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) 2004 The DragonFly Project.  All rights reserved.
    3  *
    4  * Copyright (c) 1982, 1986, 1988, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 3. All advertising materials mentioning features or use of this software
   16  *    must display the following acknowledgement:
   17  *      This product includes software developed by the University of
   18  *      California, Berkeley and its contributors.
   19  * 4. Neither the name of the University nor the names of its contributors
   20  *    may be used to endorse or promote products derived from this software
   21  *    without specific prior written permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  *
   35  *      @(#)mbuf.h      8.5 (Berkeley) 2/19/95
   36  * $FreeBSD: src/sys/sys/mbuf.h,v 1.44.2.17 2003/04/15 06:15:02 silby Exp $
   37  * $DragonFly: src/sys/sys/mbuf.h,v 1.54 2008/10/19 08:39:55 sephe Exp $
   38  */
   39 
   40 #ifndef _SYS_MBUF_H_
   41 #define _SYS_MBUF_H_
   42 
   43 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
   44 
   45 #ifndef _SYS_TYPES_H_
   46 #include <sys/types.h>
   47 #endif
   48 #ifndef _SYS_PARAM_H_
   49 #include <sys/param.h>
   50 #endif
   51 #ifndef _SYS_QUEUE_H_
   52 #include <sys/queue.h>
   53 #endif
   54 #ifndef _NET_NETISR_H_
   55 #include <net/netisr.h>
   56 #endif
   57 #ifndef _NET_ETHERNET_H_
   58 #include <net/ethernet.h>
   59 #endif
   60 
   61 /*
   62  * Mbufs are of a single size, MSIZE (machine/param.h), which
   63  * includes overhead.  An mbuf may add a single "mbuf cluster" of size
   64  * MCLBYTES (also in machine/param.h), which has no additional overhead
   65  * and is used instead of the internal data area; this is done when
   66  * at least MINCLSIZE of data must be stored.
   67  */
   68 #define MLEN            (MSIZE - sizeof(struct m_hdr))  /* normal data len */
   69 #define MHLEN           (MLEN - sizeof(struct pkthdr))  /* data len w/pkthdr */
   70 #define MINCLSIZE       (MHLEN + 1)     /* smallest amount to put in cluster */
   71 #define M_MAXCOMPRESS   (MHLEN / 2)     /* max amount to copy for compression */
   72 
   73 /*
   74  * Macros for type conversion:
   75  * mtod(m, t)           -- Convert mbuf pointer to data pointer of correct type.
   76  * mtodoff(m, t, off)   -- Convert mbuf pointer at the specified offset to data
   77  *                         pointer of correct type.
   78  */
   79 #define mtod(m, t)              ((t)((m)->m_data))
   80 #define mtodoff(m, t, off)      ((t)((m)->m_data + (off)))
   81 
   82 /*
   83  * Header present at the beginning of every mbuf.
   84  */
   85 struct m_hdr {
   86         struct  mbuf *mh_next;          /* next buffer in chain */
   87         struct  mbuf *mh_nextpkt;       /* next chain in queue/record */
   88         caddr_t mh_data;                /* location of data */
   89         int     mh_len;                 /* amount of data in this mbuf */
   90         int     mh_flags;               /* flags; see below */
   91         short   mh_type;                /* type of data in this mbuf */
   92         short   mh_pad;                 /* padding */
   93         /* XXX implicit 4 bytes padding on x86_64 */
   94 #ifdef MBUF_DEBUG
   95         const char *mh_lastfunc;
   96 #endif
   97         union {
   98                 struct netmsg_packet mhm_pkt;   /* hardware->proto stack msg */
   99                 struct netmsg_pru_send mhm_snd; /* usrspace->proto stack msg */
  100                 struct netmsg_inarp mhm_arp;    /* proto stack<->route msg */
  101         } mh_msgu;
  102 };
  103 #define mh_netmsg       mh_msgu.mhm_pkt
  104 #define mh_sndmsg       mh_msgu.mhm_snd
  105 #define mh_arpmsg       mh_msgu.mhm_arp
  106 
  107 /* pf stuff */
  108 struct pkthdr_pf {
  109         void            *hdr;           /* saved hdr pos in mbuf, for ECN */
  110         void            *statekey;      /* pf stackside statekey */
  111         u_int           rtableid;       /* alternate routing table id */
  112         uint32_t        qid;            /* queue id */
  113         uint16_t        tag;            /* tag id */
  114         uint8_t         flags;
  115         uint8_t         routed;
  116         uint32_t        state_hash;     /* identifies 'connections' */
  117         uint8_t         ecn_af;         /* for altq_red */
  118         uint8_t         unused01;
  119         uint8_t         unused02;
  120         uint8_t         unused03;
  121         /* XXX implicit 4 bytes padding on x86_64 */
  122 };
  123 
  124 /* pkthdr_pf.flags */
  125 #define PF_TAG_GENERATED                0x01
  126 #define PF_TAG_FRAGCACHE                0x02
  127 #define PF_TAG_TRANSLATE_LOCALHOST      0x04
  128 #define PF_TAG_DIVERTED                 0x08
  129 #define PF_TAG_DIVERTED_PACKET          0x10
  130 #define PF_TAG_REROUTE                  0x20
  131 
  132 /*
  133  * Packet tag structure (see below for details).
