The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/uipc_mbuf.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1982, 1986, 1988, 1991, 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. Neither the name of the University nor the names of its contributors
   16  *    may be used to endorse or promote products derived from this software
   17  *    without specific prior written permission.
   18  *
   19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   29  * SUCH DAMAGE.
   30  *
   31  *      @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
   32  */
   33 
   34 #include <sys/cdefs.h>
   35 __FBSDID("$FreeBSD: releng/12.0/sys/kern/uipc_mbuf.c 334054 2018-05-22 15:54:25Z fabient $");
   36 
   37 #include "opt_param.h"
   38 #include "opt_mbuf_stress_test.h"
   39 #include "opt_mbuf_profiling.h"
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/kernel.h>
   44 #include <sys/limits.h>
   45 #include <sys/lock.h>
   46 #include <sys/malloc.h>
   47 #include <sys/mbuf.h>
   48 #include <sys/sysctl.h>
   49 #include <sys/domain.h>
   50 #include <sys/protosw.h>
   51 #include <sys/uio.h>
   52 #include <sys/sdt.h>
   53 
   54 SDT_PROBE_DEFINE5_XLATE(sdt, , , m__init,
   55     "struct mbuf *", "mbufinfo_t *",
   56     "uint32_t", "uint32_t",
   57     "uint16_t", "uint16_t",
   58     "uint32_t", "uint32_t",
   59     "uint32_t", "uint32_t");
   60 
   61 SDT_PROBE_DEFINE3_XLATE(sdt, , , m__gethdr,
   62     "uint32_t", "uint32_t",
   63     "uint16_t", "uint16_t",
   64     "struct mbuf *", "mbufinfo_t *");
   65 
   66 SDT_PROBE_DEFINE3_XLATE(sdt, , , m__get,
   67     "uint32_t", "uint32_t",
   68     "uint16_t", "uint16_t",
   69     "struct mbuf *", "mbufinfo_t *");
   70 
   71 SDT_PROBE_DEFINE4_XLATE(sdt, , , m__getcl,
   72     "uint32_t", "uint32_t",
   73     "uint16_t", "uint16_t",
   74     "uint32_t", "uint32_t",
   75     "struct mbuf *", "mbufinfo_t *");
   76 
   77 SDT_PROBE_DEFINE3_XLATE(sdt, , , m__clget,
   78     "struct mbuf *", "mbufinfo_t *",
   79     "uint32_t", "uint32_t",
   80     "uint32_t", "uint32_t");
   81 
   82 SDT_PROBE_DEFINE4_XLATE(sdt, , , m__cljget,
   83     "struct mbuf *", "mbufinfo_t *",
   84     "uint32_t", "uint32_t",
   85     "uint32_t", "uint32_t",
   86     "void*", "void*");
   87 
   88 SDT_PROBE_DEFINE(sdt, , , m__cljset);
   89 
   90 SDT_PROBE_DEFINE1_XLATE(sdt, , , m__free,
   91         "struct mbuf *", "mbufinfo_t *");
   92 
   93 SDT_PROBE_DEFINE1_XLATE(sdt, , , m__freem,
   94     "struct mbuf *", "mbufinfo_t *");
   95 
   96 #include <security/mac/mac_framework.h>
   97 
   98 int     max_linkhdr;
   99 int     max_protohdr;
  100 int     max_hdr;
  101 int     max_datalen;
  102 #ifdef MBUF_STRESS_TEST
  103 int     m_defragpackets;
  104 int     m_defragbytes;
  105 int     m_defraguseless;
  106 int     m_defragfailure;
  107 int     m_defragrandomfailures;
  108 #endif
  109 
  110 /*
  111  * sysctl(8) exported objects
  112  */
  113 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RD,
  114            &max_linkhdr, 0, "Size of largest link layer header");
  115 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RD,
  116            &max_protohdr, 0, "Size of largest protocol layer header");
  117 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RD,
  118            &max_hdr, 0, "Size of largest link plus protocol header");
  119 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RD,
  120            &max_datalen, 0, "Minimum space left in mbuf after max_hdr");
  121 #ifdef MBUF_STRESS_TEST
  122 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
  123            &m_defragpackets, 0, "");
  124 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
  125            &m_defragbytes, 0, "");
  126 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
  127            &m_defraguseless, 0, "");
  128 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
  129            &m_defragfailure, 0, "");
  130 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
  131            &m_defragrandomfailures, 0, "");
  132 #endif
  133 
  134 /*
  135  * Ensure the correct size of various mbuf parameters.  It could be off due
  136  * to compiler-induced padding and alignment artifacts.
  137  */
  138 CTASSERT(MSIZE - offsetof(struct mbuf, m_dat) == MLEN);
  139 CTASSERT(MSIZE - offsetof(struct mbuf, m_pktdat) == MHLEN);
  140 
  141 /*
  142  * mbuf data storage should be 64-bit aligned regardless of architectural
  143  * pointer size; check this is the case with and without a packet header.
  144  */
  145 CTASSERT(offsetof(struct mbuf, m_dat) % 8 == 0);
  146 CTASSERT(offsetof(struct mbuf, m_pktdat) % 8 == 0);
  147 
  148 /*
  149  * While the specific values here don't matter too much (i.e., +/- a few
  150  * words), we do want to ensure that changes to these values are carefully
  151  * reasoned about and properly documented.  This is especially the case as
  152  * network-protocol and device-driver modules encode these layouts, and must
  153  * be recompiled if the structures change.  Check these values at compile time
  154  * against the ones documented in comments in mbuf.h.
  155  *
  156  * NB: Possibly they should be documented there via #define's and not just
  157  * comments.
  158  */
  159 #if defined(__LP64__)
  160 CTASSERT(offsetof(struct mbuf, m_dat) == 32);
  161 CTASSERT(sizeof(struct pkthdr) == 56);
  162 CTASSERT(sizeof(struct m_ext) == 48);
  163 #else
  164 CTASSERT(offsetof(struct mbuf, m_dat) == 24);
  165 CTASSERT(sizeof(struct pkthdr) == 48);
  166 CTASSERT(sizeof(struct m_ext) == 28);
  167 #endif
  168 
  169 /*
  170  * Assert that the queue(3) macros produce code of the same size as an old
  171  * plain pointer does.
  172  */
  173 #ifdef INVARIANTS
  174 static struct mbuf __used m_assertbuf;
  175 CTASSERT(sizeof(m_assertbuf.m_slist) == sizeof(m_assertbuf.m_next));
  176 CTASSERT(sizeof(m_assertbuf.m_stailq) == sizeof(m_assertbuf.m_next));
  177 CTASSERT(sizeof(m_assertbuf.m_slistpkt) == sizeof(m_assertbuf.m_nextpkt));
  178 CTASSERT(sizeof(m_assertbuf.m_stailqpkt) == sizeof(m_assertbuf.m_nextpkt));
  179 #endif
  180 
  181 /*
  182  * Attach the cluster from *m to *n, set up m_ext in *n
  183  * and bump the refcount of the cluster.
  184  */
  185 void
  186 mb_dupcl(struct mbuf *n, struct mbuf *m)
  187 {
  188         volatile u_int *refcnt;
  189 
  190         KASSERT(m->m_flags & M_EXT, ("%s: M_EXT not set on %p", __func__, m));
  191         KASSERT(!(n->m_flags & M_EXT), ("%s: M_EXT set on %p", __func__, n));
  192 
  193         /*
  194          * Cache access optimization.  For most kinds of external
  195          * storage we don't need full copy of m_ext, since the
  196          * holder of the 'ext_count' is responsible to carry the
  197          * free routine and its arguments.  Exclusion is EXT_EXTREF,
  198          * where 'ext_cnt' doesn't point into mbuf at all.
  199          */
  200         if (m->m_ext.ext_type == EXT_EXTREF)
  201                 bcopy(&m->m_ext, &n->m_ext, sizeof(struct m_ext));
  202         else
  203                 bcopy(&m->m_ext, &n->m_ext, m_ext_copylen);
  204         n->m_flags |= M_EXT;
  205         n->m_flags |= m->m_flags & M_RDONLY;
  206 
  207         /* See if this is the mbuf that holds the embedded refcount. */
  208         if (m->m_ext.ext_flags & EXT_FLAG_EMBREF) {
  209                 refcnt = n->m_ext.ext_cnt = &m->m_ext.ext_count;
  210                 n->m_ext.ext_flags &= ~EXT_FLAG_EMBREF;
  211         } else {
  212                 KASSERT(m->m_ext.ext_cnt != NULL,
  213                     ("%s: no refcounting pointer on %p", __func__, m));
  214                 refcnt = m->m_ext.ext_cnt;
  215         }
  216 
  217         if (*refcnt == 1)
  218                 *refcnt += 1;
  219         else
  220                 atomic_add_int(refcnt, 1);
  221 }
  222 
  223 void
  224 m_demote_pkthdr(struct mbuf *m)
  225 {
  226 
  227         M_ASSERTPKTHDR(m);
  228 
  229         m_tag_delete_chain(m, NULL);
  230         m->m_flags &= ~M_PKTHDR;
  231         bzero(&m->m_pkthdr, sizeof(struct pkthdr));
  232 }
  233 
  234 /*
  235  * Clean up mbuf (chain) from any tags and packet headers.
  236  * If "all" is set then the first mbuf in the chain will be
  237  * cleaned too.
  238  */
  239 void
  240 m_demote(struct mbuf *m0, int all, int flags)
  241 {
  242         struct mbuf *m;
  243 
  244         for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) {
  245                 KASSERT(m->m_nextpkt == NULL, ("%s: m_nextpkt in m %p, m0 %p",
  246                     __func__, m, m0));
  247                 if (m->m_flags & M_PKTHDR)
  248                         m_demote_pkthdr(m);
  249                 m->m_flags = m->m_flags & (M_EXT | M_RDONLY | M_NOFREE | flags);
  250         }
  251 }
  252 
  253 /*
  254  * Sanity checks on mbuf (chain) for use in KASSERT() and general
  255  * debugging.
  256  * Returns 0 or panics when bad and 1 on all tests passed.
  257  * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they
  258  * blow up later.
  259  */
  260 int
  261 m_sanity(struct mbuf *m0, int sanitize)
  262 {
  263         struct mbuf *m;
  264         caddr_t a, b;
  265         int pktlen = 0;
  266 
  267 #ifdef INVARIANTS
  268 #define M_SANITY_ACTION(s)      panic("mbuf %p: " s, m)
  269 #else
  270 #define M_SANITY_ACTION(s)      printf("mbuf %p: " s, m)
  271 #endif
  272 
  273         for (m = m0; m != NULL; m = m->m_next) {
  274                 /*
  275                  * Basic pointer checks.  If any of these fails then some
  276                  * unrelated kernel memory before or after us is trashed.
  277                  * No way to recover from that.
  278                  */
  279                 a = M_START(m);
  280                 b = a + M_SIZE(m);
  281                 if ((caddr_t)m->m_data < a)
  282                         M_SANITY_ACTION("m_data outside mbuf data range left");
  283                 if ((caddr_t)m->m_data > b)
  284                         M_SANITY_ACTION("m_data outside mbuf data range right");
  285                 if ((caddr_t)m->m_data + m->m_len > b)
  286                         M_SANITY_ACTION("m_data + m_len exeeds mbuf space");
  287 
  288                 /* m->m_nextpkt may only be set on first mbuf in chain. */
  289                 if (m != m0 && m->m_nextpkt != NULL) {
  290                         if (sanitize) {
  291                                 m_freem(m->m_nextpkt);
  292                                 m->m_nextpkt = (struct mbuf *)0xDEADC0DE;
  293                         } else
  294                                 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf");
  295                 }
  296 
  297                 /* packet length (not mbuf length!) calculation */
  298                 if (m0->m_flags & M_PKTHDR)
  299                         pktlen += m->m_len;
  300 
  301                 /* m_tags may only be attached to first mbuf in chain. */
  302                 if (m != m0 && m->m_flags & M_PKTHDR &&
  303                     !SLIST_EMPTY(&m->m_pkthdr.tags)) {
  304                         if (sanitize) {
  305                                 m_tag_delete_chain(m, NULL);
  306                                 /* put in 0xDEADC0DE perhaps? */
  307                         } else
  308                                 M_SANITY_ACTION("m_tags on in-chain mbuf");
  309                 }
  310 
  311                 /* M_PKTHDR may only be set on first mbuf in chain */
  312                 if (m != m0 && m->m_flags & M_PKTHDR) {
  313                         if (sanitize) {
  314                                 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr));
  315                                 m->m_flags &= ~M_PKTHDR;
  316                                 /* put in 0xDEADCODE and leave hdr flag in */
  317                         } else
  318                                 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf");
  319                 }
  320         }
  321         m = m0;
  322         if (pktlen && pktlen != m->m_pkthdr.len) {
  323                 if (sanitize)
  324                         m->m_pkthdr.len = 0;
  325                 else
  326                         M_SANITY_ACTION("m_pkthdr.len != mbuf chain length");
  327         }
  328         return 1;
  329 
  330 #undef  M_SANITY_ACTION
  331 }
  332 
  333 /*
  334  * Non-inlined part of m_init().
  335  */
  336 int
  337 m_pkthdr_init(struct mbuf *m, int how)
  338 {
  339 #ifdef MAC
  340         int error;
  341 #endif
  342         m->m_data = m->m_pktdat;
  343         bzero(&m->m_pkthdr, sizeof(m->m_pkthdr));
  344 #ifdef MAC
  345         /* If the label init fails, fail the alloc */
  346         error = mac_mbuf_init(m, how);
  347         if (error)
  348                 return (error);
  349 #endif
  350 
  351         return (0);
  352 }
  353 
  354 /*
  355  * "Move" mbuf pkthdr from "from" to "to".
  356  * "from" must have M_PKTHDR set, and "to" must be empty.
  357  */
  358 void
  359 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
  360 {
  361 
  362 #if 0
  363         /* see below for why these are not enabled */
  364         M_ASSERTPKTHDR(to);
  365         /* Note: with MAC, this may not be a good assertion. */
  366         KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags),
  367             ("m_move_pkthdr: to has tags"));
  368 #endif
  369 #ifdef MAC
  370         /*
  371          * XXXMAC: It could be this should also occur for non-MAC?
  372          */
  373         if (to->m_flags & M_PKTHDR)
  374                 m_tag_delete_chain(to, NULL);
  375 #endif
  376         to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
  377         if ((to->m_flags & M_EXT) == 0)
  378                 to->m_data = to->m_pktdat;
  379         to->m_pkthdr = from->m_pkthdr;          /* especially tags */
  380         SLIST_INIT(&from->m_pkthdr.tags);       /* purge tags from src */
  381         from->m_flags &= ~M_PKTHDR;
  382 }
  383 
  384 /*
  385  * Duplicate "from"'s mbuf pkthdr in "to".
  386  * "from" must have M_PKTHDR set, and "to" must be empty.
  387  * In particular, this does a deep copy of the packet tags.
  388  */
  389 int
  390 m_dup_pkthdr(struct mbuf *to, const struct mbuf *from, int how)
  391 {
  392 
  393 #if 0
  394         /*
  395          * The mbuf allocator only initializes the pkthdr
  396          * when the mbuf is allocated with m_gethdr(). Many users
  397          * (e.g. m_copy*, m_prepend) use m_get() and then
  398          * smash the pkthdr as needed causing these
  399          * assertions to trip.  For now just disable them.
  400          */
  401         M_ASSERTPKTHDR(to);
  402         /* Note: with MAC, this may not be a good assertion. */
  403         KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags"));
  404 #endif
  405         MBUF_CHECKSLEEP(how);
  406 #ifdef MAC
  407         if (to->m_flags & M_PKTHDR)
  408                 m_tag_delete_chain(to, NULL);
  409 #endif
  410         to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
  411         if ((to->m_flags & M_EXT) == 0)
  412                 to->m_data = to->m_pktdat;
  413         to->m_pkthdr = from->m_pkthdr;
  414         SLIST_INIT(&to->m_pkthdr.tags);
  415         return (m_tag_copy_chain(to, from, how));
  416 }
  417 
  418 /*
  419  * Lesser-used path for M_PREPEND:
  420  * allocate new mbuf to prepend to chain,
  421  * copy junk along.
  422  */
  423 struct mbuf *
  424 m_prepend(struct mbuf *m, int len, int how)
  425 {
  426         struct mbuf *mn;
  427 
  428         if (m->m_flags & M_PKTHDR)
  429                 mn = m_gethdr(how, m->m_type);
  430         else
  431                 mn = m_get(how, m->m_type);
  432         if (mn == NULL) {
  433                 m_freem(m);
  434                 return (NULL);
  435         }
  436         if (m->m_flags & M_PKTHDR)
  437                 m_move_pkthdr(mn, m);
  438         mn->m_next = m;
  439         m = mn;
  440         if (len < M_SIZE(m))
  441                 M_ALIGN(m, len);
  442         m->m_len = len;
  443         return (m);
  444 }
  445 
  446 /*
  447  * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
  448  * continuing for "len" bytes.  If len is M_COPYALL, copy to end of mbuf.
