#!/usr/bin/env python # # Copyright 2005,2006 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 2, 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, gru, blks2 from gnuradio import usrp from gnuradio import eng_notation from gnuradio.eng_option import eng_option from optparse import OptionParser import random import time import struct import sys import os # from current dir from transmit_path import transmit_path from receive_path import receive_path import fusb_options #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 usrp_graph(gr.top_block): def __init__(self, callback, options): gr.top_block.__init__(self) self._tx_freq = options.tx_freq # tranmitter's center frequency self._tx_subdev_spec = options.tx_subdev_spec # daughterboard to use self._interp = options.interp # interpolating rate for the USRP (prelim) self._rx_freq = options.rx_freq # receiver's center frequency self._rx_gain = options.rx_gain # receiver's gain self._rx_subdev_spec = options.rx_subdev_spec # daughterboard to use self._decim = options.decim # Decimating rate for the USRP (prelim) self._fusb_block_size = options.fusb_block_size # usb info for USRP self._fusb_nblocks = options.fusb_nblocks # usb info for USRP if self._tx_freq is None: sys.stderr.write("-f FREQ or --freq FREQ or --tx-freq FREQ must be specified\n") raise SystemExit if self._rx_freq is None: sys.stderr.write("-f FREQ or --freq FREQ or --rx-freq FREQ must be specified\n") raise SystemExit # Set up USRP sink and source self._setup_usrp_sink() self._setup_usrp_source() # Set center frequency of USRP ok = self.set_freq(self._tx_freq) if not ok: print "Failed to set Tx frequency to %s" % (eng_notation.num_to_str(self._tx_freq),) raise ValueError # copy the final answers back into options for use by modulator #options.bitrate = self._bitrate self.txpath = transmit_path(options) self.rxpath = receive_path(callback, options) self.connect(self.txpath, self.u_snk) self.connect(self.u_src, self.rxpath) def carrier_sensed(self): """ Return True if the receive path thinks there's carrier """ return self.rxpath.carrier_sensed() def _setup_usrp_sink(self): """ Creates a USRP sink, determines the settings for best bitrate, and attaches to the transmitter's subdevice. """ self.u_snk = usrp.sink_c(fusb_block_size=self._fusb_block_size, fusb_nblocks=self._fusb_nblocks) self.u_snk.set_interp_rate(self._interp) # determine the daughterboard subdevice we're using if self._tx_subdev_spec is None: self._tx_subdev_spec = usrp.pick_tx_subdevice(self.u_snk) self.u_snk.set_mux(usrp.determine_tx_mux_value(self.u_snk, self._tx_subdev_spec)) self.subdev = usrp.selected_subdev(self.u_snk, self._tx_subdev_spec) # Set the USRP for maximum transmit gain # (Note that on the RFX cards this is a nop.) self.set_gain(self.subdev.gain_range()[1]) # enable Auto Transmit/Receive switching self.set_auto_tr(True) def _setup_usrp_source(self): self.u_src = usrp.source_c (fusb_block_size=self._fusb_block_size, fusb_nblocks=self._fusb_nblocks) adc_rate = self.u_src.adc_rate() self.u_src.set_decim_rate(self._decim) # determine the daughterboard subdevice we're using if self._rx_subdev_spec is None: self._rx_subdev_spec = usrp.pick_rx_subdevice(self.u_src) self.subdev = usrp.selected_subdev(self.u_src, self._rx_subdev_spec) self.u_src.set_mux(usrp.determine_rx_mux_value(self.u_src, self._rx_subdev_spec)) def set_freq(self, target_freq): """ Set the center frequency we're interested in. @param target_freq: frequency in Hz @rypte: bool Tuning is a two step process. First we ask the front-end to tune as close to the desired frequency as it can. Then we use the result of that operation and our target_frequency to determine the value for the digital up converter. """ r_snk = self.u_snk.tune(self.subdev.which(), self.subdev, target_freq) r_src = self.u_src.tune(self.subdev.which(), self.subdev, target_freq) if r_snk and r_src: return True return False def set_gain(self, gain): """ Sets the analog gain in the USRP """ self.gain = gain self.subdev.set_gain(gain) def set_auto_tr(self, enable): """ Turns on auto transmit/receive of USRP daughterboard (if exits; else ignored) """ return self.subdev.set_auto_tr(enable) def interp(self): return self._interp def add_options(normal, expert): """ Adds usrp-specific options to the Options Parser """ add_freq_option(normal) normal.add_option("-T", "--tx-subdev-spec", type="subdev", default=None, help="select USRP Tx side A or