Re: [PATCH bpf-next v3 5/6] selftests/bpf: add test for XDP metadata support in tun driver

Am 24.02.25 um 18:14 schrieb Stanislav Fomichev:

On 02/24, Marcus Wichelmann wrote:

quoted

Add a selftest that creates a tap device, attaches XDP and TC programs,
writes a packet with a test payload into the tap device and checks the
test result. This test ensures that the XDP metadata support in the tun
driver is enabled and that the metadata size is correctly passed to the
skb.

See the previous commit ("selftests/bpf: refactor xdp_context_functional
test and bpf program") for details about the test design.

Signed-off-by: Marcus Wichelmann <redacted>
---
  .../bpf/prog_tests/xdp_context_test_run.c     | 64 +++++++++++++++++++
  1 file changed, 64 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
index 4043f220d7c0..60aad6bd8882 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c

@@ -8,6 +8,7 @@
  #define TX_NAME "veth1"
  #define TX_NETNS "xdp_context_tx"
  #define RX_NETNS "xdp_context_rx"
+#define TAP_NAME "tap0"
  
  #define TEST_PAYLOAD_LEN 32
  static const __u8 test_payload[TEST_PAYLOAD_LEN] = {

@@ -251,3 +252,66 @@ void test_xdp_context_veth(void)
  	netns_free(tx_ns);
  }
  
+void test_xdp_context_tuntap(void)

tap0 is already used by lwt tests, so there is a chance this new test
will clash with it? Should we run your new test in a net namespace
to be safe? Bastien recently added a change where you can make
your test run in a net ns by naming the function test_ns_xxx.

Ah, cool, I didn't know of that feature.

For reference, you probably mean this one?
commit c047e0e0e435 ("selftests/bpf: Optionally open a dedicated namespace to run test in it")

As long as the tests are not run in parallel, the test function SHOULD
clean up well enough behind itself that no conflicts should occur.
But having that bit of extra safety won't hurt.

Thanks!
Marcus