Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2310 insertions, 0 deletions

diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
new file mode 100644
index 000000000..8370726ae
--- /dev/null
+++ b/net/ipv6/seg6_local.c
@@ -0,0 +1,2310 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  SR-IPv6 implementation
+ *
+ *  Authors:
+ *  David Lebrun <david.lebrun@uclouvain.be>
+ *  eBPF support: Mathieu Xhonneux <m.xhonneux@gmail.com>
+ */
+
+#include <linux/filter.h>
+#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_local.h>
+#include <net/addrconf.h>
+#include <net/ip6_route.h>
+#include <net/dst_cache.h>
+#include <net/ip_tunnels.h>
+#ifdef CONFIG_IPV6_SEG6_HMAC
+#include <net/seg6_hmac.h>
+#endif
+#include <net/seg6_local.h>
+#include <linux/etherdevice.h>
+#include <linux/bpf.h>
+#include <linux/netfilter.h>
+
+#define SEG6_F_ATTR(i)		BIT(i)
+
+struct seg6_local_lwt;
+
+/* callbacks used for customizing the creation and destruction of a behavior */
+struct seg6_local_lwtunnel_ops {
+	int (*build_state)(struct seg6_local_lwt *slwt, const void *cfg,
+			   struct netlink_ext_ack *extack);
+	void (*destroy_state)(struct seg6_local_lwt *slwt);
+};
+
+struct seg6_action_desc {
+	int action;
+	unsigned long attrs;
+
+	/* The optattrs field is used for specifying all the optional
+	 * attributes supported by a specific behavior.
+	 * It means that if one of these attributes is not provided in the
+	 * netlink message during the behavior creation, no errors will be
+	 * returned to the userspace.
+	 *
+	 * Each attribute can be only of two types (mutually exclusive):
+	 * 1) required or 2) optional.
+	 * Every user MUST obey to this rule! If you set an attribute as
+	 * required the same attribute CANNOT be set as optional and vice
+	 * versa.
+	 */
+	unsigned long optattrs;
+
+	int (*input)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
+	int static_headroom;
+
+	struct seg6_local_lwtunnel_ops slwt_ops;
+};
+
+struct bpf_lwt_prog {
+	struct bpf_prog *prog;
+	char *name;
+};
+
+/* default length values (expressed in bits) for both Locator-Block and
+ * Locator-Node Function.
+ *
+ * Both SEG6_LOCAL_LCBLOCK_DBITS and SEG6_LOCAL_LCNODE_FN_DBITS *must* be:
+ *    i) greater than 0;
+ *   ii) evenly divisible by 8. In other terms, the lengths of the
+ *	 Locator-Block and Locator-Node Function must be byte-aligned (we can
+ *	 relax this constraint in the future if really needed).
+ *
+ * Moreover, a third condition must hold:
+ *  iii) SEG6_LOCAL_LCBLOCK_DBITS + SEG6_LOCAL_LCNODE_FN_DBITS <= 128.
+ *
+ * The correctness of SEG6_LOCAL_LCBLOCK_DBITS and SEG6_LOCAL_LCNODE_FN_DBITS
+ * values are checked during the kernel compilation. If the compilation stops,
+ * check the value of these parameters to see if they meet conditions (i), (ii)
+ * and (iii).
+ */
+#define SEG6_LOCAL_LCBLOCK_DBITS	32
+#define SEG6_LOCAL_LCNODE_FN_DBITS	16
+
+/* The following next_csid_chk_{cntr,lcblock,lcblock_fn}_bits macros can be
+ * used directly to check whether the lengths (in bits) of Locator-Block and
+ * Locator-Node Function are valid according to (i), (ii), (iii).
+ */
+#define next_csid_chk_cntr_bits(blen, flen)		\
+	((blen) + (flen) > 128)
+
+#define next_csid_chk_lcblock_bits(blen)		\
+({							\
+	typeof(blen) __tmp = blen;			\
+	(!__tmp || __tmp > 120 || (__tmp & 0x07));	\
+})
+
+#define next_csid_chk_lcnode_fn_bits(flen)		\
+	next_csid_chk_lcblock_bits(flen)
+
+/* Supported Flavor operations are reported in this bitmask */
+#define SEG6_LOCAL_FLV_SUPP_OPS	(BIT(SEG6_LOCAL_FLV_OP_NEXT_CSID))
+
+struct seg6_flavors_info {
+	/* Flavor operations */
+	__u32 flv_ops;
+
+	/* Locator-Block length, expressed in bits */
+	__u8 lcblock_bits;
+	/* Locator-Node Function length, expressed in bits*/
+	__u8 lcnode_func_bits;
+};
+
+enum seg6_end_dt_mode {
+	DT_INVALID_MODE	= -EINVAL,
+	DT_LEGACY_MODE	= 0,
+	DT_VRF_MODE	= 1,
+};
+
+struct seg6_end_dt_info {
+	enum seg6_end_dt_mode mode;
+
+	struct net *net;
+	/* VRF device associated to the routing table used by the SRv6
+	 * End.DT4/DT6 behavior for routing IPv4/IPv6 packets.
+	 */
+	int vrf_ifindex;
+	int vrf_table;
+
+	/* tunneled packet family (IPv4 or IPv6).
+	 * Protocol and header length are inferred from family.
+	 */
+	u16 family;
+};
+
+struct pcpu_seg6_local_counters {
+	u64_stats_t packets;
+	u64_stats_t bytes;
+	u64_stats_t errors;
+
+	struct u64_stats_sync syncp;
+};
+
+/* This struct groups all the SRv6 Behavior counters supported so far.
+ *
+ * put_nla_counters() makes use of this data structure to collect all counter
+ * values after the per-CPU counter evaluation has been performed.
+ * Finally, each counter value (in seg6_local_counters) is stored in the
+ * corresponding netlink attribute and sent to user space.
+ *
+ * NB: we don't want to expose this structure to user space!
+ */
+struct seg6_local_counters {
+	__u64 packets;
+	__u64 bytes;
+	__u64 errors;
+};
+
+#define seg6_local_alloc_pcpu_counters(__gfp)				\
+	__netdev_alloc_pcpu_stats(struct pcpu_seg6_local_counters,	\
+				  ((__gfp) | __GFP_ZERO))
+
+#define SEG6_F_LOCAL_COUNTERS	SEG6_F_ATTR(SEG6_LOCAL_COUNTERS)
+
+struct seg6_local_lwt {
+	int action;
+	struct ipv6_sr_hdr *srh;
+	int table;
+	struct in_addr nh4;
+	struct in6_addr nh6;
+	int iif;
+	int oif;
+	struct bpf_lwt_prog bpf;
+#ifdef CONFIG_NET_L3_MASTER_DEV
+	struct seg6_end_dt_info dt_info;
+#endif
+	struct seg6_flavors_info flv_info;
+
+	struct pcpu_seg6_local_counters __percpu *pcpu_counters;
+
+	int headroom;
+	struct seg6_action_desc *desc;
+	/* unlike the required attrs, we have to track the optional attributes
+	 * that have been effectively parsed.
+	 */
+	unsigned long parsed_optattrs;
+};
+
+static struct seg6_local_lwt *seg6_local_lwtunnel(struct lwtunnel_state *lwt)
+{
+	return (struct seg6_local_lwt *)lwt->data;
+}
+
+static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb)
+{
+	struct ipv6_sr_hdr *srh;
+
+	srh = seg6_get_srh(skb, IP6_FH_F_SKIP_RH);
+	if (!srh)
+		return NULL;
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+	if (!seg6_hmac_validate_skb(skb))
+		return NULL;
+#endif
+
+	return srh;
+}
+
+static bool decap_and_validate(struct sk_buff *skb, int proto)
+{
+	struct ipv6_sr_hdr *srh;
+	unsigned int off = 0;
+
+	srh = seg6_get_srh(skb, 0);
+	if (srh && srh->segments_left > 0)
+		return false;
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+	if (srh && !seg6_hmac_validate_skb(skb))
+		return false;
+#endif
+
+	if (ipv6_find_hdr(skb, &off, proto, NULL, NULL) < 0)
+		return false;
+
+	if (!pskb_pull(skb, off))
+		return false;
+
+	skb_postpull_rcsum(skb, skb_network_header(skb), off);
+
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+	if (iptunnel_pull_offloads(skb))
+		return false;
+
+	return true;
+}
+
+static void advance_nextseg(struct ipv6_sr_hdr *srh, struct in6_addr *daddr)
+{
+	struct in6_addr *addr;
+
+	srh->segments_left--;
+	addr = srh->segments + srh->segments_left;
+	*daddr = *addr;
+}
+
+static int
+seg6_lookup_any_nexthop(struct sk_buff *skb, struct in6_addr *nhaddr,
+			u32 tbl_id, bool local_delivery)
+{
+	struct net *net = dev_net(skb->dev);
+	struct ipv6hdr *hdr = ipv6_hdr(skb);
+	int flags = RT6_LOOKUP_F_HAS_SADDR;
+	struct dst_entry *dst = NULL;
+	struct rt6_info *rt;
+	struct flowi6 fl6;
+	int dev_flags = 0;
+
+	memset(&fl6, 0, sizeof(fl6));
+	fl6.flowi6_iif = skb->dev->ifindex;
+	fl6.daddr = nhaddr ? *nhaddr : hdr->daddr;
+	fl6.saddr = hdr->saddr;
+	fl6.flowlabel = ip6_flowinfo(hdr);
+	fl6.flowi6_mark = skb->mark;
+	fl6.flowi6_proto = hdr->nexthdr;
+
+	if (nhaddr)
+		fl6.flowi6_flags = FLOWI_FLAG_KNOWN_NH;
+
+	if (!tbl_id) {
+		dst = ip6_route_input_lookup(net, skb->dev, &fl6, skb, flags);
+	} else {
+		struct fib6_table *table;
+
+		table = fib6_get_table(net, tbl_id);
+		if (!table)
+			goto out;
+
+		rt = ip6_pol_route(net, table, 0, &fl6, skb, flags);
+		dst = &rt->dst;
+	}
+
+	/* we want to discard traffic destined for local packet processing,
+	 * if @local_delivery is set to false.
