[Kea-users] flex_id hook with multiple expressions

[Andreas]

Dear list,

we are trying to match multiple combinations of Agent Remote-ID and 
Circuit-ID for host reservations with the flex_id hook.

This is meant to match end customers over a whole bunch of solutions and 
hardware platforms where we can’t streamline the available DHCP options 
to one common expression.


Possible Remote-ID/Circuit-ID combinations:

  1)
Remote-ID: 58:ac:78:cf:3a:c0
Circuit-ID: 01:9f:02:17
Concatenated String for Host Reservations: 58:ac:78:cf:3a:c0:01:9f:02:17
"identifier-expression": "concat(relay4[2].hex,relay4[1].hex)"

2)
Remote-ID: NAME_DEU.LINED.0000012345
Circuit-ID: olt1.lhn-004:1-1-01-09-16.414
Concateanted String for Host Reservations: NAME_DEU.LINED.0000012345-414
"identifier-expression": "concat(concat(relay4[2].hex,'-'), 
substring(relay4[1].hex, -3, 3))"


We then tried several options to get that working with the 
„identifier-expression“ parameter:


Using „or“ to differentiate between the two possibilities according to 
https://kea.readthedocs.io/en/kea-3.0.1/arm/classify.html#classification-using-expressions

"identifier-expression": "concat(concat(relay4[2].hex,'-'), 
substring(relay4[1].hex, -3, 3)) or concat(relay4[2].hex,relay4[1].hex)"


by specifying multiple expression in separate lines:

"identifier-expression": "concat(concat(relay4[2].hex,'-'), 
substring(relay4[1].hex, -3, 3))“,

"identifier-expression": "concat(relay4[2].hex,relay4[1].hex)"


and then by adding the hook library two times:

{

"library": "/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_flex_id.so",

"parameters": {

"identifier-expression": "concat(relay4[2].hex,relay4[1].hex)"

}

},

{

"library": "/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_flex_id.so",

"parameters": {

"identifier-expression": "concat(concat(relay4[2].hex,'-'), 
substring(relay4[1].hex, -3, 3))“

}

},


For the last two possible solutions kea only used the last definition of 
the hook or the „identifier-expression" parameter. And for the first one 
it simply doesn’t match.

Are there any ways to specify multiple expressions to match with the 
flex_id hook?


Thanks in advance


BR

Andreas


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