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: stable/7/sys/sys/mbuf.h 229755 2012-01-07 01:12:21Z yongari $
   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           0x00000001 /* has associated external storage */
  173 #define M_PKTHDR        0x00000002 /* start of record */
  174 #define M_EOR           0x00000004 /* end of record */
  175 #define M_RDONLY        0x00000008 /* associated data is marked read-only */
  176 #define M_PROTO1        0x00000010 /* protocol-specific */
  177 #define M_PROTO2        0x00000020 /* protocol-specific */
  178 #define M_PROTO3        0x00000040 /* protocol-specific */
  179 #define M_PROTO4        0x00000080 /* protocol-specific */
  180 #define M_PROTO5        0x00000100 /* protocol-specific */
  181 #define M_BCAST         0x00000200 /* send/received as link-level broadcast */
  182 #define M_MCAST         0x00000400 /* send/received as link-level multicast */
  183 #define M_FRAG          0x00000800 /* packet is a fragment of a larger packet */
  184 #define M_FIRSTFRAG     0x00001000 /* packet is first fragment */
  185 #define M_LASTFRAG      0x00002000 /* packet is last fragment */
  186 #define M_SKIP_FIREWALL 0x00004000 /* skip firewall processing */
  187 #define M_FREELIST      0x00008000 /* mbuf is on the free list */
  188 #define M_VLANTAG       0x00010000 /* ether_vtag is valid */
  189 #define M_PROMISC       0x00020000 /* packet was not for us */
  190 #define M_NOFREE        0x00040000 /* do not free mbuf, embedded in cluster */
  191 #define M_PROTO6        0x00080000 /* protocol-specific */
  192 #define M_PROTO7        0x00100000 /* protocol-specific */
  193 #define M_PROTO8        0x00200000 /* protocol-specific */
  194 /*
  195  * For RELENG_{6,7} steal these flags for limited multiple routing table
  196  * support. In RELENG_8 and beyond, use just one flag and a tag.
  197  */
  198 #define M_FIB           0xF0000000 /* steal some bits to store fib number. */
  199 
  200 #define M_NOTIFICATION  M_PROTO5    /* SCTP notification */
  201 
  202 /*
  203  * Flags to purge when crossing layers.
  204  */
  205 #define M_PROTOFLAGS \
  206     (M_PROTO1|M_PROTO2|M_PROTO3|M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8)
  207 
  208 /*
  209  * Flags preserved when copying m_pkthdr.
  210  */
  211 #define M_COPYFLAGS \
  212     (M_PKTHDR|M_EOR|M_RDONLY|M_PROTOFLAGS|M_SKIP_FIREWALL|M_BCAST|M_MCAST|\
  213      M_FRAG|M_FIRSTFRAG|M_LASTFRAG|M_VLANTAG|M_PROMISC|M_FIB)
  214 
  215 /*
  216  * External buffer types: identify ext_buf type.
  217  */
  218 #define EXT_CLUSTER     1       /* mbuf cluster */
  219 #define EXT_SFBUF       2       /* sendfile(2)'s sf_bufs */
  220 #define EXT_JUMBOP      3       /* jumbo cluster 4096 bytes */
  221 #define EXT_JUMBO9      4       /* jumbo cluster 9216 bytes */
  222 #define EXT_JUMBO16     5       /* jumbo cluster 16184 bytes */
  223 #define EXT_PACKET      6       /* mbuf+cluster from packet zone */
  224 #define EXT_MBUF        7       /* external mbuf reference (M_IOVEC) */
  225 #define EXT_NET_DRV     100     /* custom ext_buf provided by net driver(s) */
  226 #define EXT_MOD_TYPE    200     /* custom module's ext_buf type */
  227 #define EXT_DISPOSABLE  300     /* can throw this buffer away w/page flipping */
  228 #define EXT_EXTREF      400     /* has externally maintained ref_cnt ptr */
  229 
  230 /*
  231  * Flags indicating hw checksum support and sw checksum requirements.  This
  232  * field can be directly tested against if_data.ifi_hwassist.
