selftests: drv-net: probe for AF_XDP sockets more explicitly

Separate the support check from socket binding for easier refactoring.
Use: ./helper - - just to probe if we can open the socket.

Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Tested-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20250219234956.520599-5-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/drivers/net/queues.py b/tools/testing/selftests/drivers/net/queues.py
index b6896a57a5fd26fd7033dc74880f05b3b47488f2..0c959b2eb6180ffefa24b415eb58facd447e2675 100755 (executable)
--- a/tools/testing/selftests/drivers/net/queues.py
+++ b/tools/testing/selftests/drivers/net/queues.py
@@ -25,6 +25,13 @@ def nl_get_queues(cfg, nl, qtype='rx'):
     return None
 
 def check_xdp(cfg, nl, xdp_queue_id=0) -> None:
+    # Probe for support
+    xdp = cmd(cfg.rpath("xdp_helper") + ' - -', fail=False)
+    if xdp.ret == 255:
+        raise KsftSkipEx('AF_XDP unsupported')
+    elif xdp.ret > 0:
+        raise KsftFailEx('unable to create AF_XDP socket')
+
     xdp = subprocess.Popen([cfg.rpath("xdp_helper"), f"{cfg.ifindex}", f"{xdp_queue_id}"],
                            stdin=subprocess.PIPE, stdout=subprocess.PIPE, bufsize=1,
                            text=True)
@@ -33,11 +40,6 @@ def check_xdp(cfg, nl, xdp_queue_id=0) -> None:
     stdout, stderr = xdp.communicate(timeout=10)
     rx = tx = False
 
-    if xdp.returncode == 255:
-        raise KsftSkipEx('AF_XDP unsupported')
-    elif xdp.returncode > 0:
-        raise KsftFailEx('unable to create AF_XDP socket')
-
     queues = nl.queue_get({'ifindex': cfg.ifindex}, dump=True)
     if not queues:
         raise KsftSkipEx("Netlink reports no queues")

diff --git a/tools/testing/selftests/drivers/net/xdp_helper.c b/tools/testing/selftests/drivers/net/xdp_helper.c
index 80f86c2fe1a56a9ef3076deac01649fef482294a..2bad3b4d616c62c9ef93deead280eab20ffb743b 100644 (file)
--- a/tools/testing/selftests/drivers/net/xdp_helper.c
+++ b/tools/testing/selftests/drivers/net/xdp_helper.c
@@ -50,6 +50,13 @@ int main(int argc, char **argv)
                return 1;
        }
 
+       /* "Probing mode", just checking if AF_XDP sockets are supported */
+       if (!strcmp(argv[1], "-") && !strcmp(argv[2], "-")) {
+               printf("AF_XDP support detected\n");
+               close(sock_fd);
+               return 0;
+       }
+
        ifindex = atoi(argv[1]);
        queue = atoi(argv[2]);