_rcsum(skb, hdr, tot_len);
	141
	142	return 0;
	143	}
	144
	145	/* insert an SRH within an IPv6 packet, just after the IPv6 header */
	146	#ifdef CONFIG_IPV6_SEG6_INLINE
	147	static int seg6_do_srh_inline(struct sk_buff skb, struct ipv6_sr_hdr osrh)
	148	{
	149	struct ipv6hdr hdr, oldhdr;
	150	struct ipv6_sr_hdr *isrh;
	151	int hdrlen, err;
	152
	153	hdrlen = (osrh->hdrlen + 1) << 3;
	154
19d5a26f	155	err = skb_cow_head(skb, hdrlen);
6c8702c6 DL	156	if (unlikely(err))
	157	return err;
	158
	159	oldhdr = ipv6_hdr(skb);
	160
	161	skb_pull(skb, sizeof(struct ipv6hdr));
	162	skb_postpull_rcsum(skb, skb_network_header(skb),
	163	sizeof(struct ipv6hdr));
	164
	165	skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
	166	skb_reset_network_header(skb);
	167	skb_mac_header_rebuild(skb);
	168
	169	hdr = ipv6_hdr(skb);
	170
	171	memmove(hdr, oldhdr, sizeof(*hdr));
	172
	173	isrh = (void )hdr + sizeof(hdr);
	174	memcpy(isrh, osrh, hdrlen);
	175
	176	isrh->nexthdr = hdr->nexthdr;
	177	hdr->nexthdr = NEXTHDR_ROUTING;
	178
	179	isrh->segments[0] = hdr->daddr;
	180	hdr->daddr = isrh->segments[isrh->first_segment];
	181
9baee834 DL	182	#ifdef CONFIG_IPV6_SEG6_HMAC
	183	if (sr_has_hmac(isrh)) {
	184	struct net *net = dev_net(skb_dst(skb)->dev);
	185
	186	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	187	if (unlikely(err))
	188	return err;
	189	}
	190	#endif
	191
6c8702c6 DL	192	skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
	193
	194	return 0;
	195	}
	196	#endif
	197
	198	static int seg6_do_srh(struct sk_buff *skb)
	199	{
	200	struct dst_entry *dst = skb_dst(skb);
	201	struct seg6_iptunnel_encap *tinfo;
	202	int err = 0;
	203
	204	tinfo = seg6_encap_lwtunnel(dst->lwtstate);
	205
	206	if (likely(!skb->encapsulation)) {
	207	skb_reset_inner_headers(skb);
	208	skb->encapsulation = 1;
	209	}
	210
	211	switch (tinfo->mode) {
	212	#ifdef CONFIG_IPV6_SEG6_INLINE
	213	case SEG6_IPTUN_MODE_INLINE:
	214	err = seg6_do_srh_inline(skb, tinfo->srh);
	215	skb_reset_inner_headers(skb);
	216	break;
	217	#endif
	218	case SEG6_IPTUN_MODE_ENCAP:
	219	err = seg6_do_srh_encap(skb, tinfo->srh);
	220	break;
	221	}
	222
	223	if (err)
	224	return err;
	225
	226	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	227	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
	228
	229	skb_set_inner_protocol(skb, skb->protocol);
	230
	231	return 0;
	232	}
	233
bb4005ba	234	static int seg6_input(struct sk_buff *skb)
6c8702c6	235	{
af4a2209 DL	236	struct dst_entry *orig_dst = skb_dst(skb);
	237	struct dst_entry *dst = NULL;
	238	struct seg6_lwt *slwt;
6c8702c6 DL	239	int err;
	240
	241	err = seg6_do_srh(skb);
	242	if (unlikely(err)) {
	243	kfree_skb(skb);
	244	return err;
	245	}
	246
af4a2209 DL	247	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
af4a2209 DL	248
af4a2209 DL	249	preempt_disable();
	250	dst = dst_cache_get(&slwt->cache);
	251	preempt_enable();
af4a2209	252
6c8702c6	253	skb_dst_drop(skb);
af4a2209 DL	254
	255	if (!dst) {
	256	ip6_route_input(skb);
af4a2209 DL	257	dst = skb_dst(skb);
	258	if (!dst->error) {
	259	preempt_disable();
	260	dst_cache_set_ip6(&slwt->cache, dst,
	261	&ipv6_hdr(skb)->saddr);
	262	preempt_enable();
	263	}
af4a2209 DL	264	} else {
	265	skb_dst_set(skb, dst);
	266	}
6c8702c6	267
af3b5158 DL	268	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	269	if (unlikely(err))
	270	return err;
	271
6c8702c6 DL	272	return dst_input(skb);
	273	}
	274
bb4005ba	275	static int seg6_output(struct net net, struct sock sk, struct sk_buff *skb)
6c8702c6 DL	276	{
	277	struct dst_entry *orig_dst = skb_dst(skb);
	278	struct dst_entry *dst = NULL;
	279	struct seg6_lwt *slwt;
	280	int err = -EINVAL;
	281
	282	err = seg6_do_srh(skb);
	283	if (unlikely(err))
	284	goto drop;
	285
	286	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
	287
fa79581e	288	preempt_disable();
6c8702c6	289	dst = dst_cache_get(&slwt->cache);
fa79581e	290	preempt_enable();
6c8702c6 DL	291
	292	if (unlikely(!dst)) {
	293	struct ipv6hdr *hdr = ipv6_hdr(skb);
	294	struct flowi6 fl6;
	295
	296	fl6.daddr = hdr->daddr;
	297	fl6.saddr = hdr->saddr;
	298	fl6.flowlabel = ip6_flowinfo(hdr);
	299	fl6.flowi6_mark = skb->mark;
	300	fl6.flowi6_proto = hdr->nexthdr;
	301
	302	dst = ip6_route_output(net, NULL, &fl6);
