Added IF data io handing within the usrp2 impl.

It packs and unpacks vrt headers/metadata.
NOT YET TESTED IN ANY WAY...

11 files changed, 299 insertions, 190 deletions

diff --git a/host/include/uhd/CMakeLists.txt b/host/include/uhd/CMakeLists.txt
index e87f74291..f4fb96786 100644
--- a/host/include/uhd/CMakeLists.txt
+++ b/host/include/uhd/CMakeLists.txt
@@ -26,7 +26,6 @@ INSTALL(FILES
     gain_handler.hpp
     metadata.hpp
     props.hpp
-    shared_iovec.hpp
     time_spec.hpp
     utils.hpp
     wax.hpp
diff --git a/host/include/uhd/device.hpp b/host/include/uhd/device.hpp
index da58d4f85..596a98bc4 100644
--- a/host/include/uhd/device.hpp
+++ b/host/include/uhd/device.hpp
@@ -77,7 +77,7 @@ public:
      * \param buff a buffer pointing to some read-only memory
      * \param metadata data describing the buffer's contents
      * \param the type of data loaded in the buffer (32fc, 16sc)
-     * \return the number of bytes sent
+     * \return the number of samples sent
      */
     virtual size_t send(
         const boost::asio::const_buffer &buff,
@@ -91,7 +91,7 @@ public:
      * \param buff the buffer to fill with IF data
      * \param metadata data to fill describing the buffer
      * \param the type of data to fill into the buffer (32fc, 16sc)
-     * \return the number of bytes received
+     * \return the number of samples received
      */
     virtual size_t recv(
         const boost::asio::mutable_buffer &buff,
diff --git a/host/include/uhd/metadata.hpp b/host/include/uhd/metadata.hpp
index 43b91d1b0..70842e7bc 100644
--- a/host/include/uhd/metadata.hpp
+++ b/host/include/uhd/metadata.hpp
@@ -30,13 +30,17 @@ namespace uhd{
  */
 struct metadata_t{
     uint32_t stream_id;
+    bool has_stream_id;
     time_spec_t time_spec;
+    bool has_time_spec;
     bool start_of_burst;
     bool end_of_burst;
 
     metadata_t(void){
         stream_id = 0;
+        has_stream_id = false;
         time_spec = time_spec_t();
+        has_time_spec = false;
         start_of_burst = false;
         end_of_burst = false;
     }
diff --git a/host/include/uhd/shared_iovec.hpp b/host/include/uhd/shared_iovec.hpp
deleted file mode 100644
index a120e55d5..000000000
--- a/host/include/uhd/shared_iovec.hpp
+++ /dev/null
@@ -1,54 +0,0 @@
-//
-// Copyright 2010 Ettus Research LLC
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-//
-
-#ifndef INCLUDED_UHD_SHARED_IOVEC_HPP
-#define INCLUDED_UHD_SHARED_IOVEC_HPP
-
-#include <boost/shared_array.hpp>
-#include <stdint.h>
-
-namespace uhd{
-
-/*!
- * A shared iovec contains a shared array and its length.
- * Creating a new shared iovec allocates new memory.
- * This memory is freed when all copies are destroyed.
- */
-class shared_iovec{
-public:
-    /*!
-     * Create a shared iovec and allocate memory.
-     * \param len the length in bytes
-     */
-    shared_iovec(size_t len=0);
-
-    /*!
-     * Destroy a shared iovec.
-     * Will not free the memory unless this is the last copy.
-     */
-    ~shared_iovec(void);
-
-    void *base;
-    size_t len;
-
-private:
-    boost::shared_array<uint8_t> _shared_array;
-};
-
-} //namespace uhd
-
-#endif /* INCLUDED_UHD_SHARED_IOVEC_HPP */
diff --git a/host/include/uhd/transport/udp.hpp b/host/include/uhd/transport/udp.hpp
index 07d84e62a..8c6fb096f 100644
--- a/host/include/uhd/transport/udp.hpp
+++ b/host/include/uhd/transport/udp.hpp
@@ -18,7 +18,6 @@
 #include <boost/asio.hpp>
 #include <boost/utility.hpp>
 #include <boost/shared_ptr.hpp>
-#include <uhd/shared_iovec.hpp>
 
