uhd: add udp boost asio implementation of transport interface

7 files changed, 176 insertions, 195 deletions

diff --git a/host/lib/transport/CMakeLists.txt b/host/lib/transport/CMakeLists.txt
index a9663c89a..003beeee4 100644
--- a/host/lib/transport/CMakeLists.txt
+++ b/host/lib/transport/CMakeLists.txt
@@ -81,8 +81,10 @@ set_source_files_properties(
 ########################################################################
 if(WIN32)
     LIBUHD_APPEND_SOURCES(${CMAKE_CURRENT_SOURCE_DIR}/udp_wsa_zero_copy.cpp)
+    LIBUHD_APPEND_SOURCES(${CMAKE_CURRENT_SOURCE_DIR}/udp_boost_asio_link.cpp)
 else()
     LIBUHD_APPEND_SOURCES(${CMAKE_CURRENT_SOURCE_DIR}/udp_zero_copy.cpp)
+    LIBUHD_APPEND_SOURCES(${CMAKE_CURRENT_SOURCE_DIR}/udp_boost_asio_link.cpp)
 endif()
 
 #On windows, the boost asio implementation uses the winsock2 library.
diff --git a/host/lib/transport/tcp_zero_copy.cpp b/host/lib/transport/tcp_zero_copy.cpp
index 5cb713427..01bca900f 100644
--- a/host/lib/transport/tcp_zero_copy.cpp
+++ b/host/lib/transport/tcp_zero_copy.cpp
@@ -5,11 +5,11 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 
-#include "udp_common.hpp"
 #include <uhd/transport/buffer_pool.hpp>
 #include <uhd/transport/tcp_zero_copy.hpp>
 #include <uhd/utils/log.hpp>
 #include <uhdlib/utils/atomic.hpp>
+#include <uhdlib/transport/udp_common.hpp>
 #include <boost/format.hpp>
 #include <boost/make_shared.hpp>
 #include <chrono>
@@ -52,8 +52,9 @@ public:
             return make(this, _mem, size_t(_len));
         }
 #endif
+        const int32_t timeout_ms = static_cast<int32_t>(timeout * 1000);
 
