[mirror_ubuntu-jammy-kernel.git] / net / ipv6 / seg6_iptunnel.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  SR-IPv6 implementation
 *
 *  Author:
 *  David Lebrun <david.lebrun@uclouvain.be>
 */

#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/net.h>
#include <linux/module.h>
#include <net/ip.h>
#include <net/ip_tunnels.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();
}

/* Compute flowlabel for outer IPv6 header */
static __be32 seg6_make_flowlabel(struct net *net, struct sk_buff *skb,
				  struct ipv6hdr *inner_hdr)
{
	int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
	__be32 flowlabel = 0;
	u32 hash;

	if (do_flowlabel > 0) {
		hash = skb_get_hash(skb);
		hash = rol32(hash, 16);
		flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
	} else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
		flowlabel = ip6_flowlabel(inner_hdr);
	}
	return flowlabel;
}

/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
int seg6_do_srh_encap(struct sk_buff *skb, struct ipv6_sr_hdr *osrh, int proto)
{
	struct dst_entry *dst = skb_dst(skb);
	struct net *net = dev_net(dst->dev);
	struct ipv6hdr *hdr, *inner_hdr;
	struct ipv6_sr_hdr *isrh;
	int hdrlen, tot_len, err;
	__be32 flowlabel;

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

	err = skb_cow_head(skb, tot_len + skb->mac_len);
	if (unlikely(err))
		return err;

	inner_hdr = ipv6_hdr(skb);
	flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);

	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
	 */

	if (skb->protocol == htons(ETH_P_IPV6)) {
		ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
			     flowlabel);
		hdr->hop_limit = inner_hdr->hop_limit;
	} else {
		ip6_flow_hdr(hdr, 0, flowlabel);
		hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));

		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
	}

	hdr->nexthdr = NEXTHDR_ROUTING;

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

	isrh->nexthdr = proto;

	hdr->daddr = isrh->segments[isrh->first_segment];
	set_tun_src(net, dst->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;
}
EXPORT_SYMBOL_GPL(seg6_do_srh_encap);

/* insert an SRH within an IPv6 packet, just after the IPv6 header */
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 + skb->mac_len);
	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;
}
EXPORT_SYMBOL_GPL(seg6_do_srh_inline);

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

	tinfo = seg6_encap_lwtunnel(dst->lwtstate);

	switch (tinfo->mode) {
	case SEG6_IPTUN_MODE_INLINE:
		if (skb->protocol != htons(ETH_P_IPV6))
			return -EINVAL;

		err = seg6_do_srh_inline(skb, tinfo->srh);
		if (err)
			return err;
		break;
	case SEG6_IPTUN_MODE_ENCAP:
		err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
		if (err)
			return err;

		if (skb->protocol == htons(ETH_P_IPV6))
			proto = IPPROTO_IPV6;
		else if (skb->protocol == htons(ETH_P_IP))
			proto = IPPROTO_IPIP;
		else
			return -EINVAL;

		err = seg6_do_srh_encap(skb, tinfo->srh, proto);
		if (err)
			return err;

		skb_set_inner_transport_header(skb, skb_transport_offset(skb));
		skb_set_inner_protocol(skb, skb->protocol);
		skb->protocol = htons(ETH_P_IPV6);
		break;
	case SEG6_IPTUN_MODE_L2ENCAP:
		if (!skb_mac_header_was_set(skb))
			return -EINVAL;

		if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
			return -ENOMEM;

		skb_mac_header_rebuild(skb);
		skb_push(skb, skb->mac_len);

		err = seg6_do_srh_encap(skb, tinfo->srh, IPPROTO_ETHERNET);
		if (err)
			return err;

		skb->protocol = htons(ETH_P_IPV6);
		break;
	}

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

	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;

		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(&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;

	if (family != AF_INET && family != AF_INET6)
		return -EINVAL;

	err = nla_parse_nested_deprecated(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) {
	case SEG6_IPTUN_MODE_INLINE:
		if (family != AF_INET6)
			return -EINVAL;

		break;
	case SEG6_IPTUN_MODE_ENCAP:
		break;
	case SEG6_IPTUN_MODE_L2ENCAP:
		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_ATOMIC);
	if (err) {
		kfree(newts);
		return err;
	}

