1 files changed, 369 insertions, 57 deletions

diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
index 2dc40b3f373e..8370726ae7bf 100644
--- a/net/ipv6/seg6_local.c
+++ b/net/ipv6/seg6_local.c
@@ -7,6 +7,7 @@
  *  eBPF support: Mathieu Xhonneux <m.xhonneux@gmail.com>
  */
 
+#include <linux/filter.h>
 #include <linux/types.h>
 #include <linux/skbuff.h>
 #include <linux/net.h>
@@ -72,6 +73,55 @@ struct bpf_lwt_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,
@@ -135,6 +185,8 @@ struct seg6_local_lwt {
 #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;
@@ -150,40 +202,11 @@ 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_srh(struct sk_buff *skb, int flags)
-{
-	struct ipv6_sr_hdr *srh;
-	int len, srhoff = 0;
-
-	if (ipv6_find_hdr(skb, &srhoff, IPPROTO_ROUTING, NULL, &flags) < 0)
-		return NULL;
-
-	if (!pskb_may_pull(skb, srhoff + sizeof(*srh)))
-		return NULL;
-
-	srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
-
-	len = (srh->hdrlen + 1) << 3;
-
-	if (!pskb_may_pull(skb, srhoff + len))
-		return NULL;
-
-	/* note that pskb_may_pull may change pointers in header;
-	 * for this reason it is necessary to reload them when needed.
-	 */
-	srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
-
-	if (!seg6_validate_srh(srh, len, true))
-		return NULL;
-
-	return srh;
-}
-
 static struct ipv6_sr_hdr *get_and_validate_srh(struct sk_buff *skb)
 {
 	struct ipv6_sr_hdr *srh;
 
-	srh = get_srh(skb, IP6_FH_F_SKIP_RH);
+	srh = seg6_get_srh(skb, IP6_FH_F_SKIP_RH);
 	if (!srh)
 		return NULL;
 
@@ -200,7 +223,7 @@ static bool decap_and_validate(struct sk_buff *skb, int proto)
 	struct ipv6_sr_hdr *srh;
 	unsigned int off = 0;
 
-	srh = get_srh(skb, 0);
+	srh = seg6_get_srh(skb, 0);
 	if (srh && srh->segments_left > 0)
 		return false;
 
@@ -246,6 +269,7 @@ seg6_lookup_any_nexthop(struct sk_buff *skb, struct in6_addr *nhaddr,
 	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;
@@ -298,8 +322,50 @@ int seg6_lookup_nexthop(struct sk_buff *skb,
 	return seg6_lookup_any_nexthop(skb, nhaddr, tbl_id, false);
 }
 
-/* regular endpoint function */
-static int input_action_end(struct sk_buff *skb, struct seg6_local_lwt *slwt)
+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;
 
@@ -318,6 +384,38 @@ drop:
 	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)
 {
@@ -853,7 +951,6 @@ static int input_action_end_b6(struct sk_buff *skb, struct seg6_local_lwt *slwt)
 	if (err)
 		goto drop;
 
-	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 
 	seg6_lookup_nexthop(skb, NULL, 0);
@@ -885,7 +982,6 @@ static int input_action_end_b6_encap(struct sk_buff *skb,
 	if (err)
 		goto drop;
 
-	ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 	skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 
 	seg6_lookup_nexthop(skb, NULL, 0);
@@ -980,7 +1076,8 @@ static struct seg6_action_desc seg6_action_table[] = {
 	{
 		.action		= SEG6_LOCAL_ACTION_END,
 		.attrs		= 0,
-		.optattrs	= SEG6_F_LOCAL_COUNTERS,
+		.optattrs	= SEG6_F_LOCAL_COUNTERS |
+				  SEG6_F_ATTR(SEG6_LOCAL_FLAVORS),
 		.input		= input_action_end,
 	},
 	{
@@ -1161,9 +1258,11 @@ static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = {
 	[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)
+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;
@@ -1220,7 +1319,8 @@ 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)
+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]);
 
@@ -1254,7 +1354,8 @@ seg6_end_dt_info *seg6_possible_end_dt_info(struct seg6_local_lwt *slwt)
 }
 
 static int parse_nla_vrftable(struct nlattr **attrs,
-			      struct seg6_local_lwt *slwt)
+			      struct seg6_local_lwt *slwt,
+			      struct netlink_ext_ack *extack)
 {
 	struct seg6_end_dt_info *info = seg6_possible_end_dt_info(slwt);
 
