dpp-nfc: Fix handover client wait for receiving handover select

This was supposed to wait for up to 3.0 seconds for the handover select,
but the incorrect loop terminated ended up limiting this to a single
iteration of 0.1 second wait. This was too fast for some cases like the
AP mode operation where it may take significant time to enable the radio
for listening to DPP authentication messages.

Fix the loop to allow that full three second wait for the response to be
used. In addition, report the amount of time it takes to receive the
response.

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

wpa_supplicant/examples/dpp-nfc.py

@@ -278,8 +278,15 @@ class HandoverClient(nfc.handover.HandoverClient):
     def recv_octets(self, timeout=None):
         start = time.time()
         msg = bytearray()
-        poll_timeout = 0.1 if timeout is None or timeout > 0.1 else timeout
-        while self.socket.poll('recv', poll_timeout):
+        while True:
+            poll_timeout = 0.1 if timeout is None or timeout > 0.1 else timeout
+            if self.socket.poll('recv', poll_timeout) is None:
+                if timeout:
+                    timeout -= time.time() - start
+                    if timeout <= 0:
+                        return None
+                    start = time.time()
+                continue
             try:
                 r = self.socket.recv()
                 if r is None:
@@ -372,7 +379,10 @@ def run_dpp_handover_client(handover, alt=False):
 
     summary("Receiving handover response")
     try:
+        start = time.time()
         message = client.recv_records(timeout=3.0)
+        end = time.time()
+        summary("Received {} record(s) in {} seconds".format(len(message) if message is not None else -1, end - start))
     except Exception as e:
         # This is fine if we are the handover selector
         if handover.hs_sent: