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 import random
  13 import StringIO
  14
  15 import nfc
  16 import nfc.ndef
  17 import nfc.llcp
  18 import nfc.handover
  19
  20 import logging
  21 logging.basicConfig()
  22
  23 import wpactrl
  24
  25 wpas_ctrl = '/var/run/wpa_supplicant'
  26
  27 def wpas_connect():
  28     ifaces = []
  29     if os.path.isdir(wpas_ctrl):
  30         try:
  31             ifaces = [os.path.join(wpas_ctrl, i) for i in os.listdir(wpas_ctrl)]
  32         except OSError, error:
  33             print "Could not find wpa_supplicant: ", error
  34             return None
  35
  36     if len(ifaces) < 1:
  37         print "No wpa_supplicant control interface found"
  38         return None
  39
  40     for ctrl in ifaces:
  41         try:
  42             wpas = wpactrl.WPACtrl(ctrl)
  43             return wpas
  44         except wpactrl.error, error:
  45             print "Error: ", error
  46             pass
  47     return None
  48
  49
  50 def wpas_tag_read(message):
  51     wpas = wpas_connect()
  52     if (wpas == None):
  53         return
  54     print wpas.request("WPS_NFC_TAG_READ " + message.encode("hex"))
  55
  56
  57 def wpas_get_config_token():
  58     wpas = wpas_connect()
  59     if (wpas == None):
  60         return None
  61     return wpas.request("WPS_NFC_CONFIG_TOKEN NDEF").rstrip().decode("hex")
  62
  63
  64 def wpas_get_password_token():
  65     wpas = wpas_connect()
  66     if (wpas == None):
  67         return None
  68     return wpas.request("WPS_NFC_TOKEN NDEF").rstrip().decode("hex")
  69
  70
  71 def wpas_get_handover_req():
  72     wpas = wpas_connect()
  73     if (wpas == None):
  74         return None
  75     return wpas.request("NFC_GET_HANDOVER_REQ NDEF WPS-CR").rstrip().decode("hex")
  76
  77
  78 def wpas_report_handover(req, sel):
  79     wpas = wpas_connect()
  80     if (wpas == None):
  81         return None
  82     return wpas.request("NFC_REPORT_HANDOVER INIT WPS " +
  83                         str(req).encode("hex") + " " +
  84                         str(sel).encode("hex"))
  85
  86
  87 def wps_handover_init(peer):
  88     print "Trying to initiate WPS handover"
  89
  90     data = wpas_get_handover_req()
  91     if (data == None):
  92         print "Could not get handover request carrier record from wpa_supplicant"
  93         return
  94     print "Handover request carrier record from wpa_supplicant: " + data.encode("hex")
  95     record = nfc.ndef.Record()
  96     f = StringIO.StringIO(data)
  97     record._read(f)
  98     record = nfc.ndef.HandoverCarrierRecord(record)
  99     print "Parsed handover request carrier record:"
 100     print record.pretty()
 101
 102     message = nfc.ndef.HandoverRequestMessage(version="1.2")
 103     message.nonce = random.randint(0, 0xffff)
 104     message.add_carrier(record, "active")
 105
 106     print "Handover request:"
 107     print message.pretty()
 108
 109     nfc.llcp.activate(peer);
 110
 111     client = nfc.handover.HandoverClient()
 112     try:
 113         print "Trying handover";
 114         client.connect()
 115         print "Connected for handover"
 116     except nfc.llcp.ConnectRefused:
 117         print "Handover connection refused"
 118         nfc.llcp.shutdown()
 119         client.close()
 120         return
 121
 122     print "Sending handover request"
 123
 124     if not client.send(message):
 125         print "Failed to send handover request"
 126
 127     print "Receiving handover response"
 128     message = client._recv()
 129     if message is None:
 130         print "No response received"
 131         nfc.llcp.shutdown()
 132         client.close()
 133         return
 134     if message.type != "urn:nfc:wkt:Hs":
 135         print "Response was not Hs - received: " + message.type
 136         nfc.llcp.shutdown()
 137         client.close()
 138         return
 139
 140     print "Received message"
 141     print message.pretty()
 142     message = nfc.ndef.HandoverSelectMessage(message)
 143     print "Handover select received"
 144     print message.pretty()
 145
 146     for carrier in message.carriers:
 147         print "Remote carrier type: " + carrier.type
 148         if carrier.type == "application/vnd.wfa.wsc":
