ipv6: sr: add rtnetlink functions for seg6local action parameters

This patch adds the necessary functions to parse, fill, and compare
seg6local rtnetlink attributes, for all defined action parameters.

- The SRH parameter defines an SRH to be inserted or encapsulated.
- The TABLE parameter defines the table to use for the route lookup of
  the next segment or the inner decapsulated packet.
- The NH4 parameter defines the IPv4 next-hop for an inner decapsulated
  IPv4 packet.
- The NH6 parameter defines the IPv6 next-hop for the next segment or
  for an inner decapsulated IPv6 packet
- The IIF parameter defines an ingress interface index.
- The OIF parameter defines an egress interface index.

Signed-off-by: David Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/seg6_local.c

@@ -104,6 +104,181 @@ static const struct nla_policy seg6_local_policy[SEG6_LOCAL_MAX + 1] = {
 	[SEG6_LOCAL_OIF]	= { .type = NLA_U32 },
 };
 
+static int parse_nla_srh(struct nlattr **attrs, struct seg6_local_lwt *slwt)
+{
+	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))
+		return -EINVAL;
+
+	slwt->srh = kmalloc(len, GFP_KERNEL);
+	if (!slwt->srh)
+		return -ENOMEM;
+
+	memcpy(slwt->srh, srh, len);
+
+	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 int parse_nla_table(struct nlattr **attrs, struct seg6_local_lwt *slwt)
+{
+	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 int parse_nla_nh4(struct nlattr **attrs, struct seg6_local_lwt *slwt)
+{
+	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)
+{
+	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)
+{
+	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)
+{
+	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;
+}
+
 struct seg6_action_param {
 	int (*parse)(struct nlattr **attrs, struct seg6_local_lwt *slwt);
 	int (*put)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
@@ -111,29 +286,29 @@ struct seg6_action_param {
 };
 
 static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
-	[SEG6_LOCAL_SRH]	= { .parse = NULL,
+	[SEG6_LOCAL_SRH]	= { .parse = parse_nla_srh,
-				    .put = NULL,
+				    .put = put_nla_srh,
-				    .cmp = NULL },
+				    .cmp = cmp_nla_srh },
 
-	[SEG6_LOCAL_TABLE]	= { .parse = NULL,
+	[SEG6_LOCAL_TABLE]	= { .parse = parse_nla_table,
-				    .put = NULL,
+				    .put = put_nla_table,
-				    .cmp = NULL },
+				    .cmp = cmp_nla_table },
 
-	[SEG6_LOCAL_NH4]	= { .parse = NULL,
+	[SEG6_LOCAL_NH4]	= { .parse = parse_nla_nh4,
-				    .put = NULL,
+				    .put = put_nla_nh4,
-				    .cmp = NULL },
+				    .cmp = cmp_nla_nh4 },
 
-	[SEG6_LOCAL_NH6]	= { .parse = NULL,
+	[SEG6_LOCAL_NH6]	= { .parse = parse_nla_nh6,
-				    .put = NULL,
+				    .put = put_nla_nh6,
-				    .cmp = NULL },
+				    .cmp = cmp_nla_nh6 },
 
-	[SEG6_LOCAL_IIF]	= { .parse = NULL,
+	[SEG6_LOCAL_IIF]	= { .parse = parse_nla_iif,
-				    .put = NULL,
+				    .put = put_nla_iif,
-				    .cmp = NULL },
+				    .cmp = cmp_nla_iif },
 
-	[SEG6_LOCAL_OIF]	= { .parse = NULL,
+	[SEG6_LOCAL_OIF]	= { .parse = parse_nla_oif,
-				    .put = NULL,
+				    .put = put_nla_oif,
-				    .cmp = NULL },
+				    .cmp = cmp_nla_oif },
 };
 
 static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)