[Kea-users] Globally cut circuit id option

[perl-list]

You can use substring to do that.  Here is an example of it in use:

match if substring (option dhcp-client-identifier, 1, 3) = "RAS";

see also `man dhcp-eval`

substring (data-expr, offset, length)

         The substring operator evaluates the data expression and returns the substring of the result of that evaluation that starts offset bytes from
         the  beginning,  continuing  for  length  bytes.  Offset and length are both numeric expressions.  If data-expr, offset or length evaluate to
         null, then the result is also null.  If offset is greater than or equal to the length of the evaluated data, then a zero-length  data  string
         is  returned.  If length is greater then the remaining length of the evaluated data after offset, then a data string containing all data from
         offset to the end of the evaluated data is returned.

----- Original Message -----
> From: "egor grijuc" <egor.grijuc at orange.com>
> To: "kea-users" <kea-users at lists.isc.org>
> Sent: Wednesday, January 26, 2022 4:40:26 AM
> Subject: [Kea-users] Globally cut circuit id option

> Hello.

> We faced a problem with some old equipment.

> We use host database for host reservation

> We make reservation via API.

> In table “host” we use dhcp_identifier_type =2 to match circuit id.

> It works but we have some old equipment that adds some kind of prefix to circuit
> id option.

> For example, on switch circuit id was configured to “CHN540579” but on packet
> capture we see that switch adds some “prefix”

> Part from capture:

> Agent-Information Option 82, length 23:

> Circuit-ID SubOption 1, length 11: ^A^ICHN540579

> Question: is it possible to globally cut circuit id optin from end to 9
> characters?
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