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: releng/8.0/sys/sys/mbuf.h 194667 2009-06-22 22:20:38Z andre $
   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  * Macro for type conversion: convert mbuf pointer to data pointer of correct
   64  * type:
   65  *
   66  * mtod(m, t)   -- Convert mbuf pointer to data pointer of correct type.
   67  */
   68 #define mtod(m, t)      ((t)((m)->m_data))
   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         uint32_t         flowid;        /* packet's 4-tuple system 
  119                                          * flow identifier
  120                                          */
  121         /* variables for hardware checksum */
  122         int              csum_flags;    /* flags regarding checksum */
  123         int              csum_data;     /* data field used by csum routines */
  124         u_int16_t        tso_segsz;     /* TSO segment size */
  125         union {
  126                 u_int16_t vt_vtag;      /* Ethernet 802.1p+q vlan tag */
  127                 u_int16_t vt_nrecs;     /* # of IGMPv3 records in this chain */
  128         } PH_vt;
  129         SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
  130 };
  131 #define ether_vtag      PH_vt.vt_vtag
  132 
  133 /*
  134  * Description of external storage mapped into mbuf; valid only if M_EXT is
  135  * set.
  136  */
  137 struct m_ext {
  138         caddr_t          ext_buf;       /* start of buffer */
  139         void            (*ext_free)     /* free routine if not the usual */
  140                             (void *, void *);
  141         void            *ext_arg1;      /* optional argument pointer */
  142         void            *ext_arg2;      /* optional argument pointer */
  143         u_int            ext_size;      /* size of buffer, for ext_free */
  144         volatile u_int  *ref_cnt;       /* pointer to ref count info */
  145         int              ext_type;      /* type of external storage */
  146 };
  147 
  148 /*
  149  * The core of the mbuf object along with some shortcut defines for practical
  150  * purposes.
  151  */
  152 struct mbuf {
  153         struct m_hdr    m_hdr;
  154         union {
  155                 struct {
  156                         struct pkthdr   MH_pkthdr;      /* M_PKTHDR set */
  157                         union {
  158                                 struct m_ext    MH_ext; /* M_EXT set */
  159                                 char            MH_databuf[MHLEN];
  160                         } MH_dat;
  161                 } MH;
  162                 char    M_databuf[MLEN];                /* !M_PKTHDR, !M_EXT */
  163         } M_dat;
  164 };
  165 #define m_next          m_hdr.mh_next
  166 #define m_len           m_hdr.mh_len
  167 #define m_data          m_hdr.mh_data
  168 #define m_type          m_hdr.mh_type
  169 #define m_flags         m_hdr.mh_flags
  170 #define m_nextpkt       m_hdr.mh_nextpkt
  171 #define m_act           m_nextpkt
  172 #define m_pkthdr        M_dat.MH.MH_pkthdr
  173 #define m_ext           M_dat.MH.MH_dat.MH_ext
  174 #define m_pktdat        M_dat.MH.MH_dat.MH_databuf
  175 #define m_dat           M_dat.M_databuf
  176 
  177 /*
  178  * mbuf flags.
  179  */
  180 #define M_EXT           0x00000001 /* has associated external storage */
  181 #define M_PKTHDR        0x00000002 /* start of record */
  182 #define M_EOR           0x00000004 /* end of record */
  183 #define M_RDONLY        0x00000008 /* associated data is marked read-only */
  184 #define M_PROTO1        0x00000010 /* protocol-specific */
  185 #define M_PROTO2        0x00000020 /* protocol-specific */
  186 #define M_PROTO3        0x00000040 /* protocol-specific */
  187 #define M_PROTO4        0x00000080 /* protocol-specific */
  188 #define M_PROTO5        0x00000100 /* protocol-specific */
  189 #define M_BCAST         0x00000200 /* send/received as link-level broadcast */
  190 #define M_MCAST         0x00000400 /* send/received as link-level multicast */
  191 #define M_FRAG          0x00000800 /* packet is a fragment of a larger packet */
  192 #define M_FIRSTFRAG     0x00001000 /* packet is first fragment */
  193 #define M_LASTFRAG      0x00002000 /* packet is last fragment */
  194 #define M_SKIP_FIREWALL 0x00004000 /* skip firewall processing */
  195 #define M_FREELIST      0x00008000 /* mbuf is on the free list */
  196 #define M_VLANTAG       0x00010000 /* ether_vtag is valid */
  197 #define M_PROMISC       0x00020000 /* packet was not for us */
  198 #define M_NOFREE        0x00040000 /* do not free mbuf, embedded in cluster */
  199 #define M_PROTO6        0x00080000 /* protocol-specific */
  200 #define M_PROTO7        0x00100000 /* protocol-specific */
  201 #define M_PROTO8        0x00200000 /* protocol-specific */
  202 #define M_FLOWID        0x00400000 /* flowid is valid */
  203 /*
  204  * For RELENG_{6,7} steal these flags for limited multiple routing table
  205  * support. In RELENG_8 and beyond, use just one flag and a tag.
