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  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1988, 1993
    5  *      The Regents of the University of California.
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. Neither the name of the University nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  *
   32  *      @(#)mbuf.h      8.5 (Berkeley) 2/19/95
   33  * $FreeBSD: stable/12/sys/sys/mbuf.h 354438 2019-11-07 12:58:14Z hselasky $
   34  */
   35 
   36 #ifndef _SYS_MBUF_H_
   37 #define _SYS_MBUF_H_
   38 
   39 /* XXX: These includes suck. Sorry! */
   40 #include <sys/queue.h>
   41 #ifdef _KERNEL
   42 #include <sys/systm.h>
   43 #include <vm/uma.h>
   44 #ifdef WITNESS
   45 #include <sys/lock.h>
   46 #endif
   47 #endif
   48 
   49 #ifdef _KERNEL
   50 #include <sys/sdt.h>
   51 
   52 #define MBUF_PROBE1(probe, arg0)                                        \
   53         SDT_PROBE1(sdt, , , probe, arg0)
   54 #define MBUF_PROBE2(probe, arg0, arg1)                                  \
   55         SDT_PROBE2(sdt, , , probe, arg0, arg1)
   56 #define MBUF_PROBE3(probe, arg0, arg1, arg2)                            \
   57         SDT_PROBE3(sdt, , , probe, arg0, arg1, arg2)
   58 #define MBUF_PROBE4(probe, arg0, arg1, arg2, arg3)                      \
   59         SDT_PROBE4(sdt, , , probe, arg0, arg1, arg2, arg3)
   60 #define MBUF_PROBE5(probe, arg0, arg1, arg2, arg3, arg4)                \
   61         SDT_PROBE5(sdt, , , probe, arg0, arg1, arg2, arg3, arg4)
   62 
   63 SDT_PROBE_DECLARE(sdt, , , m__init);
   64 SDT_PROBE_DECLARE(sdt, , , m__gethdr);
   65 SDT_PROBE_DECLARE(sdt, , , m__get);
   66 SDT_PROBE_DECLARE(sdt, , , m__getcl);
   67 SDT_PROBE_DECLARE(sdt, , , m__clget);
   68 SDT_PROBE_DECLARE(sdt, , , m__cljget);
   69 SDT_PROBE_DECLARE(sdt, , , m__cljset);
   70 SDT_PROBE_DECLARE(sdt, , , m__free);
   71 SDT_PROBE_DECLARE(sdt, , , m__freem);
   72 
   73 #endif /* _KERNEL */
   74 
   75 /*
   76  * Mbufs are of a single size, MSIZE (sys/param.h), which includes overhead.
   77  * An mbuf may add a single "mbuf cluster" of size MCLBYTES (also in
   78  * sys/param.h), which has no additional overhead and is used instead of the
   79  * internal data area; this is done when at least MINCLSIZE of data must be
   80  * stored.  Additionally, it is possible to allocate a separate buffer
   81  * externally and attach it to the mbuf in a way similar to that of mbuf
   82  * clusters.
   83  *
   84  * NB: These calculation do not take actual compiler-induced alignment and
   85  * padding inside the complete struct mbuf into account.  Appropriate
   86  * attention is required when changing members of struct mbuf.
   87  *
   88  * MLEN is data length in a normal mbuf.
   89  * MHLEN is data length in an mbuf with pktheader.
   90  * MINCLSIZE is a smallest amount of data that should be put into cluster.
   91  *
   92  * Compile-time assertions in uipc_mbuf.c test these values to ensure that
   93  * they are sensible.
   94  */
   95 struct mbuf;
   96 #define MHSIZE          offsetof(struct mbuf, m_dat)
   97 #define MPKTHSIZE       offsetof(struct mbuf, m_pktdat)
   98 #define MLEN            ((int)(MSIZE - MHSIZE))
   99 #define MHLEN           ((int)(MSIZE - MPKTHSIZE))
  100 #define MINCLSIZE       (MHLEN + 1)
  101 
  102 #ifdef _KERNEL
  103 /*-
  104  * Macro for type conversion: convert mbuf pointer to data pointer of correct
  105  * type:
  106  *
  107  * mtod(m, t)   -- Convert mbuf pointer to data pointer of correct type.
  108  * mtodo(m, o) -- Same as above but with offset 'o' into data.
  109  */
  110 #define mtod(m, t)      ((t)((m)->m_data))
  111 #define mtodo(m, o)     ((void *)(((m)->m_data) + (o)))
  112 
  113 /*
  114  * Argument structure passed to UMA routines during mbuf and packet
  115  * allocations.
  116  */
  117 struct mb_args {
  118         int     flags;  /* Flags for mbuf being allocated */
  119         short   type;   /* Type of mbuf being allocated */
  120 };
  121 #endif /* _KERNEL */
  122 
  123 /*
  124  * Packet tag structure (see below for details).
  125  */
  126 struct m_tag {
  127         SLIST_ENTRY(m_tag)      m_tag_link;     /* List of packet tags */
  128         u_int16_t               m_tag_id;       /* Tag ID */
  129         u_int16_t               m_tag_len;      /* Length of data */
  130         u_int32_t               m_tag_cookie;   /* ABI/Module ID */
  131         void                    (*m_tag_free)(struct m_tag *);
  132 };
  133 
  134 /*
  135  * Static network interface owned tag.
  136  * Allocated through ifp->if_snd_tag_alloc().
  137  */
  138 struct m_snd_tag {
  139         struct ifnet *ifp;              /* network interface tag belongs to */
  140 };
  141 
  142 /*
  143  * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
  144  * Size ILP32: 48
  145  *       LP64: 56
  146  * Compile-time assertions in uipc_mbuf.c test these values to ensure that
  147  * they are correct.
  148  */
  149 struct pkthdr {
  150         union {
  151                 struct m_snd_tag *snd_tag;      /* send tag, if any */
  152                 struct ifnet    *rcvif;         /* rcv interface */
  153         };
  154         SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
  155         int32_t          len;           /* total packet length */
  156 
  157         /* Layer crossing persistent information. */
  158         uint32_t         flowid;        /* packet's 4-tuple system */
  159         uint32_t         csum_flags;    /* checksum and offload features */
  160         uint16_t         fibnum;        /* this packet should use this fib */
  161         uint8_t          cosqos;        /* class/quality of service */
  162         uint8_t          rsstype;       /* hash type */
  163         union {
  164                 uint64_t        rcv_tstmp;      /* timestamp in ns */
  165                 struct {
  166                         uint8_t          l2hlen;        /* layer 2 hdr len */
  167                         uint8_t          l3hlen;        /* layer 3 hdr len */
  168                         uint8_t          l4hlen;        /* layer 4 hdr len */
  169                         uint8_t          l5hlen;        /* layer 5 hdr len */
  170                         uint32_t         spare;
  171                 };
  172         };
  173         union {
  174                 uint8_t  eight[8];
  175                 uint16_t sixteen[4];
  176                 uint32_t thirtytwo[2];
  177                 uint64_t sixtyfour[1];
  178                 uintptr_t unintptr[1];
  179                 void    *ptr;
  180         } PH_per;
  181 
  182         /* Layer specific non-persistent local storage for reassembly, etc. */
  183         union {
  184                 uint8_t  eight[8];
  185                 uint16_t sixteen[4];
  186                 uint32_t thirtytwo[2];
  187                 uint64_t sixtyfour[1];
  188                 uintptr_t unintptr[1];
  189                 void    *ptr;
  190         } PH_loc;
  191 };
  192 #define ether_vtag      PH_per.sixteen[0]
  193 #define PH_vt           PH_per
  194 #define vt_nrecs        sixteen[0]
  195 #define tso_segsz       PH_per.sixteen[1]
  196 #define lro_nsegs       tso_segsz
  197 #define csum_phsum      PH_per.sixteen[2]
  198 #define csum_data       PH_per.thirtytwo[1]
  199 #define pace_thoff      PH_loc.sixteen[0]
  200 #define pace_tlen       PH_loc.sixteen[1]
  201 #define pace_drphdrlen  PH_loc.sixteen[2]
  202 #define pace_tos        PH_loc.eight[6]
  203 #define pace_lock       PH_loc.eight[7]
  204 
  205 /*
  206  * Description of external storage mapped into mbuf; valid only if M_EXT is
  207  * set.
