On 3 Nov 2012, at 14:19, Arran Cudbard-Bell <a.cudbardb@freeradius.org> wrote:
On 3 Nov 2012, at 12:31, Bjørn Mork <bjorn@mork.no> wrote:
Arran Cudbard-Bell <a.cudbardb@freeradius.org> writes:
There's also a new xlat expansion %{dhcp_options:}. Some switch vendors offer DHCP to RADIUS gateways, but don't define their own VSAs to represent DHCP options, so include the DHCP options from the DHCP packet as an opaque blob of binary data packed into a single VSA.
Seeing as the server already has the code to parse dhcp options, it seemed like a fun hack to expose it as an xlat function. %{dhcp_options:} takes an attribute reference with qualifiers, and expands to the number of options in the blob. During expansion it adds all the options it finds in the blob to the request list with +=, using the FR DHCP dictionary.
If anyone knows of other vendors besides the lazy lazy French one doing this, please let me know.
I'm not sure what you are referring to here, but if I understand this feature correctly then I believe it will be useful with Juniper JUNOS and JUNOSe access routers as well. Newer versions decode some of the more useful DHCP options and provide them in separate attributes, but the raw list of all DHCP options is also available. E.g:
ERX-Dhcp-Options = "5\001\0012\004\224z\247\0057\0103:;\001y\003!\006R'\001\033DSA13FBU atm 1/1/01/23:8.35\002\01067676775"
I assume this is what the new xlat will decode? That is very useful.
Yes. Though it looks like ERX-Dhcp-Options is defined wrongly as a string in the vendor's dictionary, i'll go fix that...
Heh. So it works as is, with no additional hacks. update request { Tmp-Octets-0 := "0x3501013204947aa7053708333a3b01790321065227011b44534131334642552061746d20312f312f30312f32333a382e333502083637363736373735" } update request { Tmp-Integer-0 := "%{dhcp_options:Tmp-Octets-0}" } update request { Tmp-String-0 := "%{string:DHCP-Relay-Circuit-Id}" Tmp-String-1 := "%{string:DHCP-Relay-Remote-ID}" } (0) update request { DHCP-Message-Type += DHCP-Discover DHCP-Requested-IP-Address += 148.x.x.x (removed because i'm nice :) ) DHCP-Parameter-Request-List += DHCP-IP-Address-Lease-Time DHCP-Parameter-Request-List += DHCP-Renewal-Time DHCP-Parameter-Request-List += DHCP-Rebinding-Time DHCP-Parameter-Request-List += DHCP-Subnet-Mask DHCP-Parameter-Request-List += DHCP-Classless-Static-Route DHCP-Parameter-Request-List += DHCP-Router-Address DHCP-Parameter-Request-List += DHCP-Static-Routes DHCP-Parameter-Request-List += DHCP-Domain-Name-Server DHCP-Relay-Circuit-Id = 0x44534131334642552061746d20312f312f30312f32333a382e3335 DHCP-Relay-Remote-Id = 0x3637363736373735 (0) expand: %{dhcp_options:Tmp-Octets-0} -> 12 (0) } # update request = notfound (0) update request { (0) expand: %{string:DHCP-Relay-Circuit-Id} -> DSA13FBU atm 1/1/01/23:8.35 (0) expand: %{string:DHCP-Relay-Remote-ID} -> 67676775 (0) } # update request = notfound Sweet :) -Arran