 #ifndef INCLUDED_UHD_TRANSPORT_UDP_HPP
 #define INCLUDED_UHD_TRANSPORT_UDP_HPP
@@ -58,18 +57,18 @@ public:
     /*!
      * Receive a buffer. Write into the memory provided.
      * Returns empty when data is not available.
-     * \param buff a mutable buffer to receive into
+     * \param buffs a vector of asio buffers
      * \return the number of bytes received.
      */
-    virtual size_t recv(const boost::asio::mutable_buffer &buff) = 0;
+    virtual size_t recv(const std::vector<boost::asio::mutable_buffer> &buffs) = 0;
 
     /*!
-     * Receive a buffer. The memory is managed internally.
-     * Returns zero when data is not available.
-     * Calling recv will invalidate the buffer of the previous recv.
-     * \return a shared iovec with allocated memory
+     * Receive a buffer. Write into the memory provided.
+     * Returns empty when data is not available.
+     * \param buff a mutable buffer to receive into
+     * \return the number of bytes received.
      */
-    virtual uhd::shared_iovec recv(void) = 0;
+    virtual size_t recv(const boost::asio::mutable_buffer &buff) = 0;
 };
 
 }} //namespace
diff --git a/host/lib/CMakeLists.txt b/host/lib/CMakeLists.txt
index 5cf334678..253f45614 100644
--- a/host/lib/CMakeLists.txt
+++ b/host/lib/CMakeLists.txt
@@ -20,7 +20,6 @@ SET(libuhd_sources
     device.cpp
     device_addr.cpp
     gain_handler.cpp
-    shared_iovec.cpp
     uhd.cpp
     wax.cpp
     transport/udp.cpp
@@ -32,6 +31,7 @@ SET(libuhd_sources
     usrp/usrp2/dboard_impl.cpp
     usrp/usrp2/dboard_interface.cpp
     usrp/usrp2/dsp_impl.cpp
+    usrp/usrp2/io_impl.cpp
     usrp/usrp2/mboard_impl.cpp
     usrp/usrp2/usrp2_impl.cpp
 )
diff --git a/host/lib/shared_iovec.cpp b/host/lib/shared_iovec.cpp
deleted file mode 100644
index 60062fbf0..000000000
--- a/host/lib/shared_iovec.cpp
+++ /dev/null
@@ -1,28 +0,0 @@
-//
-// Copyright 2010 Ettus Research LLC
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-//
-
-#include <uhd/shared_iovec.hpp>
-
-uhd::shared_iovec::shared_iovec(size_t len_){
-    _shared_array = boost::shared_array<uint8_t>(new uint8_t[len_]);
-    base = _shared_array.get();
-    len = len_;
-}
-
-uhd::shared_iovec::~shared_iovec(void){
-    /* NOP */
-}
diff --git a/host/lib/transport/udp.cpp b/host/lib/transport/udp.cpp
index fca4dd7d6..878f71410 100644
--- a/host/lib/transport/udp.cpp
+++ b/host/lib/transport/udp.cpp
@@ -31,8 +31,8 @@ public:
     //send/recv
     size_t send(const std::vector<boost::asio::const_buffer> &buffs);
     size_t send(const boost::asio::const_buffer &buff);
+    size_t recv(const std::vector<boost::asio::mutable_buffer> &buffs);
     size_t recv(const boost::asio::mutable_buffer &buff);
-    uhd::shared_iovec recv(void);
 
 private:
     boost::asio::ip::udp::socket   *_socket;
@@ -87,20 +87,12 @@ size_t udp_impl::send(const boost::asio::const_buffer &buff){
     return _socket->send_to(boost::asio::buffer(buff), _receiver_endpoint);
 }
 
-size_t udp_impl::recv(const boost::asio::mutable_buffer &buff){
+size_t udp_impl::recv(const std::vector<boost::asio::mutable_buffer> &buffs){
     if (_socket->available() == 0) return 0;
-    return _socket->receive_from(boost::asio::buffer(buff), _sender_endpoint);
+    return _socket->receive_from(buffs, _sender_endpoint);
 }
 
