[linux-block.git] / net / ipv6 / rpl_iptunnel.c

// SPDX-License-Identifier: GPL-2.0-only
/**
 * Authors:
 * (C) 2020 Alexander Aring <alex.aring@gmail.com>
 */

#include <linux/rpl_iptunnel.h>

#include <net/dst_cache.h>
#include <net/ip6_route.h>
#include <net/lwtunnel.h>
#include <net/ipv6.h>
#include <net/rpl.h>

struct rpl_iptunnel_encap {
	struct ipv6_rpl_sr_hdr srh[0];
};

struct rpl_lwt {
	struct dst_cache cache;
	struct rpl_iptunnel_encap tuninfo;
};

static inline struct rpl_lwt *rpl_lwt_lwtunnel(struct lwtunnel_state *lwt)
{
	return (struct rpl_lwt *)lwt->data;
}

static inline struct rpl_iptunnel_encap *
rpl_encap_lwtunnel(struct lwtunnel_state *lwt)
{
	return &rpl_lwt_lwtunnel(lwt)->tuninfo;
}

static const struct nla_policy rpl_iptunnel_policy[RPL_IPTUNNEL_MAX + 1] = {
	[RPL_IPTUNNEL_SRH]	= { .type = NLA_BINARY },
};

static bool rpl_validate_srh(struct net *net, struct ipv6_rpl_sr_hdr *srh,
			     size_t seglen)
{
	int err;

	if ((srh->hdrlen << 3) != seglen)
		return false;

	/* check at least one segment and seglen fit with segments_left */
	if (!srh->segments_left ||
	    (srh->segments_left * sizeof(struct in6_addr)) != seglen)
		return false;

	if (srh->cmpri || srh->cmpre)
		return false;

	err = ipv6_chk_rpl_srh_loop(net, srh->rpl_segaddr,
				    srh->segments_left);
	if (err)
		return false;

	if (ipv6_addr_type(&srh->rpl_segaddr[srh->segments_left - 1]) &
	    IPV6_ADDR_MULTICAST)
		return false;

	return true;
}

static int rpl_build_state(struct net *net, struct nlattr *nla,
			   unsigned int family, const void *cfg,
			   struct lwtunnel_state **ts,
			   struct netlink_ext_ack *extack)
{
	struct nlattr *tb[RPL_IPTUNNEL_MAX + 1];
	struct lwtunnel_state *newts;
	struct ipv6_rpl_sr_hdr *srh;
	struct rpl_lwt *rlwt;
	int err, srh_len;

	if (family != AF_INET6)
		return -EINVAL;

	err = nla_parse_nested(tb, RPL_IPTUNNEL_MAX, nla,
			       rpl_iptunnel_policy, extack);
	if (err < 0)
		return err;

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

	srh = nla_data(tb[RPL_IPTUNNEL_SRH]);
	srh_len = nla_len(tb[RPL_IPTUNNEL_SRH]);

	if (srh_len < sizeof(*srh))
		return -EINVAL;

	/* verify that SRH is consistent */
	if (!rpl_validate_srh(net, srh, srh_len - sizeof(*srh)))
		return -EINVAL;

	newts = lwtunnel_state_alloc(srh_len + sizeof(*rlwt));
	if (!newts)
		return -ENOMEM;

	rlwt = rpl_lwt_lwtunnel(newts);

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

	memcpy(&rlwt->tuninfo.srh, srh, srh_len);

	newts->type = LWTUNNEL_ENCAP_RPL;
	newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;
	newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;

	*ts = newts;

	return 0;
}

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

static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rlwt,
			     const struct ipv6_rpl_sr_hdr *srh)
{
	struct ipv6_rpl_sr_hdr *isrh, *csrh;
	const struct ipv6hdr *oldhdr;
	struct ipv6hdr *hdr;
	unsigned char *buf;
	size_t hdrlen;
	int err;

	oldhdr = ipv6_hdr(skb);

	buf = kzalloc(ipv6_rpl_srh_alloc_size(srh->segments_left - 1) * 2,
		      GFP_ATOMIC);
	if (!buf)
		return -ENOMEM;

	isrh = (struct ipv6_rpl_sr_hdr *)buf;
	csrh = (struct ipv6_rpl_sr_hdr *)(buf + ((srh->hdrlen + 1) << 3));

	memcpy(isrh, srh, sizeof(*isrh));
	memcpy(isrh->rpl_segaddr, &srh->rpl_segaddr[1],
	       (srh->segments_left - 1) * 16);
	isrh->rpl_segaddr[srh->segments_left - 1] = oldhdr->daddr;

	ipv6_rpl_srh_compress(csrh, isrh, &srh->rpl_segaddr[0],
			      isrh->segments_left - 1);

