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From: "Liu, Jijiang" <jijiang.liu@intel.com>
To: Olivier MATZ <olivier.matz@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum offload
Date: Thu, 6 Nov 2014 11:24:11 +0000
Message-ID: <1ED644BD7E0A5F4091CF203DAFB8E4CC01D858A1@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <5459FBB2.1040408@6wind.com>



> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz@6wind.com]
> Sent: Wednesday, November 5, 2014 6:28 PM
> To: Liu, Jijiang
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v8 10/10] app/testpmd:test VxLAN Tx checksum
> offload
> 
> Hi Jijiang,
> 
> Thank you for your answer. Please find some comments below.
> 
> On 11/05/2014 07:02 AM, Liu, Jijiang wrote:
> >> First, the code checks if the mbuf has the flag PKT_RX_TUNNEL_IPV4_HDR.
> >> What is the meaning of this flag? It was added by [3], but there is
> >> no description in comments or in the commit log explaining in which
> >> case this flag is set by the driver. The name supposes that this flag
> >> is set when the received packet is an IPv4 tunnel, but the commit log talks
> about vxlan.
> >
> > The flag PKT_RX_TUNNEL_IPV4_HDR can be used for all tunneling packet types
> with outer IPV4 header.
> > For example:
> > IPv4 --> GRE/Teredo/VXLAN --> MAC --> IPv4:
> > MAC, IPV4, GRENAT, MAC, IPV4, SCTP, PAY4 MAC, IPV4, GRENAT, MAC, IPV6,
> > UDP, PAY4 MAC, IPV4, GRENAT, MAC, IPV6, UDP, PAY4 These tunneling
> > packet formats have a common point that is outer IPv4 header here.
> >
> > Only VXLAN tunneling packet is supported in DPDK for i40e now, so  the commit
> log talks about VXLAN .
> 
> Is it possible to have a more formal definition? For instance, is the following
> definition below correct?
> 
>   "the PKT_RX_TUNNEL_IPV4_HDR flag CAN be set by a driver if the packet
>    contains a tunneling protocol inside an IPv4 header".

Yes, correct.

> If the definition above is correct, I don't see how this flag can help an application
> to run faster. There is already a flag telling if there is a valid IPv4 header
> (PKT_RX_IPV4_HDR). As the PKT_RX_TUNNEL_IPV4_HDR flag does not tell what
> is ip->proto, the work done by an application to dissect a packet would be exactly
> the same with or without this flag.

If the PKT_RX_TUNNEL_IPV4_HDR flag is set, which means driver tell application that incoming packet is encapsulated packet, and application will process / analyse the packet according to tunneling format indicated by packet_type.

In terms of VXLAN packet format (MAC,IPv4,UDP,VXLAN,MAC,IP,TCP,PAY4), if only the PKT_RX_IPV4_HDR flag is set, and application regard its payload as "from VXLAN to PAY4", but actually, the real payload is PAY4.
  
> Please, can you give an example showing in which conditions this flag can help an
> application?

http://dpdk.org/ml/archives/dev/2014-October/007151.html
http://dpdk.org/ml/archives/dev/2014-October/007156.html

We used the PKT_RX_TUNNEL_IPV4_HDR in the two patches to help application identify incoming packet is tunneling packet.
 

  reply	other threads:[~2014-11-06 11:18 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-27  2:13 [dpdk-dev] [PATCH v8 00/10] Support VxLAN on Fortville Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 01/10] librte_mbuf:the rte_mbuf structure changes Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 02/10] librte_ether:add the basic data structures of VxLAN Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 03/10] librte_ether:add VxLAN packet identification API Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 04/10] i40e:support VxLAN packet identification in i40e Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 05/10] app/test-pmd:test VxLAN packet identification Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 06/10] librte_ether:add data structures of VxLAN filter Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 07/10] i40e:implement the API of VxLAN filter in librte_pmd_i40e Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 08/10] app/testpmd:test VxLAN packet filter Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 09/10] i40e:support VxLAN Tx checksum offload Jijiang Liu
2014-10-27  2:13 ` [dpdk-dev] [PATCH v8 10/10] app/testpmd:test " Jijiang Liu
2014-11-04  8:19   ` Olivier MATZ
2014-11-05  6:02     ` Liu, Jijiang
2014-11-05 10:28       ` Olivier MATZ
2014-11-06 11:24         ` Liu, Jijiang [this message]
2014-11-06 13:08           ` Olivier MATZ
2014-11-06 14:27             ` Liu, Jijiang
2014-11-07  0:43         ` Yong Wang
2014-11-07 17:16           ` Olivier MATZ
2014-11-10 11:39             ` Ananyev, Konstantin
2014-11-10 15:57               ` Olivier MATZ
2014-11-12  9:55                 ` Ananyev, Konstantin
2014-11-12 13:05                   ` Olivier MATZ
2014-11-12 13:40                     ` Thomas Monjalon
2014-11-12 23:14                       ` Ananyev, Konstantin
2014-11-12 14:39                     ` Ananyev, Konstantin
2014-11-12 14:56                       ` Olivier MATZ
     [not found]             ` <D0868B54.24DBB%yongwang@vmware.com>
2014-11-11  0:07               ` [dpdk-dev] FW: " Yong Wang
2014-11-10  6:03         ` [dpdk-dev] " Liu, Jijiang
2014-11-10 16:17           ` Olivier MATZ
     [not found]             ` <1ED644BD7E0A5F4091CF203DAFB8E4CC01D8F7A7@SHSMSX101.ccr.corp.intel.com>
2014-11-12 17:26               ` Thomas Monjalon
2014-11-13  5:35                 ` Liu, Jijiang
2014-11-13  5:39                   ` Liu, Jijiang
2014-11-13  6:51                 ` Liu, Jijiang
2014-11-13  9:10                   ` Thomas Monjalon
2014-11-14  8:15                     ` Liu, Jijiang
2014-11-14  9:09                       ` Olivier MATZ
2014-11-17  6:52                         ` Liu, Jijiang
2014-11-17 11:21                           ` Olivier MATZ
2014-11-20  7:28                             ` Liu, Jijiang
2014-11-20 16:36                               ` Olivier MATZ
2014-11-21  5:40                                 ` Liu, Jijiang
2014-10-27  2:20 ` [dpdk-dev] [PATCH v8 00/10] Support VxLAN on Fortville Liu, Yong
2014-10-27  2:41 ` Zhang, Helin
2014-10-27 13:46   ` Thomas Monjalon
2014-10-27 14:34     ` Liu, Jijiang
2014-10-27 15:15       ` Thomas Monjalon

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