IP fragmentation disagreement between current and stable

[Mike Silbersack]

On Tue, 22 Apr 2003, Don Lewis wrote:

> will contain 222 bytes of data.  With a 14 byte Ethernet header and a 20
> byte IP header, that just fits into one 256 byte mbuf.  I wonder if
> there is a divide by 4 to calculate the number of words, and the
>
> Could this be a driver problem instead of a problem in the stack itself?
> Both ends are fxp cards.

A similar problem was found with Via Rhine chips, where having multiple
packets exactly fill up the internal FIFO seemed to cause those packets to
be dropped.  Naturally, this only cropped up with fragmented ping packets
of certain lengths.  We never bothered patching it because, well, no clear
solution presented itself, and it wouldn't occur in normal usage.
(Actually, changing from store and forward back to smaller DMA sizes might
have fixed it, I'm not sure.)

So, I would not rule out the possibility of a driver / chipset bug.

Mike "Silby" Silbersack