[RFC net-next 1/4] selftests: drv-net: tso: retry connect on EHOSTUNREACH

[Xu Du]

The TSO test occasionally fails with "No route to host" (EHOSTUNREACH)
when connecting to the remote socat listener. This can happen when the
neighbor resolution has not yet completed by the time the test attempts
to connect, particularly in tunnel setups where neighbor entries may
take slightly longer to establish.

Add a retry loop (up to 5 attempts with 0.5s delay) around the
sock.connect() call to handle this transient condition gracefully.

Signed-off-by: Xu Du <xudu@xxxxxxxxxx>
---
 tools/testing/selftests/drivers/net/hw/tso.py | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/tso.py b/tools/testing/selftests/drivers/net/hw/tso.py
index bb675e3dac88..f792115adfb3 100755
--- a/tools/testing/selftests/drivers/net/hw/tso.py
+++ b/tools/testing/selftests/drivers/net/hw/tso.py
@@ -3,6 +3,7 @@
 
 """Run the tools/testing/selftests/net/csum testsuite."""
 
+import errno
 import fcntl
 import socket
 import struct
@@ -47,10 +48,20 @@ def run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso):
 
         if ipver == "4":
             sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-            sock.connect((remote_v4, port))
+            sockaddr = (remote_v4, port)
         else:
             sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
-            sock.connect((remote_v6, port))
+            sockaddr = (remote_v6, port)
+
+        for attempt in range(5):
+            try:
+                sock.connect(sockaddr)
+                break
+            except OSError as e:
+                if e.errno == errno.EHOSTUNREACH and attempt < 4:
+                    time.sleep(0.5)
+                else:
+                    raise
 
         # Small send to make sure the connection is working.
         sock.send("ping".encode())
-- 
2.53.0