Route export problem with FreeBSD 13.0

[Alexander V. Chernikov]

> On 28 Aug 2021, at 15:23, Luiz Amaral <email at luiz.eng.br> wrote:
> 
> Hello guys,
Hi Luiz,

> 
> After upgrading one of my hosts from FreeBSD 12.2 to FreeBSD 13.0, I
> started noticing a problem when exporting routes to the KRT.
Unfortunately, there were a number of issues in 13.0 w.r.t rtsock handling.
I’d suggest considering updating to 13-STABLE.
> 
> My logs were getting flooded with "kernel: gw sdl_len too small". This
> message comes from cleanup_xaddrs_gateway() in sys/net/rtsock.c of
> releng/13.0, so I checked with "route monitor" and noticed that the
> blackhole routes and one interface route were the ones causing the message.
> 
> got message of size 192 on Sat Aug 28 15:57:32 2021
> RTM_ADD: Add Route: len 192, pid: 2293, seq 3, errno 22,
> flags:<UP,BLACKHOLE,PROTO1>
> locks:  inits:
> sockaddrs: <DST,GATEWAY,NETMASK>
>  10.0.0.0 link#4 255.0.0.0
> 
> got message of size 192 on Sat Aug 28 15:57:32 2021
> RTM_ADD: Add Route: len 192, pid: 2293, seq 4, errno 22, flags:<UP,PROTO1>
> locks:  inits:
> sockaddrs: <DST,GATEWAY,NETMASK>
>  10.42.10.0 link#5 255.255.255.0
> 
> In BIRD they look the same as before the upgrade:
> 
> bird> show route all 10.0.0.0/8
> Table master4:
> 10.0.0.0/8           blackhole [s_null_4 2021-08-28 15:57:32] ! (200)
>         Type: static univ
> bird> show route all 10.42.10.0/24
> Table master4:
> 10.42.10.0/24        unicast [direct1 2021-08-28 16:07:59] ! (240)
>         dev vlan10
>         Type: device univ
> 
> 
> I then decided to try manually adding a blackhole route using "route add
> -net 10.0.0.0/8 -blackhole -proto1 -nostatic", to get as close to what
> BIRD was trying to add and noticed that BIRD had a gateway, but "route
> add" didn't have one.
> 
> got message of size 184 on Sat Aug 28 16:05:43 2021
> RTM_ADD: Add Route: len 184, pid: 2766, seq 1, errno 0,
> flags:<UP,GATEWAY,DONE,BLACKHOLE,PROTO1>
> locks:  inits:
> sockaddrs: <DST,NETMASK>
>  10.0.0.0 255.0.0.0
> 
> I tried commenting out line 324 in sysdep/bsd/krt-sock.c of v2.0.8 to
> see if that could fix it and bird was able to insert the blackhole route
> (can be seen below), but then bird started dying a couple seconds after
> starting up, with no error showing up on the logs.
> 
> got message of size 184 on Sat Aug 28 15:27:33 2021
> RTM_ADD: Add Route: len 184, pid: 46425, seq 2, errno 22, flags:<UP,PROTO1>
> locks:  inits:
> sockaddrs: <DST,NETMASK>
>  10.42.10.0 255.255.255.0
> 
> got message of size 184 on Sat Aug 28 15:27:33 2021
> RTM_ADD: Add Route: len 184, pid: 46425, seq 3, errno 0,
> flags:<UP,GATEWAY,DONE,BLACKHOLE,PROTO1>
> locks:  inits:
> sockaddrs: <DST,NETMASK>
>  10.0.0.0 255.0.0.0
> 
> 
> At this point, I ran out of ideas on what else to try. This is in a
> testing environment, so I can easily try things out or provide extra
> information.
> 
> Thank you,
> Luiz
> 
> 
>