From: Paul Blakey
> Sent: 20 February 2022 13:21
>
> Ipv6 ttl, label and tos fields are modified without first
> pulling/pushing the ipv6 header, which would have updated
> the hw csum (if available). This might cause csum validation
> when sending the packet to the stack, as can be seen in
> the trace below.
>
> Fix this by updating skb->csum if available.
...
> +static inline __wsum
> +csum_block_replace(__wsum csum, __wsum old, __wsum new, int offset)
> +{
> + return csum_block_add(csum_block_sub(csum, old, offset), new, offset);
> +}
That look computationally OTT for sub 32bit adjustments.
It ought to be enough to do:
return csum_add(old_csum, 0xf0000fff + new - old);
Although it will need 'tweaking' for odd aligned 24bit values.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT,
UK
Registration No: 1397386 (Wales)
_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev
