The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/sys/mbuf.h

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1988, 1993
    3  *      The Regents of the University of California.
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  * 3. Neither the name of the University nor the names of its contributors
   15  *    may be used to endorse or promote products derived from this software
   16  *    without specific prior written permission.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   28  * SUCH DAMAGE.
   29  *
   30  *      @(#)mbuf.h      8.5 (Berkeley) 2/19/95
   31  * $FreeBSD$
   32  */
   33 
   34 #ifndef _SYS_MBUF_H_
   35 #define _SYS_MBUF_H_
   36 
   37 /* XXX: These includes suck. Sorry! */
   38 #include <sys/queue.h>
   39 #ifdef _KERNEL
   40 #include <sys/systm.h>
   41 #include <vm/uma.h>
   42 #ifdef WITNESS
   43 #include <sys/lock.h>
   44 #endif
   45 #endif
   46 
   47 /*
   48  * Mbufs are of a single size, MSIZE (sys/param.h), which includes overhead.
   49  * An mbuf may add a single "mbuf cluster" of size MCLBYTES (also in
   50  * sys/param.h), which has no additional overhead and is used instead of the
   51  * internal data area; this is done when at least MINCLSIZE of data must be
   52  * stored.  Additionally, it is possible to allocate a separate buffer
   53  * externally and attach it to the mbuf in a way similar to that of mbuf
   54  * clusters.
   55  */
   56 #define MLEN            (MSIZE - sizeof(struct m_hdr))  /* normal data len */
   57 #define MHLEN           (MLEN - sizeof(struct pkthdr))  /* data len w/pkthdr */
   58 #define MINCLSIZE       (MHLEN + 1)     /* smallest amount to put in cluster */
   59 #define M_MAXCOMPRESS   (MHLEN / 2)     /* max amount to copy for compression */
   60 
   61 #ifdef _KERNEL
   62 /*-
   63  * Macros for type conversion:
   64  * mtod(m, t)   -- Convert mbuf pointer to data pointer of correct type.
   65  * dtom(x)      -- Convert data pointer within mbuf to mbuf pointer (XXX).
   66  */
   67 #define mtod(m, t)      ((t)((m)->m_data))
   68 #define dtom(x)         ((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1)))
   69 
   70 /*
   71  * Argument structure passed to UMA routines during mbuf and packet
   72  * allocations.
   73  */
   74 struct mb_args {
   75         int     flags;  /* Flags for mbuf being allocated */
   76         short   type;   /* Type of mbuf being allocated */
   77 };
   78 #endif /* _KERNEL */
   79 
   80 #if defined(__LP64__)
   81 #define M_HDR_PAD    6
   82 #else
   83 #define M_HDR_PAD    2
   84 #endif
   85 
   86 /*
   87  * Header present at the beginning of every mbuf.
   88  */
   89 struct m_hdr {
   90         struct mbuf     *mh_next;       /* next buffer in chain */
   91         struct mbuf     *mh_nextpkt;    /* next chain in queue/record */
   92         caddr_t          mh_data;       /* location of data */
   93         int              mh_len;        /* amount of data in this mbuf */
   94         int              mh_flags;      /* flags; see below */
   95         short            mh_type;       /* type of data in this mbuf */
   96         uint8_t          pad[M_HDR_PAD];/* word align                  */
   97 };
   98 
   99 /*
  100  * Packet tag structure (see below for details).
  101  */
  102 struct m_tag {
  103         SLIST_ENTRY(m_tag)      m_tag_link;     /* List of packet tags */
  104         u_int16_t               m_tag_id;       /* Tag ID */
  105         u_int16_t               m_tag_len;      /* Length of data */
  106         u_int32_t               m_tag_cookie;   /* ABI/Module ID */
  107         void                    (*m_tag_free)(struct m_tag *);
  108 };
  109 
  110 /*
  111  * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
  112  */
  113 struct pkthdr {
  114         struct ifnet    *rcvif;         /* rcv interface */
  115         /* variables for ip and tcp reassembly */
  116         void            *header;        /* pointer to packet header */
  117         int              len;           /* total packet length */
  118         /* variables for hardware checksum */
  119         int              csum_flags;    /* flags regarding checksum */
  120         int              csum_data;     /* data field used by csum routines */
  121         u_int16_t        tso_segsz;     /* TSO segment size */
  122         u_int16_t        ether_vtag;    /* Ethernet 802.1p+q vlan tag */
  123         SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
  124 };
  125 
  126 /*
  127  * Description of external storage mapped into mbuf; valid only if M_EXT is
  128  * set.
  129  */
  130 struct m_ext {
  131         caddr_t          ext_buf;       /* start of buffer */
  132         void            (*ext_free)     /* free routine if not the usual */
  133                             (void *, void *);
  134         void            *ext_args;      /* optional argument pointer */
  135         u_int            ext_size;      /* size of buffer, for ext_free */
  136         volatile u_int  *ref_cnt;       /* pointer to ref count info */
  137         int              ext_type;      /* type of external storage */
  138 };
  139 
  140 /*
  141  * The core of the mbuf object along with some shortcut defines for practical
  142  * purposes.
