[lwip-devel] IPv6 Loopback Functional

[Grant Erickson]

With the patches at https://savannah.nongnu.org/patch/?7913, IPv6 loopback 
support is now functional:

        > ip addr show
        1: lo0: <UP> mtu 0
            link/ether  brd ff:ff:ff:ff:ff:ff
            inet 127.0.0.1/8 brd 127.255.255.255 scope global lo0
            inet6 ::1/128 scope host 

        > ping -c 4 127.0.0.1
        PING 127.0.0.1 (127.0.0.1): 56(84) bytes of data
        64 bytes from 127.0.0.1 (127.0.0.1): icmp_seq=1 ttl=255 time=1.000 ms
        64 bytes from 127.0.0.1 (127.0.0.1): icmp_seq=2 ttl=255 time=1.000 ms
        64 bytes from 127.0.0.1 (127.0.0.1): icmp_seq=3 ttl=255 time=1.000 ms
        64 bytes from 127.0.0.1 (127.0.0.1): icmp_seq=4 ttl=255 time=1.000 ms

        --- 127.0.0.1 ping statistics ---
        4 packets transmitted, 4 received, 0 duplicates, 0 errors 0% packet 
loss, time 4030ms
        round-trip min/avg/max = 1.000/1.000/1.000 ms

        > ping6 -c 4 ::1
        PING ::1 (::1): 56(104) bytes of data
        64 bytes from ::1 (::1): icmp_seq=1 ttl=255 time=1.000 ms
        64 bytes from ::1 (::1): icmp_seq=2 ttl=255 time=1.000 ms
        64 bytes from ::1 (::1): icmp_seq=3 ttl=255 time=1.000 ms
        64 bytes from ::1 (::1): icmp_seq=4 ttl=255 time=1.000 ms

        --- ::1 ping statistics ---
        4 packets transmitted, 4 received, 0 duplicates, 0 errors 0% packet 
loss, time 4028ms
        round-trip min/avg/max = 1.000/1.000/1.000 ms

PS: If only for presentation handling, it seems like the netif struct may need 
a:

        u8_t ip6_addr_prefixlen[LWIP_IPV6_NUM_ADDRESSES];

field so that prefix lengths can be properly assigned and associated to IPv6 
addresses.

Best,

Grant