IPV6_PKTINFO/recvfromto

[Alan DeKok]

Alexander Clouter wrote:
> Finally found the time to look into this, a clean v2.1.10 tree with the 
> following cherry-picks:
>  * e5c861665f00f1213036ba412b7092aac7159ad7 (contains bug)
>  * fa0851d9235f04ff0d4161fc6f842857ff8d52aa

  Thanks.

> The bug is fixed with the attached 0003-fix-recvpktinfo.patch, and then 
> IPv6 is actually enabled with 0004-enable-ipv6.patch.
> 
> For PKTINFO to work, Linux needs IPV6_RECVPKTINFO (or the legacy 
> IPV6_2292PKTINFO) passed to setsockopt, however when you jump into 
> sendmsg() cmsg->cmsg_type has to be IPV6_PKTINFO (or the legacy 
> IPV6_2292PKTINFO); this is broken in the commit do to all the 
> define/undef magic going on.  I think I have sanitised it correctly.

  OK.  My only consideration here is tha IPV6_PKTINFO is a standard:

http://tools.ietf.org/html/rfc3542

  and it's implemented on multiple operating systems.  The weird #ifdef
magic was an attempt to make it work on Linux, which has 3-4 variants,
and *at the same time*, work on other platforms.

  I'll take a look at it...

  Alan DeKok.