-        if (wait_for_recv_ready(_sock_fd, timeout)) {
+        if (wait_for_recv_ready(_sock_fd, timeout_ms)) {
             _len = ::recv(_sock_fd, (char*)_mem, _frame_size, 0);
             index++; // advances the caller's buffer
             return make(this, _mem, size_t(_len));
diff --git a/host/lib/transport/udp_boost_asio_link.cpp b/host/lib/transport/udp_boost_asio_link.cpp
new file mode 100644
index 000000000..95d68ba91
--- /dev/null
+++ b/host/lib/transport/udp_boost_asio_link.cpp
@@ -0,0 +1,126 @@
+//
+// Copyright 2019 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#include <uhd/utils/log.hpp>
+#include <uhdlib/transport/udp_boost_asio_link.hpp>
+#include <boost/format.hpp>
+
+using namespace uhd::transport;
+
+namespace asio = boost::asio;
+
+udp_boost_asio_link::udp_boost_asio_link(
+    const std::string& addr, const std::string& port, const link_params_t& params)
+    : recv_link_base_t(params.num_recv_frames, params.recv_frame_size)
+    , send_link_base_t(params.num_send_frames, params.send_frame_size)
+    , _recv_memory_pool(buffer_pool::make(params.num_recv_frames, params.recv_frame_size))
+    , _send_memory_pool(buffer_pool::make(params.num_send_frames, params.send_frame_size))
+{
+    for (size_t i = 0; i < params.num_recv_frames; i++) {
+        _recv_buffs.push_back(udp_boost_asio_frame_buff(_recv_memory_pool->at(i)));
+    }
+
+    for (size_t i = 0; i < params.num_send_frames; i++) {
+        _send_buffs.push_back(udp_boost_asio_frame_buff(_send_memory_pool->at(i)));
+    }
+
+    for (auto& buff : _recv_buffs) {
+        recv_link_base_t::preload_free_buff(&buff);
+    }
+
+    for (auto& buff : _send_buffs) {
+        send_link_base_t::preload_free_buff(&buff);
+    }
+
+    // create, open, and connect the socket
+    _socket  = open_udp_socket(addr, port, _io_service);
+    _sock_fd = _socket->native_handle();
+
+    UHD_LOGGER_TRACE("UDP")
+        << boost::format("Created UDP link to %s:%s") % addr % port;
+    UHD_LOGGER_TRACE("UDP") << boost::format("Local UDP socket endpoint: %s:%s")
+        % get_local_addr() % get_local_port();
+}
+
+uint16_t udp_boost_asio_link::get_local_port() const
+{
+    return _socket->local_endpoint().port();
+}
+
+std::string udp_boost_asio_link::get_local_addr() const
+{
+    return _socket->local_endpoint().address().to_string();
+}
+
+size_t udp_boost_asio_link::resize_recv_socket_buffer(size_t num_bytes)
+{
+    return resize_udp_socket_buffer<asio::socket_base::receive_buffer_size>(
+        _socket, num_bytes);
+}
+
+size_t udp_boost_asio_link::resize_send_socket_buffer(size_t num_bytes)
+{
+    return resize_udp_socket_buffer<asio::socket_base::send_buffer_size>(
+        _socket, num_bytes);
+}
+
+udp_boost_asio_link::sptr udp_boost_asio_link::make(const std::string& addr,
+    const std::string& port,
+    const link_params_t& params,
+    size_t& recv_socket_buff_size,
+    size_t& send_socket_buff_size)
+{
+    UHD_ASSERT_THROW(params.num_recv_frames != 0);
+    UHD_ASSERT_THROW(params.num_send_frames != 0);
+    UHD_ASSERT_THROW(params.recv_frame_size != 0);
+    UHD_ASSERT_THROW(params.send_frame_size != 0);
+    UHD_ASSERT_THROW(params.recv_buff_size != 0);
+    UHD_ASSERT_THROW(params.send_buff_size != 0);
+
+#if defined(UHD_PLATFORM_MACOS) || defined(UHD_PLATFORM_BSD)
+    // limit buffer size on macos to avoid the warning issued by
+    // resize_buff_helper
+    if (params.recv_buff_size > MAX_BUFF_SIZE_ETH_MACOS) {
+        params.recv_buff_size = MAX_BUFF_SIZE_ETH_MACOS;
+    }
+    if (params.send_buff_size > MAX_BUFF_SIZE_ETH_MACOS) {
+        params.send_buff_size = MAX_BUFF_SIZE_ETH_MACOS;
+    }
+#endif
+
+    udp_boost_asio_link::sptr link(
+        new udp_boost_asio_link(addr, port, params));
+
+    // call the helper to resize send and recv buffers
+
+    recv_socket_buff_size = resize_udp_socket_buffer_with_warning(
+        [link](size_t size) { return link->resize_recv_socket_buffer(size); },
+        params.recv_buff_size,
+        "recv");
+    send_socket_buff_size = resize_udp_socket_buffer_with_warning(
+        [link](size_t size) { return link->resize_send_socket_buffer(size); },
+        params.send_buff_size,
+        "send");
+
+    if (recv_socket_buff_size < params.num_recv_frames * MAX_ETHERNET_MTU) {
+        UHD_LOG_WARNING("UDP",
+            "The current recv_buff_size of "
+                << params.recv_buff_size
+                << " is less than the minimum recommended size of "
+                << params.num_recv_frames * MAX_ETHERNET_MTU
+                << " and may result in dropped packets on some NICs");
+    }
+    if (send_socket_buff_size < params.num_send_frames * MAX_ETHERNET_MTU) {
+        UHD_LOG_WARNING("UDP",
+            "The current send_buff_size of "
+                << params.send_buff_size
+                << " is less than the minimum recommended size of "
+                << params.num_send_frames * MAX_ETHERNET_MTU
+                << " and may result in dropped packets on some NICs");
+    }
+
+    return link;
+}
diff --git a/host/lib/transport/udp_common.hpp b/host/lib/transport/udp_common.hpp
deleted file mode 100644
index f320e3d85..000000000
--- a/host/lib/transport/udp_common.hpp
+++ /dev/null
@@ -1,71 +0,0 @@
-//
-// Copyright 2011 Ettus Research LLC
-// Copyright 2018 Ettus Research, a National Instruments Company
-//
-// SPDX-License-Identifier: GPL-3.0-or-later
-//
-
-#ifndef INCLUDED_LIBUHD_TRANSPORT_VRT_PACKET_HANDLER_HPP
-#define INCLUDED_LIBUHD_TRANSPORT_VRT_PACKET_HANDLER_HPP
-
-#include <uhd/config.hpp>
-#include <boost/asio.hpp>
-
-namespace uhd { namespace transport {
-
-// Jumbo frames can be up to 9600 bytes;
-static const size_t MAX_ETHERNET_MTU = 9600;
-
-#if defined(UHD_PLATFORM_MACOS) || defined(UHD_PLATFORM_BSD)
-// MacOS limits socket buffer size to 1 Mib
-static const size_t MAX_BUFF_SIZE_ETH_MACOS = 0x100000; // 1Mib
-#endif
-
-typedef boost::shared_ptr<boost::asio::ip::udp::socket> socket_sptr;
-
-/*!
- * Wait for the socket to become ready for a receive operation.
- * \param sock_fd the open socket file descriptor
- * \param timeout the timeout duration in seconds
- * \return true when the socket is ready for receive
- */
-UHD_INLINE bool wait_for_recv_ready(int sock_fd, double timeout)
-{
-#ifdef UHD_PLATFORM_WIN32 // select is more portable than poll unfortunately
-    // setup timeval for timeout
-    timeval tv;
-    // If the tv_usec > 1 second on some platforms, select will
-    // error EINVAL: An invalid timeout interval was specified.
-    tv.tv_sec  = int(timeout);
-    tv.tv_usec = int(timeout * 1000000) % 1000000;
-
-    // setup rset for timeout
-    fd_set rset;
-    FD_ZERO(&rset);
-    FD_SET(sock_fd, &rset);
-
-// http://www.gnu.org/s/hello/manual/libc/Interrupted-Primitives.html
-// This macro is provided with gcc to properly deal with EINTR.
-// If not provided, define an empty macro, assume that is OK
-#    ifndef TEMP_FAILURE_RETRY
-#        define TEMP_FAILURE_RETRY(x) (x)
-#    endif
-
-    // call select with timeout on receive socket
-    return TEMP_FAILURE_RETRY(::select(sock_fd + 1, &rset, NULL, NULL, &tv)) > 0;
-#else
-    // calculate the total timeout in milliseconds (from seconds)
-    int total_timeout = int(timeout * 1000);
-
-    pollfd pfd_read;
-    pfd_read.fd     = sock_fd;
-    pfd_read.events = POLLIN;
-
-    // call poll with timeout on receive socket
-    return ::poll(&pfd_read, 1, total_timeout) > 0;
-#endif
-}
-
-}} // namespace uhd::transport
-
-#endif /* INCLUDED_LIBUHD_TRANSPORT_VRT_PACKET_HANDLER_HPP */
diff --git a/host/lib/transport/udp_simple.cpp b/host/lib/transport/udp_simple.cpp
index 48d7b500e..e10dff7f8 100644
--- a/host/lib/transport/udp_simple.cpp
+++ b/host/lib/transport/udp_simple.cpp
@@ -5,9 +5,9 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 
-#include "udp_common.hpp"
 #include <uhd/transport/udp_simple.hpp>
 #include <uhd/utils/log.hpp>
+#include <uhdlib/transport/udp_common.hpp>
 #include <boost/format.hpp>
 
