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

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi lads,

> -----Original Message-----
> From: Liu, Jijiang
> Sent: Monday, December 01, 2014 1:08 PM
> To: Olivier MATZ; Ananyev, Konstantin
> Cc: dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH 1/3] mbuf:add two TX offload flags and change three fields
> 
> 
> 
> > -----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 tunnelling header as the UDP destination
> port indicate if a packet is VXLAN packet.

Actually it is my bad.
While looking at current implementation, I didn't realise that: ETHER_VXLAN_HLEN == (sizeof(struct udp_hdr) + sizeof(struct vxlan_hdr)).
So yes you are right for VXLAN packet it should be:
m->l2_len = sizeof(udp) + sizeof(vxlan) + sizeof(ether);
Sorry for confusing everyone.
Konstantin

> > Maybe adding outer_l4_len makes more sense.
> 
> >
> > Regards,
> > Olivier