  208  * Size ILP32: 28
  209  *       LP64: 48
  210  * Compile-time assertions in uipc_mbuf.c test these values to ensure that
  211  * they are correct.
  212  */
  213 typedef void m_ext_free_t(struct mbuf *);
  214 struct m_ext {
  215         union {
  216                 /*
  217                  * If EXT_FLAG_EMBREF is set, then we use refcount in the
  218                  * mbuf, the 'ext_count' member.  Otherwise, we have a
  219                  * shadow copy and we use pointer 'ext_cnt'.  The original
  220                  * mbuf is responsible to carry the pointer to free routine
  221                  * and its arguments.  They aren't copied into shadows in
  222                  * mb_dupcl() to avoid dereferencing next cachelines.
  223                  */
  224                 volatile u_int   ext_count;
  225                 volatile u_int  *ext_cnt;
  226         };
  227         char            *ext_buf;       /* start of buffer */
  228         uint32_t         ext_size;      /* size of buffer, for ext_free */
  229         uint32_t         ext_type:8,    /* type of external storage */
  230                          ext_flags:24;  /* external storage mbuf flags */
  231         /*
  232          * Fields below store the free context for the external storage.
  233          * They are valid only in the refcount carrying mbuf, the one with
  234          * EXT_FLAG_EMBREF flag, with exclusion for EXT_EXTREF type, where
  235          * the free context is copied into all mbufs that use same external
  236          * storage.
  237          */
  238 #define m_ext_copylen   offsetof(struct m_ext, ext_free)
  239         m_ext_free_t    *ext_free;      /* free routine if not the usual */
  240         void            *ext_arg1;      /* optional argument pointer */
  241         void            *ext_arg2;      /* optional argument pointer */
  242 };
  243 
  244 /*
  245  * The core of the mbuf object along with some shortcut defines for practical
  246  * purposes.
  247  */
  248 struct mbuf {
  249         /*
  250          * Header present at the beginning of every mbuf.
  251          * Size ILP32: 24
  252          *      LP64: 32
  253          * Compile-time assertions in uipc_mbuf.c test these values to ensure
  254          * that they are correct.
  255          */
  256         union { /* next buffer in chain */
  257                 struct mbuf             *m_next;
  258                 SLIST_ENTRY(mbuf)       m_slist;
  259                 STAILQ_ENTRY(mbuf)      m_stailq;
  260         };
  261         union { /* next chain in queue/record */
  262                 struct mbuf             *m_nextpkt;
  263                 SLIST_ENTRY(mbuf)       m_slistpkt;
  264                 STAILQ_ENTRY(mbuf)      m_stailqpkt;
  265         };
  266         caddr_t          m_data;        /* location of data */
  267         int32_t          m_len;         /* amount of data in this mbuf */
  268         uint32_t         m_type:8,      /* type of data in this mbuf */
  269                          m_flags:24;    /* flags; see below */
  270 #if !defined(__LP64__)
  271         uint32_t         m_pad;         /* pad for 64bit alignment */
  272 #endif
  273 
  274         /*
  275          * A set of optional headers (packet header, external storage header)
  276          * and internal data storage.  Historically, these arrays were sized
  277          * to MHLEN (space left after a packet header) and MLEN (space left
  278          * after only a regular mbuf header); they are now variable size in
  279          * order to support future work on variable-size mbufs.
  280          */
  281         union {
  282                 struct {
  283                         struct pkthdr   m_pkthdr;       /* M_PKTHDR set */
  284                         union {
  285                                 struct m_ext    m_ext;  /* M_EXT set */
  286                                 char            m_pktdat[0];
  287                         };
  288                 };
  289                 char    m_dat[0];                       /* !M_PKTHDR, !M_EXT */
  290         };
  291 };
  292 
  293 /*
  294  * mbuf flags of global significance and layer crossing.
  295  * Those of only protocol/layer specific significance are to be mapped
  296  * to M_PROTO[1-12] and cleared at layer handoff boundaries.
  297  * NB: Limited to the lower 24 bits.
  298  */
  299 #define M_EXT           0x00000001 /* has associated external storage */
  300 #define M_PKTHDR        0x00000002 /* start of record */
  301 #define M_EOR           0x00000004 /* end of record */
  302 #define M_RDONLY        0x00000008 /* associated data is marked read-only */
  303 #define M_BCAST         0x00000010 /* send/received as link-level broadcast */
  304 #define M_MCAST         0x00000020 /* send/received as link-level multicast */
  305 #define M_PROMISC       0x00000040 /* packet was not for us */
  306 #define M_VLANTAG       0x00000080 /* ether_vtag is valid */
  307 #define M_NOMAP         0x00000100 /* mbuf data is unmapped (soon from Drew) */
  308 #define M_NOFREE        0x00000200 /* do not free mbuf, embedded in cluster */
  309 #define M_TSTMP         0x00000400 /* rcv_tstmp field is valid */
  310 #define M_TSTMP_HPREC   0x00000800 /* rcv_tstmp is high-prec, typically
  311                                       hw-stamped on port (useful for IEEE 1588
  312                                       and 802.1AS) */
  313 
  314 #define M_PROTO1        0x00001000 /* protocol-specific */
  315 #define M_PROTO2        0x00002000 /* protocol-specific */
  316 #define M_PROTO3        0x00004000 /* protocol-specific */
  317 #define M_PROTO4        0x00008000 /* protocol-specific */
  318 #define M_PROTO5        0x00010000 /* protocol-specific */
  319 #define M_PROTO6        0x00020000 /* protocol-specific */
  320 #define M_PROTO7        0x00040000 /* protocol-specific */
  321 #define M_PROTO8        0x00080000 /* protocol-specific */
  322 #define M_PROTO9        0x00100000 /* protocol-specific */
  323 #define M_PROTO10       0x00200000 /* protocol-specific */
  324 #define M_PROTO11       0x00400000 /* protocol-specific */
  325 #define M_PROTO12       0x00800000 /* protocol-specific */
  326 
  327 #define MB_DTOR_SKIP    0x1     /* don't pollute the cache by touching a freed mbuf */
  328 
  329 /*
  330  * Flags to purge when crossing layers.
  331  */
  332 #define M_PROTOFLAGS \
  333     (M_PROTO1|M_PROTO2|M_PROTO3|M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8|\
  334      M_PROTO9|M_PROTO10|M_PROTO11|M_PROTO12)
  335 
  336 /*
  337  * Flags preserved when copying m_pkthdr.
  338  */
  339 #define M_COPYFLAGS \
  340     (M_PKTHDR|M_EOR|M_RDONLY|M_BCAST|M_MCAST|M_PROMISC|M_VLANTAG|M_TSTMP| \
  341      M_TSTMP_HPREC|M_PROTOFLAGS)
  342 
  343 /*
  344  * Mbuf flag description for use with printf(9) %b identifier.
  345  */
  346 #define M_FLAG_BITS \
  347     "\2\1M_EXT\2M_PKTHDR\3M_EOR\4M_RDONLY\5M_BCAST\6M_MCAST" \
  348     "\7M_PROMISC\10M_VLANTAG\13M_TSTMP\14M_TSTMP_HPREC"
  349 #define M_FLAG_PROTOBITS \
  350     "\15M_PROTO1\16M_PROTO2\17M_PROTO3\20M_PROTO4\21M_PROTO5" \
  351     "\22M_PROTO6\23M_PROTO7\24M_PROTO8\25M_PROTO9\26M_PROTO10" \
  352     "\27M_PROTO11\30M_PROTO12"
  353 #define M_FLAG_PRINTF (M_FLAG_BITS M_FLAG_PROTOBITS)
  354 
  355 /*
  356  * Network interface cards are able to hash protocol fields (such as IPv4
  357  * addresses and TCP port numbers) classify packets into flows.  These flows
  358  * can then be used to maintain ordering while delivering packets to the OS
  359  * via parallel input queues, as well as to provide a stateless affinity
  360  * model.  NIC drivers can pass up the hash via m->m_pkthdr.flowid, and set
  361  * m_flag fields to indicate how the hash should be interpreted by the
  362  * network stack.