 149             print "WPS carrier type match - send to wpa_supplicant"
 150             wpas_report_handover(data, carrier.record)
 151             wifi = nfc.ndef.WifiConfigRecord(carrier.record)
 152             print wifi.pretty()
 153
 154     print "Remove peer"
 155     nfc.llcp.shutdown()
 156     client.close()
 157     print "Done with handover"
 158
 159
 160 def wps_tag_read(tag):
 161     if len(tag.ndef.message):
 162         message = nfc.ndef.Message(tag.ndef.message)
 163         print "message type " + message.type
 164
 165         for record in message:
 166             print "record type " + record.type
 167             if record.type == "application/vnd.wfa.wsc":
 168                 print "WPS tag - send to wpa_supplicant"
 169                 wpas_tag_read(tag.ndef.message)
 170                 break
 171     else:
 172         print "Empty tag"
 173
 174     print "Remove tag"
 175     while tag.is_present:
 176         time.sleep(0.1)
 177
 178
 179 def wps_write_config_tag(clf):
 180     print "Write WPS config token"
 181     data = wpas_get_config_token()
 182     if (data == None):
 183         print "Could not get WPS config token from wpa_supplicant"
 184         return
 185
 186     print "Touch an NFC tag"
 187     while True:
 188         tag = clf.poll()
 189         if tag == None:
 190             time.sleep(0.1)
 191             continue
 192         break
 193
 194     print "Tag found - writing"
 195     tag.ndef.message = data
 196     print "Done - remove tag"
 197     while tag.is_present:
 198         time.sleep(0.1)
 199
 200
 201 def wps_write_password_tag(clf):
 202     print "Write WPS password token"
 203     data = wpas_get_password_token()
 204     if (data == None):
 205         print "Could not get WPS password token from wpa_supplicant"
 206         return
 207
 208     print "Touch an NFC tag"
 209     while True:
 210         tag = clf.poll()
 211         if tag == None:
 212             time.sleep(0.1)
 213             continue
 214         break
 215
 216     print "Tag found - writing"
 217     tag.ndef.message = data
 218     print "Done - remove tag"
 219     while tag.is_present:
 220         time.sleep(0.1)
 221
 222
 223 def find_peer(clf):
 224     while True:
 225         if nfc.llcp.connected():
 226             print "LLCP connected"
 227         general_bytes = nfc.llcp.startup({})
 228         peer = clf.listen(ord(os.urandom(1)) + 250, general_bytes)
 229         if isinstance(peer, nfc.DEP):
 230             print "listen -> DEP";
 231             if peer.general_bytes.startswith("Ffm"):
 232                 print "Found DEP"
 233                 return peer
 234             print "mismatch in general_bytes"
 235             print peer.general_bytes
 236
 237         peer = clf.poll(general_bytes)
 238         if isinstance(peer, nfc.DEP):
 239             print "poll -> DEP";
 240             if peer.general_bytes.startswith("Ffm"):
 241                 print "Found DEP"
 242                 return peer
 243             print "mismatch in general_bytes"
 244             print peer.general_bytes
 245
 246         if peer:
 247             print "Found tag"
 248             return peer
 249
 250
 251 def main():
 252     clf = nfc.ContactlessFrontend()
 253
 254     try:
 255         if len(sys.argv) > 1 and sys.argv[1] == "write-config":
 256             wps_write_config_tag(clf)
 257             raise SystemExit
 258
 259         if len(sys.argv) > 1 and sys.argv[1] == "write-password":
 260             wps_write_password_tag(clf)
 261             raise SystemExit
 262
 263         while True:
 264             print "Waiting for a tag or peer to be touched"
 265
 266             tag = find_peer(clf)
 267             if isinstance(tag, nfc.DEP):
 268                 wps_handover_init(tag)
 269                 continue
 270
 271             if tag.ndef:
 272                 wps_tag_read(tag)
 273                 continue
 274
 275             print "Not an NDEF tag - remove tag"
 276             while tag.is_present:
 277                 time.sleep(0.1)
 278
 279     except KeyboardInterrupt:
 280         raise SystemExit
 281     finally:
 282         clf.close()
 283
 284     raise SystemExit
 285
 286 if __name__ == '__main__':
 287     main()