  449  * The wait parameter is a choice of M_WAITOK/M_NOWAIT from caller.
  450  * Note that the copy is read-only, because clusters are not copied,
  451  * only their reference counts are incremented.
  452  */
  453 struct mbuf *
  454 m_copym(struct mbuf *m, int off0, int len, int wait)
  455 {
  456         struct mbuf *n, **np;
  457         int off = off0;
  458         struct mbuf *top;
  459         int copyhdr = 0;
  460 
  461         KASSERT(off >= 0, ("m_copym, negative off %d", off));
  462         KASSERT(len >= 0, ("m_copym, negative len %d", len));
  463         MBUF_CHECKSLEEP(wait);
  464         if (off == 0 && m->m_flags & M_PKTHDR)
  465                 copyhdr = 1;
  466         while (off > 0) {
  467                 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
  468                 if (off < m->m_len)
  469                         break;
  470                 off -= m->m_len;
  471                 m = m->m_next;
  472         }
  473         np = &top;
  474         top = NULL;
  475         while (len > 0) {
  476                 if (m == NULL) {
  477                         KASSERT(len == M_COPYALL,
  478                             ("m_copym, length > size of mbuf chain"));
  479                         break;
  480                 }
  481                 if (copyhdr)
  482                         n = m_gethdr(wait, m->m_type);
  483                 else
  484                         n = m_get(wait, m->m_type);
  485                 *np = n;
  486                 if (n == NULL)
  487                         goto nospace;
  488                 if (copyhdr) {
  489                         if (!m_dup_pkthdr(n, m, wait))
  490                                 goto nospace;
  491                         if (len == M_COPYALL)
  492                                 n->m_pkthdr.len -= off0;
  493                         else
  494                                 n->m_pkthdr.len = len;
  495                         copyhdr = 0;
  496                 }
  497                 n->m_len = min(len, m->m_len - off);
  498                 if (m->m_flags & M_EXT) {
  499                         n->m_data = m->m_data + off;
  500                         mb_dupcl(n, m);
  501                 } else
  502                         bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
  503                             (u_int)n->m_len);
  504                 if (len != M_COPYALL)
  505                         len -= n->m_len;
  506                 off = 0;
  507                 m = m->m_next;
  508                 np = &n->m_next;
  509         }
  510 
  511         return (top);
  512 nospace:
  513         m_freem(top);
  514         return (NULL);
  515 }
  516 
  517 /*
  518  * Copy an entire packet, including header (which must be present).
  519  * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
  520  * Note that the copy is read-only, because clusters are not copied,
  521  * only their reference counts are incremented.
  522  * Preserve alignment of the first mbuf so if the creator has left
  523  * some room at the beginning (e.g. for inserting protocol headers)
  524  * the copies still have the room available.
  525  */
  526 struct mbuf *
  527 m_copypacket(struct mbuf *m, int how)
  528 {
  529         struct mbuf *top, *n, *o;
  530 
  531         MBUF_CHECKSLEEP(how);
  532         n = m_get(how, m->m_type);
  533         top = n;
  534         if (n == NULL)
  535                 goto nospace;
  536 
  537         if (!m_dup_pkthdr(n, m, how))
  538                 goto nospace;
  539         n->m_len = m->m_len;
  540         if (m->m_flags & M_EXT) {
  541                 n->m_data = m->m_data;
  542                 mb_dupcl(n, m);
  543         } else {
  544                 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
  545                 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
  546         }
  547 
  548         m = m->m_next;
  549         while (m) {
  550                 o = m_get(how, m->m_type);
  551                 if (o == NULL)
  552                         goto nospace;
  553 
  554                 n->m_next = o;
  555                 n = n->m_next;
  556 
  557                 n->m_len = m->m_len;
  558                 if (m->m_flags & M_EXT) {
  559                         n->m_data = m->m_data;
  560                         mb_dupcl(n, m);
  561                 } else {
  562                         bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
  563                 }
  564 
  565                 m = m->m_next;
  566         }
  567         return top;
  568 nospace:
  569         m_freem(top);
  570         return (NULL);
  571 }
  572 
  573 /*
  574  * Copy data from an mbuf chain starting "off" bytes from the beginning,
  575  * continuing for "len" bytes, into the indicated buffer.
  576  */
  577 void
  578 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
  579 {
  580         u_int count;
  581 
  582         KASSERT(off >= 0, ("m_copydata, negative off %d", off));
  583         KASSERT(len >= 0, ("m_copydata, negative len %d", len));
  584         while (off > 0) {
  585                 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
  586                 if (off < m->m_len)
  587                         break;
  588                 off -= m->m_len;
  589                 m = m->m_next;
  590         }
  591         while (len > 0) {
  592                 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
  593                 count = min(m->m_len - off, len);
  594                 bcopy(mtod(m, caddr_t) + off, cp, count);
  595                 len -= count;
  596                 cp += count;
  597                 off = 0;
  598                 m = m->m_next;
  599         }
  600 }
  601 
  602 /*
  603  * Copy a packet header mbuf chain into a completely new chain, including
  604  * copying any mbuf clusters.  Use this instead of m_copypacket() when
  605  * you need a writable copy of an mbuf chain.
  606  */
  607 struct mbuf *
  608 m_dup(const struct mbuf *m, int how)
  609 {
  610         struct mbuf **p, *top = NULL;
  611         int remain, moff, nsize;
  612 
  613         MBUF_CHECKSLEEP(how);
  614         /* Sanity check */
  615         if (m == NULL)
  616                 return (NULL);
  617         M_ASSERTPKTHDR(m);
  618 
  619         /* While there's more data, get a new mbuf, tack it on, and fill it */
  620         remain = m->m_pkthdr.len;
  621         moff = 0;
  622         p = &top;
  623         while (remain > 0 || top == NULL) {     /* allow m->m_pkthdr.len == 0 */
  624                 struct mbuf *n;
  625 
  626                 /* Get the next new mbuf */
  627                 if (remain >= MINCLSIZE) {
  628                         n = m_getcl(how, m->m_type, 0);
  629                         nsize = MCLBYTES;
  630                 } else {
  631                         n = m_get(how, m->m_type);
  632                         nsize = MLEN;
  633                 }
  634                 if (n == NULL)
  635                         goto nospace;
  636 
  637                 if (top == NULL) {              /* First one, must be PKTHDR */
  638                         if (!m_dup_pkthdr(n, m, how)) {
  639                                 m_free(n);
  640                                 goto nospace;
  641                         }
  642                         if ((n->m_flags & M_EXT) == 0)
  643                                 nsize = MHLEN;
  644                         n->m_flags &= ~M_RDONLY;
  645                 }
  646                 n->m_len = 0;
  647 
  648                 /* Link it into the new chain */
  649                 *p = n;
  650                 p = &n->m_next;
  651 
  652                 /* Copy data from original mbuf(s) into new mbuf */
  653                 while (n->m_len < nsize && m != NULL) {
  654                         int chunk = min(nsize - n->m_len, m->m_len - moff);
  655 
  656                         bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
  657                         moff += chunk;
  658                         n->m_len += chunk;
  659                         remain -= chunk;
  660                         if (moff == m->m_len) {
  661                                 m = m->m_next;
  662                                 moff = 0;
  663                         }
  664                 }
  665 
  666                 /* Check correct total mbuf length */
  667                 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
  668                         ("%s: bogus m_pkthdr.len", __func__));
  669         }
  670         return (top);
  671 
  672 nospace:
  673         m_freem(top);
  674         return (NULL);
  675 }
  676 
  677 /*
  678  * Concatenate mbuf chain n to m.
  679  * Both chains must be of the same type (e.g. MT_DATA).
  680  * Any m_pkthdr is not updated.
  681  */
  682 void
  683 m_cat(struct mbuf *m, struct mbuf *n)
  684 {
  685         while (m->m_next)
  686                 m = m->m_next;
  687         while (n) {
  688                 if (!M_WRITABLE(m) ||
  689                     M_TRAILINGSPACE(m) < n->m_len) {
  690                         /* just join the two chains */
  691                         m->m_next = n;
  692                         return;
  693                 }
  694                 /* splat the data from one into the other */
  695                 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
  696                     (u_int)n->m_len);
  697                 m->m_len += n->m_len;
  698                 n = m_free(n);
  699         }
  700 }
  701 
  702 /*
  703  * Concatenate two pkthdr mbuf chains.