  363  *
  364  * Most NICs support RSS, which provides ordering and explicit affinity, and
  365  * use the hash m_flag bits to indicate what header fields were covered by
  366  * the hash.  M_HASHTYPE_OPAQUE and M_HASHTYPE_OPAQUE_HASH can be set by non-
  367  * RSS cards or configurations that provide an opaque flow identifier, allowing
  368  * for ordering and distribution without explicit affinity.  Additionally,
  369  * M_HASHTYPE_OPAQUE_HASH indicates that the flow identifier has hash
  370  * properties.
  371  *
  372  * The meaning of the IPV6_EX suffix:
  373  * "o  Home address from the home address option in the IPv6 destination
  374  *     options header.  If the extension header is not present, use the Source
  375  *     IPv6 Address.
  376  *  o  IPv6 address that is contained in the Routing-Header-Type-2 from the
  377  *     associated extension header.  If the extension header is not present,
  378  *     use the Destination IPv6 Address."
  379  * Quoted from:
  380  * https://docs.microsoft.com/en-us/windows-hardware/drivers/network/rss-hashing-types#ndishashipv6ex
  381  */
  382 #define M_HASHTYPE_HASHPROP             0x80    /* has hash properties */
  383 #define M_HASHTYPE_HASH(t)              (M_HASHTYPE_HASHPROP | (t))
  384 /* Microsoft RSS standard hash types */
  385 #define M_HASHTYPE_NONE                 0
  386 #define M_HASHTYPE_RSS_IPV4             M_HASHTYPE_HASH(1) /* IPv4 2-tuple */
  387 #define M_HASHTYPE_RSS_TCP_IPV4         M_HASHTYPE_HASH(2) /* TCPv4 4-tuple */
  388 #define M_HASHTYPE_RSS_IPV6             M_HASHTYPE_HASH(3) /* IPv6 2-tuple */
  389 #define M_HASHTYPE_RSS_TCP_IPV6         M_HASHTYPE_HASH(4) /* TCPv6 4-tuple */
  390 #define M_HASHTYPE_RSS_IPV6_EX          M_HASHTYPE_HASH(5) /* IPv6 2-tuple +
  391                                                             * ext hdrs */
  392 #define M_HASHTYPE_RSS_TCP_IPV6_EX      M_HASHTYPE_HASH(6) /* TCPv6 4-tuple +
  393                                                             * ext hdrs */
  394 #define M_HASHTYPE_RSS_UDP_IPV4         M_HASHTYPE_HASH(7) /* IPv4 UDP 4-tuple*/
  395 #define M_HASHTYPE_RSS_UDP_IPV6         M_HASHTYPE_HASH(9) /* IPv6 UDP 4-tuple*/
  396 #define M_HASHTYPE_RSS_UDP_IPV6_EX      M_HASHTYPE_HASH(10)/* IPv6 UDP 4-tuple +
  397                                                             * ext hdrs */
  398 
  399 #define M_HASHTYPE_OPAQUE               63      /* ordering, not affinity */
  400 #define M_HASHTYPE_OPAQUE_HASH          M_HASHTYPE_HASH(M_HASHTYPE_OPAQUE)
  401                                                 /* ordering+hash, not affinity*/
  402 
  403 #define M_HASHTYPE_CLEAR(m)     ((m)->m_pkthdr.rsstype = 0)
  404 #define M_HASHTYPE_GET(m)       ((m)->m_pkthdr.rsstype)
  405 #define M_HASHTYPE_SET(m, v)    ((m)->m_pkthdr.rsstype = (v))
  406 #define M_HASHTYPE_TEST(m, v)   (M_HASHTYPE_GET(m) == (v))
  407 #define M_HASHTYPE_ISHASH(m)    (M_HASHTYPE_GET(m) & M_HASHTYPE_HASHPROP)
  408 
  409 /*
  410  * COS/QOS class and quality of service tags.
  411  * It uses DSCP code points as base.
  412  */
  413 #define QOS_DSCP_CS0            0x00
  414 #define QOS_DSCP_DEF            QOS_DSCP_CS0
  415 #define QOS_DSCP_CS1            0x20
  416 #define QOS_DSCP_AF11           0x28
  417 #define QOS_DSCP_AF12           0x30
  418 #define QOS_DSCP_AF13           0x38
  419 #define QOS_DSCP_CS2            0x40
  420 #define QOS_DSCP_AF21           0x48
  421 #define QOS_DSCP_AF22           0x50
  422 #define QOS_DSCP_AF23           0x58
  423 #define QOS_DSCP_CS3            0x60
  424 #define QOS_DSCP_AF31           0x68
  425 #define QOS_DSCP_AF32           0x70
  426 #define QOS_DSCP_AF33           0x78
  427 #define QOS_DSCP_CS4            0x80
  428 #define QOS_DSCP_AF41           0x88
  429 #define QOS_DSCP_AF42           0x90
  430 #define QOS_DSCP_AF43           0x98
  431 #define QOS_DSCP_CS5            0xa0
  432 #define QOS_DSCP_EF             0xb8
  433 #define QOS_DSCP_CS6            0xc0
  434 #define QOS_DSCP_CS7            0xe0
  435 
  436 /*
  437  * External mbuf storage buffer types.
  438  */
  439 #define EXT_CLUSTER     1       /* mbuf cluster */
  440 #define EXT_SFBUF       2       /* sendfile(2)'s sf_buf */
  441 #define EXT_JUMBOP      3       /* jumbo cluster page sized */
  442 #define EXT_JUMBO9      4       /* jumbo cluster 9216 bytes */
  443 #define EXT_JUMBO16     5       /* jumbo cluster 16184 bytes */
  444 #define EXT_PACKET      6       /* mbuf+cluster from packet zone */
  445 #define EXT_MBUF        7       /* external mbuf reference */
  446 
  447 #define EXT_VENDOR1     224     /* for vendor-internal use */
  448 #define EXT_VENDOR2     225     /* for vendor-internal use */
  449 #define EXT_VENDOR3     226     /* for vendor-internal use */
  450 #define EXT_VENDOR4     227     /* for vendor-internal use */
  451 
  452 #define EXT_EXP1        244     /* for experimental use */
  453 #define EXT_EXP2        245     /* for experimental use */
  454 #define EXT_EXP3        246     /* for experimental use */
  455 #define EXT_EXP4        247     /* for experimental use */
  456 
  457 #define EXT_NET_DRV     252     /* custom ext_buf provided by net driver(s) */
  458 #define EXT_MOD_TYPE    253     /* custom module's ext_buf type */
  459 #define EXT_DISPOSABLE  254     /* can throw this buffer away w/page flipping */
  460 #define EXT_EXTREF      255     /* has externally maintained ext_cnt ptr */
  461 
  462 /*
  463  * Flags for external mbuf buffer types.
  464  * NB: limited to the lower 24 bits.
  465  */
  466 #define EXT_FLAG_EMBREF         0x000001        /* embedded ext_count */
  467 #define EXT_FLAG_EXTREF         0x000002        /* external ext_cnt, notyet */
  468 
  469 #define EXT_FLAG_NOFREE         0x000010        /* don't free mbuf to pool, notyet */
  470 
  471 #define EXT_FLAG_VENDOR1        0x010000        /* These flags are vendor */
  472 #define EXT_FLAG_VENDOR2        0x020000        /* or submodule specific, */
  473 #define EXT_FLAG_VENDOR3        0x040000        /* not used by mbuf code. */
  474 #define EXT_FLAG_VENDOR4        0x080000        /* Set/read by submodule. */
  475 
  476 #define EXT_FLAG_EXP1           0x100000        /* for experimental use */
  477 #define EXT_FLAG_EXP2           0x200000        /* for experimental use */
  478 #define EXT_FLAG_EXP3           0x400000        /* for experimental use */
  479 #define EXT_FLAG_EXP4           0x800000        /* for experimental use */
  480 
  481 /*
  482  * EXT flag description for use with printf(9) %b identifier.
