dpp-nfc: Fix connection handover renegotiation

The use of the alternative channel list did not work properly for the
case were both ends were trying to initiate the negotiated connection
handover. Fix this by always starting a new connection handover client
thread for sending the alternative proposal and ignoring peer messages
(likely something from the first attempt) during this modified attempt.

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 5230dc59dde41e5c69147b4363ede718c6cbfe0f..3281ca6062b88b1fead762f0c1aff92a03f3f7a2 100755 (executable)
--- a/wpa_supplicant/examples/dpp-nfc.py
+++ b/wpa_supplicant/examples/dpp-nfc.py
@@ -241,7 +241,7 @@ def dpp_handover_client(llc, alt=False):
     summary("NFC Handover Request message for DPP: " + str(message))
 
     global peer_crn
-    if peer_crn is not None:
+    if peer_crn is not None and not alt:
         summary("NFC handover request from peer was already received - do not send own")
         return
     client = nfc.handover.HandoverClient(llc)
@@ -258,7 +258,7 @@ def dpp_handover_client(llc, alt=False):
         client.close()
         return
 
-    if peer_crn is not None:
+    if peer_crn is not None and not alt:
         summary("NFC handover request from peer was already received - do not send own")
         client.close()
         return
@@ -507,18 +507,17 @@ class HandoverServer(nfc.handover.HandoverServer):
                 sel = [hs, carrier]
                 break
 
+        global hs_sent
         summary("Sending handover select: " + str(sel))
         if found:
             summary("Handover completed successfully")
             self.success = True
+            hs_sent = True
         else:
             summary("Try to initiate with alternative parameters")
             self.try_own = True
-            if not init_on_touch and no_input:
-                # Need to start client thread now
-                threading.Thread(target=llcp_worker, args=(self.llc,)).start()
-        global hs_sent
-        hs_sent = True
+            hs_sent = False
+            threading.Thread(target=llcp_worker, args=(self.llc, True)).start()
         return sel
 
 def clear_raw_mode():
@@ -651,12 +650,18 @@ def rdwr_connected(tag):
 
     return not no_wait
 
-def llcp_worker(llc):
+def llcp_worker(llc, try_alt):
+    print("Start of llcp_worker()")
+    if try_alt:
+        summary("Starting handover client (try_alt)")
+        dpp_handover_client(llc, alt=True)
+        summary("Exiting llcp_worker thread (try_alt)")
+        return
     global init_on_touch
     if init_on_touch:
-        summary("Starting handover client")
+        summary("Starting handover client (init_on_touch)")
         dpp_handover_client(llc)
-        summary("Exiting llcp_worker thread (init_in_touch)")
+        summary("Exiting llcp_worker thread (init_on_touch)")
         return
 
     global no_input
@@ -716,7 +721,7 @@ def llcp_connected(llc):
     global srv
     srv.start()
     if init_on_touch or not no_input:
-        threading.Thread(target=llcp_worker, args=(llc,)).start()
+        threading.Thread(target=llcp_worker, args=(llc, False)).start()
     return True
 
 def llcp_release(llc):