uhd: add new transport interface and base class implementation

New interface aimed to replace zero_copy_if for new code, including new
RFNoC development and redesign of streamer objects.

Generic implementation of send and receive transport interfaces to allow
reuse by various transport types. Derived classes implement
transport-specific functions that are invoked by the base classes
through CRTP.

2 files changed, 70 insertions, 0 deletions

diff --git a/host/include/uhd/transport/CMakeLists.txt b/host/include/uhd/transport/CMakeLists.txt
index d0810e502..400b3db0b 100644
--- a/host/include/uhd/transport/CMakeLists.txt
+++ b/host/include/uhd/transport/CMakeLists.txt
@@ -10,6 +10,7 @@ UHD_INSTALL(FILES
     bounded_buffer.ipp
     buffer_pool.hpp
     chdr.hpp
+    frame_buff.hpp
     if_addrs.hpp
     udp_constants.hpp
     udp_simple.hpp
diff --git a/host/include/uhd/transport/frame_buff.hpp b/host/include/uhd/transport/frame_buff.hpp
new file mode 100644
index 000000000..c335f0c4b
--- /dev/null
+++ b/host/include/uhd/transport/frame_buff.hpp
@@ -0,0 +1,69 @@
+//
+// Copyright 2019 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#ifndef INCLUDED_UHD_TRANSPORT_FRAME_BUFF_HPP
+#define INCLUDED_UHD_TRANSPORT_FRAME_BUFF_HPP
+
+#include <memory>
+
+namespace uhd { namespace transport {
+
+/*!
+ * Contains a reference to a frame buffer managed by a link.
+ */
+class frame_buff
+{
+public:
+    /*!
+     * No-op deleter to prevent unique_ptr from deleting the buffer if the
+     * pointer goes out of scope. The lifetime of the buffers is controlled
+     * by the links.
+     */
+    struct deleter
+    {
+        void operator()(frame_buff*) {}
+    };
+
+    using uptr = std::unique_ptr<frame_buff, deleter>;
+
+    /*!
+     * Get the raw data buffer contained within the frame buffer
+     * \return a pointer to the buffer memory.
+     */
+    void* data() const
+    {
+        return _data;
+    }
+
+    /*!
+     * Returns the size of the packet
+     * \return the size of the packet contained in the frame buffer, in bytes.
+     */
+    size_t packet_size() const
+    {
+        return _packet_size;
+    }
+
+    /*!
+     * Sets the size of the packet contained in the frame buffer, in bytes.
+     * \param size Number of bytes occupied in the buffer
+     */
+    void set_packet_size(size_t size)
+    {
+        _packet_size = size;
+    }
+
+protected:
+    /*! Pointer to data of current frame */
+    void* _data = nullptr;
+
+    /*! Size of packet in current frame */
+    size_t _packet_size = 0;
+};
+
+}} // namespace uhd::transport
+
+#endif /* INCLUDED_UHD_TRANSPORT_FRAME_BUFF_HPP */