sys/kern/uipc_mbuf.c

   1 /*-
   2  * Copyright (c) 1982, 1986, 1988, 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)uipc_mbuf.c 8.2 (Berkeley) 1/4/94
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include "opt_mac.h"
  36 #include "opt_param.h"
  37 #include "opt_mbuf_stress_test.h"
  38 #include "opt_mbuf_profiling.h"
  39
  40 #include <sys/param.h>
  41 #include <sys/systm.h>
  42 #include <sys/kernel.h>
  43 #include <sys/limits.h>
  44 #include <sys/lock.h>
  45 #include <sys/malloc.h>
  46 #include <sys/mbuf.h>
  47 #include <sys/sysctl.h>
  48 #include <sys/domain.h>
  49 #include <sys/protosw.h>
  50 #include <sys/uio.h>
  51
  52 #include <security/mac/mac_framework.h>
  53
  54 int     max_linkhdr;
  55 int     max_protohdr;
  56 int     max_hdr;
  57 int     max_datalen;
  58 #ifdef MBUF_STRESS_TEST
  59 int     m_defragpackets;
  60 int     m_defragbytes;
  61 int     m_defraguseless;
  62 int     m_defragfailure;
  63 int     m_defragrandomfailures;
  64 #endif
  65
  66 /*
  67  * sysctl(8) exported objects
  68  */
  69 SYSCTL_INT(_kern_ipc, KIPC_MAX_LINKHDR, max_linkhdr, CTLFLAG_RD,
  70            &max_linkhdr, 0, "Size of largest link layer header");
  71 SYSCTL_INT(_kern_ipc, KIPC_MAX_PROTOHDR, max_protohdr, CTLFLAG_RD,
  72            &max_protohdr, 0, "Size of largest protocol layer header");
  73 SYSCTL_INT(_kern_ipc, KIPC_MAX_HDR, max_hdr, CTLFLAG_RD,
  74            &max_hdr, 0, "Size of largest link plus protocol header");
  75 SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RD,
  76            &max_datalen, 0, "Minimum space left in mbuf after max_hdr");
  77 #ifdef MBUF_STRESS_TEST
  78 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragpackets, CTLFLAG_RD,
  79            &m_defragpackets, 0, "");
  80 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragbytes, CTLFLAG_RD,
  81            &m_defragbytes, 0, "");
  82 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defraguseless, CTLFLAG_RD,
  83            &m_defraguseless, 0, "");
  84 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragfailure, CTLFLAG_RD,
  85            &m_defragfailure, 0, "");
  86 SYSCTL_INT(_kern_ipc, OID_AUTO, m_defragrandomfailures, CTLFLAG_RW,
  87            &m_defragrandomfailures, 0, "");
  88 #endif
  89
  90 /*
  91  * Allocate a given length worth of mbufs and/or clusters (whatever fits
  92  * best) and return a pointer to the top of the allocated chain.  If an
  93  * existing mbuf chain is provided, then we will append the new chain
  94  * to the existing one but still return the top of the newly allocated
  95  * chain.
