Re: ROUTE_MPATH and hashing

From: Alexander V. Chernikov <melifaro_at_ipfw.ru>
Date: Mon, 20 Sep 2021 23:06:50 UTC 
> On 17 Sep 2021, at 01:36, Mark Kamichoff <prox@prolixium.com> wrote:
> 
> Hi - 
> 
Hi Mark,
> Does anyone here know how to tweak the hashing algorithm (per flow/packet/x)
> that's used for the new ROUTE_MPATH option that's in 13?
> 
> I'm using FRR 7 and I see both routes in the FIB but only one is ever
> chosen and takes traffic.
Is it IPv6 forwarding or the packets are originated locally?
In case of former, what is the receive interface? (e.g. is it tun as well)?
> 
> (dax:20:23:EDT)% show ipv6 route 2620:6:2003:105::/64  
> Routing entry for 2620:6:2003:105::/64
>  Known via "bgp", distance 20, metric 0, best
>  Last update 08:24:34 ago
>    2620:6:2000:104::35 (recursive), weight 1
>  *   2620:6:2000:1ff::10c2, via tun9, weight 1
>  *   2620:6:2000:1ff::1172, via tun12, weight 1
> 
> (dax:20:23:EDT)% netstat -rn|grep 2620:6:2003:105::/64
> 2620:6:2003:105::/64              2620:6:2000:1ff::1172         UG1       tun12
> 2620:6:2003:105::/64              2620:6:2000:1ff::10c2         UG1        tun9
> (dax:20:23:EDT)% route -n6 get 2620:6:2003:105::     
>   route to: 2620:6:2003:105::
> destination: 2620:6:2003:105::
>       mask: ffff:ffff:ffff:ffff::
>    gateway: 2620:6:2000:1ff::1172
>        fib: 0
>  interface: tun12
>      flags: <UP,GATEWAY,DONE,PROTO1>
> recvpipe  sendpipe  ssthresh  rtt,msec    mtu        weight    expire
>       0         0         0         0      1455         0         0 
> (dax:20:23:EDT)%
> 
> I didn't see any sysctls exposed but maybe I'm not looking in the right
> place.
> 
> - Mark
> 
> -- 
> Mark Kamichoff
> prox@prolixium.com
> https://www.prolixium.com/
>