[PATCH 6/6] hwsim: Add hwsim test case for no_sta handling

[Ramasamy Kaliappan]

Add new hwsim test case(test_eht_mld_sae_two_links_sta_reconnect_no_sta)
to validate the no_sta handling in the authentication and association
frame.

The test configures a 3‑link AP MLD and an MLD‑capable STA, performs an
initial SAE-based MLO connection, and verifies expected MLD state and
link activity. It then triggers a reassociation without an explicit
disconnect to simulate a reconnect scenario where the AP may still hold
a station entry while receiving frames marked with no_sta.

A dedicated reconnect test verifies that an AP MLD preserves the STA
entry across reassociation while receiving no_sta-marked frames, and
that responses are sent to the correct destination after capability
updates. Traffic is validated across all links after reconnect.

These tests help to ensure correct infra-level behavior for frames
marked with NL80211_ATTR_FRAME_CMD_NO_STA, preventing regressions
in authentication, association, SA Query, and TX status processing
for multi-link setups.

Signed-off-by: Ramasamy Kaliappan <ramasamy.kaliappan at oss.qualcomm.com>
---
 tests/hwsim/test_eht.py | 63 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/tests/hwsim/test_eht.py b/tests/hwsim/test_eht.py
index 4ad464ddb017..8cbc9487ee44 100644
--- a/tests/hwsim/test_eht.py
+++ b/tests/hwsim/test_eht.py
@@ -689,6 +689,69 @@ def test_eht_mld_sae_two_links(dev, apdev):
     """EHT MLD AP with MLD client SAE H2E connection using two links"""
     run_eht_mld_sae_two_links(dev, apdev)
 
+def test_eht_mld_sae_two_links_sta_reconnect_no_sta(dev, apdev):
+    """EHT AP MLD with MLD STA reconnecting while AP still has STA (no_sta handling)"""
+    with HWSimRadio(use_mlo=True) as (hapd_radio, hapd_iface), \
+        HWSimRadio(use_mlo=True) as (wpas_radio, wpas_iface):
+
+        wpas = WpaSupplicant(global_iface='/tmp/wpas-wlan5')
+        wpas.interface_add(wpas_iface)
+        check_sae_capab(wpas)
+
+        passphrase = 'qwertyuiop'
+        ssid = "mld_ap_sae_two_link_reconnect"
+
+        params = eht_mld_ap_wpa2_params(ssid, passphrase,
+                                        key_mgmt="SAE", mfp="2", pwe="1")
+
+        hapd0 = eht_mld_enable_ap(hapd_iface, 0, params)
+
+        params1 = dict(params)
+        params1['channel'] = '6'
+        hapd1 = eht_mld_enable_ap(hapd_iface, 1, params1)
+
+        try:
+            wpas.set("sae_pwe", "1")
+            wpas.set("sae_groups", "20 19")
+
+            # Initial MLO connection
+            wpas.connect(ssid, sae_password=passphrase,
+                         scan_freq="2412 2437",
+                         key_mgmt="SAE", ieee80211w="2", beacon_prot="1")
+
+            eht_verify_status(wpas, hapd0, 2412, 20, is_ht=True, mld=True,
+                              valid_links=3, active_links=3)
+            eht_verify_wifi_version(wpas)
+            if wpas.get_status_field('sae_group') != '19':
+                raise Exception("Initial SAE group not as expected")
+
+            sta = hapd0.get_sta(wpas.own_addr())
+            logger.info("MLD STA after first assoc at hapd0: " + str(sta))
+            if sta['addr'] == 'FAIL':
+                raise Exception("AP MLD did not create STA entry after first association")
+
+            traffic_test(wpas, hapd0)
+            traffic_test(wpas, hapd1)
+
+            # Reconnect (reassociate) without explicit disconnect from the test
+            time.sleep(1)
+            wpas.request("REASSOCIATE")
+            ev = wpas.wait_event(["CTRL-EVENT-CONNECTED"], timeout=10)
+            if ev is None:
+                raise Exception("Reassociation did not complete")
+
+            # AP should still have a STA entry for this MLD STA
+            sta2 = hapd0.get_sta(wpas.own_addr())
+            logger.info("MLD STA after reassoc at hapd0: " + str(sta2))
+            if sta2['addr'] == 'FAIL':
+                raise Exception("AP MLD lost STA entry on reassociation")
+
+            traffic_test(wpas, hapd0)
+            traffic_test(wpas, hapd1)
+        finally:
+            wpas.set("sae_pwe", "0")
+            wpas.set("sae_groups", "")
+
 def test_eht_mld_sae_two_links_no_beacon_prot(dev, apdev):
     """EHT MLD AP with MLD client SAE H2E connection using two links and no beacon protection"""
     run_eht_mld_sae_two_links(dev, apdev, beacon_prot="0")
-- 
2.34.1