  233  */
  234 #define CSUM_IP                 0x0001          /* will csum IP */
  235 #define CSUM_TCP                0x0002          /* will csum TCP */
  236 #define CSUM_UDP                0x0004          /* will csum UDP */
  237 #define CSUM_IP_FRAGS           0x0008          /* will csum IP fragments */
  238 #define CSUM_FRAGMENT           0x0010          /* will do IP fragmentation */
  239 #define CSUM_TSO                0x0020          /* will do TSO */
  240 #define CSUM_SCTP               0x0040          /* will csum SCTP */
  241 
  242 #define CSUM_IP_CHECKED         0x0100          /* did csum IP */
  243 #define CSUM_IP_VALID           0x0200          /*   ... the csum is valid */
  244 #define CSUM_DATA_VALID         0x0400          /* csum_data field is valid */
  245 #define CSUM_PSEUDO_HDR         0x0800          /* csum_data has pseudo hdr */
  246 #define CSUM_SCTP_VALID         0x1000          /* SCTP checksum is valid */
  247 
  248 #define CSUM_DELAY_DATA         (CSUM_TCP | CSUM_UDP)
  249 #define CSUM_DELAY_IP           (CSUM_IP)       /* XXX add ipv6 here too? */
  250 
  251 /*
  252  * mbuf types.
  253  */
  254 #define MT_NOTMBUF      0       /* USED INTERNALLY ONLY! Object is not mbuf */
  255 #define MT_DATA         1       /* dynamic (data) allocation */
  256 #define MT_HEADER       MT_DATA /* packet header, use M_PKTHDR instead */
  257 #define MT_SONAME       8       /* socket name */
  258 #define MT_CONTROL      14      /* extra-data protocol message */
  259 #define MT_OOBDATA      15      /* expedited data  */
  260 #define MT_NTYPES       16      /* number of mbuf types for mbtypes[] */
  261 
  262 #define MT_NOINIT       255     /* Not a type but a flag to allocate
  263                                    a non-initialized mbuf */
  264 
  265 #define MB_NOTAGS       0x1UL   /* no tags attached to mbuf */
  266 
  267 /*
  268  * General mbuf allocator statistics structure.
  269  *
  270  * Many of these statistics are no longer used; we instead track many
  271  * allocator statistics through UMA's built in statistics mechanism.
  272  */
  273 struct mbstat {
  274         u_long  m_mbufs;        /* XXX */
  275         u_long  m_mclusts;      /* XXX */
  276 
  277         u_long  m_drain;        /* times drained protocols for space */
  278         u_long  m_mcfail;       /* XXX: times m_copym failed */
  279         u_long  m_mpfail;       /* XXX: times m_pullup failed */
  280         u_long  m_msize;        /* length of an mbuf */
  281         u_long  m_mclbytes;     /* length of an mbuf cluster */
  282         u_long  m_minclsize;    /* min length of data to allocate a cluster */
  283         u_long  m_mlen;         /* length of data in an mbuf */
  284         u_long  m_mhlen;        /* length of data in a header mbuf */
  285 
  286         /* Number of mbtypes (gives # elems in mbtypes[] array) */
  287         short   m_numtypes;
  288 
  289         /* XXX: Sendfile stats should eventually move to their own struct */
  290         u_long  sf_iocnt;       /* times sendfile had to do disk I/O */
  291         u_long  sf_allocfail;   /* times sfbuf allocation failed */
  292         u_long  sf_allocwait;   /* times sfbuf allocation had to wait */
  293 };
  294 
  295 /*
  296  * Flags specifying how an allocation should be made.
  297  *
  298  * The flag to use is as follows:
  299  * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
  300  * - M_WAIT or M_WAITOK or M_TRYWAIT from wherever it is safe to block.
  301  *
  302  * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly and
  303  * if we cannot allocate immediately we may return NULL, whereas
  304  * M_WAIT/M_WAITOK/M_TRYWAIT means that if we cannot allocate resources we
  305  * will block until they are available, and thus never return NULL.
  306  *
  307  * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
  308  */
  309 #define MBTOM(how)      (how)
  310 #define M_DONTWAIT      M_NOWAIT
  311 #define M_TRYWAIT       M_WAITOK
  312 #define M_WAIT          M_WAITOK
  313 
  314 /*
  315  * String names of mbuf-related UMA(9) and malloc(9) types.  Exposed to
  316  * !_KERNEL so that monitoring tools can look up the zones with
  317  * libmemstat(3).
