From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jerry Van Baren <gerald.vanbaren@ge.com>
Date: Wed, 11 Jun 2008 13:33:41 -0400
Subject: [U-Boot-Users] Does u-boot handle packet fragmentation during
 TFTP?
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John Linn wrote:
> I searched the archives and the docs and didn?t see anything specific to 
> fragmentation.  I?m developing an LL TEMAC driver for u-boot on Xilinx 
> boards and am seeing an issue.
> 
> If the TFTP server providing the kernel image is not fragmenting 
> packets, I can transfer a kernel image fine.  But if the TFTP server 
> fragments packets I see problems.  I?m sure it?s a problem with my new 
> driver, but wanted to make sure there?s not any known issues with u-boot 
> in this area.
> 
> Thanks,
> John

The code says "no."

<http://git.denx.de/?p=u-boot.git;a=blob;f=net/net.c;h=78128772fe5cda166ea74aa8ac95832d8d155b55;hb=HEAD#l1407>

if (ip->ip_off & htons(0x1fff)) { /* Can't deal w/ fragments */
         return;

That's too bad, bigger packets can help substantially with throughput on 
TFTP (throughput is hammered by latency with TFTP).  Something to think 
about... doing simple reassembly (only handle in-sequence reassembly) is 
fairly simple.

Best regards,
gvb