  206  */
  207 #define M_FIB           0xF0000000 /* steal some bits to store fib number. */
  208 
  209 #define M_NOTIFICATION  M_PROTO5    /* SCTP notification */
  210 
  211 /*
  212  * Flags to purge when crossing layers.
  213  */
  214 #define M_PROTOFLAGS \
  215     (M_PROTO1|M_PROTO2|M_PROTO3|M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8)
  216 
  217 /*
  218  * Flags preserved when copying m_pkthdr.
  219  */
  220 #define M_COPYFLAGS \
  221     (M_PKTHDR|M_EOR|M_RDONLY|M_PROTOFLAGS|M_SKIP_FIREWALL|M_BCAST|M_MCAST|\
  222      M_FRAG|M_FIRSTFRAG|M_LASTFRAG|M_VLANTAG|M_PROMISC|M_FIB)
  223 
  224 /*
  225  * External buffer types: identify ext_buf type.
  226  */
  227 #define EXT_CLUSTER     1       /* mbuf cluster */
  228 #define EXT_SFBUF       2       /* sendfile(2)'s sf_bufs */
  229 #define EXT_JUMBOP      3       /* jumbo cluster 4096 bytes */
  230 #define EXT_JUMBO9      4       /* jumbo cluster 9216 bytes */
  231 #define EXT_JUMBO16     5       /* jumbo cluster 16184 bytes */
  232 #define EXT_PACKET      6       /* mbuf+cluster from packet zone */
  233 #define EXT_MBUF        7       /* external mbuf reference (M_IOVEC) */
  234 #define EXT_NET_DRV     100     /* custom ext_buf provided by net driver(s) */
  235 #define EXT_MOD_TYPE    200     /* custom module's ext_buf type */
  236 #define EXT_DISPOSABLE  300     /* can throw this buffer away w/page flipping */
  237 #define EXT_EXTREF      400     /* has externally maintained ref_cnt ptr */
  238 
  239 /*
  240  * Flags indicating hw checksum support and sw checksum requirements.  This
  241  * field can be directly tested against if_data.ifi_hwassist.
  242  */
  243 #define CSUM_IP                 0x0001          /* will csum IP */
  244 #define CSUM_TCP                0x0002          /* will csum TCP */
  245 #define CSUM_UDP                0x0004          /* will csum UDP */
  246 #define CSUM_IP_FRAGS           0x0008          /* will csum IP fragments */
  247 #define CSUM_FRAGMENT           0x0010          /* will do IP fragmentation */
  248 #define CSUM_TSO                0x0020          /* will do TSO */
  249 #define CSUM_SCTP               0x0040          /* will csum SCTP */
  250 
  251 #define CSUM_IP_CHECKED         0x0100          /* did csum IP */
  252 #define CSUM_IP_VALID           0x0200          /*   ... the csum is valid */
  253 #define CSUM_DATA_VALID         0x0400          /* csum_data field is valid */
  254 #define CSUM_PSEUDO_HDR         0x0800          /* csum_data has pseudo hdr */
  255 #define CSUM_SCTP_VALID         0x1000          /* SCTP checksum is valid */
  256 
  257 #define CSUM_DELAY_DATA         (CSUM_TCP | CSUM_UDP)
  258 #define CSUM_DELAY_IP           (CSUM_IP)       /* XXX add ipv6 here too? */
  259 
  260 /*
  261  * mbuf types.
  262  */
  263 #define MT_NOTMBUF      0       /* USED INTERNALLY ONLY! Object is not mbuf */
  264 #define MT_DATA         1       /* dynamic (data) allocation */
  265 #define MT_HEADER       MT_DATA /* packet header, use M_PKTHDR instead */
  266 #define MT_SONAME       8       /* socket name */
  267 #define MT_CONTROL      14      /* extra-data protocol message */
  268 #define MT_OOBDATA      15      /* expedited data  */
  269 #define MT_NTYPES       16      /* number of mbuf types for mbtypes[] */
  270 
  271 #define MT_NOINIT       255     /* Not a type but a flag to allocate
  272                                    a non-initialized mbuf */
  273 
  274 #define MB_NOTAGS       0x1UL   /* no tags attached to mbuf */
  275 
  276 /*
  277  * General mbuf allocator statistics structure.
  278  *
  279  * Many of these statistics are no longer used; we instead track many
  280  * allocator statistics through UMA's built in statistics mechanism.
  281  */
  282 struct mbstat {
  283         u_long  m_mbufs;        /* XXX */
  284         u_long  m_mclusts;      /* XXX */
  285 
  286         u_long  m_drain;        /* times drained protocols for space */
  287         u_long  m_mcfail;       /* XXX: times m_copym failed */
  288         u_long  m_mpfail;       /* XXX: times m_pullup failed */
  289         u_long  m_msize;        /* length of an mbuf */
  290         u_long  m_mclbytes;     /* length of an mbuf cluster */
  291         u_long  m_minclsize;    /* min length of data to allocate a cluster */
  292         u_long  m_mlen;         /* length of data in an mbuf */
  293         u_long  m_mhlen;        /* length of data in a header mbuf */
  294 
  295         /* Number of mbtypes (gives # elems in mbtypes[] array) */
  296         short   m_numtypes;
  297 
  298         /* XXX: Sendfile stats should eventually move to their own struct */
  299         u_long  sf_iocnt;       /* times sendfile had to do disk I/O */
  300         u_long  sf_allocfail;   /* times sfbuf allocation failed */
  301         u_long  sf_allocwait;   /* times sfbuf allocation had to wait */
  302 };
  303 
  304 /*
  305  * Flags specifying how an allocation should be made.
