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

["Liu, Jijiang" <jijiang.liu@intel.com>]

> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz@6wind.com]
> Sent: Monday, December 1, 2014 8:28 PM
> To: Ananyev, Konstantin; Liu, Jijiang
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH 1/3] mbuf:add two TX offload flags and change
> three fields
> 
> 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?
I agree to include the size of UDP in l2_len, for VXLAN, the UDP header is a part of VXLAN tunneling header as the UDP destination port indicate if a packet is VXLAN packet.
> Maybe adding outer_l4_len makes more sense.

> 
> Regards,
> Olivier