Rare project developers

[Alexander Gall <>]

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)?

-- 
Alex