  306  *
  307  * The flag to use is as follows:
  308  * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
  309  * - M_WAIT or M_WAITOK from wherever it is safe to block.
  310  *
  311  * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly and
  312  * if we cannot allocate immediately we may return NULL, whereas
  313  * M_WAIT/M_WAITOK means that if we cannot allocate resources we
  314  * will block until they are available, and thus never return NULL.
  315  *
  316  * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
  317  */
  318 #define MBTOM(how)      (how)
  319 #define M_DONTWAIT      M_NOWAIT
  320 #define M_TRYWAIT       M_WAITOK
  321 #define M_WAIT          M_WAITOK
  322 
  323 /*
  324  * String names of mbuf-related UMA(9) and malloc(9) types.  Exposed to
  325  * !_KERNEL so that monitoring tools can look up the zones with
  326  * libmemstat(3).
  327  */
  328 #define MBUF_MEM_NAME           "mbuf"
  329 #define MBUF_CLUSTER_MEM_NAME   "mbuf_cluster"
  330 #define MBUF_PACKET_MEM_NAME    "mbuf_packet"
  331 #define MBUF_JUMBOP_MEM_NAME    "mbuf_jumbo_page"
  332 #define MBUF_JUMBO9_MEM_NAME    "mbuf_jumbo_9k"
  333 #define MBUF_JUMBO16_MEM_NAME   "mbuf_jumbo_16k"
  334 #define MBUF_TAG_MEM_NAME       "mbuf_tag"
  335 #define MBUF_EXTREFCNT_MEM_NAME "mbuf_ext_refcnt"
  336 
  337 #ifdef _KERNEL
  338 
  339 #ifdef WITNESS
  340 #define MBUF_CHECKSLEEP(how) do {                                       \
  341         if (how == M_WAITOK)                                            \
  342                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,         \
  343                     "Sleeping in \"%s\"", __func__);                    \
  344 } while (0)
  345 #else
  346 #define MBUF_CHECKSLEEP(how)
  347 #endif
  348 
  349 /*
  350  * Network buffer allocation API
  351  *
  352  * The rest of it is defined in kern/kern_mbuf.c
  353  */
  354 
  355 extern uma_zone_t       zone_mbuf;
  356 extern uma_zone_t       zone_clust;
  357 extern uma_zone_t       zone_pack;
  358 extern uma_zone_t       zone_jumbop;
  359 extern uma_zone_t       zone_jumbo9;
  360 extern uma_zone_t       zone_jumbo16;
  361 extern uma_zone_t       zone_ext_refcnt;
  362 
  363 static __inline struct mbuf     *m_getcl(int how, short type, int flags);
  364 static __inline struct mbuf     *m_get(int how, short type);
  365 static __inline struct mbuf     *m_gethdr(int how, short type);
  366 static __inline struct mbuf     *m_getjcl(int how, short type, int flags,
  367                                     int size);
  368 static __inline struct mbuf     *m_getclr(int how, short type); /* XXX */
  369 static __inline int              m_init(struct mbuf *m, uma_zone_t zone,
  370                                     int size, int how, short type, int flags);
  371 static __inline struct mbuf     *m_free(struct mbuf *m);
  372 static __inline void             m_clget(struct mbuf *m, int how);
  373 static __inline void            *m_cljget(struct mbuf *m, int how, int size);
  374 static __inline void             m_chtype(struct mbuf *m, short new_type);
  375 void                             mb_free_ext(struct mbuf *);
  376 static __inline struct mbuf     *m_last(struct mbuf *m);
  377 int                              m_pkthdr_init(struct mbuf *m, int how);
  378 
  379 static __inline int
  380 m_gettype(int size)
  381 {
  382         int type;
  383         
  384         switch (size) {
  385         case MSIZE:
  386                 type = EXT_MBUF;
  387                 break;
  388         case MCLBYTES:
  389                 type = EXT_CLUSTER;
  390                 break;
  391 #if MJUMPAGESIZE != MCLBYTES
  392         case MJUMPAGESIZE:
  393                 type = EXT_JUMBOP;
  394                 break;
  395 #endif
  396         case MJUM9BYTES:
  397                 type = EXT_JUMBO9;
  398                 break;
  399         case MJUM16BYTES:
  400                 type = EXT_JUMBO16;
  401                 break;
  402         default:
  403                 panic("%s: m_getjcl: invalid cluster size", __func__);
  404         }
  405 
  406         return (type);
  407 }
  408 
  409 static __inline uma_zone_t
  410 m_getzone(int size)
  411 {
  412         uma_zone_t zone;
  413         
  414         switch (size) {
  415         case MSIZE:
  416                 zone = zone_mbuf;
  417                 break;
  418         case MCLBYTES:
  419                 zone = zone_clust;
  420                 break;
  421 #if MJUMPAGESIZE != MCLBYTES
  422         case MJUMPAGESIZE:
  423                 zone = zone_jumbop;
  424                 break;
  425 #endif
  426         case MJUM9BYTES:
  427                 zone = zone_jumbo9;
  428                 break;
  429         case MJUM16BYTES:
  430                 zone = zone_jumbo16;
  431                 break;
  432         default:
  433                 panic("%s: m_getjcl: invalid cluster type", __func__);
  434         }
  435 
  436         return (zone);
  437 }
  438 
  439 /*
  440  * Initialize an mbuf with linear storage.
