[U-Boot-Users] DHCP vendor or class ID option

[U-Boot-Users] DHCP vendor or class ID option

[Jeffrey Mann]

U-boot users:

I have been searching the list and reading source code trying to
figure out if something that acomplishes vendor class ids or user
class ids has been implemented in u-boot's dhcp services. (microsoft
has a few articles that discuss uses of class IDS.
http://support.microsoft.com/kb/266675)

What I am trying to acomplish is this: I would like to be able to set
slightly different DHCP options when the DHCP request comes from a
board running u-boot. The point of this is to provide a shorter lease
time (so we don't exceed the size of the address pool when testing
boards) and also to allow different TFTP server addresses to be sent
to these boards.

I see that bp_vend[OPT_SIZE] exists in struct type Bootp_t. Is this a
vendor class id? I see around line 334 in bootp.c this is coppied from
BOOTP_VENDOR_MAGIC. Is setting a vendor class ID as simple as setting
a value for BOOTP_VENDOR_MAGIC in the config file? I cannot find an
example in any other board files.

Thanks,

Jeffrey Mann

[U-Boot-Users] DHCP vendor or class ID option

[Ben Warren]

Hi Jeff,

Jeffrey Mann wrote:
> U-boot users:
>
> I have been searching the list and reading source code trying to
> figure out if something that acomplishes vendor class ids or user
> class ids has been implemented in u-boot's dhcp services. (microsoft
> has a few articles that discuss uses of class IDS.
> http://support.microsoft.com/kb/266675)
>
> What I am trying to acomplish is this: I would like to be able to set
> slightly different DHCP options when the DHCP request comes from a
> board running u-boot. The point of this is to provide a shorter lease
> time (so we don't exceed the size of the address pool when testing
> boards) and also to allow different TFTP server addresses to be sent
> to these boards.
>
> I see that bp_vend[OPT_SIZE] exists in struct type Bootp_t. Is this a
> vendor class id? I see around line 334 in bootp.c this is coppied from
> BOOTP_VENDOR_MAGIC. Is setting a vendor class ID as simple as setting
> a value for BOOTP_VENDOR_MAGIC in the config file? I cannot find an
> example in any other board files.
>
> Thanks,
>
> Jeffrey Mann
>
>   
BOOTP_VENDOR_MAGIC is a fixed value (99.130.83.99) as defined in RFC 
1048, (and its successor, RFC 1533). You can implement whatever vendor 
extensions you want in U-boot. If you want to use vendor extensions, put 
this in your board's config header file:

#define CONFIG_BOOTP_VENDOREX

and supply the following two board functions:

u8 *dhcp_vendorex_prep (u8 *e); /* Function for filling in extensions */
u8 *dhcp_vendorex_proc (u8 *e); /* Function for processing the response */

There are a few boards in the tree that use this. Just grep for 
CONFIG_BOOTP_VENDOREX

You might want to read this, too, for syntax etc.:

http://www.faqs.org/rfcs/rfc1533.html

Does this make sense?

regards,
Ben