Messages in this thread | | | From | Henrik Lindström <> | Subject | Re: macvtap performs IP defragmentation, causing MTU problems for virtual machines | Date | Thu, 05 Oct 2023 19:25:53 +0200 |
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On onsdag 4 oktober 2023 10:00:37 CEST Florian Westphal wrote: > Can you submit this formally, with proper changelog and Signed-off-by? > See scripts/checkpatch.pl in the kernel tree. Sure, i can give it a shot. How do i properly credit you if i submit your patch with some small changes of my own?
> You could also mention in changelog that this is ipv4 only because > ipv6 already considers the interface index during reassembly. Interesting. I've been trying to understand the code and it seems like ipv6 does defragmentation per-interface, while ipv4 does it "per-vrf" (correct me if i'm wrong). Is there any reason for this difference?
I also did some more testing with the diff from my previous mail. It looks like the problem remains for interfaces under vrfs. I think simply doing the bcast/mcast check first fixes that though, something like this: if (skb->pkt_type == PACKET_BROADCAST || skb->pkt_type == PACKET_MULTICAST) { if (dev) return dev->ifindex; }
return l3mdev_master_ifindex_rcu(dev); Does that look reasonable? The idea being that bcast/mcast packets are always defragmented per-interface, and unicast packets always "per-vrf".
Thanks, Henrik
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