1 /////////////////////////////////////////////////////////////////////////
2 // $Id: mbuf.h 13932 2020-09-02 08:35:44Z vruppert $
3 /////////////////////////////////////////////////////////////////////////
4 /*
5 * Copyright (c) 1982, 1986, 1988, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)mbuf.h 8.3 (Berkeley) 1/21/94
33 * mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp
34 */
35
36 #ifndef _MBUF_H_
37 #define _MBUF_H_
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 /*
56 * How much room is in the mbuf, from m_data to the end of the mbuf
57 */
58 #define M_ROOM(m) ((m->m_flags & M_EXT)? \
59 (((m)->m_ext + (m)->m_size) - (m)->m_data) \
60 : \
61 (((m)->m_dat + (m)->m_size) - (m)->m_data))
62
63 /*
64 * How much free room there is
65 */
66 #define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
67 #define M_TRAILINGSPACE M_FREEROOM
68
69 struct mbuf {
70 /* XXX should union some of these! */
71 /* header at beginning of each mbuf: */
72 struct mbuf *m_next; /* Linked list of mbufs */
73 struct mbuf *m_prev;
74 struct mbuf *m_nextpkt; /* Next packet in queue/record */
75 struct mbuf *m_prevpkt; /* Flags aren't used in the output queue */
76 int m_flags; /* Misc flags */
77
78 int m_size; /* Size of data */
79 struct socket *m_so;
80
81 caddr_t m_data; /* Location of data */
82 int m_len; /* Amount of data in this mbuf */
83
84 Slirp *slirp;
85 bool arp_requested;
86 uint64_t expiration_date;
87 /* start of dynamic buffer area, must be last element */
88 union {
89 char m_dat[1]; /* ANSI don't like 0 sized arrays */
90 char *m_ext;
91 };
92 };
93
94 #define ifq_prev m_prev
95 #define ifq_next m_next
96 #define ifs_prev m_prevpkt
97 #define ifs_next m_nextpkt
98 #define ifq_so m_so
99
100 #define M_EXT 0x01 /* m_ext points to more (malloced) data */
101 #define M_FREELIST 0x02 /* mbuf is on free list */
102 #define M_USEDLIST 0x04 /* XXX mbuf is on used list (for dtom()) */
103 #define M_DOFREE 0x08 /* when m_free is called on the mbuf, free()
104 * it rather than putting it on the free list */
105
106 void m_init(Slirp *);
107 void m_cleanup(Slirp *slirp);
108 struct mbuf * m_get(Slirp *);
109 void m_free(struct mbuf *);
110 void m_cat(struct mbuf *, struct mbuf *);
111 void m_inc(struct mbuf *, int);
112 void m_adj(struct mbuf *, int);
113 int m_copy(struct mbuf *, struct mbuf *, int, int);
114 struct mbuf * dtom(Slirp *, void *);
115
ifs_init(struct mbuf * ifm)116 static inline void ifs_init(struct mbuf *ifm)
117 {
118 ifm->ifs_next = ifm->ifs_prev = ifm;
119 }
120
121 #endif
122