-uhd::shared_iovec udp_impl::recv(void){
-    //allocate a buffer for the number of bytes available (could be zero)
-    uhd::shared_iovec iov(_socket->available());
-    //call recv only if data is available
-    if (iov.len != 0){
-        _socket->receive_from(
-            boost::asio::buffer(iov.base, iov.len),
-            _sender_endpoint
-        );
-    }
-    return iov;
+size_t udp_impl::recv(const boost::asio::mutable_buffer &buff){
+    if (_socket->available() == 0) return 0;
+    return _socket->receive_from(boost::asio::buffer(buff), _sender_endpoint);
 }
diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
new file mode 100644
index 000000000..fbea71f85
--- /dev/null
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -0,0 +1,261 @@
+//
+// Copyright 2010 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <complex>
+#include <boost/shared_array.hpp>
+#include <boost/format.hpp>
+#include "usrp2_impl.hpp"
+
+using namespace uhd;
+using namespace uhd::usrp;
+
+/***********************************************************************
+ * Constants
+ **********************************************************************/
+typedef std::complex<float>   fc32_t;
+typedef std::complex<int16_t> sc16_t;
+
+static const float float_scale_factor = pow(2.0, 15);
+
+//max length with header, stream id, seconds, fractional seconds
+static const size_t max_vrt_header_words = 5;
+
+/***********************************************************************
+ * Helper Functions
+ **********************************************************************/
+
+/*static void pack_vrt_header(
+    size_t num_data_words,            //input
+    const uhd::metadata_t &metadata,  //input
+    uint32_t *vrt_header,             //output
+    size_t &vrt_header_words          //output
+){
+    //
+}
+
+static void unpack_vrt_header(
+    size_t &num_data_words,           //output
+    uhd::metadata_t &metadata,        //output
+    const uint32_t *vrt_header,       //input
+    size_t &vrt_header_words          //output
+){
+    //
+}*/
+
+static inline void host_floats_to_usrp2_shorts(
+    int16_t *usrp2_shorts,
+    const float *host_floats,
+    size_t num_samps
+){
+    for(size_t i = 0; i < num_samps; i++){
+        usrp2_shorts[i] = htons(int16_t(host_floats[i]*float_scale_factor));
+    }
+}
+
+static inline void usrp2_shorts_to_host_floats(
+    float *host_floats,
+    const int16_t *usrp2_shorts,
+    size_t num_samps
+){
+    for(size_t i = 0; i < num_samps; i++){
+        host_floats[i] = float(ntohs(usrp2_shorts[i])/float_scale_factor);
+    }
+}
+
+static inline void host_shorts_to_usrp2_shorts(
+    int16_t *usrp2_shorts,
+    const int16_t *host_shorts,
+    size_t num_samps
+){
+    for(size_t i = 0; i < num_samps; i++){
+        usrp2_shorts[i] = htons(host_shorts[i]);
+    }
+}
+
+static inline void usrp2_shorts_to_host_shorts(
+    int16_t *host_shorts,
+    const int16_t *usrp2_shorts,
+    size_t num_samps
+){
+    for(size_t i = 0; i < num_samps; i++){
+        host_shorts[i] = ntohs(usrp2_shorts[i]);
+    }
+}
+
+/***********************************************************************
+ * Send Raw Data
+ **********************************************************************/
+size_t usrp2_impl::send_raw(
+    const boost::asio::const_buffer &buff,
+    const uhd::metadata_t &metadata
+){
+    std::vector<boost::asio::const_buffer> buffs(2);
+    uint32_t vrt_hdr[max_vrt_header_words];
+    uint32_t vrt_hdr_flags = 0;
+    size_t num_vrt_hdr_words = 1;
+
+    //load the vrt header and flags
+    if(metadata.has_stream_id){
+        vrt_hdr_flags |= (0x1 << 28); //IF Data packet with Stream Identifier
+        vrt_hdr[num_vrt_hdr_words++] = htonl(metadata.stream_id);
+    }