@@ -1290,7 +1391,8 @@ static int cmp_nla_vrftable(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 	return 0;
 }
 
-static int parse_nla_nh4(struct nlattr **attrs, struct seg6_local_lwt *slwt)
+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));
@@ -1316,7 +1418,8 @@ 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)
+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));
@@ -1342,7 +1445,8 @@ 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)
+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]);
 
@@ -1365,7 +1469,8 @@ static int cmp_nla_iif(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
 	return 0;
 }
 
-static int parse_nla_oif(struct nlattr **attrs, struct seg6_local_lwt *slwt)
+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]);
 
@@ -1395,7 +1500,8 @@ static const struct nla_policy bpf_prog_policy[SEG6_LOCAL_BPF_PROG_MAX + 1] = {
 				       .len = MAX_PROG_NAME },
 };
 
-static int parse_nla_bpf(struct nlattr **attrs, struct seg6_local_lwt *slwt)
+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;
@@ -1473,7 +1579,8 @@ nla_policy seg6_local_counters_policy[SEG6_LOCAL_CNT_MAX + 1] = {
 };
 
 static int parse_nla_counters(struct nlattr **attrs,
-			      struct seg6_local_lwt *slwt)
+			      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];
@@ -1571,8 +1678,195 @@ 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);
+	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);
 
@@ -1622,6 +1916,10 @@ static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
 				    .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
@@ -1643,7 +1941,7 @@ static void __destroy_attrs(unsigned long parsed_attrs, int max_parsed,
 	 * callback. If the callback is not available, then we skip to the next
 	 * attribute; otherwise, we call the destroy() callback.
 	 */
-	for (i = 0; i < max_parsed; ++i) {
+	for (i = SEG6_LOCAL_SRH; i < max_parsed; ++i) {
 		if (!(parsed_attrs & SEG6_F_ATTR(i)))
 			continue;
 
@@ -1665,14 +1963,15 @@ static void destroy_attrs(struct seg6_local_lwt *slwt)
 }
 
 static int parse_nla_optional_attrs(struct nlattr **attrs,
-				    struct seg6_local_lwt *slwt)
+				    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 = 0; i < SEG6_LOCAL_MAX + 1; ++i) {
+	for (i = SEG6_LOCAL_SRH; i < SEG6_LOCAL_MAX + 1; ++i) {
 		if (!(desc->optattrs & SEG6_F_ATTR(i)) || !attrs[i])
 			continue;
 
@@ -1681,7 +1980,7 @@ static int parse_nla_optional_attrs(struct nlattr **attrs,
 		 */
 		param = &seg6_action_params[i];
 
-		err = param->parse(attrs, slwt);
+		err = param->parse(attrs, slwt, extack);
 		if (err < 0)
 			goto parse_optattrs_err;
 
@@ -1734,7 +2033,8 @@ static void seg6_local_lwtunnel_destroy_state(struct seg6_local_lwt *slwt)
 	ops->destroy_state(slwt);
 }
 
-static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *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;
@@ -1771,21 +2071,21 @@ static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 	}
 
 	/* parse the required attributes */
-	for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
+	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);
+			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);
+	err = parse_nla_optional_attrs(attrs, slwt, extack);
 	if (err < 0)
 		goto parse_attrs_err;
 
@@ -1829,7 +2129,7 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla,
 	slwt = seg6_local_lwtunnel(newts);
 	slwt->action = nla_get_u32(tb[SEG6_LOCAL_ACTION]);
 
-	err = parse_nla_action(tb, slwt);
+	err = parse_nla_action(tb, slwt, extack);
 	if (err < 0)
 		goto out_free;
 
@@ -1876,7 +2176,7 @@ static int seg6_local_fill_encap(struct sk_buff *skb,
 
 	attrs = slwt->desc->attrs | slwt->parsed_optattrs;
 
-	for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
+	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);
@@ -1933,6 +2233,9 @@ static int seg6_local_get_encap_size(struct lwtunnel_state *lwt)
 			  /* 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;
 }
 
@@ -1956,7 +2259,7 @@ static int seg6_local_cmp_encap(struct lwtunnel_state *a,
 	if (attrs_a != attrs_b)
 		return 1;
 
-	for (i = 0; i < SEG6_LOCAL_MAX + 1; i++) {
+	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))
@@ -1988,6 +2291,15 @@ int __init seg6_local_init(void)
 	 */
 	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);
 }