  483  */
  484 #define EXT_FLAG_BITS \
  485     "\2\1EXT_FLAG_EMBREF\2EXT_FLAG_EXTREF\5EXT_FLAG_NOFREE" \
  486     "\21EXT_FLAG_VENDOR1\22EXT_FLAG_VENDOR2\23EXT_FLAG_VENDOR3" \
  487     "\24EXT_FLAG_VENDOR4\25EXT_FLAG_EXP1\26EXT_FLAG_EXP2\27EXT_FLAG_EXP3" \
  488     "\30EXT_FLAG_EXP4"
  489 
  490 /*
  491  * Flags indicating checksum, segmentation and other offload work to be
  492  * done, or already done, by hardware or lower layers.  It is split into
  493  * separate inbound and outbound flags.
  494  *
  495  * Outbound flags that are set by upper protocol layers requesting lower
  496  * layers, or ideally the hardware, to perform these offloading tasks.
  497  * For outbound packets this field and its flags can be directly tested
  498  * against ifnet if_hwassist.
  499  */
  500 #define CSUM_IP                 0x00000001      /* IP header checksum offload */
  501 #define CSUM_IP_UDP             0x00000002      /* UDP checksum offload */
  502 #define CSUM_IP_TCP             0x00000004      /* TCP checksum offload */
  503 #define CSUM_IP_SCTP            0x00000008      /* SCTP checksum offload */
  504 #define CSUM_IP_TSO             0x00000010      /* TCP segmentation offload */
  505 #define CSUM_IP_ISCSI           0x00000020      /* iSCSI checksum offload */
  506 
  507 #define CSUM_IP6_UDP            0x00000200      /* UDP checksum offload */
  508 #define CSUM_IP6_TCP            0x00000400      /* TCP checksum offload */
  509 #define CSUM_IP6_SCTP           0x00000800      /* SCTP checksum offload */
  510 #define CSUM_IP6_TSO            0x00001000      /* TCP segmentation offload */
  511 #define CSUM_IP6_ISCSI          0x00002000      /* iSCSI checksum offload */
  512 
  513 /* Inbound checksum support where the checksum was verified by hardware. */
  514 #define CSUM_L3_CALC            0x01000000      /* calculated layer 3 csum */
  515 #define CSUM_L3_VALID           0x02000000      /* checksum is correct */
  516 #define CSUM_L4_CALC            0x04000000      /* calculated layer 4 csum */
  517 #define CSUM_L4_VALID           0x08000000      /* checksum is correct */
  518 #define CSUM_L5_CALC            0x10000000      /* calculated layer 5 csum */
  519 #define CSUM_L5_VALID           0x20000000      /* checksum is correct */
  520 #define CSUM_COALESCED          0x40000000      /* contains merged segments */
  521 
  522 #define CSUM_SND_TAG            0x80000000      /* Packet header has send tag */
  523 
  524 /*
  525  * CSUM flag description for use with printf(9) %b identifier.
  526  */
  527 #define CSUM_BITS \
  528     "\2\1CSUM_IP\2CSUM_IP_UDP\3CSUM_IP_TCP\4CSUM_IP_SCTP\5CSUM_IP_TSO" \
  529     "\6CSUM_IP_ISCSI" \
  530     "\12CSUM_IP6_UDP\13CSUM_IP6_TCP\14CSUM_IP6_SCTP\15CSUM_IP6_TSO" \
  531     "\16CSUM_IP6_ISCSI" \
  532     "\31CSUM_L3_CALC\32CSUM_L3_VALID\33CSUM_L4_CALC\34CSUM_L4_VALID" \
  533     "\35CSUM_L5_CALC\36CSUM_L5_VALID\37CSUM_COALESCED\40CSUM_SND_TAG"
  534 
  535 /* CSUM flags compatibility mappings. */
  536 #define CSUM_IP_CHECKED         CSUM_L3_CALC
  537 #define CSUM_IP_VALID           CSUM_L3_VALID
  538 #define CSUM_DATA_VALID         CSUM_L4_VALID
  539 #define CSUM_PSEUDO_HDR         CSUM_L4_CALC
  540 #define CSUM_SCTP_VALID         CSUM_L4_VALID
  541 #define CSUM_DELAY_DATA         (CSUM_TCP|CSUM_UDP)
  542 #define CSUM_DELAY_IP           CSUM_IP         /* Only v4, no v6 IP hdr csum */
  543 #define CSUM_DELAY_DATA_IPV6    (CSUM_TCP_IPV6|CSUM_UDP_IPV6)
  544 #define CSUM_DATA_VALID_IPV6    CSUM_DATA_VALID
  545 #define CSUM_TCP                CSUM_IP_TCP
  546 #define CSUM_UDP                CSUM_IP_UDP
  547 #define CSUM_SCTP               CSUM_IP_SCTP
  548 #define CSUM_TSO                (CSUM_IP_TSO|CSUM_IP6_TSO)
  549 #define CSUM_UDP_IPV6           CSUM_IP6_UDP
  550 #define CSUM_TCP_IPV6           CSUM_IP6_TCP
  551 #define CSUM_SCTP_IPV6          CSUM_IP6_SCTP
  552 
  553 /*
  554  * mbuf types describing the content of the mbuf (including external storage).
  555  */
  556 #define MT_NOTMBUF      0       /* USED INTERNALLY ONLY! Object is not mbuf */
  557 #define MT_DATA         1       /* dynamic (data) allocation */
  558 #define MT_HEADER       MT_DATA /* packet header, use M_PKTHDR instead */
  559 
  560 #define MT_VENDOR1      4       /* for vendor-internal use */
  561 #define MT_VENDOR2      5       /* for vendor-internal use */
  562 #define MT_VENDOR3      6       /* for vendor-internal use */
  563 #define MT_VENDOR4      7       /* for vendor-internal use */
  564 
  565 #define MT_SONAME       8       /* socket name */
  566 
  567 #define MT_EXP1         9       /* for experimental use */
  568 #define MT_EXP2         10      /* for experimental use */
  569 #define MT_EXP3         11      /* for experimental use */
  570 #define MT_EXP4         12      /* for experimental use */
  571 
  572 #define MT_CONTROL      14      /* extra-data protocol message */
  573 #define MT_EXTCONTROL   15      /* control message with externalized contents */
  574 #define MT_OOBDATA      16      /* expedited data  */
  575 
  576 #define MT_NOINIT       255     /* Not a type but a flag to allocate
  577                                    a non-initialized mbuf */
  578 
  579 /*
  580  * String names of mbuf-related UMA(9) and malloc(9) types.  Exposed to
  581  * !_KERNEL so that monitoring tools can look up the zones with
  582  * libmemstat(3).