 using namespace uhd::transport;
@@ -53,7 +53,9 @@ public:
 
     size_t recv(const asio::mutable_buffer& buff, double timeout)
     {
-        if (not wait_for_recv_ready(_socket->native_handle(), timeout))
+        const int32_t timeout_ms = static_cast<int32_t>(timeout * 1000);
+
+        if (not wait_for_recv_ready(_socket->native_handle(), timeout_ms))
             return 0;
         return _socket->receive_from(asio::buffer(buff), _recv_endpoint);
     }
diff --git a/host/lib/transport/udp_wsa_zero_copy.cpp b/host/lib/transport/udp_wsa_zero_copy.cpp
index 8f83ea5ef..36837cda4 100644
--- a/host/lib/transport/udp_wsa_zero_copy.cpp
+++ b/host/lib/transport/udp_wsa_zero_copy.cpp
@@ -5,11 +5,11 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 
-#include "udp_common.hpp"
 #include <uhd/transport/buffer_pool.hpp>
 #include <uhd/transport/udp_simple.hpp> //mtu
 #include <uhd/transport/udp_zero_copy.hpp>
 #include <uhd/utils/log.hpp>
+#include <uhdlib/transport/udp_common.hpp>
 #include <boost/format.hpp>
 #include <vector>
 
diff --git a/host/lib/transport/udp_zero_copy.cpp b/host/lib/transport/udp_zero_copy.cpp
index e3df80da6..44df9526d 100644
--- a/host/lib/transport/udp_zero_copy.cpp
+++ b/host/lib/transport/udp_zero_copy.cpp
@@ -5,11 +5,10 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 //
 
