Annotation of kernel/bsd/sys/mbuf.h, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
                      3:  *
                      4:  * @APPLE_LICENSE_HEADER_START@
                      5:  * 
                      6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
                      7:  * Reserved.  This file contains Original Code and/or Modifications of
                      8:  * Original Code as defined in and that are subject to the Apple Public
                      9:  * Source License Version 1.1 (the "License").  You may not use this file
                     10:  * except in compliance with the License.  Please obtain a copy of the
                     11:  * License at http://www.apple.com/publicsource and read it before using
                     12:  * this file.
                     13:  * 
                     14:  * The Original Code and all software distributed under the License are
                     15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
                     16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
                     17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
                     18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
                     19:  * License for the specific language governing rights and limitations
                     20:  * under the License.
                     21:  * 
                     22:  * @APPLE_LICENSE_HEADER_END@
                     23:  */
                     24: 
                     25: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
                     26: /*
                     27:  * Copyright (c) 1982, 1986, 1988, 1993
                     28:  *     The Regents of the University of California.  All rights reserved.
                     29:  *
                     30:  * Redistribution and use in source and binary forms, with or without
                     31:  * modification, are permitted provided that the following conditions
                     32:  * are met:
                     33:  * 1. Redistributions of source code must retain the above copyright
                     34:  *    notice, this list of conditions and the following disclaimer.
                     35:  * 2. Redistributions in binary form must reproduce the above copyright
                     36:  *    notice, this list of conditions and the following disclaimer in the
                     37:  *    documentation and/or other materials provided with the distribution.
                     38:  * 3. All advertising materials mentioning features or use of this software
                     39:  *    must display the following acknowledgement:
                     40:  *     This product includes software developed by the University of
                     41:  *     California, Berkeley and its contributors.
                     42:  * 4. Neither the name of the University nor the names of its contributors
                     43:  *    may be used to endorse or promote products derived from this software
                     44:  *    without specific prior written permission.
                     45:  *
                     46:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     47:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     48:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     49:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     50:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     51:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     52:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     53:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     54:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     55:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     56:  * SUCH DAMAGE.
                     57:  *
                     58:  *     @(#)mbuf.h      8.5 (Berkeley) 2/19/95
                     59:  */
                     60: 
                     61: #ifndef        _SYS_MBUF_H_
                     62: #define        _SYS_MBUF_H_
                     63: 
                     64: /*
                     65:  * Mbufs are of a single size, MSIZE (machine/param.h), which
                     66:  * includes overhead.  An mbuf may add a single "mbuf cluster" of size
                     67:  * MCLBYTES (also in machine/param.h), which has no additional overhead
                     68:  * and is used instead of the internal data area; this is done when
                     69:  * at least MINCLSIZE of data must be stored.
                     70:  */
                     71: 
                     72: #define        MLEN            (MSIZE - sizeof(struct m_hdr))  /* normal data len */
                     73: #define        MHLEN           (MLEN - sizeof(struct pkthdr))  /* data len w/pkthdr */
                     74: 
                     75: #define        MINCLSIZE       (MHLEN + MLEN)  /* smallest amount to put in cluster */
                     76: #define        M_MAXCOMPRESS   (MHLEN / 2)     /* max amount to copy for compression */
                     77: 
                     78: #define NMBPCL         (sizeof(union mcluster) / sizeof(struct mbuf))
                     79: 
                     80: 
                     81: /*
                     82:  * Macros for type conversion
                     83:  * mtod(m,t) - convert mbuf pointer to data pointer of correct type
                     84:  * dtom(x) -   convert data pointer within mbuf to mbuf pointer (XXX)
                     85:  * mtocl(x) -  convert pointer within cluster to cluster index #
                     86:  * cltom(x) -  convert cluster # to ptr to beginning of cluster
                     87:  */
                     88: #define mtod(m,t)      ((t)((m)->m_data))
                     89: #define        dtom(x)         ((struct mbuf *)((u_long)(x) & ~(MSIZE-1)))
                     90: #define        mtocl(x)        ((union mcluster *)(x) - (union mcluster *)mbutl)
                     91: #define        cltom(x)        ((union mcluster *)(mbutl + (x)))
                     92: 
                     93: #define MCLREF(p)      (++mclrefcnt[mtocl(p)])
                     94: #define MCLUNREF(p)    (--mclrefcnt[mtocl(p)] == 0)
