Updated netlink dependency version

[almaslennikov]

The version of netlink introduced in #395 breaks the use case of getting eswitch mode of pci device, introduced in the same PR.

Here's a comparison table of results from several version of netlink compared against each other and devlink cmd:

PCI device	devlink report	netlink v1.1.1-0.20210518155637-4cb3795f2ccb (broken)	netlink v1.1.0 (previous)	netlink master vishvananda/netlink@b10eb8f
PF in switchdev eswitch mode	mode switchdev inline-mode none encap enable	mode="", err=nil	switchdev	switchdev
PF in legacy eswitch mode	mode legacy inline-mode none encap disable	mode="", err=nil	legacy	legacy
VF for switchdev PF	devlink answers: Operation not supported	mode="", err=nil	mode="", err=nil	mode="", err=nil
VF for legacy PF	devlink answers: Operation not supported	mode="", err=nil	mode="", err=nil	mode="", err=nil
non-sriov PF	devlink answers: Operation not supported	mode="", err=nil	mode="", err=nil	mode="", err=nil

The broken version of netlink reports empty eswitch mode for sriov enabled devices.

So, to fix the issue, upgrading the version of netlink to the current master. We can't downgrade to the previously used version because https://github.com/Mellanox/sriovnet/ dependency relies on a newer version.

Also, changed the error handling because devlink's "Operation not supported" results in empty value from netlink.
Here's the logs from my machine:

• Intel Corporation I350 Gigabit Network Connection
  [utils.go:66] Getting pf name for 0000:01:00.1
  [utils.go:73] Devlink query for eswitch mode is not supported for device 0000:01:00.1. error getting devlink device attributes for net device 0000:01:00.1 no such device
  [utils.go:89] Using default flow

• ConnectX 6 switchdev VFs
  [utils.go:66] Getting pf name for 0000:03:00.2
  [utils.go:78] Using switchdev flow
  [utils.go:66] Getting pf name for 0000:03:00.3
  [utils.go:78] Using switchdev flow
  [utils.go:66] Getting pf name for 0000:03:00.4
  [utils.go:78] Using switchdev flow
  [utils.go:66] Getting pf name for 0000:03:00.5
  [utils.go:78] Using switchdev flow

• ConnectX 6 legacy vfs
  [utils.go:66] Getting pf name for 0000:03:00.7
  [utils.go:89] Using default flow
  [utils.go:66] Getting pf name for 0000:03:01.0
  [utils.go:89] Using default flow
  [utils.go:66] Getting pf name for 0000:03:01.1
  [utils.go:89] Using default flow
  [utils.go:66] Getting pf name for 0000:81:00.0
  [utils.go:73] Devlink query for eswitch mode is not supported for device 0000:81:00.0.
  [utils.go:89] Using default flow

[zshi-redhat]

Thanks for the detailed comparision tests!

Also, changed the error handling because devlink's "Operation not supported" results in empty value from netlink. Here's the logs from my machine:

So we won't see the "Operation not supported" message by calling GetPfEswitchMode, It just returns empty value and nil error, right? that's why the handling of "Operation not supported" is removed if I understand correctly.

[almaslennikov]

@zshi-redhat Yes, that's right