[PATCH v4 0/2] Enhance network interface feature testing

[Abhinav Jain <jain.abhinav177@gmail.com>]

This small series includes fixes for creation of veth pairs for
networkless kernels & adds tests for turning the different network
interface features on and off in selftests/net/netdevice.sh script.

Changes in v4:
Move veth creation/removal to the main shell script.
Tested using vng on a networkless kernel and the script works, sample
output below the changes.

Changes in v3:
https://lore.kernel.org/all/20240614113240.41550-1-jain.abhinav177@gmail.com/

Add a check for netdev, create veth pair for testing.
Restore feature to its initial state.

Changes in v2:
https://lore.kernel.org/all/20240609132124.51683-1-jain.abhinav177@gmail.com/

Remove tail usage; use read to parse the features from temp file.

v1:
https://lore.kernel.org/all/20240606212714.27472-1-jain.abhinav177@gmail.com/

```
# selftests: net: netdevice.sh
# No valid network device found, creating veth pair
# PASS: veth0: set interface up
# PASS: veth0: set MAC address
# SKIP: veth0: set IP address
# PASS: veth0: ethtool list features
# PASS: veth0: Turned off feature: rx-checksumming
# PASS: veth0: Turned on feature: rx-checksumming
# PASS: veth0: Restore feature rx-checksumming to initial state on
# Actual changes:
# tx-checksum-ip-generic: off
# tx-tcp-segmentation: off [not requested]
....
....
....
# PASS: veth1: Restore feature tx-nocache-copy to initial state off
# PASS: veth1: Turned off feature: tx-vlan-stag-hw-insert
# PASS: veth1: Turned on feature: tx-vlan-stag-hw-insert
# PASS: veth1: Restore feature tx-vlan-stag-hw-insert to initial state on
# PASS: veth1: Turned off feature: rx-vlan-stag-hw-parse
# PASS: veth1: Turned on feature: rx-vlan-stag-hw-parse
# PASS: veth1: Restore feature rx-vlan-stag-hw-parse to initial state on
# PASS: veth1: Turned off feature: rx-gro-list
# PASS: veth1: Turned on feature: rx-gro-list
# PASS: veth1: Restore feature rx-gro-list to initial state off
# PASS: veth1: Turned off feature: rx-udp-gro-forwarding
# PASS: veth1: Turned on feature: rx-udp-gro-forwarding
# PASS: veth1: Restore feature rx-udp-gro-forwarding to initial state off
# Cannot get register dump: Operation not supported
# SKIP: veth1: ethtool dump not supported
# PASS: veth1: ethtool stats
# PASS: veth1: stop interface
# Removed veth pair
ok 12 selftests: net: netdevice.sh
```
Abhinav Jain (2):
  selftests: net: Create veth pair for testing in networkless kernel
  selftests: net: Add on/off checks for non-fixed features of interface

 tools/testing/selftests/net/netdevice.sh | 55 +++++++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

--
2.34.1