  96  */
  97 struct mbuf *
  98 m_getm2(struct mbuf *m, int len, int how, short type, int flags)
  99 {
 100         struct mbuf *mb, *nm = NULL, *mtail = NULL;
 101
 102         KASSERT(len >= 0, ("%s: len is < 0", __func__));
 103
 104         /* Validate flags. */
 105         flags &= (M_PKTHDR | M_EOR);
 106
 107         /* Packet header mbuf must be first in chain. */
 108         if ((flags & M_PKTHDR) && m != NULL)
 109                 flags &= ~M_PKTHDR;
 110
 111         /* Loop and append maximum sized mbufs to the chain tail. */
 112         while (len > 0) {
 113                 if (len > MCLBYTES)
 114                         mb = m_getjcl(how, type, (flags & M_PKTHDR),
 115                             MJUMPAGESIZE);
 116                 else if (len >= MINCLSIZE)
 117                         mb = m_getcl(how, type, (flags & M_PKTHDR));
 118                 else if (flags & M_PKTHDR)
 119                         mb = m_gethdr(how, type);
 120                 else
 121                         mb = m_get(how, type);
 122
 123                 /* Fail the whole operation if one mbuf can't be allocated. */
 124                 if (mb == NULL) {
 125                         if (nm != NULL)
 126                                 m_freem(nm);
 127                         return (NULL);
 128                 }
 129
 130                 /* Book keeping. */
 131                 len -= (mb->m_flags & M_EXT) ? mb->m_ext.ext_size :
 132                         ((mb->m_flags & M_PKTHDR) ? MHLEN : MLEN);
 133                 if (mtail != NULL)
 134                         mtail->m_next = mb;
 135                 else
 136                         nm = mb;
 137                 mtail = mb;
 138                 flags &= ~M_PKTHDR;     /* Only valid on the first mbuf. */
 139         }
 140         if (flags & M_EOR)
 141                 mtail->m_flags |= M_EOR;  /* Only valid on the last mbuf. */
 142
 143         /* If mbuf was supplied, append new chain to the end of it. */
 144         if (m != NULL) {
 145                 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next)
 146                         ;
 147                 mtail->m_next = nm;
 148                 mtail->m_flags &= ~M_EOR;
 149         } else
 150                 m = nm;
 151
 152         return (m);
 153 }
 154
 155 /*
 156  * Free an entire chain of mbufs and associated external buffers, if
 157  * applicable.
 158  */
 159 void
 160 m_freem(struct mbuf *mb)
 161 {
 162
 163         while (mb != NULL)
 164                 mb = m_free(mb);
 165 }
 166
 167 /*-
 168  * Configure a provided mbuf to refer to the provided external storage
 169  * buffer and setup a reference count for said buffer.  If the setting
 170  * up of the reference count fails, the M_EXT bit will not be set.  If
 171  * successfull, the M_EXT bit is set in the mbuf's flags.
 172  *
 173  * Arguments:
 174  *    mb     The existing mbuf to which to attach the provided buffer.
 175  *    buf    The address of the provided external storage buffer.
 176  *    size   The size of the provided buffer.
 177  *    freef  A pointer to a routine that is responsible for freeing the
 178  *           provided external storage buffer.
 179  *    args   A pointer to an argument structure (of any type) to be passed
 180  *           to the provided freef routine (may be NULL).
 181  *    flags  Any other flags to be passed to the provided mbuf.
 182  *    type   The type that the external storage buffer should be
 183  *           labeled with.
 184  *
 185  * Returns:
 186  *    Nothing.
 187  */
 188 void
 189 m_extadd(struct mbuf *mb, caddr_t buf, u_int size,
 190     void (*freef)(void *, void *), void *arg1, void *arg2, int flags, int type)
 191 {
 192         KASSERT(type != EXT_CLUSTER, ("%s: EXT_CLUSTER not allowed", __func__));
 193
 194         if (type != EXT_EXTREF)
 195                 mb->m_ext.ref_cnt = (u_int *)uma_zalloc(zone_ext_refcnt, M_NOWAIT);
 196         if (mb->m_ext.ref_cnt != NULL) {
 197                 *(mb->m_ext.ref_cnt) = 1;
 198                 mb->m_flags |= (M_EXT | flags);
 199                 mb->m_ext.ext_buf = buf;
 200                 mb->m_data = mb->m_ext.ext_buf;
 201                 mb->m_ext.ext_size = size;
 202                 mb->m_ext.ext_free = freef;
 203                 mb->m_ext.ext_arg1 = arg1;
 204                 mb->m_ext.ext_arg2 = arg2;
 205                 mb->m_ext.ext_type = type;
 206         }
 207 }
 208
 209 /*
 210  * Non-directly-exported function to clean up after mbufs with M_EXT
 211  * storage attached to them if the reference count hits 1.