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

	err = skb_cow_head(skb, hdrlen + skb->mac_len);
	if (unlikely(err)) {
		kfree(buf);
		return err;
	}

	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, csrh, hdrlen);

	isrh->nexthdr = hdr->nexthdr;
	hdr->nexthdr = NEXTHDR_ROUTING;
	hdr->daddr = srh->rpl_segaddr[0];

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

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

	kfree(buf);

	return 0;
}

static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt)
{
	struct dst_entry *dst = skb_dst(skb);
	struct rpl_iptunnel_encap *tinfo;
	int err = 0;

	if (skb->protocol != htons(ETH_P_IPV6))
		return -EINVAL;

	tinfo = rpl_encap_lwtunnel(dst->lwtstate);

	err = rpl_do_srh_inline(skb, rlwt, tinfo->srh);
	if (err)
		return err;

	return 0;
}

static int rpl_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 rpl_lwt *rlwt;
	int err;

	rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);

	err = rpl_do_srh(skb, rlwt);
	if (unlikely(err))
		goto drop;

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

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

		memset(&fl6, 0, sizeof(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(&rlwt->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 rpl_input(struct sk_buff *skb)
{
	struct dst_entry *orig_dst = skb_dst(skb);
	struct dst_entry *dst = NULL;
	struct rpl_lwt *rlwt;
	int err;

	rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);

	err = rpl_do_srh(skb, rlwt);
	if (unlikely(err)) {
		kfree_skb(skb);
		return err;
	}

	preempt_disable();
	dst = dst_cache_get(&rlwt->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(&rlwt->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 nla_put_rpl_srh(struct sk_buff *skb, int attrtype,
			   struct rpl_iptunnel_encap *tuninfo)
{
	struct rpl_iptunnel_encap *data;
	struct nlattr *nla;
	int len;

	len = RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh);

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

	data = nla_data(nla);
	memcpy(data, tuninfo->srh, len);

	return 0;
}

static int rpl_fill_encap_info(struct sk_buff *skb,
			       struct lwtunnel_state *lwtstate)
{
	struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);

	if (nla_put_rpl_srh(skb, RPL_IPTUNNEL_SRH, tuninfo))
		return -EMSGSIZE;

	return 0;
}

static int rpl_encap_nlsize(struct lwtunnel_state *lwtstate)
{
	struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);

	return nla_total_size(RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh));
}

static int rpl_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b)
{
	struct rpl_iptunnel_encap *a_hdr = rpl_encap_lwtunnel(a);
	struct rpl_iptunnel_encap *b_hdr = rpl_encap_lwtunnel(b);
	int len = RPL_IPTUNNEL_SRH_SIZE(a_hdr->srh);

	if (len != RPL_IPTUNNEL_SRH_SIZE(b_hdr->srh))
		return 1;

	return memcmp(a_hdr, b_hdr, len);
}

static const struct lwtunnel_encap_ops rpl_ops = {
	.build_state	= rpl_build_state,
	.destroy_state	= rpl_destroy_state,
	.output		= rpl_output,
	.input		= rpl_input,
	.fill_encap	= rpl_fill_encap_info,
	.get_encap_size	= rpl_encap_nlsize,
	.cmp_encap	= rpl_encap_cmp,
	.owner		= THIS_MODULE,
};

int __init rpl_init(void)
{
	int err;

	err = lwtunnel_encap_add_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);
	if (err)
		goto out;

	pr_info("RPL Segment Routing with IPv6\n");

	return 0;

