On Wed, Apr 26, 2017 at 1:07 PM, Craig Gallek <kraigatg...@gmail.com> wrote:
> From: Craig Gallek <kr...@google.com>
>
> The IPv6 tunneling code tries to insert IPV6_TLV_TNL_ENCAP_LIMIT and
> IPV6_TLV_PADN options when an encapsulation limit is defined (the
> default is a limit of 4). An MTU adjustment is done to account for
> these options as well. However, the options are never present in the
> generated packets.
>
> ipv6_push_nfrag_opts requires that IPV6_RTHDR be present in order to
> include any IPV6_DSTOPTS options. The v6 tunnel code does not
> use routing options, so the encap limit options are not included.
>
> A brief reading of RFC 3542 section 9.2 (specifically the 4th paragraph)
> makes me believe that this requirement in the kernel is incorrect.
Looking more closely, I think I'm wrong here. Specifically, the cmsg
parser puts IPV6_RTHDRDSTOPTS in dst0opt and IPV6_DSTOPTS in dst1opt.
The tunnel code is currently building dst0opt and using
ipv6_push_nfrag_opts. Perhaps it should be building dst1opt and
calling ipv6_push_frag_opts?
