hostapd/wpa_supplicant/examples/wps-nfc.py

#!/usr/bin/python
#
# Example nfcpy to wpa_supplicant 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 random
import StringIO
import threading
import argparse

import nfc
import nfc.ndef
import nfc.llcp
import nfc.handover

import logging
logging.basicConfig()

import wpaspy

wpas_ctrl = '/var/run/wpa_supplicant'
srv = None
continue_loop = True

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 wpa_supplicant: ", error
            return None

    if len(ifaces) < 1:
        print "No wpa_supplicant control interface found"
        return None

    for ctrl in ifaces:
        try:
            wpas = wpaspy.Ctrl(ctrl)
            return wpas
        except Exception, e:
            pass
    return None


def wpas_tag_read(message):
    wpas = wpas_connect()
    if (wpas == None):
        return False
    if "FAIL" in wpas.request("WPS_NFC_TAG_READ " + str(message).encode("hex")):
        return False
    return True

def wpas_get_config_token(id=None):
    wpas = wpas_connect()
    if (wpas == None):
        return None
    if id:
        ret = wpas.request("WPS_NFC_CONFIG_TOKEN NDEF " + id)
    else:
        ret = wpas.request("WPS_NFC_CONFIG_TOKEN NDEF")
    if "FAIL" in ret:
        return None
    return ret.rstrip().decode("hex")


def wpas_get_er_config_token(uuid):
    wpas = wpas_connect()
    if (wpas == None):
        return None
    ret = wpas.request("WPS_ER_NFC_CONFIG_TOKEN NDEF " + uuid)
    if "FAIL" in ret:
        return None
    return ret.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-CR").rstrip().decode("hex")


def wpas_get_handover_sel(uuid):
    wpas = wpas_connect()
    if (wpas == None):
        return None
    if uuid is None:
        res = wpas.request("NFC_GET_HANDOVER_SEL NDEF WPS-CR").rstrip()
    else:
	res = wpas.request("NFC_GET_HANDOVER_SEL NDEF WPS-CR " + uuid).rstrip()
    if "FAIL" in res:
	return None
    return res.decode("hex")


def wpas_report_handover(req, sel, type):
    wpas = wpas_connect()
    if (wpas == None):
        return None
    return wpas.request("NFC_REPORT_HANDOVER " + type + " WPS " +
                        str(req).encode("hex") + " " +
                        str(sel).encode("hex"))


class HandoverServer(nfc.handover.HandoverServer):
    def __init__(self, llc):
        super(HandoverServer, self).__init__(llc)
        self.sent_carrier = None
        self.ho_server_processing = False
        self.success = False

    def process_request(self, request):
        self.ho_server_processing = True
        print "HandoverServer - request received"
        print "Parsed handover request: " + request.pretty()

        sel = nfc.ndef.HandoverSelectMessage(version="1.2")

        for carrier in request.carriers:
            print "Remote carrier type: " + carrier.type
            if carrier.type == "application/vnd.wfa.wsc":
                print "WPS carrier type match - add WPS carrier record"
                data = wpas_get_handover_sel(self.uuid)
                if data is None:
                    print "Could not get handover select carrier record from wpa_supplicant"
                    continue
                print "Handover select carrier record from wpa_supplicant:"
                print data.encode("hex")
                self.sent_carrier = data
                wpas_report_handover(carrier.record, self.sent_carrier, "RESP")

                message = nfc.ndef.Message(data);
                sel.add_carrier(message[0], "active", message[1:])

        print "Handover select:"
        print sel.pretty()
        print str(sel).encode("hex")

        print "Sending handover select"
        self.success = True
        return sel


def wps_handover_init(llc):
    print "Trying to initiate WPS handover"

    data = wpas_get_handover_req()
    if (data == None):
        print "Could not get handover request carrier record from wpa_supplicant"
        return
    print "Handover request carrier record from wpa_supplicant: " + data.encode("hex")
    record = nfc.ndef.Record()
    f = StringIO.StringIO(data)
    record._read(f)
    record = nfc.ndef.HandoverCarrierRecord(record)
    print "Parsed handover request carrier record:"
    print record.pretty()

    message = nfc.ndef.HandoverRequestMessage(version="1.2")
    message.nonce = random.randint(0, 0xffff)
    message.add_carrier(record, "active")

    print "Handover request:"
    print message.pretty()

    client = nfc.handover.HandoverClient(llc)
    try:
        print "Trying handover";
        client.connect()
        print "Connected for handover"
    except nfc.llcp.ConnectRefused:
        print "Handover connection refused"
        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()
    if message is None:
        print "No response received"
        client.close()
        return
    if message.type != "urn:nfc:wkt:Hs":
        print "Response was not Hs - received: " + message.type
        client.close()
        return

    print "Received message"
    print message.pretty()
    message = nfc.ndef.HandoverSelectMessage(message)
    print "Handover select received"
    print message.pretty()

    for carrier in message.carriers:
        print "Remote carrier type: " + carrier.type
        if carrier.type == "application/vnd.wfa.wsc":
            print "WPS carrier type match - send to wpa_supplicant"
            wpas_report_handover(data, carrier.record, "INIT")
            wifi = nfc.ndef.WifiConfigRecord(carrier.record)
            print wifi.pretty()

    print "Remove peer"
    client.close()
    print "Done with handover"
    global only_one
    if only_one:
        global continue_loop
        continue_loop = False