  318  */
  319 #define MBUF_MEM_NAME           "mbuf"
  320 #define MBUF_CLUSTER_MEM_NAME   "mbuf_cluster"
  321 #define MBUF_PACKET_MEM_NAME    "mbuf_packet"
  322 #define MBUF_JUMBOP_MEM_NAME    "mbuf_jumbo_pagesize"
  323 #define MBUF_JUMBO9_MEM_NAME    "mbuf_jumbo_9k"
  324 #define MBUF_JUMBO16_MEM_NAME   "mbuf_jumbo_16k"
  325 #define MBUF_TAG_MEM_NAME       "mbuf_tag"
  326 #define MBUF_EXTREFCNT_MEM_NAME "mbuf_ext_refcnt"
  327 
  328 #ifdef _KERNEL
  329 
  330 #ifdef WITNESS
  331 #define MBUF_CHECKSLEEP(how) do {                                       \
  332         if (how == M_WAITOK)                                            \
  333                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,         \
  334                     "Sleeping in \"%s\"", __func__);                    \
  335 } while (0)
  336 #else
  337 #define MBUF_CHECKSLEEP(how)
  338 #endif
  339 
  340 /*
  341  * Network buffer allocation API
  342  *
  343  * The rest of it is defined in kern/kern_mbuf.c
  344  */
  345 
  346 extern uma_zone_t       zone_mbuf;
  347 extern uma_zone_t       zone_clust;
  348 extern uma_zone_t       zone_pack;
  349 extern uma_zone_t       zone_jumbop;
  350 extern uma_zone_t       zone_jumbo9;
  351 extern uma_zone_t       zone_jumbo16;
  352 extern uma_zone_t       zone_ext_refcnt;
  353 
  354 static __inline struct mbuf     *m_getcl(int how, short type, int flags);
  355 static __inline struct mbuf     *m_get(int how, short type);
  356 static __inline struct mbuf     *m_gethdr(int how, short type);
  357 static __inline struct mbuf     *m_getjcl(int how, short type, int flags,
  358                                     int size);
  359 static __inline struct mbuf     *m_getclr(int how, short type); /* XXX */
  360 static __inline struct mbuf     *m_free(struct mbuf *m);
  361 static __inline void             m_clget(struct mbuf *m, int how);
  362 static __inline void            *m_cljget(struct mbuf *m, int how, int size);
  363 static __inline void             m_chtype(struct mbuf *m, short new_type);
  364 void                             mb_free_ext(struct mbuf *);
  365 static __inline struct mbuf     *m_last(struct mbuf *m);
  366 
  367 static __inline int
  368 m_gettype(int size)
  369 {
  370         int type;
  371         
  372         switch (size) {
  373         case MSIZE:
  374                 type = EXT_MBUF;
  375                 break;
  376         case MCLBYTES:
  377                 type = EXT_CLUSTER;
  378                 break;
  379 #if MJUMPAGESIZE != MCLBYTES
  380         case MJUMPAGESIZE:
  381                 type = EXT_JUMBOP;
  382                 break;
  383 #endif
  384         case MJUM9BYTES:
  385                 type = EXT_JUMBO9;
  386                 break;
  387         case MJUM16BYTES:
  388                 type = EXT_JUMBO16;
  389                 break;
  390         default:
  391                 panic("%s: m_getjcl: invalid cluster size", __func__);
  392         }
  393 
  394         return (type);
  395 }
  396 
  397 static __inline uma_zone_t
  398 m_getzone(int size)
  399 {
  400         uma_zone_t zone;
  401         
  402         switch (size) {
  403         case MSIZE:
  404                 zone = zone_mbuf;
  405                 break;
  406         case MCLBYTES:
  407                 zone = zone_clust;
  408                 break;
  409 #if MJUMPAGESIZE != MCLBYTES
  410         case MJUMPAGESIZE:
  411                 zone = zone_jumbop;
  412                 break;
  413 #endif
  414         case MJUM9BYTES:
  415                 zone = zone_jumbo9;
  416                 break;
  417         case MJUM16BYTES:
  418                 zone = zone_jumbo16;
  419                 break;
  420         default:
  421                 panic("%s: m_getjcl: invalid cluster type", __func__);
  422         }
  423 
  424         return (zone);
  425 }
  426 
  427 static __inline struct mbuf *
  428 m_get(int how, short type)
  429 {
  430         struct mb_args args;
  431 
  432         args.flags = 0;
  433         args.type = type;
  434         return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
  435 }
  436 
  437 /*
  438  * XXX This should be deprecated, very little use.