  143  */
  144 struct mbuf {
  145         struct m_hdr    m_hdr;
  146         union {
  147                 struct {
  148                         struct pkthdr   MH_pkthdr;      /* M_PKTHDR set */
  149                         union {
  150                                 struct m_ext    MH_ext; /* M_EXT set */
  151                                 char            MH_databuf[MHLEN];
  152                         } MH_dat;
  153                 } MH;
  154                 char    M_databuf[MLEN];                /* !M_PKTHDR, !M_EXT */
  155         } M_dat;
  156 };
  157 #define m_next          m_hdr.mh_next
  158 #define m_len           m_hdr.mh_len
  159 #define m_data          m_hdr.mh_data
  160 #define m_type          m_hdr.mh_type
  161 #define m_flags         m_hdr.mh_flags
  162 #define m_nextpkt       m_hdr.mh_nextpkt
  163 #define m_act           m_nextpkt
  164 #define m_pkthdr        M_dat.MH.MH_pkthdr
  165 #define m_ext           M_dat.MH.MH_dat.MH_ext
  166 #define m_pktdat        M_dat.MH.MH_dat.MH_databuf
  167 #define m_dat           M_dat.M_databuf
  168 
  169 /*
  170  * mbuf flags.
  171  */
  172 #define M_EXT           0x0001  /* has associated external storage */
  173 #define M_PKTHDR        0x0002  /* start of record */
  174 #define M_EOR           0x0004  /* end of record */
  175 #define M_RDONLY        0x0008  /* associated data is marked read-only */
  176 #define M_PROTO1        0x0010  /* protocol-specific */
  177 #define M_PROTO2        0x0020  /* protocol-specific */
  178 #define M_PROTO3        0x0040  /* protocol-specific */
  179 #define M_PROTO4        0x0080  /* protocol-specific */
  180 #define M_PROTO5        0x0100  /* protocol-specific */
  181 #define M_NOTIFICATION  M_PROTO5/* SCTP notification */
  182 #define M_SKIP_FIREWALL 0x4000  /* skip firewall processing */
  183 #define M_FREELIST      0x8000  /* mbuf is on the free list */
  184 
  185 /*
  186  * mbuf pkthdr flags (also stored in m_flags).
  187  */
  188 #define M_BCAST         0x0200  /* send/received as link-level broadcast */
  189 #define M_MCAST         0x0400  /* send/received as link-level multicast */
  190 #define M_FRAG          0x0800  /* packet is a fragment of a larger packet */
  191 #define M_FIRSTFRAG     0x1000  /* packet is first fragment */
  192 #define M_LASTFRAG      0x2000  /* packet is last fragment */
  193 #define M_VLANTAG       0x10000 /* ether_vtag is valid */
  194 #define M_PROMISC       0x20000 /* packet was not for us */
  195 #define M_NOFREE        0x40000 /* do not free mbuf - it is embedded in the cluster */
  196 
  197 /*
  198  * External buffer types: identify ext_buf type.
  199  */
  200 #define EXT_CLUSTER     1       /* mbuf cluster */
  201 #define EXT_SFBUF       2       /* sendfile(2)'s sf_bufs */
  202 #define EXT_JUMBOP      3       /* jumbo cluster 4096 bytes */
  203 #define EXT_JUMBO9      4       /* jumbo cluster 9216 bytes */
  204 #define EXT_JUMBO16     5       /* jumbo cluster 16184 bytes */
  205 #define EXT_PACKET      6       /* mbuf+cluster from packet zone */
  206 #define EXT_MBUF        7       /* external mbuf reference (M_IOVEC) */
  207 #define EXT_NET_DRV     100     /* custom ext_buf provided by net driver(s) */
  208 #define EXT_MOD_TYPE    200     /* custom module's ext_buf type */
  209 #define EXT_DISPOSABLE  300     /* can throw this buffer away w/page flipping */
  210 #define EXT_EXTREF      400     /* has externally maintained ref_cnt ptr */
  211 
  212 /*
  213  * Flags copied when copying m_pkthdr.
  214  */
  215 #define M_COPYFLAGS     (M_PKTHDR|M_EOR|M_RDONLY|M_PROTO1|M_PROTO1|M_PROTO2|\
  216                             M_PROTO3|M_PROTO4|M_PROTO5|M_SKIP_FIREWALL|\
  217                             M_BCAST|M_MCAST|M_FRAG|M_FIRSTFRAG|M_LASTFRAG|\
  218                             M_VLANTAG|M_PROMISC)
  219 
  220 /*
  221  * Flags to purge when crossing layers.
  222  */
  223 #define M_PROTOFLAGS    (M_PROTO1|M_PROTO2|M_PROTO3|M_PROTO4|M_PROTO5)
  224 
  225 /*
  226  * Flags indicating hw checksum support and sw checksum requirements.  This
  227  * field can be directly tested against if_data.ifi_hwassist.