  134  */
  135 struct m_tag {
  136         SLIST_ENTRY(m_tag)      m_tag_link;     /* List of packet tags */
  137         uint16_t                m_tag_id;       /* Tag ID */
  138         uint16_t                m_tag_len;      /* Length of data */
  139         uint32_t                m_tag_cookie;   /* ABI/Module ID */
  140 };
  141 
  142 SLIST_HEAD(packet_tags, m_tag);
  143 
  144 /*
  145  * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
  146  *
  147  * Be careful: The fields have been carefully ordered to avoid hidden padding.
  148  *             Keep this in mind, when adding or removing fields!
  149  */
  150 struct pkthdr {
  151         struct  ifnet *rcvif;           /* rcv interface */
  152         struct packet_tags tags;        /* list of packet tags */
  153 
  154         /* variables for ip and tcp reassembly */
  155         void    *header;                /* pointer to packet header */
  156         int     len;                    /* total packet length */
  157 
  158         /* variables for hardware checksum */
  159         int     csum_flags;             /* flags regarding checksum */
  160         int     csum_data;              /* data field used by csum routines */
  161         uint16_t csum_iphlen;           /* IP header length */
  162                                         /* valid if CSUM IP|UDP|TCP|TSO */
  163         uint8_t csum_thlen;             /* TCP/UDP header length */
  164                                         /* valid if CSUM UDP|TCP|TSO */
  165         uint8_t csum_lhlen;             /* link header length */
  166 
  167         uint16_t tso_segsz;             /* TSO segment size */
  168         uint16_t ether_vlantag;         /* ethernet 802.1p+q vlan tag */
  169 
  170         uint16_t hash;                  /* packet hash */
  171         uint16_t unused1;               /* reserved for route table id */
  172         uint32_t unused2;               /* reserved for codel timestamp */
  173 
  174         uint16_t wlan_seqno;            /* IEEE 802.11 seq no. */
  175         /*
  176          * Valid if BRIDGE_MBUF_TAGGED is set in fw_flags, records
  177          * the original ether source address (if compatible).
  178          */
  179         uint8_t ether_br_shost[ETHER_ADDR_LEN];
  180 
  181         /* firewall flags */
  182         uint32_t fw_flags;              /* flags for FW */
  183 
  184         /* variables for PF processing */
  185         struct pkthdr_pf pf;            /* structure for PF */
  186 };
  187 
  188 /*
  189  * Description of external storage mapped into mbuf; valid only if M_EXT is set.
  190  */
  191 struct m_ext {
  192         caddr_t ext_buf;                /* start of buffer */
  193         void    (*ext_free)(void *);
  194         u_int   ext_size;               /* size of buffer, for ext_free */
  195         void    (*ext_ref)(void *);
  196         void    *ext_arg;
  197 };
  198 
  199 /*
  200  * The core of the mbuf object along with some shortcut defines for
  201  * practical purposes.
