hostapd/wps-ap-nfc.py

   1 #!/usr/bin/python
   2 #
   3 # Example nfcpy to hostapd 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/hostapd'
  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 hostapd: ", error
  32             return None
  33
  34     if len(ifaces) < 1:
  35         print "No hostapd 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_config_token():
  56     wpas = wpas_connect()
  57     if (wpas == None):
  58         return None
  59     return wpas.request("WPS_NFC_CONFIG_TOKEN NDEF").rstrip().decode("hex")
  60
  61
  62 def wpas_get_password_token():
  63     wpas = wpas_connect()
  64     if (wpas == None):
  65         return None
  66     return wpas.request("WPS_NFC_TOKEN NDEF").rstrip().decode("hex")
  67
  68
  69 def wpas_get_handover_sel():
  70     wpas = wpas_connect()
  71     if (wpas == None):
  72         return None
  73     return wpas.request("NFC_GET_HANDOVER_SEL NDEF WPS-CR").rstrip().decode("hex")
  74
  75
  76 def wpas_report_handover(req, sel):
  77     wpas = wpas_connect()
  78     if (wpas == None):
  79         return None
  80     return wpas.request("NFC_REPORT_HANDOVER RESP WPS " +
  81                         str(req).encode("hex") + " " +
  82                         str(sel).encode("hex"))
  83
  84
  85 class HandoverServer(nfc.handover.HandoverServer):
  86     def __init__(self):
  87         super(HandoverServer, self).__init__()
  88
  89     def process_request(self, request):
  90         print "HandoverServer - request received"
  91         print "Parsed handover request: " + request.pretty()
  92
  93         sel = nfc.ndef.HandoverSelectMessage(version="1.2")
  94
  95         for carrier in request.carriers:
  96             print "Remote carrier type: " + carrier.type
  97             if carrier.type == "application/vnd.wfa.wsc":
  98                 print "WPS carrier type match - add WPS carrier record"
  99                 self.received_carrier = carrier.record
 100                 data = wpas_get_handover_sel()
 101                 if data is None:
 102                     print "Could not get handover select carrier record from hostapd"
 103                     continue
 104                 print "Handover select carrier record from hostapd:"
 105                 print data.encode("hex")
 106                 self.sent_carrier = data
 107
 108                 message = nfc.ndef.Message(data);
 109                 sel.add_carrier(message[0], "active", message[1:])
 110
 111         print "Handover select:"
 112         print sel.pretty()
 113         print str(sel).encode("hex")
 114
 115         print "Sending handover select"
 116         return sel
 117
 118
 119 def wps_handover_resp(peer):
 120     print "Trying to handle WPS handover"
 121
 122     srv = HandoverServer()
 123     srv.sent_carrier = None
 124
 125     nfc.llcp.activate(peer);
 126
 127     try:
 128         print "Trying handover";
 129         srv.start()
 130         print "Wait for disconnect"
 131         while nfc.llcp.connected():
 132             time.sleep(0.1)
 133         print "Disconnected after handover"
 134     except nfc.llcp.ConnectRefused:
 135         print "Handover connection refused"
 136         nfc.llcp.shutdown()
 137         return
 138
 139     if srv.sent_carrier:
 140         wpas_report_handover(srv.received_carrier, srv.sent_carrier)
 141
 142     print "Remove peer"
 143     nfc.llcp.shutdown()
 144     print "Done with handover"
 145
 146
 147 def wps_tag_read(tag):
 148     if len(tag.ndef.message):
 149         message = nfc.ndef.Message(tag.ndef.message)
 150         print "message type " + message.type
 151
 152         for record in message:
 153             print "record type " + record.type
 154             if record.type == "application/vnd.wfa.wsc":
 155                 print "WPS tag - send to hostapd"
 156                 wpas_tag_read(tag.ndef.message)
 157                 break
 158     else:
 159         print "Empty tag"
 160
 161     print "Remove tag"
 162     while tag.is_present:
 163         time.sleep(0.1)
 164
 165
 166 def wps_write_config_tag(clf):
 167     print "Write WPS config token"
 168     data = wpas_get_config_token()
 169     if (data == None):
 170         print "Could not get WPS config token from hostapd"
 171         return
 172
 173     print "Touch an NFC tag"
 174     while True:
 175         tag = clf.poll()
 176         if tag == None:
 177             time.sleep(0.1)
 178             continue
 179         break
 180
 181     print "Tag found - writing"
 182     tag.ndef.message = data
 183     print "Done - remove tag"
 184     while tag.is_present:
 185         time.sleep(0.1)
 186
 187
 188 def wps_write_password_tag(clf):
 189     print "Write WPS password token"
 190     data = wpas_get_password_token()
 191     if (data == None):
 192         print "Could not get WPS password token from hostapd"
 193         return
 194
 195     print "Touch an NFC tag"
 196     while True:
 197         tag = clf.poll()
 198         if tag == None:
 199             time.sleep(0.1)
 200             continue
 201         break
 202
 203     print "Tag found - writing"
 204     tag.ndef.message = data
 205     print "Done - remove tag"
 206     while tag.is_present:
 207         time.sleep(0.1)
 208
 209
 210 def find_peer(clf):
 211     while True:
 212         if nfc.llcp.connected():
 213             print "LLCP connected"
 214         general_bytes = nfc.llcp.startup({})
 215         peer = clf.listen(ord(os.urandom(1)) + 250, general_bytes)
 216         if isinstance(peer, nfc.DEP):
 217             print "listen -> DEP";
 218             if peer.general_bytes.startswith("Ffm"):
 219                 print "Found DEP"
 220                 return peer
 221             print "mismatch in general_bytes"
 222             print peer.general_bytes
 223
 224         peer = clf.poll(general_bytes)
 225         if isinstance(peer, nfc.DEP):
 226             print "poll -> DEP";
 227             if peer.general_bytes.startswith("Ffm"):
 228                 print "Found DEP"
 229                 return peer
 230             print "mismatch in general_bytes"
 231             print peer.general_bytes
 232
 233         if peer:
 234             print "Found tag"
 235             return peer
 236
 237
 238 def main():
 239     clf = nfc.ContactlessFrontend()
 240
 241     try:
 242         if len(sys.argv) > 1 and sys.argv[1] == "write-config":
 243             wps_write_config_tag(clf)
 244             raise SystemExit
 245
 246         if len(sys.argv) > 1 and sys.argv[1] == "write-password":
 247             wps_write_password_tag(clf)
 248             raise SystemExit
 249
 250         while True:
 251             print "Waiting for a tag or peer to be touched"
 252
 253             tag = find_peer(clf)
 254             if isinstance(tag, nfc.DEP):
 255                 wps_handover_resp(tag)
 256                 continue
 257
 258             if tag.ndef:
 259                 wps_tag_read(tag)
 260                 continue
 261
 262             print "Not an NDEF tag - remove tag"
 263             while tag.is_present:
 264                 time.sleep(0.1)
 265
 266     except KeyboardInterrupt:
 267         raise SystemExit
 268     finally:
 269         clf.close()
 270
 271     raise SystemExit
 272
 273 if __name__ == '__main__':
 274     main()