WPS: Add an example python script for NFC operations with hostapd

wps-ap-nfc.py uses nfcpy and python-wpactrl to support NFC operations
with hostapd for WPS operations.

Signed-hostap: Jouni Malinen <j@w1.fi>

hostapd/wps-ap-nfc.py

@@ -0,0 +1,228 @@
+#!/usr/bin/python
+#
+# Example nfcpy to hostapd wrapper for WPS NFC operations
+# Copyright (c) 2012-2013, Jouni Malinen <j@w1.fi>
+#
+# This software may be distributed under the terms of the BSD license.
+# See README for more details.
+
+import os
+import sys
+import time
+
+import nfc
+import nfc.ndef
+import nfc.llcp
+import nfc.handover
+
+import wpactrl
+
+wpas_ctrl = '/var/run/hostapd'
+
+def wpas_connect():
+    ifaces = []
+    if os.path.isdir(wpas_ctrl):
+        try:
+            ifaces = [os.path.join(wpas_ctrl, i) for i in os.listdir(wpas_ctrl)]
+        except OSError, error:
+            print "Could not find hostapd: ", error
+            return None
+
+    if len(ifaces) < 1:
+        print "No hostapd control interface found"
+        return None
+
+    for ctrl in ifaces:
+        try:
+            wpas = wpactrl.WPACtrl(ctrl)
+            return wpas
+        except wpactrl.error, error:
+            print "Error: ", error
+            pass
+    return None
+
+
+def wpas_tag_read(message):
+    wpas = wpas_connect()
+    if (wpas == None):
+        return
+    print wpas.request("WPS_NFC_TAG_READ " + message.encode("hex"))
+
+
+def wpas_get_config_token():
+    wpas = wpas_connect()
+    if (wpas == None):
+        return None
+    return wpas.request("WPS_NFC_CONFIG_TOKEN NDEF").rstrip().decode("hex")
+
+
+def wpas_get_password_token():
+    wpas = wpas_connect()
+    if (wpas == None):
+        return None
+    return wpas.request("WPS_NFC_TOKEN NDEF").rstrip().decode("hex")
+
+
+def wpas_get_handover_req():
+    wpas = wpas_connect()
+    if (wpas == None):
+        return None
+    return wpas.request("NFC_GET_HANDOVER_REQ NDEF WPS").rstrip().decode("hex")
+
+
+def wpas_put_handover_sel(message):
+    wpas = wpas_connect()
+    if (wpas == None):
+        return
+    print wpas.request("NFC_RX_HANDOVER_SEL " + str(message).encode("hex"))
+
+
+def wps_handover_init(peer):
+    print "Trying to initiate WPS handover"
+
+    data = wpas_get_handover_req()
+    if (data == None):
+        print "Could not get handover request message from hostapd"
+        return
+    print "Handover request from hostapd: " + data.encode("hex")
+    message = nfc.ndef.Message(data)
+    print "Parsed handover request: " + message.pretty()
+
+    nfc.llcp.activate(peer);
+    time.sleep(0.5)
+
+    client = nfc.handover.HandoverClient()
+    try:
+        print "Trying handover";
+        client.connect()
+        print "Connected for handover"
+    except nfc.llcp.ConnectRefused:
+        print "Handover connection refused"
+        nfc.llcp.shutdown()
+        client.close()
+        return
+
+    print "Sending handover request"
+
+    if not client.send(message):
+        print "Failed to send handover request"
+
+    print "Receiving handover response"
+    message = client._recv()
+    print "Handover select received"
+    print message.pretty()
+    wpas_put_handover_sel(message)
+
+    print "Remove peer"
+    nfc.llcp.shutdown()
+    client.close()
+    print "Done with handover"
+
+
+def wps_tag_read(tag):
+    if len(tag.ndef.message):
+        message = nfc.ndef.Message(tag.ndef.message)
+        print "message type " + message.type
+
+        for record in message:
+            print "record type " + record.type
+            if record.type == "application/vnd.wfa.wsc":
+                print "WPS tag - send to hostapd"
+                wpas_tag_read(tag.ndef.message)
+                break
+    else:
+        print "Empty tag"
+
+    print "Remove tag"
+    while tag.is_present:
+        time.sleep(0.1)
+
+
+def wps_write_config_tag(clf):
+    print "Write WPS config token"
+    data = wpas_get_config_token()
+    if (data == None):
+        print "Could not get WPS config token from hostapd"
+        return
+
+    print "Touch an NFC tag"
+    while True:
+        tag = clf.poll()
+        if tag == None:
+            time.sleep(0.1)
+            continue
+        break
+
+    print "Tag found - writing"
+    tag.ndef.message = data
+    print "Done - remove tag"
+    while tag.is_present:
+        time.sleep(0.1)
+
+
+def wps_write_password_tag(clf):
+    print "Write WPS password token"
+    data = wpas_get_password_token()
+    if (data == None):
+        print "Could not get WPS password token from hostapd"
+        return
+
+    print "Touch an NFC tag"
+    while True:
+        tag = clf.poll()
+        if tag == None:
+            time.sleep(0.1)
+            continue
+        break
+
+    print "Tag found - writing"
+    tag.ndef.message = data
+    print "Done - remove tag"
+    while tag.is_present:
+        time.sleep(0.1)
+
+
+def main():
+    clf = nfc.ContactlessFrontend()
+
+    try:
+        if len(sys.argv) > 1 and sys.argv[1] == "write-config":
+            wps_write_config_tag(clf)
+            raise SystemExit
+
+        if len(sys.argv) > 1 and sys.argv[1] == "write-password":
+            wps_write_password_tag(clf)
+            raise SystemExit
+
+        while True:
+            print "Waiting for a tag or peer to be touched"
+
+            while True:
+                general_bytes = nfc.llcp.startup({})
+                tag = clf.poll(general_bytes)
+                if tag == None:
+                    continue
+
+                if isinstance(tag, nfc.DEP):
+                    wps_handover_init(tag)
+                    break
+
+                if tag.ndef:
+                    wps_tag_read(tag)
+                    break
+
+                if tag:
+                    print "Not an NDEF tag - remove tag"
+                    while tag.is_present:
+                        time.sleep(0.1)
+                    break
+
+    except KeyboardInterrupt:
+        raise SystemExit
+    finally:
+        clf.close()
+
+    raise SystemExit
+
+if __name__ == '__main__':
+    main()