out:
	return err;
}

void rpl_exit(void)
{
	lwtunnel_encap_del_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);
}
Commit	Line	Data
a7a29f9c AA	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/**
	3	* Authors:
	4	* (C) 2020 Alexander Aring <alex.aring@gmail.com>
	5	*/
	6
	7	#include <linux/rpl_iptunnel.h>
	8
	9	#include <net/dst_cache.h>
	10	#include <net/ip6_route.h>
	11	#include <net/lwtunnel.h>
	12	#include <net/ipv6.h>
	13	#include <net/rpl.h>
	14
	15	struct rpl_iptunnel_encap {
	16	struct ipv6_rpl_sr_hdr srh[0];
	17	};
	18
	19	struct rpl_lwt {
	20	struct dst_cache cache;
	21	struct rpl_iptunnel_encap tuninfo;
	22	};
	23
	24	static inline struct rpl_lwt rpl_lwt_lwtunnel(struct lwtunnel_state lwt)
	25	{
	26	return (struct rpl_lwt *)lwt->data;
	27	}
	28
	29	static inline struct rpl_iptunnel_encap *
	30	rpl_encap_lwtunnel(struct lwtunnel_state *lwt)
	31	{
	32	return &rpl_lwt_lwtunnel(lwt)->tuninfo;
	33	}
	34
	35	static const struct nla_policy rpl_iptunnel_policy[RPL_IPTUNNEL_MAX + 1] = {
	36	[RPL_IPTUNNEL_SRH] = { .type = NLA_BINARY },
	37	};
	38
	39	static bool rpl_validate_srh(struct net net, struct ipv6_rpl_sr_hdr srh,
	40	size_t seglen)
	41	{
	42	int err;
	43
	44	if ((srh->hdrlen << 3) != seglen)
	45	return false;
	46
	47	/* check at least one segment and seglen fit with segments_left */
	48	if (!srh->segments_left \|\|
	49	(srh->segments_left * sizeof(struct in6_addr)) != seglen)
	50	return false;
	51
	52	if (srh->cmpri \|\| srh->cmpre)
	53	return false;
	54
	55	err = ipv6_chk_rpl_srh_loop(net, srh->rpl_segaddr,
	56	srh->segments_left);
	57	if (err)
	58	return false;
	59
	60	if (ipv6_addr_type(&srh->rpl_segaddr[srh->segments_left - 1]) &
	61	IPV6_ADDR_MULTICAST)
	62	return false;
	63
	64	return true;
65	}
66
67	static int rpl_build_state(struct net net, struct nlattr nla,
68	unsigned int family, const void *cfg,
69	struct lwtunnel_state **ts,
70	struct netlink_ext_ack *extack)
71	{
72	struct nlattr *tb[RPL_IPTUNNEL_MAX + 1];
73	struct lwtunnel_state *newts;
74	struct ipv6_rpl_sr_hdr *srh;
75	struct rpl_lwt *rlwt;
76	int err, srh_len;
77
78	if (family != AF_INET6)
79	return -EINVAL;
80
81	err = nla_parse_nested(tb, RPL_IPTUNNEL_MAX, nla,
82	rpl_iptunnel_policy, extack);
83	if (err < 0)
84	return err;
85
86	if (!tb[RPL_IPTUNNEL_SRH])
87	return -EINVAL;
88
89	srh = nla_data(tb[RPL_IPTUNNEL_SRH]);
90	srh_len = nla_len(tb[RPL_IPTUNNEL_SRH]);
91
92	if (srh_len < sizeof(*srh))
93	return -EINVAL;
94
95	/* verify that SRH is consistent */
96	if (!rpl_validate_srh(net, srh, srh_len - sizeof(*srh)))
97	return -EINVAL;
98
99	newts = lwtunnel_state_alloc(srh_len + sizeof(*rlwt));
100	if (!newts)
101	return -ENOMEM;
102
103	rlwt = rpl_lwt_lwtunnel(newts);
104
105	err = dst_cache_init(&rlwt->cache, GFP_ATOMIC);
106	if (err) {
107	kfree(newts);
108	return err;
109	}
110
111	memcpy(&rlwt->tuninfo.srh, srh, srh_len);
112
113	newts->type = LWTUNNEL_ENCAP_RPL;
114	newts->flags \|= LWTUNNEL_STATE_INPUT_REDIRECT;
115	newts->flags \|= LWTUNNEL_STATE_OUTPUT_REDIRECT;
116
117	*ts = newts;
118
119	return 0;
120	}
121
122	static void rpl_destroy_state(struct lwtunnel_state *lwt)
123	{
124	dst_cache_destroy(&rpl_lwt_lwtunnel(lwt)->cache);
125	}
126
