tests: Add test to check disconnect in powersave

The kernel had two bugs (one in hwsim and one more important one in
mac80211) in this area, add a test to make sure we can disconnect
without any kernel issues while in powersave.

Also make sure that the TIM bit gets set and cleared again (by checking
with tshark.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

tests/hwsim/hwsim_utils.py

@@ -150,3 +150,11 @@ def test_connectivity_p2p_sta(dev1, dev2, dscp=None, tos=None):
 
 def test_connectivity_sta(dev1, dev2, dscp=None, tos=None):
     test_connectivity(dev1, dev2, dscp, tos)
+
+(PS_DISABLED, PS_ENABLED, PS_AUTO_POLL, PS_MANUAL_POLL) = range(4)
+
+def set_powersave(dev, val):
+    phy = dev.get_driver_status_field("phyname")
+    psf = open('/sys/kernel/debug/ieee80211/%s/hwsim/ps' % phy, 'w')
+    psf.write('%d\n' % val)
+    psf.close()

tests/hwsim/test_ap_open.py

@@ -9,9 +9,11 @@ logger = logging.getLogger()
 import struct
 import subprocess
 import time
+import os
 
 import hostapd
 import hwsim_utils
+from tshark import run_tshark
 from utils import alloc_fail
 from wpasupplicant import WpaSupplicant
 
@@ -346,3 +348,45 @@ def test_ap_open_ifdown(dev, apdev):
         raise Exception("No INTERFACE-ENABLED event")
     dev[0].wait_connected()
     hwsim_utils.test_connectivity(dev[0], hapd)
+
+def test_ap_open_disconnect_in_ps(dev, apdev, params):
+    """Disconnect with the client in PS to regression-test a kernel bug"""
+    hapd = hostapd.add_ap(apdev[0]['ifname'], { "ssid": "open" })
+    dev[0].connect("open", key_mgmt="NONE", scan_freq="2412",
+                   bg_scan_period="0")
+    ev = hapd.wait_event([ "AP-STA-CONNECTED" ], timeout=5)
+    if ev is None:
+        raise Exception("No connection event received from hostapd")
+
+    time.sleep(0.2)
+    hwsim_utils.set_powersave(dev[0], hwsim_utils.PS_MANUAL_POLL)
+    try:
+        # inject some traffic
+        sa = hapd.own_addr()
+        da = dev[0].own_addr()
+        hapd.request('DATA_TEST_CONFIG 1')
+        hapd.request('DATA_TEST_TX {} {} 0'.format(da, sa))
+        hapd.request('DATA_TEST_CONFIG 0')
+
+        # let the AP send couple of Beacon frames
+        time.sleep(0.3)
+
+        # disconnect - with traffic pending - shouldn't cause kernel warnings
+        dev[0].request("DISCONNECT")
+    finally:
+        hwsim_utils.set_powersave(dev[0], hwsim_utils.PS_DISABLED)
+
+    time.sleep(0.2)
+    out = run_tshark(os.path.join(params['logdir'], "hwsim0.pcapng"),
+                     "wlan_mgt.tim.partial_virtual_bitmap",
+                     ["wlan_mgt.tim.partial_virtual_bitmap"])
+    if out is not None:
+        state = 0
+        for l in out.splitlines():
+            pvb = int(l, 16)
+            if pvb > 0 and state == 0:
+                state = 1
+            elif pvb == 0 and state == 1:
+                state = 2
+        if state != 2:
+            raise Exception("Didn't observe TIM bit getting set and unset (state=%d)" % state)