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 * dtom(x) -	convert data pointer within mbuf to mbuf pointer (XXX)
45 */
46#define mtod(m,t)	((t)(m)->m_data)
47/* #define	dtom(x)		((struct mbuf *)((int)(x) & ~(M_SIZE-1))) */
48
49/* XXX About mbufs for slirp:
50 * Only one mbuf is ever used in a chain, for each "cell" of data.
51 * m_nextpkt points to the next packet, if fragmented.
52 * If the data is too large, the M_EXT is used, and a larger block
53 * is alloced.  Therefore, m_free[m] must check for M_EXT and if set
54 * free the m_ext.  This is inefficient memory-wise, but who cares.
55 */
56
57/* XXX should union some of these! */
58/* header at beginning of each mbuf: */
59struct m_hdr {
60	struct	mbuf *mh_next;		/* Linked list of mbufs */
61	struct	mbuf *mh_prev;
62	struct	mbuf *mh_nextpkt;	/* Next packet in queue/record */
63	struct	mbuf *mh_prevpkt; /* Flags aren't used in the output queue */
64	int	mh_flags;	  /* Misc flags */
65
66	int	mh_size;		/* Size of data */
67	struct	socket *mh_so;
68
69	caddr_t	mh_data;		/* Location of data */
70	int	mh_len;			/* Amount of data in this mbuf */
71};
72
73/*
74 * How much room is in the mbuf, from m_data to the end of the mbuf
75 */
76#define M_ROOM(m) ((m->m_flags & M_EXT)? \
77			(((m)->m_ext + (m)->m_size) - (m)->m_data) \
78		   : \
79			(((m)->m_dat + (m)->m_size) - (m)->m_data))
80
81/*
82 * How much free room there is
83 */
84#define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
85#define M_TRAILINGSPACE M_FREEROOM
86
87struct mbuf {
88	struct	m_hdr m_hdr;
89	union M_dat {
90		char	m_dat_[1]; /* ANSI don't like 0 sized arrays */
91		char	*m_ext_;
92	} M_dat;
93};
94
95#define m_next		m_hdr.mh_next
96#define m_prev		m_hdr.mh_prev
97#define m_nextpkt	m_hdr.mh_nextpkt
98#define m_prevpkt	m_hdr.mh_prevpkt
99#define m_flags		m_hdr.mh_flags
100#define	m_len		m_hdr.mh_len
101#define	m_data		m_hdr.mh_data
102#define m_size		m_hdr.mh_size
103#define m_dat		M_dat.m_dat_
104#define m_ext		M_dat.m_ext_
105#define m_so		m_hdr.mh_so
106
107#define ifq_prev m_prev
108#define ifq_next m_next
109#define ifs_prev m_prevpkt
110#define ifs_next m_nextpkt
111#define ifq_so m_so
112
113#define M_EXT			0x01	/* m_ext points to more (malloced) data */
114#define M_FREELIST		0x02	/* mbuf is on free list */
115#define M_USEDLIST		0x04	/* XXX mbuf is on used list (for dtom()) */
116#define M_DOFREE		0x08	/* when m_free is called on the mbuf, free()
117					 * it rather than putting it on the free list */
118
119/*
120 * Mbuf statistics. XXX
121 */
122
123struct mbstat {
124	int mbs_alloced;		/* Number of mbufs allocated */
125
126};
127
128extern struct	mbstat mbstat;
129extern int mbuf_alloced;
130extern struct mbuf m_freelist, m_usedlist;
131extern int mbuf_max;
132
133void m_init _P((void));
134struct mbuf * m_get _P((void));
135void m_free _P((struct mbuf *));
136void m_cat _P((register struct mbuf *, register struct mbuf *));
137void m_inc _P((struct mbuf *, int));
138void m_adj _P((struct mbuf *, int));
139int m_copy _P((struct mbuf *, struct mbuf *, int, int));
140struct mbuf * dtom _P((void *));
141
142#endif
143