  228  */
  229 #define CSUM_IP                 0x0001          /* will csum IP */
  230 #define CSUM_TCP                0x0002          /* will csum TCP */
  231 #define CSUM_UDP                0x0004          /* will csum UDP */
  232 #define CSUM_IP_FRAGS           0x0008          /* will csum IP fragments */
  233 #define CSUM_FRAGMENT           0x0010          /* will do IP fragmentation */
  234 #define CSUM_TSO                0x0020          /* will do TSO */
  235 
  236 #define CSUM_IP_CHECKED         0x0100          /* did csum IP */
  237 #define CSUM_IP_VALID           0x0200          /*   ... the csum is valid */
  238 #define CSUM_DATA_VALID         0x0400          /* csum_data field is valid */
  239 #define CSUM_PSEUDO_HDR         0x0800          /* csum_data has pseudo hdr */
  240 
  241 #define CSUM_DELAY_DATA         (CSUM_TCP | CSUM_UDP)
  242 #define CSUM_DELAY_IP           (CSUM_IP)       /* XXX add ipv6 here too? */
  243 
  244 /*
  245  * mbuf types.
  246  */
  247 #define MT_NOTMBUF      0       /* USED INTERNALLY ONLY! Object is not mbuf */
  248 #define MT_DATA         1       /* dynamic (data) allocation */
  249 #define MT_HEADER       MT_DATA /* packet header, use M_PKTHDR instead */
  250 #define MT_SONAME       8       /* socket name */
  251 #define MT_CONTROL      14      /* extra-data protocol message */
  252 #define MT_OOBDATA      15      /* expedited data  */
  253 #define MT_NTYPES       16      /* number of mbuf types for mbtypes[] */
  254 
  255 #define MT_NOINIT       255     /* Not a type but a flag to allocate
  256                                    a non-initialized mbuf */
  257 
  258 #define MB_NOTAGS       0x1UL   /* no tags attached to mbuf */
  259 
  260 /*
  261  * General mbuf allocator statistics structure.
  262  *
  263  * Many of these statistics are no longer used; we instead track many
  264  * allocator statistics through UMA's built in statistics mechanism.
  265  */
  266 struct mbstat {
  267         u_long  m_mbufs;        /* XXX */
  268         u_long  m_mclusts;      /* XXX */
  269 
  270         u_long  m_drain;        /* times drained protocols for space */
  271         u_long  m_mcfail;       /* XXX: times m_copym failed */
  272         u_long  m_mpfail;       /* XXX: times m_pullup failed */
  273         u_long  m_msize;        /* length of an mbuf */
  274         u_long  m_mclbytes;     /* length of an mbuf cluster */
  275         u_long  m_minclsize;    /* min length of data to allocate a cluster */
  276         u_long  m_mlen;         /* length of data in an mbuf */
  277         u_long  m_mhlen;        /* length of data in a header mbuf */
  278 
  279         /* Number of mbtypes (gives # elems in mbtypes[] array: */
  280         short   m_numtypes;
  281 
  282         /* XXX: Sendfile stats should eventually move to their own struct */
  283         u_long  sf_iocnt;       /* times sendfile had to do disk I/O */
  284         u_long  sf_allocfail;   /* times sfbuf allocation failed */
  285         u_long  sf_allocwait;   /* times sfbuf allocation had to wait */
  286 };
  287 
  288 /*
  289  * Flags specifying how an allocation should be made.
  290  *
  291  * The flag to use is as follows:
  292  * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
  293  * - M_WAIT or M_WAITOK or M_TRYWAIT from wherever it is safe to block.
  294  *
  295  * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly and
  296  * if we cannot allocate immediately we may return NULL, whereas
  297  * M_WAIT/M_WAITOK/M_TRYWAIT means that if we cannot allocate resources we
  298  * will block until they are available, and thus never return NULL.
  299  *
  300  * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
  301  */
  302 #define MBTOM(how)      (how)
  303 #define M_DONTWAIT      M_NOWAIT
  304 #define M_TRYWAIT       M_WAITOK
  305 #define M_WAIT          M_WAITOK
  306 
  307 /*
  308  * String names of mbuf-related UMA(9) and malloc(9) types.  Exposed to
  309  * !_KERNEL so that monitoring tools can look up the zones with
  310  * libmemstat(3).