+    if(metadata.has_time_spec){
+        vrt_hdr_flags |= (0x3 << 22) | (0x1 << 20); //TSI: Other, TSF: Sample Count Timestamp
+        vrt_hdr[num_vrt_hdr_words++] = htonl(metadata.time_spec.secs);
+        vrt_hdr[num_vrt_hdr_words++] = htonl(metadata.time_spec.ticks);
+        vrt_hdr[num_vrt_hdr_words++] = 0; //unused part of fractional seconds
+    }
+    vrt_hdr_flags |= (metadata.start_of_burst)? (0x1 << 25) : 0;
+    vrt_hdr_flags |= (metadata.end_of_burst)?   (0x1 << 24) : 0;
+
+    //fill in complete header word
+    vrt_hdr[0] = htonl(vrt_hdr_flags |
+        ((_stream_id_to_packet_seq[metadata.stream_id]++ << 16) & 0xf) |
+        ((boost::asio::buffer_size(buff)/sizeof(uint32_t)) & 0xffff)
+    );
+
+    //load the buffer vector
+    size_t vrt_hdr_size = num_vrt_hdr_words*sizeof(uint32_t);
+    buffs[0] = boost::asio::buffer(&vrt_hdr, vrt_hdr_size);
+    buffs[1] = buff;
+
+    //send and return number of samples
+    return (_data_transport->send(buffs) - vrt_hdr_size)/sizeof(sc16_t);
+}
+
+/***********************************************************************
+ * Receive Raw Data
+ **********************************************************************/
+size_t usrp2_impl::recv_raw(
+    const boost::asio::mutable_buffer &buff,
+    uhd::metadata_t &metadata
+){
+    //load the buffer vector
+    std::vector<boost::asio::mutable_buffer> buffs(2);
+    uint32_t vrt_hdr[max_vrt_header_words];
+    buffs[0] = boost::asio::buffer(vrt_hdr, max_vrt_header_words);
+    buffs[1] = buff;
+
+    //receive into the buffers
+    size_t bytes_recvd = _data_transport->recv(buffs);
+
+    //failure case
+    if (bytes_recvd < max_vrt_header_words*sizeof(uint32_t)) return 0;
+
+    //unpack the vrt header
+    metadata = uhd::metadata_t();
+    uint32_t vrt_header = ntohl(vrt_hdr[0]);
+    metadata.has_stream_id = true;
+    metadata.stream_id = ntohl(vrt_hdr[1]);
+    metadata.has_time_spec = true;
+    metadata.time_spec.secs = ntohl(vrt_hdr[2]);
+    metadata.time_spec.ticks = ntohl(vrt_hdr[3]);
+
+    //return the number of samples received
+    size_t num_words = vrt_header & 0xffff;
+    return (num_words*sizeof(uint32_t))/sizeof(sc16_t);
+}
+
+/***********************************************************************
+ * Send Data
+ **********************************************************************/
+size_t usrp2_impl::send(
+    const boost::asio::const_buffer &buff,
+    const uhd::metadata_t &metadata,
+    const std::string &type
+){
+    if (type == "fc32"){
+        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(fc32_t);
+        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
+        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
+
+        host_floats_to_usrp2_shorts(
+            boost::asio::buffer_cast<int16_t*>(raw_buff),
+            boost::asio::buffer_cast<const float*>(buff),
+            num_samps*2 //double for complex
+        );
+
+        return send_raw(raw_buff, metadata);
+    }
+
+    if (type == "sc16"){
+        #ifdef HAVE_BIG_ENDIAN
+        return send_raw(buff, metadata);
+        #else
+        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(sc16_t);
+        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
+        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
+
+        host_shorts_to_usrp2_shorts(
+            boost::asio::buffer_cast<int16_t*>(raw_buff),
+            boost::asio::buffer_cast<const int16_t*>(buff),
+            num_samps*2 //double for complex
+        );
+
+        return send_raw(raw_buff, metadata);
+        #endif
+    }
+
+    throw std::runtime_error(str(boost::format("usrp2 send: cannot handle type \"%s\"") % type));
+}
+
+/***********************************************************************
