[linux-block.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

static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
{
	int head = 0;

	switch (tuninfo->mode) {
	case SEG6_IPTUN_MODE_INLINE:
		break;
	case SEG6_IPTUN_MODE_ENCAP:
		head = sizeof(struct ipv6hdr);
		break;
	case SEG6_IPTUN_MODE_L2ENCAP:
		return 0;
	}

	return ((tuninfo->srh->hdrlen + 1) << 3) + head;
}

struct seg6_lwt {
	struct dst_cache cache;
	struct seg6_iptunnel_encap tuninfo[];
};

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 net *net, 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), false))
		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	29
88fab21c IRS	30	static size_t seg6_lwt_headroom(struct seg6_iptunnel_encap *tuninfo)
	31	{
	32	int head = 0;
	33
	34	switch (tuninfo->mode) {
	35	case SEG6_IPTUN_MODE_INLINE:
	36	break;
	37	case SEG6_IPTUN_MODE_ENCAP:
	38	head = sizeof(struct ipv6hdr);
	39	break;
	40	case SEG6_IPTUN_MODE_L2ENCAP:
	41	return 0;
	42	}
	43
	44	return ((tuninfo->srh->hdrlen + 1) << 3) + head;
	45	}
	46
6c8702c6	47	struct seg6_lwt {
6c8702c6	48	struct dst_cache cache;
b0c9a2d9	49	struct seg6_iptunnel_encap tuninfo[];
6c8702c6 DL	50	};
	51
	52	static inline struct seg6_lwt seg6_lwt_lwtunnel(struct lwtunnel_state lwt)
	53	{
	54	return (struct seg6_lwt *)lwt->data;
	55	}
	56
	57	static inline struct seg6_iptunnel_encap *
	58	seg6_encap_lwtunnel(struct lwtunnel_state *lwt)
	59	{
	60	return seg6_lwt_lwtunnel(lwt)->tuninfo;
	61	}
	62
	63	static const struct nla_policy seg6_iptunnel_policy[SEG6_IPTUNNEL_MAX + 1] = {
	64	[SEG6_IPTUNNEL_SRH] = { .type = NLA_BINARY },
	65	};
	66
bb4005ba WY	67	static int nla_put_srh(struct sk_buff *skb, int attrtype,
bb4005ba WY	68	struct seg6_iptunnel_encap *tuninfo)
6c8702c6 DL	69	{
	70	struct seg6_iptunnel_encap *data;
	71	struct nlattr *nla;
	72	int len;
	73
	74	len = SEG6_IPTUN_ENCAP_SIZE(tuninfo);
	75
	76	nla = nla_reserve(skb, attrtype, len);
	77	if (!nla)
	78	return -EMSGSIZE;
	79
	80	data = nla_data(nla);
	81	memcpy(data, tuninfo, len);
	82
	83	return 0;
	84	}
	85
	86	static void set_tun_src(struct net net, struct net_device dev,
	87	struct in6_addr daddr, struct in6_addr saddr)
	88	{
	89	struct seg6_pernet_data *sdata = seg6_pernet(net);
	90	struct in6_addr *tun_src;
	91
	92	rcu_read_lock();
	93
	94	tun_src = rcu_dereference(sdata->tun_src);
	95
	96	if (!ipv6_addr_any(tun_src)) {
	97	memcpy(saddr, tun_src, sizeof(struct in6_addr));
	98	} else {
	99	ipv6_dev_get_saddr(net, dev, daddr, IPV6_PREFER_SRC_PUBLIC,
	100	saddr);
	101	}
	102
	103	rcu_read_unlock();
	104	}
	105
b5facfdb AA	106	/* Compute flowlabel for outer IPv6 header */
	107	static __be32 seg6_make_flowlabel(struct net net, struct sk_buff skb,
	108	struct ipv6hdr *inner_hdr)
	109	{
	110	int do_flowlabel = net->ipv6.sysctl.seg6_flowlabel;
	111	__be32 flowlabel = 0;
	112	u32 hash;
	113
	114	if (do_flowlabel > 0) {
	115	hash = skb_get_hash(skb);
3ee593ad	116	hash = rol32(hash, 16);
b5facfdb AA	117	flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