  202  */
  203 struct mbuf {
  204         struct  m_hdr m_hdr;
  205         union {
  206                 struct {
  207                         struct  pkthdr MH_pkthdr;       /* M_PKTHDR set */
  208                         union {
  209                                 struct  m_ext MH_ext;   /* M_EXT set */
  210                                 char    MH_databuf[MHLEN];
  211                         } MH_dat;
  212                 } MH;
  213                 char    M_databuf[MLEN];                /* !M_PKTHDR, !M_EXT */
  214         } M_dat;
  215 };
  216 #define m_next          m_hdr.mh_next
  217 #define m_len           m_hdr.mh_len
  218 #define m_data          m_hdr.mh_data
  219 #define m_type          m_hdr.mh_type
  220 #define m_flags         m_hdr.mh_flags
  221 #define m_nextpkt       m_hdr.mh_nextpkt
  222 #define m_pkthdr        M_dat.MH.MH_pkthdr
  223 #define m_ext           M_dat.MH.MH_dat.MH_ext
  224 #define m_pktdat        M_dat.MH.MH_dat.MH_databuf
  225 #define m_dat           M_dat.M_databuf
  226 
  227 /*
  228  * Code that uses m_act should be converted to use m_nextpkt
  229  * instead; m_act is historical and deprecated.
  230  */
  231 #define m_act           m_nextpkt
  232 
  233 /*
  234  * mbuf flags.
  235  */
  236 #define M_EXT           0x0001  /* has associated external storage */
  237 #define M_PKTHDR        0x0002  /* start of record */
  238 #define M_EOR           0x0004  /* end of record */
  239 #define M_PROTO1        0x0008  /* protocol-specific */
  240 #define M_PROTO2        0x0010  /* protocol-specific */
  241 #define M_PROTO3        0x0020  /* protocol-specific */
  242 #define M_PROTO4        0x0040  /* protocol-specific */
  243 #define M_PROTO5        0x0080  /* protocol-specific */
  244 
  245 /*
  246  * mbuf pkthdr flags (also stored in m_flags).
  247  */
  248 #define M_BCAST         0x0100  /* send/received as link-level broadcast */
  249 #define M_MCAST         0x0200  /* send/received as link-level multicast */
  250 #define M_FRAG          0x0400  /* packet is a fragment of a larger packet */
  251 #define M_FIRSTFRAG     0x0800  /* packet is first fragment */
  252 #define M_LASTFRAG      0x1000  /* packet is last fragment */
  253 #define M_CLCACHE       0x2000  /* mbuf allocated from the cluster cache */
  254 #define M_EXT_CLUSTER   0x4000  /* standard cluster else special */
  255 #define M_PHCACHE       0x8000  /* mbuf allocated from the pkt header cache */
  256 #define M_NOTIFICATION  0x10000 /* notification event */
  257 #define M_VLANTAG       0x20000 /* ether_vlantag is valid */
  258 #define M_MPLSLABELED   0x40000 /* packet is mpls labeled */
  259 #define M_LENCHECKED    0x80000 /* packet proto lengths are checked */
  260 #define M_HASH          0x100000/* hash field in pkthdr is valid */
  261 #define M_PROTO6        0x200000/* protocol-specific */
  262 #define M_PROTO7        0x400000/* protocol-specific */
  263 #define M_PROTO8        0x800000/* protocol-specific */
  264 #define M_CKHASH        0x1000000/* hash needs software verification */
  265 #define M_PRIO          0x2000000/* high priority mbuf */
  266 
  267 /*
  268  * Flags copied when copying m_pkthdr.
  269  */
  270 #define M_COPYFLAGS     (M_PKTHDR|M_EOR|M_PROTO1|M_PROTO2|M_PROTO3 | \
  271                          M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8 | \
  272                          M_BCAST|M_MCAST|M_FRAG|M_FIRSTFRAG|M_LASTFRAG | \
  273                          M_VLANTAG|M_MPLSLABELED | \
  274                          M_LENCHECKED|M_HASH|M_CKHASH|M_PRIO)
  275 
  276 /*
  277  * Flags indicating hw checksum support and sw checksum requirements.
  278  */
  279 #define CSUM_IP                 0x0001          /* will csum IP */
  280 #define CSUM_TCP                0x0002          /* will csum TCP */
  281 #define CSUM_UDP                0x0004          /* will csum UDP */
  282 #define CSUM_IP_FRAGS           0x0008          /* will csum IP fragments */
  283 #define CSUM_FRAGMENT           0x0010          /* will do IP fragmentation */
  284 
  285 #define CSUM_IP_CHECKED         0x0100          /* did csum IP */
  286 #define CSUM_IP_VALID           0x0200          /*   ... the csum is valid */
  287 #define CSUM_DATA_VALID         0x0400          /* csum_data field is valid */
  288 #define CSUM_PSEUDO_HDR         0x0800          /* csum_data has pseudo hdr */
  289 #define CSUM_FRAG_NOT_CHECKED   0x1000          /* did _not_ csum fragment
  290                                                  * NB: This flag is only used
  291                                                  * by IP defragmenter.