  311  */
  312 #define MBUF_MEM_NAME           "mbuf"
  313 #define MBUF_CLUSTER_MEM_NAME   "mbuf_cluster"
  314 #define MBUF_PACKET_MEM_NAME    "mbuf_packet"
  315 #define MBUF_JUMBOP_MEM_NAME    "mbuf_jumbo_pagesize"
  316 #define MBUF_JUMBO9_MEM_NAME    "mbuf_jumbo_9k"
  317 #define MBUF_JUMBO16_MEM_NAME   "mbuf_jumbo_16k"
  318 #define MBUF_TAG_MEM_NAME       "mbuf_tag"
  319 #define MBUF_EXTREFCNT_MEM_NAME "mbuf_ext_refcnt"
  320 
  321 #ifdef _KERNEL
  322 
  323 #ifdef WITNESS
  324 #define MBUF_CHECKSLEEP(how) do {                                       \
  325         if (how == M_WAITOK)                                            \
  326                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,         \
  327                     "Sleeping in \"%s\"", __func__);                    \
  328 } while (0)
  329 #else
  330 #define MBUF_CHECKSLEEP(how)
  331 #endif
  332 
  333 /*
  334  * Network buffer allocation API
  335  *
  336  * The rest of it is defined in kern/kern_mbuf.c
  337  */
  338 
  339 extern uma_zone_t       zone_mbuf;
  340 extern uma_zone_t       zone_clust;
  341 extern uma_zone_t       zone_pack;
  342 extern uma_zone_t       zone_jumbop;
  343 extern uma_zone_t       zone_jumbo9;
  344 extern uma_zone_t       zone_jumbo16;
  345 extern uma_zone_t       zone_ext_refcnt;
  346 
  347 static __inline struct mbuf     *m_getcl(int how, short type, int flags);
  348 static __inline struct mbuf     *m_get(int how, short type);
  349 static __inline struct mbuf     *m_gethdr(int how, short type);
  350 static __inline struct mbuf     *m_getjcl(int how, short type, int flags,
  351                                     int size);
  352 static __inline struct mbuf     *m_getclr(int how, short type); /* XXX */
  353 static __inline struct mbuf     *m_free(struct mbuf *m);
  354 static __inline void             m_clget(struct mbuf *m, int how);
  355 static __inline void            *m_cljget(struct mbuf *m, int how, int size);
  356 static __inline void             m_chtype(struct mbuf *m, short new_type);
  357 void                             mb_free_ext(struct mbuf *);
  358 static __inline struct mbuf     *m_last(struct mbuf *m);
  359 
  360 static __inline int
  361 m_gettype(int size)
  362 {
  363         int type;
  364         
  365         switch (size) {
  366         case MSIZE:
  367                 type = EXT_MBUF;
  368                 break;
  369         case MCLBYTES:
  370                 type = EXT_CLUSTER;
  371                 break;
  372 #if MJUMPAGESIZE != MCLBYTES
  373         case MJUMPAGESIZE:
  374                 type = EXT_JUMBOP;
  375                 break;
  376 #endif
  377         case MJUM9BYTES:
  378                 type = EXT_JUMBO9;
  379                 break;
  380         case MJUM16BYTES:
  381                 type = EXT_JUMBO16;
  382                 break;
  383         default:
  384                 panic("%s: m_getjcl: invalid cluster size", __func__);
  385         }
  386 
  387         return (type);
  388 }
  389 
  390 static __inline uma_zone_t
  391 m_getzone(int size)
  392 {
  393         uma_zone_t zone;
  394         
  395         switch (size) {
  396         case MSIZE:
  397                 zone = zone_mbuf;
  398                 break;
  399         case MCLBYTES:
  400                 zone = zone_clust;
  401                 break;
  402 #if MJUMPAGESIZE != MCLBYTES
  403         case MJUMPAGESIZE:
  404                 zone = zone_jumbop;
  405                 break;
  406 #endif
  407         case MJUM9BYTES:
  408                 zone = zone_jumbo9;
  409                 break;
  410         case MJUM16BYTES:
  411                 zone = zone_jumbo16;
  412                 break;
  413         default:
  414                 panic("%s: m_getjcl: invalid cluster type", __func__);
  415         }
  416 
  417         return (zone);
  418 }
  419 
  420 static __inline struct mbuf *
  421 m_get(int how, short type)
  422 {
  423         struct mb_args args;
  424 
  425         args.flags = 0;
  426         args.type = type;
  427         return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
  428 }
  429 
  430 /*
  431  * XXX This should be deprecated, very little use.
  432  */
  433 static __inline struct mbuf *
  434 m_getclr(int how, short type)
  435 {
  436         struct mbuf *m;
  437         struct mb_args args;
  438 
  439         args.flags = 0;
  440         args.type = type;
  441         m = uma_zalloc_arg(zone_mbuf, &args, how);
  442         if (m != NULL)
  443                 bzero(m->m_data, MLEN);
  444         return (m);
  445 }
  446 
  447 static __inline struct mbuf *
  448 m_gethdr(int how, short type)
  449 {
  450         struct mb_args args;
  451 
  452         args.flags = M_PKTHDR;
  453         args.type = type;
  454         return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
  455 }
  456 
  457 static __inline struct mbuf *
  458 m_getcl(int how, short type, int flags)
  459 {
  460         struct mb_args args;
  461 
  462         args.flags = flags;
  463         args.type = type;
  464         return ((struct mbuf *)(uma_zalloc_arg(zone_pack, &args, how)));
  465 }
  466 
  467 /*
  468  * m_getjcl() returns an mbuf with a cluster of the specified size attached.
  469  * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
  470  *
  471  * XXX: This is rather large, should be real function maybe.
