4 files changed, 16 insertions, 15 deletions

diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index 25fd1c484..8314cf9ae 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -242,16 +242,6 @@ void usrp2_impl::io_impl::recv_pirate_loop(
  * Helper Functions
  **********************************************************************/
 void usrp2_impl::io_init(void){
-    //send a small data packet so the usrp2 knows the udp source port
-    BOOST_FOREACH(zero_copy_if::sptr data_transport, _data_transports){
-        managed_send_buffer::sptr send_buff = data_transport->get_send_buff();
-        static const boost::uint32_t data[2] = {
-            uhd::htonx(boost::uint32_t(0 /* don't care seq num */)),
-            uhd::htonx(boost::uint32_t(USRP2_INVALID_VRT_HEADER))
-        };
-        std::memcpy(send_buff->cast<void*>(), &data, sizeof(data));
-        send_buff->commit(sizeof(data));
-    }
 
     //the assumption is that all data transports should be identical
     const size_t num_recv_frames = _data_transports.front()->get_num_recv_frames();
diff --git a/host/lib/usrp/usrp2/mboard_impl.cpp b/host/lib/usrp/usrp2/mboard_impl.cpp
index 5210eee94..8f3ae5c1b 100644
--- a/host/lib/usrp/usrp2/mboard_impl.cpp
+++ b/host/lib/usrp/usrp2/mboard_impl.cpp
@@ -21,6 +21,7 @@
 #include <uhd/usrp/dsp_utils.hpp>
 #include <uhd/usrp/mboard_props.hpp>
 #include <uhd/utils/assert.hpp>
+#include <uhd/utils/byteswap.hpp>
 #include <uhd/utils/algorithm.hpp>
 #include <uhd/types/mac_addr.hpp>
 #include <uhd/types/dict.hpp>
@@ -38,13 +39,24 @@ using namespace uhd::usrp;
 usrp2_mboard_impl::usrp2_mboard_impl(
     size_t index,
     transport::udp_simple::sptr ctrl_transport,
+    transport::zero_copy_if::sptr data_transport,
     size_t recv_samps_per_packet,
-    size_t send_bytes_per_packet,
     const device_addr_t &flow_control_hints
 ):
     _index(index),
     _recv_samps_per_packet(recv_samps_per_packet)
 {
+    //Send a small data packet so the usrp2 knows the udp source port.
+    //This setup must happen before further initialization occurs
+    //or the async update packets will cause ICMP destination unreachable.
+    transport::managed_send_buffer::sptr send_buff = data_transport->get_send_buff();
+    static const boost::uint32_t data[2] = {
+        uhd::htonx(boost::uint32_t(0 /* don't care seq num */)),
+        uhd::htonx(boost::uint32_t(USRP2_INVALID_VRT_HEADER))
+    };
+    std::memcpy(send_buff->cast<void*>(), &data, sizeof(data));
+    send_buff->commit(sizeof(data));
+
     //make a new interface for usrp2 stuff
     _iface = usrp2_iface::make(ctrl_transport);
 
@@ -98,7 +110,7 @@ usrp2_mboard_impl::usrp2_mboard_impl(
 
     //setting the packets per update
     const double ups_per_fifo = flow_control_hints.cast<double>("ups_per_fifo", 8);
-    const size_t packets_per_up = size_t(usrp2_impl::sram_bytes/ups_per_fifo/send_bytes_per_packet);
+    const size_t packets_per_up = size_t(usrp2_impl::sram_bytes/ups_per_fifo/data_transport->get_send_frame_size());
     _iface->poke32(U2_REG_TX_CTRL_PACKETS_PER_UP, U2_FLAG_TX_CTRL_UP_ENB | packets_per_up);
 
     //init the ddc
diff --git a/host/lib/usrp/usrp2/usrp2_impl.cpp b/host/lib/usrp/usrp2/usrp2_impl.cpp
index e271f839c..afc69f703 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.cpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.cpp
@@ -171,9 +171,8 @@ usrp2_impl::usrp2_impl(
     //create a new mboard handler for each control transport
     for(size_t i = 0; i < ctrl_transports.size(); i++){
         _mboards.push_back(usrp2_mboard_impl::sptr(new usrp2_mboard_impl(
-            i, ctrl_transports[i],
+            i, ctrl_transports[i], data_transports[i],
             this->get_max_recv_samps_per_packet(),
-            _data_transports[i]->get_send_frame_size(),
             flow_control_hints
         )));
         //use an empty name when there is only one mboard
diff --git a/host/lib/usrp/usrp2/usrp2_impl.hpp b/host/lib/usrp/usrp2/usrp2_impl.hpp
index 3aa6e9cd5..2531bd6cb 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.hpp
@@ -84,8 +84,8 @@ public:
     usrp2_mboard_impl(
         size_t index,
         uhd::transport::udp_simple::sptr,
+        uhd::transport::zero_copy_if::sptr,
         size_t recv_samps_per_packet,
-        size_t send_bytes_per_packet,
         const uhd::device_addr_t &flow_control_hints
     );
     ~usrp2_mboard_impl(void);