lwIP正在加入IPv6，一个实验性的版本可以通过git下载，该版本实现了一个IPv4/IPv6的双协议栈。通过在lwipopts.h定义LWIP_IPV6可以使能IPv6
2.已实现的IPV6协议
- IPv6 layer, parallel to IPv4
- Support in TCP/UDP/RAW pcbs
- Support in Netconn API
- Support in Socket API
- ICMPv6
- Neighbor Discovery
- Multicast Listener Discovery
- Stateless address autoconfiguration
- IPv6 fragmentation and reassembly
- Ethernet IF using ND
IPv6 addresses are specified using the ip6_addr_t define in ip6_addr.h.