rfspace: Send periodic keep-alive packets.

This patch enables sending keep-alive packets at 1 minute interval to
RFSpace networked radios. Without this the TCP connection to the radio
is closed after about 5 minutes (by the OS?).

2 files changed, 37 insertions, 0 deletions

diff --git a/lib/rfspace/rfspace_source_c.cc b/lib/rfspace/rfspace_source_c.cc
index f9c587d..74708c6 100644
--- a/lib/rfspace/rfspace_source_c.cc
+++ b/lib/rfspace/rfspace_source_c.cc
@@ -475,6 +475,16 @@ rfspace_source_c::rfspace_source_c (const std::string &args)
     set_sample_rate( 240000 );
     set_bandwidth( 0 );
   }
+
+  /* start TCP keepalive thread */
+  if ( RFSPACE_NETSDR == _radio ||
+       RFSPACE_SDR_IP == _radio ||
+       RFSPACE_CLOUDIQ == _radio )
+  {
+    _run_tcp_keepalive_task = true;
+    _thread = gr::thread::thread( boost::bind(&rfspace_source_c::tcp_keepalive_task, this) );
+  }
+
 #if 0
   std::cerr << "sample_rates: " << get_sample_rates().to_pp_string() << std::endl;
   std::cerr << "sample rate: " << (uint32_t)get_sample_rate() << std::endl;
@@ -505,6 +515,12 @@ rfspace_source_c::~rfspace_source_c ()
 
     _thread.join();
   }
+  else
+  {
+    _run_tcp_keepalive_task = false;
+    _thread.interrupt();
+    _thread.join();
+  }
 
   close(_usb);
 
@@ -580,6 +596,8 @@ bool rfspace_source_c::transaction( const unsigned char *cmd, size_t size,
   }
   else
   {
+    boost::mutex::scoped_lock lock(_tcp_lock);
+
 #ifdef USE_ASIO
     _t.write_some( boost::asio::buffer(cmd, size) );
 
@@ -730,6 +748,22 @@ void rfspace_source_c::usb_read_task()
   }
 }
 
+/* send periodic status requests to keep TCP connection alive */
+void rfspace_source_c::tcp_keepalive_task()
+{
+  std::vector< unsigned char > response;
+  unsigned char status_pkt[] = { 0x04, 0x20, 0x05, 0x00 };
+
+  if ( -1 == _tcp )
+    return;
+
+  while ( _run_tcp_keepalive_task )
+  {
+    boost::this_thread::sleep_for(boost::chrono::seconds(60));
+    transaction( status_pkt, sizeof(status_pkt), response );
+  }
+}
+
 bool rfspace_source_c::start()
 {
   _sequence = 0;
diff --git a/lib/rfspace/rfspace_source_c.h b/lib/rfspace/rfspace_source_c.h
index 7d89ddc..c656063 100644
--- a/lib/rfspace/rfspace_source_c.h
+++ b/lib/rfspace/rfspace_source_c.h
@@ -129,6 +129,7 @@ private: /* functions */
                     std::vector< unsigned char > &response );
 
   void usb_read_task();
+  void tcp_keepalive_task();
 
 private: /* members */
   enum radio_type
@@ -162,6 +163,8 @@ private: /* members */
 
   gr::thread::thread _thread;
   bool _run_usb_read_task;
+  bool _run_tcp_keepalive_task;
+  boost::mutex _tcp_lock;
 
   boost::circular_buffer<gr_complex> *_fifo;
   boost::mutex _fifo_lock;