Re: Howto use agr to aggregate VPN tunnels

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Mon, Dec 19, 2016 at 10:08:29PM +0100, BERTRAND jo??l wrote:
> 
> If I try to sent ICMP packets over agr0, bad checksums counter goes up :
> 
> 28 packets transmitted, 0 packets received, 100.0% packet loss
> einstein# netstat -s | grep bad
>         ...
>         32 bad checksums
> 	...
> 
> 	I suppose packets are not transfered from agr0 to tap0/1 as checksum are
> false.

That's interesting -- they're probably zero or uninitialized.  The question
is, why?  There have been a number of bugs like this over the years, but since
agr works with real Ethernet interfaces...

Actually, I wonder if anyone has agr working with an Ethernet interface that
does _not_ have checksum offload support.  We did a bunch of work at CP to be
sure that checksum offloading would work properly with vlan stacked on agr
stacked on... and we would definitely have tested with checksum offload
_disabled_ in the physical interface at the bottom, but possibly not with an
interface that didn't announce the capability at all -- maybe there's a call
to in_delayed_cksum() missing somewhere?

Thor