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

	newts->type = LWTUNNEL_ENCAP_SEG6;
	newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT;

	if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
		newts->flags |= LWTUNNEL_STATE_OUTPUT_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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
6c8702c6 DL	2	/*
	3	* SR-IPv6 implementation
	4	*
	5	* Author:
	6	* David Lebrun <david.lebrun@uclouvain.be>
6c8702c6 DL	7	*/
	8
	9	#include <linux/types.h>
	10	#include <linux/skbuff.h>
	11	#include <linux/net.h>
	12	#include <linux/module.h>
	13	#include <net/ip.h>
5807b22c	14	#include <net/ip_tunnels.h>
6c8702c6 DL	15	#include <net/lwtunnel.h>
	16	#include <net/netevent.h>
	17	#include <net/netns/generic.h>
	18	#include <net/ip6_fib.h>
	19	#include <net/route.h>
	20	#include <net/seg6.h>
	21	#include <linux/seg6.h>
	22	#include <linux/seg6_iptunnel.h>
	23	#include <net/addrconf.h>
	24	#include <net/ip6_route.h>
6c8702c6	25	#include <net/dst_cache.h>
9baee834 DL	26	#ifdef CONFIG_IPV6_SEG6_HMAC
	27	#include <net/seg6_hmac.h>
	28	#endif
6c8702c6 DL	29
6c8702c6 DL	30	struct seg6_lwt {
6c8702c6	31	struct dst_cache cache;
6c8702c6 DL	32	struct seg6_iptunnel_encap tuninfo[0];
	33	};
	34
	35	static inline struct seg6_lwt seg6_lwt_lwtunnel(struct lwtunnel_state lwt)
	36	{
	37	return (struct seg6_lwt *)lwt->data;
	38	}
	39
	40	static inline struct seg6_iptunnel_encap *
	41	seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
	42	{
	43	return seg6_lwt_lwtunnel(lwt)->tuninfo;
	44	}
	45
	46	static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
	47	[SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
	48	};
	49
bb4005ba WY	50	static int nla_put_srh(struct sk_buff *skb, int attrtype,
bb4005ba WY	51	struct seg6_iptunnel_encap *tuninfo)
6c8702c6 DL	52	{
	53	struct seg6_iptunnel_encap *data;
	54	struct nlattr *nla;
	55	int len;
	56
	57	len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
	58
	59	nla = nla_reserve(skb, attrtype, len);
	60	if (!nla)
	61	return -EMSGSIZE;
	62
	63	data = nla_data(nla);
	64	memcpy(data, tuninfo, len);
	65
	66	return 0;
	67	}
	68
	69	static void set_tun_src(struct net net, struct net_device dev,
	70	struct in6_addr daddr, struct in6_addr saddr)
	71	{
	72	struct seg6_pernet_data *sdata = seg6_pernet(net);
	73	struct in6_addr *tun_src;
	74
	75	rcu_read_lock();
	76
	77	tun_src = rcu_dereference(sdata->tun_src);
	78
	79	if (!ipv6_addr_any(tun_src)) {
	80	memcpy(saddr, tun_src, sizeof(struct in6_addr));
	81	} else {
	82	ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
	83	saddr);
	84	}
	85
	86	rcu_read_unlock();
	87	}
	88
b5facfdb AA	89	/* Compute flowlabel for outer IPv6 header */
	90	static __be32 seg6_make_flowlabel(struct net net, struct sk_buff skb,
	91	struct ipv6hdr *inner_hdr)
	92	{
	93	int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
	94	__be32 flowlabel = 0;
	95	u32 hash;
	96
	97	if (do_flowlabel > 0) {
	98	hash = skb_get_hash(skb);
3ee593ad	99	hash = rol32(hash, 16);
b5facfdb AA	100	flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
	101	} else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
	102	flowlabel = ip6_flowlabel(inner_hdr);
	103	}
	104	return flowlabel;
	105	}
	106
6c8702c6	107	/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
32d99d0b	108	int seg6_do_srh_encap(struct sk_buff skb, struct ipv6_sr_hdr osrh, int proto)
6c8702c6	109	{
8936ef76 DL	110	struct dst_entry *dst = skb_dst(skb);
8936ef76 DL	111	struct net *net = dev_net(dst->dev);
6c8702c6 DL	112	struct ipv6hdr hdr, inner_hdr;
	113	struct ipv6_sr_hdr *isrh;
	114	int hdrlen, tot_len, err;
b5facfdb	115	__be32 flowlabel;
6c8702c6 DL	116
	117	hdrlen = (osrh->hdrlen + 1) << 3;
	118	tot_len = hdrlen + sizeof(*hdr);
	119
bbb40a0b	120	err = skb_cow_head(skb, tot_len + skb->mac_len);
