Re: [PATCH net] bonding: fix ICMPv6 header handling when receiving IPv6 messages

[Hangbin Liu <liuhangbin@gmail.com>]

On Tue, Nov 01, 2022 at 11:12:43AM +0100, Jay Vosburgh wrote:
> Hangbin Liu <liuhangbin@gmail.com> wrote:
> 
> >Some drivers, like bnx2x, will call ipv6_gro_receive() and set skb
> >IPv6 transport header before bond_handle_frame(). But some other drivers,
> >like be2net, will not call ipv6_gro_receive() and skb transport header
> >is not set properly. Thus we can't use icmp6_hdr(skb) to get the icmp6
> >header directly when dealing with IPv6 messages.
> 
> 	I don't understand this explanation, as ipv6_gro_receive() isn't
> called directly by the device drivers, but from within the GRO
> processing, e.g., by dev_gro_receive().
> 
> 	Could you explain how the call paths actually differ?  

Er..Yes, it's a little weird.

I checked if the transport header is set before  __netif_receive_skb_core().
The bnx2x driver set it while be2net does not. So the transport header is reset
in __netif_receive_skb_core() with be2net.

I also found ipv6_gro_receive() is called before bond_handle_frame() when
receive NA message. Not sure which path it go through. I'm not very familiar
with driver part. But I can do more investigating.

Thanks
Hangbin