  472  */
  473 static __inline struct mbuf *
  474 m_getjcl(int how, short type, int flags, int size)
  475 {
  476         struct mb_args args;
  477         struct mbuf *m, *n;
  478         uma_zone_t zone;
  479 
  480         args.flags = flags;
  481         args.type = type;
  482 
  483         m = uma_zalloc_arg(zone_mbuf, &args, how);
  484         if (m == NULL)
  485                 return (NULL);
  486 
  487         zone = m_getzone(size);
  488         n = uma_zalloc_arg(zone, m, how);
  489         if (n == NULL) {
  490                 uma_zfree(zone_mbuf, m);
  491                 return (NULL);
  492         }
  493         return (m);
  494 }
  495 
  496 static __inline void
  497 m_free_fast(struct mbuf *m)
  498 {
  499         KASSERT(SLIST_EMPTY(&m->m_pkthdr.tags), ("doing fast free of mbuf with tags"));
  500 
  501         uma_zfree_arg(zone_mbuf, m, (void *)MB_NOTAGS);
  502 }
  503 
  504 static __inline struct mbuf *
  505 m_free(struct mbuf *m)
  506 {
  507         struct mbuf *n = m->m_next;
  508 
  509         if (m->m_flags & M_EXT)
  510                 mb_free_ext(m);
  511         else if ((m->m_flags & M_NOFREE) == 0)
  512                 uma_zfree(zone_mbuf, m);
  513         return (n);
  514 }
  515 
  516 static __inline void
  517 m_clget(struct mbuf *m, int how)
  518 {
  519 
  520         if (m->m_flags & M_EXT)
  521                 printf("%s: %p mbuf already has cluster\n", __func__, m);
  522         m->m_ext.ext_buf = (char *)NULL;
  523         uma_zalloc_arg(zone_clust, m, how);
  524         /*
  525          * On a cluster allocation failure, drain the packet zone and retry,
  526          * we might be able to loosen a few clusters up on the drain.
  527          */
  528         if ((how & M_NOWAIT) && (m->m_ext.ext_buf == NULL)) {
  529                 zone_drain(zone_pack);
  530                 uma_zalloc_arg(zone_clust, m, how);
  531         }
  532 }
  533 
  534 /*
  535  * m_cljget() is different from m_clget() as it can allocate clusters without
  536  * attaching them to an mbuf.  In that case the return value is the pointer
  537  * to the cluster of the requested size.  If an mbuf was specified, it gets
  538  * the cluster attached to it and the return value can be safely ignored.
  539  * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
  540  */
  541 static __inline void *
  542 m_cljget(struct mbuf *m, int how, int size)
  543 {
  544         uma_zone_t zone;
  545 
  546         if (m && m->m_flags & M_EXT)
  547                 printf("%s: %p mbuf already has cluster\n", __func__, m);
  548         if (m != NULL)
  549                 m->m_ext.ext_buf = NULL;
  550 
  551         zone = m_getzone(size);
  552         return (uma_zalloc_arg(zone, m, how));
  553 }
  554 
  555 static __inline void
  556 m_cljset(struct mbuf *m, void *cl, int type)
  557 {
  558         uma_zone_t zone;
  559         int size;
  560         
  561         switch (type) {
  562         case EXT_CLUSTER:
  563                 size = MCLBYTES;
  564                 zone = zone_clust;
  565                 break;
  566 #if MJUMPAGESIZE != MCLBYTES
  567         case EXT_JUMBOP:
  568                 size = MJUMPAGESIZE;
  569                 zone = zone_jumbop;
  570                 break;
  571 #endif
  572         case EXT_JUMBO9:
  573                 size = MJUM9BYTES;
  574                 zone = zone_jumbo9;
  575                 break;
  576         case EXT_JUMBO16:
  577                 size = MJUM16BYTES;
  578                 zone = zone_jumbo16;
  579                 break;
  580         default:
  581                 panic("unknown cluster type");
  582                 break;
  583         }
  584 
  585         m->m_data = m->m_ext.ext_buf = cl;
  586         m->m_ext.ext_free = m->m_ext.ext_args = NULL;
  587         m->m_ext.ext_size = size;
  588         m->m_ext.ext_type = type;
  589         m->m_ext.ref_cnt = uma_find_refcnt(zone, cl);
  590         m->m_flags |= M_EXT;
  591 
  592 }
  593 
  594 static __inline void
  595 m_chtype(struct mbuf *m, short new_type)
  596 {
  597 
  598         m->m_type = new_type;
  599 }
  600 
  601 static __inline struct mbuf *
  602 m_last(struct mbuf *m)
  603 {
  604 
  605         while (m->m_next)
  606                 m = m->m_next;
  607         return (m);
  608 }
  609 
  610 /*
  611  * mbuf, cluster, and external object allocation macros (for compatibility
  612  * purposes).
  613  */
  614 #define M_MOVE_PKTHDR(to, from) m_move_pkthdr((to), (from))
  615 #define MGET(m, how, type)      ((m) = m_get((how), (type)))
  616 #define MGETHDR(m, how, type)   ((m) = m_gethdr((how), (type)))
  617 #define MCLGET(m, how)          m_clget((m), (how))
  618 #define MEXTADD(m, buf, size, free, args, flags, type)                  \
  619     m_extadd((m), (caddr_t)(buf), (size), (free), (args), (flags), (type))
  620 #define m_getm(m, len, how, type)                                       \
  621     m_getm2((m), (len), (how), (type), M_PKTHDR)
  622 
  623 /*
  624  * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
  625  * be both the local data payload, or an external buffer area, depending on
  626  * whether M_EXT is set).