+ * Receive Data
+ **********************************************************************/
+size_t usrp2_impl::recv(
+    const boost::asio::mutable_buffer &buff,
+    uhd::metadata_t &metadata,
+    const std::string &type
+){
+    if (type == "fc32"){
+        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(fc32_t);
+        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
+        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
+
+        num_samps = recv_raw(raw_buff, metadata);
+
+        usrp2_shorts_to_host_floats(
+            boost::asio::buffer_cast<float*>(buff),
+            boost::asio::buffer_cast<const int16_t*>(raw_buff),
+            num_samps*2 //double for complex
+        );
+
+        return num_samps;
+    }
+
+    if (type == "sc16"){
+        #ifdef HAVE_BIG_ENDIAN
+        return recv_raw(buff, metadata);
+        #else
+        size_t num_samps = boost::asio::buffer_size(buff)/sizeof(sc16_t);
+        boost::shared_array<sc16_t> raw_mem(new sc16_t[num_samps]);
+        boost::asio::mutable_buffer raw_buff(raw_mem.get(), num_samps*sizeof(sc16_t));
+
+        num_samps = recv_raw(raw_buff, metadata);
+
+        usrp2_shorts_to_host_shorts(
+            boost::asio::buffer_cast<int16_t*>(buff),
+            boost::asio::buffer_cast<const int16_t*>(raw_buff),
+            num_samps*2 //double for complex
+        );
+
+        return num_samps;
+        #endif
+    }
+
+    throw std::runtime_error(str(boost::format("usrp2 recv: cannot handle type \"%s\"") % type));
+}
diff --git a/host/lib/usrp/usrp2/usrp2_impl.cpp b/host/lib/usrp/usrp2/usrp2_impl.cpp
index 47bf06aff..11e2f480b 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.cpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.cpp
@@ -44,19 +44,21 @@ uhd::device_addrs_t usrp2::discover(const device_addr_t &hint){
     //loop and recieve until the time is up
     size_t num_timeouts = 0;
     while(true){
-        uhd::shared_iovec iov = udp_transport->recv();
-        //std::cout << boost::asio::buffer_size(buff) << "\n";
-        if (iov.len < sizeof(usrp2_ctrl_data_t)){
+        usrp2_ctrl_data_t ctrl_data_in;
+        size_t len = udp_transport->recv(
+            boost::asio::buffer(&ctrl_data_in, sizeof(ctrl_data_in))
+        );
+        //std::cout << len << "\n";
+        if (len < sizeof(usrp2_ctrl_data_t)){
             //sleep a little so we dont burn cpu
             if (num_timeouts++ > 50) break;
             boost::this_thread::sleep(boost::posix_time::milliseconds(1));
         }else{
             //handle the received data
-            const usrp2_ctrl_data_t *ctrl_data_in = reinterpret_cast<const usrp2_ctrl_data_t *>(iov.base);
-            switch(ntohl(ctrl_data_in->id)){
+            switch(ntohl(ctrl_data_in.id)){
             case USRP2_CTRL_ID_THIS_IS_MY_IP_ADDR_DUDE:
                 //make a boost asio ipv4 with the raw addr in host byte order
-                boost::asio::ip::address_v4 ip_addr(ntohl(ctrl_data_in->data.ip_addr));
+                boost::asio::ip::address_v4 ip_addr(ntohl(ctrl_data_in.data.ip_addr));
                 device_addr_t new_addr;
                 new_addr["name"] = "USRP2";
                 new_addr["type"] = "udp";
@@ -161,14 +163,16 @@ usrp2_ctrl_data_t usrp2_impl::ctrl_send_and_recv(const usrp2_ctrl_data_t &out_da
     //loop and recieve until the time is up
     size_t num_timeouts = 0;
     while(true){
-        uhd::shared_iovec iov = _ctrl_transport->recv();
-        if (iov.len < sizeof(usrp2_ctrl_data_t)){
+        usrp2_ctrl_data_t in_data;
+        size_t len = _ctrl_transport->recv(
+            boost::asio::buffer(&in_data, sizeof(in_data))
+        );
+        if (len < sizeof(usrp2_ctrl_data_t)){
