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/* -*- c++ -*- */
/*
* Copyright 2008,2009 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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, or (at your option)
* any later version.
*
* GNU Radio 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef INCLUDED_VRT_SOCKET_RX_BUFFER_H
#define INCLUDED_VRT_SOCKET_RX_BUFFER_H
#include <boost/utility.hpp>
#include <vector>
#include <memory>
#include <stdint.h>
namespace vrt {
class data_handler;
/*!
* \brief high-performance interface to receive datagrams
*
* On many systems it should be possible to implement this on top of libpcap
*
* \internal
*/
class socket_rx_buffer : boost::noncopyable
{
int d_fd; // socket file descriptor
bool d_using_tpring; // using kernel mapped packet ring
size_t d_buflen; // length of our buffer
uint8_t *d_buf; // packet ring
unsigned int d_frame_nr; // max frames on ring
size_t d_frame_size; // frame storage size
unsigned int d_head; // pointer to next frame
std::vector<uint8_t *> d_ring; // pointers into buffer
bool frame_available();
void inc_head()
{
if (d_head + 1 >= d_frame_nr)
d_head = 0;
else
d_head = d_head + 1;
}
bool open();
bool close();
bool try_packet_ring();
public:
enum result {
EB_OK, //< everything's fine
EB_ERROR, //< A non-recoverable error occurred
EB_WOULD_BLOCK, //< A timeout of 0 was specified and nothing was ready
EB_TIMED_OUT, //< The timeout expired before anything was ready
};
static const unsigned int MAX_PKTLEN;
static const unsigned int MIN_PKTLEN;
/*!
* \param socket_fd file descriptor that corresponds to a socket
* \param rx_bufsize is a hint as to the number of bytes of memory
* to allocate for received ethernet frames (0 -> reasonable default)
*/
socket_rx_buffer(int socket_fd, size_t rx_bufsize = 0);
~socket_rx_buffer();
/*!
* \brief Call \p f for each frame in the receive buffer.
* \param f is the frame data handler
* \param timeout (in ms) controls behavior when there are no frames to read
*
* If \p timeout is 0, rx_frames will not wait for frames if none are
* available, and f will not be invoked. If \p timeout is -1 (the
* default), rx_frames will block indefinitely until frames are
* available. If \p timeout is positive, it indicates the number of
* milliseconds to wait for a frame to become available. Once the
* timeout has expired, rx_frames will return, f never having been
* invoked.
*
* \p f will be called on each frame that is available.
* \p f returns a bit mask with one of the following set or cleared:
*
* data_handler::DONE - return from rx_frames now even though more frames
* might be available; otherwise continue if more
* frames are ready.
*
* \returns EB_OK if at least one frame was received
* \returns EB_WOULD_BLOCK if \p timeout is 0 and the call would have blocked
* \returns EB_TIMED_OUT if timeout occurred
* \returns EB_ERROR if there was an unrecoverable error.
*/
result rx_frames(data_handler *f, int timeout=-1);
/*
* \brief Returns maximum possible number of frames in buffer
*/
unsigned int max_frames() const { return d_using_tpring ? d_frame_nr : 0; }
};
}; // namespace vrt
#endif /* INCLUDED_VRT_SOCKET_RX_BUFFER_H */
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