  704  */
  705 void
  706 m_catpkt(struct mbuf *m, struct mbuf *n)
  707 {
  708 
  709         M_ASSERTPKTHDR(m);
  710         M_ASSERTPKTHDR(n);
  711 
  712         m->m_pkthdr.len += n->m_pkthdr.len;
  713         m_demote(n, 1, 0);
  714 
  715         m_cat(m, n);
  716 }
  717 
  718 void
  719 m_adj(struct mbuf *mp, int req_len)
  720 {
  721         int len = req_len;
  722         struct mbuf *m;
  723         int count;
  724 
  725         if ((m = mp) == NULL)
  726                 return;
  727         if (len >= 0) {
  728                 /*
  729                  * Trim from head.
  730                  */
  731                 while (m != NULL && len > 0) {
  732                         if (m->m_len <= len) {
  733                                 len -= m->m_len;
  734                                 m->m_len = 0;
  735                                 m = m->m_next;
  736                         } else {
  737                                 m->m_len -= len;
  738                                 m->m_data += len;
  739                                 len = 0;
  740                         }
  741                 }
  742                 if (mp->m_flags & M_PKTHDR)
  743                         mp->m_pkthdr.len -= (req_len - len);
  744         } else {
  745                 /*
  746                  * Trim from tail.  Scan the mbuf chain,
  747                  * calculating its length and finding the last mbuf.
  748                  * If the adjustment only affects this mbuf, then just
  749                  * adjust and return.  Otherwise, rescan and truncate
  750                  * after the remaining size.
  751                  */
  752                 len = -len;
  753                 count = 0;
  754                 for (;;) {
  755                         count += m->m_len;
  756                         if (m->m_next == (struct mbuf *)0)
  757                                 break;
  758                         m = m->m_next;
  759                 }
  760                 if (m->m_len >= len) {
  761                         m->m_len -= len;
  762                         if (mp->m_flags & M_PKTHDR)
  763                                 mp->m_pkthdr.len -= len;
  764                         return;
  765                 }
  766                 count -= len;
  767                 if (count < 0)
  768                         count = 0;
  769                 /*
  770                  * Correct length for chain is "count".
  771                  * Find the mbuf with last data, adjust its length,
  772                  * and toss data from remaining mbufs on chain.
  773                  */
  774                 m = mp;
  775                 if (m->m_flags & M_PKTHDR)
  776                         m->m_pkthdr.len = count;
  777                 for (; m; m = m->m_next) {
  778                         if (m->m_len >= count) {
  779                                 m->m_len = count;
  780                                 if (m->m_next != NULL) {
  781                                         m_freem(m->m_next);
  782                                         m->m_next = NULL;
  783                                 }
  784                                 break;
  785                         }
  786                         count -= m->m_len;
  787                 }
  788         }
  789 }
  790 
  791 /*
  792  * Rearange an mbuf chain so that len bytes are contiguous
  793  * and in the data area of an mbuf (so that mtod will work
  794  * for a structure of size len).  Returns the resulting
  795  * mbuf chain on success, frees it and returns null on failure.
  796  * If there is room, it will add up to max_protohdr-len extra bytes to the
  797  * contiguous region in an attempt to avoid being called next time.
  798  */
  799 struct mbuf *
  800 m_pullup(struct mbuf *n, int len)
  801 {
  802         struct mbuf *m;
  803         int count;
  804         int space;
  805 
  806         /*
  807          * If first mbuf has no cluster, and has room for len bytes
  808          * without shifting current data, pullup into it,
  809          * otherwise allocate a new mbuf to prepend to the chain.
  810          */
  811         if ((n->m_flags & M_EXT) == 0 &&
  812             n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
  813                 if (n->m_len >= len)
  814                         return (n);
  815                 m = n;
  816                 n = n->m_next;
  817                 len -= m->m_len;
  818         } else {
  819                 if (len > MHLEN)
  820                         goto bad;
  821                 m = m_get(M_NOWAIT, n->m_type);
  822                 if (m == NULL)
  823                         goto bad;
  824                 if (n->m_flags & M_PKTHDR)
  825                         m_move_pkthdr(m, n);
  826         }
  827         space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
  828         do {
  829                 count = min(min(max(len, max_protohdr), space), n->m_len);
  830                 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
  831                   (u_int)count);
  832                 len -= count;
  833                 m->m_len += count;
  834                 n->m_len -= count;
  835                 space -= count;
  836                 if (n->m_len)
  837                         n->m_data += count;
  838                 else
  839                         n = m_free(n);
  840         } while (len > 0 && n);
  841         if (len > 0) {
  842                 (void) m_free(m);
  843                 goto bad;
  844         }
  845         m->m_next = n;
  846         return (m);
  847 bad:
  848         m_freem(n);
  849         return (NULL);
  850 }
  851 
  852 /*
  853  * Like m_pullup(), except a new mbuf is always allocated, and we allow
  854  * the amount of empty space before the data in the new mbuf to be specified
  855  * (in the event that the caller expects to prepend later).
  856  */
  857 struct mbuf *
  858 m_copyup(struct mbuf *n, int len, int dstoff)
  859 {
  860         struct mbuf *m;
  861         int count, space;
  862 
  863         if (len > (MHLEN - dstoff))
  864                 goto bad;
  865         m = m_get(M_NOWAIT, n->m_type);
  866         if (m == NULL)
  867                 goto bad;
  868         if (n->m_flags & M_PKTHDR)
  869                 m_move_pkthdr(m, n);
  870         m->m_data += dstoff;
  871         space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
  872         do {
  873                 count = min(min(max(len, max_protohdr), space), n->m_len);
  874                 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t),
  875                     (unsigned)count);
  876                 len -= count;
  877                 m->m_len += count;
  878                 n->m_len -= count;
  879                 space -= count;
  880                 if (n->m_len)
  881                         n->m_data += count;
  882                 else
  883                         n = m_free(n);
  884         } while (len > 0 && n);
  885         if (len > 0) {
  886                 (void) m_free(m);
  887                 goto bad;
  888         }
  889         m->m_next = n;
  890         return (m);
  891  bad:
  892         m_freem(n);
  893         return (NULL);
  894 }
  895 
  896 /*
  897  * Partition an mbuf chain in two pieces, returning the tail --
  898  * all but the first len0 bytes.  In case of failure, it returns NULL and
  899  * attempts to restore the chain to its original state.
  900  *
  901  * Note that the resulting mbufs might be read-only, because the new
  902  * mbuf can end up sharing an mbuf cluster with the original mbuf if
  903  * the "breaking point" happens to lie within a cluster mbuf. Use the
  904  * M_WRITABLE() macro to check for this case.
  905  */
  906 struct mbuf *
  907 m_split(struct mbuf *m0, int len0, int wait)
  908 {
  909         struct mbuf *m, *n;
  910         u_int len = len0, remain;
  911 
  912         MBUF_CHECKSLEEP(wait);
  913         for (m = m0; m && len > m->m_len; m = m->m_next)
  914                 len -= m->m_len;
  915         if (m == NULL)
  916                 return (NULL);
  917         remain = m->m_len - len;
  918         if (m0->m_flags & M_PKTHDR && remain == 0) {
  919                 n = m_gethdr(wait, m0->m_type);
  920                 if (n == NULL)
  921                         return (NULL);
  922                 n->m_next = m->m_next;
  923                 m->m_next = NULL;
  924                 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
  925                 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
  926                 m0->m_pkthdr.len = len0;
  927                 return (n);
  928         } else if (m0->m_flags & M_PKTHDR) {
  929                 n = m_gethdr(wait, m0->m_type);
  930                 if (n == NULL)
  931                         return (NULL);
  932                 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
  933                 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
  934                 m0->m_pkthdr.len = len0;
  935                 if (m->m_flags & M_EXT)
  936                         goto extpacket;
  937                 if (remain > MHLEN) {
  938                         /* m can't be the lead packet */
  939                         M_ALIGN(n, 0);
  940                         n->m_next = m_split(m, len, wait);
  941                         if (n->m_next == NULL) {
  942                                 (void) m_free(n);
  943                                 return (NULL);
  944                         } else {
  945                                 n->m_len = 0;
  946                                 return (n);
  947                         }
  948                 } else
  949                         M_ALIGN(n, remain);
  950         } else if (remain == 0) {
  951                 n = m->m_next;
  952                 m->m_next = NULL;
  953                 return (n);
  954         } else {
  955                 n = m_get(wait, m->m_type);
  956                 if (n == NULL)
  957                         return (NULL);
  958                 M_ALIGN(n, remain);
  959         }
  960 extpacket:
  961         if (m->m_flags & M_EXT) {
  962                 n->m_data = m->m_data + len;
  963                 mb_dupcl(n, m);
  964         } else {
  965                 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
  966         }
  967         n->m_len = remain;
  968         m->m_len = len;
  969         n->m_next = m->m_next;
  970         m->m_next = NULL;
  971         return (n);
  972 }
  973 /*
  974  * Routine to copy from device local memory into mbufs.
