Messages in this thread | | | Date | Mon, 01 Dec 2008 19:02:19 -0500 | From | Andrew Gallatin <> | Subject | Re: [PATCH] lro: IP fragment checking |
| |
Ben Hutchings wrote: > On Mon, 2008-12-01 at 16:53 -0500, Andrew Gallatin wrote: >> David Miller wrote: >>> From: Andrew Gallatin <gallatin@myri.com> >>> Date: Mon, 01 Dec 2008 12:50:15 -0500 >>> >>>> As to whether or not to do it in the drivers/hardware or in the >>>> LRO code, I favor doing it in the LRO code just so that it is not >>>> missed in some driver. >>> Then there is no point in the hardware doing the check, if >>> we're going to check it anyways. >>> >>> That's part of my point about why this check doesn't belong >>> here. >> What hardware does an explicit check for fragmentation? > > Any that implements TCP/UDP checksumming properly.
How many do?
>> In most cases, aren't we just relying on the hardware checksum >> to be wrong on fragmented packets? That works 99.999% of the time, >> but the TCP checksum is pretty weak, and it is possible to >> have a fragmented packet where the first fragment has the same >> checksum as the entire packet. > [...] > > If your hardware/firmware wrongly claims to be able to verify the > TCP/UDP checksum for an IP fragment, it seems to me you should deal with > that in your driver or fix the firmware.
We do partial checksums.
Drew
| |