wpa_supplicant/examples/wps-nfc.py

   1 #!/usr/bin/python
   2 #
   3 # Example nfcpy to wpa_supplicant wrapper for WPS NFC operations
   4 # Copyright (c) 2012-2013, Jouni Malinen <j@w1.fi>
   5 #
   6 # This software may be distributed under the terms of the BSD license.
   7 # See README for more details.
   8
   9 import os
  10 import sys
  11 import time
  12
  13 import nfc
  14 import nfc.ndef
  15 import nfc.llcp
  16 import nfc.handover
  17
  18 import logging
  19 logging.basicConfig()
  20
  21 import wpactrl
  22
  23 wpas_ctrl = '/var/run/wpa_supplicant'
  24
  25 def wpas_connect():
  26     ifaces = []
  27     if os.path.isdir(wpas_ctrl):
  28         try:
  29             ifaces = [os.path.join(wpas_ctrl, i) for i in os.listdir(wpas_ctrl)]
  30         except OSError, error:
  31             print "Could not find wpa_supplicant: ", error
  32             return None
  33
  34     if len(ifaces) < 1:
  35         print "No wpa_supplicant control interface found"
  36         return None
  37
  38     for ctrl in ifaces:
  39         try:
  40             wpas = wpactrl.WPACtrl(ctrl)
  41             return wpas
  42         except wpactrl.error, error:
  43             print "Error: ", error
  44             pass
  45     return None
  46
  47
  48 def wpas_tag_read(message):
  49     wpas = wpas_connect()
  50     if (wpas == None):
  51         return
  52     print wpas.request("WPS_NFC_TAG_READ " + message.encode("hex"))
  53
  54
  55 def wpas_get_handover_req():
  56     wpas = wpas_connect()
  57     if (wpas == None):
  58         return None
  59     return wpas.request("NFC_GET_HANDOVER_REQ NDEF WPS").rstrip().decode("hex")
  60
  61
  62 def wpas_put_handover_sel(message):
  63     wpas = wpas_connect()
  64     if (wpas == None):
  65         return
  66     print wpas.request("NFC_RX_HANDOVER_SEL " + str(message).encode("hex"))
  67
  68
  69 def wps_handover_init(peer):
  70     print "Trying to initiate WPS handover"
  71
  72     data = wpas_get_handover_req()
  73     if (data == None):
  74         print "Could not get handover request message from wpa_supplicant"
  75         return
  76     print "Handover request from wpa_supplicant: " + data.encode("hex")
  77     message = nfc.ndef.Message(data)
  78     print "Parsed handover request: " + message.pretty()
  79
  80     nfc.llcp.activate(peer);
  81
  82     client = nfc.handover.HandoverClient()
  83     try:
  84         print "Trying handover";
  85         client.connect()
  86         print "Connected for handover"
  87     except nfc.llcp.ConnectRefused:
  88         print "Handover connection refused"
  89         nfc.llcp.shutdown()
  90         client.close()
  91         return
  92
  93     print "Sending handover request"
  94
  95     if not client.send(message):
  96         print "Failed to send handover request"
  97
  98     print "Receiving handover response"
  99     message = client._recv()
 100     print "Handover select received"
 101     print message.pretty()
 102     wpas_put_handover_sel(message)
 103
 104     print "Remove peer"
 105     nfc.llcp.shutdown()
 106     client.close()
 107     print "Done with handover"
 108
 109
 110 def wps_tag_read(tag):
 111     if len(tag.ndef.message):
 112         message = nfc.ndef.Message(tag.ndef.message)
 113         print "message type " + message.type
 114
 115         for record in message:
 116             print "record type " + record.type
 117             if record.type == "application/vnd.wfa.wsc":
 118                 print "WPS tag - send to wpa_supplicant"
 119                 wpas_tag_read(tag.ndef.message)
 120                 break
 121     else:
 122         print "Empty tag"
 123
 124     print "Remove tag"
 125     while tag.is_present:
 126         time.sleep(0.1)
 127
 128
 129 def find_peer(clf):
 130     while True:
 131         if nfc.llcp.connected():
 132             print "LLCP connected"
 133         general_bytes = nfc.llcp.startup({})
 134         peer = clf.listen(ord(os.urandom(1)) + 200, general_bytes)
 135         if isinstance(peer, nfc.DEP):
 136             print "listen -> DEP";
 137             if peer.general_bytes.startswith("Ffm"):
 138                 print "Found DEP"
 139                 return peer
 140             print "mismatch in general_bytes"
 141             print peer.general_bytes
 142
 143         peer = clf.poll(general_bytes)
 144         if isinstance(peer, nfc.DEP):
 145             print "poll -> DEP";
 146             if peer.general_bytes.startswith("Ffm"):
 147                 print "Found DEP"
 148                 return peer
 149             print "mismatch in general_bytes"
 150             print peer.general_bytes
 151
 152         if peer:
 153             print "Found tag"
 154             return peer
 155
 156
 157 def main():
 158     clf = nfc.ContactlessFrontend()
 159
 160     try:
 161         while True:
 162             print "Waiting for a tag or peer to be touched"
 163
 164             tag = find_peer(clf)
 165             if isinstance(tag, nfc.DEP):
 166                 wps_handover_init(tag)
 167                 continue
 168
 169             if tag.ndef:
 170                 wps_tag_read(tag)
 171                 continue
 172
 173             print "Not an NDEF tag - remove tag"
 174             while tag.is_present:
 175                 time.sleep(0.1)
 176
 177     except KeyboardInterrupt:
 178         raise SystemExit
 179     finally:
 180         clf.close()
 181
 182     raise SystemExit
 183
 184 if __name__ == '__main__':
 185     main()