	118	} else if (!do_flowlabel && skb->protocol == htons(ETH_P_IPV6)) {
	119	flowlabel = ip6_flowlabel(inner_hdr);
	120	}
	121	return flowlabel;
	122	}
	123
6c8702c6	124	/* encapsulate an IPv6 packet within an outer IPv6 header with a given SRH */
32d99d0b	125	int seg6_do_srh_encap(struct sk_buff skb, struct ipv6_sr_hdr osrh, int proto)
6c8702c6	126	{
8936ef76 DL	127	struct dst_entry *dst = skb_dst(skb);
8936ef76 DL	128	struct net *net = dev_net(dst->dev);
6c8702c6 DL	129	struct ipv6hdr hdr, inner_hdr;
	130	struct ipv6_sr_hdr *isrh;
	131	int hdrlen, tot_len, err;
b5facfdb	132	__be32 flowlabel;
6c8702c6 DL	133
	134	hdrlen = (osrh->hdrlen + 1) << 3;
	135	tot_len = hdrlen + sizeof(*hdr);
	136
bbb40a0b	137	err = skb_cow_head(skb, tot_len + skb->mac_len);
6c8702c6 DL	138	if (unlikely(err))
	139	return err;
	140
	141	inner_hdr = ipv6_hdr(skb);
6df93462	142	flowlabel = seg6_make_flowlabel(net, skb, inner_hdr);
6c8702c6 DL	143
	144	skb_push(skb, tot_len);
	145	skb_reset_network_header(skb);
	146	skb_mac_header_rebuild(skb);
	147	hdr = ipv6_hdr(skb);
	148
	149	/* inherit tc, flowlabel and hlim
	150	* hlim will be decremented in ip6_forward() afterwards and
	151	* decapsulation will overwrite inner hlim with outer hlim
	152	*/
32d99d0b DL	153
	154	if (skb->protocol == htons(ETH_P_IPV6)) {
	155	ip6_flow_hdr(hdr, ip6_tclass(ip6_flowinfo(inner_hdr)),
b5facfdb	156	flowlabel);
32d99d0b DL	157	hdr->hop_limit = inner_hdr->hop_limit;
32d99d0b DL	158	} else {
b5facfdb	159	ip6_flow_hdr(hdr, 0, flowlabel);
32d99d0b	160	hdr->hop_limit = ip6_dst_hoplimit(skb_dst(skb));
ef489749 YK	161
ef489749 YK	162	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
32d99d0b DL	163	}
32d99d0b DL	164
6c8702c6 DL	165	hdr->nexthdr = NEXTHDR_ROUTING;
	166
	167	isrh = (void )hdr + sizeof(hdr);
	168	memcpy(isrh, osrh, hdrlen);
	169
32d99d0b	170	isrh->nexthdr = proto;
6c8702c6 DL	171
6c8702c6 DL	172	hdr->daddr = isrh->segments[isrh->first_segment];
a957fa19	173	set_tun_src(net, dst->dev, &hdr->daddr, &hdr->saddr);
6c8702c6	174
9baee834 DL	175	#ifdef CONFIG_IPV6_SEG6_HMAC
	176	if (sr_has_hmac(isrh)) {
	177	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	178	if (unlikely(err))
	179	return err;
	180	}
	181	#endif
	182
6c8702c6 DL	183	skb_postpush_rcsum(skb, hdr, tot_len);
	184
	185	return 0;
	186	}
b04c80d3	187	EXPORT_SYMBOL_GPL(seg6_do_srh_encap);
6c8702c6 DL	188
6c8702c6 DL	189	/* insert an SRH within an IPv6 packet, just after the IPv6 header */
b04c80d3	190	int seg6_do_srh_inline(struct sk_buff skb, struct ipv6_sr_hdr osrh)
6c8702c6 DL	191	{
	192	struct ipv6hdr hdr, oldhdr;
	193	struct ipv6_sr_hdr *isrh;
	194	int hdrlen, err;
	195
	196	hdrlen = (osrh->hdrlen + 1) << 3;
	197
bbb40a0b	198	err = skb_cow_head(skb, hdrlen + skb->mac_len);
6c8702c6 DL	199	if (unlikely(err))
	200	return err;
	201
	202	oldhdr = ipv6_hdr(skb);
	203
	204	skb_pull(skb, sizeof(struct ipv6hdr));
	205	skb_postpull_rcsum(skb, skb_network_header(skb),
	206	sizeof(struct ipv6hdr));
	207
	208	skb_push(skb, sizeof(struct ipv6hdr) + hdrlen);
	209	skb_reset_network_header(skb);
