File:  [Qemu by Fabrice Bellard] / qemu / slirp / mbuf.h
Revision 1.1.1.5 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 19:02:40 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu1000, qemu0151, HEAD
qemu 0.15.1

    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 MINCSIZE 4096	/* Amount to increase mbuf if too small */
   37: 
   38: /*
   39:  * Macros for type conversion
   40:  * mtod(m,t) -	convert mbuf pointer to data pointer of correct type
   41:  */
   42: #define mtod(m,t)	((t)(m)->m_data)
   43: 
   44: /* XXX About mbufs for slirp:
   45:  * Only one mbuf is ever used in a chain, for each "cell" of data.
   46:  * m_nextpkt points to the next packet, if fragmented.
   47:  * If the data is too large, the M_EXT is used, and a larger block
   48:  * is alloced.  Therefore, m_free[m] must check for M_EXT and if set
   49:  * free the m_ext.  This is inefficient memory-wise, but who cares.
   50:  */
   51: 
   52: /* XXX should union some of these! */
   53: /* header at beginning of each mbuf: */
   54: struct m_hdr {
   55: 	struct	mbuf *mh_next;		/* Linked list of mbufs */
   56: 	struct	mbuf *mh_prev;
   57: 	struct	mbuf *mh_nextpkt;	/* Next packet in queue/record */
   58: 	struct	mbuf *mh_prevpkt; /* Flags aren't used in the output queue */
   59: 	int	mh_flags;	  /* Misc flags */
   60: 
   61: 	int	mh_size;		/* Size of data */
   62: 	struct	socket *mh_so;
   63: 
   64: 	caddr_t	mh_data;		/* Location of data */
   65: 	int	mh_len;			/* Amount of data in this mbuf */
   66: };
   67: 
   68: /*
   69:  * How much room is in the mbuf, from m_data to the end of the mbuf
   70:  */
   71: #define M_ROOM(m) ((m->m_flags & M_EXT)? \
   72: 			(((m)->m_ext + (m)->m_size) - (m)->m_data) \
   73: 		   : \
   74: 			(((m)->m_dat + (m)->m_size) - (m)->m_data))
   75: 
   76: /*
   77:  * How much free room there is
   78:  */
   79: #define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
   80: #define M_TRAILINGSPACE M_FREEROOM
   81: 
   82: struct mbuf {
   83: 	struct	m_hdr m_hdr;
   84: 	Slirp *slirp;
   85: 	union M_dat {
   86: 		char	m_dat_[1]; /* ANSI don't like 0 sized arrays */
   87: 		char	*m_ext_;
   88: 	} M_dat;
   89: };
   90: 
   91: #define m_next		m_hdr.mh_next
   92: #define m_prev		m_hdr.mh_prev
   93: #define m_nextpkt	m_hdr.mh_nextpkt
   94: #define m_prevpkt	m_hdr.mh_prevpkt
   95: #define m_flags		m_hdr.mh_flags
   96: #define	m_len		m_hdr.mh_len
   97: #define	m_data		m_hdr.mh_data
   98: #define m_size		m_hdr.mh_size
   99: #define m_dat		M_dat.m_dat_
  100: #define m_ext		M_dat.m_ext_
  101: #define m_so		m_hdr.mh_so
  102: 
  103: #define ifq_prev m_prev
  104: #define ifq_next m_next
  105: #define ifs_prev m_prevpkt
  106: #define ifs_next m_nextpkt
  107: #define ifq_so m_so
  108: 
  109: #define M_EXT			0x01	/* m_ext points to more (malloced) data */
  110: #define M_FREELIST		0x02	/* mbuf is on free list */
  111: #define M_USEDLIST		0x04	/* XXX mbuf is on used list (for dtom()) */
  112: #define M_DOFREE		0x08	/* when m_free is called on the mbuf, free()
  113: 					 * it rather than putting it on the free list */
  114: 
  115: void m_init(Slirp *);
  116: struct mbuf * m_get(Slirp *);
  117: void m_free(struct mbuf *);
  118: void m_cat(register struct mbuf *, register struct mbuf *);
  119: void m_inc(struct mbuf *, int);
  120: void m_adj(struct mbuf *, int);
  121: int m_copy(struct mbuf *, struct mbuf *, int, int);
  122: struct mbuf * dtom(Slirp *, void *);
  123: 
  124: #endif

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