 212  */
 213 void
 214 mb_free_ext(struct mbuf *m)
 215 {
 216         int skipmbuf;
 217
 218         KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
 219         KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
 220
 221
 222         /*
 223          * check if the header is embedded in the cluster
 224          */
 225         skipmbuf = (m->m_flags & M_NOFREE);
 226
 227         /* Free attached storage if this mbuf is the only reference to it. */
 228         if (*(m->m_ext.ref_cnt) == 1 ||
 229             atomic_fetchadd_int(m->m_ext.ref_cnt, -1) == 1) {
 230                 switch (m->m_ext.ext_type) {
 231                 case EXT_PACKET:        /* The packet zone is special. */
 232                         if (*(m->m_ext.ref_cnt) == 0)
 233                                 *(m->m_ext.ref_cnt) = 1;
 234                         uma_zfree(zone_pack, m);
 235                         return;         /* Job done. */
 236                 case EXT_CLUSTER:
 237                         uma_zfree(zone_clust, m->m_ext.ext_buf);
 238                         break;
 239                 case EXT_JUMBOP:
 240                         uma_zfree(zone_jumbop, m->m_ext.ext_buf);
 241                         break;
 242                 case EXT_JUMBO9:
 243                         uma_zfree(zone_jumbo9, m->m_ext.ext_buf);
 244                         break;
 245                 case EXT_JUMBO16:
 246                         uma_zfree(zone_jumbo16, m->m_ext.ext_buf);
 247                         break;
 248                 case EXT_SFBUF:
 249                 case EXT_NET_DRV:
 250                 case EXT_MOD_TYPE:
 251                 case EXT_DISPOSABLE:
 252                         *(m->m_ext.ref_cnt) = 0;
 253                         uma_zfree(zone_ext_refcnt, __DEVOLATILE(u_int *,
 254                                 m->m_ext.ref_cnt));
 255                         /* FALLTHROUGH */
 256                 case EXT_EXTREF:
 257                         KASSERT(m->m_ext.ext_free != NULL,
 258                                 ("%s: ext_free not set", __func__));
 259                         (*(m->m_ext.ext_free))(m->m_ext.ext_arg1,
 260                             m->m_ext.ext_arg2);
 261                         break;
 262                 default:
 263                         KASSERT(m->m_ext.ext_type == 0,
 264                                 ("%s: unknown ext_type", __func__));
 265                 }
 266         }
 267         if (skipmbuf)
 268                 return;
 269
 270         /*
 271          * Free this mbuf back to the mbuf zone with all m_ext
 272          * information purged.
 273          */
 274         m->m_ext.ext_buf = NULL;
 275         m->m_ext.ext_free = NULL;
 276         m->m_ext.ext_arg1 = NULL;
 277         m->m_ext.ext_arg2 = NULL;
 278         m->m_ext.ref_cnt = NULL;
 279         m->m_ext.ext_size = 0;
 280         m->m_ext.ext_type = 0;
 281         m->m_flags &= ~M_EXT;
 282         uma_zfree(zone_mbuf, m);
 283 }
 284
 285 /*
 286  * Attach the the cluster from *m to *n, set up m_ext in *n
 287  * and bump the refcount of the cluster.
 288  */
 289 static void
 290 mb_dupcl(struct mbuf *n, struct mbuf *m)
 291 {
 292         KASSERT((m->m_flags & M_EXT) == M_EXT, ("%s: M_EXT not set", __func__));
 293         KASSERT(m->m_ext.ref_cnt != NULL, ("%s: ref_cnt not set", __func__));
 294         KASSERT((n->m_flags & M_EXT) == 0, ("%s: M_EXT set", __func__));
 295
 296         if (*(m->m_ext.ref_cnt) == 1)
 297                 *(m->m_ext.ref_cnt) += 1;
 298         else
 299                 atomic_add_int(m->m_ext.ref_cnt, 1);
 300         n->m_ext.ext_buf = m->m_ext.ext_buf;
 301         n->m_ext.ext_free = m->m_ext.ext_free;
 302         n->m_ext.ext_arg1 = m->m_ext.ext_arg1;
 303         n->m_ext.ext_arg2 = m->m_ext.ext_arg2;
 304         n->m_ext.ext_size = m->m_ext.ext_size;
 305         n->m_ext.ref_cnt = m->m_ext.ref_cnt;
 306         n->m_ext.ext_type = m->m_ext.ext_type;
 307         n->m_flags |= M_EXT;
 308 }
 309
 310 /*
 311  * Clean up mbuf (chain) from any tags and packet headers.
 312  * If "all" is set then the first mbuf in the chain will be
 313  * cleaned too.
