userspace: return correct ipv6 header len.
The ipv6 header len might have extension header, but current
code simply returns fixed ipv6 header length 40-byte.
@@ -123,7 +123,7 @@ netdev_tnl_ip_extract_tnl_md(struct dp_packet *packet, struct flow_tnl *tnl,
tnl->ip_tos = ntohl(tc_flow) >> 20;
tnl->ip_ttl = ip6->ip6_hlim;
- *hlen += IPV6_HEADER_LEN;
+ *hlen += packet->l4_ofs - packet->l3_ofs;
} else {
VLOG_WARN_RL(&err_rl, "ipv4 packet has invalid version (%d)",
