selftests: drv-net: add a trivial ping test

Add a very simple test for testing with a remote system.
Both IPv4 and IPv6 connectivity is optional, later change
will add checks to skip tests based on available addresses.

Using netdevsim:

 $ ./run_kselftest.sh -t drivers/net:ping.py
 TAP version 13
 1..1
 # timeout set to 45
 # selftests: drivers/net: ping.py
 # KTAP version 1
 # 1..2
 # ok 1 ping.test_v4
 # ok 2 ping.test_v6
 # # Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0
 ok 1 selftests: drivers/net: ping.py

Command line SSH:

 $ NETIF=virbr0 REMOTE_TYPE=ssh REMOTE_ARGS=root@192.168.122.123 \
    LOCAL_V4=192.168.122.1 REMOTE_V4=192.168.122.123 \
    ./tools/testing/selftests/drivers/net/ping.py
 KTAP version 1
 1..2
 ok 1 ping.test_v4
 ok 2 ping.test_v6 # SKIP Test requires IPv6 connectivity
 # Totals: pass:1 fail:0 xfail:1 xpass:0 skip:0 error:0

Existing devices placed in netns (and using net.config):

 $ cat drivers/net/net.config
 NETIF=veth0
 REMOTE_TYPE=netns
 REMOTE_ARGS=red
 LOCAL_V4="192.168.1.1"
 REMOTE_V4="192.168.1.2"

 $ ./run_kselftest.sh -t drivers/net:ping.py
 TAP version 13
 1..1
 # timeout set to 45
 # selftests: drivers/net: ping.py
 # KTAP version 1
 # 1..2
 # ok 1 ping.test_v4
 # ok 2 ping.test_v6 # SKIP Test requires IPv6 connectivity
 # # Totals: pass:1 fail:0 xfail:1 xpass:0 skip:0 error:0
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20240420025237.3309296-5-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/drivers/net/Makefile

@@ -2,6 +2,9 @@
 
 TEST_INCLUDES := $(wildcard lib/py/*.py)
 
-TEST_PROGS := stats.py
+TEST_PROGS := \
+	ping.py \
+	stats.py \
+# end of TEST_PROGS
 
 include ../../lib.mk

tools/testing/selftests/drivers/net/ping.py

+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+from lib.py import ksft_run, ksft_exit
+from lib.py import NetDrvEpEnv
+from lib.py import cmd
+
+
+def test_v4(cfg) -> None:
+    cmd(f"ping -c 1 -W0.5 {cfg.remote_v4}")
+    cmd(f"ping -c 1 -W0.5 {cfg.v4}", host=cfg.remote)
+
+
+def test_v6(cfg) -> None:
+    cmd(f"ping -c 1 -W0.5 {cfg.remote_v6}")
+    cmd(f"ping -c 1 -W0.5 {cfg.v6}", host=cfg.remote)
+
+
+def main() -> None:
+    with NetDrvEpEnv(__file__) as cfg:
+        ksft_run([test_v4, test_v6],
+                 args=(cfg, ))
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()