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: */ 59 struct 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 87 struct 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 */ 122 123 struct mbstat { 124 int mbs_alloced; /* Number of mbufs allocated */ 125 126 }; 127 128 extern struct mbstat mbstat; 129 extern int mbuf_alloced; 130 extern struct mbuf m_freelist, m_usedlist; 131 extern int mbuf_max; 132 133 void m_init _P((void)); 134 struct mbuf * m_get _P((void)); 135 void m_free _P((struct mbuf *)); 136 void m_cat _P((register struct mbuf *, register struct mbuf *)); 137 void m_inc _P((struct mbuf *, int)); 138 void m_adj _P((struct mbuf *, int)); 139 int m_copy _P((struct mbuf *, struct mbuf *, int, int)); 140 struct mbuf * dtom _P((void *)); 141 142 #endif 143