  583  */
  584 #define MBUF_MEM_NAME           "mbuf"
  585 #define MBUF_CLUSTER_MEM_NAME   "mbuf_cluster"
  586 #define MBUF_PACKET_MEM_NAME    "mbuf_packet"
  587 #define MBUF_JUMBOP_MEM_NAME    "mbuf_jumbo_page"
  588 #define MBUF_JUMBO9_MEM_NAME    "mbuf_jumbo_9k"
  589 #define MBUF_JUMBO16_MEM_NAME   "mbuf_jumbo_16k"
  590 #define MBUF_TAG_MEM_NAME       "mbuf_tag"
  591 #define MBUF_EXTREFCNT_MEM_NAME "mbuf_ext_refcnt"
  592 
  593 #ifdef _KERNEL
  594 
  595 #ifdef WITNESS
  596 #define MBUF_CHECKSLEEP(how) do {                                       \
  597         if (how == M_WAITOK)                                            \
  598                 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,         \
  599                     "Sleeping in \"%s\"", __func__);                    \
  600 } while (0)
  601 #else
  602 #define MBUF_CHECKSLEEP(how)
  603 #endif
  604 
  605 /*
  606  * Network buffer allocation API
  607  *
  608  * The rest of it is defined in kern/kern_mbuf.c
  609  */
  610 extern uma_zone_t       zone_mbuf;
  611 extern uma_zone_t       zone_clust;
  612 extern uma_zone_t       zone_pack;
  613 extern uma_zone_t       zone_jumbop;
  614 extern uma_zone_t       zone_jumbo9;
  615 extern uma_zone_t       zone_jumbo16;
  616 
  617 void             mb_dupcl(struct mbuf *, struct mbuf *);
  618 void             mb_free_ext(struct mbuf *);
  619 void             m_adj(struct mbuf *, int);
  620 int              m_apply(struct mbuf *, int, int,
  621                     int (*)(void *, void *, u_int), void *);
  622 int              m_append(struct mbuf *, int, c_caddr_t);
  623 void             m_cat(struct mbuf *, struct mbuf *);
  624 void             m_catpkt(struct mbuf *, struct mbuf *);
  625 int              m_clget(struct mbuf *m, int how);
  626 void            *m_cljget(struct mbuf *m, int how, int size);
  627 struct mbuf     *m_collapse(struct mbuf *, int, int);
  628 void             m_copyback(struct mbuf *, int, int, c_caddr_t);
  629 void             m_copydata(const struct mbuf *, int, int, caddr_t);
  630 struct mbuf     *m_copym(struct mbuf *, int, int, int);
  631 struct mbuf     *m_copypacket(struct mbuf *, int);
  632 void             m_copy_pkthdr(struct mbuf *, struct mbuf *);
  633 struct mbuf     *m_copyup(struct mbuf *, int, int);
  634 struct mbuf     *m_defrag(struct mbuf *, int);
  635 void             m_demote_pkthdr(struct mbuf *);
  636 void             m_demote(struct mbuf *, int, int);
  637 struct mbuf     *m_devget(char *, int, int, struct ifnet *,
  638                     void (*)(char *, caddr_t, u_int));
  639 void             m_dispose_extcontrolm(struct mbuf *m);
  640 struct mbuf     *m_dup(const struct mbuf *, int);
  641 int              m_dup_pkthdr(struct mbuf *, const struct mbuf *, int);
  642 void             m_extadd(struct mbuf *, char *, u_int, m_ext_free_t,
  643                     void *, void *, int, int);
  644 u_int            m_fixhdr(struct mbuf *);
  645 struct mbuf     *m_fragment(struct mbuf *, int, int);
  646 void             m_freem(struct mbuf *);
  647 struct mbuf     *m_get2(int, int, short, int);
  648 struct mbuf     *m_getjcl(int, short, int, int);
  649 struct mbuf     *m_getm2(struct mbuf *, int, int, short, int);
  650 struct mbuf     *m_getptr(struct mbuf *, int, int *);
  651 u_int            m_length(struct mbuf *, struct mbuf **);
  652 int              m_mbuftouio(struct uio *, const struct mbuf *, int);
  653 void             m_move_pkthdr(struct mbuf *, struct mbuf *);
  654 int              m_pkthdr_init(struct mbuf *, int);
  655 struct mbuf     *m_prepend(struct mbuf *, int, int);
  656 void             m_print(const struct mbuf *, int);
  657 struct mbuf     *m_pulldown(struct mbuf *, int, int, int *);
  658 struct mbuf     *m_pullup(struct mbuf *, int);
  659 int              m_sanity(struct mbuf *, int);
  660 struct mbuf     *m_split(struct mbuf *, int, int);
  661 struct mbuf     *m_uiotombuf(struct uio *, int, int, int, int);
  662 struct mbuf     *m_unshare(struct mbuf *, int);
  663 
  664 static __inline int
  665 m_gettype(int size)
  666 {
  667         int type;
  668 
  669         switch (size) {
  670         case MSIZE:
  671                 type = EXT_MBUF;
  672                 break;
  673         case MCLBYTES:
  674                 type = EXT_CLUSTER;
  675                 break;
  676 #if MJUMPAGESIZE != MCLBYTES
  677         case MJUMPAGESIZE:
  678                 type = EXT_JUMBOP;
  679                 break;
  680 #endif
  681         case MJUM9BYTES:
  682                 type = EXT_JUMBO9;
  683                 break;
  684         case MJUM16BYTES:
  685                 type = EXT_JUMBO16;
  686                 break;
  687         default:
  688                 panic("%s: invalid cluster size %d", __func__, size);
  689         }
  690 
  691         return (type);
  692 }
  693 
  694 /*
  695  * Associated an external reference counted buffer with an mbuf.
  696  */
  697 static __inline void
  698 m_extaddref(struct mbuf *m, char *buf, u_int size, u_int *ref_cnt,
  699     m_ext_free_t freef, void *arg1, void *arg2)
  700 {
  701 
  702         KASSERT(ref_cnt != NULL, ("%s: ref_cnt not provided", __func__));
  703 
  704         atomic_add_int(ref_cnt, 1);
  705         m->m_flags |= M_EXT;
  706         m->m_ext.ext_buf = buf;
  707         m->m_ext.ext_cnt = ref_cnt;
  708         m->m_data = m->m_ext.ext_buf;
  709         m->m_ext.ext_size = size;
  710         m->m_ext.ext_free = freef;
  711         m->m_ext.ext_arg1 = arg1;
  712         m->m_ext.ext_arg2 = arg2;
  713         m->m_ext.ext_type = EXT_EXTREF;
  714         m->m_ext.ext_flags = 0;
  715 }
  716 
  717 static __inline uma_zone_t
  718 m_getzone(int size)
  719 {
  720         uma_zone_t zone;
  721 
  722         switch (size) {
  723         case MCLBYTES:
  724                 zone = zone_clust;
  725                 break;
  726 #if MJUMPAGESIZE != MCLBYTES
  727         case MJUMPAGESIZE:
  728                 zone = zone_jumbop;
  729                 break;
  730 #endif
  731         case MJUM9BYTES:
  732                 zone = zone_jumbo9;
  733                 break;
  734         case MJUM16BYTES:
  735                 zone = zone_jumbo16;
  736                 break;
  737         default:
  738                 panic("%s: invalid cluster size %d", __func__, size);
  739         }
  740 
  741         return (zone);
  742 }
  743 
  744 /*
  745  * Initialize an mbuf with linear storage.
  746  *
  747  * Inline because the consumer text overhead will be roughly the same to
  748  * initialize or call a function with this many parameters and M_PKTHDR
  749  * should go away with constant propagation for !MGETHDR.
  750  */
  751 static __inline int
  752 m_init(struct mbuf *m, int how, short type, int flags)
  753 {
  754         int error;
  755 
  756         m->m_next = NULL;
  757         m->m_nextpkt = NULL;
  758         m->m_data = m->m_dat;
  759         m->m_len = 0;
  760         m->m_flags = flags;
  761         m->m_type = type;
  762         if (flags & M_PKTHDR)
  763                 error = m_pkthdr_init(m, how);
  764         else
  765                 error = 0;
  766 
  767         MBUF_PROBE5(m__init, m, how, type, flags, error);
  768         return (error);
  769 }
  770 
  771 static __inline struct mbuf *
  772 m_get(int how, short type)
  773 {
  774         struct mbuf *m;
  775         struct mb_args args;
  776 
  777         args.flags = 0;
  778         args.type = type;
  779         m = uma_zalloc_arg(zone_mbuf, &args, how);
  780         MBUF_PROBE3(m__get, how, type, m);
  781         return (m);
  782 }
  783 
  784 static __inline struct mbuf *
  785 m_gethdr(int how, short type)
  786 {
  787         struct mbuf *m;
  788         struct mb_args args;
  789 
  790         args.flags = M_PKTHDR;
  791         args.type = type;
  792         m = uma_zalloc_arg(zone_mbuf, &args, how);
  793         MBUF_PROBE3(m__gethdr, how, type, m);
  794         return (m);
  795 }
  796 
  797 static __inline struct mbuf *
  798 m_getcl(int how, short type, int flags)
  799 {
  800         struct mbuf *m;
  801         struct mb_args args;
  802 
  803         args.flags = flags;
  804         args.type = type;
  805         m = uma_zalloc_arg(zone_pack, &args, how);
  806         MBUF_PROBE4(m__getcl, how, type, flags, m);
  807         return (m);
  808 }
  809 
  810 /*
  811  * XXX: m_cljset() is a dangerous API.  One must attach only a new,
  812  * unreferenced cluster to an mbuf(9).  It is not possible to assert
  813  * that, so care can be taken only by users of the API.