	210	skb_mac_header_rebuild(skb);
	211
	212	hdr = ipv6_hdr(skb);
	213
	214	memmove(hdr, oldhdr, sizeof(*hdr));
	215
	216	isrh = (void )hdr + sizeof(hdr);
	217	memcpy(isrh, osrh, hdrlen);
	218
	219	isrh->nexthdr = hdr->nexthdr;
	220	hdr->nexthdr = NEXTHDR_ROUTING;
	221
	222	isrh->segments[0] = hdr->daddr;
	223	hdr->daddr = isrh->segments[isrh->first_segment];
	224
9baee834 DL	225	#ifdef CONFIG_IPV6_SEG6_HMAC
	226	if (sr_has_hmac(isrh)) {
	227	struct net *net = dev_net(skb_dst(skb)->dev);
	228
	229	err = seg6_push_hmac(net, &hdr->saddr, isrh);
	230	if (unlikely(err))
	231	return err;
	232	}
	233	#endif
	234
6c8702c6 DL	235	skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen);
	236
	237	return 0;
	238	}
b04c80d3	239	EXPORT_SYMBOL_GPL(seg6_do_srh_inline);
6c8702c6 DL	240
	241	static int seg6_do_srh(struct sk_buff *skb)
	242	{
	243	struct dst_entry *dst = skb_dst(skb);
	244	struct seg6_iptunnel_encap *tinfo;
32d99d0b	245	int proto, err = 0;
6c8702c6 DL	246
	247	tinfo = seg6_encap_lwtunnel(dst->lwtstate);
	248
6c8702c6	249	switch (tinfo->mode) {
6c8702c6	250	case SEG6_IPTUN_MODE_INLINE:
32d99d0b DL	251	if (skb->protocol != htons(ETH_P_IPV6))
	252	return -EINVAL;
	253
6c8702c6	254	err = seg6_do_srh_inline(skb, tinfo->srh);
32d99d0b DL	255	if (err)
32d99d0b DL	256	return err;
6c8702c6	257	break;
6c8702c6	258	case SEG6_IPTUN_MODE_ENCAP:
5807b22c DL	259	err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
	260	if (err)
	261	return err;
	262
32d99d0b DL	263	if (skb->protocol == htons(ETH_P_IPV6))
	264	proto = IPPROTO_IPV6;
	265	else if (skb->protocol == htons(ETH_P_IP))
	266	proto = IPPROTO_IPIP;
	267	else
	268	return -EINVAL;
	269
	270	err = seg6_do_srh_encap(skb, tinfo->srh, proto);
	271	if (err)
	272	return err;
	273
5807b22c DL	274	skb_set_inner_transport_header(skb, skb_transport_offset(skb));
5807b22c DL	275	skb_set_inner_protocol(skb, skb->protocol);
38ee7f2d DL	276	skb->protocol = htons(ETH_P_IPV6);
	277	break;
	278	case SEG6_IPTUN_MODE_L2ENCAP:
	279	if (!skb_mac_header_was_set(skb))
	280	return -EINVAL;
	281
	282	if (pskb_expand_head(skb, skb->mac_len, 0, GFP_ATOMIC) < 0)
	283	return -ENOMEM;
	284
	285	skb_mac_header_rebuild(skb);
	286	skb_push(skb, skb->mac_len);
	287
26776253	288	err = seg6_do_srh_encap(skb, tinfo->srh, IPPROTO_ETHERNET);
38ee7f2d DL	289	if (err)
	290	return err;
	291
32d99d0b	292	skb->protocol = htons(ETH_P_IPV6);
6c8702c6 DL	293	break;
	294	}
	295
6c8702c6 DL	296	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
	297	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
	298
6c8702c6 DL	299	return 0;
	300	}
	301
bb4005ba	302	static int seg6_input(struct sk_buff *skb)
6c8702c6	303	{
af4a2209 DL	304	struct dst_entry *orig_dst = skb_dst(skb);
	305	struct dst_entry *dst = NULL;
	306	struct seg6_lwt *slwt;
6c8702c6 DL	307	int err;
	308
	309	err = seg6_do_srh(skb);
	310	if (unlikely(err)) {
	311	kfree_skb(skb);
	312	return err;
	313	}
	314
af4a2209 DL	315	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
af4a2209 DL	316
af4a2209 DL	317	preempt_disable();