+	 */
+	if (!local_delivery)
+		dev_flags |= IFF_LOOPBACK;
+
+	if (dst && (dst->dev->flags & dev_flags) && !dst->error) {
+		dst_release(dst);
+		dst = NULL;
+	}
+
+out:
+	if (!dst) {
+		rt = net->ipv6.ip6_blk_hole_entry;
+		dst = &rt->dst;
+		dst_hold(dst);
+	}
+
+	skb_dst_drop(skb);
+	skb_dst_set(skb, dst);
+	return dst->error;
+}
+
+int seg6_lookup_nexthop(struct sk_buff *skb,
+			struct in6_addr *nhaddr, u32 tbl_id)
+{
+	return seg6_lookup_any_nexthop(skb, nhaddr, tbl_id, false);
+}
+
+static __u8 seg6_flv_lcblock_octects(const struct seg6_flavors_info *finfo)
+{
+	return finfo->lcblock_bits >> 3;
+}
+
+static __u8 seg6_flv_lcnode_func_octects(const struct seg6_flavors_info *finfo)
+{
+	return finfo->lcnode_func_bits >> 3;
+}
+
+static bool seg6_next_csid_is_arg_zero(const struct in6_addr *addr,
+				       const struct seg6_flavors_info *finfo)
+{
+	__u8 fnc_octects = seg6_flv_lcnode_func_octects(finfo);
+	__u8 blk_octects = seg6_flv_lcblock_octects(finfo);
+	__u8 arg_octects;
+	int i;
+
+	arg_octects = 16 - blk_octects - fnc_octects;
+	for (i = 0; i < arg_octects; ++i) {
+		if (addr->s6_addr[blk_octects + fnc_octects + i] != 0x00)
+			return false;
+	}
+
+	return true;
+}
+
+/* assume that DA.Argument length > 0 */
+static void seg6_next_csid_advance_arg(struct in6_addr *addr,
+				       const struct seg6_flavors_info *finfo)
+{
+	__u8 fnc_octects = seg6_flv_lcnode_func_octects(finfo);
+	__u8 blk_octects = seg6_flv_lcblock_octects(finfo);
+
+	/* advance DA.Argument */
+	memmove(&addr->s6_addr[blk_octects],
+		&addr->s6_addr[blk_octects + fnc_octects],
+		16 - blk_octects - fnc_octects);
+
+	memset(&addr->s6_addr[16 - fnc_octects], 0x00, fnc_octects);
+}
+
+static int input_action_end_core(struct sk_buff *skb,
+				 struct seg6_local_lwt *slwt)
+{
+	struct ipv6_sr_hdr *srh;
+
+	srh = get_and_validate_srh(skb);
+	if (!srh)
+		goto drop;
+
+	advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
+
+	seg6_lookup_nexthop(skb, NULL, 0);
+
+	return dst_input(skb);
+
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static int end_next_csid_core(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	const struct seg6_flavors_info *finfo = &slwt->flv_info;
+	struct in6_addr *daddr = &ipv6_hdr(skb)->daddr;
+
+	if (seg6_next_csid_is_arg_zero(daddr, finfo))
+		return input_action_end_core(skb, slwt);
+
+	/* update DA */
+	seg6_next_csid_advance_arg(daddr, finfo);
+
+	seg6_lookup_nexthop(skb, NULL, 0);
+
+	return dst_input(skb);
+}
+
+static bool seg6_next_csid_enabled(__u32 fops)
+{
+	return fops & BIT(SEG6_LOCAL_FLV_OP_NEXT_CSID);
+}
+
+/* regular endpoint function */
+static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	const struct seg6_flavors_info *finfo = &slwt->flv_info;
+
+	if (seg6_next_csid_enabled(finfo->flv_ops))
+		return end_next_csid_core(skb, slwt);
+
+	return input_action_end_core(skb, slwt);
+}
+
+/* regular endpoint, and forward to specified nexthop */
+static int input_action_end_x(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct ipv6_sr_hdr *srh;
+
+	srh = get_and_validate_srh(skb);
+	if (!srh)
+		goto drop;
+
+	advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
+
+	seg6_lookup_nexthop(skb, &slwt->nh6, 0);
+
+	return dst_input(skb);
+
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static int input_action_end_t(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct ipv6_sr_hdr *srh;
+
+	srh = get_and_validate_srh(skb);
+	if (!srh)
+		goto drop;
+
+	advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
+
+	seg6_lookup_nexthop(skb, NULL, slwt->table);
+
+	return dst_input(skb);
+
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+/* decapsulate and forward inner L2 frame on specified interface */
+static int input_action_end_dx2(struct sk_buff *skb,
+				struct seg6_local_lwt *slwt)
+{
+	struct net *net = dev_net(skb->dev);
+	struct net_device *odev;
+	struct ethhdr *eth;
+
+	if (!decap_and_validate(skb, IPPROTO_ETHERNET))
+		goto drop;
+
+	if (!pskb_may_pull(skb, ETH_HLEN))
+		goto drop;
+
+	skb_reset_mac_header(skb);
+	eth = (struct ethhdr *)skb->data;
+
+	/* To determine the frame's protocol, we assume it is 802.3. This avoids
+	 * a call to eth_type_trans(), which is not really relevant for our
+	 * use case.
+	 */
+	if (!eth_proto_is_802_3(eth->h_proto))
+		goto drop;
+
+	odev = dev_get_by_index_rcu(net, slwt->oif);
+	if (!odev)
+		goto drop;
+
+	/* As we accept Ethernet frames, make sure the egress device is of
+	 * the correct type.
+	 */
+	if (odev->type != ARPHRD_ETHER)
+		goto drop;
+
+	if (!(odev->flags & IFF_UP) || !netif_carrier_ok(odev))
+		goto drop;
+
+	skb_orphan(skb);
+
+	if (skb_warn_if_lro(skb))
+		goto drop;
+
+	skb_forward_csum(skb);
+
+	if (skb->len - ETH_HLEN > odev->mtu)
+		goto drop;
+
+	skb->dev = odev;
+	skb->protocol = eth->h_proto;
+
+	return dev_queue_xmit(skb);
+
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static int input_action_end_dx6_finish(struct net *net, struct sock *sk,
+				       struct sk_buff *skb)
+{
+	struct dst_entry *orig_dst = skb_dst(skb);
+	struct in6_addr *nhaddr = NULL;
+	struct seg6_local_lwt *slwt;
+
+	slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
+
+	/* The inner packet is not associated to any local interface,
+	 * so we do not call netif_rx().
+	 *
+	 * If slwt->nh6 is set to ::, then lookup the nexthop for the
+	 * inner packet's DA. Otherwise, use the specified nexthop.
+	 */
+	if (!ipv6_addr_any(&slwt->nh6))
+		nhaddr = &slwt->nh6;
+
+	seg6_lookup_nexthop(skb, nhaddr, 0);
+
+	return dst_input(skb);
+}
+
+/* decapsulate and forward to specified nexthop */
+static int input_action_end_dx6(struct sk_buff *skb,
+				struct seg6_local_lwt *slwt)
+{
+	/* this function accepts IPv6 encapsulated packets, with either
+	 * an SRH with SL=0, or no SRH.