  439  */
  440 static __inline struct mbuf *
  441 m_getclr(int how, short type)
  442 {
  443         struct mbuf *m;
  444         struct mb_args args;
  445 
  446         args.flags = 0;
  447         args.type = type;
  448         m = uma_zalloc_arg(zone_mbuf, &args, how);
  449         if (m != NULL)
  450                 bzero(m->m_data, MLEN);
  451         return (m);
  452 }
  453 
  454 static __inline struct mbuf *
  455 m_gethdr(int how, short type)
  456 {
  457         struct mb_args args;
  458 
  459         args.flags = M_PKTHDR;
  460         args.type = type;
  461         return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
  462 }
  463 
  464 static __inline struct mbuf *
  465 m_getcl(int how, short type, int flags)
  466 {
  467         struct mb_args args;
  468 
  469         args.flags = flags;
  470         args.type = type;
  471         return ((struct mbuf *)(uma_zalloc_arg(zone_pack, &args, how)));
  472 }
  473 
  474 /*
  475  * m_getjcl() returns an mbuf with a cluster of the specified size attached.
  476  * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
  477  *
  478  * XXX: This is rather large, should be real function maybe.
  479  */
  480 static __inline struct mbuf *
  481 m_getjcl(int how, short type, int flags, int size)
  482 {
  483         struct mb_args args;
  484         struct mbuf *m, *n;
  485         uma_zone_t zone;
  486 
  487         if (size == MCLBYTES)
  488                 return m_getcl(how, type, flags);
  489 
  490         args.flags = flags;
  491         args.type = type;
  492 
  493         m = uma_zalloc_arg(zone_mbuf, &args, how);
  494         if (m == NULL)
  495                 return (NULL);
  496 
  497         zone = m_getzone(size);
  498         n = uma_zalloc_arg(zone, m, how);
  499         if (n == NULL) {
  500                 uma_zfree(zone_mbuf, m);
  501                 return (NULL);
  502         }
  503         return (m);
  504 }
  505 
  506 static __inline void
  507 m_free_fast(struct mbuf *m)
  508 {
  509         KASSERT(SLIST_EMPTY(&m->m_pkthdr.tags), ("doing fast free of mbuf with tags"));
  510 
  511         uma_zfree_arg(zone_mbuf, m, (void *)MB_NOTAGS);
  512 }
  513 
  514 static __inline struct mbuf *
  515 m_free(struct mbuf *m)
  516 {
  517         struct mbuf *n = m->m_next;
  518 
  519         if (m->m_flags & M_EXT)
  520                 mb_free_ext(m);
  521         else if ((m->m_flags & M_NOFREE) == 0)
  522                 uma_zfree(zone_mbuf, m);
  523         return (n);
  524 }
  525 
  526 static __inline void
  527 m_clget(struct mbuf *m, int how)
  528 {
  529 
  530         if (m->m_flags & M_EXT)
  531                 printf("%s: %p mbuf already has cluster\n", __func__, m);
  532         m->m_ext.ext_buf = (char *)NULL;
  533         uma_zalloc_arg(zone_clust, m, how);
  534         /*
  535          * On a cluster allocation failure, drain the packet zone and retry,
  536          * we might be able to loosen a few clusters up on the drain.
  537          */
  538         if ((how & M_NOWAIT) && (m->m_ext.ext_buf == NULL)) {
  539                 zone_drain(zone_pack);
  540                 uma_zalloc_arg(zone_clust, m, how);
  541         }
  542 }
  543 
  544 /*
  545  * m_cljget() is different from m_clget() as it can allocate clusters without
  546  * attaching them to an mbuf.  In that case the return value is the pointer
  547  * to the cluster of the requested size.  If an mbuf was specified, it gets
  548  * the cluster attached to it and the return value can be safely ignored.
  549  * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
  550  */
  551 static __inline void *
  552 m_cljget(struct mbuf *m, int how, int size)
  553 {
  554         uma_zone_t zone;
  555 
  556         if (m && m->m_flags & M_EXT)
  557                 printf("%s: %p mbuf already has cluster\n", __func__, m);
  558         if (m != NULL)
  559                 m->m_ext.ext_buf = NULL;
  560 
  561         zone = m_getzone(size);
  562         return (uma_zalloc_arg(zone, m, how));
  563 }
  564 
  565 static __inline void
  566 m_cljset(struct mbuf *m, void *cl, int type)
  567 {
  568         uma_zone_t zone;
  569         int size;
  570         
  571         switch (type) {
  572         case EXT_CLUSTER:
  573                 size = MCLBYTES;
  574                 zone = zone_clust;
  575                 break;
  576 #if MJUMPAGESIZE != MCLBYTES
  577         case EXT_JUMBOP:
  578                 size = MJUMPAGESIZE;
  579                 zone = zone_jumbop;
  580                 break;
  581 #endif
  582         case EXT_JUMBO9:
  583                 size = MJUM9BYTES;
  584                 zone = zone_jumbo9;
  585                 break;
  586         case EXT_JUMBO16:
  587                 size = MJUM16BYTES;
  588                 zone = zone_jumbo16;
  589                 break;
  590         default:
  591                 panic("unknown cluster type");
  592                 break;
  593         }
  594 
  595         m->m_data = m->m_ext.ext_buf = cl;
  596         m->m_ext.ext_free = m->m_ext.ext_args = NULL;
  597         m->m_ext.ext_size = size;
  598         m->m_ext.ext_type = type;
  599         m->m_ext.ref_cnt = uma_find_refcnt(zone, cl);
  600         m->m_flags |= M_EXT;
  601 
  602 }
  603 
  604 static __inline void
  605 m_chtype(struct mbuf *m, short new_type)
  606 {
  607 
  608         m->m_type = new_type;
  609 }
  610 
  611 static __inline struct mbuf *
  612 m_last(struct mbuf *m)
  613 {
  614 
  615         while (m->m_next)
  616                 m = m->m_next;
  617         return (m);
  618 }
  619 
  620 /*
  621  * mbuf, cluster, and external object allocation macros (for compatibility
  622  * purposes).
