Re: [dpdk-dev] PKT_RX_VLAN_PKT when VLAN stripping is disabled

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

Hi Olivier,

> -----Original Message-----
> From: Olivier Matz [mailto:olivier.matz@6wind.com]
> Sent: Monday, April 25, 2016 2:51 PM
> To: Ananyev, Konstantin; 'John Daley (johndale)'; dev@dpdk.org
> Subject: Re: [dpdk-dev] PKT_RX_VLAN_PKT when VLAN stripping is disabled
> 
> Hi,
> 
> On 04/25/2016 02:02 PM, Ananyev, Konstantin wrote:
> > Hi John,
> > From rte_mbuf.h:
> > #define PKT_RX_VLAN_PKT      (1ULL << 0)  /**< RX packet is a 802.1q VLAN packet. */
> > So yes, in theory it should be set up for vlan packet with both stripping on/off.
> > The problem is that (as far as I know) when VLAN stripping is disabled  FVL RXD doesn't contain information
> > does that packet contain a VLAN or not.
> > Don't really know what is the best option in that case: keep things as it is or change the meaning of
> > the VLAN_PKT flag to indicate is mbuf.vlan_tci field is valid or not.
> > Konstantin
> 
> It seems the meaning of the PKT_RX_VLAN_PKT bit depends on the port
> configuration:
> - if vlan stripping is configured, it means VLAN is present in vlan_tci
>   mbuf field
> - if not configured, it means a VLAN is present in the packet
> 
> I don't think this is a good behavior since the application has to know
> the port configuration to properly interpret the meaning of the flag.
> 
> I suggest to change the meaning of this flag to: "vlan was stripped by
> hardware, and vlan tag is now located in m->vlan_tci".
> 
> The same could apply to PKT_RX_QINQ_PKT and m->outer_vlan_tci.
> 
> We could add a new packet_type to tell if the mbuf is a VLAN/QinQ is
> detected in the packet but not stripped.
> 
> Example:
> 
> - vlan stripping is disabled
> 
>   - vlan packet recvd: flags=0, ptype=RTE_PTYPE_L2_ETHER_VLAN
>   - qinq packet recvd: flags=0, ptype=RTE_PTYPE_L2_ETHER_QINQ
> 
> - vlan stripping is enabled
> 
>   - vlan packet recvd: flags=PKT_RX_VLAN_PKT, ptype=RTE_PTYPE_L2_ETHER,
>         m->vlan_tci=id
>   - qinq packet recvd: flags=PKT_RX_VLAN_PKT|PKT_RX_QINQ_PKT,
>         ptype=RTE_PTYPE_L2_ETHER, m->vlan_tci=id, m->vlan_tci_outer=id
> 
> 
> Thoughts?

Sounds like a reasonable change to me.
Konstantin


> 
> 
> 
> >
> >> -----Original Message-----
> >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of John Daley (johndale)
> >> Sent: Friday, April 22, 2016 12:37 AM
> >> To: dev@dpdk.org
> >> Subject: [dpdk-dev] PKT_RX_VLAN_PKT when VLAN stripping is disabled
> >>
> >> Hi,
> >>
> >> When VLAN stripping is disabled, X710 and 82599ES act differently for me in this case when receiving VLAN tagged packets. On
> >> 82599ES the flag is set but on X710 the flag not set.
> >>
> >> Do I maybe have old X710 firmware? Or is it not set for X710 on purpose in this case and instead the flag is used to indicate if
> vlan_tci is
> >> valid? Right now the enic pmd does what my X710 does, which I think is incorrect and I want to fix it.
> >>
> >> Thanks,
> >> John
> >