Re: refactoring ip_output() and the L2 _output()

[Mihai Chelaru <chelaru%gmail.com@localhost>]

On 26/05/15 05:42, Ryota Ozaki wrote:
> Hi,
>
> The mail subject may recall someone an old thread:
> https://mail-index.netbsd.org/tech-net/2013/02/01/msg003847.html
>
> Yes, I'm taking over the task :)
>
>
> http://www.netbsd.org/~ozaki-r/refactor_l2_output.diff
>
> The patch is basically the same as dyoung's patch with some
> tweaks to make it work on -current; it gets rid of route
> lookups from L2 output routines such as ether_output
> and puts them between ip_output and L2 output routines.
>
> One known issue of the change is that it adds an mbuf flag
> to tell ether_output that mbuf is to be set MPLS ether
> type. I don't think it's the best way but I don't have
> another better approach for now.
>
> Any comments or suggestions are welcome.
>
> Thanks,
>    ozaki-r

Hi there,

I have some questions/observations:

* This cod is generic enough to be linked apart from ip_output.c Maybe 
it can be reused by other protocols as well ? (hint nd6_output)
* did this patch passed the current net tests ?

Now about MPLS:

* I'm kinda reluctant in using flags to describe protocol specifics, 
maybe should use a tag for now instead of flags even if this interface 
is slower ?
* I think flagging/tagging should also be used in mpls LSE - probably in 
send_frame.
* and also in ip6 output path. I'll try to find time this week to write 
some tests for ip6/mpls - but you can test using route.
* mpls/gre needs also to be hacked because it uses the same test (have 
to write a test for mpls+gre, too)



Thanks


--
Mihai