[Kea-users] Selecting subnet based on circuit-id (INTERNAL)

Wed Dec 15 15:03:16 UTC 2021

I missed the question for using the identifier, 

So my full identification looks like this, 

	"library": "/usr/local/lib/kea/hooks/libdhcp_flex_id.so",
        "parameters": {
        	"identifier-expression": "ifelse(substring(option[60].hex,0,18) == 'HT8XX dslforum.org' or substring(option[60].hex,0,18) == 'HT802 dslforum.org' or substring(option[60].hex,0,18) == 'HT812 dslforum.org','GSATA/' + relay4[1].hex,relay4[1].hex)",
        	"replace-client-id": true
         }

If the connected device is a GrandStream device I select a different subnet from my shared subnets. Like this:

    "client-classes": [
        {
            "name": "GS-ATA",
            "test" : "substring(option[60].hex,0,18) == 'HT8XX dslforum.org' or substring(option[60].hex,0,18) == 'HT802 dslforum.org' or substring(option[60].hex,0,18) == 'HT812 dslforum.org'",
            "option-data": [{"name": "tftp-server-name", "data": "https://portal.m33access.com/GS"}]
        },
	{
            "name": "GPON-DHCP",
            "test" : "not member(‘GS-ATA')"
        }
    ],

The last set in the Circuit ID should be the VLAN, So in your case you should be able to pull the last 4 digits and test for it. 

In my subnets: (global IPs changed for privates) 

    "shared-networks": [
    {
    "name": "GPONNorth",
    "interface": "ens224",
        "subnet4": [
            {
            "subnet": "172.16.134.0/23",
            "id": 1,
            "pools": [ { "pool": "172.16.134.3 - 172.16.135.250" } ],
            "option-data": [{"name": "routers", "data": "172.16.134.1"}],
            "client-class": "GS-ATA"
            },
            {
            "subnet": “10.0.0.0/24",
            "id": 2,
            "pools": [ { "pool": “10.0.0.2 - 10.0.0.254” } ],
            "option-data": [{"name": "routers", "data": “10.0.0.1"}],
            "client-class": "GPON-DHCP"
            },

	]
    },
    {
    "name": "GPONWest",
    "interface": "ens192",
        "subnet4": [
            {
            "subnet": “10.0.1.0/24",
            "id" : 4,
            "pools": [ { "pool": “10.0.1.2 - 10.0.1.254" } ],
            "option-data": [{"name": "routers", "data": “10.0.0.1"}],
            "client-class": "GPON-DHCP"
            },
            {
            "subnet": "172.16.136.0/23",
            "id": 5,
            "pools": [ { "pool": "172.16.136.10 - 172.16.137.250" } ],
            "option-data": [{"name": "routers", "data": "172.16.136.1"}],
            "client-class": "GS-ATA"
            }
	]
    },
],

My classification is based on the vendor name, Then I use the “interface” command to specify my VLANs.. Since the traffic is already separated, I just set up my box with each VLAN as a separate interface. 

I hope this helps

- Allan

> On Dec 15, 2021, at 8:17 AM, Weisteen Per <per.weisteen at telenor.no> wrote:
> 
> I believe ISC has released the flex hook for KEA 2.0 in the standard package. At least the flex library is part of the installation under /usr/lib64/kea/hooks/
> 
> And defining the library seems to give no error messages.
> 
>           "library": "/usr/lib64/kea/hooks/libdhcp_flex_option.so",
>           "parameters": {
>               "identifier-expression": "relay4[2].hex"
>           }
> 
> Do I need to define circuit-id here under parameters?
> 
> My challenge is also how to use circuit-id identifier correctly in a test under client-classes.
> 
> 
> ./PerW
> 
> 
> -----Original Message-----
> From: Allan M33 Access <allan at m33access.com> 
> Sent: onsdag 15. desember 2021 12:47
> To: Weisteen Per <per.weisteen at telenor.no>
> Cc: kea-users at lists.isc.org
> Subject: Re: [Kea-users] Selecting subnet based on circuit-id (OPEN)
> 
> The flexible identifier hook for kea will allow you to use the dhcp option 82 sub option 1 as an identifier for leases. The flex hook is part of the premium hook packages though, purchasable on Isc’s website. The package also comes with the legal logging hook. 
> 
> My setup has the same concept, for my VLANs I set them up as individual interfaces on my box, then I define those interfaces for each subnet in the configuration. I use the flex it to use the circuit id as an identifier with “replace-client-id”: true
> 
> Even though the circuit id does have the VLAN in it, I choose subnets by the interface the packet comes in on instead.
> 
> -Allan
> 
>> On Dec 15, 2021, at 5:12 AM, Weisteen Per <per.weisteen at telenor.no> wrote:
>> 
>> Hi
>> 
>> I've just set up KEA 2.0 on a RHEL 8 box using RedHat Repository setup as instructed at cloudsmith.io. 
>> Seems that the packages available for me now is kea.x86_64, kea-devel.x86_64, kea-hooks.x86_64 and kea-libs.x86_64 all of which I have installed.
>> 
>> Seems though I'm missing some libraries mentioned in the kea-dhcp4.conf file like libdhcp_legal_log.so and control-agent-commands.so but I assume they're not critical.
>> 
>> What I initially need is to be able to select beween subnets based on which VLAN/VPN the request comes from. My network guys has set up several Cisco routers which will assign clients to one specific VLAN/VPN if the client manages to authenticate using 802.1x and to another if the authentication fails. Am I correct to believe that Cisco router will supply me with information on which VLAN/VPN a client was assigned to using circuit-id?  Is this a parameter already predefined in KEA or do I have to define it somewhere?
>> 
>> Thanks,
>> 
>> 
>> ./PerW
>> 
>> 
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