#!/usr/bin/env python # # Copyright 2005,2006,2009,2011 Free Software Foundation, Inc. # # This file is part of GNU Radio # # GNU Radio is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 3, or (at your option) # any later version. # # GNU Radio is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with GNU Radio; see the file COPYING. If not, write to # the Free Software Foundation, Inc., 51 Franklin Street, # Boston, MA 02110-1301, USA. # # //////////////////////////////////////////////////////////////////// # # This code sets up up a virtual ethernet interface (typically # gr0), and relays packets between the interface and the GNU Radio # PHY+MAC # # What this means in plain language, is that if you've got a couple # of USRPs on different machines, and if you run this code on those # machines, you can talk between them using normal TCP/IP # networking. # # //////////////////////////////////////////////////////////////////// from gnuradio import gr, digital from gnuradio import eng_notation from gnuradio.eng_option import eng_option from optparse import OptionParser # from current dir from receive_path import receive_path from transmit_path import transmit_path from uhd_interface import uhd_transmitter from uhd_interface import uhd_receiver import os, sys import random, time, struct #print os.getpid() #raw_input('Attach and press enter') # //////////////////////////////////////////////////////////////////// # # Use the Universal TUN/TAP device driver to move packets to/from # kernel # # See /usr/src/linux/Documentation/networking/tuntap.txt # # //////////////////////////////////////////////////////////////////// # Linux specific... # TUNSETIFF ifr flags from IFF_TUN = 0x0001 # tunnel IP packets IFF_TAP = 0x0002 # tunnel ethernet frames IFF_NO_PI = 0x1000 # don't pass extra packet info IFF_ONE_QUEUE = 0x2000 # beats me ;) def open_tun_interface(tun_device_filename): from fcntl import ioctl mode = IFF_TAP | IFF_NO_PI TUNSETIFF = 0x400454ca tun = os.open(tun_device_filename, os.O_RDWR) ifs = ioctl(tun, TUNSETIFF, struct.pack("16sH", "gr%d", mode)) ifname = ifs[:16].strip("\x00") return (tun, ifname) # //////////////////////////////////////////////////////////////////// # the flow graph # //////////////////////////////////////////////////////////////////// class my_top_block(gr.top_block): def __init__(self, mod_class, demod_class, rx_callback, options): gr.top_block.__init__(self) # Get the modulation's bits_per_symbol args = mod_class.extract_kwargs_from_options(options) symbol_rate = options.bitrate / mod_class(**args).bits_per_symbol() self.source = uhd_receiver(options.args, symbol_rate, options.samples_per_symbol, options.rx_freq, options.rx_gain, options.spec, options.antenna, options.verbose) self.sink = uhd_transmitter(options.args, symbol_rate, options.samples_per_symbol, options.tx_freq, options.tx_gain, options.spec, options.antenna, options.verbose) options.samples_per_symbol = self.source._sps self.txpath = transmit_path(mod_class, options) self.rxpath = receive_path(demod_class, rx_callback, options) self.connect(self.txpath, self.sink) self.connect(self.source, self.rxpath) def send_pkt(self, payload='', eof=False): return self.txpath.send_pkt(payload, eof) def carrier_sensed(self): """ Return True if the receive path thinks there's carrier """ return self.rxpath.carrier_sensed() def set_freq(self, target_freq): """ Set the center frequency we're interested in. """ self.sink.set_freq(target_freq) self.source.set_freq(target_freq) # //////////////////////////////////////////////////////////////////// # Carrier Sense MAC # //////////////////////////////////////////////////////////////////// class cs_mac(object): """ Prototype carrier sense MAC Reads packets from the TUN/TAP interface, and sends them to the PHY. Receives packets from the PHY via phy_rx_callback, and sends them into the TUN/TAP interface. Of course, we're not restricted to getting packets via TUN/TAP, this is just an example. """ def __init__(self, tun_fd, verbose=False): self.tun_fd = tun_fd # file descriptor