  292                                                  */
  293 #define CSUM_TSO                0x2000          /* will do TCP segmentation */
  294 
  295 #define CSUM_DELAY_DATA         (CSUM_TCP | CSUM_UDP)
  296 #define CSUM_DELAY_IP           (CSUM_IP)       /* XXX add ipv6 here too? */
  297 
  298 /*
  299  * Flags indicating PF processing status
  300  */
  301 #define FW_MBUF_GENERATED       0x00000001
  302 #define PF_MBUF_STRUCTURE       0x00000002      /* m_pkthdr.pf valid */
  303 #define PF_MBUF_ROUTED          0x00000004      /* pf_routed field is valid */
  304 #define PF_MBUF_TAGGED          0x00000008
  305 #define XX_MBUF_UNUSED10        0x00000010
  306 #define XX_MBUF_UNUSED20        0x00000020
  307 #define IPFORWARD_MBUF_TAGGED   0x00000040
  308 #define DUMMYNET_MBUF_TAGGED    0x00000080
  309 #define BRIDGE_MBUF_TAGGED      0x00000100
  310 #define FW_MBUF_REDISPATCH      0x00000200
  311 #define IPFW_MBUF_GENERATED     FW_MBUF_GENERATED
  312 /*
  313  * mbuf types.
  314  */
  315 #define MT_FREE         0       /* should be on free list */
  316 #define MT_DATA         1       /* dynamic (data) allocation */
  317 #define MT_HEADER       2       /* packet header */
  318 #define MT_SONAME       3       /* socket name */
  319 /* 4 was MT_TAG */
  320 #define MT_CONTROL      5       /* extra-data protocol message */
  321 #define MT_OOBDATA      6       /* expedited data  */
  322 #define MT_NTYPES       7       /* number of mbuf types for mbtypes[] */
  323 
  324 /*
  325  * General mbuf allocator statistics structure.
  326  *
  327  * NOTE: Make sure this struct's size is multiple cache line size.
  328  */
  329 struct mbstat {
  330         u_long  m_mbufs;        /* mbufs obtained from page pool */
  331         u_long  m_clusters;     /* clusters obtained from page pool */
  332         u_long  m_jclusters;    /* jclusters obtained from page pool */
  333         u_long  m_clfree;       /* free clusters */
  334         u_long  m_drops;        /* times failed to find space */
  335         u_long  m_wait;         /* times waited for space */
  336         u_long  m_drain;        /* times drained protocols for space */
  337         u_long  m_mcfail;       /* times m_copym failed */
  338         u_long  m_mpfail;       /* times m_pullup failed */
  339         u_long  m_msize;        /* length of an mbuf */
  340         u_long  m_mclbytes;     /* length of an mbuf cluster */
  341         u_long  m_mjumpagesize; /* length of a jumbo mbuf cluster */
  342         u_long  m_minclsize;    /* min length of data to allocate a cluster */
  343         u_long  m_mlen;         /* length of data in an mbuf */
  344         u_long  m_mhlen;        /* length of data in a header mbuf */
  345         u_long  m_pad;          /* pad to cache line size (64B) */
  346 };
  347 
  348 /*
  349  * Flags specifying how an allocation should be made.
  350  */
  351 
  352 #define MB_DONTWAIT     0x4
  353 #define MB_TRYWAIT      0x8
  354 #define MB_WAIT         MB_TRYWAIT
  355 
  356 /*
  357  * Mbuf to Malloc Flag Conversion.
  358  */
  359 #define MBTOM(how)      ((how) & MB_TRYWAIT ? M_WAITOK : M_NOWAIT)
  360 
  361 /*
  362  * These are identifying numbers passed to the m_mballoc_wait function,
  363  * allowing us to determine whether the call came from an MGETHDR or
  364  * an MGET.
