dpp-nfc: Make handover request collision detection more robust

Wait up to 100 ms for own handover request transmission to succeed if
peer handover request is received, but own crn is not yet available.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

diff --git a/wpa_supplicant/examples/dpp-nfc.py b/wpa_supplicant/examples/dpp-nfc.py
index b82713832dae8e8a1bbf933eb4a1a86ee6f1551f..d9ae7475a69cb93cc4b750f13ee9965fb8b6cdf5 100755 (executable)
--- a/wpa_supplicant/examples/dpp-nfc.py
+++ b/wpa_supplicant/examples/dpp-nfc.py
@@ -34,6 +34,7 @@ continue_loop = True
 terminate_now = False
 summary_file = None
 success_file = None
+my_crn_ready = False
 my_crn = None
 peer_crn = None
 mutex = threading.Lock()
@@ -245,12 +246,15 @@ def dpp_handover_client(llc):
 
     summary("Sending handover request")
 
+    global my_crn, my_crn_ready
+    my_crn_ready = True
+
     if not client.send_records(message):
+        my_crn_ready = False
         summary("Failed to send handover request")
         client.close()
         return
 
-    global my_crn
     my_crn, = struct.unpack('>H', crn)
 
     summary("Receiving handover response")
@@ -357,7 +361,7 @@ class HandoverServer(nfc.handover.HandoverServer):
             print("\n")
         summary("HandoverServer - request received: " + str(records))
 
-        global my_crn, peer_crn
+        global my_crn, peer_crn, my_crn_ready
 
         for carrier in records:
             if not isinstance(carrier, ndef.HandoverRequestRecord):
@@ -366,6 +370,12 @@ class HandoverServer(nfc.handover.HandoverServer):
                 peer_crn = carrier.collision_resolution_number
                 summary("peer_crn: %d" % peer_crn)
 
+        if my_crn is None and my_crn_ready:
+            summary("Still trying to send own handover request - wait a moment to see if that succeeds before checking crn values")
+            for i in range(10):
+                if my_crn is not None:
+                    break
+                time.sleep(0.01)
         if my_crn is not None:
             summary("my_crn: %d" % my_crn)
 
@@ -635,8 +645,9 @@ def llcp_startup(llc):
 
 def llcp_connected(llc):
     summary("P2P LLCP connected")
-    global wait_connection, my_crn, peer_crn
+    global wait_connection, my_crn, peer_crn, my_crn_ready
     wait_connection = False
+    my_crn_ready = False
     my_crn = None
     peer_crn = None
     global srv