  441  *
  442  * Inline because the consumer text overhead will be roughly the same to
  443  * initialize or call a function with this many parameters and M_PKTHDR
  444  * should go away with constant propagation for !MGETHDR.
  445  */
  446 static __inline int
  447 m_init(struct mbuf *m, uma_zone_t zone, int size, int how, short type,
  448     int flags)
  449 {
  450         int error;
  451 
  452         m->m_next = NULL;
  453         m->m_nextpkt = NULL;
  454         m->m_data = m->m_dat;
  455         m->m_len = 0;
  456         m->m_flags = flags;
  457         m->m_type = type;
  458         if (flags & M_PKTHDR) {
  459                 if ((error = m_pkthdr_init(m, how)) != 0)
  460                         return (error);
  461         }
  462 
  463         return (0);
  464 }
  465 
  466 static __inline struct mbuf *
  467 m_get(int how, short type)
  468 {
  469         struct mb_args args;
  470 
  471         args.flags = 0;
  472         args.type = type;
  473         return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
  474 }
  475 
  476 /*
  477  * XXX This should be deprecated, very little use.
  478  */
  479 static __inline struct mbuf *
  480 m_getclr(int how, short type)
  481 {
  482         struct mbuf *m;
  483         struct mb_args args;
  484 
  485         args.flags = 0;
  486         args.type = type;
  487         m = uma_zalloc_arg(zone_mbuf, &args, how);
  488         if (m != NULL)
  489                 bzero(m->m_data, MLEN);
  490         return (m);
  491 }
  492 
  493 static __inline struct mbuf *
  494 m_gethdr(int how, short type)
  495 {
  496         struct mb_args args;
  497 
  498         args.flags = M_PKTHDR;
  499         args.type = type;
  500         return ((struct mbuf *)(uma_zalloc_arg(zone_mbuf, &args, how)));
  501 }
  502 
  503 static __inline struct mbuf *
  504 m_getcl(int how, short type, int flags)
  505 {
  506         struct mb_args args;
  507 
  508         args.flags = flags;
  509         args.type = type;
  510         return ((struct mbuf *)(uma_zalloc_arg(zone_pack, &args, how)));
  511 }
  512 
  513 /*
  514  * m_getjcl() returns an mbuf with a cluster of the specified size attached.
  515  * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
  516  *
  517  * XXX: This is rather large, should be real function maybe.
  518  */
  519 static __inline struct mbuf *
  520 m_getjcl(int how, short type, int flags, int size)
  521 {
  522         struct mb_args args;
  523         struct mbuf *m, *n;
  524         uma_zone_t zone;
  525 
  526         args.flags = flags;
  527         args.type = type;
  528 
  529         m = uma_zalloc_arg(zone_mbuf, &args, how);
  530         if (m == NULL)
  531                 return (NULL);
  532 
  533         zone = m_getzone(size);
  534         n = uma_zalloc_arg(zone, m, how);
  535         if (n == NULL) {
  536                 uma_zfree(zone_mbuf, m);
  537                 return (NULL);
  538         }
  539         return (m);
  540 }
  541 
  542 static __inline void
  543 m_free_fast(struct mbuf *m)
  544 {
  545 #ifdef INVARIANTS
  546         if (m->m_flags & M_PKTHDR)
  547                 KASSERT(SLIST_EMPTY(&m->m_pkthdr.tags), ("doing fast free of mbuf with tags"));
  548 #endif
  549         
  550         uma_zfree_arg(zone_mbuf, m, (void *)MB_NOTAGS);
  551 }
  552 
  553 static __inline struct mbuf *
  554 m_free(struct mbuf *m)
  555 {
  556         struct mbuf *n = m->m_next;
  557 
  558         if (m->m_flags & M_EXT)
  559                 mb_free_ext(m);
  560         else if ((m->m_flags & M_NOFREE) == 0)
  561                 uma_zfree(zone_mbuf, m);
  562         return (n);
  563 }
  564 
  565 static __inline void
  566 m_clget(struct mbuf *m, int how)
  567 {
  568 
  569         if (m->m_flags & M_EXT)
  570                 printf("%s: %p mbuf already has cluster\n", __func__, m);
  571         m->m_ext.ext_buf = (char *)NULL;
  572         uma_zalloc_arg(zone_clust, m, how);
  573         /*
  574          * On a cluster allocation failure, drain the packet zone and retry,
  575          * we might be able to loosen a few clusters up on the drain.