  814  */
  815 static __inline void
  816 m_cljset(struct mbuf *m, void *cl, int type)
  817 {
  818         int size;
  819 
  820         switch (type) {
  821         case EXT_CLUSTER:
  822                 size = MCLBYTES;
  823                 break;
  824 #if MJUMPAGESIZE != MCLBYTES
  825         case EXT_JUMBOP:
  826                 size = MJUMPAGESIZE;
  827                 break;
  828 #endif
  829         case EXT_JUMBO9:
  830                 size = MJUM9BYTES;
  831                 break;
  832         case EXT_JUMBO16:
  833                 size = MJUM16BYTES;
  834                 break;
  835         default:
  836                 panic("%s: unknown cluster type %d", __func__, type);
  837                 break;
  838         }
  839 
  840         m->m_data = m->m_ext.ext_buf = cl;
  841         m->m_ext.ext_free = m->m_ext.ext_arg1 = m->m_ext.ext_arg2 = NULL;
  842         m->m_ext.ext_size = size;
  843         m->m_ext.ext_type = type;
  844         m->m_ext.ext_flags = EXT_FLAG_EMBREF;
  845         m->m_ext.ext_count = 1;
  846         m->m_flags |= M_EXT;
  847         MBUF_PROBE3(m__cljset, m, cl, type);
  848 }
  849 
  850 static __inline void
  851 m_chtype(struct mbuf *m, short new_type)
  852 {
  853 
  854         m->m_type = new_type;
  855 }
  856 
  857 static __inline void
  858 m_clrprotoflags(struct mbuf *m)
  859 {
  860 
  861         while (m) {
  862                 m->m_flags &= ~M_PROTOFLAGS;
  863                 m = m->m_next;
  864         }
  865 }
  866 
  867 static __inline struct mbuf *
  868 m_last(struct mbuf *m)
  869 {
  870 
  871         while (m->m_next)
  872                 m = m->m_next;
  873         return (m);
  874 }
  875 
  876 static inline u_int
  877 m_extrefcnt(struct mbuf *m)
  878 {
  879 
  880         KASSERT(m->m_flags & M_EXT, ("%s: M_EXT missing", __func__));
  881 
  882         return ((m->m_ext.ext_flags & EXT_FLAG_EMBREF) ? m->m_ext.ext_count :
  883             *m->m_ext.ext_cnt);
  884 }
  885 
  886 /*
  887  * mbuf, cluster, and external object allocation macros (for compatibility
  888  * purposes).
  889  */
  890 #define M_MOVE_PKTHDR(to, from) m_move_pkthdr((to), (from))
  891 #define MGET(m, how, type)      ((m) = m_get((how), (type)))
  892 #define MGETHDR(m, how, type)   ((m) = m_gethdr((how), (type)))
  893 #define MCLGET(m, how)          m_clget((m), (how))
  894 #define MEXTADD(m, buf, size, free, arg1, arg2, flags, type)            \
  895     m_extadd((m), (char *)(buf), (size), (free), (arg1), (arg2),        \
  896     (flags), (type))
  897 #define m_getm(m, len, how, type)                                       \
  898     m_getm2((m), (len), (how), (type), M_PKTHDR)
  899 
  900 /*
  901  * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
  902  * be both the local data payload, or an external buffer area, depending on
  903  * whether M_EXT is set).
  904  */
  905 #define M_WRITABLE(m)   (!((m)->m_flags & M_RDONLY) &&                  \
  906                          (!(((m)->m_flags & M_EXT)) ||                  \
  907                          (m_extrefcnt(m) == 1)))
  908 
  909 /* Check if the supplied mbuf has a packet header, or else panic. */
  910 #define M_ASSERTPKTHDR(m)                                               \
  911         KASSERT((m) != NULL && (m)->m_flags & M_PKTHDR,                 \
  912             ("%s: no mbuf packet header!", __func__))
  913 
  914 /*
  915  * Ensure that the supplied mbuf is a valid, non-free mbuf.
  916  *
  917  * XXX: Broken at the moment.  Need some UMA magic to make it work again.
  918  */
  919 #define M_ASSERTVALID(m)                                                \
  920         KASSERT((((struct mbuf *)m)->m_flags & 0) == 0,                 \
  921             ("%s: attempted use of a free mbuf!", __func__))
  922 
  923 /*
  924  * Return the address of the start of the buffer associated with an mbuf,
  925  * handling external storage, packet-header mbufs, and regular data mbufs.
  926  */
  927 #define M_START(m)                                                      \
  928         (((m)->m_flags & M_EXT) ? (m)->m_ext.ext_buf :                  \
  929          ((m)->m_flags & M_PKTHDR) ? &(m)->m_pktdat[0] :                \
  930          &(m)->m_dat[0])
  931 
  932 /*
  933  * Return the size of the buffer associated with an mbuf, handling external
  934  * storage, packet-header mbufs, and regular data mbufs.
  935  */
  936 #define M_SIZE(m)                                                       \
  937         (((m)->m_flags & M_EXT) ? (m)->m_ext.ext_size :                 \
  938          ((m)->m_flags & M_PKTHDR) ? MHLEN :                            \
  939          MLEN)
  940 
  941 /*
  942  * Set the m_data pointer of a newly allocated mbuf to place an object of the
  943  * specified size at the end of the mbuf, longword aligned.
  944  *
  945  * NB: Historically, we had M_ALIGN(), MH_ALIGN(), and MEXT_ALIGN() as
  946  * separate macros, each asserting that it was called at the proper moment.
  947  * This required callers to themselves test the storage type and call the
  948  * right one.  Rather than require callers to be aware of those layout
  949  * decisions, we centralize here.
  950  */
  951 static __inline void
  952 m_align(struct mbuf *m, int len)
  953 {
  954 #ifdef INVARIANTS
  955         const char *msg = "%s: not a virgin mbuf";
  956 #endif
  957         int adjust;
  958 
  959         KASSERT(m->m_data == M_START(m), (msg, __func__));
  960 
  961         adjust = M_SIZE(m) - len;
  962         m->m_data += adjust &~ (sizeof(long)-1);
  963 }
  964 
  965 #define M_ALIGN(m, len)         m_align(m, len)
  966 #define MH_ALIGN(m, len)        m_align(m, len)
  967 #define MEXT_ALIGN(m, len)      m_align(m, len)
  968 
  969 /*
  970  * Compute the amount of space available before the current start of data in
  971  * an mbuf.
  972  *
  973  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  974  * of checking writability of the mbuf data area rests solely with the caller.
  975  *
  976  * NB: In previous versions, M_LEADINGSPACE() would only check M_WRITABLE()
  977  * for mbufs with external storage.  We now allow mbuf-embedded data to be
  978  * read-only as well.
  979  */
  980 #define M_LEADINGSPACE(m)                                               \
  981         (M_WRITABLE(m) ? ((m)->m_data - M_START(m)) : 0)
  982 
  983 /*
  984  * Compute the amount of space available after the end of data in an mbuf.
  985  *
  986  * The M_WRITABLE() is a temporary, conservative safety measure: the burden
  987  * of checking writability of the mbuf data area rests solely with the caller.
  988  *
  989  * NB: In previous versions, M_TRAILINGSPACE() would only check M_WRITABLE()
  990  * for mbufs with external storage.  We now allow mbuf-embedded data to be
  991  * read-only as well.
  992  */
  993 #define M_TRAILINGSPACE(m)                                              \
  994         (M_WRITABLE(m) ?                                                \
  995             ((M_START(m) + M_SIZE(m)) - ((m)->m_data + (m)->m_len)) : 0)
  996 
  997 /*
  998  * Arrange to prepend space of size plen to mbuf m.  If a new mbuf must be
  999  * allocated, how specifies whether to wait.  If the allocation fails, the
 1000  * original mbuf chain is freed and m is set to NULL.
 1001  */
 1002 #define M_PREPEND(m, plen, how) do {                                    \
 1003         struct mbuf **_mmp = &(m);                                      \
 1004         struct mbuf *_mm = *_mmp;                                       \
 1005         int _mplen = (plen);                                            \
 1006         int __mhow = (how);                                             \
 1007                                                                         \
 1008         MBUF_CHECKSLEEP(how);                                           \
 1009         if (M_LEADINGSPACE(_mm) >= _mplen) {                            \
 1010                 _mm->m_data -= _mplen;                                  \
 1011                 _mm->m_len += _mplen;                                   \
 1012         } else                                                          \
 1013                 _mm = m_prepend(_mm, _mplen, __mhow);                   \
 1014         if (_mm != NULL && _mm->m_flags & M_PKTHDR)                     \
 1015                 _mm->m_pkthdr.len += _mplen;                            \
 1016         *_mmp = _mm;                                                    \
 1017 } while (0)
 1018 
 1019 /*
 1020  * Change mbuf to new type.  This is a relatively expensive operation and
 1021  * should be avoided.