 314  */
 315 void
 316 m_demote(struct mbuf *m0, int all)
 317 {
 318         struct mbuf *m;
 319
 320         for (m = all ? m0 : m0->m_next; m != NULL; m = m->m_next) {
 321                 if (m->m_flags & M_PKTHDR) {
 322                         m_tag_delete_chain(m, NULL);
 323                         m->m_flags &= ~M_PKTHDR;
 324                         bzero(&m->m_pkthdr, sizeof(struct pkthdr));
 325                 }
 326                 if (m->m_type == MT_HEADER)
 327                         m->m_type = MT_DATA;
 328                 if (m != m0 && m->m_nextpkt != NULL)
 329                         m->m_nextpkt = NULL;
 330                 m->m_flags = m->m_flags & (M_EXT|M_EOR|M_RDONLY|M_FREELIST);
 331         }
 332 }
 333
 334 /*
 335  * Sanity checks on mbuf (chain) for use in KASSERT() and general
 336  * debugging.
 337  * Returns 0 or panics when bad and 1 on all tests passed.
 338  * Sanitize, 0 to run M_SANITY_ACTION, 1 to garble things so they
 339  * blow up later.
 340  */
 341 int
 342 m_sanity(struct mbuf *m0, int sanitize)
 343 {
 344         struct mbuf *m;
 345         caddr_t a, b;
 346         int pktlen = 0;
 347
 348 #ifdef INVARIANTS
 349 #define M_SANITY_ACTION(s)      panic("mbuf %p: " s, m)
 350 #else
 351 #define M_SANITY_ACTION(s)      printf("mbuf %p: " s, m)
 352 #endif
 353
 354         for (m = m0; m != NULL; m = m->m_next) {
 355                 /*
 356                  * Basic pointer checks.  If any of these fails then some
 357                  * unrelated kernel memory before or after us is trashed.
 358                  * No way to recover from that.
 359                  */
 360                 a = ((m->m_flags & M_EXT) ? m->m_ext.ext_buf :
 361                         ((m->m_flags & M_PKTHDR) ? (caddr_t)(&m->m_pktdat) :
 362                          (caddr_t)(&m->m_dat)) );
 363                 b = (caddr_t)(a + (m->m_flags & M_EXT ? m->m_ext.ext_size :
 364                         ((m->m_flags & M_PKTHDR) ? MHLEN : MLEN)));
 365                 if ((caddr_t)m->m_data < a)
 366                         M_SANITY_ACTION("m_data outside mbuf data range left");
 367                 if ((caddr_t)m->m_data > b)
 368                         M_SANITY_ACTION("m_data outside mbuf data range right");
 369                 if ((caddr_t)m->m_data + m->m_len > b)
 370                         M_SANITY_ACTION("m_data + m_len exeeds mbuf space");
 371                 if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.header) {
 372                         if ((caddr_t)m->m_pkthdr.header < a ||
 373                             (caddr_t)m->m_pkthdr.header > b)
 374                                 M_SANITY_ACTION("m_pkthdr.header outside mbuf data range");
 375                 }
 376
 377                 /* m->m_nextpkt may only be set on first mbuf in chain. */
 378                 if (m != m0 && m->m_nextpkt != NULL) {
 379                         if (sanitize) {
 380                                 m_freem(m->m_nextpkt);
 381                                 m->m_nextpkt = (struct mbuf *)0xDEADC0DE;
 382                         } else
 383                                 M_SANITY_ACTION("m->m_nextpkt on in-chain mbuf");
 384                 }
 385
 386                 /* packet length (not mbuf length!) calculation */
 387                 if (m0->m_flags & M_PKTHDR)
 388                         pktlen += m->m_len;
 389
 390                 /* m_tags may only be attached to first mbuf in chain. */
 391                 if (m != m0 && m->m_flags & M_PKTHDR &&
 392                     !SLIST_EMPTY(&m->m_pkthdr.tags)) {
 393                         if (sanitize) {
 394                                 m_tag_delete_chain(m, NULL);
 395                                 /* put in 0xDEADC0DE perhaps? */
 396                         } else
 397                                 M_SANITY_ACTION("m_tags on in-chain mbuf");
 398                 }
 399
 400                 /* M_PKTHDR may only be set on first mbuf in chain */
 401                 if (m != m0 && m->m_flags & M_PKTHDR) {
 402                         if (sanitize) {
 403                                 bzero(&m->m_pkthdr, sizeof(m->m_pkthdr));
 404                                 m->m_flags &= ~M_PKTHDR;
 405                                 /* put in 0xDEADCODE and leave hdr flag in */
 406                         } else
 407                                 M_SANITY_ACTION("M_PKTHDR on in-chain mbuf");
 408                 }
 409         }
 410         m = m0;
 411         if (pktlen && pktlen != m->m_pkthdr.len) {
 412                 if (sanitize)
 413                         m->m_pkthdr.len = 0;
 414                 else
 415                         M_SANITY_ACTION("m_pkthdr.len != mbuf chain length");
 416         }
 417         return 1;
 418
 419 #undef  M_SANITY_ACTION
 420 }
 421
 422
 423 /*
 424  * "Move" mbuf pkthdr from "from" to "to".