                     95: 
                     96: /* header at beginning of each mbuf: */
                     97: struct m_hdr {
                     98:        struct  mbuf *mh_next;          /* next buffer in chain */
                     99:        struct  mbuf *mh_nextpkt;       /* next chain in queue/record */
                    100:        long    mh_len;                 /* amount of data in this mbuf */
                    101:        caddr_t mh_data;                /* location of data */
                    102:        short   mh_type;                /* type of data in this mbuf */
                    103:        short   mh_flags;               /* flags; see below */
                    104: };
                    105: 
                    106: /* record/packet header in first mbuf of chain; valid if M_PKTHDR set */
                    107: struct pkthdr {
                    108:        int     len;                    /* total packet length */
                    109:        struct  ifnet *rcvif;           /* rcv interface */
                    110: };
                    111: 
                    112: 
                    113: /* description of external storage mapped into mbuf, valid if M_EXT set */
                    114: struct m_ext {
                    115:        caddr_t ext_buf;                /* start of buffer */
                    116:        void    (*ext_free)();          /* free routine if not the usual */
                    117:        u_int   ext_size;               /* size of buffer, for ext_free */
                    118:        caddr_t ext_arg;                /* additional ext_free argument */
                    119:        struct  ext_refsq {             /* references held */
                    120:                struct ext_refsq *forward, *backward;
                    121:        } ext_refs;
                    122: };
                    123: 
                    124: struct mbuf {
                    125:        struct  m_hdr m_hdr;
                    126:        union {
                    127:                struct {
                    128:                        struct  pkthdr MH_pkthdr;       /* M_PKTHDR set */
                    129:                        union {
                    130:                                struct  m_ext MH_ext;   /* M_EXT set */
                    131:                                char    MH_databuf[MHLEN];
                    132:                        } MH_dat;
                    133:                } MH;
                    134:                char    M_databuf[MLEN];                /* !M_PKTHDR, !M_EXT */
                    135:        } M_dat;
                    136: };
                    137: 
                    138: #define        m_next          m_hdr.mh_next
                    139: #define        m_len           m_hdr.mh_len
                    140: #define        m_data          m_hdr.mh_data
                    141: #define        m_type          m_hdr.mh_type
                    142: #define        m_flags         m_hdr.mh_flags
                    143: #define        m_nextpkt       m_hdr.mh_nextpkt
                    144: #define        m_act           m_nextpkt
                    145: #define        m_pkthdr        M_dat.MH.MH_pkthdr
                    146: #define        m_ext           M_dat.MH.MH_dat.MH_ext
                    147: #define        m_pktdat        M_dat.MH.MH_dat.MH_databuf
                    148: #define        m_dat           M_dat.M_databuf
                    149: 
                    150: /* mbuf flags */
                    151: #define        M_EXT           0x0001  /* has associated external storage */
                    152: #define        M_PKTHDR        0x0002  /* start of record */
                    153: #define        M_EOR           0x0004  /* end of record */
                    154: 
                    155: /* mbuf pkthdr flags, also in m_flags */
                    156: #define        M_BCAST         0x0100  /* send/received as link-level broadcast */
                    157: #define        M_MCAST         0x0200  /* send/received as link-level multicast */
                    158: 
                    159: /* flags copied when copying m_pkthdr */
                    160: #define        M_COPYFLAGS     (M_PKTHDR|M_EOR|M_BCAST|M_MCAST)
                    161: 
                    162: /* mbuf types */
                    163: #define        MT_FREE         0       /* should be on free list */
                    164: #define        MT_DATA         1       /* dynamic (data) allocation */
                    165: #define        MT_HEADER       2       /* packet header */
                    166: #define        MT_SOCKET       3       /* socket structure */
                    167: #define        MT_PCB          4       /* protocol control block */
                    168: #define        MT_RTABLE       5       /* routing tables */
                    169: #define        MT_HTABLE       6       /* IMP host tables */
                    170: #define        MT_ATABLE       7       /* address resolution tables */
                    171: #define        MT_SONAME       8       /* socket name */
                    172: #define        MT_SOOPTS       10      /* socket options */
                    173: #define        MT_FTABLE       11      /* fragment reassembly header */
                    174: #define        MT_RIGHTS       12      /* access rights */
                    175: #define        MT_IFADDR       13      /* interface address */
                    176: #define MT_CONTROL     14      /* extra-data protocol message */
                    177: #define MT_OOBDATA     15      /* expedited data  */
                    178: #define MT_MAX         32      /* enough? */
                    179: 
                    180: /* flags to m_get/MGET */
                    181: #define        M_DONTWAIT      0
                    182: #define        M_WAIT          1
                    183: 
                    184: /*
                    185:  * mbuf utility macros:
                    186:  *
                    187:  *     MBUFLOCK(code)
                    188:  * prevents a section of code from from being interrupted by network
                    189:  * drivers.