  975  * Note that `off' argument is offset into first mbuf of target chain from
  976  * which to begin copying the data to.
  977  */
  978 struct mbuf *
  979 m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
  980     void (*copy)(char *from, caddr_t to, u_int len))
  981 {
  982         struct mbuf *m;
  983         struct mbuf *top = NULL, **mp = &top;
  984         int len;
  985 
  986         if (off < 0 || off > MHLEN)
  987                 return (NULL);
  988 
  989         while (totlen > 0) {
  990                 if (top == NULL) {      /* First one, must be PKTHDR */
  991                         if (totlen + off >= MINCLSIZE) {
  992                                 m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
  993                                 len = MCLBYTES;
  994                         } else {
  995                                 m = m_gethdr(M_NOWAIT, MT_DATA);
  996                                 len = MHLEN;
  997 
  998                                 /* Place initial small packet/header at end of mbuf */
  999                                 if (m && totlen + off + max_linkhdr <= MHLEN) {
 1000                                         m->m_data += max_linkhdr;
 1001                                         len -= max_linkhdr;
 1002                                 }
 1003                         }
 1004                         if (m == NULL)
 1005                                 return NULL;
 1006                         m->m_pkthdr.rcvif = ifp;
 1007                         m->m_pkthdr.len = totlen;
 1008                 } else {
 1009                         if (totlen + off >= MINCLSIZE) {
 1010                                 m = m_getcl(M_NOWAIT, MT_DATA, 0);
 1011                                 len = MCLBYTES;
 1012                         } else {
 1013                                 m = m_get(M_NOWAIT, MT_DATA);
 1014                                 len = MLEN;
 1015                         }
 1016                         if (m == NULL) {
 1017                                 m_freem(top);
 1018                                 return NULL;
 1019                         }
 1020                 }
 1021                 if (off) {
 1022                         m->m_data += off;
 1023                         len -= off;
 1024                         off = 0;
 1025                 }
 1026                 m->m_len = len = min(totlen, len);
 1027                 if (copy)
 1028                         copy(buf, mtod(m, caddr_t), (u_int)len);
 1029                 else
 1030                         bcopy(buf, mtod(m, caddr_t), (u_int)len);
 1031                 buf += len;
 1032                 *mp = m;
 1033                 mp = &m->m_next;
 1034                 totlen -= len;
 1035         }
 1036         return (top);
 1037 }
 1038 
 1039 /*
 1040  * Copy data from a buffer back into the indicated mbuf chain,
 1041  * starting "off" bytes from the beginning, extending the mbuf
 1042  * chain if necessary.
 1043  */
 1044 void
 1045 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp)
 1046 {
 1047         int mlen;
 1048         struct mbuf *m = m0, *n;
 1049         int totlen = 0;
 1050 
 1051         if (m0 == NULL)
 1052                 return;
 1053         while (off > (mlen = m->m_len)) {
 1054                 off -= mlen;
 1055                 totlen += mlen;
 1056                 if (m->m_next == NULL) {
 1057                         n = m_get(M_NOWAIT, m->m_type);
 1058                         if (n == NULL)
 1059                                 goto out;
 1060                         bzero(mtod(n, caddr_t), MLEN);
 1061                         n->m_len = min(MLEN, len + off);
 1062                         m->m_next = n;
 1063                 }
 1064                 m = m->m_next;
 1065         }
 1066         while (len > 0) {
 1067                 if (m->m_next == NULL && (len > m->m_len - off)) {
 1068                         m->m_len += min(len - (m->m_len - off),
 1069                             M_TRAILINGSPACE(m));
 1070                 }
 1071                 mlen = min (m->m_len - off, len);
 1072                 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen);
 1073                 cp += mlen;
 1074                 len -= mlen;
 1075                 mlen += off;
 1076                 off = 0;
 1077                 totlen += mlen;
 1078                 if (len == 0)
 1079                         break;
 1080                 if (m->m_next == NULL) {
 1081                         n = m_get(M_NOWAIT, m->m_type);
 1082                         if (n == NULL)
 1083                                 break;
 1084                         n->m_len = min(MLEN, len);
 1085                         m->m_next = n;
 1086                 }
 1087                 m = m->m_next;
 1088         }
 1089 out:    if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
 1090                 m->m_pkthdr.len = totlen;
 1091 }
 1092 
 1093 /*
 1094  * Append the specified data to the indicated mbuf chain,
 1095  * Extend the mbuf chain if the new data does not fit in
 1096  * existing space.
 1097  *
 1098  * Return 1 if able to complete the job; otherwise 0.
 1099  */
 1100 int
 1101 m_append(struct mbuf *m0, int len, c_caddr_t cp)
 1102 {
 1103         struct mbuf *m, *n;
 1104         int remainder, space;
 1105 
 1106         for (m = m0; m->m_next != NULL; m = m->m_next)
 1107                 ;
 1108         remainder = len;
 1109         space = M_TRAILINGSPACE(m);
 1110         if (space > 0) {
 1111                 /*
 1112                  * Copy into available space.
 1113                  */
 1114                 if (space > remainder)
 1115                         space = remainder;
 1116                 bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
 1117                 m->m_len += space;
 1118                 cp += space, remainder -= space;
 1119         }
 1120         while (remainder > 0) {
 1121                 /*
 1122                  * Allocate a new mbuf; could check space
 1123                  * and allocate a cluster instead.
 1124                  */
 1125                 n = m_get(M_NOWAIT, m->m_type);
 1126                 if (n == NULL)
 1127                         break;
 1128                 n->m_len = min(MLEN, remainder);
 1129                 bcopy(cp, mtod(n, caddr_t), n->m_len);
 1130                 cp += n->m_len, remainder -= n->m_len;
 1131                 m->m_next = n;
 1132                 m = n;
 1133         }
 1134         if (m0->m_flags & M_PKTHDR)
 1135                 m0->m_pkthdr.len += len - remainder;
 1136         return (remainder == 0);
 1137 }
 1138 
 1139 /*
 1140  * Apply function f to the data in an mbuf chain starting "off" bytes from
 1141  * the beginning, continuing for "len" bytes.
 1142  */
 1143 int
 1144 m_apply(struct mbuf *m, int off, int len,
 1145     int (*f)(void *, void *, u_int), void *arg)
 1146 {
 1147         u_int count;
 1148         int rval;
 1149 
 1150         KASSERT(off >= 0, ("m_apply, negative off %d", off));
 1151         KASSERT(len >= 0, ("m_apply, negative len %d", len));
 1152         while (off > 0) {
 1153                 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
 1154                 if (off < m->m_len)
 1155                         break;
 1156                 off -= m->m_len;
 1157                 m = m->m_next;
 1158         }
 1159         while (len > 0) {
 1160                 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
 1161                 count = min(m->m_len - off, len);
 1162                 rval = (*f)(arg, mtod(m, caddr_t) + off, count);
 1163                 if (rval)
 1164                         return (rval);
 1165                 len -= count;
 1166                 off = 0;
 1167                 m = m->m_next;
 1168         }
 1169         return (0);
 1170 }
 1171 
 1172 /*
 1173  * Return a pointer to mbuf/offset of location in mbuf chain.