for TUN/TAP interface self.verbose = verbose self.tb = None # top block (access to PHY) def set_top_block(self, tb): self.tb = tb def phy_rx_callback(self, ok, payload): """ Invoked by thread associated with PHY to pass received packet up. @param ok: bool indicating whether payload CRC was OK @param payload: contents of the packet (string) """ if self.verbose: print "Rx: ok = %r len(payload) = %4d" % (ok, len(payload)) if ok: os.write(self.tun_fd, payload) def main_loop(self): """ Main loop for MAC. Only returns if we get an error reading from TUN. FIXME: may want to check for EINTR and EAGAIN and reissue read """ min_delay = 0.001 # seconds while 1: payload = os.read(self.tun_fd, 10*1024) if not payload: self.tb.send_pkt(eof=True) break if self.verbose: print "Tx: len(payload) = %4d" % (len(payload),) delay = min_delay while self.tb.carrier_sensed(): sys.stderr.write('B') time.sleep(delay) if delay < 0.050: delay = delay * 2 # exponential back-off self.tb.send_pkt(payload) # ///////////////////////////////////////////////////////////////////////////// # main # ///////////////////////////////////////////////////////////////////////////// def main(): mods = digital.modulation_utils.type_1_mods() demods = digital.modulation_utils.type_1_demods() parser = OptionParser (option_class=eng_option, conflict_handler="resolve") expert_grp = parser.add_option_group("Expert") parser.add_option("-m", "--modulation", type="choice", choices=mods.keys(), default='gmsk', help="Select modulation from: %s [default=%%default]" % (', '.join(mods.keys()),)) parser.add_option("-s", "--size", type="eng_float", default=1500, help="set packet size [default=%default]") parser.add_option("-v","--verbose", action="store_true", default=False) expert_grp.add_option("-c", "--carrier-threshold", type="eng_float", default=30, help="set carrier detect threshold (dB) [default=%default]") expert_grp.add_option("","--tun-device-filename", default="/dev/net/tun", help="path to tun device file [default=%default]") transmit_path.add_options(parser, expert_grp) receive_path.add_options(parser, expert_grp) uhd_receiver.add_options(parser) uhd_transmitter.add_options(parser) for mod in mods.values(): mod.add_options(expert_grp) for demod in demods.values(): demod.add_options(expert_grp) (options, args) = parser.parse_args () if len(args) != 0: parser.print_help(sys.stderr) sys.exit(1) # open the TUN/TAP interface (tun_fd, tun_ifname) = open_tun_interface(options.tun_device_filename) # Attempt to enable realtime scheduling r = gr.enable_realtime_scheduling() if r == gr.RT_OK: realtime = True else: realtime = False print "Note: failed to enable realtime scheduling" # instantiate the MAC mac = cs_mac(tun_fd, verbose=True) # build the graph (PHY) tb = my_top_block(mods[options.modulation], demods[options.modulation], mac.phy_rx_callback, options) mac.set_top_block(tb) # give the MAC a handle for the PHY if tb.txpath.bitrate() != tb.rxpath.bitrate(): print "WARNING: Transmit bitrate = %sb/sec, Receive bitrate = %sb/sec" % ( eng_notation.num_to_str(tb.txpath.bitrate()), eng_notation.num_to_str(tb.rxpath.bitrate())) print "modulation: %s" % (options.modulation,) print "freq: %s" % (eng_notation.num_to_str(options.tx_freq)) print "bitrate: %sb/sec" % (eng_notation.num_to_str(tb.txpath.bitrate()),) print "samples/symbol: %3d" % (tb.txpath.samples_per_symbol(),) tb.rxpath.set_carrier_threshold(options.carrier_threshold) print "Carrier sense threshold:", options.carrier_threshold, "dB" print print "Allocated virtual ethernet interface: %s" % (tun_ifname,) print "You must now use ifconfig to set its IP address. E.g.," print print " $ sudo ifconfig %s 192.168.200.1" % (tun_ifname,) print print "Be sure to use a different address in the same subnet for each machine." print tb.start() # Start executing the flow graph (runs in separate threads) mac.main_loop() # don't expect this to return... tb.stop() # but if it does, tell flow graph to stop. tb.wait() # wait for it to finish if __name__ == '__main__': try: main() except KeyboardInterrupt: pass