[gPXE] relative URIs with colons (or, how can you use ${mac} in a file name)

[Timothy Stack]

Hi,

Using gpxe 0.9.7, I'd like to chainload a file over TFTP that is named 
with the host's MAC address.  Unfortunately, just doing "chain ${mac}" 
doesn't work because gpxe sees the colon in the mac address and thinks 
it's an absolute URI instead of a relative one.  The file open then 
fails because this scheme is unsupported.  I figure that gpxe should 
consider an unsupported URI scheme as a relative URI, so I made a change 
to "parse_uri" to check that the scheme was supported.  This seems to 
work fine.

Are there any other alternatives?  pxelinux uses dashes as separators 
for the MAC address when it does it's query.  I'd rather not have to 
specify an absolute URI to get things working.

thanks,

tim