+	 */
+
+	if (!decap_and_validate(skb, IPPROTO_IPV6))
+		goto drop;
+
+	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+		goto drop;
+
+	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+	nf_reset_ct(skb);
+
+	if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+		return NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
+			       dev_net(skb->dev), NULL, skb, NULL,
+			       skb_dst(skb)->dev, input_action_end_dx6_finish);
+
+	return input_action_end_dx6_finish(dev_net(skb->dev), NULL, skb);
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static int input_action_end_dx4_finish(struct net *net, struct sock *sk,
+				       struct sk_buff *skb)
+{
+	struct dst_entry *orig_dst = skb_dst(skb);
+	struct seg6_local_lwt *slwt;
+	struct iphdr *iph;
+	__be32 nhaddr;
+	int err;
+
+	slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
+
+	iph = ip_hdr(skb);
+
+	nhaddr = slwt->nh4.s_addr ?: iph->daddr;
+
+	skb_dst_drop(skb);
+
+	err = ip_route_input(skb, nhaddr, iph->saddr, 0, skb->dev);
+	if (err) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
+	return dst_input(skb);
+}
+
+static int input_action_end_dx4(struct sk_buff *skb,
+				struct seg6_local_lwt *slwt)
+{
+	if (!decap_and_validate(skb, IPPROTO_IPIP))
+		goto drop;
+
+	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+		goto drop;
+
+	skb->protocol = htons(ETH_P_IP);
+	skb_set_transport_header(skb, sizeof(struct iphdr));
+	nf_reset_ct(skb);
+
+	if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+		return NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
+			       dev_net(skb->dev), NULL, skb, NULL,
+			       skb_dst(skb)->dev, input_action_end_dx4_finish);
+
+	return input_action_end_dx4_finish(dev_net(skb->dev), NULL, skb);
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+#ifdef CONFIG_NET_L3_MASTER_DEV
+static struct net *fib6_config_get_net(const struct fib6_config *fib6_cfg)
+{
+	const struct nl_info *nli = &fib6_cfg->fc_nlinfo;
+
+	return nli->nl_net;
+}
+
+static int __seg6_end_dt_vrf_build(struct seg6_local_lwt *slwt, const void *cfg,
+				   u16 family, struct netlink_ext_ack *extack)
+{
+	struct seg6_end_dt_info *info = &slwt->dt_info;
+	int vrf_ifindex;
+	struct net *net;
+
+	net = fib6_config_get_net(cfg);
+
+	/* note that vrf_table was already set by parse_nla_vrftable() */
+	vrf_ifindex = l3mdev_ifindex_lookup_by_table_id(L3MDEV_TYPE_VRF, net,
+							info->vrf_table);
+	if (vrf_ifindex < 0) {
+		if (vrf_ifindex == -EPERM) {
+			NL_SET_ERR_MSG(extack,
+				       "Strict mode for VRF is disabled");
+		} else if (vrf_ifindex == -ENODEV) {
+			NL_SET_ERR_MSG(extack,
+				       "Table has no associated VRF device");
+		} else {
+			pr_debug("seg6local: SRv6 End.DT* creation error=%d\n",
+				 vrf_ifindex);
+		}
+
+		return vrf_ifindex;
+	}
+
+	info->net = net;
+	info->vrf_ifindex = vrf_ifindex;
+
+	info->family = family;
+	info->mode = DT_VRF_MODE;
+
+	return 0;
+}
+
+/* The SRv6 End.DT4/DT6 behavior extracts the inner (IPv4/IPv6) packet and
+ * routes the IPv4/IPv6 packet by looking at the configured routing table.
+ *
+ * In the SRv6 End.DT4/DT6 use case, we can receive traffic (IPv6+Segment
+ * Routing Header packets) from several interfaces and the outer IPv6
+ * destination address (DA) is used for retrieving the specific instance of the
+ * End.DT4/DT6 behavior that should process the packets.
+ *
+ * However, the inner IPv4/IPv6 packet is not really bound to any receiving
+ * interface and thus the End.DT4/DT6 sets the VRF (associated with the
+ * corresponding routing table) as the *receiving* interface.
+ * In other words, the End.DT4/DT6 processes a packet as if it has been received
+ * directly by the VRF (and not by one of its slave devices, if any).
+ * In this way, the VRF interface is used for routing the IPv4/IPv6 packet in
+ * according to the routing table configured by the End.DT4/DT6 instance.
+ *
+ * This design allows you to get some interesting features like:
+ *  1) the statistics on rx packets;
+ *  2) the possibility to install a packet sniffer on the receiving interface
+ *     (the VRF one) for looking at the incoming packets;
+ *  3) the possibility to leverage the netfilter prerouting hook for the inner
+ *     IPv4 packet.
+ *
+ * This function returns:
+ *  - the sk_buff* when the VRF rcv handler has processed the packet correctly;
+ *  - NULL when the skb is consumed by the VRF rcv handler;
+ *  - a pointer which encodes a negative error number in case of error.
+ *    Note that in this case, the function takes care of freeing the skb.
+ */
+static struct sk_buff *end_dt_vrf_rcv(struct sk_buff *skb, u16 family,
+				      struct net_device *dev)
+{
+	/* based on l3mdev_ip_rcv; we are only interested in the master */
+	if (unlikely(!netif_is_l3_master(dev) && !netif_has_l3_rx_handler(dev)))
+		goto drop;
+
+	if (unlikely(!dev->l3mdev_ops->l3mdev_l3_rcv))
+		goto drop;
+
+	/* the decap packet IPv4/IPv6 does not come with any mac header info.
+	 * We must unset the mac header to allow the VRF device to rebuild it,
+	 * just in case there is a sniffer attached on the device.
+	 */
+	skb_unset_mac_header(skb);
+
+	skb = dev->l3mdev_ops->l3mdev_l3_rcv(dev, skb, family);
+	if (!skb)
+		/* the skb buffer was consumed by the handler */
+		return NULL;
+
+	/* when a packet is received by a VRF or by one of its slaves, the
+	 * master device reference is set into the skb.
+	 */
+	if (unlikely(skb->dev != dev || skb->skb_iif != dev->ifindex))
+		goto drop;
+
+	return skb;
+
+drop:
+	kfree_skb(skb);
+	return ERR_PTR(-EINVAL);
+}
+
+static struct net_device *end_dt_get_vrf_rcu(struct sk_buff *skb,
+					     struct seg6_end_dt_info *info)
+{
+	int vrf_ifindex = info->vrf_ifindex;
+	struct net *net = info->net;
+
+	if (unlikely(vrf_ifindex < 0))
+		goto error;
+
+	if (unlikely(!net_eq(dev_net(skb->dev), net)))
+		goto error;
+
+	return dev_get_by_index_rcu(net, vrf_ifindex);
+
+error:
+	return NULL;
+}
+
+static struct sk_buff *end_dt_vrf_core(struct sk_buff *skb,
+				       struct seg6_local_lwt *slwt, u16 family)
+{
+	struct seg6_end_dt_info *info = &slwt->dt_info;
+	struct net_device *vrf;
+	__be16 protocol;
+	int hdrlen;
+
+	vrf = end_dt_get_vrf_rcu(skb, info);
+	if (unlikely(!vrf))
+		goto drop;
+
+	switch (family) {
+	case AF_INET:
+		protocol = htons(ETH_P_IP);
+		hdrlen = sizeof(struct iphdr);
+		break;
+	case AF_INET6:
+		protocol = htons(ETH_P_IPV6);
+		hdrlen = sizeof(struct ipv6hdr);
+		break;
+	case AF_UNSPEC:
+		fallthrough;
+	default:
+		goto drop;
+	}
+
+	if (unlikely(info->family != AF_UNSPEC && info->family != family)) {
+		pr_warn_once("seg6local: SRv6 End.DT* family mismatch");
+		goto drop;
+	}
+
+	skb->protocol = protocol;
+
+	skb_dst_drop(skb);
+
+	skb_set_transport_header(skb, hdrlen);
+	nf_reset_ct(skb);
+
+	return end_dt_vrf_rcv(skb, family, vrf);
+
+drop:
+	kfree_skb(skb);
+	return ERR_PTR(-EINVAL);
+}
+
+static int input_action_end_dt4(struct sk_buff *skb,
+				struct seg6_local_lwt *slwt)
+{
+	struct iphdr *iph;
+	int err;
+
+	if (!decap_and_validate(skb, IPPROTO_IPIP))
+		goto drop;
+
+	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+		goto drop;
+
+	skb = end_dt_vrf_core(skb, slwt, AF_INET);
+	if (!skb)
+		/* packet has been processed and consumed by the VRF */
+		return 0;
+
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	iph = ip_hdr(skb);
+
+	err = ip_route_input(skb, iph->daddr, iph->saddr, 0, skb->dev);
+	if (unlikely(err))
+		goto drop;
+
+	return dst_input(skb);
+
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static int seg6_end_dt4_build(struct seg6_local_lwt *slwt, const void *cfg,
+			      struct netlink_ext_ack *extack)
+{
+	return __seg6_end_dt_vrf_build(slwt, cfg, AF_INET, extack);
+}
+
+static enum
+seg6_end_dt_mode seg6_end_dt6_parse_mode(struct seg6_local_lwt *slwt)
+{
+	unsigned long parsed_optattrs = slwt->parsed_optattrs;
+	bool legacy, vrfmode;
+
+	legacy	= !!(parsed_optattrs & SEG6_F_ATTR(SEG6_LOCAL_TABLE));
+	vrfmode	= !!(parsed_optattrs & SEG6_F_ATTR(SEG6_LOCAL_VRFTABLE));
+
+	if (!(legacy ^ vrfmode))
+		/* both are absent or present: invalid DT6 mode */
+		return DT_INVALID_MODE;
+
+	return legacy ? DT_LEGACY_MODE : DT_VRF_MODE;
+}
+
+static enum seg6_end_dt_mode seg6_end_dt6_get_mode(struct seg6_local_lwt *slwt)
+{
+	struct seg6_end_dt_info *info = &slwt->dt_info;
+
+	return info->mode;
+}
+
+static int seg6_end_dt6_build(struct seg6_local_lwt *slwt, const void *cfg,
+			      struct netlink_ext_ack *extack)
+{
+	enum seg6_end_dt_mode mode = seg6_end_dt6_parse_mode(slwt);
+	struct seg6_end_dt_info *info = &slwt->dt_info;
+
+	switch (mode) {
+	case DT_LEGACY_MODE:
+		info->mode = DT_LEGACY_MODE;
+		return 0;
+	case DT_VRF_MODE:
+		return __seg6_end_dt_vrf_build(slwt, cfg, AF_INET6, extack);
+	default:
+		NL_SET_ERR_MSG(extack, "table or vrftable must be specified");
+		return -EINVAL;
+	}
+}
+#endif
+
+static int input_action_end_dt6(struct sk_buff *skb,
+				struct seg6_local_lwt *slwt)
+{
+	if (!decap_and_validate(skb, IPPROTO_IPV6))
+		goto drop;
+
+	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+		goto drop;
+
+#ifdef CONFIG_NET_L3_MASTER_DEV
+	if (seg6_end_dt6_get_mode(slwt) == DT_LEGACY_MODE)
+		goto legacy_mode;
+
+	/* DT6_VRF_MODE */
+	skb = end_dt_vrf_core(skb, slwt, AF_INET6);
+	if (!skb)
+		/* packet has been processed and consumed by the VRF */
+		return 0;
+
+	if (IS_ERR(skb))
+		return PTR_ERR(skb);
+
+	/* note: this time we do not need to specify the table because the VRF
+	 * takes care of selecting the correct table.
