fwd: host config file based on vendor specific options and service level

[David W. Hankins]

On Fri, Apr 07, 2006 at 03:04:11PM +0200, roger murray wrote:
>  ex. host declarations before change:
> 
>  host A-1-001 {
>          filename "service_A";
>          hardware ethernet aa:bb:cc:dd:ee:ef;
>          fixed-address 10.xx.yy.yz;
>  }
> 
>  host B-1-001 {
>          filename "service_B";
> 
>          hardware ethernet aa:bb:cc:dd:ee:ff;
>          fixed-address 10.xx.yy.zz;
>  }
> 
> 
>  host A-1-001 {
> 
>          if (substring (option Vendor.model, 0, 6) = "Model_1") {
>                  filename "config_file_Model_1_service_A";
> 
>          } elsif (substring (option Vendor.model, 0, 6) = "Model_2") {
>                  filename "config_file_Model_2_service_A";
>          } elsif (substring (option Vendor.model, 0, 6) = "Model_3") {
>                  filename "config_file_Model_3_service_A";
>          } elsif (substring (option Vendor.model, 0, 6) = "Model_4") {
>                  filename "config_file_Model_4_service_A";
>          } else {
>                  filename "config_file_catch_all";
>          }
>          hardware ethernet aa:bb:cc:dd:ee:ef;
>          fixed-address 10.xx.yy.yz;
>  }
> 
>  host B-117-001 {
> 
>          if (substring (option Vendor.model, 0, 6) = "Model_1") {
>                  filename "config_file_Model_1_service_B";
> 
>          } elsif (substring (option Vendor.model, 0, 6) = "Model_2") {
>                  filename "config_file_Model_2_service_B";
>          } elsif (substring (option Vendor.model, 0, 6) = "Model_3") {
>                  filename "config_file_Model_3_service_B";
>          } elsif (substring (option Vendor.model, 0, 6) = "Model_4") {
>                  filename "config_file_Model_4_service_B";
>          } else {
>                  filename "config_file_catch_all";
> 
>          }
>          hardware ethernet aa:bb:cc:dd:ee:ff;
>          fixed-address 10.xx.yy.zz;
>  }

Wow.

I know why that takes so long to load...it's a /lot/ of small memory
allocations to fill out all those executable statements for the if/else
chains.

May I suggest:

class "BootModels" {
	match substring(option Vendor.model, 0, 6);
}

subclass "BootModels" "Model_1" { set pathprefix = "Model_1"; }
subclass "BootModels" "Model_2" { set pathprefix = "Model_2"; }
subclass "BootModels" "Model_3" { set pathprefix = "Model_3"; }
subclass "BootModels" "Model_4" { set pathprefix = "Model_4"; }

# Note: if Vendor.model substring really is "Model_4" and identical to
# what we're setting pathprefix to, you could just using that directly.

class "BootServices" {
	match hardware;
}

subclass "BootServices" aa:bb:cc:dd:ee:ff { set pathsuffix = "A"; }
subclass "BootServices" gg:hh:ii:jj:kk:ll { set pathsuffix = "B"; }

filename = concat("config_file_", pathprefix, "_service_", pathsuffix);
#filename = concat("config_file_", substring(option Vendor.model, 0, 6),
#		   "_service_", pathsuffix);

host A-1-001 {
	hardware ethernet yadda..;
	fixed-address yadda;
}

host B-1-001 {
	hardware ethernet yadda...;
	fixed-address yadda;
}


Some ideas to play around with if you haven't already, anyway.

I don't know if that actually works.  Binding scopes are a weird thing
to use for a static lease (they're meant to survive on dynamic lease
states in dhcpd.leases).

-- 
David W. Hankins		"If you don't do it right the first time,
Software Engineer			you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins