Refactor the 'TRX Burst Interface' block

The following changes were made:

  - Both implementation and headers were merged with misc_utils
  - Fixed namespace mess: was gr::grgsm, became gr::gsm
  - More accurate class name was chosen: "trx_burst_if"

5 files changed, 526 insertions, 0 deletions

diff --git a/lib/misc_utils/CMakeLists.txt b/lib/misc_utils/CMakeLists.txt
index 81f2ca8..370f11c 100644
--- a/lib/misc_utils/CMakeLists.txt
+++ b/lib/misc_utils/CMakeLists.txt
@@ -34,5 +34,7 @@ add_sources(
     tmsi_dumper_impl.cc
     time_spec.cc
     fn_time.cc
+    udp_socket.cc
+    trx_burst_if_impl.cc
 )
 
diff --git a/lib/misc_utils/trx_burst_if_impl.cc b/lib/misc_utils/trx_burst_if_impl.cc
new file mode 100644
index 0000000..432ad2f
--- /dev/null
+++ b/lib/misc_utils/trx_burst_if_impl.cc
@@ -0,0 +1,275 @@
+/* -*- c++ -*- */
+/* @file
+ * @author Vadim Yanitskiy <axilirator@gmail.com>
+ * @section LICENSE
+ * 
+ * Gr-gsm 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.
+ * 
+ * Gr-gsm 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 gr-gsm; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ * 
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gnuradio/io_signature.h>
+#include <boost/lexical_cast.hpp>
+
+#include "udp_socket.h"
+#include "trx_burst_if_impl.h"
+
+#define BURST_SIZE     148
+#define DATA_IF_MTU    160
+
+/**
+ * 41-bit RACH synchronization sequence
+ * GSM 05.02 Chapter 5.2.7 Access burst (AB)
+ */
+static uint8_t rach_synch_seq[] = {
+  0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1,
+  1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0,
+  1, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0,
+};
+
+namespace gr {
+  namespace gsm {
+
+    trx_burst_if::sptr
+    trx_burst_if::make(
+      const std::string &remote_addr,
+      const std::string &base_port)
+    {
+      int base_port_int = boost::lexical_cast<int> (base_port);
+
+      return gnuradio::get_initial_sptr
+        (new trx_burst_if_impl(remote_addr, base_port_int));
+    }
+
+    /*
+     * The private constructor
+     */
+    trx_burst_if_impl::trx_burst_if_impl(
+      const std::string &remote_addr,
+      int base_port
+    ) : gr::block("trx_burst_if",
+        gr::io_signature::make(0, 0, 0),
+        gr::io_signature::make(0, 0, 0))
+    {
+        message_port_register_in(pmt::mp("bursts"));
+        message_port_register_out(pmt::mp("bursts"));
+
+        // Bind a port handler
+        set_msg_handler(pmt::mp("bursts"),
+          boost::bind(&trx_burst_if_impl::handle_dl_burst, this, _1));
+
+        // Prepare port numbers
+        std::string clck_src_port = boost::lexical_cast<std::string> (base_port + 0);
+        std::string clck_dst_port = boost::lexical_cast<std::string> (base_port + 100);
+        std::string data_src_port = boost::lexical_cast<std::string> (base_port + 2);
+        std::string data_dst_port = boost::lexical_cast<std::string> (base_port + 102);
+
+        // Init DATA & CLCK interfaces
+        d_data_sock = new udp_socket(remote_addr,
+          data_src_port, data_dst_port, DATA_IF_MTU);
+        d_clck_sock = new udp_socket(remote_addr,
+          clck_src_port, clck_dst_port, DATA_IF_MTU);
+
+        // Bind DATA interface handler
+        d_data_sock->udp_rx_handler = boost::bind(
+          &trx_burst_if_impl::handle_ul_burst, this, _1, _2);
+
+        // Init timeslot filter
+        d_ts_filter_tn = -1;
+    }
+
+    /*
+     * Our virtual destructor.
+     */
+    trx_burst_if_impl::~trx_burst_if_impl()
+    {
+        // Release all UDP sockets and free memory
+        delete d_data_sock;
+        delete d_clck_sock;
+    }
+
+    /*
+     * Timeslot filter API (getter and setter)
+     */
+    void
+    trx_burst_if_impl::ts_filter_set_tn(int tn)
+    {
+      d_ts_filter_tn = (tn >= 0 && tn <= 7) ? tn : -1;
+    }
+
+    int
+    trx_burst_if_impl::ts_filter_get_tn(void)
+    {
+      return d_ts_filter_tn;
+    }
+
+    /*
+     * Check if burst is a RACH burst
+     */
+    bool trx_burst_if_impl::detect_rach(uint8_t *burst)
+    {
+      // Compare synchronization sequence
+      for (int i = 0; i < 41; i++)
+        if (burst[i + 8] != rach_synch_seq[i])
+          return false;
+
+      // Make sure TB and GP are filled by 0x00
+      for (int i = 0; i < 63; i++)
+        if (burst[i + 85] != 0x00)
+          return false;
+
+      return true;
+    }
+
+    /*
+     * Create an UDP payload with clock indication
+     */
+    void
+    trx_burst_if_impl::clck_ind_send(uint32_t frame_nr)
+    {
+      char buf[20];
+      size_t n;
+
+      n = snprintf(buf, 20, "IND CLOCK %u", frame_nr);
+      d_clck_sock->udp_send((uint8_t *) buf, n + 1);
+    }
+
+    /*
+     * Create an UDP payload with burst bits
+     * and some channel data.
+     */
+    void
+    trx_burst_if_impl::burst_pack(pmt::pmt_t msg, uint8_t *buf)
+    {
+      pmt::pmt_t header_plus_burst = pmt::cdr(msg);
+
+      // Extract GSMTAP header from message
+      gsmtap_hdr *header = (gsmtap_hdr *)
+        pmt::blob_data(header_plus_burst);
+
+      // Pack timeslot index
+      buf[0] = header->timeslot;
+
+      // Extract frame number
+      uint32_t frame_nr = be32toh(header->frame_number);
+
+      // HACK: send clock indications every 51-th frame
+      if (frame_nr % 51 == 0)
+        clck_ind_send(frame_nr);
+
+      // Pack frame number
+      buf[1] = (frame_nr >> 24) & 0xff;
+      buf[2] = (frame_nr >> 16) & 0xff;
+      buf[3] = (frame_nr >>  8) & 0xff;
+      buf[4] = (frame_nr >>  0) & 0xff;
+
+      // Pack RSSI (-dBm)
+      buf[5] = -(uint8_t) header->signal_dbm;
+
+      // Pack correlator timing offset (TOA)
+      // FIXME: where to find this value?
+      buf[6] = 0;
+      buf[7] = 0;
+
+      // Extract bits {0..1} from message
+      // Despite GR-GSM uses int8_t, they are not real sbits {-127..127}
+      uint8_t *burst = (uint8_t *)
+        (pmt::blob_data(header_plus_burst)) + sizeof(gsmtap_hdr);
+
+      // Convert to transceiver interface specific bits {255..0}
+      for (int i = 0; i < 148; i++)
+        buf[8 + i] = burst[i] ? 255 : 0;
+
+      // Fill two unused bytes
+      buf[156] = 0x00;
+      buf[157] = 0x00;
+    }
+
+    void
+    trx_burst_if_impl::handle_dl_burst(pmt::pmt_t msg)
+    {
+      // 8 bytes of header + 148 bytes of burst
+      // + two unused, but required bytes
+      // otherwise bursts would be rejected
+      uint8_t buf[158];
+
+      // Compose a new UDP payload with burst
+      burst_pack(msg, buf);
+
+      // Timeslot filter
+      if (d_ts_filter_tn != -1 && buf[0] != d_ts_filter_tn)
+        return;
+
+      // Send a burst
+      d_data_sock->udp_send(buf, 158);
+    }
+
+    void
+    trx_burst_if_impl::handle_ul_burst(uint8_t *payload, size_t len)
+    {
+      // Check length according to the protocol
+      if (len != 154)
+        return;
+
+      /* Make sure TS index is correct */
+      if (payload[0] >= 8)
+        return;
+
+      /* Unpack and check frame number */
+      uint32_t fn = (payload[1] << 24)
+        | (payload[2] << 16)
+        | (payload[3] << 8)
+        | payload[4];
+
+      if (fn >= 2715648)
+        return;
+
+      // Prepare a buffer for GSMTAP header and burst
+      uint8_t buf[sizeof(gsmtap_hdr) + BURST_SIZE];
+
+      // Set up pointer to GSMTAP header structure
+      struct gsmtap_hdr *header = (struct gsmtap_hdr *) buf;
+      memset(header, 0x00, sizeof(struct gsmtap_hdr));
+
+      // Fill in basic info
+      header->version = GSMTAP_VERSION;
+      header->hdr_len = sizeof(gsmtap_hdr) / 4;
+      header->type = GSMTAP_TYPE_UM_BURST;
+
+      // Set timeslot index and frame number
+      header->timeslot = payload[0];
+      header->frame_number = htobe32(fn);
+
+      // Check if one is a RACH burst
+      header->sub_type = detect_rach(payload + 6) ?
+        GSMTAP_BURST_ACCESS : GSMTAP_BURST_NORMAL;
+
+      // Copy burst bits (0 & 1) for source message
+      memcpy(buf + sizeof(gsmtap_hdr), payload + 6, BURST_SIZE);
+
+      // Create a pmt blob
+      pmt::pmt_t blob = pmt::make_blob(buf, sizeof(gsmtap_hdr) + BURST_SIZE);
+      pmt::pmt_t msg = pmt::cons(pmt::PMT_NIL, blob);
+
+      /* Send a message to the output */
+      message_port_pub(pmt::mp("bursts"), msg);
+    }
+
+  } /* namespace gsm */
+} /* namespace gr */
diff --git a/lib/misc_utils/trx_burst_if_impl.h b/lib/misc_utils/trx_burst_if_impl.h
new file mode 100644
index 0000000..23d2264
--- /dev/null
+++ b/lib/misc_utils/trx_burst_if_impl.h
@@ -0,0 +1,61 @@
+/* -*- c++ -*- */
+/* @file
+ * @author Vadim Yanitskiy <axilirator@gmail.com>
+ * @section LICENSE
+ * 
+ * Gr-gsm 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.
+ * 
+ * Gr-gsm 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 gr-gsm; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ * 
+ */
+
+#ifndef INCLUDED_GRGSM_TRX_BURST_IF_IMPL_H
+#define INCLUDED_GRGSM_TRX_BURST_IF_IMPL_H
+
+#include <stddef.h>
+
+#include <grgsm/gsmtap.h>
+#include <grgsm/misc_utils/trx_burst_if.h>
+
+namespace gr {
+  namespace gsm {
+
+    class trx_burst_if_impl : public trx_burst_if
+    {
+     private:
+      udp_socket *d_data_sock;
+      udp_socket *d_clck_sock;
+      int d_ts_filter_tn;
+
+      bool detect_rach(uint8_t *burst);
+      void clck_ind_send(uint32_t frame_nr);
+      void burst_pack(pmt::pmt_t msg, uint8_t *buf);
+
+     public:
+      trx_burst_if_impl(const std::string &remote_addr, int base_port);
+      ~trx_burst_if_impl();
+
+      /* Timeslot filter API */
+      void ts_filter_set_tn(int tn);
+      int ts_filter_get_tn(void);
+
+      void handle_dl_burst(pmt::pmt_t msg);
+      void handle_ul_burst(uint8_t *payload, size_t len);
+    };
+
+  } // namespace gsm
+} // namespace gr
+
+#endif /* INCLUDED_GRGSM_TRX_BURST_IF_IMPL_H */
+
diff --git a/lib/misc_utils/udp_socket.cc b/lib/misc_utils/udp_socket.cc
new file mode 100644
index 0000000..5c689c7
--- /dev/null
+++ b/lib/misc_utils/udp_socket.cc
@@ -0,0 +1,119 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2013 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gnuradio/thread/thread.h>
+#include <gnuradio/io_signature.h>
+#include <gnuradio/blocks/pdu.h>
+#include <pmt/pmt.h>
+
+#include <boost/lexical_cast.hpp>
+#include "udp_socket.h"
+
+using boost::asio::ip::udp;
+
+namespace gr {
+  namespace gsm {
+
+    udp_socket::udp_socket(
+      const std::string &remote_addr,
+      const std::string &src_port,
+      const std::string &dst_port,
+      size_t mtu)
+    {
+      // Resize receive buffer according to MTU value
+      d_rxbuf.resize(mtu);
+
+      // Resolve remote host address
+      udp::resolver resolver(d_io_service);
+
+      udp::resolver::query rx_query(
+        udp::v4(), remote_addr, src_port,
+        boost::asio::ip::resolver_query_base::passive);
+      udp::resolver::query tx_query(
+        udp::v4(), remote_addr, dst_port,
+        boost::asio::ip::resolver_query_base::passive);
+
+      d_udp_endpoint_rx = *resolver.resolve(rx_query);
+      d_udp_endpoint_tx = *resolver.resolve(tx_query);
+
+      // Create a socket
+      d_udp_socket.reset(new udp::socket(d_io_service, d_udp_endpoint_rx));
+
+      // Setup read handler
+      d_udp_socket->async_receive_from(
+        boost::asio::buffer(d_rxbuf), d_udp_endpoint_rx,
+        boost::bind(&udp_socket::handle_udp_read, this,
+          boost::asio::placeholders::error,
+          boost::asio::placeholders::bytes_transferred));
+
+      // Start server
+      d_thread = gr::thread::thread(
+        boost::bind(&udp_socket::run_io_service, this));
+    }
+
+    udp_socket::~udp_socket()
+    {
+      // Stop server
+      d_io_service.stop();
+      d_thread.interrupt();
+      d_thread.join();
+    }
+
+    void
+    udp_socket::run_io_service(void)
+    {
+      d_io_service.run();
+    }
+
+    void
+    udp_socket::udp_send(uint8_t *data, size_t len)
+    {
+      d_udp_socket->send_to(
+        boost::asio::buffer(data, len),
+        d_udp_endpoint_tx);
+    }
+
+    void
+    udp_socket::handle_udp_read(
+      const boost::system::error_code& error,
+      size_t bytes_transferred)
+    {
+      if (error)
+        return;
+
+      // Call incoming data handler
+      if (udp_rx_handler != NULL)
+        udp_rx_handler((uint8_t *) &d_rxbuf[0], bytes_transferred);
+
+      d_udp_socket->async_receive_from(
+        boost::asio::buffer(d_rxbuf), d_udp_endpoint_rx,
+        boost::bind(&udp_socket::handle_udp_read, this,
+          boost::asio::placeholders::error,
+          boost::asio::placeholders::bytes_transferred));
+    }
+
+  } /* namespace gsm */
+}/* namespace gr */
diff --git a/lib/misc_utils/udp_socket.h b/lib/misc_utils/udp_socket.h
new file mode 100644
index 0000000..15b2c66
--- /dev/null
+++ b/lib/misc_utils/udp_socket.h
@@ -0,0 +1,69 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2013 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.
+ */
+
+#ifndef INCLUDED_GRGSM_TRX_UDP_SOCKET_H
+#define INCLUDED_GRGSM_TRX_UDP_SOCKET_H
+
+#include <gnuradio/thread/thread.h>
+
+#include <boost/function.hpp>
+#include <boost/array.hpp>
+#include <boost/asio.hpp>
+#include <boost/bind.hpp>
+#include <pmt/pmt.h>
+
+namespace gr {
+  namespace gsm {
+
+    class udp_socket
+    {
+    private:
+      boost::asio::io_service d_io_service;
+      std::vector<char> d_rxbuf;
+      gr::thread::thread d_thread;
+      bool d_started;
+      bool d_finished;
+
+      boost::asio::ip::udp::endpoint d_udp_endpoint_rx;
+      boost::asio::ip::udp::endpoint d_udp_endpoint_tx;
+      boost::shared_ptr<boost::asio::ip::udp::socket> d_udp_socket;
+
+      void handle_udp_read(const boost::system::error_code& error,
+        size_t bytes_transferred);
+      void run_io_service(void);
+
+    public:
+      udp_socket(
+        const std::string &remote_addr,
+        const std::string &src_port,
+        const std::string &dst_port,
+        size_t mtu);
+      ~udp_socket();
+
+      void udp_send(uint8_t *data, size_t len);
+      boost::function<void (uint8_t *, size_t)> udp_rx_handler;
+    };
+
+  } /* namespace gsm */
+} /* namespace gr */
+
+#endif /* INCLUDED_GRGSM_TRX_UDP_SOCKET_H */