  576          */
  577         if ((how & M_NOWAIT) && (m->m_ext.ext_buf == NULL)) {
  578                 zone_drain(zone_pack);
  579                 uma_zalloc_arg(zone_clust, m, how);
  580         }
  581 }
  582 
  583 /*
  584  * m_cljget() is different from m_clget() as it can allocate clusters without
  585  * attaching them to an mbuf.  In that case the return value is the pointer
  586  * to the cluster of the requested size.  If an mbuf was specified, it gets
  587  * the cluster attached to it and the return value can be safely ignored.
  588  * For size it takes MCLBYTES, MJUMPAGESIZE, MJUM9BYTES, MJUM16BYTES.
  589  */
  590 static __inline void *
  591 m_cljget(struct mbuf *m, int how, int size)
  592 {
  593         uma_zone_t zone;
  594 
  595         if (m && m->m_flags & M_EXT)
  596                 printf("%s: %p mbuf already has cluster\n", __func__, m);
  597         if (m != NULL)
  598                 m->m_ext.ext_buf = NULL;
  599 
  600         zone = m_getzone(size);
  601         return (uma_zalloc_arg(zone, m, how));
  602 }
  603 
  604 static __inline void
  605 m_cljset(struct mbuf *m, void *cl, int type)
  606 {
  607         uma_zone_t zone;
  608         int size;
  609         
  610         switch (type) {
  611         case EXT_CLUSTER:
  612                 size = MCLBYTES;
  613                 zone = zone_clust;
  614                 break;
  615 #if MJUMPAGESIZE != MCLBYTES
  616         case EXT_JUMBOP:
  617                 size = MJUMPAGESIZE;
  618                 zone = zone_jumbop;
  619                 break;
  620 #endif
  621         case EXT_JUMBO9:
  622                 size = MJUM9BYTES;
  623                 zone = zone_jumbo9;
  624                 break;
  625         case EXT_JUMBO16:
  626                 size = MJUM16BYTES;
  627                 zone = zone_jumbo16;
  628                 break;
  629         default:
  630                 panic("unknown cluster type");
  631                 break;
  632         }
  633 
  634         m->m_data = m->m_ext.ext_buf = cl;
  635         m->m_ext.ext_free = m->m_ext.ext_arg1 = m->m_ext.ext_arg2 = NULL;
  636         m->m_ext.ext_size = size;
  637         m->m_ext.ext_type = type;
  638         m->m_ext.ref_cnt = uma_find_refcnt(zone, cl);
  639         m->m_flags |= M_EXT;
  640 
  641 }
  642 
  643 static __inline void
  644 m_chtype(struct mbuf *m, short new_type)
  645 {
  646 
  647         m->m_type = new_type;
  648 }
  649 
  650 static __inline struct mbuf *
  651 m_last(struct mbuf *m)
  652 {
  653 
  654         while (m->m_next)
  655                 m = m->m_next;
  656         return (m);
  657 }
  658 
  659 /*
  660  * mbuf, cluster, and external object allocation macros (for compatibility
  661  * purposes).
  662  */
  663 #define M_MOVE_PKTHDR(to, from) m_move_pkthdr((to), (from))
  664 #define MGET(m, how, type)      ((m) = m_get((how), (type)))
  665 #define MGETHDR(m, how, type)   ((m) = m_gethdr((how), (type)))
  666 #define MCLGET(m, how)          m_clget((m), (how))
  667 #define MEXTADD(m, buf, size, free, arg1, arg2, flags, type)            \
  668     m_extadd((m), (caddr_t)(buf), (size), (free),(arg1),(arg2),(flags), (type))
  669 #define m_getm(m, len, how, type)                                       \
  670     m_getm2((m), (len), (how), (type), M_PKTHDR)
  671 
  672 /*
  673  * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
  674  * be both the local data payload, or an external buffer area, depending on
  675  * whether M_EXT is set).
  676  */
  677 #define M_WRITABLE(m)   (!((m)->m_flags & M_RDONLY) &&                  \
  678                          (!(((m)->m_flags & M_EXT)) ||                  \
  679                          (*((m)->m_ext.ref_cnt) == 1)) )                \
  680 
  681 /* Check if the supplied mbuf has a packet header, or else panic. */
  682 #define M_ASSERTPKTHDR(m)                                               \
  683         KASSERT((m) != NULL && (m)->m_flags & M_PKTHDR,                 \
  684             ("%s: no mbuf packet header!", __func__))
  685 
  686 /*
  687  * Ensure that the supplied mbuf is a valid, non-free mbuf.
  688  *
  689  * XXX: Broken at the moment.  Need some UMA magic to make it work again.
  690  */
  691 #define M_ASSERTVALID(m)                                                \
  692         KASSERT((((struct mbuf *)m)->m_flags & 0) == 0,                 \
  693             ("%s: attempted use of a free mbuf!", __func__))
  694 
  695 /*
  696  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place an
  697  * object of the specified size at the end of the mbuf, longword aligned.
