Merge branch 'xdp: introduce xdp-feature support'

Merge branch 'xdp: introduce xdp-feature support'

Lorenzo Bianconi says:

====================

Introduce the capability to export the XDP features supported by the NIC.
Introduce a XDP compliance test tool (xdp_features) to check the features
exported by the NIC match the real features supported by the driver.
Allow XDP_REDIRECT of non-linear XDP frames into a devmap.
Export XDP features for each XDP capable driver.
Extend libbpf netlink implementation in order to support netlink_generic
protocol.
Introduce a simple generic netlink family for netdev data.

Changes since v4:
- rebase on top of bpf-next
- get rid of XDP_FEATURE_* enum in XDP compliance test tool
- rely on AF_INET6 address family and on IPv6-mapped-IPv6 addresses for IPv4
  in XDP compliance test tool
- add tsnep driver support

Changes since v3:
- add IPv6 support to XDP compliance test tool
- rely on network_helpers in XDP compliance test tool
- cosmetics changes

Changes since v2:
- rebase on top of bpf-next
- fix compilation error

Changes since v1:
- add Documentation to netdev.yaml
- use flags instead of enum as type for netdev.yaml definitions
- squash XDP_PASS, XDP_DROP, XDP_TX and XDP_ABORTED into XDP_BASIC since they
  are supported by all drivers.
- add notifier event to xdp_features_set_redirect_target() and
  xdp_features_clear_redirect_target()
- add selftest for xdp-features support in bpf_xdp_detach()
- add IPv6 preliminary support to XDP compliance test tool

Changes since RFCv2:
- do not assume fixed layout for genl kernel messages
- fix warnings in netdev_nl_dev_fill
- fix capabilities for nfp driver
- add supported_sg parameter to xdp_features_set_redirect_target and drop
  __xdp_features_set_redirect_target routine

Changes since RFCv1:
- Introduce netdev-genl implementation and get rid of rtnl one.
- Introduce netlink_generic support in libbpf netlink implementation
- Rename XDP_FEATURE_* in NETDEV_XDP_ACT_*
- Rename XDP_FEATURE_REDIRECT_TARGET in NETDEV_XDP_ACT_NDO_XMIT
- Rename XDP_FEATURE_FRAG_RX in NETDEV_XDP_ACT_RX_SG
- Rename XDP_FEATURE_FRAG_TARFET in NETDEV_XDP_ACT_NDO_XMIT
- Get rid of XDP_LOCK feature.
- Move xdp_feature field in a netdevice struct hole in the 4th cacheline.

Jakub Kicinski (1):
  netdev-genl: create a simple family for netdev stuff

Lorenzo Bianconi (5):
  libbpf: add the capability to specify netlink proto in
    libbpf_netlink_send_recv
  libbpf: add API to get XDP/XSK supported features
  bpf: devmap: check XDP features in __xdp_enqueue routine
  selftests/bpf: add test for bpf_xdp_query xdp-features support
  selftests/bpf: introduce XDP compliance test tool
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>