	318	dst = dst_cache_get(&slwt->cache);
	319	preempt_enable();
af4a2209	320
6c8702c6	321	skb_dst_drop(skb);
af4a2209 DL	322
	323	if (!dst) {
	324	ip6_route_input(skb);
af4a2209 DL	325	dst = skb_dst(skb);
	326	if (!dst->error) {
	327	preempt_disable();
	328	dst_cache_set_ip6(&slwt->cache, dst,
	329	&ipv6_hdr(skb)->saddr);
	330	preempt_enable();
	331	}
af4a2209 DL	332	} else {
	333	skb_dst_set(skb, dst);
	334	}
6c8702c6	335
af3b5158 DL	336	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	337	if (unlikely(err))
	338	return err;
	339
6c8702c6 DL	340	return dst_input(skb);
	341	}
	342
bb4005ba	343	static int seg6_output(struct net net, struct sock sk, struct sk_buff *skb)
6c8702c6 DL	344	{
	345	struct dst_entry *orig_dst = skb_dst(skb);
	346	struct dst_entry *dst = NULL;
	347	struct seg6_lwt *slwt;
	348	int err = -EINVAL;
	349
	350	err = seg6_do_srh(skb);
	351	if (unlikely(err))
	352	goto drop;
	353
	354	slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate);
	355
fa79581e	356	preempt_disable();
6c8702c6	357	dst = dst_cache_get(&slwt->cache);
fa79581e	358	preempt_enable();
6c8702c6 DL	359
	360	if (unlikely(!dst)) {
	361	struct ipv6hdr *hdr = ipv6_hdr(skb);
	362	struct flowi6 fl6;
	363
1b4e5ad5	364	memset(&fl6, 0, sizeof(fl6));
6c8702c6 DL	365	fl6.daddr = hdr->daddr;
	366	fl6.saddr = hdr->saddr;
	367	fl6.flowlabel = ip6_flowinfo(hdr);
	368	fl6.flowi6_mark = skb->mark;
	369	fl6.flowi6_proto = hdr->nexthdr;
	370
	371	dst = ip6_route_output(net, NULL, &fl6);
	372	if (dst->error) {
	373	err = dst->error;
	374	dst_release(dst);
	375	goto drop;
	376	}
	377
fa79581e	378	preempt_disable();
6c8702c6	379	dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr);
fa79581e	380	preempt_enable();
6c8702c6 DL	381	}
	382
	383	skb_dst_drop(skb);
	384	skb_dst_set(skb, dst);
	385
af3b5158 DL	386	err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
	387	if (unlikely(err))
	388	goto drop;
	389
6c8702c6 DL	390	return dst_output(net, sk, skb);
	391	drop:
	392	kfree_skb(skb);
	393	return err;
	394	}
	395
faee6769	396	static int seg6_build_state(struct net net, struct nlattr nla,
6c8702c6	397	unsigned int family, const void *cfg,
9ae28727 DA	398	struct lwtunnel_state **ts,
9ae28727 DA	399	struct netlink_ext_ack *extack)
6c8702c6 DL	400	{
	401	struct nlattr *tb[SEG6_IPTUNNEL_MAX + 1];
	402	struct seg6_iptunnel_encap *tuninfo;
	403	struct lwtunnel_state *newts;
	404	int tuninfo_len, min_size;
	405	struct seg6_lwt *slwt;
	406	int err;
	407
32d99d0b DL	408	if (family != AF_INET && family != AF_INET6)
	409	return -EINVAL;
	410
8cb08174 JB	411	err = nla_parse_nested_deprecated(tb, SEG6_IPTUNNEL_MAX, nla,
8cb08174 JB	412	seg6_iptunnel_policy, extack);
6c8702c6 DL	413
	414	if (err < 0)
	415	return err;
	416
	417	if (!tb[SEG6_IPTUNNEL_SRH])
	418	return -EINVAL;
	419
	420	tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
	421	tuninfo_len = nla_len(tb[SEG6_IPTUNNEL_SRH]);
	422
	423	/* tuninfo must contain at least the iptunnel encap structure,
	424	* the SRH and one segment
	425	*/
