Can you show me the range match P4 and its controller example

[Nano5e]

There seem to be bugs when attempting to add range match entries to tables. Specifically, I have been unable to successfully add such entries via controller.py , as the range match never seems to hit.

[edgar-costa]

Hi @Nano5e

Can you show me how do you add it? Also, can you look at the switch logs and dump the table entries after you added it?

[Nano5e]

Sorry for not being able to get back to you in time.

A demo based on MPLS

I implement a demo based on MPLS to test range match in P4 language. but I fail, it seems that I can't add range match entries to the table via runtime_api.

main files:

network.py : Building the network
basic.p4 : p4 file for switches other than s4
basic_digest.p4 : p4 file for switch s4, peform packet counting and sending count numbers to control plane.
controller.py : runtime_api add entries to tables.
controller_get_digest.py : get the number send to control plane.

Some details

mac_learn counts packets coming into s4 and sends them to the control plane via digest. The counter is cleared every 15 counts. mac_learn and smac table is in basic_digest.p4:

key = {                             
standard_metadata.ingress_port : range;                         
 }                       
actions = {                              
mac_learn;                              
NoAction;                          
}                      
size =256;                      
default_action = NoAction;           
} 

There are four ports: 1,2,3,4. Incoming packets are counted on every port of s4 switch. (This can be accomplished using exact match, but I want to test range match.)
I added range match entry to smac table via p4runtime_API in controller.py

controller.table_add('smac','mac_learn', ['0x0001..0x0004']) 

However, this does not work.

However if I add const entries in P4 file (basic_digest.p4)

table smac {         
    key = {            
        standard_metadata.ingress_port : range;         
       }
   actions = {                      
mac_learn;                     
 NoAction;                  
}              
size =256;              
default_action = NoAction;       
const entries = {                      0x0001..0x0004 : mac_learn();                  }          
} 

It works.

[edgar-costa]

Hi,

Sorry for the very late reply. I did not see this.

This is how the range entries are parsed:
https://github.com/nsg-ethz/p4-utils/blob/master/p4utils/utils/thrift_API.py#L639C28-L639C50

That means you have to do it as "start->end".

you could have checked the CLI output logs, probably it complained with the following message:

"Invalid range value {}, use '->' to separate range start "
                    "and range end"