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

[Ananyev, Konstantin]

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.

Ok, but I wonder when the user would like to do TSO on tunnel packet, for this offload -
would he need to do something differently from what he has to do now:
raise PKT_TX_TCP_SEG and related flags, raise appropriate PKT_TX_TUNNEL_* flag,
fill l2_len, l3_len, l4_len,tso_segsz,outer_l2_len,outer_l3_len? 

Konstantin

> 
> > >
> > > 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