  365  */
  366 #define MGETHDR_C      1
  367 #define MGET_C         2
  368 
  369 /*
  370  * mbuf allocation/deallocation macros (YYY deprecated, too big):
  371  *
  372  *      MGET(struct mbuf *m, int how, int type)
  373  * allocates an mbuf and initializes it to contain internal data.
  374  *
  375  *      MGETHDR(struct mbuf *m, int how, int type)
  376  * allocates an mbuf and initializes it to contain a packet header
  377  * and internal data.
  378  */
  379 #define MGET(m, how, type) do {                                         \
  380         (m) = m_get((how), (type));                                     \
  381 } while (0)
  382 
  383 #define MGETHDR(m, how, type) do {                                      \
  384         (m) = m_gethdr((how), (type));                                  \
  385 } while (0)
  386 
  387 /*
  388  * MCLGET adds such clusters to a normal mbuf.  The flag M_EXT is set upon
  389  * success.
  390  * Deprecated.  Use m_getcl() or m_getl() instead.
  391  */
  392 #define MCLGET(m, how) do {                                             \
  393         m_mclget((m), (how));                                           \
  394 } while (0)
  395 
  396 /*
  397  * NB: M_COPY_PKTHDR is deprecated; use either M_MOVE_PKTHDR
  398  *     or m_dup_pkthdr.
  399  */
  400 /*
  401  * Move mbuf pkthdr from "from" to "to".
  402  * from should have M_PKTHDR set, and to must be empty.
  403  * from no longer has a pkthdr after this operation.
  404  */
  405 #define M_MOVE_PKTHDR(_to, _from)       m_move_pkthdr((_to), (_from))
  406 
  407 /*
  408  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
  409  * an object of the specified size at the end of the mbuf, longword aligned.
  410  */
  411 #define M_ALIGN(m, len) do {                                            \
  412         (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1);            \
  413 } while (0)
  414 
  415 /*
  416  * As above, for mbufs allocated with m_gethdr/MGETHDR
  417  * or initialized by M_COPY_PKTHDR.
  418  */
  419 #define MH_ALIGN(m, len) do {                                           \
  420         (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1);           \
  421 } while (0)
  422 
  423 /*
  424  * Check if we can write to an mbuf.
  425  */
  426 #define M_EXT_WRITABLE(m)       (m_sharecount(m) == 1)
  427 #define M_WRITABLE(m)           (!((m)->m_flags & M_EXT) || M_EXT_WRITABLE(m))
  428 
  429 /*
  430  * Check if the supplied mbuf has a packet header, or else panic.
  431  */
  432 #define M_ASSERTPKTHDR(m)                                               \
  433         KASSERT(m != NULL && m->m_flags & M_PKTHDR,                     \
  434                 ("%s: invalid mbuf or no mbuf packet header!", __func__))
  435 
  436 /*
  437  * Compute the amount of space available before the current start of data.
  438  * The M_EXT_WRITABLE() is a temporary, conservative safety measure: the burden
  439  * of checking writability of the mbuf data area rests solely with the caller.
  440  */
  441 #define M_LEADINGSPACE(m)                                               \
  442         ((m)->m_flags & M_EXT ?                                         \
  443             (M_EXT_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \
  444             (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat :     \
  445             (m)->m_data - (m)->m_dat)
  446 
  447 /*
  448  * Compute the amount of space available after the end of data in an mbuf.
  449  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  450  * of checking writability of the mbuf data area rests solely with the caller.
  451  */
  452 #define M_TRAILINGSPACE(m)                                              \
  453         ((m)->m_flags & M_EXT ?                                         \
  454             (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size   \
  455                 - ((m)->m_data + (m)->m_len) : 0) :                     \
  456             &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))
  457 
  458 /*
  459  * Arrange to prepend space of size plen to mbuf m.
  460  * If a new mbuf must be allocated, how specifies whether to wait.
  461  * If how is MB_DONTWAIT and allocation fails, the original mbuf chain
  462  * is freed and m is set to NULL.