 425  * "from" must have M_PKTHDR set, and "to" must be empty.
 426  */
 427 void
 428 m_move_pkthdr(struct mbuf *to, struct mbuf *from)
 429 {
 430
 431 #if 0
 432         /* see below for why these are not enabled */
 433         M_ASSERTPKTHDR(to);
 434         /* Note: with MAC, this may not be a good assertion. */
 435         KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags),
 436             ("m_move_pkthdr: to has tags"));
 437 #endif
 438 #ifdef MAC
 439         /*
 440          * XXXMAC: It could be this should also occur for non-MAC?
 441          */
 442         if (to->m_flags & M_PKTHDR)
 443                 m_tag_delete_chain(to, NULL);
 444 #endif
 445         to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
 446         if ((to->m_flags & M_EXT) == 0)
 447                 to->m_data = to->m_pktdat;
 448         to->m_pkthdr = from->m_pkthdr;          /* especially tags */
 449         SLIST_INIT(&from->m_pkthdr.tags);       /* purge tags from src */
 450         from->m_flags &= ~M_PKTHDR;
 451 }
 452
 453 /*
 454  * Duplicate "from"'s mbuf pkthdr in "to".
 455  * "from" must have M_PKTHDR set, and "to" must be empty.
 456  * In particular, this does a deep copy of the packet tags.
 457  */
 458 int
 459 m_dup_pkthdr(struct mbuf *to, struct mbuf *from, int how)
 460 {
 461
 462 #if 0
 463         /*
 464          * The mbuf allocator only initializes the pkthdr
 465          * when the mbuf is allocated with MGETHDR. Many users
 466          * (e.g. m_copy*, m_prepend) use MGET and then
 467          * smash the pkthdr as needed causing these
 468          * assertions to trip.  For now just disable them.
 469          */
 470         M_ASSERTPKTHDR(to);
 471         /* Note: with MAC, this may not be a good assertion. */
 472         KASSERT(SLIST_EMPTY(&to->m_pkthdr.tags), ("m_dup_pkthdr: to has tags"));
 473 #endif
 474         MBUF_CHECKSLEEP(how);
 475 #ifdef MAC
 476         if (to->m_flags & M_PKTHDR)
 477                 m_tag_delete_chain(to, NULL);
 478 #endif
 479         to->m_flags = (from->m_flags & M_COPYFLAGS) | (to->m_flags & M_EXT);
 480         if ((to->m_flags & M_EXT) == 0)
 481                 to->m_data = to->m_pktdat;
 482         to->m_pkthdr = from->m_pkthdr;
 483         SLIST_INIT(&to->m_pkthdr.tags);
 484         return (m_tag_copy_chain(to, from, MBTOM(how)));
 485 }
 486
 487 /*
 488  * Lesser-used path for M_PREPEND:
 489  * allocate new mbuf to prepend to chain,
 490  * copy junk along.
 491  */
 492 struct mbuf *
 493 m_prepend(struct mbuf *m, int len, int how)
 494 {
 495         struct mbuf *mn;
 496
 497         if (m->m_flags & M_PKTHDR)
 498                 MGETHDR(mn, how, m->m_type);
 499         else
 500                 MGET(mn, how, m->m_type);
 501         if (mn == NULL) {
 502                 m_freem(m);
 503                 return (NULL);
 504         }
 505         if (m->m_flags & M_PKTHDR)
 506                 M_MOVE_PKTHDR(mn, m);
 507         mn->m_next = m;
 508         m = mn;
 509         if(m->m_flags & M_PKTHDR) {
 510                 if (len < MHLEN)
 511                         MH_ALIGN(m, len);
 512         } else {
 513                 if (len < MLEN)
 514                         M_ALIGN(m, len);
 515         }
 516         m->m_len = len;
 517         return (m);
 518 }
 519
 520 /*
 521  * Make a copy of an mbuf chain starting "off0" bytes from the beginning,
 522  * continuing for "len" bytes.  If len is M_COPYALL, copy to end of mbuf.
