simplification of udp asio socket stuff

2 files changed, 43 insertions, 44 deletions

diff --git a/host/include/uhd/transport/zero_copy.hpp b/host/include/uhd/transport/zero_copy.hpp
index 4fc1df9de..fdc5b141c 100644
--- a/host/include/uhd/transport/zero_copy.hpp
+++ b/host/include/uhd/transport/zero_copy.hpp
@@ -45,7 +45,7 @@ public:
      * Get the size of the underlying buffer.
      * \return the number of bytes
      */
-    size_t size(void){
+    size_t size(void) const{
         return boost::asio::buffer_size(this->get());
     }
 
@@ -53,7 +53,7 @@ public:
      * Get a pointer to the underlying buffer.
      * \return a pointer into memory
      */
-    template <class T> T cast(void){
+    template <class T> T cast(void) const{
         return boost::asio::buffer_cast<T>(this->get());
     }
 
@@ -63,7 +63,7 @@ private:
      * The buffer has a reference to memory and a size.
      * \return a boost asio const buffer
      */
-    virtual const boost::asio::const_buffer &get(void) = 0;
+    virtual const boost::asio::const_buffer &get(void) const = 0;
 };
 
 /*!
@@ -87,7 +87,7 @@ public:
      * Get the size of the underlying buffer.
      * \return the number of bytes
      */
-    size_t size(void){
+    size_t size(void) const{
         return boost::asio::buffer_size(this->get());
     }
 
@@ -95,7 +95,7 @@ public:
      * Get a pointer to the underlying buffer.
      * \return a pointer into memory
      */
-    template <class T> T cast(void){
+    template <class T> T cast(void) const{
         return boost::asio::buffer_cast<T>(this->get());
     }
 
@@ -105,7 +105,7 @@ private:
      * The buffer has a reference to memory and a size.
      * \return a boost asio mutable buffer
      */
-    virtual const boost::asio::mutable_buffer &get(void) = 0;
+    virtual const boost::asio::mutable_buffer &get(void) const = 0;
 };
 
 /*!
diff --git a/host/lib/transport/udp_zero_copy_asio.cpp b/host/lib/transport/udp_zero_copy_asio.cpp
index ee44803f4..c26b39867 100644
--- a/host/lib/transport/udp_zero_copy_asio.cpp
+++ b/host/lib/transport/udp_zero_copy_asio.cpp
@@ -16,9 +16,9 @@
 //
 
 #include <uhd/transport/udp_zero_copy.hpp>
+#include <uhd/utils/assert.hpp>
 #include <boost/cstdint.hpp>
 #include <boost/asio.hpp>
-#include <boost/thread.hpp>
 #include <boost/format.hpp>
 #include <iostream>
 
@@ -26,65 +26,56 @@ using namespace uhd::transport;
 
 /***********************************************************************
  * Managed receive buffer implementation for udp zero-copy asio:
- *   Frees the memory held by the const buffer on done.
  **********************************************************************/
 class managed_recv_buffer_impl : public managed_recv_buffer{
 public:
     managed_recv_buffer_impl(const boost::asio::const_buffer &buff) : _buff(buff){
-        _done = false;
+        /* NOP */
     }
 
     ~managed_recv_buffer_impl(void){
-        if (not _done) this->done();
+        /* NOP */
     }
 
     void done(void){
-        _done = true;
-        delete [] boost::asio::buffer_cast<const boost::uint32_t *>(_buff);
+        /* NOP */
     }
 
 private:
-    const boost::asio::const_buffer &get(void){
+    const boost::asio::const_buffer &get(void) const{
         return _buff;
     }
 
     const boost::asio::const_buffer _buff;
-    bool _done;
 };
 
 /***********************************************************************
  * Managed send buffer implementation for udp zero-copy asio:
- *   Sends and frees the memory held by the mutable buffer on done.
  **********************************************************************/
 class managed_send_buffer_impl : public managed_send_buffer{
 public:
     managed_send_buffer_impl(
         const boost::asio::mutable_buffer &buff,
         boost::asio::ip::udp::socket *socket
-    ) : _buff(buff){
-        _done = false;
-        _socket = socket;
+    ) : _buff(buff), _socket(socket){
+        /* NOP */
     }
 