127	static int rpl_do_srh_inline(struct sk_buff skb, const struct rpl_lwt rlwt,
128	const struct ipv6_rpl_sr_hdr *srh)
129	{
130	struct ipv6_rpl_sr_hdr isrh, csrh;
131	const struct ipv6hdr *oldhdr;
132	struct ipv6hdr *hdr;
133	unsigned char *buf;
134	size_t hdrlen;
135	int err;
136
137	oldhdr = ipv6_hdr(skb);
138
139	buf = kzalloc(ipv6_rpl_srh_alloc_size(srh->segments_left - 1) * 2,
140	GFP_ATOMIC);
141	if (!buf)
142	return -ENOMEM;
143
144	isrh = (struct ipv6_rpl_sr_hdr *)buf;
145	csrh = (struct ipv6_rpl_sr_hdr *)(buf + ((srh->hdrlen + 1) << 3));
146
147	memcpy(isrh, srh, sizeof(*isrh));
148	memcpy(isrh->rpl_segaddr, &srh->rpl_segaddr[1],
149	(srh->segments_left - 1) * 16);
150	isrh->rpl_segaddr[srh->segments_left - 1] = oldhdr->daddr;
151
152	ipv6_rpl_srh_compress(csrh, isrh, &srh->rpl_segaddr[0],
153	isrh->segments_left - 1);
154
155	hdrlen = ((csrh->hdrlen + 1) << 3);
156
157	err = skb_cow_head(skb, hdrlen + skb->mac_len);
7f80ccfe GS	158	if (unlikely(err)) {
7f80ccfe GS	159	kfree(buf);
a7a29f9c	160	return err;
7f80ccfe	161	}
a7a29f9c AA	162
	163	skb_pull(skb, sizeof(struct ipv6hdr));
	164	skb_postpull_rcsum(skb, skb_network_header(skb),
	165	sizeof(struct ipv6hdr));
	166
	167	skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
	168	skb_reset_network_header(skb);
	169	skb_mac_header_rebuild(skb);
	170
	171	hdr = ipv6_hdr(skb);
	172	memmove(hdr, oldhdr, sizeof(*hdr));
	173	isrh = (void )hdr + sizeof(hdr);
	174	memcpy(isrh, csrh, hdrlen);
	175
	176	isrh->nexthdr = hdr->nexthdr;
	177	hdr->nexthdr = NEXTHDR_ROUTING;
	178	hdr->daddr = srh->rpl_segaddr[0];
	179
	180	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	181	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
	182
	183	skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
	184
	185	kfree(buf);
	186
	187	return 0;
	188	}
	189
	190	static int rpl_do_srh(struct sk_buff skb, const struct rpl_lwt rlwt)
	191	{
	192	struct dst_entry *dst = skb_dst(skb);
	193	struct rpl_iptunnel_encap *tinfo;
	194	int err = 0;
	195
	196	if (skb->protocol != htons(ETH_P_IPV6))
	197	return -EINVAL;
	198
	199	tinfo = rpl_encap_lwtunnel(dst->lwtstate);
	200
	201	err = rpl_do_srh_inline(skb, rlwt, tinfo->srh);
	202	if (err)
	203	return err;
	204
	205	return 0;
	206	}
	207
	208	static int rpl_output(struct net net, struct sock sk, struct sk_buff *skb)
	209	{
	210	struct dst_entry *orig_dst = skb_dst(skb);
	211	struct dst_entry *dst = NULL;
	212	struct rpl_lwt *rlwt;
d16fa759	213	int err;
a7a29f9c AA	214
	215	rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);
	216
	217	err = rpl_do_srh(skb, rlwt);
	218	if (unlikely(err))
	219	goto drop;
	220
	221	preempt_disable();
	222	dst = dst_cache_get(&rlwt->cache);
	223	preempt_enable();
	224
	225	if (unlikely(!dst)) {
	226	struct ipv6hdr *hdr = ipv6_hdr(skb);
	227	struct flowi6 fl6;
	228
	229	memset(&fl6, 0, sizeof(fl6));
	230	fl6.daddr = hdr->daddr;
	231	fl6.saddr = hdr->saddr;
	232	fl6.flowlabel = ip6_flowinfo(hdr);
	233	fl6.flowi6_mark = skb->mark;
	234	fl6.flowi6_proto = hdr->nexthdr;
	235
	236	dst = ip6_route_output(net, NULL, &fl6);
	237	if (dst->error) {
	238	err = dst->error;
	239	dst_release(dst);
	240	goto drop;
	241	}
	242
	243	preempt_disable();
	244	dst_cache_set_ip6(&rlwt->cache, dst, &fl6.saddr);
