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