Annotation of qemu/slirp/mbuf.h, revision 1.1.1.3

1.1       root        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.
1.1.1.3 ! root       13:  * 3. Neither the name of the University nor the names of its contributors
1.1       root       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;
1.1.1.2   root       68: 
1.1       root       69:        caddr_t mh_data;                /* Location of data */
                     70:        int     mh_len;                 /* Amount of data in this mbuf */
                     71: };
                     72: 
1.1.1.2   root       73: /*
1.1       root       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 */
1.1.1.2   root      125: 
1.1       root      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

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