	303	if (dst->error) {
	304	err = dst->error;
	305	dst_release(dst);
	306	goto drop;
	307	}
	308
fa79581e	309	preempt_disable();
6c8702c6	310	dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
fa79581e	311	preempt_enable();
6c8702c6 DL	312	}
	313
	314	skb_dst_drop(skb);
	315	skb_dst_set(skb, dst);
	316
af3b5158 DL	317	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	318	if (unlikely(err))
	319	goto drop;
	320
6c8702c6 DL	321	return dst_output(net, sk, skb);
	322	drop:
	323	kfree_skb(skb);
	324	return err;
	325	}
	326
30357d7d	327	static int seg6_build_state(struct nlattr *nla,
6c8702c6	328	unsigned int family, const void *cfg,
9ae28727 DA	329	struct lwtunnel_state **ts,
9ae28727 DA	330	struct netlink_ext_ack *extack)
6c8702c6 DL	331	{
	332	struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
	333	struct seg6_iptunnel_encap *tuninfo;
	334	struct lwtunnel_state *newts;
	335	int tuninfo_len, min_size;
	336	struct seg6_lwt *slwt;
	337	int err;
	338
	339	err = nla_parse_nested(tb, SEG6_IPTUNNEL_MAX, nla,
9ae28727	340	seg6_iptunnel_policy, extack);
6c8702c6 DL	341
	342	if (err < 0)
	343	return err;
	344
	345	if (!tb[SEG6_IPTUNNEL_SRH])
	346	return -EINVAL;
	347
	348	tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
	349	tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
	350
	351	/* tuninfo must contain at least the iptunnel encap structure,
	352	* the SRH and one segment
	353	*/
	354	min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
	355	sizeof(struct in6_addr);
	356	if (tuninfo_len < min_size)
	357	return -EINVAL;
	358
	359	switch (tuninfo->mode) {
	360	#ifdef CONFIG_IPV6_SEG6_INLINE
	361	case SEG6_IPTUN_MODE_INLINE:
	362	break;
	363	#endif
	364	case SEG6_IPTUN_MODE_ENCAP:
	365	break;
	366	default:
	367	return -EINVAL;
	368	}
	369
	370	/* verify that SRH is consistent */
	371	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
	372	return -EINVAL;
	373
	374	newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
	375	if (!newts)
	376	return -ENOMEM;
	377
	378	slwt = seg6_lwt_lwtunnel(newts);
	379
6c8702c6 DL	380	err = dst_cache_init(&slwt->cache, GFP_KERNEL);
	381	if (err) {
	382	kfree(newts);
	383	return err;
	384	}
6c8702c6 DL	385
	386	memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
	387
	388	newts->type = LWTUNNEL_ENCAP_SEG6;
	389	newts->flags \|= LWTUNNEL_STATE_OUTPUT_REDIRECT \|
	390	LWTUNNEL_STATE_INPUT_REDIRECT;
	391	newts->headroom = seg6_lwt_headroom(tuninfo);
	392
	393	*ts = newts;
	394
	395	return 0;
	396	}
	397
6c8702c6 DL	398	static void seg6_destroy_state(struct lwtunnel_state *lwt)
	399	{
	400	dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
	401	}
6c8702c6 DL	402
	403	static int seg6_fill_encap_info(struct sk_buff *skb,
	404	struct lwtunnel_state *lwtstate)
	405	{
	406	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
	407
	408	if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
	409	return -EMSGSIZE;
	410
	411	return 0;
	412	}
	413
	414	static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
	415	{
	416	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
	417
	418	return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
	419	}
	420
	421	static int seg6_encap_cmp(struct lwtunnel_state a, struct lwtunnel_state b)
	422	{
	423	struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
	424	struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
	425	int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
	426
	427	if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
	428	return 1;
	429
	430	return memcmp(a_hdr, b_hdr, len);
	431	}
	432
	433	static const struct lwtunnel_encap_ops seg6_iptun_ops = {
	434	.build_state = seg6_build_state,
6c8702c6	435	.destroy_state = seg6_destroy_state,
6c8702c6 DL	436	.output = seg6_output,
	437	.input = seg6_input,
	438	.fill_encap = seg6_fill_encap_info,
	439	.get_encap_size = seg6_encap_nlsize,
	440	.cmp_encap = seg6_encap_cmp,
88ff7334	441	.owner = THIS_MODULE,
6c8702c6 DL	442	};
	443
	444	int __init seg6_iptunnel_init(void)
	445	{
	446	return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
	447	}
	448
	449	void seg6_iptunnel_exit(void)
	450	{
	451	lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
	452	}