  627  */
  628 #define M_WRITABLE(m)   (!((m)->m_flags & M_RDONLY) &&                  \
  629                          (!(((m)->m_flags & M_EXT)) ||                  \
  630                          (*((m)->m_ext.ref_cnt) == 1)) )                \
  631 
  632 /* Check if the supplied mbuf has a packet header, or else panic. */
  633 #define M_ASSERTPKTHDR(m)                                               \
  634         KASSERT(m != NULL && m->m_flags & M_PKTHDR,                     \
  635             ("%s: no mbuf packet header!", __func__))
  636 
  637 /*
  638  * Ensure that the supplied mbuf is a valid, non-free mbuf.
  639  *
  640  * XXX: Broken at the moment.  Need some UMA magic to make it work again.
  641  */
  642 #define M_ASSERTVALID(m)                                                \
  643         KASSERT((((struct mbuf *)m)->m_flags & 0) == 0,                 \
  644             ("%s: attempted use of a free mbuf!", __func__))
  645 
  646 /*
  647  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place an
  648  * object of the specified size at the end of the mbuf, longword aligned.
  649  */
  650 #define M_ALIGN(m, len) do {                                            \
  651         KASSERT(!((m)->m_flags & (M_PKTHDR|M_EXT)),                     \
  652                 ("%s: M_ALIGN not normal mbuf", __func__));             \
  653         KASSERT((m)->m_data == (m)->m_dat,                              \
  654                 ("%s: M_ALIGN not a virgin mbuf", __func__));           \
  655         (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1);            \
  656 } while (0)
  657 
  658 /*
  659  * As above, for mbufs allocated with m_gethdr/MGETHDR or initialized by
  660  * M_DUP/MOVE_PKTHDR.
  661  */
  662 #define MH_ALIGN(m, len) do {                                           \
  663         KASSERT((m)->m_flags & M_PKTHDR && !((m)->m_flags & M_EXT),     \
  664                 ("%s: MH_ALIGN not PKTHDR mbuf", __func__));            \
  665         KASSERT((m)->m_data == (m)->m_pktdat,                           \
  666                 ("%s: MH_ALIGN not a virgin mbuf", __func__));          \
  667         (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1);           \
  668 } while (0)
  669 
  670 /*
  671  * Compute the amount of space available before the current start of data in
  672  * an mbuf.
  673  *
  674  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  675  * of checking writability of the mbuf data area rests solely with the caller.
  676  */
  677 #define M_LEADINGSPACE(m)                                               \
  678         ((m)->m_flags & M_EXT ?                                         \
  679             (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0):     \
  680             (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat :     \
  681             (m)->m_data - (m)->m_dat)
  682 
  683 /*
  684  * Compute the amount of space available after the end of data in an mbuf.
  685  *
  686  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  687  * of checking writability of the mbuf data area rests solely with the caller.
  688  */
  689 #define M_TRAILINGSPACE(m)                                              \
  690         ((m)->m_flags & M_EXT ?                                         \
  691             (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size   \
  692                 - ((m)->m_data + (m)->m_len) : 0) :                     \
  693             &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
  694 
  695 /*
  696  * Arrange to prepend space of size plen to mbuf m.  If a new mbuf must be
  697  * allocated, how specifies whether to wait.  If the allocation fails, the
  698  * original mbuf chain is freed and m is set to NULL.
  699  */
  700 #define M_PREPEND(m, plen, how) do {                                    \
  701         struct mbuf **_mmp = &(m);                                      \
  702         struct mbuf *_mm = *_mmp;                                       \
  703         int _mplen = (plen);                                            \
  704         int __mhow = (how);                                             \
  705                                                                         \
  706         MBUF_CHECKSLEEP(how);                                           \
  707         if (M_LEADINGSPACE(_mm) >= _mplen) {                            \
  708                 _mm->m_data -= _mplen;                                  \
  709                 _mm->m_len += _mplen;                                   \
  710         } else                                                          \
  711                 _mm = m_prepend(_mm, _mplen, __mhow);                   \
  712         if (_mm != NULL && _mm->m_flags & M_PKTHDR)                     \
  713                 _mm->m_pkthdr.len += _mplen;                            \
  714         *_mmp = _mm;                                                    \
  715 } while (0)
  716 
  717 /*
  718  * Change mbuf to new type.  This is a relatively expensive operation and
  719  * should be avoided.
