[PATCH net-next v5 3/3] selftests: drv-net: Test queue xsk attribute

Joe Damato
2025-02-08T04:14:42Z

Test that queues which are used for AF_XDP have the xsk nest attribute.
The attribute is currently empty, but its existence means the AF_XDP is
being used for the queue.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
---
v3:
- Change comment style of helper C program to avoid kdoc warnings as
suggested by Jakub. No other changes.

v2:
- Updated the Python test after changes to patch 1 which expose an
empty nest
- Updated Python test with general Python coding feedback

.../testing/selftests/drivers/net/.gitignore | 2 +
tools/testing/selftests/drivers/net/Makefile | 3 +
tools/testing/selftests/drivers/net/queues.py | 35 +++++++-
.../selftests/drivers/net/xdp_helper.c | 89 +++++++++++++++++++
4 files changed, 127 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/drivers/net/.gitignore
create mode 100644 tools/testing/selftests/drivers/net/xdp_helper.c

diff --git a/tools/testing/selftests/drivers/net/.gitignore b/tools/testing/selftests/drivers/net/.gitignore
new file mode 100644
index 000000000000..ec746f374e85
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/.gitignore
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+xdp_helper
diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile
index c7f1c443f2af..81961c6e059d 100644
--- a/tools/testing/selftests/drivers/net/Makefile
+++ b/tools/testing/selftests/drivers/net/Makefile
@@ -1,10 +1,13 @@
# SPDX-License-Identifier: GPL-2.0
+CFLAGS += $(KHDR_INCLUDES)

TEST_INCLUDES := $(wildcard lib/py/*.py) \
$(wildcard lib/sh/*.sh) \
../../net/net_helper.sh \
../../net/lib.sh \

+TEST_GEN_PROGS := xdp_helper
+
TEST_PROGS := \
netcons_basic.sh \
netcons_fragmented_msg.sh \
diff --git a/tools/testing/selftests/drivers/net/queues.py b/tools/testing/selftests/drivers/net/queues.py
index 38303da957ee..55c2b296ad3c 100755
--- a/tools/testing/selftests/drivers/net/queues.py
+++ b/tools/testing/selftests/drivers/net/queues.py
@@ -8,7 +8,10 @@ from lib.py import NetDrvEnv
from lib.py import cmd, defer, ip
import errno
import glob
-
+import os
+import socket
+import struct
+import subprocess

def sys_get_queues(ifname, qtype='rx') -> int:
folders = glob.glob(f'/sys/class/net/{ifname}/queues/{qtype}-*')
@@ -21,6 +24,34 @@ def nl_get_queues(cfg, nl, qtype='rx'):
return len([q for q in queues if q['type'] == qtype])
return None

+def check_xdp(cfg, nl, xdp_queue_id=0) -> None:
+ test_dir = os.path.dirname(os.path.realpath(__file__))
+ xdp = subprocess.Popen([f"{test_dir}/xdp_helper", f"{cfg.ifindex}", f"{xdp_queue_id}"],
+ stdin=subprocess.PIPE, stdout=subprocess.PIPE, bufsize=1,
+ text=True)
+ defer(xdp.kill)
+
+ stdout, stderr = xdp.communicate(timeout=10)
+ rx = tx = False
+
+ queues = nl.queue_get({'ifindex': cfg.ifindex}, dump=True)
+ if not queues:
+ raise KsftSkipEx("Netlink reports no queues")
+
+ for q in queues:
+ if q['id'] == 0:
+ if q['type'] == 'rx':
+ rx = True
+ if q['type'] == 'tx':
+ tx = True
+
+ ksft_eq(q['xsk'], {})
+ else:
+ if 'xsk' in q:
+ _fail("Check failed: xsk attribute set.")
+
+ ksft_eq(rx, True)
+ ksft_eq(tx, True)

def get_queues(cfg, nl) -> None:
snl = NetdevFamily(recv_size=4096)
@@ -81,7 +112,7 @@ def check_down(cfg, nl) -> None:

def main() -> None:
with NetDrvEnv(__file__, queue_count=100) as cfg:
- ksft_run([get_queues, addremove_queues, check_down], args=(cfg, NetdevFamily()))
+ ksft_run([get_queues, addremove_queues, check_down, check_xdp], args=(cfg, NetdevFamily()))
ksft_exit()

diff --git a/tools/testing/selftests/drivers/net/xdp_helper.c b/tools/testing/selftests/drivers/net/xdp_helper.c
new file mode 100644
index 000000000000..b04d4e0ea30a
--- /dev/null
+++ b/tools/testing/selftests/drivers/net/xdp_helper.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <linux/if_xdp.h>
+#include <linux/if_link.h>
+#include <net/if.h>
+#include <inttypes.h>
+
+#define UMEM_SZ (1U << 16)
+#define NUM_DESC (UMEM_SZ / 2048)
+
+/* this is a simple helper program that creates an XDP socket and does the
+ * minimum necessary to get bind() to succeed.
+ *
+ * this test program is not intended to actually process packets, but could be
+ * extended in the future if that is actually needed.
+ *
+ * it is used by queues.py to ensure the xsk netlinux attribute is set
+ * correctly.
+ */
+int main(int argc, char **argv)
+{
+ struct xdp_umem_reg umem_reg = { 0 };
+ struct sockaddr_xdp sxdp = { 0 };
+ int num_desc = NUM_DESC;
+ void *umem_area;
+ int ifindex;
+ int sock_fd;
+ int queue;
+ char byte;
+
+ if (argc != 3) {
+ fprintf(stderr, "Usage: %s ifindex queue_id", argv[0]);
+ return 1;
+ }
+
+ sock_fd = socket(AF_XDP, SOCK_RAW, 0);
+ if (sock_fd < 0) {
+ perror("socket creation failed");
+ return 1;
+ }
+
+ ifindex = atoi(argv[1]);
+ queue = atoi(argv[2]);
+
+ umem_area = mmap(NULL, UMEM_SZ, PROT_READ | PROT_WRITE, MAP_PRIVATE |
+ MAP_ANONYMOUS, -1, 0);
+ if (umem_area == MAP_FAILED)
+ return -1;
+
+ umem_reg.addr = (uintptr_t)umem_area;
+ umem_reg.len = UMEM_SZ;
+ umem_reg.chunk_size = 2048;
+ umem_reg.headroom = 0;
+
+ setsockopt(sock_fd, SOL_XDP, XDP_UMEM_REG, &umem_reg,
+ sizeof(umem_reg));
+ setsockopt(sock_fd, SOL_XDP, XDP_UMEM_FILL_RING, &num_desc,
+ sizeof(num_desc));
+ setsockopt(sock_fd, SOL_XDP, XDP_UMEM_COMPLETION_RING, &num_desc,
+ sizeof(num_desc));
+ setsockopt(sock_fd, SOL_XDP, XDP_RX_RING, &num_desc, sizeof(num_desc));
+
+ sxdp.sxdp_family = AF_XDP;
+ sxdp.sxdp_ifindex = ifindex;
+ sxdp.sxdp_queue_id = queue;
+ sxdp.sxdp_flags = 0;
+
+ if (bind(sock_fd, (struct sockaddr *)&sxdp, sizeof(sxdp)) != 0) {
+ perror("bind failed");
+ close(sock_fd);
+ return 1;
+ }
+
+ /* give the parent program some data when the socket is ready*/
+ fprintf(stdout, "%d\n", sock_fd);
+
+ /* parent program will write a byte to stdin when its ready for this
+ * helper to exit
+ */
+ read(STDIN_FILENO, &byte, 1);
+
+ close(sock_fd);
+ return 0;
+}
--
2.43.0