  623  */
  624 #define M_MOVE_PKTHDR(to, from) m_move_pkthdr((to), (from))
  625 #define MGET(m, how, type)      ((m) = m_get((how), (type)))
  626 #define MGETHDR(m, how, type)   ((m) = m_gethdr((how), (type)))
  627 #define MCLGET(m, how)          m_clget((m), (how))
  628 #define MEXTADD(m, buf, size, free, args, flags, type)                  \
  629     m_extadd((m), (caddr_t)(buf), (size), (free), (args), (flags), (type))
  630 #define m_getm(m, len, how, type)                                       \
  631     m_getm2((m), (len), (how), (type), M_PKTHDR)
  632 
  633 /*
  634  * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
  635  * be both the local data payload, or an external buffer area, depending on
  636  * whether M_EXT is set).
  637  */
  638 #define M_WRITABLE(m)   (!((m)->m_flags & M_RDONLY) &&                  \
  639                          (!(((m)->m_flags & M_EXT)) ||                  \
  640                          (*((m)->m_ext.ref_cnt) == 1)) )                \
  641 
  642 /* Check if the supplied mbuf has a packet header, or else panic. */
  643 #define M_ASSERTPKTHDR(m)                                               \
  644         KASSERT(m != NULL && m->m_flags & M_PKTHDR,                     \
  645             ("%s: no mbuf packet header!", __func__))
  646 
  647 /*
  648  * Ensure that the supplied mbuf is a valid, non-free mbuf.
  649  *
  650  * XXX: Broken at the moment.  Need some UMA magic to make it work again.
  651  */
  652 #define M_ASSERTVALID(m)                                                \
  653         KASSERT((((struct mbuf *)m)->m_flags & 0) == 0,                 \
  654             ("%s: attempted use of a free mbuf!", __func__))
  655 
  656 /*
  657  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place an
  658  * object of the specified size at the end of the mbuf, longword aligned.
  659  */
  660 #define M_ALIGN(m, len) do {                                            \
  661         KASSERT(!((m)->m_flags & (M_PKTHDR|M_EXT)),                     \
  662                 ("%s: M_ALIGN not normal mbuf", __func__));             \
  663         KASSERT((m)->m_data == (m)->m_dat,                              \
  664                 ("%s: M_ALIGN not a virgin mbuf", __func__));           \
  665         (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1);            \
  666 } while (0)
  667 
  668 /*
  669  * As above, for mbufs allocated with m_gethdr/MGETHDR or initialized by
  670  * M_DUP/MOVE_PKTHDR.
  671  */
  672 #define MH_ALIGN(m, len) do {                                           \
  673         KASSERT((m)->m_flags & M_PKTHDR && !((m)->m_flags & M_EXT),     \
  674                 ("%s: MH_ALIGN not PKTHDR mbuf", __func__));            \
  675         KASSERT((m)->m_data == (m)->m_pktdat,                           \
  676                 ("%s: MH_ALIGN not a virgin mbuf", __func__));          \
  677         (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1);           \
  678 } while (0)
  679 
  680 /*
  681  * Compute the amount of space available before the current start of data in
  682  * an mbuf.
  683  *
  684  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  685  * of checking writability of the mbuf data area rests solely with the caller.
  686  */
  687 #define M_LEADINGSPACE(m)                                               \
  688         ((m)->m_flags & M_EXT ?                                         \
  689             (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0):     \
  690             (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat :     \
  691             (m)->m_data - (m)->m_dat)
  692 
  693 /*
  694  * Compute the amount of space available after the end of data in an mbuf.