	245	preempt_enable();
	246	}
	247
	248	skb_dst_drop(skb);
	249	skb_dst_set(skb, dst);
	250
	251	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	252	if (unlikely(err))
	253	goto drop;
	254
	255	return dst_output(net, sk, skb);
	256
	257	drop:
	258	kfree_skb(skb);
	259	return err;
	260	}
	261
	262	static int rpl_input(struct sk_buff *skb)
	263	{
	264	struct dst_entry *orig_dst = skb_dst(skb);
	265	struct dst_entry *dst = NULL;
	266	struct rpl_lwt *rlwt;
	267	int err;
	268
	269	rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate);
	270
	271	err = rpl_do_srh(skb, rlwt);
	272	if (unlikely(err)) {
	273	kfree_skb(skb);
	274	return err;
	275	}
	276
	277	preempt_disable();
278	dst = dst_cache_get(&rlwt->cache);
279	preempt_enable();
280
281	skb_dst_drop(skb);
282
283	if (!dst) {
284	ip6_route_input(skb);
285	dst = skb_dst(skb);
286	if (!dst->error) {
287	preempt_disable();
288	dst_cache_set_ip6(&rlwt->cache, dst,
289	&ipv6_hdr(skb)->saddr);
290	preempt_enable();
291	}
292	} else {
293	skb_dst_set(skb, dst);
294	}
295
296	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
297	if (unlikely(err))
298	return err;
299
300	return dst_input(skb);
301	}
302
303	static int nla_put_rpl_srh(struct sk_buff *skb, int attrtype,
304	struct rpl_iptunnel_encap *tuninfo)
305	{
306	struct rpl_iptunnel_encap *data;
307	struct nlattr *nla;
308	int len;
309
310	len = RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh);
311
312	nla = nla_reserve(skb, attrtype, len);
313	if (!nla)
314	return -EMSGSIZE;
315
316	data = nla_data(nla);
317	memcpy(data, tuninfo->srh, len);
318
319	return 0;
320	}
321
322	static int rpl_fill_encap_info(struct sk_buff *skb,
323	struct lwtunnel_state *lwtstate)
324	{
325	struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);
326
327	if (nla_put_rpl_srh(skb, RPL_IPTUNNEL_SRH, tuninfo))
328	return -EMSGSIZE;
329
330	return 0;
331	}
332
333	static int rpl_encap_nlsize(struct lwtunnel_state *lwtstate)
334	{
335	struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate);
336
337	return nla_total_size(RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh));
338	}
339
340	static int rpl_encap_cmp(struct lwtunnel_state a, struct lwtunnel_state b)
341	{
342	struct rpl_iptunnel_encap *a_hdr = rpl_encap_lwtunnel(a);
343	struct rpl_iptunnel_encap *b_hdr = rpl_encap_lwtunnel(b);
344	int len = RPL_IPTUNNEL_SRH_SIZE(a_hdr->srh);
345
346	if (len != RPL_IPTUNNEL_SRH_SIZE(b_hdr->srh))
347	return 1;
348
349	return memcmp(a_hdr, b_hdr, len);
350	}
351
352	static const struct lwtunnel_encap_ops rpl_ops = {
353	.build_state = rpl_build_state,
354	.destroy_state = rpl_destroy_state,
355	.output = rpl_output,
356	.input = rpl_input,
357	.fill_encap = rpl_fill_encap_info,
358	.get_encap_size = rpl_encap_nlsize,
359	.cmp_encap = rpl_encap_cmp,
360	.owner = THIS_MODULE,
361	};
362
363	int __init rpl_init(void)
364	{
365	int err;
366
367	err = lwtunnel_encap_add_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);
368	if (err)
369	goto out;
370
371	pr_info("RPL Segment Routing with IPv6\n");
372
373	return 0;
374
375	out:
376	return err;
377	}
378
379	void rpl_exit(void)
380	{
381	lwtunnel_encap_del_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL);
382	}