155 lines
4.3 KiB
C++
155 lines
4.3 KiB
C++
/* -*- c++ -*- */
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/* @file
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* @author Vadim Yanitskiy <axilirator@gmail.com>
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* @section LICENSE
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*
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* Gr-gsm is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* Gr-gsm is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with gr-gsm; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <gnuradio/io_signature.h>
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#include <boost/lexical_cast.hpp>
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#include "udp_socket.h"
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#include "trx_impl.h"
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namespace gr {
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namespace grgsm {
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trx::sptr
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trx::make(
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const std::string &remote_addr,
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const std::string &base_port)
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{
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int base_port_int = boost::lexical_cast<int> (base_port);
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return gnuradio::get_initial_sptr
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(new trx_impl(remote_addr, base_port_int));
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}
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/*
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* The private constructor
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*/
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trx_impl::trx_impl(const std::string &remote_addr, int base_port)
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: gr::block("trx",
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gr::io_signature::make(0, 0, 0),
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gr::io_signature::make(0, 0, 0))
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{
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message_port_register_in(pmt::mp("bursts"));
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set_msg_handler(pmt::mp("bursts"),
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boost::bind(&trx_impl::handle_dl_burst, this, _1));
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// Prepare port numbers
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std::string clck_src_port = boost::lexical_cast<std::string> (base_port + 0);
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std::string clck_dst_port = boost::lexical_cast<std::string> (base_port + 100);
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std::string data_src_port = boost::lexical_cast<std::string> (base_port + 2);
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std::string data_dst_port = boost::lexical_cast<std::string> (base_port + 102);
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// Init DATA interface
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d_data_sock = new udp_socket(remote_addr, data_src_port, data_dst_port);
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d_clck_sock = new udp_socket(remote_addr, clck_src_port, clck_dst_port);
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}
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/*
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* Our virtual destructor.
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*/
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trx_impl::~trx_impl()
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{
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// Release all UDP sockets and free memory
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delete d_data_sock;
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delete d_clck_sock;
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}
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/*
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* Create an UDP payload with clock indication
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*/
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void
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trx_impl::clck_ind_send(uint32_t frame_nr)
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{
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char buf[20];
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size_t n;
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n = snprintf(buf, 20, "IND CLOCK %u", frame_nr);
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d_clck_sock->udp_send((uint8_t *) buf, n + 1);
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}
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/*
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* Create an UDP payload with burst bits
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* and some channel data.
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*/
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void
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trx_impl::burst_pack(pmt::pmt_t msg, uint8_t *buf)
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{
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pmt::pmt_t header_plus_burst = pmt::cdr(msg);
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// Extract GSMTAP header from message
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gsmtap_hdr *header = (gsmtap_hdr *)
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pmt::blob_data(header_plus_burst);
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// Pack timeslot index
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buf[0] = header->timeslot;
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// Extract frame number
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uint32_t frame_nr = be32toh(header->frame_number);
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// HACK: send clock indications every 51-th frame
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if (frame_nr % 51 == 0)
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clck_ind_send(frame_nr);
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// Pack frame number
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buf[1] = (frame_nr >> 24) & 0xff;
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buf[2] = (frame_nr >> 16) & 0xff;
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buf[3] = (frame_nr >> 8) & 0xff;
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buf[4] = (frame_nr >> 0) & 0xff;
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// Pack RSSI (-dBm)
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buf[5] = -(uint8_t) header->signal_dbm;
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// Pack correlator timing offset (TOA)
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// FIXME: where to find this value?
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buf[6] = 0;
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buf[7] = 0;
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// Extract bits {0..1} from message
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// Despite GR-GSM uses int8_t, they are not real sbits {-127..127}
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uint8_t *burst = (uint8_t *)
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(pmt::blob_data(header_plus_burst)) + sizeof(gsmtap_hdr);
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// Convert to transceiver interface specific bits {255..0}
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for (int i = 0; i < 148; i++)
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buf[8 + i] = burst[i] ? 255 : 0;
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}
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void
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trx_impl::handle_dl_burst(pmt::pmt_t msg)
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{
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// 8 bytes of header + 148 bytes of burst
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uint8_t buf[156];
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// Compose a new UDP payload with burst
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burst_pack(msg, buf);
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// Send a burst
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d_data_sock->udp_send(buf, 156);
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}
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} /* namespace grgsm */
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} /* namespace gr */
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