                    190:  */
                    191: #define MBUF_LOCK()
                    192: #define MBUF_UNLOCK()
                    193: #define MBUF_LOCKINIT()
                    194:  
                    195: /*
                    196:  * mbuf allocation/deallocation macros:
                    197:  *
                    198:  *     MGET(struct mbuf *m, int how, int type)
                    199:  * allocates an mbuf and initializes it to contain internal data.
                    200:  *
                    201:  *     MGETHDR(struct mbuf *m, int how, int type)
                    202:  * allocates an mbuf and initializes it to contain a packet header
                    203:  * and internal data.
                    204:  */
                    205: 
                    206: #ifdef DIAGNOSE
                    207: #define MCHECK(m) if ((m)->m_type != MT_FREE) panic("mget")
                    208: #else
                    209: #define MCHECK(m)
                    210: #endif
                    211: 
                    212: extern struct mbuf *mfree;                             /* mbuf free list */
                    213: 
                    214: #define _MINTGET(m, type) {                                            \
                    215:        int _ms = splimp();                                             \
                    216:        MBUF_LOCK();                                                    \
                    217:        if (((m) = mfree) != 0) {                                       \
                    218:                MCHECK(m);                                                              \
                    219:                ++mclrefcnt[mtocl(m)];                                  \
                    220:                mbstat.m_mtypes[MT_FREE]--;                             \
                    221:                mbstat.m_mtypes[type]++;                                \
                    222:                mfree = (m)->m_next;                                    \
                    223:        }                                                               \
                    224:        MBUF_UNLOCK();                                                  \
                    225:        splx(_ms);                                                      \
                    226: }
                    227:        
                    228: #define        MGET(m, how, type) {                                            \
                    229:        _MINTGET(m, type);                                              \
                    230:        if (m) {                                                        \
                    231:                (m)->m_next = (m)->m_nextpkt = 0;                       \
                    232:                (m)->m_type = (type);                                   \
                    233:                (m)->m_data = (m)->m_dat;                               \
                    234:                (m)->m_flags = 0;                                       \
                    235:        } else                                                          \
                    236:                (m) = m_retry((how), (type));                           \
                    237: }
                    238: 
                    239: #define        MGETHDR(m, how, type) {                                         \
                    240:        _MINTGET(m, type);                                              \
                    241:        if (m) {                                                        \
                    242:                (m)->m_next = (m)->m_nextpkt = 0;                       \
                    243:                (m)->m_type = (type);                                   \
                    244:                (m)->m_data = (m)->m_pktdat;                            \
                    245:                (m)->m_flags = M_PKTHDR;                                \
                    246:        } else                                                          \
                    247:                (m) = m_retryhdr((how), (type));                        \
                    248: }
                    249: 
                    250: /*
                    251:  * Mbuf cluster macros.
                    252:  * MCLALLOC(caddr_t p, int how) allocates an mbuf cluster.
                    253:  * MCLGET adds such clusters to a normal mbuf;
                    254:  * the flag M_EXT is set upon success.
                    255:  * MCLFREE releases a reference to a cluster allocated by MCLALLOC,
                    256:  * freeing the cluster if the reference count has reached 0.
                    257:  *
                    258:  * Normal mbuf clusters are normally treated as character arrays
                    259:  * after allocation, but use the first word of the buffer as a free list
                    260:  * pointer while on the free list.
