On Tue, 2008-12-02 at 09:42 -0500, Andrew Gallatin wrote:Ben Hutchings wrote:[...]On Mon, 2008-12-01 at 19:02 -0500, Andrew Gallatin wrote:Ben Hutchings wrote:Indeed, and that is the patch I intend to submit if the fragmentSo you should check for IP fragmentation in your get_frag_header() alongIf your hardware/firmware wrongly claims to be able to verify theWe do partial checksums.
TCP/UDP checksum for an IP fragment, it seems to me you should deal with
that in your driver or fix the firmware.
with all the other checks you've got to do.
check in inet_lro is rejected. I still think the check belongs
in the inet lro code though, and I'm worried it is being rejected
for the wrong reasons..
There's a wide variety of capabilities of different hardware:
1. No checksum offload. Probably not worth using LRO.
2. Full-checksum generation. Driver passes packets to inet_lro;
get_frag_header() or get_skb_header() parses packets to check that they
are TCP/IPv4 and to validate the checksum. inet_lro does further checks.
3. L4 packet parsing and checksum validation. Driver passes TCP/IPv4
packets to inet_lro. inet_lro does further checks.
4. Hardware/firmware LRO. inet_lro not needed.
You seem to be proposing that a check that is only needed in case (2)
should also be applied in case (3). Maybe it would make more sense to
define a generic implementation of get_frag_header() for full-checksum
devices, if that's possible?