 523  * The wait parameter is a choice of M_WAIT/M_DONTWAIT from caller.
 524  * Note that the copy is read-only, because clusters are not copied,
 525  * only their reference counts are incremented.
 526  */
 527 struct mbuf *
 528 m_copym(struct mbuf *m, int off0, int len, int wait)
 529 {
 530         struct mbuf *n, **np;
 531         int off = off0;
 532         struct mbuf *top;
 533         int copyhdr = 0;
 534
 535         KASSERT(off >= 0, ("m_copym, negative off %d", off));
 536         KASSERT(len >= 0, ("m_copym, negative len %d", len));
 537         MBUF_CHECKSLEEP(wait);
 538         if (off == 0 && m->m_flags & M_PKTHDR)
 539                 copyhdr = 1;
 540         while (off > 0) {
 541                 KASSERT(m != NULL, ("m_copym, offset > size of mbuf chain"));
 542                 if (off < m->m_len)
 543                         break;
 544                 off -= m->m_len;
 545                 m = m->m_next;
 546         }
 547         np = &top;
 548         top = 0;
 549         while (len > 0) {
 550                 if (m == NULL) {
 551                         KASSERT(len == M_COPYALL,
 552                             ("m_copym, length > size of mbuf chain"));
 553                         break;
 554                 }
 555                 if (copyhdr)
 556                         MGETHDR(n, wait, m->m_type);
 557                 else
 558                         MGET(n, wait, m->m_type);
 559                 *np = n;
 560                 if (n == NULL)
 561                         goto nospace;
 562                 if (copyhdr) {
 563                         if (!m_dup_pkthdr(n, m, wait))
 564                                 goto nospace;
 565                         if (len == M_COPYALL)
 566                                 n->m_pkthdr.len -= off0;
 567                         else
 568                                 n->m_pkthdr.len = len;
 569                         copyhdr = 0;
 570                 }
 571                 n->m_len = min(len, m->m_len - off);
 572                 if (m->m_flags & M_EXT) {
 573                         n->m_data = m->m_data + off;
 574                         mb_dupcl(n, m);
 575                 } else
 576                         bcopy(mtod(m, caddr_t)+off, mtod(n, caddr_t),
 577                             (u_int)n->m_len);
 578                 if (len != M_COPYALL)
 579                         len -= n->m_len;
 580                 off = 0;
 581                 m = m->m_next;
 582                 np = &n->m_next;
 583         }
 584         if (top == NULL)
 585                 mbstat.m_mcfail++;      /* XXX: No consistency. */
 586
 587         return (top);
 588 nospace:
 589         m_freem(top);
 590         mbstat.m_mcfail++;      /* XXX: No consistency. */
 591         return (NULL);
 592 }
 593
 594 /*
 595  * Returns mbuf chain with new head for the prepending case.
 596  * Copies from mbuf (chain) n from off for len to mbuf (chain) m
 597  * either prepending or appending the data.
 598  * The resulting mbuf (chain) m is fully writeable.