                    261:  */
                    262: union mcluster {
                    263:        union   mcluster *mcl_next;
                    264:        char    mcl_buf[MCLBYTES];
                    265: };
                    266: 
                    267: #define        MCLALLOC(p, how) {                                                      \
                    268:        int _ms = splimp();                                                     \
                    269:        MBUF_LOCK();                                                                    \
                    270:        (void)m_clalloc(1, (how));                                              \
                    271:        if (((p) = (caddr_t)mclfree)) {                                         \
                    272:                ++mclrefcnt[mtocl(p)];                                          \
                    273:                mbstat.m_clfree--;                                                      \
                    274:                mclfree = ((union mcluster *)(p))->mcl_next;            \
                    275:        }                                                               \
                    276:        MBUF_UNLOCK();                                                  \
                    277:        splx(_ms);                                                      \
                    278: }
                    279: 
                    280: #define        MCLGET(m, how) {                                                \
                    281:        MCLALLOC((m)->m_ext.ext_buf, (how));                            \
                    282:        if ((m)->m_ext.ext_buf) {                                       \
                    283:                (m)->m_data = (m)->m_ext.ext_buf;                       \
                    284:                (m)->m_flags |= M_EXT;                                  \
                    285:                (m)->m_ext.ext_size = MCLBYTES;                         \
                    286:                (m)->m_ext.ext_free = 0;                                \
                    287:                (m)->m_ext.ext_refs.forward = (m)->m_ext.ext_refs.backward = \
                    288:                        &(m)->m_ext.ext_refs; \
                    289:        }                                                               \
                    290: }
                    291: 
                    292: #define        MCLFREE(p) {                                                    \
                    293:        int _ms = splimp();                                             \
                    294:        MBUF_LOCK();                                                    \
                    295:        if (--mclrefcnt[mtocl(p)] == 0) {                               \
                    296:                ((union mcluster *)(p))->mcl_next = mclfree;            \
                    297:                mclfree = (union mcluster *)(p);                        \
                    298:                mbstat.m_clfree++;                                      \
                    299:        }                                                               \
                    300:        MBUF_UNLOCK();                                                  \
                    301:        splx(_ms);                                                      \
                    302: }
                    303: 
                    304: #define MCLHASREFERENCE(m) \
                    305:        ((m)->m_ext.ext_refs.forward != &((m)->m_ext.ext_refs))
                    306: 
                    307: /*
                    308:  * MFREE(struct mbuf *m, struct mbuf *n)
                    309:  * Free a single mbuf and associated external storage.
                    310:  * Place the successor, if any, in n.
                    311:  */
                    312: 
                    313: #define        MFREE(m, n) (n) = m_free(m)
                    314: 
                    315: /*
                    316:  * Copy mbuf pkthdr from from to to.
                    317:  * from must have M_PKTHDR set, and to must be empty.
                    318:  */
                    319: #define        M_COPY_PKTHDR(to, from) {                                       \
                    320:        (to)->m_pkthdr = (from)->m_pkthdr;                              \
                    321:        (to)->m_flags = (from)->m_flags & M_COPYFLAGS;                  \
                    322:        (to)->m_data = (to)->m_pktdat;                                  \
                    323: }
                    324: 
                    325: /*
                    326:  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
                    327:  * an object of the specified size at the end of the mbuf, longword aligned.
                    328:  */
                    329: #define        M_ALIGN(m, len)                                                 \
                    330:        { (m)->m_data += (MLEN - (len)) &~ (sizeof(long) - 1); }
                    331: /*
                    332:  * As above, for mbufs allocated with m_gethdr/MGETHDR
                    333:  * or initialized by M_COPY_PKTHDR.
                    334:  */
                    335: #define        MH_ALIGN(m, len)                                                \
                    336:        { (m)->m_data += (MHLEN - (len)) &~ (sizeof(long) - 1); }
                    337: 
                    338: /*
                    339:  * Compute the amount of space available
                    340:  * before the current start of data in an mbuf.
                    341:  * Subroutine - data not available if certain references.
                    342:  */
                    343: int m_leadingspace(struct mbuf *);
                    344: #define        M_LEADINGSPACE(m)       m_leadingspace(m)
                    345: 
                    346: /*
                    347:  * Compute the amount of space available
                    348:  * after the end of data in an mbuf.
                    349:  * Subroutine - data not available if certain references.