B") normal.add_option("-v", "--verbose", action="store_true", default=False) expert.add_option("", "--tx-freq", type="eng_float", default=None, help="set transmit frequency to FREQ [default=%default]", metavar="FREQ") expert.add_option("-i", "--interp", type="intx", default=256, help="set fpga interpolation rate to INTERP [default=%default]") normal.add_option("-R", "--rx-subdev-spec", type="subdev", default=None, help="select USRP Rx side A or B") normal.add_option("", "--rx-gain", type="eng_float", default=None, metavar="GAIN", help="set receiver gain in dB [default=midpoint]. See also --show-rx-gain-range") normal.add_option("", "--show-rx-gain-range", action="store_true", default=False, help="print min and max Rx gain available on selected daughterboard") normal.add_option("-v", "--verbose", action="store_true", default=False) expert.add_option("", "--rx-freq", type="eng_float", default=None, help="set Rx frequency to FREQ [default=%default]", metavar="FREQ") expert.add_option("-d", "--decim", type="intx", default=128, help="set fpga decimation rate to DECIM [default=%default]") expert.add_option("", "--snr", type="eng_float", default=30, help="set the SNR of the channel in dB [default=%default]") # Make a static method to call before instantiation add_options = staticmethod(add_options) def _print_verbage(self): """ Prints information about the transmit path """ print "Using TX d'board %s" % (self.subdev.side_and_name(),) print "modulation: %s" % (self._modulator_class.__name__) print "interp: %3d" % (self._interp) print "Tx Frequency: %s" % (eng_notation.num_to_str(self._tx_freq)) def add_freq_option(parser): """ Hackery that has the -f / --freq option set both tx_freq and rx_freq """ def freq_callback(option, opt_str, value, parser): parser.values.rx_freq = value parser.values.tx_freq = value if not parser.has_option('--freq'): parser.add_option('-f', '--freq', type="eng_float", action="callback", callback=freq_callback, help="set Tx and/or Rx frequency to FREQ [default=%default]", metavar="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_flow_graph(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.txpath.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.txpath.send_pkt(payload) # ///////////////////////////////////////////////////////////////////////////// # main # ///////////////////////////////////////////////////////////////////////////// def main(): parser = OptionParser (option_class=eng_option, conflict_handler="resolve") expert_grp = parser.add_option_group("Expert") parser.add_option("-m", "--modulation", type="choice", choices=['bpsk', 'qpsk'], default='bpsk', help="Select modulation from: bpsk, qpsk [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]") usrp_graph.add_options(parser, expert_grp) transmit_path.add_options(parser, expert_grp) receive_path.add_options(parser, expert_grp) blks2.ofdm_mod.add_options(parser, expert_grp) blks2.ofdm_demod.add_options(parser, expert_grp) fusb_options.add_options(expert_grp) (options, args) = parser.parse_args () if len(args) != 0: parser.print_help(sys.stderr) sys.exit(1) if options.rx_freq is None or options.tx_freq is None: sys.stderr.write("You must specify -f FREQ or --freq FREQ\n") 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" # If the user hasn't set the fusb_* parameters on the command line, # pick some values that will reduce latency. if options.fusb_block_size == 0 and options.fusb_nblocks == 0: if realtime: # be more aggressive options.fusb_block_size = gr.prefs().get_long('fusb', 'rt_block_size', 1024) options.fusb_nblocks = gr.prefs().get_long('fusb', 'rt_nblocks', 16) else: options.fusb_block_size = gr.prefs().get_long('fusb', 'block_size', 4096) options.fusb_nblocks = gr.prefs().get_long('fusb', 'nblocks', 16) #print "fusb_block_size =", options.fusb_block_size #print "fusb_nblocks =", options.fusb_nblocks # instantiate the MAC mac = cs_mac(tun_fd, verbose=True) # build the graph (PHY) tb = usrp_graph(mac.phy_rx_callback, options) mac.set_flow_graph(tb) # give the MAC a handle for the PHY #if fg.txpath.bitrate() != fg.rxpath.bitrate(): # print "WARNING: Transmit bitrate = %sb/sec, Receive bitrate = %sb/sec" % ( # eng_notation.num_to_str(fg.txpath.bitrate()), # eng_notation.num_to_str(fg.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(fg.txpath.bitrate()),) #print "samples/symbol: %3d" % (fg.txpath.samples_per_symbol(),) #print "interp: %3d" % (fg.txpath.interp(),) #print "decim: %3d" % (fg.rxpath.decim(),) 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