6c8702c6 DL	121	if (unlikely(err))
	122	return err;
	123
	124	inner_hdr = ipv6_hdr(skb);
6df93462	125	flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
6c8702c6 DL	126
	127	skb_push(skb, tot_len);
	128	skb_reset_network_header(skb);
	129	skb_mac_header_rebuild(skb);
	130	hdr = ipv6_hdr(skb);
	131
	132	/* inherit tc, flowlabel and hlim
	133	* hlim will be decremented in ip6_forward() afterwards and
	134	* decapsulation will overwrite inner hlim with outer hlim
	135	*/
32d99d0b DL	136
	137	if (skb->protocol == htons(ETH_P_IPV6)) {
	138	ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
b5facfdb	139	flowlabel);
32d99d0b DL	140	hdr->hop_limit = inner_hdr->hop_limit;
32d99d0b DL	141	} else {
b5facfdb	142	ip6_flow_hdr(hdr, 0, flowlabel);
32d99d0b	143	hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
ef489749 YK	144
ef489749 YK	145	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
32d99d0b DL	146	}
32d99d0b DL	147
6c8702c6 DL	148	hdr->nexthdr = NEXTHDR_ROUTING;
	149
	150	isrh = (void )hdr + sizeof(hdr);
	151	memcpy(isrh, osrh, hdrlen);
	152
32d99d0b	153	isrh->nexthdr = proto;
6c8702c6 DL	154
6c8702c6 DL	155	hdr->daddr = isrh->segments[isrh->first_segment];
a957fa19	156	set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
6c8702c6	157
9baee834 DL	158	#ifdef CONFIG_IPV6_SEG6_HMAC
	159	if (sr_has_hmac(isrh)) {
	160	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	161	if (unlikely(err))
	162	return err;
	163	}
	164	#endif
	165
6c8702c6 DL	166	skb_postpush_rcsum(skb, hdr, tot_len);
	167
	168	return 0;
	169	}
b04c80d3	170	EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
6c8702c6 DL	171
6c8702c6 DL	172	/* insert an SRH within an IPv6 packet, just after the IPv6 header */
b04c80d3	173	int seg6_do_srh_inline(struct sk_buff skb, struct ipv6_sr_hdr osrh)
6c8702c6 DL	174	{
	175	struct ipv6hdr hdr, oldhdr;
	176	struct ipv6_sr_hdr *isrh;
	177	int hdrlen, err;
	178
	179	hdrlen = (osrh->hdrlen + 1) << 3;
	180
bbb40a0b	181	err = skb_cow_head(skb, hdrlen + skb->mac_len);
6c8702c6 DL	182	if (unlikely(err))
	183	return err;
	184
	185	oldhdr = ipv6_hdr(skb);
	186
	187	skb_pull(skb, sizeof(struct ipv6hdr));
	188	skb_postpull_rcsum(skb, skb_network_header(skb),
	189	sizeof(struct ipv6hdr));
	190
	191	skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
	192	skb_reset_network_header(skb);
	193	skb_mac_header_rebuild(skb);
	194
	195	hdr = ipv6_hdr(skb);
	196
	197	memmove(hdr, oldhdr, sizeof(*hdr));
	198
	199	isrh = (void )hdr + sizeof(hdr);
	200	memcpy(isrh, osrh, hdrlen);
	201
	202	isrh->nexthdr = hdr->nexthdr;
	203	hdr->nexthdr = NEXTHDR_ROUTING;
	204
	205	isrh->segments[0] = hdr->daddr;
	206	hdr->daddr = isrh->segments[isrh->first_segment];
	207
9baee834 DL	208	#ifdef CONFIG_IPV6_SEG6_HMAC
	209	if (sr_has_hmac(isrh)) {
	210	struct net *net = dev_net(skb_dst(skb)->dev);
	211
	212	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	213	if (unlikely(err))
	214	return err;
	215	}
	216	#endif
	217
6c8702c6 DL	218	skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
	219
	220	return 0;
	221	}
b04c80d3	222	EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
6c8702c6 DL	223
	224	static int seg6_do_srh(struct sk_buff *skb)
	225	{
	226	struct dst_entry *dst = skb_dst(skb);
	227	struct seg6_iptunnel_encap *tinfo;
32d99d0b	228	int proto, err = 0;
6c8702c6 DL	229
	230	tinfo = seg6_encap_lwtunnel(dst->lwtstate);
	231
6c8702c6	232	switch (tinfo->mode) {
6c8702c6	233	case SEG6_IPTUN_MODE_INLINE:
32d99d0b DL	234	if (skb->protocol != htons(ETH_P_IPV6))
	235	return -EINVAL;
	236
6c8702c6	237	err = seg6_do_srh_inline(skb, tinfo->srh);
32d99d0b DL	238	if (err)
32d99d0b DL	239	return err;
6c8702c6	240	break;
6c8702c6	241	case SEG6_IPTUN_MODE_ENCAP:
5807b22c DL	242	err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
	243	if (err)
	244	return err;