 1174  */
 1175 struct mbuf *
 1176 m_getptr(struct mbuf *m, int loc, int *off)
 1177 {
 1178 
 1179         while (loc >= 0) {
 1180                 /* Normal end of search. */
 1181                 if (m->m_len > loc) {
 1182                         *off = loc;
 1183                         return (m);
 1184                 } else {
 1185                         loc -= m->m_len;
 1186                         if (m->m_next == NULL) {
 1187                                 if (loc == 0) {
 1188                                         /* Point at the end of valid data. */
 1189                                         *off = m->m_len;
 1190                                         return (m);
 1191                                 }
 1192                                 return (NULL);
 1193                         }
 1194                         m = m->m_next;
 1195                 }
 1196         }
 1197         return (NULL);
 1198 }
 1199 
 1200 void
 1201 m_print(const struct mbuf *m, int maxlen)
 1202 {
 1203         int len;
 1204         int pdata;
 1205         const struct mbuf *m2;
 1206 
 1207         if (m == NULL) {
 1208                 printf("mbuf: %p\n", m);
 1209                 return;
 1210         }
 1211 
 1212         if (m->m_flags & M_PKTHDR)
 1213                 len = m->m_pkthdr.len;
 1214         else
 1215                 len = -1;
 1216         m2 = m;
 1217         while (m2 != NULL && (len == -1 || len)) {
 1218                 pdata = m2->m_len;
 1219                 if (maxlen != -1 && pdata > maxlen)
 1220                         pdata = maxlen;
 1221                 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len,
 1222                     m2->m_next, m2->m_flags, "\2\20freelist\17skipfw"
 1223                     "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly"
 1224                     "\3eor\2pkthdr\1ext", pdata ? "" : "\n");
 1225                 if (pdata)
 1226                         printf(", %*D\n", pdata, (u_char *)m2->m_data, "-");
 1227                 if (len != -1)
 1228                         len -= m2->m_len;
 1229                 m2 = m2->m_next;
 1230         }
 1231         if (len > 0)
 1232                 printf("%d bytes unaccounted for.\n", len);
 1233         return;
 1234 }
 1235 
 1236 u_int
 1237 m_fixhdr(struct mbuf *m0)
 1238 {
 1239         u_int len;
 1240 
 1241         len = m_length(m0, NULL);
 1242         m0->m_pkthdr.len = len;
 1243         return (len);
 1244 }
 1245 
 1246 u_int
 1247 m_length(struct mbuf *m0, struct mbuf **last)
 1248 {
 1249         struct mbuf *m;
 1250         u_int len;
 1251 
 1252         len = 0;
 1253         for (m = m0; m != NULL; m = m->m_next) {
 1254                 len += m->m_len;
 1255                 if (m->m_next == NULL)
 1256                         break;
 1257         }
 1258         if (last != NULL)
 1259                 *last = m;
 1260         return (len);
 1261 }
 1262 
 1263 /*
 1264  * Defragment a mbuf chain, returning the shortest possible
 1265  * chain of mbufs and clusters.  If allocation fails and
 1266  * this cannot be completed, NULL will be returned, but
 1267  * the passed in chain will be unchanged.  Upon success,
 1268  * the original chain will be freed, and the new chain
 1269  * will be returned.
 1270  *
 1271  * If a non-packet header is passed in, the original
 1272  * mbuf (chain?) will be returned unharmed.
 1273  */
 1274 struct mbuf *
 1275 m_defrag(struct mbuf *m0, int how)
 1276 {
 1277         struct mbuf *m_new = NULL, *m_final = NULL;
 1278         int progress = 0, length;
 1279 
 1280         MBUF_CHECKSLEEP(how);
 1281         if (!(m0->m_flags & M_PKTHDR))
 1282                 return (m0);
 1283 
 1284         m_fixhdr(m0); /* Needed sanity check */
 1285 
 1286 #ifdef MBUF_STRESS_TEST
 1287         if (m_defragrandomfailures) {
 1288                 int temp = arc4random() & 0xff;
 1289                 if (temp == 0xba)
 1290                         goto nospace;
 1291         }
 1292 #endif
 1293 
 1294         if (m0->m_pkthdr.len > MHLEN)
 1295                 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
 1296         else
 1297                 m_final = m_gethdr(how, MT_DATA);
 1298 
 1299         if (m_final == NULL)
 1300                 goto nospace;
 1301 
 1302         if (m_dup_pkthdr(m_final, m0, how) == 0)
 1303                 goto nospace;
 1304 
 1305         m_new = m_final;
 1306 
 1307         while (progress < m0->m_pkthdr.len) {
 1308                 length = m0->m_pkthdr.len - progress;
 1309                 if (length > MCLBYTES)
 1310                         length = MCLBYTES;
 1311 
 1312                 if (m_new == NULL) {
 1313                         if (length > MLEN)
 1314                                 m_new = m_getcl(how, MT_DATA, 0);
 1315                         else
 1316                                 m_new = m_get(how, MT_DATA);
 1317                         if (m_new == NULL)
 1318                                 goto nospace;
 1319                 }
 1320 
 1321                 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
 1322                 progress += length;
 1323                 m_new->m_len = length;
 1324                 if (m_new != m_final)
 1325                         m_cat(m_final, m_new);
 1326                 m_new = NULL;
 1327         }
 1328 #ifdef MBUF_STRESS_TEST
 1329         if (m0->m_next == NULL)
 1330                 m_defraguseless++;
 1331 #endif
 1332         m_freem(m0);
 1333         m0 = m_final;
 1334 #ifdef MBUF_STRESS_TEST
 1335         m_defragpackets++;
 1336         m_defragbytes += m0->m_pkthdr.len;
 1337 #endif
 1338         return (m0);
 1339 nospace:
 1340 #ifdef MBUF_STRESS_TEST
 1341         m_defragfailure++;
 1342 #endif
 1343         if (m_final)
 1344                 m_freem(m_final);
 1345         return (NULL);
 1346 }
 1347 
 1348 /*
 1349  * Defragment an mbuf chain, returning at most maxfrags separate
 1350  * mbufs+clusters.  If this is not possible NULL is returned and
 1351  * the original mbuf chain is left in its present (potentially
 1352  * modified) state.  We use two techniques: collapsing consecutive
 1353  * mbufs and replacing consecutive mbufs by a cluster.
 1354  *
 1355  * NB: this should really be named m_defrag but that name is taken
 1356  */
 1357 struct mbuf *
 1358 m_collapse(struct mbuf *m0, int how, int maxfrags)
 1359 {
 1360         struct mbuf *m, *n, *n2, **prev;
 1361         u_int curfrags;
 1362 
 1363         /*
 1364          * Calculate the current number of frags.
 1365          */
 1366         curfrags = 0;
 1367         for (m = m0; m != NULL; m = m->m_next)
 1368                 curfrags++;
 1369         /*
 1370          * First, try to collapse mbufs.  Note that we always collapse
 1371          * towards the front so we don't need to deal with moving the
 1372          * pkthdr.  This may be suboptimal if the first mbuf has much
 1373          * less data than the following.
 1374          */
 1375         m = m0;
 1376 again:
 1377         for (;;) {
 1378                 n = m->m_next;
 1379                 if (n == NULL)
 1380                         break;
 1381                 if (M_WRITABLE(m) &&
 1382                     n->m_len < M_TRAILINGSPACE(m)) {
 1383                         bcopy(mtod(n, void *), mtod(m, char *) + m->m_len,
 1384                                 n->m_len);
 1385                         m->m_len += n->m_len;
 1386                         m->m_next = n->m_next;
 1387                         m_free(n);
 1388                         if (--curfrags <= maxfrags)
 1389                                 return m0;
 1390                 } else
 1391                         m = n;
 1392         }
 1393         KASSERT(maxfrags > 1,
 1394                 ("maxfrags %u, but normal collapse failed", maxfrags));
 1395         /*
 1396          * Collapse consecutive mbufs to a cluster.
 1397          */
 1398         prev = &m0->m_next;             /* NB: not the first mbuf */
 1399         while ((n = *prev) != NULL) {
 1400                 if ((n2 = n->m_next) != NULL &&
 1401                     n->m_len + n2->m_len < MCLBYTES) {
 1402                         m = m_getcl(how, MT_DATA, 0);
 1403                         if (m == NULL)
 1404                                 goto bad;
 1405                         bcopy(mtod(n, void *), mtod(m, void *), n->m_len);
 1406                         bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len,
 1407                                 n2->m_len);
 1408                         m->m_len = n->m_len + n2->m_len;
 1409                         m->m_next = n2->m_next;
 1410                         *prev = m;
 1411                         m_free(n);
 1412                         m_free(n2);
 1413                         if (--curfrags <= maxfrags)     /* +1 cl -2 mbufs */
 1414                                 return m0;
 1415                         /*
 1416                          * Still not there, try the normal collapse
 1417                          * again before we allocate another cluster.
 1418                          */
 1419                         goto again;
 1420                 }
 1421                 prev = &n->m_next;
 1422         }
 1423         /*
 1424          * No place where we can collapse to a cluster; punt.
