Rare project developers

[mc36 <>]

hi,
excellent questions... let me start from the easiest to the hardest:
-freerouter starts an sdn interface in up when you issue "int sdn1"
-for this experiment, "int sdn1" / "log-link" should be configured btw... :)
-upon exporting under "server p4lang", it get's it's underlay so it goes down
-as long as the forwarder reports a state from the dataplane...
-to see the above, debug serv p4 rx/tx should be enabled too...
now the part i clearly not understand is
" After a warm reload, it still briefly works, but then sdn1 changes state to down 
and never comes back up."
because freerouter reports N if an interface is down and no other route 
exists...
thanks,
cs



On 6/14/22 08:24, Alexander Gall wrote:
> Hi
>
> I'm reproducing the demo I've made running the RARE release on the
> Tofino model and some questions popped up.
>
> For now, I'm still using the built-in JSON ports file with the veths,
> i.e. veth0 is connected to Tofino port #0 etc.
>
> Baically, what I'm doing is add an interface sdn1 on frontpanel-1/0,
> configure an address on it and on veth1 and do a ping. It works, but
> I'm actually confused why it works :/
>
> The thing is that I've realized for the first time that the OPR
> status of the Tofino ports in the model is always DWN, e.g.
>
> bf-sde.pm> show -p 1/0
> -----+----+---+----+-------+----+--+--+---+---+---+--------+----------------+----------------+-
> PORT |MAC |D_P|P/PT|SPEED  |FEC |AN|KR|RDY|ADM|OPR|LPBK    |FRAMES RX |FRAMES 
> TX       |E
> -----+----+---+----+-------+----+--+--+---+---+---+--------+----------------+----------------+-
> 1/0  |15/0|  0|0/ 0|10G    |NONE|Ds|Au|YES|ENB|DWN|  NONE  | 8|              
> 10|*
>
> This is despite the model logging
>
> :06-14 08:07:26.582773:    PORT UP asic 0 port 0
>
> AFAICT, this is happening at least for SDE 9.6.x through 9.7.x. For SDE
> 9.8.0 and 9.9.0, the OPR status is reported as UP when a port is
> connected to it via the JSON port mapping. Can you confirm this?
>
> The model seems to ignore the OPR status and forwards packets in both
> direction. What confuses me with freerouter is that the port is
> reported to be up anyway right after adding the config for sdn1
>
> rare(cfg)#vrf definition foo
> rare(cfg-vrf)#exit
> rare(cfg)#interface sdn1
> rare(cfg-if)#vrf forwarding foo
> rare(cfg-if)#ipv4 address 192.168.1.1 /24
> rare(cfg-if)#exit
> rare(cfg)#server p4lang p4
> rare(cfg-server)#export-port sdn1 frontpanel-1/0 10 2 1 0
> rare(cfg-server)#export-vrf foo 2
> rare(cfg-server)#sh int sdn1
> sdn1 is up
>   description:
>   state changed 3 times, last at 2022-06-14 08:14:27, 00:00:23 ago
>   last packet input never ago, output never ago, drop never ago
>   type is sdn, hwaddr=004b.4853.5536, mtu=1500, bw=8000kbps, vrf=foo
>   ipv4 address=192.168.1.1/24, mask=255.255.255.0, ifcid=545466702
>   received 0 packets (0 bytes) dropped 0 packets (0 bytes)
>   transmitted 0 packets (0 bytes) macsec=false sgt=false
>
> And ping works
>
> rare(cfg)#exit
> rare#ping 192.168.1.2 vrf foo
> pinging 192.168.1.2, src=null, vrf=foo, cnt=5, len=64, tim=1000,
> gap=0, ttl=255, tos=0, sgt=0, flow=0, fill=0, sweep=false, multi=false
> .!!!!
> result=80%, recv/sent/lost/err=4/5/1/0, rtt
> min/avg/max/sum=16/252/956/2037, ttl min/avg/max=64/64/64, tos
> min/avg/max=0/0/0
>
> After a warm reload, it still briefly works, but then sdn1 changes
> state to down and never comes back up.
>
> So my questions are
>
>     * Is this a bug in the Tofino model up to 9.7?
>     * Why does freerouter (sort of) still work (i.e. ignoring the
>       actual oper status)?