def wps_tag_read(tag, wait_remove=True):
    success = False
    if len(tag.ndef.message):
        for record in tag.ndef.message:
            print "record type " + record.type
            if record.type == "application/vnd.wfa.wsc":
                print "WPS tag - send to wpa_supplicant"
                success = wpas_tag_read(tag.ndef.message)
                break
    else:
        print "Empty tag"

    if wait_remove:
        print "Remove tag"
        while tag.is_present:
            time.sleep(0.1)

    return success


def rdwr_connected_write(tag):
    print "Tag found - writing"
    global write_data
    tag.ndef.message = str(write_data)
    print "Done - remove tag"
    global only_one
    if only_one:
        global continue_loop
        continue_loop = False
    global write_wait_remove
    while write_wait_remove and tag.is_present:
        time.sleep(0.1)

def wps_write_config_tag(clf, id=None, wait_remove=True):
    print "Write WPS config token"
    global write_data, write_wait_remove
    write_wait_remove = wait_remove
    write_data = wpas_get_config_token(id)
    if write_data == None:
        print "Could not get WPS config token from wpa_supplicant"
        sys.exit(1)
        return
    print "Touch an NFC tag"
    clf.connect(rdwr={'on-connect': rdwr_connected_write})


def wps_write_er_config_tag(clf, uuid, wait_remove=True):
    print "Write WPS ER config token"
    global write_data, write_wait_remove
    write_wait_remove = wait_remove
    write_data = wpas_get_er_config_token(uuid)
    if write_data == None:
        print "Could not get WPS config token from wpa_supplicant"
        return

    print "Touch an NFC tag"
    clf.connect(rdwr={'on-connect': rdwr_connected_write})


def wps_write_password_tag(clf, wait_remove=True):
    print "Write WPS password token"
    global write_data, write_wait_remove
    write_wait_remove = wait_remove
    write_data = wpas_get_password_token()
    if write_data == None:
        print "Could not get WPS password token from wpa_supplicant"
        return

    print "Touch an NFC tag"
    clf.connect(rdwr={'on-connect': rdwr_connected_write})


def rdwr_connected(tag):
    global only_one
    print "Tag connected: " + str(tag)

    if tag.ndef:
        print "NDEF tag: " + tag.type
        try:
            print tag.ndef.message.pretty()
        except Exception, e:
            print e
        success = wps_tag_read(tag, not only_one)
        if only_one and success:
            global continue_loop
            continue_loop = False
    else:
        print "Not an NDEF tag - remove tag"
        while tag.is_present:
            time.sleep(0.1)
    return True


def llcp_worker(llc):
    global arg_uuid
    if arg_uuid is None:
        wps_handover_init(llc)
        return

    global srv
    global wait_connection
    while not wait_connection and srv.sent_carrier is None:
        if srv.ho_server_processing:
            time.sleep(0.025)

def llcp_startup(clf, llc):
    global arg_uuid
    if arg_uuid:
        print "Start LLCP server"
        global srv
        srv = HandoverServer(llc)
        if arg_uuid is "ap":
            print "Trying to handle WPS handover"
            srv.uuid = None
        else:
            print "Trying to handle WPS handover with AP " + arg_uuid
            srv.uuid = arg_uuid
    return llc

def llcp_connected(llc):
    print "P2P LLCP connected"
    global wait_connection
    wait_connection = False
    global arg_uuid
    if arg_uuid:
        global srv
        srv.start()
    else:
        threading.Thread(target=llcp_worker, args=(llc,)).start()
    return True


def main():
    clf = nfc.ContactlessFrontend()

    parser = argparse.ArgumentParser(description='nfcpy to wpa_supplicant integration for WPS NFC operations')
    parser.add_argument('--only-one', '-1', action='store_true',
                        help='run only one operation and exit')
    parser.add_argument('--no-wait', action='store_true',
                        help='do not wait for tag to be removed before exiting')
    parser.add_argument('--uuid',
                        help='UUID of an AP (used for WPS ER operations)')
    parser.add_argument('--id',
                        help='network id (used for WPS ER operations)')
    parser.add_argument('command', choices=['write-config',
                                            'write-er-config',
                                            'write-password'],
                        nargs='?')
    args = parser.parse_args()

    global arg_uuid
    arg_uuid = args.uuid

    global only_one
    only_one = args.only_one

    try:
        if not clf.open("usb"):
            print "Could not open connection with an NFC device"
            raise SystemExit

        if args.command == "write-config":
            wps_write_config_tag(clf, id=args.id, wait_remove=not args.no_wait)
            raise SystemExit

        if args.command == "write-er-config":
            wps_write_er_config_tag(clf, args.uuid, wait_remove=not args.no_wait)
            raise SystemExit

        if args.command == "write-password":
            wps_write_password_tag(clf, wait_remove=not args.no_wait)
            raise SystemExit

        global continue_loop
        while continue_loop:
            print "Waiting for a tag or peer to be touched"
            wait_connection = True
            try:
                if not clf.connect(rdwr={'on-connect': rdwr_connected},
                                   llcp={'on-startup': llcp_startup,
                                         'on-connect': llcp_connected}):
                    break
            except Exception, e:
                print "clf.connect failed"

            global srv
            if only_one and srv and srv.success:
                raise SystemExit

    except KeyboardInterrupt:
        raise SystemExit
    finally:
        clf.close()

    raise SystemExit

if __name__ == '__main__':
    main()