ip6m_mtu 30 include/uapi/linux/ipv6.h __u32 ip6m_mtu; ip6m_mtu 383 net/ipv6/datagram.c mtu_info->ip6m_mtu = mtu; ip6m_mtu 1230 net/ipv6/ipv6_sockglue.c mtuinfo.ip6m_mtu = dst_mtu(dst); ip6m_mtu 1232 net/ipv6/ipv6_sockglue.c if (!mtuinfo.ip6m_mtu)