[RFC PATCH 0/7] Support for virtio-net hash reporting

[Yuri Benditovich <yuri.benditovich@daynix.com>]

Existing TUN module is able to use provided "steering eBPF" to
calculate per-packet hash and derive the destination queue to
place the packet to. The eBPF uses mapped configuration data
containing a key for hash calculation and indirection table
with array of queues' indices.

This series of patches adds support for virtio-net hash reporting
feature as defined in virtio specification. It extends the TUN module
and the "steering eBPF" as follows:

Extended steering eBPF calculates the hash value and hash type, keeps
hash value in the skb->hash and returns index of destination virtqueue
and the type of the hash. TUN module keeps returned hash type in
(currently unused) field of the skb. 
skb->__unused renamed to 'hash_report_type'.

When TUN module is called later to allocate and fill the virtio-net
header and push it to destination virtqueue it populates the hash
and the hash type into virtio-net header.

VHOST driver is made aware of respective virtio-net feature that
extends the virtio-net header to report the hash value and hash report
type.

Yuri Benditovich (7):
  skbuff: define field for hash report type
  vhost: support for hash report virtio-net feature
  tun: allow use of BPF_PROG_TYPE_SCHED_CLS program type
  tun: free bpf_program by bpf_prog_put instead of bpf_prog_destroy
  tun: add ioctl code TUNSETHASHPOPULATION
  tun: populate hash in virtio-net header when needed
  tun: report new tun feature IFF_HASH

 drivers/net/tun.c           | 43 +++++++++++++++++++++++++++++++------
 drivers/vhost/net.c         | 37 ++++++++++++++++++++++++-------
 include/linux/skbuff.h      |  7 +++++-
 include/uapi/linux/if_tun.h |  2 ++
 4 files changed, 74 insertions(+), 15 deletions(-)

-- 
2.17.1