[syslinux] atftpd versus tftpd-hpa

Gene Cumm gene.cumm at gmail.com
Fri Jul 9 12:02:07 PDT 2010


On Fri, Jul 9, 2010 at 14:22, H. Peter Anvin <hpa at zytor.com> wrote:
> On 07/09/2010 10:36 AM, Gene Cumm wrote:
>> It seems that tftpd-hpa is more suitable at serving arbitrarily large
>> files (greater than 65535 blocks long; with pxelinux.0 using a default
>> block size of 1408 this is 92,273,280 bytes) as atftpd will complain
>> in the log stating "Requested file to big, increase BLKSIZE".  I saw
>> that a while back HPA mentioned that atftpd was probably more scalable
>> (number of clients) while tftpd-hpa is more portable.  It looks like
>> tftpd-hpa supports block number rollover while atftpd doesn't seem to
>> (unless it's a runtime option that I can't find or a compile time
>> option).
>>
>> On the flip side, files this big are probably more suitably handled by
>> another means (gpxelinux.0 rather than pxelinux.0 with the large data
>> files on a standard web server).
>>
>
> Unfortunately atftpd development seems to have stopped entirely, and not
> supporting block rollover pretty much kills it.  Increasing blksize is
> not an option in a lot of cases, since most embedded TFTP stacks don't
> handle fragmented IP packets well.  PXELINUX uses 1408 bytes to fit in
> an Ethernet frame and still have 60 bytes to spare in case there is a
> tunneling solution somewhere in the system.  60 bytes is a bit small for
> that, of course.

I figured the reason for 1408 was along those lines but it's
interesting to note about the "extra" 60 bytes.

> There is a very low-level effort at getting TFTP support into Apache,
> but it seems to have gone on since 2003 with not much results.
>
> tftp-hpa is fairly constrained by the "must be psychotically portable"
> requirement.  That, fortunately, has made it widely adopted which is
> good since it solves a lot of serious problems.
>
> I also don't have much time to maintain it these days, which is a real
> problem.
>
>        -hpa

Aside from the scalabilty that you talked about (I think while atftpd
development might have been active), the only major improvements I
could see are the ability to increase its logging verbosity options
and the possibility of directing to a dedicated log file (which
syslog-ng can also address).

Are there any known issues or bugs in tftp-hpa's tftpd?

-- 
-Gene




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