/* -*- c++ -*- */ /* * Copyright 2008 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_USRP2_ETH_BUFFER_H #define INCLUDED_USRP2_ETH_BUFFER_H #include "pktfilter.h" #include #include #include #include #include namespace usrp2 { class ethernet; class data_handler; /*! * \brief high-performance interface to send and receive raw * ethernet frames with out-of-order retirement of received frames. * * On many systems it should be possible to implement this on top of libpcap * * \internal */ class eth_buffer : boost::noncopyable { int d_fd; // socket file descriptor uint8_t d_mac[6]; // our mac address 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 d_ring; // pointers into buffer std::auto_ptr d_ethernet; // our underlying interface bool frame_available(); void inc_head() { if (d_head + 1 >= d_frame_nr) d_head = 0; else d_head = d_head + 1; } 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 = 1512; static const unsigned int MIN_PKTLEN = 64; /*! * \param rx_bufsize is a hint as to the number of bytes of memory * to allocate for received ethernet frames (0 -> reasonable default) */ eth_buffer(size_t rx_bufsize = 0); ~eth_buffer(); /*! * \brief open the specified interface * * \param ifname ethernet interface name, e.g., "eth0" * \param protocol is the ethertype protocol number in network order. * Use 0 to receive all protocols. */ bool open(const std::string &ifname, int protocol); /*! * \brief close the interface */ bool close(); /*! * \brief attach packet filter to socket to restrict which packets read sees. * \param pf the packet filter */ bool attach_pktfilter(pktfilter *pf); /*! * \brief return 6 byte string containing our MAC address */ const uint8_t *mac() const { return d_mac; } /*! * \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 ethernet frame that is available. * \p f returns a bit mask with one of the following set or cleared: * * data_handler::KEEP - hold onto the frame and present it again during * the next call to rx_frames, otherwise discard it * * data_handler::DONE - return from rx_frames now even though more frames * might be available; otherwise continue if more * frames are ready. * * The idea of holding onto a frame for the next iteration allows * the caller to scan the received packet stream for particular * classes of frames (such as command replies) leaving the rest * intact. On the next call all kept frames, followed by any new * frames received, will be presented in order to \p f. * See usrp2.cc for an example of the pattern. * * \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 Release frame from buffer * * Call to release a frame previously held by a data_handler::KEEP. * The pointer may be offset from the base of the frame up to its length. */ void release_frame(void *p); /* * \brief Write an ethernet frame to the interface. * * \param base points to the beginning of the frame (the 14-byte ethernet header). * \param len is the length of the frame in bytes. * \param flags is 0 or the bitwise-or of values from eth_flags * * The frame must begin with a 14-byte ethernet header. * * \returns EB_OK if the frame was successfully enqueued. * \returns EB_WOULD_BLOCK if flags contains EF_DONT_WAIT and the call would have blocked. * \returns EB_ERROR if there was an unrecoverable error. */ result tx_frame(const void *base, size_t len, int flags=0); /* * \brief Write an ethernet frame to the interface using scatter/gather. * * \param iov points to an array of iovec structs * \param iovcnt is the number of entries * \param flags is 0 or the bitwise-or of values from eth_flags * * The frame must begin with a 14-byte ethernet header. * * \returns EB_OK if the frame was successfully enqueued. * \returns EB_WOULD_BLOCK if flags contains EF_DONT_WAIT and the call would have blocked. * \returns EB_ERROR if there was an unrecoverable error. */ result tx_framev(const eth_iovec *iov, int iovcnt, int flags=0); /* * \brief Returns maximum possible number of frames in buffer */ unsigned int max_frames() const { return d_frame_nr; } }; }; // namespace usrp2 #endif /* INCLUDED_USRP2_ETH_BUFFER_H */