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