In article [ref] (at Tue, 26 Oct 2004 14:09:29 -0400), Brian Haley [off-list ref] says:

quoted

Second, because we're not ready to migrate.
Please do not do that (pushing it to the glibc people) until we're ready.
We really need to do in consistent way; kernel header / glibc header,
and even with other systems.

The kernel struct is the correct size (since addr[0] has no size), 
ip6_rthdr0 in ip6.h is not, it's 128 bits too big.  Let me know the 
right steps to go through to correct this and I'll get it done, you can 
send it off-line if you like.

Because we do not support RFC3542, extra 128bits is definitely correct.

--yoshfuji