diff options
Diffstat (limited to 'gr-digital/examples/ofdm/tunnel.py')
| -rwxr-xr-x | gr-digital/examples/ofdm/tunnel.py | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/gr-digital/examples/ofdm/tunnel.py b/gr-digital/examples/ofdm/tunnel.py new file mode 100755 index 000000000..74f2667fa --- /dev/null +++ b/gr-digital/examples/ofdm/tunnel.py @@ -0,0 +1,267 @@ +#!/usr/bin/env python +# +# Copyright 2005,2006,2011 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 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, 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 <linux/tun_if.h> + +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, callback, options): + gr.top_block.__init__(self) + + self.source = uhd_receiver(options.address, + options.bandwidth, + options.rx_freq, options.rx_gain, + options.antenna, options.verbose) + + self.sink = uhd_transmitter(options.address, + options.bandwidth, + options.tx_freq, options.tx_gain, + options.antenna, options.verbose) + + self.txpath = transmit_path(options) + self.rxpath = receive_path(callback, options) + + self.connect(self.txpath, self.sink) + self.connect(self.source, self.rxpath) + + 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.u_snk.set_freq(target_freq) + self.u_src.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_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]") + + digital.ofdm_mod.add_options(parser, expert_grp) + digital.ofdm_demod.add_options(parser, expert_grp) + transmit_path.add_options(parser, expert_grp) + receive_path.add_options(parser, expert_grp) + uhd_receiver.add_options(parser) + uhd_transmitter.add_options(parser) + + (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" + + # instantiate the MAC + mac = cs_mac(tun_fd, verbose=True) + + + # build the graph (PHY) + tb = my_top_block(mac.phy_rx_callback, options) + + mac.set_flow_graph(tb) # give the MAC a handle for the PHY + + print "modulation: %s" % (options.modulation,) + print "freq: %s" % (eng_notation.num_to_str(options.tx_freq)) + + 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 |