[v4,0/4] tools: bpftool: add net attach/detach command to attach XDP prog

["Daniel T. Lee" <danieltimlee@gmail.com>]

Currently, bpftool net only supports dumping progs attached on the
interface. To attach XDP prog on interface, user must use other tool
(eg. iproute2). By this patch, with `bpftool net attach/detach`, user
can attach/detach XDP prog on interface.

    # bpftool prog
        16: xdp  name xdp_prog1  tag 539ec6ce11b52f98  gpl
        loaded_at 2019-08-07T08:30:17+0900  uid 0
        ...
        20: xdp  name xdp_fwd_prog  tag b9cb69f121e4a274  gpl
        loaded_at 2019-08-07T08:30:17+0900  uid 0

    # bpftool net attach xdpdrv id 16 dev enp6s0np0
    # bpftool net
    xdp:
        enp6s0np0(4) driver id 16

    # bpftool net attach xdpdrv id 20 dev enp6s0np0 overwrite
    # bpftool net
    xdp:
        enp6s0np0(4) driver id 20

    # bpftool net detach xdpdrv dev enp6s0np0
    # bpftool net
    xdp:


While this patch only contains support for XDP, through `net
attach/detach`, bpftool can further support other prog attach types.

XDP attach/detach tested on Mellanox ConnectX-4 and Netronome Agilio.

---
Changes in v4:
  - rename variable, attach/detach error message enhancement
  - bash-completion cleanup, doc update with brief description (attach types)

Changes in v3:
  - added 'overwrite' option for replacing previously attached XDP prog
  - command argument order has been changed ('ATTACH_TYPE' comes first)
  - add 'dev' keyword in front of <devname>
  - added bash-completion and documentation

Changes in v2:
  - command 'load/unload' changed to 'attach/detach' for the consistency

Daniel T. Lee (4):
  tools: bpftool: add net attach command to attach XDP on interface
  tools: bpftool: add net detach command to detach XDP on interface
  tools: bpftool: add bash-completion for net attach/detach
  tools: bpftool: add documentation for net attach/detach

 .../bpf/bpftool/Documentation/bpftool-net.rst |  57 +++++-
 tools/bpf/bpftool/bash-completion/bpftool     |  65 ++++++-
 tools/bpf/bpftool/net.c                       | 176 +++++++++++++++++-
 3 files changed, 278 insertions(+), 20 deletions(-)

-- 
2.20.1