 1022  */
 1023 #define MCHTYPE(m, t)   m_chtype((m), (t))
 1024 
 1025 /* Length to m_copy to copy all. */
 1026 #define M_COPYALL       1000000000
 1027 
 1028 extern int              max_datalen;    /* MHLEN - max_hdr */
 1029 extern int              max_hdr;        /* Largest link + protocol header */
 1030 extern int              max_linkhdr;    /* Largest link-level header */
 1031 extern int              max_protohdr;   /* Largest protocol header */
 1032 extern int              nmbclusters;    /* Maximum number of clusters */
 1033 
 1034 /*-
 1035  * Network packets may have annotations attached by affixing a list of
 1036  * "packet tags" to the pkthdr structure.  Packet tags are dynamically
 1037  * allocated semi-opaque data structures that have a fixed header
 1038  * (struct m_tag) that specifies the size of the memory block and a
 1039  * <cookie,type> pair that identifies it.  The cookie is a 32-bit unique
 1040  * unsigned value used to identify a module or ABI.  By convention this value
 1041  * is chosen as the date+time that the module is created, expressed as the
 1042  * number of seconds since the epoch (e.g., using date -u +'%s').  The type
 1043  * value is an ABI/module-specific value that identifies a particular
 1044  * annotation and is private to the module.  For compatibility with systems
 1045  * like OpenBSD that define packet tags w/o an ABI/module cookie, the value
 1046  * PACKET_ABI_COMPAT is used to implement m_tag_get and m_tag_find
 1047  * compatibility shim functions and several tag types are defined below.
 1048  * Users that do not require compatibility should use a private cookie value
 1049  * so that packet tag-related definitions can be maintained privately.
 1050  *
 1051  * Note that the packet tag returned by m_tag_alloc has the default memory
 1052  * alignment implemented by malloc.  To reference private data one can use a
 1053  * construct like:
 1054  *
 1055  *      struct m_tag *mtag = m_tag_alloc(...);
 1056  *      struct foo *p = (struct foo *)(mtag+1);
 1057  *
 1058  * if the alignment of struct m_tag is sufficient for referencing members of
 1059  * struct foo.  Otherwise it is necessary to embed struct m_tag within the
 1060  * private data structure to insure proper alignment; e.g.,
 1061  *
 1062  *      struct foo {
 1063  *              struct m_tag    tag;
 1064  *              ...
 1065  *      };
 1066  *      struct foo *p = (struct foo *) m_tag_alloc(...);
 1067  *      struct m_tag *mtag = &p->tag;
 1068  */
 1069 
 1070 /*
 1071  * Persistent tags stay with an mbuf until the mbuf is reclaimed.  Otherwise
 1072  * tags are expected to ``vanish'' when they pass through a network
 1073  * interface.  For most interfaces this happens normally as the tags are
 1074  * reclaimed when the mbuf is free'd.  However in some special cases
 1075  * reclaiming must be done manually.  An example is packets that pass through
 1076  * the loopback interface.  Also, one must be careful to do this when
 1077  * ``turning around'' packets (e.g., icmp_reflect).
 1078  *
 1079  * To mark a tag persistent bit-or this flag in when defining the tag id.
 1080  * The tag will then be treated as described above.
 1081  */
 1082 #define MTAG_PERSISTENT                         0x800
 1083 
 1084 #define PACKET_TAG_NONE                         0  /* Nadda */
 1085 
 1086 /* Packet tags for use with PACKET_ABI_COMPAT. */
 1087 #define PACKET_TAG_IPSEC_IN_DONE                1  /* IPsec applied, in */
 1088 #define PACKET_TAG_IPSEC_OUT_DONE               2  /* IPsec applied, out */
 1089 #define PACKET_TAG_IPSEC_IN_CRYPTO_DONE         3  /* NIC IPsec crypto done */
 1090 #define PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED      4  /* NIC IPsec crypto req'ed */
 1091 #define PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO     5  /* NIC notifies IPsec */
 1092 #define PACKET_TAG_IPSEC_PENDING_TDB            6  /* Reminder to do IPsec */
 1093 #define PACKET_TAG_BRIDGE                       7  /* Bridge processing done */
 1094 #define PACKET_TAG_GIF                          8  /* GIF processing done */
 1095 #define PACKET_TAG_GRE                          9  /* GRE processing done */
 1096 #define PACKET_TAG_IN_PACKET_CHECKSUM           10 /* NIC checksumming done */
 1097 #define PACKET_TAG_ENCAP                        11 /* Encap.  processing */
 1098 #define PACKET_TAG_IPSEC_SOCKET                 12 /* IPSEC socket ref */
 1099 #define PACKET_TAG_IPSEC_HISTORY                13 /* IPSEC history */
 1100 #define PACKET_TAG_IPV6_INPUT                   14 /* IPV6 input processing */
 1101 #define PACKET_TAG_DUMMYNET                     15 /* dummynet info */
 1102 #define PACKET_TAG_DIVERT                       17 /* divert info */
 1103 #define PACKET_TAG_IPFORWARD                    18 /* ipforward info */
 1104 #define PACKET_TAG_MACLABEL     (19 | MTAG_PERSISTENT) /* MAC label */
 1105 #define PACKET_TAG_PF           (21 | MTAG_PERSISTENT) /* PF/ALTQ information */
 1106 #define PACKET_TAG_RTSOCKFAM                    25 /* rtsock sa family */
 1107 #define PACKET_TAG_IPOPTIONS                    27 /* Saved IP options */
 1108 #define PACKET_TAG_CARP                         28 /* CARP info */
 1109 #define PACKET_TAG_IPSEC_NAT_T_PORTS            29 /* two uint16_t */
 1110 #define PACKET_TAG_ND_OUTGOING                  30 /* ND outgoing */
 1111 
 1112 /* Specific cookies and tags. */
 1113 
 1114 /* Packet tag routines. */
 1115 struct m_tag    *m_tag_alloc(u_int32_t, int, int, int);
 1116 void             m_tag_delete(struct mbuf *, struct m_tag *);
 1117 void             m_tag_delete_chain(struct mbuf *, struct m_tag *);
 1118 void             m_tag_free_default(struct m_tag *);
 1119 struct m_tag    *m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
 1120 struct m_tag    *m_tag_copy(struct m_tag *, int);
 1121 int              m_tag_copy_chain(struct mbuf *, const struct mbuf *, int);
 1122 void             m_tag_delete_nonpersistent(struct mbuf *);
 1123 
 1124 /*
 1125  * Initialize the list of tags associated with an mbuf.
 1126  */
 1127 static __inline void
 1128 m_tag_init(struct mbuf *m)
 1129 {
 1130 
 1131         SLIST_INIT(&m->m_pkthdr.tags);
 1132 }
 1133 
 1134 /*
 1135  * Set up the contents of a tag.  Note that this does not fill in the free
 1136  * method; the caller is expected to do that.
 1137  *
 1138  * XXX probably should be called m_tag_init, but that was already taken.
 1139  */
 1140 static __inline void
 1141 m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
 1142 {
 1143 
 1144         t->m_tag_id = type;
 1145         t->m_tag_len = len;
 1146         t->m_tag_cookie = cookie;
 1147 }
 1148 
 1149 /*
 1150  * Reclaim resources associated with a tag.
 1151  */
 1152 static __inline void
 1153 m_tag_free(struct m_tag *t)
 1154 {
 1155 
 1156         (*t->m_tag_free)(t);
 1157 }
 1158 
 1159 /*
 1160  * Return the first tag associated with an mbuf.
 1161  */
 1162 static __inline struct m_tag *
 1163 m_tag_first(struct mbuf *m)
 1164 {
 1165 
 1166         return (SLIST_FIRST(&m->m_pkthdr.tags));
 1167 }
 1168 
 1169 /*
 1170  * Return the next tag in the list of tags associated with an mbuf.