 1425          * This can occur if, for example, you request 2 frags
 1426          * but the packet requires that both be clusters (we
 1427          * never reallocate the first mbuf to avoid moving the
 1428          * packet header).
 1429          */
 1430 bad:
 1431         return NULL;
 1432 }
 1433 
 1434 #ifdef MBUF_STRESS_TEST
 1435 
 1436 /*
 1437  * Fragment an mbuf chain.  There's no reason you'd ever want to do
 1438  * this in normal usage, but it's great for stress testing various
 1439  * mbuf consumers.
 1440  *
 1441  * If fragmentation is not possible, the original chain will be
 1442  * returned.
 1443  *
 1444  * Possible length values:
 1445  * 0     no fragmentation will occur
 1446  * > 0  each fragment will be of the specified length
 1447  * -1   each fragment will be the same random value in length
 1448  * -2   each fragment's length will be entirely random
 1449  * (Random values range from 1 to 256)
 1450  */
 1451 struct mbuf *
 1452 m_fragment(struct mbuf *m0, int how, int length)
 1453 {
 1454         struct mbuf *m_first, *m_last;
 1455         int divisor = 255, progress = 0, fraglen;
 1456 
 1457         if (!(m0->m_flags & M_PKTHDR))
 1458                 return (m0);
 1459 
 1460         if (length == 0 || length < -2)
 1461                 return (m0);
 1462         if (length > MCLBYTES)
 1463                 length = MCLBYTES;
 1464         if (length < 0 && divisor > MCLBYTES)
 1465                 divisor = MCLBYTES;
 1466         if (length == -1)
 1467                 length = 1 + (arc4random() % divisor);
 1468         if (length > 0)
 1469                 fraglen = length;
 1470 
 1471         m_fixhdr(m0); /* Needed sanity check */
 1472 
 1473         m_first = m_getcl(how, MT_DATA, M_PKTHDR);
 1474         if (m_first == NULL)
 1475                 goto nospace;
 1476 
 1477         if (m_dup_pkthdr(m_first, m0, how) == 0)
 1478                 goto nospace;
 1479 
 1480         m_last = m_first;
 1481 
 1482         while (progress < m0->m_pkthdr.len) {
 1483                 if (length == -2)
 1484                         fraglen = 1 + (arc4random() % divisor);
 1485                 if (fraglen > m0->m_pkthdr.len - progress)
 1486                         fraglen = m0->m_pkthdr.len - progress;
 1487 
 1488                 if (progress != 0) {
 1489                         struct mbuf *m_new = m_getcl(how, MT_DATA, 0);
 1490                         if (m_new == NULL)
 1491                                 goto nospace;
 1492 
 1493                         m_last->m_next = m_new;
 1494                         m_last = m_new;
 1495                 }
 1496 
 1497                 m_copydata(m0, progress, fraglen, mtod(m_last, caddr_t));
 1498                 progress += fraglen;
 1499                 m_last->m_len = fraglen;
 1500         }
 1501         m_freem(m0);
 1502         m0 = m_first;
 1503         return (m0);
 1504 nospace:
 1505         if (m_first)
 1506                 m_freem(m_first);
 1507         /* Return the original chain on failure */
 1508         return (m0);
 1509 }
 1510 
 1511 #endif
 1512 
 1513 /*
 1514  * Copy the contents of uio into a properly sized mbuf chain.
 1515  */
 1516 struct mbuf *
 1517 m_uiotombuf(struct uio *uio, int how, int len, int align, int flags)
 1518 {
 1519         struct mbuf *m, *mb;
 1520         int error, length;
 1521         ssize_t total;
 1522         int progress = 0;
 1523 
 1524         /*
 1525          * len can be zero or an arbitrary large value bound by
 1526          * the total data supplied by the uio.
 1527          */
 1528         if (len > 0)
 1529                 total = (uio->uio_resid < len) ? uio->uio_resid : len;
 1530         else
 1531                 total = uio->uio_resid;
 1532 
 1533         /*
 1534          * The smallest unit returned by m_getm2() is a single mbuf
 1535          * with pkthdr.  We can't align past it.
 1536          */
 1537         if (align >= MHLEN)
 1538                 return (NULL);
 1539 
 1540         /*
 1541          * Give us the full allocation or nothing.
 1542          * If len is zero return the smallest empty mbuf.
 1543          */
 1544         m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags);
 1545         if (m == NULL)
 1546                 return (NULL);
 1547         m->m_data += align;
 1548 
 1549         /* Fill all mbufs with uio data and update header information. */
 1550         for (mb = m; mb != NULL; mb = mb->m_next) {
 1551                 length = min(M_TRAILINGSPACE(mb), total - progress);
 1552 
 1553                 error = uiomove(mtod(mb, void *), length, uio);
 1554                 if (error) {
 1555                         m_freem(m);
 1556                         return (NULL);
 1557                 }
 1558 
 1559                 mb->m_len = length;
 1560                 progress += length;
 1561                 if (flags & M_PKTHDR)
 1562                         m->m_pkthdr.len += length;
 1563         }
 1564         KASSERT(progress == total, ("%s: progress != total", __func__));
 1565 
 1566         return (m);
 1567 }
 1568 
 1569 /*
 1570  * Copy an mbuf chain into a uio limited by len if set.
 1571  */
 1572 int
 1573 m_mbuftouio(struct uio *uio, const struct mbuf *m, int len)
 1574 {
 1575         int error, length, total;
 1576         int progress = 0;
 1577 
 1578         if (len > 0)
 1579                 total = min(uio->uio_resid, len);
 1580         else
 1581                 total = uio->uio_resid;
 1582 
 1583         /* Fill the uio with data from the mbufs. */
 1584         for (; m != NULL; m = m->m_next) {
 1585                 length = min(m->m_len, total - progress);
 1586 
 1587                 error = uiomove(mtod(m, void *), length, uio);
 1588                 if (error)
 1589                         return (error);
 1590 
 1591                 progress += length;
 1592         }
 1593 
 1594         return (0);
 1595 }
 1596 
 1597 /*
 1598  * Create a writable copy of the mbuf chain.  While doing this
 1599  * we compact the chain with a goal of producing a chain with
 1600  * at most two mbufs.  The second mbuf in this chain is likely
 1601  * to be a cluster.  The primary purpose of this work is to create
 1602  * a writable packet for encryption, compression, etc.  The
 1603  * secondary goal is to linearize the data so the data can be
 1604  * passed to crypto hardware in the most efficient manner possible.
 1605  */
 1606 struct mbuf *
 1607 m_unshare(struct mbuf *m0, int how)
 1608 {
 1609         struct mbuf *m, *mprev;
 1610         struct mbuf *n, *mfirst, *mlast;
 1611         int len, off;
 1612 
 1613         mprev = NULL;
 1614         for (m = m0; m != NULL; m = mprev->m_next) {
 1615                 /*
 1616                  * Regular mbufs are ignored unless there's a cluster
 1617                  * in front of it that we can use to coalesce.  We do
 1618                  * the latter mainly so later clusters can be coalesced
 1619                  * also w/o having to handle them specially (i.e. convert
 1620                  * mbuf+cluster -> cluster).  This optimization is heavily
 1621                  * influenced by the assumption that we're running over
 1622                  * Ethernet where MCLBYTES is large enough that the max
 1623                  * packet size will permit lots of coalescing into a
 1624                  * single cluster.  This in turn permits efficient
 1625                  * crypto operations, especially when using hardware.
 1626                  */
 1627                 if ((m->m_flags & M_EXT) == 0) {
 1628                         if (mprev && (mprev->m_flags & M_EXT) &&
 1629                             m->m_len <= M_TRAILINGSPACE(mprev)) {
 1630                                 /* XXX: this ignores mbuf types */
 1631                                 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
 1632                                     mtod(m, caddr_t), m->m_len);
 1633                                 mprev->m_len += m->m_len;
 1634                                 mprev->m_next = m->m_next;      /* unlink from chain */
 1635                                 m_free(m);                      /* reclaim mbuf */
 1636                         } else {
 1637                                 mprev = m;
 1638                         }
 1639                         continue;
 1640                 }
 1641                 /*
 1642                  * Writable mbufs are left alone (for now).
 1643                  */
 1644                 if (M_WRITABLE(m)) {
 1645                         mprev = m;
 1646                         continue;
 1647                 }
 1648 
 1649                 /*
 1650                  * Not writable, replace with a copy or coalesce with
 1651                  * the previous mbuf if possible (since we have to copy
 1652                  * it anyway, we try to reduce the number of mbufs and
 1653                  * clusters so that future work is easier).
