mpmd: Refactor MPM transport architecture, use managers

This splits up the transport code in mpmd_impl across multiple classes
to properly leverage the request_xport/commit_xport API in MPM.
Different types of transport (UDP, liberio) use their own distinct
classes, which are generated dynamically on request.

This is a true refactoring despite the large amount of changes; there
are no functional differences.

Reviewed-By: Brent Stapleton <brent.stapleton@ettus.com>
Reviewed-By: Trung Tran <trung.tran@ettus.com>
Reviewed-By: Ashish Chaudhari <ashish.chaudhari@ettus.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/host/lib/usrp/mpmd/mpmd_xport_mgr.hpp b/host/lib/usrp/mpmd/mpmd_xport_mgr.hpp
new file mode 100644
index 000000000..2da4af323
--- /dev/null
+++ b/host/lib/usrp/mpmd/mpmd_xport_mgr.hpp
@@ -0,0 +1,95 @@
+//
+// Copyright 2017 Ettus Research, a National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0
+//
+
+#ifndef INCLUDED_MPMD_XPORT_MGR_HPP
+#define INCLUDED_MPMD_XPORT_MGR_HPP
+
+#include "../device3/device3_impl.hpp"
+#include <uhd/types/dict.hpp>
+#include <memory>
+#include <map>
+#include <vector>
+#include <string>
+
+namespace uhd { namespace mpmd { namespace xport {
+
+/*! Return filtered subset from a device_addr_t
+ *
+ * The return dictionary will contain all key/value pairs from \p args
+ * where the key begins with \p prefix.
+ *
+ * \param args Bucket of key/value pairs
+ * \param prefix Key prefix to match against
+ */
+uhd::dict<std::string, std::string> filter_args(
+    const uhd::device_addr_t& args,
+    const std::string& prefix
+);
+
+/*! MPMD Transport Manager
+ *
+ * A transport manager is an object which sets up a physical connection to a
+ * CHDR device. Its implementation is specific to the underlying transport
+ * medium. For example, if the medium is Ethernet/UDP, this class will create
+ * sockets.
+ */
+class mpmd_xport_mgr
+{
+public:
+    using uptr = std::unique_ptr<mpmd_xport_mgr>;
+    using xport_info_t = std::map<std::string, std::string>;
+    using xport_info_list_t = std::vector<std::map<std::string, std::string>>;
+
+    /*! Return a reference to a transport manager
+     *
+     * \param mb_args Additional args from the motherboard. These may contain
+     *                transport-related args (e.g., "recv_buff_size") which
+     *                can be relevant to the underlying implementation.
+     *
+     * \returns Reference to manager object
+     * \throws uhd::key_error if \p xport_medium is not supported. The ctor of
+     *         the underlying class that is requested can also throw.
+     */
+    static uptr make(
+        const uhd::device_addr_t& mb_args
+    );
+
+    /*! Create a transports object
+     *
+     * Implementation details depend on the underlying implementation.
+     * In general, the implementations will follow the following recipe:
+     * 1. Pick a suitable element from \p xport_info_list
+     * 2. Do whatever system calls are necessary to create the physical
+     *    transport; to do so, call the underlying implementation (UDP or
+     *    whatever)
+     * 3. Update the selected element from xport_info_list
+     * 5. Return results
+     *
+     * \param xport_info_list List of possible options to choose from. Every
+     *                        element of this argument needs to have the same
+     *                        "type" key (e.g., they all need to be "UDP").
+     * \param xport_type Transport type (CTRL, RX_DATA, ...)
+     * \param xport_args Arbitrary additional transport args. These could come
+     *                   from the user, or other places.
+     * \param xport_info_out The updated dictionary from xport_info_list that
+     *                       was eventually chosen
+     *
+     * \returns The both_xports_t object containing the actual transport info,
+     *          and xport_info_out contains the updated transport option info.
+     *          The latter needs to get sent back to MPM to complete the
+     *          transport handshake.
+     */
+    virtual both_xports_t make_transport(
+        const xport_info_list_t &xport_info_list,
+        const usrp::device3_impl::xport_type_t xport_type,
+        const uhd::device_addr_t& xport_args,
+        xport_info_t& xport_info_out
+    ) = 0;
+};
+
+}}} /* namespace uhd::mpmd::xport */
+
+#endif /* INCLUDED_MPMD_XPORT_MGR_HPP */