 1171  */
 1172 static __inline struct m_tag *
 1173 m_tag_next(struct mbuf *m __unused, struct m_tag *t)
 1174 {
 1175 
 1176         return (SLIST_NEXT(t, m_tag_link));
 1177 }
 1178 
 1179 /*
 1180  * Prepend a tag to the list of tags associated with an mbuf.
 1181  */
 1182 static __inline void
 1183 m_tag_prepend(struct mbuf *m, struct m_tag *t)
 1184 {
 1185 
 1186         SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
 1187 }
 1188 
 1189 /*
 1190  * Unlink a tag from the list of tags associated with an mbuf.
 1191  */
 1192 static __inline void
 1193 m_tag_unlink(struct mbuf *m, struct m_tag *t)
 1194 {
 1195 
 1196         SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
 1197 }
 1198 
 1199 /* These are for OpenBSD compatibility. */
 1200 #define MTAG_ABI_COMPAT         0               /* compatibility ABI */
 1201 
 1202 static __inline struct m_tag *
 1203 m_tag_get(int type, int length, int wait)
 1204 {
 1205         return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
 1206 }
 1207 
 1208 static __inline struct m_tag *
 1209 m_tag_find(struct mbuf *m, int type, struct m_tag *start)
 1210 {
 1211         return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL :
 1212             m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
 1213 }
 1214 
 1215 static __inline struct mbuf *
 1216 m_free(struct mbuf *m)
 1217 {
 1218         struct mbuf *n = m->m_next;
 1219 
 1220         MBUF_PROBE1(m__free, m);
 1221         if ((m->m_flags & (M_PKTHDR|M_NOFREE)) == (M_PKTHDR|M_NOFREE))
 1222                 m_tag_delete_chain(m, NULL);
 1223         if (m->m_flags & M_EXT)
 1224                 mb_free_ext(m);
 1225         else if ((m->m_flags & M_NOFREE) == 0)
 1226                 uma_zfree(zone_mbuf, m);
 1227         return (n);
 1228 }
 1229 
 1230 static __inline int
 1231 rt_m_getfib(struct mbuf *m)
 1232 {
 1233         KASSERT(m->m_flags & M_PKTHDR , ("Attempt to get FIB from non header mbuf."));
 1234         return (m->m_pkthdr.fibnum);
 1235 }
 1236 
 1237 #define M_GETFIB(_m)   rt_m_getfib(_m)
 1238 
 1239 #define M_SETFIB(_m, _fib) do {                                         \
 1240         KASSERT((_m)->m_flags & M_PKTHDR, ("Attempt to set FIB on non header mbuf."));  \
 1241         ((_m)->m_pkthdr.fibnum) = (_fib);                               \
 1242 } while (0)
 1243 
 1244 /* flags passed as first argument for "m_ether_tcpip_hash()" */
 1245 #define MBUF_HASHFLAG_L2        (1 << 2)
 1246 #define MBUF_HASHFLAG_L3        (1 << 3)
 1247 #define MBUF_HASHFLAG_L4        (1 << 4)
 1248 
 1249 /* mbuf hashing helper routines */
 1250 uint32_t        m_ether_tcpip_hash_init(void);
 1251 uint32_t        m_ether_tcpip_hash(const uint32_t, const struct mbuf *, const uint32_t);
 1252 
 1253 #ifdef MBUF_PROFILING
 1254  void m_profile(struct mbuf *m);
 1255  #define M_PROFILE(m) m_profile(m)
 1256 #else
 1257  #define M_PROFILE(m)
 1258 #endif
 1259 
 1260 struct mbufq {
 1261         STAILQ_HEAD(, mbuf)     mq_head;
 1262         int                     mq_len;
 1263         int                     mq_maxlen;
 1264 };
 1265 
 1266 static inline void
 1267 mbufq_init(struct mbufq *mq, int maxlen)
 1268 {
 1269 
 1270         STAILQ_INIT(&mq->mq_head);
 1271         mq->mq_maxlen = maxlen;
 1272         mq->mq_len = 0;
 1273 }
 1274 
 1275 static inline struct mbuf *
 1276 mbufq_flush(struct mbufq *mq)
 1277 {
 1278         struct mbuf *m;
 1279 
 1280         m = STAILQ_FIRST(&mq->mq_head);
 1281         STAILQ_INIT(&mq->mq_head);
 1282         mq->mq_len = 0;
 1283         return (m);
 1284 }
 1285 
 1286 static inline void
 1287 mbufq_drain(struct mbufq *mq)
 1288 {
 1289         struct mbuf *m, *n;
 1290 
 1291         n = mbufq_flush(mq);
 1292         while ((m = n) != NULL) {
 1293                 n = STAILQ_NEXT(m, m_stailqpkt);
 1294                 m_freem(m);
 1295         }
 1296 }
 1297 
 1298 static inline struct mbuf *
 1299 mbufq_first(const struct mbufq *mq)
 1300 {
 1301 
 1302         return (STAILQ_FIRST(&mq->mq_head));
 1303 }
 1304 
 1305 static inline struct mbuf *
 1306 mbufq_last(const struct mbufq *mq)
 1307 {
 1308 
 1309         return (STAILQ_LAST(&mq->mq_head, mbuf, m_stailqpkt));
 1310 }
 1311 
 1312 static inline int
 1313 mbufq_full(const struct mbufq *mq)
 1314 {
 1315 
 1316         return (mq->mq_len >= mq->mq_maxlen);
 1317 }
 1318 
 1319 static inline int
 1320 mbufq_len(const struct mbufq *mq)
 1321 {
 1322 
 1323         return (mq->mq_len);
 1324 }
 1325 
 1326 static inline int
 1327 mbufq_enqueue(struct mbufq *mq, struct mbuf *m)
 1328 {
 1329 
 1330         if (mbufq_full(mq))
 1331                 return (ENOBUFS);
 1332         STAILQ_INSERT_TAIL(&mq->mq_head, m, m_stailqpkt);
 1333         mq->mq_len++;
 1334         return (0);
 1335 }
 1336 
 1337 static inline struct mbuf *
 1338 mbufq_dequeue(struct mbufq *mq)
 1339 {
 1340         struct mbuf *m;
 1341 
 1342         m = STAILQ_FIRST(&mq->mq_head);
 1343         if (m) {
 1344                 STAILQ_REMOVE_HEAD(&mq->mq_head, m_stailqpkt);
 1345                 m->m_nextpkt = NULL;
 1346                 mq->mq_len--;
 1347         }
 1348         return (m);
 1349 }
 1350 
 1351 static inline void
 1352 mbufq_prepend(struct mbufq *mq, struct mbuf *m)
 1353 {
 1354 
 1355         STAILQ_INSERT_HEAD(&mq->mq_head, m, m_stailqpkt);
 1356         mq->mq_len++;
 1357 }
 1358 
 1359 /*
 1360  * Note: this doesn't enforce the maximum list size for dst.
 1361  */
 1362 static inline void
 1363 mbufq_concat(struct mbufq *mq_dst, struct mbufq *mq_src)
 1364 {
 1365 
 1366         mq_dst->mq_len += mq_src->mq_len;
 1367         STAILQ_CONCAT(&mq_dst->mq_head, &mq_src->mq_head);
 1368         mq_src->mq_len = 0;
 1369 }
 1370 
 1371 #ifdef _SYS_TIMESPEC_H_
 1372 static inline void
 1373 mbuf_tstmp2timespec(struct mbuf *m, struct timespec *ts)
 1374 {
 1375 
 1376         KASSERT((m->m_flags & M_PKTHDR) != 0, ("mbuf %p no M_PKTHDR", m));
 1377         KASSERT((m->m_flags & M_TSTMP) != 0, ("mbuf %p no M_TSTMP", m));
 1378         ts->tv_sec = m->m_pkthdr.rcv_tstmp / 1000000000;
 1379         ts->tv_nsec = m->m_pkthdr.rcv_tstmp % 1000000000;
 1380 }
 1381 #endif
 1382 
 1383 #ifdef NETDUMP
 1384 /* Invoked from the netdump client code. */
 1385 void    netdump_mbuf_drain(void);
 1386 void    netdump_mbuf_dump(void);
 1387 void    netdump_mbuf_reinit(int nmbuf, int nclust, int clsize);
 1388 #endif
 1389 
 1390 #endif /* _KERNEL */
 1391 #endif /* !_SYS_MBUF_H_ */

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