	245
32d99d0b DL	246	if (skb->protocol == htons(ETH_P_IPV6))
	247	proto = IPPROTO_IPV6;
	248	else if (skb->protocol == htons(ETH_P_IP))
	249	proto = IPPROTO_IPIP;
	250	else
	251	return -EINVAL;
	252
	253	err = seg6_do_srh_encap(skb, tinfo->srh, proto);
	254	if (err)
	255	return err;
	256
5807b22c DL	257	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
5807b22c DL	258	skb_set_inner_protocol(skb, skb->protocol);
38ee7f2d DL	259	skb->protocol = htons(ETH_P_IPV6);
	260	break;
	261	case SEG6_IPTUN_MODE_L2ENCAP:
	262	if (!skb_mac_header_was_set(skb))
	263	return -EINVAL;
	264
	265	if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
	266	return -ENOMEM;
	267
	268	skb_mac_header_rebuild(skb);
	269	skb_push(skb, skb->mac_len);
	270
26776253	271	err = seg6_do_srh_encap(skb, tinfo->srh, IPPROTO_ETHERNET);
38ee7f2d DL	272	if (err)
	273	return err;
	274
32d99d0b	275	skb->protocol = htons(ETH_P_IPV6);
6c8702c6 DL	276	break;
	277	}
	278
6c8702c6 DL	279	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	280	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
	281
6c8702c6 DL	282	return 0;
	283	}
	284
bb4005ba	285	static int seg6_input(struct sk_buff *skb)
6c8702c6	286	{
af4a2209 DL	287	struct dst_entry *orig_dst = skb_dst(skb);
	288	struct dst_entry *dst = NULL;
	289	struct seg6_lwt *slwt;
6c8702c6 DL	290	int err;
	291
	292	err = seg6_do_srh(skb);
	293	if (unlikely(err)) {
	294	kfree_skb(skb);
	295	return err;
	296	}
	297
af4a2209 DL	298	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
af4a2209 DL	299
af4a2209 DL	300	preempt_disable();
	301	dst = dst_cache_get(&slwt->cache);
	302	preempt_enable();
af4a2209	303
6c8702c6	304	skb_dst_drop(skb);
af4a2209 DL	305
	306	if (!dst) {
	307	ip6_route_input(skb);
af4a2209 DL	308	dst = skb_dst(skb);
	309	if (!dst->error) {
	310	preempt_disable();
	311	dst_cache_set_ip6(&slwt->cache, dst,
	312	&ipv6_hdr(skb)->saddr);
	313	preempt_enable();
	314	}
af4a2209 DL	315	} else {
	316	skb_dst_set(skb, dst);
	317	}
6c8702c6	318
af3b5158 DL	319	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	320	if (unlikely(err))
	321	return err;
	322
6c8702c6 DL	323	return dst_input(skb);
	324	}
	325
bb4005ba	326	static int seg6_output(struct net net, struct sock sk, struct sk_buff *skb)
6c8702c6 DL	327	{
	328	struct dst_entry *orig_dst = skb_dst(skb);
	329	struct dst_entry *dst = NULL;
	330	struct seg6_lwt *slwt;
	331	int err = -EINVAL;
	332
	333	err = seg6_do_srh(skb);
	334	if (unlikely(err))
	335	goto drop;
	336
	337	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
	338
fa79581e	339	preempt_disable();
6c8702c6	340	dst = dst_cache_get(&slwt->cache);
fa79581e	341	preempt_enable();
6c8702c6 DL	342
	343	if (unlikely(!dst)) {
	344	struct ipv6hdr *hdr = ipv6_hdr(skb);
	345	struct flowi6 fl6;
	346
1b4e5ad5	347	memset(&fl6, 0, sizeof(fl6));
6c8702c6 DL	348	fl6.daddr = hdr->daddr;
	349	fl6.saddr = hdr->saddr;
	350	fl6.flowlabel = ip6_flowinfo(hdr);
	351	fl6.flowi6_mark = skb->mark;
	352	fl6.flowi6_proto = hdr->nexthdr;
	353
	354	dst = ip6_route_output(net, NULL, &fl6);
	355	if (dst->error) {
	356	err = dst->error;
	357	dst_release(dst);
	358	goto drop;
	359	}
	360
fa79581e	361	preempt_disable();
6c8702c6	362	dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
fa79581e	363	preempt_enable();
6c8702c6 DL	364	}
	365
	366	skb_dst_drop(skb);
	367	skb_dst_set(skb, dst);
	368
af3b5158 DL	369	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	370	if (unlikely(err))
	371	goto drop;
	372
6c8702c6 DL	373	return dst_output(net, sk, skb);
	374	drop:
	375	kfree_skb(skb);
	376	return err;
	377	}
	378
30357d7d	379	static int seg6_build_state(struct nlattr *nla,
6c8702c6	380	unsigned int family, const void *cfg,
9ae28727 DA	381	struct lwtunnel_state **ts,
9ae28727 DA	382	struct netlink_ext_ack *extack)
6c8702c6 DL	383	{
