[dpdk-dev] [PATCH v2 1/5] ethdev: introduce Tx generic tunnel offloads

[Xueming(Steven) Li]

Hi Konstantin,

> -----Original Message-----
> From: Ananyev, Konstantin [mailto:konstantin.ananyev at intel.com]
> Sent: Tuesday, January 30, 2018 12:49 AM
> To: Xueming(Steven) Li <xuemingl at mellanox.com>; Olivier MATZ
> <olivier.matz at 6wind.com>
> Cc: dev at dpdk.org; Wu, Jingjing <jingjing.wu at intel.com>; Shahaf Shuler
> <shahafs at mellanox.com>; Yongseok Koh <yskoh at mellanox.com>; Thomas Monjalon
> <thomas at monjalon.net>; Yigit, Ferruh <ferruh.yigit at intel.com>
> Subject: RE: [dpdk-dev] [PATCH v2 1/5] ethdev: introduce Tx generic tunnel
> offloads
> 
> Hi Xueming,
> 
> >
> > This patch introduce new TX offloads flag for devices that support
> > tunnel agnostic checksum and TSO offloads.
> >
> > The support from the device is for inner and outer checksums on
> > IPV4/TCP/UDP and TSO for *any packet with the following format*:
> >
> > < some headers > / [optional IPv4/IPv6] / [optional TCP/UDP] / <some
> > headers> / [optional inner IPv4/IPv6] / [optional TCP/UDP]
> >
> > For example the following packets can use this feature:
> >
> > 1. eth / ipv4 / udp / VXLAN / ip / tcp 2. eth / ipv4 / GRE / MPLS /
> > ipv4 / udp
> 
> So in terms of usage - what is the difference with current TSO types?
> Konstantin
> 

Traditionally, HW only recognize "known" tunnel type, do TSO calculation
based on L3/L4 headers known to tunnel type. For example, it must be 
L2 header after VXLAN, then L3. While this Generic offloading provides
inner/outer L3/L4 header info(len and offset) to HW, and thus tunnel 
info become less important. Please note the MPLS over GRE tunnel in last
example above.

> >
> > Signed-off-by: Xueming Li <xuemingl at mellanox.com>
> > ---
> >  lib/librte_ether/rte_ethdev.h | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/lib/librte_ether/rte_ethdev.h
> > b/lib/librte_ether/rte_ethdev.h index 1a5b4cdc5..d8d08ccb2 100644
> > --- a/lib/librte_ether/rte_ethdev.h
> > +++ b/lib/librte_ether/rte_ethdev.h
> > @@ -979,6 +979,16 @@ struct rte_eth_conf {
> >   *   the same mempool and has refcnt = 1.
> >   */
> >  #define DEV_TX_OFFLOAD_SECURITY         0x00020000
> > +/**< Device supports generic tunnel checksum and TSO offloading.
> > + * Checksum and TSO are done based on following mbuf fields:
> > + *   - Length of each header
> > + *   - Type of outer/inner L3 type, IPv4 or IPv6
> > + *   - Type of outer/inner L4 type, TCP or UDP.
> > + *	- PKT_TX_TUNNEL_VXLAN implies outer UDP type.
> > + *	- PKT_TX_TCP_SEG implies inner TCP type.
> > + * Tunnel type is optional except PKT_TX_TUNNEL_VXLAN to hint outer UDP.
> > + */
> > +#define DEV_TX_OFFLOAD_GENERIC_TNL_CKSUM_TSO	0x00040000
> >
> >  /*
> >   * If new Tx offload capabilities are defined, they also must be
> > --
> > 2.13.3