From 81236c74dba6f4966d76c471ef4434846c2fc05c Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Sat, 27 Sep 2025 15:54:19 -0700 Subject: [PATCH] selftests: drv-net: psp: add test for auto-adjusting TCP MSS Test TCP MSS getting auto-adjusted. PSP adds an encapsulation overhead of 40B per packet, when used in transport mode without any virtualization cookie or other optional PSP header fields. The kernel should adjust the MSS for a connection after PSP tx state is reached. Signed-off-by: Jakub Kicinski Signed-off-by: Daniel Zahka Link: https://patch.msgid.link/20250927225420.1443468-8-kuba@kernel.org Reviewed-by: Willem de Bruijn Signed-off-by: Paolo Abeni --- tools/testing/selftests/drivers/net/psp.py | 52 ++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/tools/testing/selftests/drivers/net/psp.py b/tools/testing/selftests/drivers/net/psp.py index e8c80ebfa2f68..37953838abf8b 100755 --- a/tools/testing/selftests/drivers/net/psp.py +++ b/tools/testing/selftests/drivers/net/psp.py @@ -431,6 +431,45 @@ def data_send_disconnect(cfg): s.close() +def _data_mss_adjust(cfg, ipver): + _init_psp_dev(cfg) + + # First figure out what the MSS would be without any adjustments + s = _make_clr_conn(cfg, ipver) + s.send(b"0123456789abcdef" * 1024) + _check_data_rx(cfg, 16 * 1024) + mss = s.getsockopt(socket.IPPROTO_TCP, socket.TCP_MAXSEG) + _close_conn(cfg, s) + + s = _make_psp_conn(cfg, 0, ipver) + try: + rx_assoc = cfg.pspnl.rx_assoc({"version": 0, + "dev-id": cfg.psp_dev_id, + "sock-fd": s.fileno()}) + rx = rx_assoc['rx-key'] + tx = _spi_xchg(s, rx) + + rxmss = s.getsockopt(socket.IPPROTO_TCP, socket.TCP_MAXSEG) + ksft_eq(mss, rxmss) + + cfg.pspnl.tx_assoc({"dev-id": cfg.psp_dev_id, + "version": 0, + "tx-key": tx, + "sock-fd": s.fileno()}) + + txmss = s.getsockopt(socket.IPPROTO_TCP, socket.TCP_MAXSEG) + ksft_eq(mss, txmss + 40) + + data_len = _send_careful(cfg, s, 100) + _check_data_rx(cfg, data_len) + _check_data_outq(s, 0) + + txmss = s.getsockopt(socket.IPPROTO_TCP, socket.TCP_MAXSEG) + ksft_eq(mss, txmss + 40) + finally: + _close_psp_conn(cfg, s) + + def data_stale_key(cfg): """ Test send on a double-rotated key """ _init_psp_dev(cfg) @@ -470,6 +509,15 @@ def psp_ip_ver_test_builder(name, test_func, psp_ver, ipver): return test_case +def ipver_test_builder(name, test_func, ipver): + """Build test cases for each IP version""" + def test_case(cfg): + cfg.require_ipver(ipver) + test_case.__name__ = f"{name}_ip{ipver}" + test_func(cfg, ipver) + return test_case + + def main() -> None: """ Ksft boiler plate main """ @@ -497,6 +545,10 @@ def main() -> None: for version in range(0, 4) for ipver in ("4", "6") ] + cases += [ + ipver_test_builder("data_mss_adjust", _data_mss_adjust, ipver) + for ipver in ("4", "6") + ] ksft_run(cases=cases, globs=globals(), case_pfx={"dev_", "data_", "assoc_"}, -- 2.47.3