[PATCH iproute2-next v2 0/4] Support for nexthop group statistics

[Petr Machata <petrm@nvidia.com>]

Next hop group stats allow verification of balancedness of a next hop
group. The feature was merged in kernel commit 7cf497e5a122 ("Merge branch
'nexthop-group-stats'"). This patchset adds to ip the corresponding
support.

NH group stats come in two flavors: as statistics for SW and for HW
datapaths. The former is shown when -s is given to "ip nexthop". The latter
demands more work from the kernel, and possibly driver and HW, and might
not be always necessary. Therefore tie it to -s -s, similarly to how ip
link shows more detailed stats when -s is given twice.

Here's an example usage:

 # ip link add name gre1 up type gre \
      local 172.16.1.1 remote 172.16.1.2 tos inherit
 # ip nexthop replace id 1001 dev gre1
 # ip nexthop replace id 1002 dev gre1
 # ip nexthop replace id 1111 group 1001/1002 hw_stats on
 # ip -s -s -j -p nexthop show id 1111
 [ {
 	[ ...snip... ]
         "hw_stats": {
             "enabled": true,
             "used": true
         },
         "group_stats": [ {
                 "id": 1001,
                 "packets": 0,
                 "packets_hw": 0
             },{
                 "id": 1002,
                 "packets": 0,
                 "packets_hw": 0
             } ]
     } ]

hw_stats.enabled shows whether hw_stats have been requested for the given
group. hw_stats.used shows whether any driver actually implemented the
counter. group_stats[].packets show the total stats, packets_hw only the
HW-datapath stats.

v2:
- Patch #1:
    - have rta_getattr_uint() support 8- and 16-bit quantities as well
- Patch #2:
    - Use print_nl() for the newlines

Petr Machata (4):
  libnetlink: Add rta_getattr_uint()
  ip: ipnexthop: Support dumping next hop group stats
  ip: ipnexthop: Support dumping next hop group HW stats
  ip: ipnexthop: Allow toggling collection of nexthop group HW
    statistics

 include/libnetlink.h  |  14 +++++
 ip/ipnexthop.c        | 129 ++++++++++++++++++++++++++++++++++++++++++
 ip/nh_common.h        |  11 ++++
 man/man8/ip-nexthop.8 |   2 +
 4 files changed, 156 insertions(+)

-- 
2.43.0