 599  * m is destination (is made writeable)
 600  * n is source, off is offset in source, len is len from offset
 601  * dir, 0 append, 1 prepend
 602  * how, wait or nowait
 603  */
 604
 605 static int
 606 m_bcopyxxx(void *s, void *t, u_int len)
 607 {
 608         bcopy(s, t, (size_t)len);
 609         return 0;
 610 }
 611
 612 struct mbuf *
 613 m_copymdata(struct mbuf *m, struct mbuf *n, int off, int len,
 614     int prep, int how)
 615 {
 616         struct mbuf *mm, *x, *z, *prev = NULL;
 617         caddr_t p;
 618         int i, nlen = 0;
 619         caddr_t buf[MLEN];
 620
 621         KASSERT(m != NULL && n != NULL, ("m_copymdata, no target or source"));
 622         KASSERT(off >= 0, ("m_copymdata, negative off %d", off));
 623         KASSERT(len >= 0, ("m_copymdata, negative len %d", len));
 624         KASSERT(prep == 0 || prep == 1, ("m_copymdata, unknown direction %d", prep));
 625
 626         mm = m;
 627         if (!prep) {
 628                 while(mm->m_next) {
 629                         prev = mm;
 630                         mm = mm->m_next;
 631                 }
 632         }
 633         for (z = n; z != NULL; z = z->m_next)
 634                 nlen += z->m_len;
 635         if (len == M_COPYALL)
 636                 len = nlen - off;
 637         if (off + len > nlen || len < 1)
 638                 return NULL;
 639
 640         if (!M_WRITABLE(mm)) {
 641                 /* XXX: Use proper m_xxx function instead. */
 642                 x = m_getcl(how, MT_DATA, mm->m_flags);
 643                 if (x == NULL)
 644                         return NULL;
 645                 bcopy(mm->m_ext.ext_buf, x->m_ext.ext_buf, x->m_ext.ext_size);
 646                 p = x->m_ext.ext_buf + (mm->m_data - mm->m_ext.ext_buf);
 647                 x->m_data = p;
 648                 mm->m_next = NULL;
 649                 if (mm != m)
 650                         prev->m_next = x;
 651                 m_free(mm);
 652                 mm = x;
 653         }
 654
 655         /*
 656          * Append/prepend the data.  Allocating mbufs as necessary.
 657          */
 658         /* Shortcut if enough free space in first/last mbuf. */
 659         if (!prep && M_TRAILINGSPACE(mm) >= len) {
 660                 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t) +
 661                          mm->m_len);
 662                 mm->m_len += len;
 663                 mm->m_pkthdr.len += len;
 664                 return m;
 665         }
 666         if (prep && M_LEADINGSPACE(mm) >= len) {
 667                 mm->m_data = mtod(mm, caddr_t) - len;
 668                 m_apply(n, off, len, m_bcopyxxx, mtod(mm, caddr_t));
 669                 mm->m_len += len;
 670                 mm->m_pkthdr.len += len;
 671                 return mm;
 672         }
 673
 674         /* Expand first/last mbuf to cluster if possible. */
 675         if (!prep && !(mm->m_flags & M_EXT) && len > M_TRAILINGSPACE(mm)) {
 676                 bcopy(mm->m_data, &buf, mm->m_len);
 677                 m_clget(mm, how);
 678                 if (!(mm->m_flags & M_EXT))
 679                         return NULL;
 680                 bcopy(&buf, mm->m_ext.ext_buf, mm->m_len);
 681                 mm->m_data = mm->m_ext.ext_buf;
 682                 mm->m_pkthdr.header = NULL;
 683         }
 684         if (prep && !(mm->m_flags & M_EXT) && len > M_LEADINGSPACE(mm)) {
 685                 bcopy(mm->m_data, &buf, mm->m_len);
 686                 m_clget(mm, how);
 687                 if (!(mm->m_flags & M_EXT))
 688                         return NULL;
 689                 bcopy(&buf, (caddr_t *)mm->m_ext.ext_buf +
 690                        mm->m_ext.ext_size - mm->m_len, mm->m_len);
 691                 mm->m_data = (caddr_t)mm->m_ext.ext_buf +
 692                               mm->m_ext.ext_size - mm->m_len;
 693                 mm->m_pkthdr.header = NULL;
 694         }
 695
 696         /* Append/prepend as many mbuf (clusters) as necessary to fit len. */
 697         if (!prep && len > M_TRAILINGSPACE(mm)) {
 698                 if (!m_getm(mm, len - M_TRAILINGSPACE(mm), how, MT_DATA))
 699                         return NULL;
 700         }
 701         if (prep && len > M_LEADINGSPACE(mm)) {
 702                 if (!(z = m_getm(NULL, len - M_LEADINGSPACE(mm), how, MT_DATA)))
 703                         return NULL;
 704                 i = 0;