+	 */
+	seg6_lookup_any_nexthop(skb, NULL, 0, true);
+
+	return dst_input(skb);
+
+legacy_mode:
+#endif
+	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+
+	seg6_lookup_any_nexthop(skb, NULL, slwt->table, true);
+
+	return dst_input(skb);
+
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+#ifdef CONFIG_NET_L3_MASTER_DEV
+static int seg6_end_dt46_build(struct seg6_local_lwt *slwt, const void *cfg,
+			       struct netlink_ext_ack *extack)
+{
+	return __seg6_end_dt_vrf_build(slwt, cfg, AF_UNSPEC, extack);
+}
+
+static int input_action_end_dt46(struct sk_buff *skb,
+				 struct seg6_local_lwt *slwt)
+{
+	unsigned int off = 0;
+	int nexthdr;
+
+	nexthdr = ipv6_find_hdr(skb, &off, -1, NULL, NULL);
+	if (unlikely(nexthdr < 0))
+		goto drop;
+
+	switch (nexthdr) {
+	case IPPROTO_IPIP:
+		return input_action_end_dt4(skb, slwt);
+	case IPPROTO_IPV6:
+		return input_action_end_dt6(skb, slwt);
+	}
+
+drop:
+	kfree_skb(skb);
+	return -EINVAL;
+}
+#endif
+
+/* push an SRH on top of the current one */
+static int input_action_end_b6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct ipv6_sr_hdr *srh;
+	int err = -EINVAL;
+
+	srh = get_and_validate_srh(skb);
+	if (!srh)
+		goto drop;
+
+	err = seg6_do_srh_inline(skb, slwt->srh);
+	if (err)
+		goto drop;
+
+	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+
+	seg6_lookup_nexthop(skb, NULL, 0);
+
+	return dst_input(skb);
+
+drop:
+	kfree_skb(skb);
+	return err;
+}
+
+/* encapsulate within an outer IPv6 header and a specified SRH */
+static int input_action_end_b6_encap(struct sk_buff *skb,
+				     struct seg6_local_lwt *slwt)
+{
+	struct ipv6_sr_hdr *srh;
+	int err = -EINVAL;
+
+	srh = get_and_validate_srh(skb);
+	if (!srh)
+		goto drop;
+
+	advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
+
+	skb_reset_inner_headers(skb);
+	skb->encapsulation = 1;
+
+	err = seg6_do_srh_encap(skb, slwt->srh, IPPROTO_IPV6);
+	if (err)
+		goto drop;
+
+	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+
+	seg6_lookup_nexthop(skb, NULL, 0);
+
+	return dst_input(skb);
+
+drop:
+	kfree_skb(skb);
+	return err;
+}
+
+DEFINE_PER_CPU(struct seg6_bpf_srh_state, seg6_bpf_srh_states);
+
+bool seg6_bpf_has_valid_srh(struct sk_buff *skb)
+{
+	struct seg6_bpf_srh_state *srh_state =
+		this_cpu_ptr(&seg6_bpf_srh_states);
+	struct ipv6_sr_hdr *srh = srh_state->srh;
+
+	if (unlikely(srh == NULL))
+		return false;
+
+	if (unlikely(!srh_state->valid)) {
+		if ((srh_state->hdrlen & 7) != 0)
+			return false;
+
+		srh->hdrlen = (u8)(srh_state->hdrlen >> 3);
+		if (!seg6_validate_srh(srh, (srh->hdrlen + 1) << 3, true))
+			return false;
+
+		srh_state->valid = true;
+	}
+
+	return true;
+}
+
+static int input_action_end_bpf(struct sk_buff *skb,
+				struct seg6_local_lwt *slwt)
+{
+	struct seg6_bpf_srh_state *srh_state =
+		this_cpu_ptr(&seg6_bpf_srh_states);
+	struct ipv6_sr_hdr *srh;
+	int ret;
+
+	srh = get_and_validate_srh(skb);
+	if (!srh) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+	advance_nextseg(srh, &ipv6_hdr(skb)->daddr);
+
+	/* preempt_disable is needed to protect the per-CPU buffer srh_state,
+	 * which is also accessed by the bpf_lwt_seg6_* helpers
+	 */
+	preempt_disable();
+	srh_state->srh = srh;
+	srh_state->hdrlen = srh->hdrlen << 3;
+	srh_state->valid = true;
+
+	rcu_read_lock();
+	bpf_compute_data_pointers(skb);
+	ret = bpf_prog_run_save_cb(slwt->bpf.prog, skb);
+	rcu_read_unlock();
+
+	switch (ret) {
+	case BPF_OK:
+	case BPF_REDIRECT:
+		break;
+	case BPF_DROP:
+		goto drop;
+	default:
+		pr_warn_once("bpf-seg6local: Illegal return value %u\n", ret);
+		goto drop;
+	}
+
+	if (srh_state->srh && !seg6_bpf_has_valid_srh(skb))
+		goto drop;
+
+	preempt_enable();
+	if (ret != BPF_REDIRECT)
+		seg6_lookup_nexthop(skb, NULL, 0);
+
+	return dst_input(skb);
+
+drop:
+	preempt_enable();
+	kfree_skb(skb);
+	return -EINVAL;
+}
+
+static struct seg6_action_desc seg6_action_table[] = {
+	{
+		.action		= SEG6_LOCAL_ACTION_END,
+		.attrs		= 0,
+		.optattrs	= SEG6_F_LOCAL_COUNTERS |
+				  SEG6_F_ATTR(SEG6_LOCAL_FLAVORS),
+		.input		= input_action_end,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_X,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_NH6),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_x,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_T,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_TABLE),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_t,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_DX2,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_OIF),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_dx2,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_DX6,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_NH6),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_dx6,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_DX4,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_NH4),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_dx4,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_DT4,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_VRFTABLE),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+#ifdef CONFIG_NET_L3_MASTER_DEV
+		.input		= input_action_end_dt4,
+		.slwt_ops	= {
+					.build_state = seg6_end_dt4_build,
+				  },
+#endif
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_DT6,
+#ifdef CONFIG_NET_L3_MASTER_DEV
+		.attrs		= 0,
+		.optattrs	= SEG6_F_LOCAL_COUNTERS		|
+				  SEG6_F_ATTR(SEG6_LOCAL_TABLE) |
+				  SEG6_F_ATTR(SEG6_LOCAL_VRFTABLE),
+		.slwt_ops	= {
+					.build_state = seg6_end_dt6_build,
+				  },
+#else
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_TABLE),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+#endif
+		.input		= input_action_end_dt6,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_DT46,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_VRFTABLE),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+#ifdef CONFIG_NET_L3_MASTER_DEV
+		.input		= input_action_end_dt46,
+		.slwt_ops	= {
+					.build_state = seg6_end_dt46_build,
+				  },
+#endif
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_B6,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_SRH),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_b6,
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_B6_ENCAP,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_SRH),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_b6_encap,
+		.static_headroom	= sizeof(struct ipv6hdr),
+	},
+	{
+		.action		= SEG6_LOCAL_ACTION_END_BPF,
+		.attrs		= SEG6_F_ATTR(SEG6_LOCAL_BPF),
+		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.input		= input_action_end_bpf,
+	},
+
+};
+
+static struct seg6_action_desc *__get_action_desc(int action)
+{
+	struct seg6_action_desc *desc;
+	int i, count;
+
+	count = ARRAY_SIZE(seg6_action_table);
+	for (i = 0; i < count; i++) {
+		desc = &seg6_action_table[i];
+		if (desc->action == action)
+			return desc;
+	}
+
+	return NULL;
+}
+
+static bool seg6_lwtunnel_counters_enabled(struct seg6_local_lwt *slwt)
+{
+	return slwt->parsed_optattrs & SEG6_F_LOCAL_COUNTERS;
+}
+
+static void seg6_local_update_counters(struct seg6_local_lwt *slwt,
+				       unsigned int len, int err)
+{
+	struct pcpu_seg6_local_counters *pcounters;
+
+	pcounters = this_cpu_ptr(slwt->pcpu_counters);
+	u64_stats_update_begin(&pcounters->syncp);
+
+	if (likely(!err)) {
+		u64_stats_inc(&pcounters->packets);
+		u64_stats_add(&pcounters->bytes, len);
+	} else {
+		u64_stats_inc(&pcounters->errors);
+	}
+
+	u64_stats_update_end(&pcounters->syncp);
+}
+
+static int seg6_local_input_core(struct net *net, struct sock *sk,
+				 struct sk_buff *skb)
+{
+	struct dst_entry *orig_dst = skb_dst(skb);
+	struct seg6_action_desc *desc;
+	struct seg6_local_lwt *slwt;
+	unsigned int len = skb->len;
+	int rc;
+
+	slwt = seg6_local_lwtunnel(orig_dst->lwtstate);
+	desc = slwt->desc;
+
+	rc = desc->input(skb, slwt);
+
+	if (!seg6_lwtunnel_counters_enabled(slwt))
+		return rc;
+
+	seg6_local_update_counters(slwt, len, rc);
+
+	return rc;
+}
+
+static int seg6_local_input(struct sk_buff *skb)
+{
+	if (skb->protocol != htons(ETH_P_IPV6)) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
+	if (static_branch_unlikely(&nf_hooks_lwtunnel_enabled))
+		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_IN,
+			       dev_net(skb->dev), NULL, skb, skb->dev, NULL,
+			       seg6_local_input_core);
+
+	return seg6_local_input_core(dev_net(skb->dev), NULL, skb);
+}
+
+static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = {
+	[SEG6_LOCAL_ACTION]	= { .type = NLA_U32 },
+	[SEG6_LOCAL_SRH]	= { .type = NLA_BINARY },
+	[SEG6_LOCAL_TABLE]	= { .type = NLA_U32 },
+	[SEG6_LOCAL_VRFTABLE]	= { .type = NLA_U32 },
+	[SEG6_LOCAL_NH4]	= { .type = NLA_BINARY,
+				    .len = sizeof(struct in_addr) },
+	[SEG6_LOCAL_NH6]	= { .type = NLA_BINARY,
+				    .len = sizeof(struct in6_addr) },
+	[SEG6_LOCAL_IIF]	= { .type = NLA_U32 },
+	[SEG6_LOCAL_OIF]	= { .type = NLA_U32 },
+	[SEG6_LOCAL_BPF]	= { .type = NLA_NESTED },
+	[SEG6_LOCAL_COUNTERS]	= { .type = NLA_NESTED },
+	[SEG6_LOCAL_FLAVORS]	= { .type = NLA_NESTED },
+};
+
+static int parse_nla_srh(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			 struct netlink_ext_ack *extack)
+{
+	struct ipv6_sr_hdr *srh;
+	int len;
+
+	srh = nla_data(attrs[SEG6_LOCAL_SRH]);
+	len = nla_len(attrs[SEG6_LOCAL_SRH]);
+
+	/* SRH must contain at least one segment */
+	if (len < sizeof(*srh) + sizeof(struct in6_addr))
+		return -EINVAL;
+
+	if (!seg6_validate_srh(srh, len, false))
+		return -EINVAL;
+
+	slwt->srh = kmemdup(srh, len, GFP_KERNEL);
+	if (!slwt->srh)
+		return -ENOMEM;
+
+	slwt->headroom += len;
+
+	return 0;
+}
+
+static int put_nla_srh(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct ipv6_sr_hdr *srh;
+	struct nlattr *nla;
+	int len;
+
+	srh = slwt->srh;
+	len = (srh->hdrlen + 1) << 3;
+
+	nla = nla_reserve(skb, SEG6_LOCAL_SRH, len);
+	if (!nla)
+		return -EMSGSIZE;
+
+	memcpy(nla_data(nla), srh, len);
+
+	return 0;
+}
+
+static int cmp_nla_srh(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	int len = (a->srh->hdrlen + 1) << 3;
+
+	if (len != ((b->srh->hdrlen + 1) << 3))
+		return 1;
+
+	return memcmp(a->srh, b->srh, len);
+}
+
+static void destroy_attr_srh(struct seg6_local_lwt *slwt)
+{
+	kfree(slwt->srh);
+}
+
+static int parse_nla_table(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			   struct netlink_ext_ack *extack)
+{
+	slwt->table = nla_get_u32(attrs[SEG6_LOCAL_TABLE]);
+
+	return 0;
+}
+
+static int put_nla_table(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	if (nla_put_u32(skb, SEG6_LOCAL_TABLE, slwt->table))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int cmp_nla_table(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	if (a->table != b->table)
+		return 1;
+
+	return 0;
+}
+
+static struct
+seg6_end_dt_info *seg6_possible_end_dt_info(struct seg6_local_lwt *slwt)
+{
+#ifdef CONFIG_NET_L3_MASTER_DEV
+	return &slwt->dt_info;
+#else
+	return ERR_PTR(-EOPNOTSUPP);
+#endif
+}
+
+static int parse_nla_vrftable(struct nlattr **attrs,
+			      struct seg6_local_lwt *slwt,
+			      struct netlink_ext_ack *extack)
+{
+	struct seg6_end_dt_info *info = seg6_possible_end_dt_info(slwt);
+
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
+	info->vrf_table = nla_get_u32(attrs[SEG6_LOCAL_VRFTABLE]);
+
+	return 0;
+}
+
+static int put_nla_vrftable(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct seg6_end_dt_info *info = seg6_possible_end_dt_info(slwt);
+
+	if (IS_ERR(info))
+		return PTR_ERR(info);
+
+	if (nla_put_u32(skb, SEG6_LOCAL_VRFTABLE, info->vrf_table))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int cmp_nla_vrftable(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	struct seg6_end_dt_info *info_a = seg6_possible_end_dt_info(a);
+	struct seg6_end_dt_info *info_b = seg6_possible_end_dt_info(b);
+
+	if (info_a->vrf_table != info_b->vrf_table)
+		return 1;
+
+	return 0;
+}
+
+static int parse_nla_nh4(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			 struct netlink_ext_ack *extack)
+{
+	memcpy(&slwt->nh4, nla_data(attrs[SEG6_LOCAL_NH4]),
+	       sizeof(struct in_addr));
+
+	return 0;
+}
+
+static int put_nla_nh4(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct nlattr *nla;
+
+	nla = nla_reserve(skb, SEG6_LOCAL_NH4, sizeof(struct in_addr));
+	if (!nla)
+		return -EMSGSIZE;
+
+	memcpy(nla_data(nla), &slwt->nh4, sizeof(struct in_addr));
+
+	return 0;
+}
+
+static int cmp_nla_nh4(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	return memcmp(&a->nh4, &b->nh4, sizeof(struct in_addr));
+}
+
+static int parse_nla_nh6(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			 struct netlink_ext_ack *extack)
+{
+	memcpy(&slwt->nh6, nla_data(attrs[SEG6_LOCAL_NH6]),
+	       sizeof(struct in6_addr));
+
+	return 0;
+}
+
+static int put_nla_nh6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct nlattr *nla;
+
+	nla = nla_reserve(skb, SEG6_LOCAL_NH6, sizeof(struct in6_addr));
+	if (!nla)
+		return -EMSGSIZE;
+
+	memcpy(nla_data(nla), &slwt->nh6, sizeof(struct in6_addr));
+
+	return 0;
+}
+
+static int cmp_nla_nh6(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	return memcmp(&a->nh6, &b->nh6, sizeof(struct in6_addr));
+}
+
+static int parse_nla_iif(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			 struct netlink_ext_ack *extack)
+{
+	slwt->iif = nla_get_u32(attrs[SEG6_LOCAL_IIF]);
+
+	return 0;
+}
+
+static int put_nla_iif(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	if (nla_put_u32(skb, SEG6_LOCAL_IIF, slwt->iif))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int cmp_nla_iif(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	if (a->iif != b->iif)
+		return 1;
+
+	return 0;
+}
+
+static int parse_nla_oif(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			 struct netlink_ext_ack *extack)
+{
+	slwt->oif = nla_get_u32(attrs[SEG6_LOCAL_OIF]);
+
+	return 0;
+}
+
+static int put_nla_oif(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	if (nla_put_u32(skb, SEG6_LOCAL_OIF, slwt->oif))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int cmp_nla_oif(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	if (a->oif != b->oif)
+		return 1;
+
+	return 0;
+}
+
+#define MAX_PROG_NAME 256
+static const struct nla_policy bpf_prog_policy[SEG6_LOCAL_BPF_PROG_MAX + 1] = {
+	[SEG6_LOCAL_BPF_PROG]	   = { .type = NLA_U32, },
+	[SEG6_LOCAL_BPF_PROG_NAME] = { .type = NLA_NUL_STRING,
+				       .len = MAX_PROG_NAME },
+};
+
+static int parse_nla_bpf(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			 struct netlink_ext_ack *extack)
+{
+	struct nlattr *tb[SEG6_LOCAL_BPF_PROG_MAX + 1];
+	struct bpf_prog *p;
+	int ret;
+	u32 fd;
+
+	ret = nla_parse_nested_deprecated(tb, SEG6_LOCAL_BPF_PROG_MAX,
+					  attrs[SEG6_LOCAL_BPF],
+					  bpf_prog_policy, NULL);
+	if (ret < 0)
+		return ret;
+
+	if (!tb[SEG6_LOCAL_BPF_PROG] || !tb[SEG6_LOCAL_BPF_PROG_NAME])
+		return -EINVAL;
+
+	slwt->bpf.name = nla_memdup(tb[SEG6_LOCAL_BPF_PROG_NAME], GFP_KERNEL);
+	if (!slwt->bpf.name)
+		return -ENOMEM;
+
+	fd = nla_get_u32(tb[SEG6_LOCAL_BPF_PROG]);
+	p = bpf_prog_get_type(fd, BPF_PROG_TYPE_LWT_SEG6LOCAL);
+	if (IS_ERR(p)) {
+		kfree(slwt->bpf.name);
+		return PTR_ERR(p);
+	}
+
+	slwt->bpf.prog = p;
+	return 0;
+}
+
+static int put_nla_bpf(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct nlattr *nest;
+
+	if (!slwt->bpf.prog)
+		return 0;
+
+	nest = nla_nest_start_noflag(skb, SEG6_LOCAL_BPF);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, SEG6_LOCAL_BPF_PROG, slwt->bpf.prog->aux->id))
+		return -EMSGSIZE;
+
+	if (slwt->bpf.name &&
+	    nla_put_string(skb, SEG6_LOCAL_BPF_PROG_NAME, slwt->bpf.name))
+		return -EMSGSIZE;
+
+	return nla_nest_end(skb, nest);
+}
+
+static int cmp_nla_bpf(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	if (!a->bpf.name && !b->bpf.name)
+		return 0;
+
+	if (!a->bpf.name || !b->bpf.name)
+		return 1;
+
+	return strcmp(a->bpf.name, b->bpf.name);
+}
+
+static void destroy_attr_bpf(struct seg6_local_lwt *slwt)
+{
+	kfree(slwt->bpf.name);
+	if (slwt->bpf.prog)
+		bpf_prog_put(slwt->bpf.prog);
+}
+
+static const struct
+nla_policy seg6_local_counters_policy[SEG6_LOCAL_CNT_MAX + 1] = {
+	[SEG6_LOCAL_CNT_PACKETS]	= { .type = NLA_U64 },
+	[SEG6_LOCAL_CNT_BYTES]		= { .type = NLA_U64 },
+	[SEG6_LOCAL_CNT_ERRORS]		= { .type = NLA_U64 },
+};
+
+static int parse_nla_counters(struct nlattr **attrs,
+			      struct seg6_local_lwt *slwt,
+			      struct netlink_ext_ack *extack)
+{
+	struct pcpu_seg6_local_counters __percpu *pcounters;
+	struct nlattr *tb[SEG6_LOCAL_CNT_MAX + 1];
+	int ret;
+
+	ret = nla_parse_nested_deprecated(tb, SEG6_LOCAL_CNT_MAX,
+					  attrs[SEG6_LOCAL_COUNTERS],
+					  seg6_local_counters_policy, NULL);
+	if (ret < 0)
+		return ret;
+
+	/* basic support for SRv6 Behavior counters requires at least:
+	 * packets, bytes and errors.