	384	struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
	385	struct seg6_iptunnel_encap *tuninfo;
	386	struct lwtunnel_state *newts;
	387	int tuninfo_len, min_size;
	388	struct seg6_lwt *slwt;
	389	int err;
	390
32d99d0b DL	391	if (family != AF_INET && family != AF_INET6)
	392	return -EINVAL;
	393
8cb08174 JB	394	err = nla_parse_nested_deprecated(tb, SEG6_IPTUNNEL_MAX, nla,
8cb08174 JB	395	seg6_iptunnel_policy, extack);
6c8702c6 DL	396
	397	if (err < 0)
	398	return err;
	399
	400	if (!tb[SEG6_IPTUNNEL_SRH])
	401	return -EINVAL;
	402
	403	tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
	404	tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
	405
	406	/* tuninfo must contain at least the iptunnel encap structure,
	407	* the SRH and one segment
	408	*/
	409	min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
	410	sizeof(struct in6_addr);
	411	if (tuninfo_len < min_size)
	412	return -EINVAL;
	413
	414	switch (tuninfo->mode) {
6c8702c6	415	case SEG6_IPTUN_MODE_INLINE:
32d99d0b DL	416	if (family != AF_INET6)
	417	return -EINVAL;
	418
6c8702c6	419	break;
6c8702c6 DL	420	case SEG6_IPTUN_MODE_ENCAP:
6c8702c6 DL	421	break;
38ee7f2d DL	422	case SEG6_IPTUN_MODE_L2ENCAP:
38ee7f2d DL	423	break;
6c8702c6 DL	424	default:
	425	return -EINVAL;
	426	}
	427
	428	/* verify that SRH is consistent */
	429	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo)))
	430	return -EINVAL;
	431
	432	newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
	433	if (!newts)
	434	return -ENOMEM;
	435
	436	slwt = seg6_lwt_lwtunnel(newts);
	437
191f86ca	438	err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
6c8702c6 DL	439	if (err) {
	440	kfree(newts);
	441	return err;
	442	}
6c8702c6 DL	443
	444	memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
	445
	446	newts->type = LWTUNNEL_ENCAP_SEG6;
38ee7f2d DL	447	newts->flags \|= LWTUNNEL_STATE_INPUT_REDIRECT;
	448
	449	if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
	450	newts->flags \|= LWTUNNEL_STATE_OUTPUT_REDIRECT;
	451
6c8702c6 DL	452	newts->headroom = seg6_lwt_headroom(tuninfo);
	453
	454	*ts = newts;
	455
	456	return 0;
	457	}
	458
6c8702c6 DL	459	static void seg6_destroy_state(struct lwtunnel_state *lwt)
	460	{
	461	dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
	462	}
6c8702c6 DL	463
	464	static int seg6_fill_encap_info(struct sk_buff *skb,
	465	struct lwtunnel_state *lwtstate)
	466	{
	467	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
	468
	469	if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
	470	return -EMSGSIZE;
	471
	472	return 0;
	473	}
	474
	475	static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
	476	{
	477	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
	478
	479	return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
	480	}
	481
	482	static int seg6_encap_cmp(struct lwtunnel_state a, struct lwtunnel_state b)
	483	{
	484	struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
	485	struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
	486	int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
	487
	488	if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
	489	return 1;
	490
	491	return memcmp(a_hdr, b_hdr, len);
	492	}
	493
	494	static const struct lwtunnel_encap_ops seg6_iptun_ops = {
	495	.build_state = seg6_build_state,
6c8702c6	496	.destroy_state = seg6_destroy_state,
6c8702c6 DL	497	.output = seg6_output,
	498	.input = seg6_input,
	499	.fill_encap = seg6_fill_encap_info,
	500	.get_encap_size = seg6_encap_nlsize,
	501	.cmp_encap = seg6_encap_cmp,
88ff7334	502	.owner = THIS_MODULE,
6c8702c6 DL	503	};
	504
	505	int __init seg6_iptunnel_init(void)
	506	{
	507	return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
	508	}
	509
	510	void seg6_iptunnel_exit(void)
	511	{
	512	lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
	513	}