-#include "udp_common.hpp"
 #include <uhd/transport/buffer_pool.hpp>
-#include <uhd/transport/udp_simple.hpp> //mtu
 #include <uhd/transport/udp_zero_copy.hpp>
 #include <uhd/utils/log.hpp>
+#include <uhdlib/transport/udp_common.hpp>
 #include <uhdlib/utils/atomic.hpp>
 #include <boost/format.hpp>
 #include <boost/make_shared.hpp>
@@ -19,12 +18,8 @@
 
 using namespace uhd;
 using namespace uhd::transport;
-namespace asio                                    = boost::asio;
-constexpr size_t UDP_ZERO_COPY_DEFAULT_NUM_FRAMES = 1;
-constexpr size_t UDP_ZERO_COPY_DEFAULT_FRAME_SIZE =
-    1472; // Based on common 1500 byte MTU for 1GbE.
-constexpr size_t UDP_ZERO_COPY_DEFAULT_BUFF_SIZE =
-    2500000; // 20ms of data for 1GbE link (in bytes)
+namespace asio = boost::asio;
+
 /***********************************************************************
  * Check registry for correct fast-path setting (windows only)
  **********************************************************************/
@@ -80,22 +75,11 @@ public:
         if (not _claimer.claim_with_wait(timeout))
             return sptr();
 
-#ifdef MSG_DONTWAIT // try a non-blocking recv() if supported
-        _len = ::recv(_sock_fd, (char*)_mem, _frame_size, MSG_DONTWAIT);
-        if (_len > 0) {
-            index++; // advances the caller's buffer
-            return make(this, _mem, size_t(_len));
-        }
-#endif
+        const int32_t timeout_ms = static_cast<int32_t>(timeout * 1000);
+        _len = recv_udp_packet(_sock_fd, _mem, _frame_size, timeout_ms);
 
-        if (wait_for_recv_ready(_sock_fd, timeout)) {
-            _len = ::recv(_sock_fd, (char*)_mem, _frame_size, 0);
-            if (_len == 0)
-                throw uhd::io_error("socket closed");
-            if (_len < 0)
-                throw uhd::io_error(
-                    str(boost::format("recv error on socket: %s") % strerror(errno)));
-            index++; // advances the caller's buffer
+        if (_len > 0) {
+            index++;
             return make(this, _mem, size_t(_len));
         }
 
@@ -125,23 +109,7 @@ public:
 
     void release(void)
     {
-        // Retry logic because send may fail with ENOBUFS.
-        // This is known to occur at least on some OSX systems.
-        // But it should be safe to always check for the error.
-        while (true) {
-            const ssize_t ret = ::send(_sock_fd, (const char*)_mem, size(), 0);
-            if (ret == ssize_t(size()))
-                break;
-            if (ret == -1 and errno == ENOBUFS) {
-                std::this_thread::sleep_for(std::chrono::microseconds(1));
-                continue; // try to send again
-            }
-            if (ret == -1) {
-                throw uhd::io_error(
-                    str(boost::format("send error on socket: %s") % strerror(errno)));
-            }
-            UHD_ASSERT_THROW(ret == ssize_t(size()));
-        }
+        send_udp_packet(_sock_fd, _mem, size());
         _claimer.release();
     }
 
@@ -193,15 +161,7 @@ public:
         check_registry_for_fast_send_threshold(this->get_send_frame_size());
 #endif /*CHECK_REG_SEND_THRESH*/
 
-        // resolve the address
-        asio::ip::udp::resolver resolver(_io_service);
-        asio::ip::udp::resolver::query query(asio::ip::udp::v4(), addr, port);
-        asio::ip::udp::endpoint receiver_endpoint = *resolver.resolve(query);
-
-        // create, open, and connect the socket
-        _socket = socket_sptr(new asio::ip::udp::socket(_io_service));
-        _socket->open(asio::ip::udp::v4());
-        _socket->connect(receiver_endpoint);
+        _socket  = open_udp_socket(addr, port, _io_service);
         _sock_fd = _socket->native_handle();
 
         UHD_LOGGER_TRACE("UDP") << boost::format("Local UDP socket endpoint: %s:%s")
@@ -220,24 +180,16 @@ public:
         }
     }
 