  463  */
  464 #define M_PREPEND(m, plen, how) do {                                    \
  465         struct mbuf **_mmp = &(m);                                      \
  466         struct mbuf *_mm = *_mmp;                                       \
  467         int _mplen = (plen);                                            \
  468         int __mhow = (how);                                             \
  469                                                                         \
  470         if (M_LEADINGSPACE(_mm) >= _mplen) {                            \
  471                 _mm->m_data -= _mplen;                                  \
  472                 _mm->m_len += _mplen;                                   \
  473         } else                                                          \
  474                 _mm = m_prepend(_mm, _mplen, __mhow);                   \
  475         if (_mm != NULL && (_mm->m_flags & M_PKTHDR))                   \
  476                 _mm->m_pkthdr.len += _mplen;                            \
  477         *_mmp = _mm;                                                    \
  478 } while (0)
  479 
  480 /* Length to m_copy to copy all. */
  481 #define M_COPYALL       1000000000
  482 
  483 /* Compatibility with 4.3 */
  484 #define m_copy(m, o, l) m_copym((m), (o), (l), MB_DONTWAIT)
  485 
  486 #ifdef _KERNEL
  487 extern  u_int            m_clalloc_wid; /* mbuf cluster wait count */
  488 extern  u_int            m_mballoc_wid; /* mbuf wait count */
  489 extern  int              max_linkhdr;   /* largest link-level header */
  490 extern  int              max_protohdr;  /* largest protocol header */
  491 extern  int              max_hdr;       /* largest link+protocol header */
  492 extern  int              max_datalen;   /* MHLEN - max_hdr */
  493 extern  int              mbuf_wait;     /* mbuf sleep time */
  494 extern  int              nmbclusters;
  495 extern  int              nmbufs;
  496 
  497 struct uio;
  498 
  499 void             m_adj(struct mbuf *, int);
  500 void             m_align(struct mbuf *, int);
  501 int              m_apply(struct mbuf *, int, int,
  502                     int (*)(void *, void *, u_int), void *);
  503 int             m_append(struct mbuf *, int, c_caddr_t);
  504 void             m_cat(struct mbuf *, struct mbuf *);
  505 u_int            m_countm(struct mbuf *m, struct mbuf **lastm, u_int *mbcnt);
  506 void             m_copyback(struct mbuf *, int, int, caddr_t);
  507 void             m_copydata(const struct mbuf *, int, int, caddr_t);
  508 struct  mbuf    *m_copym(const struct mbuf *, int, int, int);
  509 struct  mbuf    *m_copypacket(struct mbuf *, int);
  510 struct  mbuf    *m_defrag(struct mbuf *, int);
  511 struct  mbuf    *m_defrag_nofree(struct mbuf *, int);
  512 struct  mbuf    *m_devget(char *, int, int, struct ifnet *,
  513                   void (*copy)(volatile const void *, volatile void *, size_t));
  514 struct  mbuf    *m_dup(struct mbuf *, int);
  515 struct  mbuf    *m_dup_data(struct mbuf *, int);
  516 int              m_dup_pkthdr(struct mbuf *, const struct mbuf *, int);
  517 void             m_extadd(struct mbuf *, caddr_t, u_int, void (*)(void *),
  518                   void (*)(void *), void *);
  519 #ifdef MBUF_DEBUG
  520 struct  mbuf    *_m_free(struct mbuf *, const char *name);
  521 void             _m_freem(struct mbuf *, const char *name);
  522 #else
  523 struct  mbuf    *m_free(struct mbuf *);
  524 void             m_freem(struct mbuf *);
  525 #endif
  526 struct  mbuf    *m_get(int, int);
  527 struct  mbuf    *m_getc(int len, int how, int type);
  528 struct  mbuf    *m_getcl(int how, short type, int flags);
  529 struct  mbuf    *m_getjcl(int how, short type, int flags, size_t size);
  530 struct  mbuf    *m_getclr(int, int);
  531 struct  mbuf    *m_gethdr(int, int);
  532 struct  mbuf    *m_getm(struct mbuf *, int, int, int);
  533 struct  mbuf    *m_getptr(struct mbuf *, int, int *);
  534 struct  mbuf    *m_last(struct mbuf *m);
  535 u_int            m_lengthm(struct mbuf *m, struct mbuf **lastm);
  536 void             m_move_pkthdr(struct mbuf *, struct mbuf *);
  537 struct  mbuf    *m_prepend(struct mbuf *, int, int);
  538 void             m_print(const struct mbuf *m);
  539 struct  mbuf    *m_pulldown(struct mbuf *, int, int, int *);
  540 struct  mbuf    *m_pullup(struct mbuf *, int);
  541 struct  mbuf    *m_split(struct mbuf *, int, int);
  542 struct  mbuf    *m_uiomove(struct uio *);
  543 struct  mbuf    *m_unshare(struct mbuf *, int);
  544 void            m_mclget(struct mbuf *m, int how);
  545 int             m_sharecount(struct mbuf *m);
  546 void            m_chtype(struct mbuf *m, int type);
  547 int             m_devpad(struct mbuf *m, int padto);
  548 
  549 #ifdef MBUF_DEBUG
  550 
  551 void            mbuftrackid(struct mbuf *, int);
  552 
  553 #define m_free(m)       _m_free(m, __func__)
  554 #define m_freem(m)      _m_freem(m, __func__)
  555 
  556 #else
  557 
  558 #define mbuftrackid(m, id)      /* empty */
  559 
  560 #endif
  561 
  562 /*
  563  * Allocate the right type of mbuf for the desired total length.