 1654                  */
 1655                 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags));
 1656                 /* NB: we only coalesce into a cluster or larger */
 1657                 if (mprev != NULL && (mprev->m_flags & M_EXT) &&
 1658                     m->m_len <= M_TRAILINGSPACE(mprev)) {
 1659                         /* XXX: this ignores mbuf types */
 1660                         memcpy(mtod(mprev, caddr_t) + mprev->m_len,
 1661                             mtod(m, caddr_t), m->m_len);
 1662                         mprev->m_len += m->m_len;
 1663                         mprev->m_next = m->m_next;      /* unlink from chain */
 1664                         m_free(m);                      /* reclaim mbuf */
 1665                         continue;
 1666                 }
 1667 
 1668                 /*
 1669                  * Allocate new space to hold the copy and copy the data.
 1670                  * We deal with jumbo mbufs (i.e. m_len > MCLBYTES) by
 1671                  * splitting them into clusters.  We could just malloc a
 1672                  * buffer and make it external but too many device drivers
 1673                  * don't know how to break up the non-contiguous memory when
 1674                  * doing DMA.
 1675                  */
 1676                 n = m_getcl(how, m->m_type, m->m_flags & M_COPYFLAGS);
 1677                 if (n == NULL) {
 1678                         m_freem(m0);
 1679                         return (NULL);
 1680                 }
 1681                 if (m->m_flags & M_PKTHDR) {
 1682                         KASSERT(mprev == NULL, ("%s: m0 %p, m %p has M_PKTHDR",
 1683                             __func__, m0, m));
 1684                         m_move_pkthdr(n, m);
 1685                 }
 1686                 len = m->m_len;
 1687                 off = 0;
 1688                 mfirst = n;
 1689                 mlast = NULL;
 1690                 for (;;) {
 1691                         int cc = min(len, MCLBYTES);
 1692                         memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc);
 1693                         n->m_len = cc;
 1694                         if (mlast != NULL)
 1695                                 mlast->m_next = n;
 1696                         mlast = n;
 1697 #if 0
 1698                         newipsecstat.ips_clcopied++;
 1699 #endif
 1700 
 1701                         len -= cc;
 1702                         if (len <= 0)
 1703                                 break;
 1704                         off += cc;
 1705 
 1706                         n = m_getcl(how, m->m_type, m->m_flags & M_COPYFLAGS);
 1707                         if (n == NULL) {
 1708                                 m_freem(mfirst);
 1709                                 m_freem(m0);
 1710                                 return (NULL);
 1711                         }
 1712                 }
 1713                 n->m_next = m->m_next;
 1714                 if (mprev == NULL)
 1715                         m0 = mfirst;            /* new head of chain */
 1716                 else
 1717                         mprev->m_next = mfirst; /* replace old mbuf */
 1718                 m_free(m);                      /* release old mbuf */
 1719                 mprev = mfirst;
 1720         }
 1721         return (m0);
 1722 }
 1723 
 1724 #ifdef MBUF_PROFILING
 1725 
 1726 #define MP_BUCKETS 32 /* don't just change this as things may overflow.*/
 1727 struct mbufprofile {
 1728         uintmax_t wasted[MP_BUCKETS];
 1729         uintmax_t used[MP_BUCKETS];
 1730         uintmax_t segments[MP_BUCKETS];
 1731 } mbprof;
 1732 
 1733 #define MP_MAXDIGITS 21 /* strlen("16,000,000,000,000,000,000") == 21 */
 1734 #define MP_NUMLINES 6
 1735 #define MP_NUMSPERLINE 16
 1736 #define MP_EXTRABYTES 64        /* > strlen("used:\nwasted:\nsegments:\n") */
 1737 /* work out max space needed and add a bit of spare space too */
 1738 #define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE)
 1739 #define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES)
 1740 
 1741 char mbprofbuf[MP_BUFSIZE];
 1742 
 1743 void
 1744 m_profile(struct mbuf *m)
 1745 {
 1746         int segments = 0;
 1747         int used = 0;
 1748         int wasted = 0;
 1749 
 1750         while (m) {
 1751                 segments++;
 1752                 used += m->m_len;
 1753                 if (m->m_flags & M_EXT) {
 1754                         wasted += MHLEN - sizeof(m->m_ext) +
 1755                             m->m_ext.ext_size - m->m_len;
 1756                 } else {
 1757                         if (m->m_flags & M_PKTHDR)
 1758                                 wasted += MHLEN - m->m_len;
 1759                         else
 1760                                 wasted += MLEN - m->m_len;
 1761                 }
 1762                 m = m->m_next;
 1763         }
 1764         /* be paranoid.. it helps */
 1765         if (segments > MP_BUCKETS - 1)
 1766                 segments = MP_BUCKETS - 1;
 1767         if (used > 100000)
 1768                 used = 100000;
 1769         if (wasted > 100000)
 1770                 wasted = 100000;
 1771         /* store in the appropriate bucket */
 1772         /* don't bother locking. if it's slightly off, so what? */
 1773         mbprof.segments[segments]++;
 1774         mbprof.used[fls(used)]++;
 1775         mbprof.wasted[fls(wasted)]++;
 1776 }
 1777 
 1778 static void
 1779 mbprof_textify(void)
 1780 {
 1781         int offset;
 1782         char *c;
 1783         uint64_t *p;
 1784 
 1785         p = &mbprof.wasted[0];
 1786         c = mbprofbuf;
 1787         offset = snprintf(c, MP_MAXLINE + 10,
 1788             "wasted:\n"
 1789             "%ju %ju %ju %ju %ju %ju %ju %ju "
 1790             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
 1791             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
 1792             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
 1793 #ifdef BIG_ARRAY
 1794         p = &mbprof.wasted[16];
 1795         c += offset;
 1796         offset = snprintf(c, MP_MAXLINE,
 1797             "%ju %ju %ju %ju %ju %ju %ju %ju "
 1798             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
 1799             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
 1800             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
 1801 #endif
 1802         p = &mbprof.used[0];
 1803         c += offset;
 1804         offset = snprintf(c, MP_MAXLINE + 10,
 1805             "used:\n"
 1806             "%ju %ju %ju %ju %ju %ju %ju %ju "
 1807             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
 1808             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
 1809             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
 1810 #ifdef BIG_ARRAY
 1811         p = &mbprof.used[16];
 1812         c += offset;
 1813         offset = snprintf(c, MP_MAXLINE,
 1814             "%ju %ju %ju %ju %ju %ju %ju %ju "
 1815             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
 1816             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
 1817             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
 1818 #endif
 1819         p = &mbprof.segments[0];
 1820         c += offset;
 1821         offset = snprintf(c, MP_MAXLINE + 10,
 1822             "segments:\n"
 1823             "%ju %ju %ju %ju %ju %ju %ju %ju "
 1824             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
 1825             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
 1826             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
 1827 #ifdef BIG_ARRAY
 1828         p = &mbprof.segments[16];
 1829         c += offset;
 1830         offset = snprintf(c, MP_MAXLINE,
 1831             "%ju %ju %ju %ju %ju %ju %ju %ju "
 1832             "%ju %ju %ju %ju %ju %ju %ju %jju",
 1833             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
 1834             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
 1835 #endif
 1836 }
 1837 
 1838 static int
 1839 mbprof_handler(SYSCTL_HANDLER_ARGS)
 1840 {
 1841         int error;
 1842 
 1843         mbprof_textify();
 1844         error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1);
 1845         return (error);
 1846 }
 1847 
 1848 static int
 1849 mbprof_clr_handler(SYSCTL_HANDLER_ARGS)
 1850 {
 1851         int clear, error;
 1852 
 1853         clear = 0;
 1854         error = sysctl_handle_int(oidp, &clear, 0, req);
 1855         if (error || !req->newptr)
 1856                 return (error);
 1857 
 1858         if (clear) {
 1859                 bzero(&mbprof, sizeof(mbprof));
 1860         }
 1861 
 1862         return (error);
 1863 }
 1864 
 1865 
 1866 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, CTLTYPE_STRING|CTLFLAG_RD,
 1867             NULL, 0, mbprof_handler, "A", "mbuf profiling statistics");
 1868 
 1869 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, CTLTYPE_INT|CTLFLAG_RW,
 1870             NULL, 0, mbprof_clr_handler, "I", "clear mbuf profiling statistics");
 1871 #endif
 1872 

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