File:  [Qemu by Fabrice Bellard] / qemu / slirp / mbuf.h
Revision 1.1.1.4 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 17:25:34 2018 UTC (2 years, 11 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu0150, qemu0141, qemu0140, qemu0130, qemu0125, qemu0124, qemu0123, qemu0122, qemu0121, qemu0120, qemu0111, qemu0110, HEAD
qemu 0.11.0

    1: /*
    2:  * Copyright (c) 1982, 1986, 1988, 1993
    3:  *	The Regents of the University of California.  All rights reserved.
    4:  *
    5:  * Redistribution and use in source and binary forms, with or without
    6:  * modification, are permitted provided that the following conditions
    7:  * are met:
    8:  * 1. Redistributions of source code must retain the above copyright
    9:  *    notice, this list of conditions and the following disclaimer.
   10:  * 2. Redistributions in binary form must reproduce the above copyright
   11:  *    notice, this list of conditions and the following disclaimer in the
   12:  *    documentation and/or other materials provided with the distribution.
   13:  * 3. Neither the name of the University nor the names of its contributors
   14:  *    may be used to endorse or promote products derived from this software
   15:  *    without specific prior written permission.
   16:  *
   17:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27:  * SUCH DAMAGE.
   28:  *
   29:  *	@(#)mbuf.h	8.3 (Berkeley) 1/21/94
   30:  * mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp
   31:  */
   32: 
   33: #ifndef _MBUF_H_
   34: #define _MBUF_H_
   35: 
   36: #define m_freem m_free
   37: 
   38: 
   39: #define MINCSIZE 4096	/* Amount to increase mbuf if too small */
   40: 
   41: /*
   42:  * Macros for type conversion
   43:  * mtod(m,t) -	convert mbuf pointer to data pointer of correct type
   44:  */
   45: #define mtod(m,t)	((t)(m)->m_data)
   46: 
   47: /* XXX About mbufs for slirp:
   48:  * Only one mbuf is ever used in a chain, for each "cell" of data.
   49:  * m_nextpkt points to the next packet, if fragmented.
   50:  * If the data is too large, the M_EXT is used, and a larger block
   51:  * is alloced.  Therefore, m_free[m] must check for M_EXT and if set
   52:  * free the m_ext.  This is inefficient memory-wise, but who cares.
   53:  */
   54: 
   55: /* XXX should union some of these! */
   56: /* header at beginning of each mbuf: */
   57: struct m_hdr {
   58: 	struct	mbuf *mh_next;		/* Linked list of mbufs */
   59: 	struct	mbuf *mh_prev;
   60: 	struct	mbuf *mh_nextpkt;	/* Next packet in queue/record */
   61: 	struct	mbuf *mh_prevpkt; /* Flags aren't used in the output queue */
   62: 	int	mh_flags;	  /* Misc flags */
   63: 
   64: 	int	mh_size;		/* Size of data */
   65: 	struct	socket *mh_so;
   66: 
   67: 	caddr_t	mh_data;		/* Location of data */
   68: 	int	mh_len;			/* Amount of data in this mbuf */
   69: };
   70: 
   71: /*
   72:  * How much room is in the mbuf, from m_data to the end of the mbuf
   73:  */
   74: #define M_ROOM(m) ((m->m_flags & M_EXT)? \
   75: 			(((m)->m_ext + (m)->m_size) - (m)->m_data) \
   76: 		   : \
   77: 			(((m)->m_dat + (m)->m_size) - (m)->m_data))
   78: 
   79: /*
   80:  * How much free room there is
   81:  */
   82: #define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
   83: #define M_TRAILINGSPACE M_FREEROOM
   84: 
   85: struct mbuf {
   86: 	struct	m_hdr m_hdr;
   87: 	Slirp *slirp;
   88: 	union M_dat {
   89: 		char	m_dat_[1]; /* ANSI don't like 0 sized arrays */
   90: 		char	*m_ext_;
   91: 	} M_dat;
   92: };
   93: 
   94: #define m_next		m_hdr.mh_next
   95: #define m_prev		m_hdr.mh_prev
   96: #define m_nextpkt	m_hdr.mh_nextpkt
   97: #define m_prevpkt	m_hdr.mh_prevpkt
   98: #define m_flags		m_hdr.mh_flags
   99: #define	m_len		m_hdr.mh_len
  100: #define	m_data		m_hdr.mh_data
  101: #define m_size		m_hdr.mh_size
  102: #define m_dat		M_dat.m_dat_
  103: #define m_ext		M_dat.m_ext_
  104: #define m_so		m_hdr.mh_so
  105: 
  106: #define ifq_prev m_prev
  107: #define ifq_next m_next
  108: #define ifs_prev m_prevpkt
  109: #define ifs_next m_nextpkt
  110: #define ifq_so m_so
  111: 
  112: #define M_EXT			0x01	/* m_ext points to more (malloced) data */
  113: #define M_FREELIST		0x02	/* mbuf is on free list */
  114: #define M_USEDLIST		0x04	/* XXX mbuf is on used list (for dtom()) */
  115: #define M_DOFREE		0x08	/* when m_free is called on the mbuf, free()
  116: 					 * it rather than putting it on the free list */
  117: 
  118: void m_init(Slirp *);
  119: struct mbuf * m_get(Slirp *);
  120: void m_free(struct mbuf *);
  121: void m_cat(register struct mbuf *, register struct mbuf *);
  122: void m_inc(struct mbuf *, int);
  123: void m_adj(struct mbuf *, int);
  124: int m_copy(struct mbuf *, struct mbuf *, int, int);
  125: struct mbuf * dtom(Slirp *, void *);
  126: 
  127: #endif

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