-    // get size for internal socket buffer
-    template <typename Opt> size_t get_buff_size(void) const
+    size_t resize_send_socket_buffer(size_t num_bytes)
     {
-        Opt option;
-        _socket->get_option(option);
-        return option.value();
+        return resize_udp_socket_buffer<asio::socket_base::send_buffer_size>(
+            _socket, num_bytes);
     }
 
-    // set size for internal socket buffer
-    template <typename Opt> size_t resize_buff(size_t num_bytes)
+    size_t resize_recv_socket_buffer(size_t num_bytes)
     {
-#if defined(UHD_PLATFORM_MACOS) || defined(UHD_PLATFORM_BSD)
-        // limit buffer resize on macos or it will error
-        num_bytes = std::min(num_bytes, MAX_BUFF_SIZE_ETH_MACOS);
-#endif
-        Opt option(num_bytes);
-        _socket->set_option(option);
-        return get_buff_size<Opt>();
+        return resize_udp_socket_buffer<asio::socket_base::receive_buffer_size>(
+            _socket, num_bytes);
     }
 
     /*******************************************************************
@@ -308,37 +260,6 @@ private:
 /***********************************************************************
  * UDP zero copy make function
  **********************************************************************/
-template <typename Opt>
-static size_t resize_buff_helper(udp_zero_copy_asio_impl::sptr udp_trans,
-    const size_t target_size,
-    const std::string& name)
-{
-    size_t actual_size = 0;
-    std::string help_message;
-#if defined(UHD_PLATFORM_LINUX)
-    help_message = str(boost::format("Please run: sudo sysctl -w net.core.%smem_max=%d")
-                       % ((name == "recv") ? "r" : "w") % target_size);
-#endif /*defined(UHD_PLATFORM_LINUX)*/
-
-    // resize the buffer if size was provided
-    if (target_size > 0) {
-        actual_size = udp_trans->resize_buff<Opt>(target_size);
-        UHD_LOGGER_TRACE("UDP")
-            << boost::format("Target/actual %s sock buff size: %d/%d bytes") % name
-                   % target_size % actual_size;
-        if (actual_size < target_size)
-            UHD_LOGGER_WARNING("UDP")
-                << boost::format(
-                       "The %s buffer could not be resized sufficiently.\n"
-                       "Target sock buff size: %d bytes.\n"
-                       "Actual sock buff size: %d bytes.\n"
-                       "See the transport application notes on buffer resizing.\n%s")
-                       % name % target_size % actual_size % help_message;
-    }
-
-    return actual_size;
-}
-
 udp_zero_copy::sptr udp_zero_copy::make(const std::string& addr,
     const std::string& port,
     const zero_copy_xport_params& default_buff_args,
@@ -362,26 +283,24 @@ udp_zero_copy::sptr udp_zero_copy::make(const std::string& addr,
         size_t(hints.cast<double>("send_buff_size", default_buff_args.send_buff_size));
 
     if (xport_params.num_recv_frames == 0) {
-        UHD_LOG_TRACE("UDP",
-            "Default value for num_recv_frames: " << UDP_ZERO_COPY_DEFAULT_NUM_FRAMES);
-        xport_params.num_recv_frames = UDP_ZERO_COPY_DEFAULT_NUM_FRAMES;
+        UHD_LOG_TRACE(
+            "UDP", "Default value for num_recv_frames: " << UDP_DEFAULT_NUM_FRAMES);
+        xport_params.num_recv_frames = UDP_DEFAULT_NUM_FRAMES;
     }
     if (xport_params.num_send_frames == 0) {
-        UHD_LOG_TRACE("UDP",
-            "Default value for no num_send_frames: " << UDP_ZERO_COPY_DEFAULT_NUM_FRAMES);
-        xport_params.num_send_frames = UDP_ZERO_COPY_DEFAULT_NUM_FRAMES;
+        UHD_LOG_TRACE(
+            "UDP", "Default value for no num_send_frames: " << UDP_DEFAULT_NUM_FRAMES);
+        xport_params.num_send_frames = UDP_DEFAULT_NUM_FRAMES;
     }
     if (xport_params.recv_frame_size == 0) {
         UHD_LOG_TRACE("UDP",
-            "Using default value for  recv_frame_size: "
-                << UDP_ZERO_COPY_DEFAULT_FRAME_SIZE);
-        xport_params.recv_frame_size = UDP_ZERO_COPY_DEFAULT_FRAME_SIZE;
+            "Using default value for  recv_frame_size: " << UDP_DEFAULT_FRAME_SIZE);
+        xport_params.recv_frame_size = UDP_DEFAULT_FRAME_SIZE;
     }
     if (xport_params.send_frame_size == 0) {
-        UHD_LOG_TRACE("UDP",
-            "Using default value for send_frame_size, "
-                << UDP_ZERO_COPY_DEFAULT_FRAME_SIZE);
-        xport_params.send_frame_size = UDP_ZERO_COPY_DEFAULT_FRAME_SIZE;
+        UHD_LOG_TRACE(
+            "UDP", "Using default value for send_frame_size, " << UDP_DEFAULT_FRAME_SIZE);
+        xport_params.send_frame_size = UDP_DEFAULT_FRAME_SIZE;
     }
 