  720  */
  721 #define MCHTYPE(m, t)   m_chtype((m), (t))
  722 
  723 /* Length to m_copy to copy all. */
  724 #define M_COPYALL       1000000000
  725 
  726 /* Compatibility with 4.3. */
  727 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
  728 
  729 extern int              max_datalen;    /* MHLEN - max_hdr */
  730 extern int              max_hdr;        /* Largest link + protocol header */
  731 extern int              max_linkhdr;    /* Largest link-level header */
  732 extern int              max_protohdr;   /* Largest protocol header */
  733 extern struct mbstat    mbstat;         /* General mbuf stats/infos */
  734 extern int              nmbclusters;    /* Maximum number of clusters */
  735 
  736 struct uio;
  737 
  738 void             m_adj(struct mbuf *, int);
  739 void             m_align(struct mbuf *, int);
  740 int              m_apply(struct mbuf *, int, int,
  741                     int (*)(void *, void *, u_int), void *);
  742 int              m_append(struct mbuf *, int, c_caddr_t);
  743 void             m_cat(struct mbuf *, struct mbuf *);
  744 void             m_extadd(struct mbuf *, caddr_t, u_int,
  745                     void (*)(void *, void *), void *, int, int);
  746 void             m_copyback(struct mbuf *, int, int, c_caddr_t);
  747 void             m_copydata(const struct mbuf *, int, int, caddr_t);
  748 struct mbuf     *m_copym(struct mbuf *, int, int, int);
  749 struct mbuf     *m_copymdata(struct mbuf *, struct mbuf *,
  750                     int, int, int, int);
  751 struct mbuf     *m_copypacket(struct mbuf *, int);
  752 void             m_copy_pkthdr(struct mbuf *, struct mbuf *);
  753 struct mbuf     *m_copyup(struct mbuf *n, int len, int dstoff);
  754 struct mbuf     *m_defrag(struct mbuf *, int);
  755 void             m_demote(struct mbuf *, int);
  756 struct mbuf     *m_devget(char *, int, int, struct ifnet *,
  757                     void (*)(char *, caddr_t, u_int));
  758 struct mbuf     *m_dup(struct mbuf *, int);
  759 int              m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
  760 u_int            m_fixhdr(struct mbuf *);
  761 struct mbuf     *m_fragment(struct mbuf *, int, int);
  762 void             m_freem(struct mbuf *);
  763 struct mbuf     *m_getm2(struct mbuf *, int, int, short, int);
  764 struct mbuf     *m_getptr(struct mbuf *, int, int *);
  765 u_int            m_length(struct mbuf *, struct mbuf **);
  766 void             m_move_pkthdr(struct mbuf *, struct mbuf *);
  767 struct mbuf     *m_prepend(struct mbuf *, int, int);
  768 void             m_print(const struct mbuf *, int);
  769 struct mbuf     *m_pulldown(struct mbuf *, int, int, int *);
  770 struct mbuf     *m_pullup(struct mbuf *, int);
  771 int             m_sanity(struct mbuf *, int);
  772 struct mbuf     *m_split(struct mbuf *, int, int);
  773 struct mbuf     *m_uiotombuf(struct uio *, int, int, int, int);
  774 struct mbuf     *m_unshare(struct mbuf *, int how);
  775 
  776 /*-
  777  * Network packets may have annotations attached by affixing a list of
  778  * "packet tags" to the pkthdr structure.  Packet tags are dynamically
  779  * allocated semi-opaque data structures that have a fixed header
  780  * (struct m_tag) that specifies the size of the memory block and a
  781  * <cookie,type> pair that identifies it.  The cookie is a 32-bit unique
  782  * unsigned value used to identify a module or ABI.  By convention this value
  783  * is chosen as the date+time that the module is created, expressed as the
  784  * number of seconds since the epoch (e.g., using date -u +'%s').  The type
  785  * value is an ABI/module-specific value that identifies a particular
  786  * annotation and is private to the module.  For compatibility with systems
  787  * like OpenBSD that define packet tags w/o an ABI/module cookie, the value
  788  * PACKET_ABI_COMPAT is used to implement m_tag_get and m_tag_find
  789  * compatibility shim functions and several tag types are defined below.
  790  * Users that do not require compatibility should use a private cookie value
  791  * so that packet tag-related definitions can be maintained privately.
  792  *
  793  * Note that the packet tag returned by m_tag_alloc has the default memory
  794  * alignment implemented by malloc.  To reference private data one can use a
  795  * construct like:
  796  *
  797  *      struct m_tag *mtag = m_tag_alloc(...);
  798  *      struct foo *p = (struct foo *)(mtag+1);
  799  *
  800  * if the alignment of struct m_tag is sufficient for referencing members of
  801  * struct foo.  Otherwise it is necessary to embed struct m_tag within the
  802  * private data structure to insure proper alignment; e.g.,
  803  *
  804  *      struct foo {
  805  *              struct m_tag    tag;
  806  *              ...
  807  *      };
  808  *      struct foo *p = (struct foo *) m_tag_alloc(...);
  809  *      struct m_tag *mtag = &p->tag;
  810  */
  811 
  812 /*
  813  * Persistent tags stay with an mbuf until the mbuf is reclaimed.  Otherwise
  814  * tags are expected to ``vanish'' when they pass through a network
  815  * interface.  For most interfaces this happens normally as the tags are
  816  * reclaimed when the mbuf is free'd.  However in some special cases
  817  * reclaiming must be done manually.  An example is packets that pass through
  818  * the loopback interface.  Also, one must be careful to do this when
  819  * ``turning around'' packets (e.g., icmp_reflect).
  820  *
  821  * To mark a tag persistent bit-or this flag in when defining the tag id.
  822  * The tag will then be treated as described above.