  695  *
  696  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  697  * of checking writability of the mbuf data area rests solely with the caller.
  698  */
  699 #define M_TRAILINGSPACE(m)                                              \
  700         ((m)->m_flags & M_EXT ?                                         \
  701             (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size   \
  702                 - ((m)->m_data + (m)->m_len) : 0) :                     \
  703             &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
  704 
  705 /*
  706  * Arrange to prepend space of size plen to mbuf m.  If a new mbuf must be
  707  * allocated, how specifies whether to wait.  If the allocation fails, the
  708  * original mbuf chain is freed and m is set to NULL.
  709  */
  710 #define M_PREPEND(m, plen, how) do {                                    \
  711         struct mbuf **_mmp = &(m);                                      \
  712         struct mbuf *_mm = *_mmp;                                       \
  713         int _mplen = (plen);                                            \
  714         int __mhow = (how);                                             \
  715                                                                         \
  716         MBUF_CHECKSLEEP(how);                                           \
  717         if (M_LEADINGSPACE(_mm) >= _mplen) {                            \
  718                 _mm->m_data -= _mplen;                                  \
  719                 _mm->m_len += _mplen;                                   \
  720         } else                                                          \
  721                 _mm = m_prepend(_mm, _mplen, __mhow);                   \
  722         if (_mm != NULL && _mm->m_flags & M_PKTHDR)                     \
  723                 _mm->m_pkthdr.len += _mplen;                            \
  724         *_mmp = _mm;                                                    \
  725 } while (0)
  726 
  727 /*
  728  * Change mbuf to new type.  This is a relatively expensive operation and
  729  * should be avoided.
  730  */
  731 #define MCHTYPE(m, t)   m_chtype((m), (t))
  732 
  733 /* Length to m_copy to copy all. */
  734 #define M_COPYALL       1000000000
  735 
  736 /* Compatibility with 4.3. */
  737 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
  738 
  739 extern int              max_datalen;    /* MHLEN - max_hdr */
  740 extern int              max_hdr;        /* Largest link + protocol header */
  741 extern int              max_linkhdr;    /* Largest link-level header */
  742 extern int              max_protohdr;   /* Largest protocol header */
  743 extern struct mbstat    mbstat;         /* General mbuf stats/infos */
  744 extern int              nmbclusters;    /* Maximum number of clusters */
  745 
  746 struct uio;
  747 
  748 void             m_adj(struct mbuf *, int);
  749 void             m_align(struct mbuf *, int);
  750 int              m_apply(struct mbuf *, int, int,
  751                     int (*)(void *, void *, u_int), void *);
  752 int              m_append(struct mbuf *, int, c_caddr_t);
  753 void             m_cat(struct mbuf *, struct mbuf *);
  754 void             m_extadd(struct mbuf *, caddr_t, u_int,
  755                     void (*)(void *, void *), void *, int, int);
  756 struct mbuf     *m_collapse(struct mbuf *, int, int);
  757 void             m_copyback(struct mbuf *, int, int, c_caddr_t);
  758 void             m_copydata(const struct mbuf *, int, int, caddr_t);
  759 struct mbuf     *m_copym(struct mbuf *, int, int, int);
  760 struct mbuf     *m_copymdata(struct mbuf *, struct mbuf *,
  761                     int, int, int, int);
  762 struct mbuf     *m_copypacket(struct mbuf *, int);
  763 void             m_copy_pkthdr(struct mbuf *, struct mbuf *);
  764 struct mbuf     *m_copyup(struct mbuf *n, int len, int dstoff);
  765 struct mbuf     *m_defrag(struct mbuf *, int);
  766 void             m_demote(struct mbuf *, int);
  767 struct mbuf     *m_devget(char *, int, int, struct ifnet *,
  768                     void (*)(char *, caddr_t, u_int));
  769 struct mbuf     *m_dup(struct mbuf *, int);
  770 int              m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
  771 u_int            m_fixhdr(struct mbuf *);
  772 struct mbuf     *m_fragment(struct mbuf *, int, int);
  773 void             m_freem(struct mbuf *);
  774 struct mbuf     *m_getm2(struct mbuf *, int, int, short, int);
  775 struct mbuf     *m_getptr(struct mbuf *, int, int *);
  776 u_int            m_length(struct mbuf *, struct mbuf **);
  777 void             m_move_pkthdr(struct mbuf *, struct mbuf *);
  778 struct mbuf     *m_prepend(struct mbuf *, int, int);
  779 void             m_print(const struct mbuf *, int);
  780 struct mbuf     *m_pulldown(struct mbuf *, int, int, int *);
  781 struct mbuf     *m_pullup(struct mbuf *, int);
  782 int             m_sanity(struct mbuf *, int);
  783 struct mbuf     *m_split(struct mbuf *, int, int);
  784 struct mbuf     *m_uiotombuf(struct uio *, int, int, int, int);
  785 struct mbuf     *m_unshare(struct mbuf *, int how);
  786 
  787 /*-
  788  * Network packets may have annotations attached by affixing a list of