  564  * The mbuf returned does not necessarily cover the entire requested length.
  565  * This function follows mbuf chaining policy of allowing MINCLSIZE
  566  * amount of chained mbufs.
  567  */
  568 static __inline struct mbuf *
  569 m_getl(int len, int how, int type, int flags, int *psize)
  570 {
  571         struct mbuf *m;
  572         int size;
  573 
  574         if (len >= MINCLSIZE) {
  575                 m = m_getcl(how, type, flags);
  576                 size = MCLBYTES;
  577         } else if (flags & M_PKTHDR) {
  578                 m = m_gethdr(how, type);
  579                 size = MHLEN;
  580         } else {
  581                 m = m_get(how, type);
  582                 size = MLEN;
  583         }
  584         if (psize != NULL)
  585                 *psize = size;
  586         return (m);
  587 }
  588 
  589 static __inline struct mbuf *
  590 m_getlj(int len, int how, int type, int flags, int *psize)
  591 {
  592         if (len > MCLBYTES) {
  593                 struct mbuf *m;
  594 
  595                 m = m_getjcl(how, type, flags, MJUMPAGESIZE);
  596                 if (psize != NULL)
  597                         *psize = MJUMPAGESIZE;
  598                 return m;
  599         }
  600         return m_getl(len, how, type, flags, psize);
  601 }
  602 
  603 /*
  604  * Get a single mbuf that covers the requested number of bytes.
  605  * This function does not create mbuf chains.  It explicitly marks
  606  * places in the code that abuse mbufs for contiguous data buffers.
  607  */
  608 static __inline struct mbuf *
  609 m_getb(int len, int how, int type, int flags)
  610 {
  611         struct mbuf *m;
  612         int mbufsize = (flags & M_PKTHDR) ? MHLEN : MLEN;
  613 
  614         if (len > mbufsize)
  615                 m = m_getcl(how, type, flags);
  616         else if (flags & M_PKTHDR)
  617                 m = m_gethdr(how, type);
  618         else
  619                 m = m_get(how, type);
  620         return (m);
  621 }
  622 
  623 /*
  624  * Packets may have annotations attached by affixing a list
  625  * of "packet tags" to the pkthdr structure.  Packet tags are
  626  * dynamically allocated semi-opaque data structures that have
  627  * a fixed header (struct m_tag) that specifies the size of the
  628  * memory block and a <cookie,type> pair that identifies it.
  629  * The cookie is a 32-bit unique unsigned value used to identify
  630  * a module or ABI.  By convention this value is chose as the
  631  * date+time that the module is created, expressed as the number of
  632  * seconds since the epoch (e.g. using date -u +'%s').  The type value
  633  * is an ABI/module-specific value that identifies a particular annotation
  634  * and is private to the module.  For compatibility with systems
  635  * like openbsd that define packet tags w/o an ABI/module cookie,
  636  * the value PACKET_ABI_COMPAT is used to implement m_tag_get and
  637  * m_tag_find compatibility shim functions and several tag types are
  638  * defined below.  Users that do not require compatibility should use
  639  * a private cookie value so that packet tag-related definitions
  640  * can be maintained privately.
  641  *
  642  * Note that the packet tag returned by m_tag_alloc has the default
  643  * memory alignment implemented by kmalloc.  To reference private data
  644  * one can use a construct like:
  645  *
  646  *      struct m_tag *mtag = m_tag_alloc(...);
  647  *      struct foo *p = m_tag_data(mtag);
  648  *
  649  * if the alignment of struct m_tag is sufficient for referencing members
  650  * of struct foo.  Otherwise it is necessary to embed struct m_tag within
  651  * the private data structure to insure proper alignment; e.g.