  823  */
  824 #define MTAG_PERSISTENT                         0x800
  825 
  826 #define PACKET_TAG_NONE                         0  /* Nadda */
  827 
  828 /* Packet tags for use with PACKET_ABI_COMPAT. */
  829 #define PACKET_TAG_IPSEC_IN_DONE                1  /* IPsec applied, in */
  830 #define PACKET_TAG_IPSEC_OUT_DONE               2  /* IPsec applied, out */
  831 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE         3  /* NIC IPsec crypto done */
  832 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED      4  /* NIC IPsec crypto req'ed */
  833 #define PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO     5  /* NIC notifies IPsec */
  834 #define PACKET_TAG_IPSEC_PENDING_TDB            6  /* Reminder to do IPsec */
  835 #define PACKET_TAG_BRIDGE                       7  /* Bridge processing done */
  836 #define PACKET_TAG_GIF                          8  /* GIF processing done */
  837 #define PACKET_TAG_GRE                          9  /* GRE processing done */
  838 #define PACKET_TAG_IN_PACKET_CHECKSUM           10 /* NIC checksumming done */
  839 #define PACKET_TAG_ENCAP                        11 /* Encap.  processing */
  840 #define PACKET_TAG_IPSEC_SOCKET                 12 /* IPSEC socket ref */
  841 #define PACKET_TAG_IPSEC_HISTORY                13 /* IPSEC history */
  842 #define PACKET_TAG_IPV6_INPUT                   14 /* IPV6 input processing */
  843 #define PACKET_TAG_DUMMYNET                     15 /* dummynet info */
  844 #define PACKET_TAG_DIVERT                       17 /* divert info */
  845 #define PACKET_TAG_IPFORWARD                    18 /* ipforward info */
  846 #define PACKET_TAG_MACLABEL     (19 | MTAG_PERSISTENT) /* MAC label */
  847 #define PACKET_TAG_PF                           21 /* PF + ALTQ information */
  848 #define PACKET_TAG_RTSOCKFAM                    25 /* rtsock sa family */
  849 #define PACKET_TAG_IPOPTIONS                    27 /* Saved IP options */
  850 #define PACKET_TAG_CARP                         28 /* CARP info */
  851 
  852 /* Specific cookies and tags. */
  853 
  854 /* Packet tag routines. */
  855 struct m_tag    *m_tag_alloc(u_int32_t, int, int, int);
  856 void             m_tag_delete(struct mbuf *, struct m_tag *);
  857 void             m_tag_delete_chain(struct mbuf *, struct m_tag *);
  858 void             m_tag_free_default(struct m_tag *);
  859 struct m_tag    *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
  860 struct m_tag    *m_tag_copy(struct m_tag *, int);
  861 int              m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
  862 void             m_tag_delete_nonpersistent(struct mbuf *);
  863 
  864 /*
  865  * Initialize the list of tags associated with an mbuf.
  866  */
  867 static __inline void
  868 m_tag_init(struct mbuf *m)
  869 {
  870 
  871         SLIST_INIT(&m->m_pkthdr.tags);
  872 }
  873 
  874 /*
  875  * Set up the contents of a tag.  Note that this does not fill in the free
  876  * method; the caller is expected to do that.
  877  *
  878  * XXX probably should be called m_tag_init, but that was already taken.
  879  */
  880 static __inline void
  881 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
  882 {
  883 
  884         t->m_tag_id = type;
  885         t->m_tag_len = len;
  886         t->m_tag_cookie = cookie;
  887 }
  888 
  889 /*
  890  * Reclaim resources associated with a tag.
  891  */
  892 static __inline void
  893 m_tag_free(struct m_tag *t)
  894 {
  895 
  896         (*t->m_tag_free)(t);
  897 }
  898 
  899 /*
  900  * Return the first tag associated with an mbuf.
  901  */
  902 static __inline struct m_tag *
  903 m_tag_first(struct mbuf *m)
  904 {
  905 
  906         return (SLIST_FIRST(&m->m_pkthdr.tags));
  907 }
  908 
  909 /*
  910  * Return the next tag in the list of tags associated with an mbuf.
  911  */
  912 static __inline struct m_tag *
  913 m_tag_next(struct mbuf *m, struct m_tag *t)
  914 {
  915 
  916         return (SLIST_NEXT(t, m_tag_link));
  917 }
  918 
  919 /*
  920  * Prepend a tag to the list of tags associated with an mbuf.
  921  */
  922 static __inline void
  923 m_tag_prepend(struct mbuf *m, struct m_tag *t)
  924 {
  925 
  926         SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
  927 }
  928 
  929 /*
  930  * Unlink a tag from the list of tags associated with an mbuf.
  931  */
  932 static __inline void
  933 m_tag_unlink(struct mbuf *m, struct m_tag *t)
  934 {
  935 
  936         SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
  937 }
  938 
  939 /* These are for OpenBSD compatibility. */
  940 #define MTAG_ABI_COMPAT         0               /* compatibility ABI */
  941 
  942 static __inline struct m_tag *
  943 m_tag_get(int type, int length, int wait)
  944 {
  945         return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
  946 }
  947 
  948 static __inline struct m_tag *
  949 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
  950 {
  951         return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL :
  952             m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
  953 }
  954 
  955 #endif /* _KERNEL */
  956 
  957 #endif /* !_SYS_MBUF_H_ */

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