  698  */
  699 #define M_ALIGN(m, len) do {                                            \
  700         KASSERT(!((m)->m_flags & (M_PKTHDR|M_EXT)),                     \
  701                 ("%s: M_ALIGN not normal mbuf", __func__));             \
  702         KASSERT((m)->m_data == (m)->m_dat,                              \
  703                 ("%s: M_ALIGN not a virgin mbuf", __func__));           \
  704         (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1);            \
  705 } while (0)
  706 
  707 /*
  708  * As above, for mbufs allocated with m_gethdr/MGETHDR or initialized by
  709  * M_DUP/MOVE_PKTHDR.
  710  */
  711 #define MH_ALIGN(m, len) do {                                           \
  712         KASSERT((m)->m_flags & M_PKTHDR && !((m)->m_flags & M_EXT),     \
  713                 ("%s: MH_ALIGN not PKTHDR mbuf", __func__));            \
  714         KASSERT((m)->m_data == (m)->m_pktdat,                           \
  715                 ("%s: MH_ALIGN not a virgin mbuf", __func__));          \
  716         (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1);           \
  717 } while (0)
  718 
  719 /*
  720  * Compute the amount of space available before the current start of data in
  721  * an mbuf.
  722  *
  723  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  724  * of checking writability of the mbuf data area rests solely with the caller.
  725  */
  726 #define M_LEADINGSPACE(m)                                               \
  727         ((m)->m_flags & M_EXT ?                                         \
  728             (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0):     \
  729             (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat :     \
  730             (m)->m_data - (m)->m_dat)
  731 
  732 /*
  733  * Compute the amount of space available after the end of data in an mbuf.
  734  *
  735  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  736  * of checking writability of the mbuf data area rests solely with the caller.
  737  */
  738 #define M_TRAILINGSPACE(m)                                              \
  739         ((m)->m_flags & M_EXT ?                                         \
  740             (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size   \
  741                 - ((m)->m_data + (m)->m_len) : 0) :                     \
  742             &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
  743 
  744 /*
  745  * Arrange to prepend space of size plen to mbuf m.  If a new mbuf must be
  746  * allocated, how specifies whether to wait.  If the allocation fails, the
  747  * original mbuf chain is freed and m is set to NULL.
  748  */
  749 #define M_PREPEND(m, plen, how) do {                                    \
  750         struct mbuf **_mmp = &(m);                                      \
  751         struct mbuf *_mm = *_mmp;                                       \
  752         int _mplen = (plen);                                            \
  753         int __mhow = (how);                                             \
  754                                                                         \
  755         MBUF_CHECKSLEEP(how);                                           \
  756         if (M_LEADINGSPACE(_mm) >= _mplen) {                            \
  757                 _mm->m_data -= _mplen;                                  \
  758                 _mm->m_len += _mplen;                                   \
  759         } else                                                          \
  760                 _mm = m_prepend(_mm, _mplen, __mhow);                   \
  761         if (_mm != NULL && _mm->m_flags & M_PKTHDR)                     \
  762                 _mm->m_pkthdr.len += _mplen;                            \
  763         *_mmp = _mm;                                                    \
  764 } while (0)
  765 
  766 /*
  767  * Change mbuf to new type.  This is a relatively expensive operation and
  768  * should be avoided.
  769  */
  770 #define MCHTYPE(m, t)   m_chtype((m), (t))
  771 
  772 /* Length to m_copy to copy all. */
  773 #define M_COPYALL       1000000000
  774 
  775 /* Compatibility with 4.3. */
  776 #define m_copy(m, o, l) m_copym((m), (o), (l), M_DONTWAIT)
  777 
  778 extern int              max_datalen;    /* MHLEN - max_hdr */
  779 extern int              max_hdr;        /* Largest link + protocol header */
  780 extern int              max_linkhdr;    /* Largest link-level header */
  781 extern int              max_protohdr;   /* Largest protocol header */
  782 extern struct mbstat    mbstat;         /* General mbuf stats/infos */
  783 extern int              nmbclusters;    /* Maximum number of clusters */
  784 
  785 struct uio;
  786 
  787 void             m_adj(struct mbuf *, int);
  788 void             m_align(struct mbuf *, int);
  789 int              m_apply(struct mbuf *, int, int,