  652  *
  653  *      struct foo {
  654  *              struct m_tag    tag;
  655  *              ...
  656  *      };
  657  *      struct foo *p = (struct foo *)m_tag_alloc(...);
  658  *      struct m_tag *mtag = &p->tag;
  659  */
  660 
  661 #define PACKET_TAG_NONE                         0  /* Nadda */
  662 
  663 /* Packet tag for use with PACKET_ABI_COMPAT */
  664 #define PACKET_TAG_IPSEC_IN_DONE                1  /* IPsec applied, in */
  665 /* struct tdb_indent */
  666 #define PACKET_TAG_IPSEC_OUT_DONE               2  /* IPsec applied, out */
  667 /* struct tdb_indent */
  668 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE         3  /* NIC IPsec crypto done */
  669 /* struct tdb_indent, never added */
  670 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED      4  /* NIC IPsec crypto req'ed */
  671 /* struct tdb_indent, never added */
  672 #define PACKET_TAG_IPSEC_PENDING_TDB            5  /* Reminder to do IPsec */
  673 /* struct tdb_indent, never added */
  674 #define PACKET_TAG_ENCAP                        6 /* Encap.  processing */
  675 /* struct ifnet *, the GIF interface */
  676 #define PACKET_TAG_IPSEC_HISTORY                7 /* IPSEC history */
  677 /* struct ipsec_history */
  678 #define PACKET_TAG_IPV6_INPUT                   8 /* IPV6 input processing */
  679 /* struct ip6aux */
  680 #define PACKET_TAG_IPFW_DIVERT                  9 /* divert info */
  681 /* struct divert_info */
  682 #define PACKET_TAG_DUMMYNET                     15 /* dummynet info */
  683 /* struct dn_pkt */
  684 #define PACKET_TAG_IPFORWARD                    18 /* ipforward info */
  685 /* struct sockaddr_in */
  686 #define PACKET_TAG_IPSRCRT                      27 /* IP srcrt opts */
  687 /* struct ip_srcrt_opt */
  688 #define PACKET_TAG_CARP                         28 /* CARP info */
  689 /* struct pf_mtag */
  690 #define PACKET_TAG_PF                           29 /* PF info */
  691 
  692 #define PACKET_TAG_PF_DIVERT                    0x0200 /* pf(4) diverted packet */
  693         
  694 
  695 /* Packet tag routines */
  696 struct  m_tag   *m_tag_alloc(uint32_t, int, int, int);
  697 void             m_tag_free(struct m_tag *);
  698 void             m_tag_prepend(struct mbuf *, struct m_tag *);
  699 void             m_tag_unlink(struct mbuf *, struct m_tag *);
  700 void             m_tag_delete(struct mbuf *, struct m_tag *);
  701 void             m_tag_delete_chain(struct mbuf *);
  702 struct  m_tag   *m_tag_locate(struct mbuf *, uint32_t, int, struct m_tag *);
  703 struct  m_tag   *m_tag_copy(struct m_tag *, int);
  704 int              m_tag_copy_chain(struct mbuf *, const struct mbuf *, int);
  705 void             m_tag_init(struct mbuf *);
  706 struct  m_tag   *m_tag_first(struct mbuf *);
  707 struct  m_tag   *m_tag_next(struct mbuf *, struct m_tag *);
  708 
  709 /* these are for openbsd compatibility */
  710 #define MTAG_ABI_COMPAT         0               /* compatibility ABI */
  711 
  712 static __inline void *
  713 m_tag_data(struct m_tag *tag)
  714 {
  715         return ((void *)(tag + 1));
  716 }
  717 
  718 static __inline struct m_tag *
  719 m_tag_get(int type, int length, int wait)
  720 {
  721         return m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait);
  722 }
  723 
  724 static __inline struct m_tag *
  725 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
  726 {
  727         return m_tag_locate(m, MTAG_ABI_COMPAT, type, start);
  728 }
  729 
  730 #endif  /* _KERNEL */
  731 
  732 #endif  /* _KERNEL || _KERNEL_STRUCTURES */
  733 #endif  /* !_SYS_MBUF_H_ */

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