  789  * "packet tags" to the pkthdr structure.  Packet tags are dynamically
  790  * allocated semi-opaque data structures that have a fixed header
  791  * (struct m_tag) that specifies the size of the memory block and a
  792  * <cookie,type> pair that identifies it.  The cookie is a 32-bit unique
  793  * unsigned value used to identify a module or ABI.  By convention this value
  794  * is chosen as the date+time that the module is created, expressed as the
  795  * number of seconds since the epoch (e.g., using date -u +'%s').  The type
  796  * value is an ABI/module-specific value that identifies a particular
  797  * annotation and is private to the module.  For compatibility with systems
  798  * like OpenBSD that define packet tags w/o an ABI/module cookie, the value
  799  * PACKET_ABI_COMPAT is used to implement m_tag_get and m_tag_find
  800  * compatibility shim functions and several tag types are defined below.
  801  * Users that do not require compatibility should use a private cookie value
  802  * so that packet tag-related definitions can be maintained privately.
  803  *
  804  * Note that the packet tag returned by m_tag_alloc has the default memory
  805  * alignment implemented by malloc.  To reference private data one can use a
  806  * construct like:
  807  *
  808  *      struct m_tag *mtag = m_tag_alloc(...);
  809  *      struct foo *p = (struct foo *)(mtag+1);
  810  *
  811  * if the alignment of struct m_tag is sufficient for referencing members of
  812  * struct foo.  Otherwise it is necessary to embed struct m_tag within the
  813  * private data structure to insure proper alignment; e.g.,
  814  *
  815  *      struct foo {
  816  *              struct m_tag    tag;
  817  *              ...
  818  *      };
  819  *      struct foo *p = (struct foo *) m_tag_alloc(...);
  820  *      struct m_tag *mtag = &p->tag;
  821  */
  822 
  823 /*
  824  * Persistent tags stay with an mbuf until the mbuf is reclaimed.  Otherwise
  825  * tags are expected to ``vanish'' when they pass through a network
  826  * interface.  For most interfaces this happens normally as the tags are
  827  * reclaimed when the mbuf is free'd.  However in some special cases
  828  * reclaiming must be done manually.  An example is packets that pass through
  829  * the loopback interface.  Also, one must be careful to do this when
  830  * ``turning around'' packets (e.g., icmp_reflect).
  831  *
  832  * To mark a tag persistent bit-or this flag in when defining the tag id.
  833  * The tag will then be treated as described above.
  834  */
  835 #define MTAG_PERSISTENT                         0x800
  836 
  837 #define PACKET_TAG_NONE                         0  /* Nadda */
  838 
  839 /* Packet tags for use with PACKET_ABI_COMPAT. */
  840 #define PACKET_TAG_IPSEC_IN_DONE                1  /* IPsec applied, in */
  841 #define PACKET_TAG_IPSEC_OUT_DONE               2  /* IPsec applied, out */
  842 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE         3  /* NIC IPsec crypto done */
  843 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED      4  /* NIC IPsec crypto req'ed */
  844 #define PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO     5  /* NIC notifies IPsec */
  845 #define PACKET_TAG_IPSEC_PENDING_TDB            6  /* Reminder to do IPsec */
  846 #define PACKET_TAG_BRIDGE                       7  /* Bridge processing done */
  847 #define PACKET_TAG_GIF                          8  /* GIF processing done */
  848 #define PACKET_TAG_GRE                          9  /* GRE processing done */
  849 #define PACKET_TAG_IN_PACKET_CHECKSUM           10 /* NIC checksumming done */
  850 #define PACKET_TAG_ENCAP                        11 /* Encap.  processing */
  851 #define PACKET_TAG_IPSEC_SOCKET                 12 /* IPSEC socket ref */
  852 #define PACKET_TAG_IPSEC_HISTORY                13 /* IPSEC history */
  853 #define PACKET_TAG_IPV6_INPUT                   14 /* IPV6 input processing */
  854 #define PACKET_TAG_DUMMYNET                     15 /* dummynet info */
  855 #define PACKET_TAG_DIVERT                       17 /* divert info */
  856 #define PACKET_TAG_IPFORWARD                    18 /* ipforward info */
  857 #define PACKET_TAG_MACLABEL     (19 | MTAG_PERSISTENT) /* MAC label */
  858 #define PACKET_TAG_PF                           21 /* PF + ALTQ information */
  859 #define PACKET_TAG_RTSOCKFAM                    25 /* rtsock sa family */
  860 #define PACKET_TAG_IPOPTIONS                    27 /* Saved IP options */
  861 #define PACKET_TAG_CARP                         28 /* CARP info */
  862 
  863 /* Specific cookies and tags. */
  864 
  865 /* Packet tag routines. */
  866 struct m_tag    *m_tag_alloc(u_int32_t, int, int, int);
  867 void             m_tag_delete(struct mbuf *, struct m_tag *);
  868 void             m_tag_delete_chain(struct mbuf *, struct m_tag *);
  869 void             m_tag_free_default(struct m_tag *);
  870 struct m_tag    *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
  871 struct m_tag    *m_tag_copy(struct m_tag *, int);
  872 int              m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
  873 void             m_tag_delete_nonpersistent(struct mbuf *);
  874 
  875 /*
  876  * Initialize the list of tags associated with an mbuf.