  790                     int (*)(void *, void *, u_int), void *);
  791 int              m_append(struct mbuf *, int, c_caddr_t);
  792 void             m_cat(struct mbuf *, struct mbuf *);
  793 void             m_extadd(struct mbuf *, caddr_t, u_int,
  794                     void (*)(void *, void *), void *, void *, int, int);
  795 struct mbuf     *m_collapse(struct mbuf *, int, int);
  796 void             m_copyback(struct mbuf *, int, int, c_caddr_t);
  797 void             m_copydata(const struct mbuf *, int, int, caddr_t);
  798 struct mbuf     *m_copym(struct mbuf *, int, int, int);
  799 struct mbuf     *m_copymdata(struct mbuf *, struct mbuf *,
  800                     int, int, int, int);
  801 struct mbuf     *m_copypacket(struct mbuf *, int);
  802 void             m_copy_pkthdr(struct mbuf *, struct mbuf *);
  803 struct mbuf     *m_copyup(struct mbuf *n, int len, int dstoff);
  804 struct mbuf     *m_defrag(struct mbuf *, int);
  805 void             m_demote(struct mbuf *, int);
  806 struct mbuf     *m_devget(char *, int, int, struct ifnet *,
  807                     void (*)(char *, caddr_t, u_int));
  808 struct mbuf     *m_dup(struct mbuf *, int);
  809 int              m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
  810 u_int            m_fixhdr(struct mbuf *);
  811 struct mbuf     *m_fragment(struct mbuf *, int, int);
  812 void             m_freem(struct mbuf *);
  813 struct mbuf     *m_getm2(struct mbuf *, int, int, short, int);
  814 struct mbuf     *m_getptr(struct mbuf *, int, int *);
  815 u_int            m_length(struct mbuf *, struct mbuf **);
  816 int              m_mbuftouio(struct uio *, struct mbuf *, int);
  817 void             m_move_pkthdr(struct mbuf *, struct mbuf *);
  818 struct mbuf     *m_prepend(struct mbuf *, int, int);
  819 void             m_print(const struct mbuf *, int);
  820 struct mbuf     *m_pulldown(struct mbuf *, int, int, int *);
  821 struct mbuf     *m_pullup(struct mbuf *, int);
  822 int             m_sanity(struct mbuf *, int);
  823 struct mbuf     *m_split(struct mbuf *, int, int);
  824 struct mbuf     *m_uiotombuf(struct uio *, int, int, int, int);
  825 struct mbuf     *m_unshare(struct mbuf *, int how);
  826 
  827 /*-
  828  * Network packets may have annotations attached by affixing a list of
  829  * "packet tags" to the pkthdr structure.  Packet tags are dynamically
  830  * allocated semi-opaque data structures that have a fixed header
  831  * (struct m_tag) that specifies the size of the memory block and a
  832  * <cookie,type> pair that identifies it.  The cookie is a 32-bit unique
  833  * unsigned value used to identify a module or ABI.  By convention this value
  834  * is chosen as the date+time that the module is created, expressed as the
  835  * number of seconds since the epoch (e.g., using date -u +'%s').  The type
  836  * value is an ABI/module-specific value that identifies a particular
  837  * annotation and is private to the module.  For compatibility with systems
  838  * like OpenBSD that define packet tags w/o an ABI/module cookie, the value
  839  * PACKET_ABI_COMPAT is used to implement m_tag_get and m_tag_find
  840  * compatibility shim functions and several tag types are defined below.
  841  * Users that do not require compatibility should use a private cookie value
  842  * so that packet tag-related definitions can be maintained privately.
  843  *
  844  * Note that the packet tag returned by m_tag_alloc has the default memory
  845  * alignment implemented by malloc.  To reference private data one can use a
  846  * construct like:
  847  *
  848  *      struct m_tag *mtag = m_tag_alloc(...);
  849  *      struct foo *p = (struct foo *)(mtag+1);
  850  *
  851  * if the alignment of struct m_tag is sufficient for referencing members of
  852  * struct foo.  Otherwise it is necessary to embed struct m_tag within the
  853  * private data structure to insure proper alignment; e.g.,
  854  *
  855  *      struct foo {
  856  *              struct m_tag    tag;
  857  *              ...
  858  *      };
  859  *      struct foo *p = (struct foo *) m_tag_alloc(...);
  860  *      struct m_tag *mtag = &p->tag;
  861  */
  862 
  863 /*
  864  * Persistent tags stay with an mbuf until the mbuf is reclaimed.  Otherwise
  865  * tags are expected to ``vanish'' when they pass through a network
  866  * interface.  For most interfaces this happens normally as the tags are
  867  * reclaimed when the mbuf is free'd.  However in some special cases
  868  * reclaiming must be done manually.  An example is packets that pass through
  869  * the loopback interface.  Also, one must be careful to do this when
  870  * ``turning around'' packets (e.g., icmp_reflect).
  871  *
  872  * To mark a tag persistent bit-or this flag in when defining the tag id.
  873  * The tag will then be treated as described above.