             //sleep a little so we dont burn cpu
             if (num_timeouts++ > 50) break;
             boost::this_thread::sleep(boost::posix_time::milliseconds(1));
         }else{
             //handle the received data
-            usrp2_ctrl_data_t in_data = *reinterpret_cast<const usrp2_ctrl_data_t *>(iov.base);
             if (ntohl(in_data.seq) == _ctrl_seq_num){
                 return in_data;
             }
@@ -204,76 +208,3 @@ void usrp2_impl::get(const wax::obj &key_, wax::obj &val){
 void usrp2_impl::set(const wax::obj &, const wax::obj &){
     throw std::runtime_error("Cannot set in usrp2 device");
 }
-
-/***********************************************************************
- * IO Interface
- **********************************************************************/
-static const float float_scale_factor = pow(2.0, 15);
-
-size_t usrp2_impl::send(
-    const boost::asio::const_buffer &buff,
-    const uhd::metadata_t &metadata,
-    const std::string &type
-){
-    if (type == "fc32"){
-        //extract the buffer elements
-        const float *float_buff = boost::asio::buffer_cast<const float*>(buff);
-        const size_t buff_len = boost::asio::buffer_size(buff)/sizeof(float);
-
-        //convert floats into the shorts buffer
-        int16_t *shorts_buff = new int16_t[buff_len];
-        for (size_t i = 0; i < buff_len; i++){
-            shorts_buff[i] = float_buff[i]*float_scale_factor;
-        }
-
-        //send from a buffer of shorts
-        size_t bytes_sent = send(
-            boost::asio::buffer(shorts_buff, buff_len*sizeof(int16_t)),
-            metadata, "sc16"
-        );
-
-        //cleanup
-        delete [] shorts_buff;
-        return bytes_sent;
-    }
-
-    if (type == "sc16"){
-        throw std::runtime_error("not implemented");
-    }
-
-    throw std::runtime_error(str(boost::format("usrp2 send: cannot handle type \"%s\"") % type));
-}
-
-size_t usrp2_impl::recv(
-    const boost::asio::mutable_buffer &buff,
-    uhd::metadata_t &metadata,
-    const std::string &type
-){
-    if (type == "fc32"){
-        //extract the buffer elements
-        float *float_buff = boost::asio::buffer_cast<float*>(buff);
-        const size_t buff_len = boost::asio::buffer_size(buff)/sizeof(float);
-
-        //receive into a buffer of shorts
-        int16_t *shorts_buff = new int16_t[buff_len];
-        size_t bytes_received = recv(
-            boost::asio::buffer(shorts_buff, buff_len*sizeof(int16_t)),
-            metadata, "sc16"
-        );
-
-        //convert floats into the shorts buffer
-        for (size_t i = 0; i < bytes_received/sizeof(int16_t); i++){
-            float_buff[i] = shorts_buff[i]/float_scale_factor;
-        }
-
-        //cleanup
-        delete [] shorts_buff;
-        return bytes_received;
-    }
-
-    if (type == "sc16"){
-        throw std::runtime_error("not implemented");
-    }
-
-    throw std::runtime_error(str(boost::format("usrp2 recv: cannot handle type \"%s\"") % type));
-}
diff --git a/host/lib/usrp/usrp2/usrp2_impl.hpp b/host/lib/usrp/usrp2/usrp2_impl.hpp
index 2476bcf1d..9a4c42d42 100644
--- a/host/lib/usrp/usrp2/usrp2_impl.hpp
+++ b/host/lib/usrp/usrp2/usrp2_impl.hpp
@@ -102,6 +102,11 @@ public:
     size_t recv(const boost::asio::mutable_buffer &, uhd::metadata_t &, const std::string &);
 
 private:
+    //the raw io interface (samples are in the usrp2 native format)
+    size_t send_raw(const boost::asio::const_buffer &, const uhd::metadata_t &);
+    size_t recv_raw(const boost::asio::mutable_buffer &, uhd::metadata_t &);
+    uhd::dict<uint32_t, size_t> _stream_id_to_packet_seq;
+
     //udp transports for control and data
     uhd::transport::udp::sptr _ctrl_transport;
     uhd::transport::udp::sptr _data_transport;