     ~managed_send_buffer_impl(void){
-        if (not _done) this->done(0);
+        /* NOP */
     }
 
     void done(size_t num_bytes){
-        _done = true;
-        boost::uint32_t *mem = boost::asio::buffer_cast<boost::uint32_t *>(_buff);
-        _socket->send(boost::asio::buffer(mem, num_bytes));
-        delete [] mem;
+        _socket->send(boost::asio::buffer(_buff, num_bytes));
     }
 
 private:
-    const boost::asio::mutable_buffer &get(void){
+    const boost::asio::mutable_buffer &get(void) const{
         return _buff;
     }
 
     const boost::asio::mutable_buffer _buff;
     boost::asio::ip::udp::socket      *_socket;
-    bool _done;
 };
 
 /***********************************************************************
@@ -94,6 +85,8 @@ private:
  *   However, it is not a true zero copy implementation as each
  *   send and recv requires a copy operation to/from userspace.
  **********************************************************************/
+static const size_t max_buff_size = 2000; //assume max size on send and recv
+
 class udp_zero_copy_impl : public udp_zero_copy{
 public:
     //structors
@@ -121,6 +114,11 @@ public:
 private:
     boost::asio::ip::udp::socket   *_socket;
     boost::asio::io_service        _io_service;
+
+    //send and recv buffer memory (allocated once)
+    boost::uint8_t _send_mem[max_buff_size], _recv_mem[max_buff_size];
+
+    managed_send_buffer::sptr _send_buff;
 };
 
 udp_zero_copy_impl::udp_zero_copy_impl(const std::string &addr, const std::string &port){
@@ -131,10 +129,25 @@ udp_zero_copy_impl::udp_zero_copy_impl(const std::string &addr, const std::strin
     boost::asio::ip::udp::resolver::query query(boost::asio::ip::udp::v4(), addr, port);
     boost::asio::ip::udp::endpoint receiver_endpoint = *resolver.resolve(query);
 
-    // Create, open, and connect the socket
+    // create, open, and connect the socket
     _socket = new boost::asio::ip::udp::socket(_io_service);
     _socket->open(boost::asio::ip::udp::v4());
     _socket->connect(receiver_endpoint);
+
+    // create the managed send buff (just once)
+    _send_buff = managed_send_buffer::sptr(new managed_send_buffer_impl(
+        boost::asio::buffer(_send_mem, max_buff_size), _socket
+    ));
+
+    // set recv timeout
+    timeval tv;
+    tv.tv_sec = 0;
+    tv.tv_usec = 100*1000; //100 ms
+    UHD_ASSERT_THROW(setsockopt(
+        _socket->native(),
+        SOL_SOCKET, SO_RCVTIMEO,
+        (timeval *)&tv, sizeof(timeval)
+    ) == 0);
 }
 
 udp_zero_copy_impl::~udp_zero_copy_impl(void){
@@ -142,31 +155,17 @@ udp_zero_copy_impl::~udp_zero_copy_impl(void){
 }
 
 managed_recv_buffer::sptr udp_zero_copy_impl::get_recv_buff(void){
-    //implement timeout through polling and sleeping
-    size_t available = 0;
-    boost::asio::deadline_timer timer(_socket->get_io_service());
-    timer.expires_from_now(boost::posix_time::milliseconds(100));
-    while (not ((available = _socket->available()) or timer.expires_from_now().is_negative())){
-        boost::this_thread::sleep(boost::posix_time::milliseconds(1));
-    }
-
-    //receive only if data is available
-    boost::uint32_t *buff_mem = new boost::uint32_t[available/sizeof(boost::uint32_t)];
-    if (available){
-        available = _socket->receive(boost::asio::buffer(buff_mem, available));
-    }
+    //call recv() with timeout option
+    size_t num_bytes = _socket->receive(boost::asio::buffer(_recv_mem, max_buff_size));
 
     //create a new managed buffer to house the data
     return managed_recv_buffer::sptr(
-        new managed_recv_buffer_impl(boost::asio::buffer(buff_mem, available))
+        new managed_recv_buffer_impl(boost::asio::buffer(_recv_mem, num_bytes))
     );
 }
 
 managed_send_buffer::sptr udp_zero_copy_impl::get_send_buff(void){
-    boost::uint32_t *buff_mem = new boost::uint32_t[2000/sizeof(boost::uint32_t)];
-    return managed_send_buffer::sptr(
-        new managed_send_buffer_impl(boost::asio::buffer(buff_mem, 2000), _socket)
-    );
+    return _send_buff;
 }
 
 /***********************************************************************