Re: [lwip-devel] IPv6: Ensuring Router Advertisements and SLAAC Work

[Ivan Delamer]

Hi Grant,

The link-local all-nodes address is automatically subscribed to, but I
don't remember if a call to mld_mac_filter is made or not.

If not, please add it as a bug so that it is not forgotten, I'll fix it
when I return from holidays in a couple weeks.

Cheers
Ivan


On Thu, December 27, 2012 16:48, Grant Erickson wrote:
> Ivan,
>
> More progress on IPv6 to report. I added the following to my
> initialization function:
>
>       @@ -145,7 +180,20 @@ static void host_hardware_init(struct netif *netif)
>        #endif
>        #if LWIP_IPV6 && LWIP_IPV6_MLD
>            netif->mld_mac_filter = host_mld_mac_filter;
>       -#endif
>       +#if LWIP_IPV6_AUTOCONFIG
>       +    // Ensure that any interface supporting IPv6 is subscribed to the
>       +    // link-local all-nodes address (ff02::1) such that it picks up
>       +    // router advertisements for stateless address auto-configuration
>       +    // (SLAAC).
>       +    {
>       +        ip6_addr_t allnodes_linklocal;
>       +
>       +        ip6_addr_set_allnodes_linklocal(&allnodes_linklocal);
>       +
>       +        host_mld_mac_filter(netif, &allnodes_linklocal,
> MLD6_ADD_MAC_FILTER);
>       +    }
>       +#endif // LWIP_IPV6_AUTOCONFIG
>       +#endif // LWIP_IPV6 && LWIP_IPV6_MLD
>
> and I now correctly receive a SLAAC address based on router
> advertisements:
>
>       > ip addr show
>       1: en0: <BROADCAST,UP,LOWER_UP,> mtu 1536
>           link/ether 02:28:3e:3d:43:47 brd ff:ff:ff:ff:ff:ff
>           inet 10.2.1.28/16 brd 10.2.255.255 scope global en0
>           inet6 FE80::0228:3EFF:FE3D:4347/64 scope link
>           inet6 FDCB:6364:780D:D6A1:0228:3EFF:FE3D:4347/64 scope unique
>
> and can ping6 the address from Linux:
>
>       % ping6 -c 4 FDCB:6364:780D:D6A1:0228:3EFF:FE3D:4347
>       PING
> FDCB:6364:780D:D6A1:0228:3EFF:FE3D:4347(fdcb:6364:780d:d6a1:0228:3eff:fe3d:4347)
> 56 data bytes
>       64 bytes from fdcb:6364:780d:d6a1:0228:3eff:fe3d:4347: icmp_seq=1 
> ttl=255
> time=91.1 ms
>       64 bytes from fdcb:6364:780d:d6a1:0228:3eff:fe3d:4347: icmp_seq=2 
> ttl=255
> time=98.1 ms
>       64 bytes from fdcb:6364:780d:d6a1:0228:3eff:fe3d:4347: icmp_seq=3 
> ttl=255
> time=4.46 ms
>       64 bytes from fdcb:6364:780d:d6a1:0228:3eff:fe3d:4347: icmp_seq=4 
> ttl=255
> time=14.2 ms
>
>       --- FDCB:6364:780D:D6A1:0228:3EFF:FE3D:4347 ping statistics ---
>       4 packets transmitted, 4 received, 0% packet loss, time 3005ms
>       rtt min/avg/max/mdev = 4.467/51.981/98.148/42.855 ms
>
> and can ping6 Linux back:
>
>       > ping6 -c 4 fdcb:6364:780d:d6a1:20c:29ff:fe15:eeb8
>       PING fdcb:6364:780d:d6a1:20c:29ff:fe15:eeb8
> (FDCB:6364:780D:D6A1:20C:29FF:FE15:EEB8): 56(104) bytes of data
>       64 bytes from fdcb:6364:780d:d6a1:20c:29ff:fe15:eeb8
> (FDCB:6364:780D:D6A1:20C:29FF:FE15:EEB8): icmp_seq=1 ttl=64
>       64 bytes from fdcb:6364:780d:d6a1:20c:29ff:fe15:eeb8
> (FDCB:6364:780D:D6A1:20C:29FF:FE15:EEB8): icmp_seq=2 ttl=64
>       64 bytes from fdcb:6364:780d:d6a1:20c:29ff:fe15:eeb8
> (FDCB:6364:780D:D6A1:20C:29FF:FE15:EEB8): icmp_seq=3 ttl=64
>       64 bytes from fdcb:6364:780d:d6a1:20c:29ff:fe15:eeb8
> (FDCB:6364:780D:D6A1:20C:29FF:FE15:EEB8): icmp_seq=4 ttl=64
>
>       --- fdcb:6364:780d:d6a1:20c:29ff:fe15:eeb8 ping statistics ---
>       4 packets transmitted, 4 received, 0 duplicates, 0 errors 0% packet 
> loss,
> time 5054ms
>       round-trip min/avg/max = 0.000/1012.000/253.000 ms
>
> It seems as though the patched block above should be within the IPv6 core
> stack of LwIP itself rather than being in the platform support glue, much
> as I'd argue for the netif_create_ip6_linklocal_address() call following
> netif_add().
>
> Setting LWIP_IPV6_AUTOCONFIG clearly isn't enough to get SLAAC working. At
> minimum:
>
>       1) The above diff
>       2) The below diff:
>
>               +#if LWIP_IPV6
>               +    // Establish an IPv6 link-local address
>               +
>               +    netif_create_ip6_linklocal_address(&my_if, 1);
>               +#if LWIP_IPV6_AUTOCONFIG
>               +    my_if.ip6_autoconfig_enabled = 1;
>               +#endif
>               +#endif
>
>          after netif_add().
>
> are required.