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/*
* Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* 3. Neither the name of the authors nor the names of their contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY MATTEO LANDI AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTEO LANDI OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* $FreeBSD$
* $Id: netmap_user.h 10597 2012-02-21 05:08:32Z luigi $
*
* This header contains the macros used to manipulate netmap structures
* and packets in userspace. See netmap(4) for more information.
*
* The address of the struct netmap_if, say nifp, is computed from the
* value returned from ioctl(.., NIOCREG, ...) and the mmap region:
* ioctl(fd, NIOCREG, &req);
* mem = mmap(0, ... );
* nifp = NETMAP_IF(mem, req.nr_nifp);
* (so simple, we could just do it manually)
*
* From there:
* struct netmap_ring *NETMAP_TXRING(nifp, index)
* struct netmap_ring *NETMAP_RXRING(nifp, index)
* we can access ring->nr_cur, ring->nr_avail, ring->nr_flags
*
* ring->slot[i] gives us the i-th slot (we can access
* directly plen, flags, bufindex)
*
* char *buf = NETMAP_BUF(ring, index) returns a pointer to
* the i-th buffer
*
* Since rings are circular, we have macros to compute the next index
* i = NETMAP_RING_NEXT(ring, i);
*/
#ifndef _NET_NETMAP_USER_H_
#define _NET_NETMAP_USER_H_
#define _NETMAP_OFFSET(type, ptr, offset) \
((type)(void *)((char *)(ptr) + (offset)))
#define NETMAP_IF(b, o) _NETMAP_OFFSET(struct netmap_if *, b, o)
#define NETMAP_TXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \
nifp, (nifp)->ring_ofs[index] )
#define NETMAP_RXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \
nifp, (nifp)->ring_ofs[index + (nifp)->ni_tx_rings + 1] )
#define NETMAP_BUF(ring, index) \
((char *)(ring) + (ring)->buf_ofs + ((index)*(ring)->nr_buf_size))
#define NETMAP_BUF_IDX(ring, buf) \
( ((char *)(buf) - ((char *)(ring) + (ring)->buf_ofs) ) / \
(ring)->nr_buf_size )
#define NETMAP_RING_NEXT(r, i) \
((i)+1 == (r)->num_slots ? 0 : (i) + 1 )
#define NETMAP_RING_FIRST_RESERVED(r) \
( (r)->cur < (r)->reserved ? \
(r)->cur + (r)->num_slots - (r)->reserved : \
(r)->cur - (r)->reserved )
/*
* Return 1 if the given tx ring is empty.
*/
#define NETMAP_TX_RING_EMPTY(r) ((r)->avail >= (r)->num_slots - 1)
#endif /* _NET_NETMAP_USER_H_ */
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