Messages in this thread | | | Date | Wed, 16 Mar 2022 08:45:05 -0600 | Subject | Re: [PATCH net-next 1/3] net: gre_demux: add skb drop reasons to gre_rcv() | From | David Ahern <> |
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On 3/15/22 10:53 PM, Menglong Dong wrote: > On Wed, Mar 16, 2022 at 11:49 AM David Ahern <dsahern@kernel.org> wrote: >> >> On 3/15/22 9:08 PM, Jakub Kicinski wrote: >>> On Mon, 14 Mar 2022 21:33:10 +0800 menglong8.dong@gmail.com wrote: >>>> + reason = SKB_DROP_REASON_NOT_SPECIFIED; >>>> if (!pskb_may_pull(skb, 12)) >>>> goto drop; >>> >>> REASON_HDR_TRUNC ? >>> >>>> ver = skb->data[1]&0x7f; >>>> - if (ver >= GREPROTO_MAX) >>>> + if (ver >= GREPROTO_MAX) { >>>> + reason = SKB_DROP_REASON_GRE_VERSION; >>> >>> TBH I'm still not sure what level of granularity we should be shooting >>> for with the reasons. I'd throw all unexpected header values into one >>> bucket, not go for a reason per field, per protocol. But as I'm said >>> I'm not sure myself, so we can keep what you have.. >> >> I have stated before I do not believe every single drop point in the >> kernel needs a unique reason code. This is overkill. The reason augments >> information we already have -- the IP from kfree_skb tracepoint. > > Is this reason unnecessary? I'm not sure if the GRE version problem should > be reported. With versions not supported by the kernel, it seems we > can't get the > drop reason from the packet data, as they are fine. And previous seems not > suitable here, as it is a L4 problem. >
Generically, it is "no support for a protocol version". That kind of reason code + the IP tells you GRE is processing a packet with an unsupported protocol version.
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