[net-next v8 03/10] ipv6: Add case for IPV6_TLV_TNL_ENCAP_LIMIT in EH TLV switch

[Tom Herbert <tom@herbertland.com>]

IPV6_TLV_TNL_ENCAP_LIMIT is a recognized Destination option that is
processed in ip6_tunnel.c. Add a case for it in the switch in
ip6_parse_tlv so that it is recognized as a known option.

Also remove the unlikely around the check for max_count < 0 since the
default limits for HBH and Destination options can be less than zero.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Reviewed-by: Justin Iurman <justin.iurman@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
---
 net/ipv6/exthdrs.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 113efbc19abe..e61d97621108 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -122,7 +122,7 @@ static bool ip6_parse_tlv(bool hopbyhop,
 	int tlv_count = 0;
 	int padlen = 0;
 
-	if (unlikely(max_count < 0)) {
+	if (max_count < 0) {
 		disallow_unknowns = true;
 		max_count = -max_count;
 	}
@@ -202,6 +202,16 @@ static bool ip6_parse_tlv(bool hopbyhop,
 					if (!ipv6_dest_hao(skb, off))
 						return false;
 					break;
+#endif
+#if IS_ENABLED(CONFIG_IPV6_TUNNEL)
+				case IPV6_TLV_TNL_ENCAP_LIMIT:
+					/* The tunnel encapsulation option.
+					 * This is handled in ip6_tunnel.c so
+					 * we don't need to do anything here
+					 * except to accept it as a recognized
+					 * option
+					 */
+					break;
 #endif
 				default:
 					if (!ip6_tlvopt_unknown(skb, off,
-- 
2.43.0