Re: [dpdk-dev] [PATCH 1/3] mbuf:add two TX offload flags and change three fields

[Olivier MATZ <olivier.matz@6wind.com>]

Hi Konstantin,

On 12/01/2014 12:58 PM, Ananyev, Konstantin wrote:
>> Ether/IP/UDP/vxlan/Ether/IP/UDP/xxx
>>   m->outer_l2_len = sizeof(ether)
>>   m->outer_l3_len = sizeof(ip)
>>   m->l2_len = sizeof(udp) + sizeof(vxlan) + sizeof(ether)
> 
> I think it should be:
> m->l2_len = sizeof(vxlan) + sizeof(ether)
> 
> We don't need to add sizeof(udp) as we already say to the HW that I t will be UDP TUNNELING vi the ol_flag: PKT_TX_UDP_TUNNEL_PKT.
> 
>>   m->l3_len = sizeof(ip)
>>   m->l4_len = sizeof(udp)

I would agree if we had a m->outer_l4_len. Maybe we should add
it to be coherent with lX_len fields?

I think that to process the inner IP checksum, we should be able
to use these 2 notations:

Ether/IP/GRE/IP/UDP/xxx
  m->flags = OUTER_IP_CKSUM
  m->outer_l2_len = sizeof(ether)
  m->outer_l3_len = sizeof(ip)
  m->l2_len = sizeof(gre)
  m->l3_len = sizeof(ip)
  m->l4_len = sizeof(udp)

Ether/IP/GRE/IP/UDP/xxx
  m->flags = IP_CKSUM
  /* sum of all outer_lX_len and l2_len from above: */
  m->l2_len = sizeof(ether) + sizeof(ip) + sizeof(gre)
  m->l3_len = sizeof(ip)
  m->l4_len = sizeof(udp)

So, in case of vxlan, I suggest that either we include the size of
UDP in l2_len, or we add a outer_l4_len. What do you think?

Maybe adding outer_l4_len makes more sense.

Regards,
Olivier