+	 */
+	if (!tb[SEG6_LOCAL_CNT_PACKETS] || !tb[SEG6_LOCAL_CNT_BYTES] ||
+	    !tb[SEG6_LOCAL_CNT_ERRORS])
+		return -EINVAL;
+
+	/* counters are always zero initialized */
+	pcounters = seg6_local_alloc_pcpu_counters(GFP_KERNEL);
+	if (!pcounters)
+		return -ENOMEM;
+
+	slwt->pcpu_counters = pcounters;
+
+	return 0;
+}
+
+static int seg6_local_fill_nla_counters(struct sk_buff *skb,
+					struct seg6_local_counters *counters)
+{
+	if (nla_put_u64_64bit(skb, SEG6_LOCAL_CNT_PACKETS, counters->packets,
+			      SEG6_LOCAL_CNT_PAD))
+		return -EMSGSIZE;
+
+	if (nla_put_u64_64bit(skb, SEG6_LOCAL_CNT_BYTES, counters->bytes,
+			      SEG6_LOCAL_CNT_PAD))
+		return -EMSGSIZE;
+
+	if (nla_put_u64_64bit(skb, SEG6_LOCAL_CNT_ERRORS, counters->errors,
+			      SEG6_LOCAL_CNT_PAD))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int put_nla_counters(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct seg6_local_counters counters = { 0, 0, 0 };
+	struct nlattr *nest;
+	int rc, i;
+
+	nest = nla_nest_start(skb, SEG6_LOCAL_COUNTERS);
+	if (!nest)
+		return -EMSGSIZE;
+
+	for_each_possible_cpu(i) {
+		struct pcpu_seg6_local_counters *pcounters;
+		u64 packets, bytes, errors;
+		unsigned int start;
+
+		pcounters = per_cpu_ptr(slwt->pcpu_counters, i);
+		do {
+			start = u64_stats_fetch_begin_irq(&pcounters->syncp);
+
+			packets = u64_stats_read(&pcounters->packets);
+			bytes = u64_stats_read(&pcounters->bytes);
+			errors = u64_stats_read(&pcounters->errors);
+
+		} while (u64_stats_fetch_retry_irq(&pcounters->syncp, start));
+
+		counters.packets += packets;
+		counters.bytes += bytes;
+		counters.errors += errors;
+	}
+
+	rc = seg6_local_fill_nla_counters(skb, &counters);
+	if (rc < 0) {
+		nla_nest_cancel(skb, nest);
+		return rc;
+	}
+
+	return nla_nest_end(skb, nest);
+}
+
+static int cmp_nla_counters(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	/* a and b are equal if both have pcpu_counters set or not */
+	return (!!((unsigned long)a->pcpu_counters)) ^
+		(!!((unsigned long)b->pcpu_counters));
+}
+
+static void destroy_attr_counters(struct seg6_local_lwt *slwt)
+{
+	free_percpu(slwt->pcpu_counters);
+}
+
+static const
+struct nla_policy seg6_local_flavors_policy[SEG6_LOCAL_FLV_MAX + 1] = {
+	[SEG6_LOCAL_FLV_OPERATION]	= { .type = NLA_U32 },
+	[SEG6_LOCAL_FLV_LCBLOCK_BITS]	= { .type = NLA_U8 },
+	[SEG6_LOCAL_FLV_LCNODE_FN_BITS]	= { .type = NLA_U8 },
+};
+
+/* check whether the lengths of the Locator-Block and Locator-Node Function
+ * are compatible with the dimension of a C-SID container.
+ */
+static int seg6_chk_next_csid_cfg(__u8 block_len, __u8 func_len)
+{
+	/* Locator-Block and Locator-Node Function cannot exceed 128 bits
+	 * (i.e. C-SID container lenghts).
+	 */
+	if (next_csid_chk_cntr_bits(block_len, func_len))
+		return -EINVAL;
+
+	/* Locator-Block length must be greater than zero and evenly divisible
+	 * by 8. There must be room for a Locator-Node Function, at least.
+	 */
+	if (next_csid_chk_lcblock_bits(block_len))
+		return -EINVAL;
+
+	/* Locator-Node Function length must be greater than zero and evenly
+	 * divisible by 8. There must be room for the Locator-Block.
+	 */
+	if (next_csid_chk_lcnode_fn_bits(func_len))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int seg6_parse_nla_next_csid_cfg(struct nlattr **tb,
+					struct seg6_flavors_info *finfo,
+					struct netlink_ext_ack *extack)
+{
+	__u8 func_len = SEG6_LOCAL_LCNODE_FN_DBITS;
+	__u8 block_len = SEG6_LOCAL_LCBLOCK_DBITS;
+	int rc;
+
+	if (tb[SEG6_LOCAL_FLV_LCBLOCK_BITS])
+		block_len = nla_get_u8(tb[SEG6_LOCAL_FLV_LCBLOCK_BITS]);
+
+	if (tb[SEG6_LOCAL_FLV_LCNODE_FN_BITS])
+		func_len = nla_get_u8(tb[SEG6_LOCAL_FLV_LCNODE_FN_BITS]);
+
+	rc = seg6_chk_next_csid_cfg(block_len, func_len);
+	if (rc < 0) {
+		NL_SET_ERR_MSG(extack,
+			       "Invalid Locator Block/Node Function lengths");
+		return rc;
+	}
+
+	finfo->lcblock_bits = block_len;
+	finfo->lcnode_func_bits = func_len;
+
+	return 0;
+}
+
+static int parse_nla_flavors(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			     struct netlink_ext_ack *extack)
+{
+	struct seg6_flavors_info *finfo = &slwt->flv_info;
+	struct nlattr *tb[SEG6_LOCAL_FLV_MAX + 1];
+	unsigned long fops;
+	int rc;
+
+	rc = nla_parse_nested_deprecated(tb, SEG6_LOCAL_FLV_MAX,
+					 attrs[SEG6_LOCAL_FLAVORS],
+					 seg6_local_flavors_policy, NULL);
+	if (rc < 0)
+		return rc;
+
+	/* this attribute MUST always be present since it represents the Flavor
+	 * operation(s) to be carried out.
+	 */
+	if (!tb[SEG6_LOCAL_FLV_OPERATION])
+		return -EINVAL;
+
+	fops = nla_get_u32(tb[SEG6_LOCAL_FLV_OPERATION]);
+	if (fops & ~SEG6_LOCAL_FLV_SUPP_OPS) {
+		NL_SET_ERR_MSG(extack, "Unsupported Flavor operation(s)");
+		return -EOPNOTSUPP;
+	}
+
+	finfo->flv_ops = fops;
+
+	if (seg6_next_csid_enabled(fops)) {
+		/* Locator-Block and Locator-Node Function lengths can be
+		 * provided by the user space. Otherwise, default values are
+		 * applied.
+		 */
+		rc = seg6_parse_nla_next_csid_cfg(tb, finfo, extack);
+		if (rc < 0)
+			return rc;
+	}
+
+	return 0;
+}
+
+static int seg6_fill_nla_next_csid_cfg(struct sk_buff *skb,
+				       struct seg6_flavors_info *finfo)
+{
+	if (nla_put_u8(skb, SEG6_LOCAL_FLV_LCBLOCK_BITS, finfo->lcblock_bits))
+		return -EMSGSIZE;
+
+	if (nla_put_u8(skb, SEG6_LOCAL_FLV_LCNODE_FN_BITS,
+		       finfo->lcnode_func_bits))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int put_nla_flavors(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+{
+	struct seg6_flavors_info *finfo = &slwt->flv_info;
+	__u32 fops = finfo->flv_ops;
+	struct nlattr *nest;
+	int rc;
+
+	nest = nla_nest_start(skb, SEG6_LOCAL_FLAVORS);
+	if (!nest)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, SEG6_LOCAL_FLV_OPERATION, fops)) {
+		rc = -EMSGSIZE;
+		goto err;
+	}
+
+	if (seg6_next_csid_enabled(fops)) {
+		rc = seg6_fill_nla_next_csid_cfg(skb, finfo);
+		if (rc < 0)
+			goto err;
+	}
+
+	return nla_nest_end(skb, nest);
+
+err:
+	nla_nest_cancel(skb, nest);
+	return rc;
+}
+
+static int seg6_cmp_nla_next_csid_cfg(struct seg6_flavors_info *finfo_a,
+				      struct seg6_flavors_info *finfo_b)
+{
+	if (finfo_a->lcblock_bits != finfo_b->lcblock_bits)
+		return 1;
+
+	if (finfo_a->lcnode_func_bits != finfo_b->lcnode_func_bits)
+		return 1;
+
+	return 0;
+}
+
+static int cmp_nla_flavors(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
+{
+	struct seg6_flavors_info *finfo_a = &a->flv_info;
+	struct seg6_flavors_info *finfo_b = &b->flv_info;
+
+	if (finfo_a->flv_ops != finfo_b->flv_ops)
+		return 1;
+
+	if (seg6_next_csid_enabled(finfo_a->flv_ops)) {
+		if (seg6_cmp_nla_next_csid_cfg(finfo_a, finfo_b))
+			return 1;
+	}
+
+	return 0;
+}
+
+static int encap_size_flavors(struct seg6_local_lwt *slwt)
+{
+	struct seg6_flavors_info *finfo = &slwt->flv_info;
+	int nlsize;
+
+	nlsize = nla_total_size(0) +	/* nest SEG6_LOCAL_FLAVORS */
+		 nla_total_size(4);	/* SEG6_LOCAL_FLV_OPERATION */
+
+	if (seg6_next_csid_enabled(finfo->flv_ops))
+		nlsize += nla_total_size(1) + /* SEG6_LOCAL_FLV_LCBLOCK_BITS */
+			  nla_total_size(1); /* SEG6_LOCAL_FLV_LCNODE_FN_BITS */
+
+	return nlsize;
+}
+
+struct seg6_action_param {
+	int (*parse)(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+		     struct netlink_ext_ack *extack);
+	int (*put)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
+	int (*cmp)(struct seg6_local_lwt *a, struct seg6_local_lwt *b);
+
+	/* optional destroy() callback useful for releasing resources which
+	 * have been previously acquired in the corresponding parse()
+	 * function.
+	 */
+	void (*destroy)(struct seg6_local_lwt *slwt);
+};
+
+static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
+	[SEG6_LOCAL_SRH]	= { .parse = parse_nla_srh,
+				    .put = put_nla_srh,
+				    .cmp = cmp_nla_srh,
+				    .destroy = destroy_attr_srh },
+
+	[SEG6_LOCAL_TABLE]	= { .parse = parse_nla_table,
+				    .put = put_nla_table,
+				    .cmp = cmp_nla_table },
+
+	[SEG6_LOCAL_NH4]	= { .parse = parse_nla_nh4,
+				    .put = put_nla_nh4,
+				    .cmp = cmp_nla_nh4 },
+
+	[SEG6_LOCAL_NH6]	= { .parse = parse_nla_nh6,
+				    .put = put_nla_nh6,
+				    .cmp = cmp_nla_nh6 },
+
+	[SEG6_LOCAL_IIF]	= { .parse = parse_nla_iif,
+				    .put = put_nla_iif,
+				    .cmp = cmp_nla_iif },
+
+	[SEG6_LOCAL_OIF]	= { .parse = parse_nla_oif,
+				    .put = put_nla_oif,
+				    .cmp = cmp_nla_oif },
+
+	[SEG6_LOCAL_BPF]	= { .parse = parse_nla_bpf,
+				    .put = put_nla_bpf,
+				    .cmp = cmp_nla_bpf,
+				    .destroy = destroy_attr_bpf },
+
+	[SEG6_LOCAL_VRFTABLE]	= { .parse = parse_nla_vrftable,
+				    .put = put_nla_vrftable,
+				    .cmp = cmp_nla_vrftable },
+
+	[SEG6_LOCAL_COUNTERS]	= { .parse = parse_nla_counters,
+				    .put = put_nla_counters,
+				    .cmp = cmp_nla_counters,
+				    .destroy = destroy_attr_counters },
+
+	[SEG6_LOCAL_FLAVORS]	= { .parse = parse_nla_flavors,
+				    .put = put_nla_flavors,
+				    .cmp = cmp_nla_flavors },
+};
+
+/* call the destroy() callback (if available) for each set attribute in
+ * @parsed_attrs, starting from the first attribute up to the @max_parsed
+ * (excluded) attribute.
+ */
+static void __destroy_attrs(unsigned long parsed_attrs, int max_parsed,
+			    struct seg6_local_lwt *slwt)
+{
+	struct seg6_action_param *param;
+	int i;
+
+	/* Every required seg6local attribute is identified by an ID which is
+	 * encoded as a flag (i.e: 1 << ID) in the 'attrs' bitmask;
+	 *
+	 * We scan the 'parsed_attrs' bitmask, starting from the first attribute
+	 * up to the @max_parsed (excluded) attribute.
+	 * For each set attribute, we retrieve the corresponding destroy()
+	 * callback. If the callback is not available, then we skip to the next
+	 * attribute; otherwise, we call the destroy() callback.
+	 */
+	for (i = SEG6_LOCAL_SRH; i < max_parsed; ++i) {
+		if (!(parsed_attrs & SEG6_F_ATTR(i)))
+			continue;
+
+		param = &seg6_action_params[i];
+
+		if (param->destroy)
+			param->destroy(slwt);
+	}
+}
+
+/* release all the resources that may have been acquired during parsing
+ * operations.
+ */
+static void destroy_attrs(struct seg6_local_lwt *slwt)
+{
+	unsigned long attrs = slwt->desc->attrs | slwt->parsed_optattrs;
+
+	__destroy_attrs(attrs, SEG6_LOCAL_MAX + 1, slwt);
+}
+
+static int parse_nla_optional_attrs(struct nlattr **attrs,
+				    struct seg6_local_lwt *slwt,
+				    struct netlink_ext_ack *extack)
+{
+	struct seg6_action_desc *desc = slwt->desc;
+	unsigned long parsed_optattrs = 0;
+	struct seg6_action_param *param;
+	int err, i;
+
+	for (i = SEG6_LOCAL_SRH; i < SEG6_LOCAL_MAX + 1; ++i) {
+		if (!(desc->optattrs & SEG6_F_ATTR(i)) || !attrs[i])
+			continue;
+
+		/* once here, the i-th attribute is provided by the
+		 * userspace AND it is identified optional as well.
+		 */
+		param = &seg6_action_params[i];
+
+		err = param->parse(attrs, slwt, extack);
+		if (err < 0)
+			goto parse_optattrs_err;
+
+		/* current attribute has been correctly parsed */
+		parsed_optattrs |= SEG6_F_ATTR(i);
+	}
+
+	/* store in the tunnel state all the optional attributed successfully
+	 * parsed.
+	 */
+	slwt->parsed_optattrs = parsed_optattrs;
+
+	return 0;
+
+parse_optattrs_err:
+	__destroy_attrs(parsed_optattrs, i, slwt);
+
+	return err;
+}
+
+/* call the custom constructor of the behavior during its initialization phase
+ * and after that all its attributes have been parsed successfully.
+ */
+static int
+seg6_local_lwtunnel_build_state(struct seg6_local_lwt *slwt, const void *cfg,
+				struct netlink_ext_ack *extack)
+{
+	struct seg6_action_desc *desc = slwt->desc;
+	struct seg6_local_lwtunnel_ops *ops;
+
+	ops = &desc->slwt_ops;
+	if (!ops->build_state)
+		return 0;
+
+	return ops->build_state(slwt, cfg, extack);
+}
+
+/* call the custom destructor of the behavior which is invoked before the
+ * tunnel is going to be destroyed.
