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//
// Copyright 2010-2014 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//
#include "udp_common.hpp"
#include <uhd/transport/tcp_zero_copy.hpp>
#include <uhd/transport/buffer_pool.hpp>
#include <uhd/utils/log.hpp>
#include <uhdlib/utils/atomic.hpp>
#include <boost/format.hpp>
#include <boost/make_shared.hpp>
#include <boost/thread/thread.hpp> //sleep
#include <vector>
using namespace uhd;
using namespace uhd::transport;
namespace asio = boost::asio;
static const size_t DEFAULT_NUM_FRAMES = 32;
static const size_t DEFAULT_FRAME_SIZE = 2048;
/***********************************************************************
* Reusable managed receiver buffer:
* - get_new performs the recv operation
**********************************************************************/
class tcp_zero_copy_asio_mrb : public managed_recv_buffer{
public:
tcp_zero_copy_asio_mrb(void *mem, int sock_fd, const size_t frame_size):
_mem(mem), _sock_fd(sock_fd), _frame_size(frame_size) { /*NOP*/ }
void release(void){
_claimer.release();
}
UHD_INLINE sptr get_new(const double timeout, size_t &index){
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
if (wait_for_recv_ready(_sock_fd, timeout)){
_len = ::recv(_sock_fd, (char *)_mem, _frame_size, 0);
index++; //advances the caller's buffer
return make(this, _mem, size_t(_len));
}
_claimer.release(); //undo claim
return sptr(); //null for timeout
}
private:
void *_mem;
int _sock_fd;
size_t _frame_size;
ssize_t _len;
simple_claimer _claimer;
};
/***********************************************************************
* Reusable managed send buffer:
* - commit performs the send operation
**********************************************************************/
class tcp_zero_copy_asio_msb : public managed_send_buffer{
public:
tcp_zero_copy_asio_msb(void *mem, int sock_fd, const size_t frame_size):
_mem(mem), _sock_fd(sock_fd), _frame_size(frame_size) { /*NOP*/ }
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)
{
this->commit(_frame_size); //always full size frames to avoid pkt coalescing
const ssize_t ret = ::send(_sock_fd, (const char *)_mem, size(), 0);
if (ret == ssize_t(size())) break;
if (ret == -1 and errno == ENOBUFS)
{
boost::this_thread::sleep(boost::posix_time::microseconds(1));
continue; //try to send again
}
UHD_ASSERT_THROW(ret == ssize_t(size()));
}
_claimer.release();
}
UHD_INLINE sptr get_new(const double timeout, size_t &index){
if (not _claimer.claim_with_wait(timeout)) return sptr();
index++; //advances the caller's buffer
return make(this, _mem, _frame_size);
}
private:
void *_mem;
int _sock_fd;
size_t _frame_size;
simple_claimer _claimer;
};
tcp_zero_copy::~tcp_zero_copy(void){
/* NOP */
}
/***********************************************************************
* Zero Copy TCP implementation with ASIO:
* This is the portable zero copy implementation for systems
* where a faster, platform specific solution is not available.
* However, it is not a true zero copy implementation as each
* send and recv requires a copy operation to/from userspace.
**********************************************************************/
class tcp_zero_copy_asio_impl : public tcp_zero_copy{
public:
typedef boost::shared_ptr<tcp_zero_copy_asio_impl> sptr;
tcp_zero_copy_asio_impl(
const std::string &addr,
const std::string &port,
const device_addr_t &hints
):
_recv_frame_size(size_t(hints.cast<double>("recv_frame_size", DEFAULT_FRAME_SIZE))),
_num_recv_frames(size_t(hints.cast<double>("num_recv_frames", DEFAULT_NUM_FRAMES))),
_send_frame_size(size_t(hints.cast<double>("send_frame_size", DEFAULT_FRAME_SIZE))),
_num_send_frames(size_t(hints.cast<double>("num_send_frames", DEFAULT_NUM_FRAMES))),
_recv_buffer_pool(buffer_pool::make(_num_recv_frames, _recv_frame_size)),
_send_buffer_pool(buffer_pool::make(_num_send_frames, _send_frame_size)),
_next_recv_buff_index(0), _next_send_buff_index(0)
{
UHD_LOGGER_TRACE("TCP") << boost::format("Creating tcp transport for %s %s") % addr % port ;
//resolve the address
asio::ip::tcp::resolver resolver(_io_service);
asio::ip::tcp::resolver::query query(asio::ip::tcp::v4(), addr, port);
asio::ip::tcp::endpoint receiver_endpoint = *resolver.resolve(query);
//create, open, and connect the socket
_socket.reset(new asio::ip::tcp::socket(_io_service));
_socket->connect(receiver_endpoint);
_sock_fd = _socket->native_handle();
//packets go out ASAP
asio::ip::tcp::no_delay option(true);
_socket->set_option(option);
//allocate re-usable managed receive buffers
for (size_t i = 0; i < get_num_recv_frames(); i++){
_mrb_pool.push_back(boost::make_shared<tcp_zero_copy_asio_mrb>(
_recv_buffer_pool->at(i), _sock_fd, get_recv_frame_size()
));
}
//allocate re-usable managed send buffers
for (size_t i = 0; i < get_num_send_frames(); i++){
_msb_pool.push_back(boost::make_shared<tcp_zero_copy_asio_msb>(
_send_buffer_pool->at(i), _sock_fd, get_send_frame_size()
));
}
}
/*******************************************************************
* Receive implementation:
* Block on the managed buffer's get call and advance the index.
******************************************************************/
managed_recv_buffer::sptr get_recv_buff(double timeout){
if (_next_recv_buff_index == _num_recv_frames) _next_recv_buff_index = 0;
return _mrb_pool[_next_recv_buff_index]->get_new(timeout, _next_recv_buff_index);
}
size_t get_num_recv_frames(void) const {return _num_recv_frames;}
size_t get_recv_frame_size(void) const {return _recv_frame_size;}
/*******************************************************************
* Send implementation:
* Block on the managed buffer's get call and advance the index.
******************************************************************/
managed_send_buffer::sptr get_send_buff(double timeout){
if (_next_send_buff_index == _num_send_frames) _next_send_buff_index = 0;
return _msb_pool[_next_send_buff_index]->get_new(timeout, _next_send_buff_index);
}
size_t get_num_send_frames(void) const {return _num_send_frames;}
size_t get_send_frame_size(void) const {return _send_frame_size;}
private:
//memory management -> buffers and fifos
const size_t _recv_frame_size, _num_recv_frames;
const size_t _send_frame_size, _num_send_frames;
buffer_pool::sptr _recv_buffer_pool, _send_buffer_pool;
std::vector<boost::shared_ptr<tcp_zero_copy_asio_msb> > _msb_pool;
std::vector<boost::shared_ptr<tcp_zero_copy_asio_mrb> > _mrb_pool;
size_t _next_recv_buff_index, _next_send_buff_index;
//asio guts -> socket and service
asio::io_service _io_service;
boost::shared_ptr<asio::ip::tcp::socket> _socket;
int _sock_fd;
};
/***********************************************************************
* TCP zero copy make function
**********************************************************************/
zero_copy_if::sptr tcp_zero_copy::make(
const std::string &addr,
const std::string &port,
const device_addr_t &hints
){
zero_copy_if::sptr xport;
xport.reset(new tcp_zero_copy_asio_impl(addr, port, hints));
while (xport->get_recv_buff(0.0)){} //flush
return xport;
}
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