     UHD_LOG_TRACE("UDP",
@@ -391,15 +310,15 @@ udp_zero_copy::sptr udp_zero_copy::make(const std::string& addr,
 
     if (xport_params.recv_buff_size == 0) {
         UHD_LOG_TRACE("UDP", "Using default value for recv_buff_size");
-        xport_params.recv_buff_size = std::max(UDP_ZERO_COPY_DEFAULT_BUFF_SIZE,
-            xport_params.num_recv_frames * MAX_ETHERNET_MTU);
+        xport_params.recv_buff_size = std::max(
+            UDP_DEFAULT_BUFF_SIZE, xport_params.num_recv_frames * MAX_ETHERNET_MTU);
         UHD_LOG_TRACE("UDP",
             "Using default value for recv_buff_size" << xport_params.recv_buff_size);
     }
     if (xport_params.send_buff_size == 0) {
         UHD_LOG_TRACE("UDP", "default_buff_args has no send_buff_size");
-        xport_params.send_buff_size = std::max(UDP_ZERO_COPY_DEFAULT_BUFF_SIZE,
-            xport_params.num_send_frames * MAX_ETHERNET_MTU);
+        xport_params.send_buff_size = std::max(
+            UDP_DEFAULT_BUFF_SIZE, xport_params.num_send_frames * MAX_ETHERNET_MTU);
     }
 
 #if defined(UHD_PLATFORM_MACOS) || defined(UHD_PLATFORM_BSD)
@@ -419,18 +338,20 @@ udp_zero_copy::sptr udp_zero_copy::make(const std::string& addr,
         new udp_zero_copy_asio_impl(addr, port, xport_params));
 
     // call the helper to resize send and recv buffers
-    buff_params_out.recv_buff_size =
-        resize_buff_helper<asio::socket_base::receive_buffer_size>(
-            udp_trans, xport_params.recv_buff_size, "recv");
-    buff_params_out.send_buff_size =
-        resize_buff_helper<asio::socket_base::send_buffer_size>(
-            udp_trans, xport_params.send_buff_size, "send");
+    buff_params_out.recv_buff_size = resize_udp_socket_buffer_with_warning(
+        [udp_trans](size_t size) { return udp_trans->resize_recv_socket_buffer(size); },
+        xport_params.recv_buff_size,
+        "recv");
+    buff_params_out.send_buff_size = resize_udp_socket_buffer_with_warning(
+        [udp_trans](size_t size) { return udp_trans->resize_send_socket_buffer(size); },
+        xport_params.send_buff_size,
+        "send");
 
     if (buff_params_out.recv_buff_size
         < xport_params.num_recv_frames * MAX_ETHERNET_MTU) {
         UHD_LOG_WARNING("UDP",
             "The current recv_buff_size of "
-                << buff_params_out.recv_buff_size
+                << xport_params.recv_buff_size
                 << " is less than the minimum recommended size of "
                 << xport_params.num_recv_frames * MAX_ETHERNET_MTU
                 << " and may result in dropped packets on some NICs");
@@ -439,7 +360,7 @@ udp_zero_copy::sptr udp_zero_copy::make(const std::string& addr,
         < xport_params.num_send_frames * MAX_ETHERNET_MTU) {
         UHD_LOG_WARNING("UDP",
             "The current send_buff_size of "
-                << buff_params_out.send_buff_size
+                << xport_params.send_buff_size
                 << " is less than the minimum recommended size of "
                 << xport_params.num_send_frames * MAX_ETHERNET_MTU
                 << " and may result in dropped packets on some NICs");