                    350:  */
                    351: int m_trailingspace(struct mbuf *);
                    352: #define        M_TRAILINGSPACE(m)      m_trailingspace(m)
                    353: 
                    354: /*
                    355:  * Arrange to prepend space of size plen to mbuf m.
                    356:  * If a new mbuf must be allocated, how specifies whether to wait.
                    357:  * If how is M_DONTWAIT and allocation fails, the original mbuf chain
                    358:  * is freed and m is set to NULL.
                    359:  */
                    360: #define        M_PREPEND(m, plen, how) {                                       \
                    361:        if (M_LEADINGSPACE(m) >= (plen)) {                              \
                    362:                (m)->m_data -= (plen);                                  \
                    363:                (m)->m_len += (plen);                                   \
                    364:        } else                                                          \
                    365:                (m) = m_prepend((m), (plen), (how));                    \
                    366:        if ((m) && (m)->m_flags & M_PKTHDR)                             \
                    367:                (m)->m_pkthdr.len += (plen);                            \
                    368: }
                    369: 
                    370: /* change mbuf to new type */
                    371: #define MCHTYPE(m, t) {                                                \
                    372:        int _ms = splimp();                                             \
                    373:        MBUF_LOCK();                                                    \
                    374:        mbstat.m_mtypes[(m)->m_type]--;                                 \
                    375:        mbstat.m_mtypes[t]++;                                           \
                    376:        (m)->m_type = t;                                                \
                    377:        MBUF_UNLOCK();                                                  \
                    378:        splx(_ms);                                                      \
                    379: }
                    380: 
                    381: /* length to m_copy to copy all */
                    382: #define        M_COPYALL       1000000000
                    383: 
                    384: /* compatiblity with 4.3 */
                    385: #define  m_copy(m, o, l)       m_copym((m), (o), (l), M_DONTWAIT)
                    386: 
                    387: /*
                    388:  * Mbuf statistics.
                    389:  */
                    390: struct mbstat {
                    391:        u_long  m_mbufs;        /* mbufs obtained from page pool */
                    392:        u_long  m_clusters;     /* clusters obtained from page pool */
                    393:        u_long  m_spare;        /* spare field */
                    394:        u_long  m_clfree;       /* free clusters */
                    395:        u_long  m_drops;        /* times failed to find space */
                    396:        u_long  m_wait;         /* times waited for space */
                    397:        u_long  m_drain;        /* times drained protocols for space */
                    398:        u_short m_mtypes[256];  /* type specific mbuf allocations */
                    399: };
                    400: 
                    401: #ifdef _KERNEL
                    402: extern union   mcluster *mbutl;        /* virtual address of mclusters */
                    403: extern union   mcluster embutl;        /* virtual address of mclusters */
                    404: extern short   *mclrefcnt;             /* cluster reference counts */
                    405: extern struct  mbstat mbstat;          /* statistics */
                    406: extern int     nmbclusters;            /* number of mapped clusters */
                    407: extern union   mcluster *mclfree;      /* free mapped cluster list */
                    408: extern int     max_linkhdr;            /* largest link-level header */
                    409: extern int     max_protohdr;           /* largest protocol header */
                    410: extern int     max_hdr;                /* largest link+protocol header */
                    411: extern int     max_datalen;            /* MHLEN - max_hdr */
                    412: 
                    413: struct mbuf *m_copym __P((struct mbuf *, int, int, int));
                    414: struct mbuf *m_free __P((struct mbuf *));
                    415: struct mbuf *m_get __P((int, int));
                    416: struct mbuf *m_getclr __P((int, int));
                    417: struct mbuf *m_gethdr __P((int, int));
                    418: struct mbuf *m_prepend __P((struct mbuf *, int, int));
                    419: struct mbuf *m_pullup __P((struct mbuf *, int));
                    420: struct mbuf *m_retry __P((int, int));
                    421: struct mbuf *m_retryhdr __P((int, int));
                    422: void m_adj __P((struct mbuf *, int));
                    423: int     m_clalloc __P((int, int));
                    424: void m_freem __P((struct mbuf *));
                    425: struct mbuf *m_devget __P((char *, int, int, struct ifnet *, void (*)()));
                    426: #endif
                    427: #endif /* !_SYS_MBUF_H_ */

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