  874  */
  875 #define MTAG_PERSISTENT                         0x800
  876 
  877 #define PACKET_TAG_NONE                         0  /* Nadda */
  878 
  879 /* Packet tags for use with PACKET_ABI_COMPAT. */
  880 #define PACKET_TAG_IPSEC_IN_DONE                1  /* IPsec applied, in */
  881 #define PACKET_TAG_IPSEC_OUT_DONE               2  /* IPsec applied, out */
  882 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE         3  /* NIC IPsec crypto done */
  883 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED      4  /* NIC IPsec crypto req'ed */
  884 #define PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO     5  /* NIC notifies IPsec */
  885 #define PACKET_TAG_IPSEC_PENDING_TDB            6  /* Reminder to do IPsec */
  886 #define PACKET_TAG_BRIDGE                       7  /* Bridge processing done */
  887 #define PACKET_TAG_GIF                          8  /* GIF processing done */
  888 #define PACKET_TAG_GRE                          9  /* GRE processing done */
  889 #define PACKET_TAG_IN_PACKET_CHECKSUM           10 /* NIC checksumming done */
  890 #define PACKET_TAG_ENCAP                        11 /* Encap.  processing */
  891 #define PACKET_TAG_IPSEC_SOCKET                 12 /* IPSEC socket ref */
  892 #define PACKET_TAG_IPSEC_HISTORY                13 /* IPSEC history */
  893 #define PACKET_TAG_IPV6_INPUT                   14 /* IPV6 input processing */
  894 #define PACKET_TAG_DUMMYNET                     15 /* dummynet info */
  895 #define PACKET_TAG_DIVERT                       17 /* divert info */
  896 #define PACKET_TAG_IPFORWARD                    18 /* ipforward info */
  897 #define PACKET_TAG_MACLABEL     (19 | MTAG_PERSISTENT) /* MAC label */
  898 #define PACKET_TAG_PF                           21 /* PF + ALTQ information */
  899 #define PACKET_TAG_RTSOCKFAM                    25 /* rtsock sa family */
  900 #define PACKET_TAG_IPOPTIONS                    27 /* Saved IP options */
  901 #define PACKET_TAG_CARP                         28 /* CARP info */
  902 #define PACKET_TAG_IPSEC_NAT_T_PORTS            29 /* two uint16_t */
  903 
  904 /* Specific cookies and tags. */
  905 
  906 /* Packet tag routines. */
  907 struct m_tag    *m_tag_alloc(u_int32_t, int, int, int);
  908 void             m_tag_delete(struct mbuf *, struct m_tag *);
  909 void             m_tag_delete_chain(struct mbuf *, struct m_tag *);
  910 void             m_tag_free_default(struct m_tag *);
  911 struct m_tag    *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
  912 struct m_tag    *m_tag_copy(struct m_tag *, int);
  913 int              m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
  914 void             m_tag_delete_nonpersistent(struct mbuf *);
  915 
  916 /*
  917  * Initialize the list of tags associated with an mbuf.
  918  */
  919 static __inline void
  920 m_tag_init(struct mbuf *m)
  921 {
  922 
  923         SLIST_INIT(&m->m_pkthdr.tags);
  924 }
  925 
  926 /*
  927  * Set up the contents of a tag.  Note that this does not fill in the free
  928  * method; the caller is expected to do that.
  929  *
  930  * XXX probably should be called m_tag_init, but that was already taken.
  931  */
  932 static __inline void
  933 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
  934 {
  935 
  936         t->m_tag_id = type;
  937         t->m_tag_len = len;
  938         t->m_tag_cookie = cookie;
  939 }
  940 
  941 /*
  942  * Reclaim resources associated with a tag.
  943  */
  944 static __inline void
  945 m_tag_free(struct m_tag *t)
  946 {
  947 
  948         (*t->m_tag_free)(t);
  949 }
  950 
  951 /*
  952  * Return the first tag associated with an mbuf.
  953  */
  954 static __inline struct m_tag *
  955 m_tag_first(struct mbuf *m)
  956 {
  957 
  958         return (SLIST_FIRST(&m->m_pkthdr.tags));
  959 }
  960 
  961 /*
  962  * Return the next tag in the list of tags associated with an mbuf.
  963  */
  964 static __inline struct m_tag *
  965 m_tag_next(struct mbuf *m, struct m_tag *t)
  966 {
  967 
  968         return (SLIST_NEXT(t, m_tag_link));
  969 }
  970 
  971 /*
  972  * Prepend a tag to the list of tags associated with an mbuf.
  973  */
  974 static __inline void
  975 m_tag_prepend(struct mbuf *m, struct m_tag *t)
  976 {
  977 
  978         SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
  979 }
  980 
  981 /*
  982  * Unlink a tag from the list of tags associated with an mbuf.
  983  */
  984 static __inline void
  985 m_tag_unlink(struct mbuf *m, struct m_tag *t)
  986 {
  987 
  988         SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
  989 }
  990 
  991 /* These are for OpenBSD compatibility. */
  992 #define MTAG_ABI_COMPAT         0               /* compatibility ABI */
  993 
  994 static __inline struct m_tag *
  995 m_tag_get(int type, int length, int wait)
  996 {
  997         return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
  998 }
  999 
 1000 static __inline struct m_tag *
 1001 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
 1002 {
 1003         return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL :
 1004             m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
 1005 }
 1006 
 1007 /* XXX temporary FIB methods probably eventually use tags.*/
 1008 #define M_FIBSHIFT    28
 1009 #define M_FIBMASK       0x0F
 1010 
 1011 /* get the fib from an mbuf and if it is not set, return the default */
 1012 #define M_GETFIB(_m) \
 1013     ((((_m)->m_flags & M_FIB) >> M_FIBSHIFT) & M_FIBMASK)
 1014 
 1015 #define M_SETFIB(_m, _fib) do {                                         \
 1016         _m->m_flags &= ~M_FIB;                                          \
 1017         _m->m_flags |= (((_fib) << M_FIBSHIFT) & M_FIB);  \
 1018 } while (0) 
 1019 
 1020 #endif /* _KERNEL */
 1021 
 1022 #ifdef MBUF_PROFILING
 1023  void m_profile(struct mbuf *m);
 1024  #define M_PROFILE(m) m_profile(m)
 1025 #else
 1026  #define M_PROFILE(m)
 1027 #endif
 1028 
 1029 
 1030 #endif /* !_SYS_MBUF_H_ */

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