  877  */
  878 static __inline void
  879 m_tag_init(struct mbuf *m)
  880 {
  881 
  882         SLIST_INIT(&m->m_pkthdr.tags);
  883 }
  884 
  885 /*
  886  * Set up the contents of a tag.  Note that this does not fill in the free
  887  * method; the caller is expected to do that.
  888  *
  889  * XXX probably should be called m_tag_init, but that was already taken.
  890  */
  891 static __inline void
  892 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
  893 {
  894 
  895         t->m_tag_id = type;
  896         t->m_tag_len = len;
  897         t->m_tag_cookie = cookie;
  898 }
  899 
  900 /*
  901  * Reclaim resources associated with a tag.
  902  */
  903 static __inline void
  904 m_tag_free(struct m_tag *t)
  905 {
  906 
  907         (*t->m_tag_free)(t);
  908 }
  909 
  910 /*
  911  * Return the first tag associated with an mbuf.
  912  */
  913 static __inline struct m_tag *
  914 m_tag_first(struct mbuf *m)
  915 {
  916 
  917         return (SLIST_FIRST(&m->m_pkthdr.tags));
  918 }
  919 
  920 /*
  921  * Return the next tag in the list of tags associated with an mbuf.
  922  */
  923 static __inline struct m_tag *
  924 m_tag_next(struct mbuf *m, struct m_tag *t)
  925 {
  926 
  927         return (SLIST_NEXT(t, m_tag_link));
  928 }
  929 
  930 /*
  931  * Prepend a tag to the list of tags associated with an mbuf.
  932  */
  933 static __inline void
  934 m_tag_prepend(struct mbuf *m, struct m_tag *t)
  935 {
  936 
  937         SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
  938 }
  939 
  940 /*
  941  * Unlink a tag from the list of tags associated with an mbuf.
  942  */
  943 static __inline void
  944 m_tag_unlink(struct mbuf *m, struct m_tag *t)
  945 {
  946 
  947         SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
  948 }
  949 
  950 /* These are for OpenBSD compatibility. */
  951 #define MTAG_ABI_COMPAT         0               /* compatibility ABI */
  952 
  953 static __inline struct m_tag *
  954 m_tag_get(int type, int length, int wait)
  955 {
  956         return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
  957 }
  958 
  959 static __inline struct m_tag *
  960 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
  961 {
  962         return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL :
  963             m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
  964 }
  965 
  966 /* XXX temporary FIB methods probably eventually use tags.*/
  967 #define M_FIBSHIFT    28
  968 #define M_FIBMASK       0x0F
  969 
  970 /* get the fib from an mbuf and if it is not set, return the default */
  971 #define M_GETFIB(_m) \
  972     ((((_m)->m_flags & M_FIB) >> M_FIBSHIFT) & M_FIBMASK)
  973 
  974 #define M_SETFIB(_m, _fib) do {                                         \
  975         _m->m_flags &= ~M_FIB;                                          \
  976         _m->m_flags |= (((_fib) << M_FIBSHIFT) & M_FIB);  \
  977 } while (0) 
  978 
  979 #endif /* _KERNEL */
  980 
  981 #endif /* !_SYS_MBUF_H_ */

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