+ */
+static void seg6_local_lwtunnel_destroy_state(struct seg6_local_lwt *slwt)
+{
+	struct seg6_action_desc *desc = slwt->desc;
+	struct seg6_local_lwtunnel_ops *ops;
+
+	ops = &desc->slwt_ops;
+	if (!ops->destroy_state)
+		return;
+
+	ops->destroy_state(slwt);
+}
+
+static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt,
+			    struct netlink_ext_ack *extack)
+{
+	struct seg6_action_param *param;
+	struct seg6_action_desc *desc;
+	unsigned long invalid_attrs;
+	int i, err;
+
+	desc = __get_action_desc(slwt->action);
+	if (!desc)
+		return -EINVAL;
+
+	if (!desc->input)
+		return -EOPNOTSUPP;
+
+	slwt->desc = desc;
+	slwt->headroom += desc->static_headroom;
+
+	/* Forcing the desc->optattrs *set* and the desc->attrs *set* to be
+	 * disjoined, this allow us to release acquired resources by optional
+	 * attributes and by required attributes independently from each other
+	 * without any interference.
+	 * In other terms, we are sure that we do not release some the acquired
+	 * resources twice.
+	 *
+	 * Note that if an attribute is configured both as required and as
+	 * optional, it means that the user has messed something up in the
+	 * seg6_action_table. Therefore, this check is required for SRv6
+	 * behaviors to work properly.
+	 */
+	invalid_attrs = desc->attrs & desc->optattrs;
+	if (invalid_attrs) {
+		WARN_ONCE(1,
+			  "An attribute cannot be both required AND optional");
+		return -EINVAL;
+	}
+
+	/* parse the required attributes */
+	for (i = SEG6_LOCAL_SRH; i < SEG6_LOCAL_MAX + 1; i++) {
+		if (desc->attrs & SEG6_F_ATTR(i)) {
+			if (!attrs[i])
+				return -EINVAL;
+
+			param = &seg6_action_params[i];
+
+			err = param->parse(attrs, slwt, extack);
+			if (err < 0)
+				goto parse_attrs_err;
+		}
+	}
+
+	/* parse the optional attributes, if any */
+	err = parse_nla_optional_attrs(attrs, slwt, extack);
+	if (err < 0)
+		goto parse_attrs_err;
+
+	return 0;
+
+parse_attrs_err:
+	/* release any resource that may have been acquired during the i-1
+	 * parse() operations.
+	 */
+	__destroy_attrs(desc->attrs, i, slwt);
+
+	return err;
+}
+
+static int seg6_local_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_LOCAL_MAX + 1];
+	struct lwtunnel_state *newts;
+	struct seg6_local_lwt *slwt;
+	int err;
+
+	if (family != AF_INET6)
+		return -EINVAL;
+
+	err = nla_parse_nested_deprecated(tb, SEG6_LOCAL_MAX, nla,
+					  seg6_local_policy, extack);
+
+	if (err < 0)
+		return err;
+
+	if (!tb[SEG6_LOCAL_ACTION])
+		return -EINVAL;
+
+	newts = lwtunnel_state_alloc(sizeof(*slwt));
+	if (!newts)
+		return -ENOMEM;
+
+	slwt = seg6_local_lwtunnel(newts);
+	slwt->action = nla_get_u32(tb[SEG6_LOCAL_ACTION]);
+
+	err = parse_nla_action(tb, slwt, extack);
+	if (err < 0)
+		goto out_free;
+
+	err = seg6_local_lwtunnel_build_state(slwt, cfg, extack);
+	if (err < 0)
+		goto out_destroy_attrs;
+
+	newts->type = LWTUNNEL_ENCAP_SEG6_LOCAL;
+	newts->flags = LWTUNNEL_STATE_INPUT_REDIRECT;
+	newts->headroom = slwt->headroom;
+
+	*ts = newts;
+
+	return 0;
+
+out_destroy_attrs:
+	destroy_attrs(slwt);
+out_free:
+	kfree(newts);
+	return err;
+}
+
+static void seg6_local_destroy_state(struct lwtunnel_state *lwt)
+{
+	struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
+
+	seg6_local_lwtunnel_destroy_state(slwt);
+
+	destroy_attrs(slwt);
+
+	return;
+}
+
+static int seg6_local_fill_encap(struct sk_buff *skb,
+				 struct lwtunnel_state *lwt)
+{
+	struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
+	struct seg6_action_param *param;
+	unsigned long attrs;
+	int i, err;
+
+	if (nla_put_u32(skb, SEG6_LOCAL_ACTION, slwt->action))
+		return -EMSGSIZE;
+
+	attrs = slwt->desc->attrs | slwt->parsed_optattrs;
+
+	for (i = SEG6_LOCAL_SRH; i < SEG6_LOCAL_MAX + 1; i++) {
+		if (attrs & SEG6_F_ATTR(i)) {
+			param = &seg6_action_params[i];
+			err = param->put(skb, slwt);
+			if (err < 0)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+static int seg6_local_get_encap_size(struct lwtunnel_state *lwt)
+{
+	struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
+	unsigned long attrs;
+	int nlsize;
+
+	nlsize = nla_total_size(4); /* action */
+
+	attrs = slwt->desc->attrs | slwt->parsed_optattrs;
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_SRH))
+		nlsize += nla_total_size((slwt->srh->hdrlen + 1) << 3);
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_TABLE))
+		nlsize += nla_total_size(4);
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_NH4))
+		nlsize += nla_total_size(4);
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_NH6))
+		nlsize += nla_total_size(16);
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_IIF))
+		nlsize += nla_total_size(4);
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_OIF))
+		nlsize += nla_total_size(4);
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_BPF))
+		nlsize += nla_total_size(sizeof(struct nlattr)) +
+		       nla_total_size(MAX_PROG_NAME) +
+		       nla_total_size(4);
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_VRFTABLE))
+		nlsize += nla_total_size(4);
+
+	if (attrs & SEG6_F_LOCAL_COUNTERS)
+		nlsize += nla_total_size(0) + /* nest SEG6_LOCAL_COUNTERS */
+			  /* SEG6_LOCAL_CNT_PACKETS */
+			  nla_total_size_64bit(sizeof(__u64)) +
+			  /* SEG6_LOCAL_CNT_BYTES */
+			  nla_total_size_64bit(sizeof(__u64)) +
+			  /* SEG6_LOCAL_CNT_ERRORS */
+			  nla_total_size_64bit(sizeof(__u64));
+
+	if (attrs & SEG6_F_ATTR(SEG6_LOCAL_FLAVORS))
+		nlsize += encap_size_flavors(slwt);
+
+	return nlsize;
+}
+
+static int seg6_local_cmp_encap(struct lwtunnel_state *a,
+				struct lwtunnel_state *b)
+{
+	struct seg6_local_lwt *slwt_a, *slwt_b;
+	struct seg6_action_param *param;
+	unsigned long attrs_a, attrs_b;
+	int i;
+
+	slwt_a = seg6_local_lwtunnel(a);
+	slwt_b = seg6_local_lwtunnel(b);
+
+	if (slwt_a->action != slwt_b->action)
+		return 1;
+
+	attrs_a = slwt_a->desc->attrs | slwt_a->parsed_optattrs;
+	attrs_b = slwt_b->desc->attrs | slwt_b->parsed_optattrs;
+
+	if (attrs_a != attrs_b)
+		return 1;
+
+	for (i = SEG6_LOCAL_SRH; i < SEG6_LOCAL_MAX + 1; i++) {
+		if (attrs_a & SEG6_F_ATTR(i)) {
+			param = &seg6_action_params[i];
+			if (param->cmp(slwt_a, slwt_b))
+				return 1;
+		}
+	}
+
+	return 0;
+}
+
+static const struct lwtunnel_encap_ops seg6_local_ops = {
+	.build_state	= seg6_local_build_state,
+	.destroy_state	= seg6_local_destroy_state,
+	.input		= seg6_local_input,
+	.fill_encap	= seg6_local_fill_encap,
+	.get_encap_size	= seg6_local_get_encap_size,
+	.cmp_encap	= seg6_local_cmp_encap,
+	.owner		= THIS_MODULE,
+};
+
+int __init seg6_local_init(void)
+{
+	/* If the max total number of defined attributes is reached, then your
+	 * kernel build stops here.
+	 *
+	 * This check is required to avoid arithmetic overflows when processing
+	 * behavior attributes and the maximum number of defined attributes
+	 * exceeds the allowed value.
+	 */
+	BUILD_BUG_ON(SEG6_LOCAL_MAX + 1 > BITS_PER_TYPE(unsigned long));
+
+	/* If the default NEXT-C-SID Locator-Block/Node Function lengths (in
+	 * bits) have been changed with invalid values, kernel build stops
+	 * here.
+	 */
+	BUILD_BUG_ON(next_csid_chk_cntr_bits(SEG6_LOCAL_LCBLOCK_DBITS,
+					     SEG6_LOCAL_LCNODE_FN_DBITS));
+	BUILD_BUG_ON(next_csid_chk_lcblock_bits(SEG6_LOCAL_LCBLOCK_DBITS));
+	BUILD_BUG_ON(next_csid_chk_lcnode_fn_bits(SEG6_LOCAL_LCNODE_FN_DBITS));
+
+	return lwtunnel_encap_add_ops(&seg6_local_ops,
+				      LWTUNNEL_ENCAP_SEG6_LOCAL);
+}
+
+void seg6_local_exit(void)
+{
+	lwtunnel_encap_del_ops(&seg6_local_ops, LWTUNNEL_ENCAP_SEG6_LOCAL);
+}