	426	min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
	427	sizeof(struct in6_addr);
	428	if (tuninfo_len < min_size)
	429	return -EINVAL;
	430
	431	switch (tuninfo->mode) {
6c8702c6	432	case SEG6_IPTUN_MODE_INLINE:
32d99d0b DL	433	if (family != AF_INET6)
	434	return -EINVAL;
	435
6c8702c6	436	break;
6c8702c6 DL	437	case SEG6_IPTUN_MODE_ENCAP:
6c8702c6 DL	438	break;
38ee7f2d DL	439	case SEG6_IPTUN_MODE_L2ENCAP:
38ee7f2d DL	440	break;
6c8702c6 DL	441	default:
	442	return -EINVAL;
	443	}
	444
	445	/* verify that SRH is consistent */
bb986a50	446	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo), false))
6c8702c6 DL	447	return -EINVAL;
	448
	449	newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
	450	if (!newts)
	451	return -ENOMEM;
	452
	453	slwt = seg6_lwt_lwtunnel(newts);
	454
191f86ca	455	err = dst_cache_init(&slwt->cache, GFP_ATOMIC);
6c8702c6 DL	456	if (err) {
	457	kfree(newts);
	458	return err;
	459	}
6c8702c6 DL	460
	461	memcpy(&slwt->tuninfo, tuninfo, tuninfo_len);
	462
	463	newts->type = LWTUNNEL_ENCAP_SEG6;
38ee7f2d DL	464	newts->flags \|= LWTUNNEL_STATE_INPUT_REDIRECT;
	465
	466	if (tuninfo->mode != SEG6_IPTUN_MODE_L2ENCAP)
	467	newts->flags \|= LWTUNNEL_STATE_OUTPUT_REDIRECT;
	468
6c8702c6 DL	469	newts->headroom = seg6_lwt_headroom(tuninfo);
	470
	471	*ts = newts;
	472
	473	return 0;
	474	}
	475
6c8702c6 DL	476	static void seg6_destroy_state(struct lwtunnel_state *lwt)
	477	{
	478	dst_cache_destroy(&seg6_lwt_lwtunnel(lwt)->cache);
	479	}
6c8702c6 DL	480
	481	static int seg6_fill_encap_info(struct sk_buff *skb,
	482	struct lwtunnel_state *lwtstate)
	483	{
	484	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
	485
	486	if (nla_put_srh(skb, SEG6_IPTUNNEL_SRH, tuninfo))
	487	return -EMSGSIZE;
	488
	489	return 0;
	490	}
	491
	492	static int seg6_encap_nlsize(struct lwtunnel_state *lwtstate)
	493	{
	494	struct seg6_iptunnel_encap *tuninfo = seg6_encap_lwtunnel(lwtstate);
	495
	496	return nla_total_size(SEG6_IPTUN_ENCAP_SIZE(tuninfo));
	497	}
	498
	499	static int seg6_encap_cmp(struct lwtunnel_state a, struct lwtunnel_state b)
	500	{
	501	struct seg6_iptunnel_encap *a_hdr = seg6_encap_lwtunnel(a);
	502	struct seg6_iptunnel_encap *b_hdr = seg6_encap_lwtunnel(b);
	503	int len = SEG6_IPTUN_ENCAP_SIZE(a_hdr);
	504
	505	if (len != SEG6_IPTUN_ENCAP_SIZE(b_hdr))
	506	return 1;
	507
	508	return memcmp(a_hdr, b_hdr, len);
	509	}
	510
	511	static const struct lwtunnel_encap_ops seg6_iptun_ops = {
	512	.build_state = seg6_build_state,
6c8702c6	513	.destroy_state = seg6_destroy_state,
6c8702c6 DL	514	.output = seg6_output,
	515	.input = seg6_input,
	516	.fill_encap = seg6_fill_encap_info,
	517	.get_encap_size = seg6_encap_nlsize,
	518	.cmp_encap = seg6_encap_cmp,
88ff7334	519	.owner = THIS_MODULE,
6c8702c6 DL	520	};
	521
	522	int __init seg6_iptunnel_init(void)
	523	{
	524	return lwtunnel_encap_add_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
	525	}
	526
	527	void seg6_iptunnel_exit(void)
	528	{
	529	lwtunnel_encap_del_ops(&seg6_iptun_ops, LWTUNNEL_ENCAP_SEG6);
	530	}