 705                 for (x = z; x != NULL; x = x->m_next) {
 706                         i += x->m_flags & M_EXT ? x->m_ext.ext_size :
 707                               (x->m_flags & M_PKTHDR ? MHLEN : MLEN);
 708                         if (!x->m_next)
 709                                 break;
 710                 }
 711                 z->m_data += i - len;
 712                 m_move_pkthdr(mm, z);
 713                 x->m_next = mm;
 714                 mm = z;
 715         }
 716
 717         /* Seek to start position in source mbuf. Optimization for long chains. */
 718         while (off > 0) {
 719                 if (off < n->m_len)
 720                         break;
 721                 off -= n->m_len;
 722                 n = n->m_next;
 723         }
 724
 725         /* Copy data into target mbuf. */
 726         z = mm;
 727         while (len > 0) {
 728                 KASSERT(z != NULL, ("m_copymdata, falling off target edge"));
 729                 i = M_TRAILINGSPACE(z);
 730                 m_apply(n, off, i, m_bcopyxxx, mtod(z, caddr_t) + z->m_len);
 731                 z->m_len += i;
 732                 /* fixup pkthdr.len if necessary */
 733                 if ((prep ? mm : m)->m_flags & M_PKTHDR)
 734                         (prep ? mm : m)->m_pkthdr.len += i;
 735                 off += i;
 736                 len -= i;
 737                 z = z->m_next;
 738         }
 739         return (prep ? mm : m);
 740 }
 741
 742 /*
 743  * Copy an entire packet, including header (which must be present).
 744  * An optimization of the common case `m_copym(m, 0, M_COPYALL, how)'.
 745  * Note that the copy is read-only, because clusters are not copied,
 746  * only their reference counts are incremented.
 747  * Preserve alignment of the first mbuf so if the creator has left
 748  * some room at the beginning (e.g. for inserting protocol headers)
 749  * the copies still have the room available.
 750  */
 751 struct mbuf *
 752 m_copypacket(struct mbuf *m, int how)
 753 {
 754         struct mbuf *top, *n, *o;
 755
 756         MBUF_CHECKSLEEP(how);
 757         MGET(n, how, m->m_type);
 758         top = n;
 759         if (n == NULL)
 760                 goto nospace;
 761
 762         if (!m_dup_pkthdr(n, m, how))
 763                 goto nospace;
 764         n->m_len = m->m_len;
 765         if (m->m_flags & M_EXT) {
 766                 n->m_data = m->m_data;
 767                 mb_dupcl(n, m);
 768         } else {
 769                 n->m_data = n->m_pktdat + (m->m_data - m->m_pktdat );
 770                 bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
 771         }
 772
 773         m = m->m_next;
 774         while (m) {
 775                 MGET(o, how, m->m_type);
 776                 if (o == NULL)
 777                         goto nospace;
 778
 779                 n->m_next = o;
 780                 n = n->m_next;
 781
 782                 n->m_len = m->m_len;
 783                 if (m->m_flags & M_EXT) {
 784                         n->m_data = m->m_data;
 785                         mb_dupcl(n, m);
 786                 } else {
 787                         bcopy(mtod(m, char *), mtod(n, char *), n->m_len);
 788                 }
 789
 790                 m = m->m_next;
 791         }
 792         return top;
 793 nospace:
 794         m_freem(top);
 795         mbstat.m_mcfail++;      /* XXX: No consistency. */
 796         return (NULL);
 797 }
 798
 799 /*
 800  * Copy data from an mbuf chain starting "off" bytes from the beginning,
 801  * continuing for "len" bytes, into the indicated buffer.
 802  */
 803 void
 804 m_copydata(const struct mbuf *m, int off, int len, caddr_t cp)
 805 {
 806         u_int count;
 807
 808         KASSERT(off >= 0, ("m_copydata, negative off %d", off));
 809         KASSERT(len >= 0, ("m_copydata, negative len %d", len));
 810         while (off > 0) {
 811                 KASSERT(m != NULL, ("m_copydata, offset > size of mbuf chain"));
 812                 if (off < m->m_len)
 813                         break;
 814                 off -= m->m_len;
 815                 m = m->m_next;
 816         }
 817         while (len > 0) {
 818                 KASSERT(m != NULL, ("m_copydata, length > size of mbuf chain"));
 819                 count = min(m->m_len - off, len);
 820                 bcopy(mtod(m, caddr_t) + off, cp, count);
 821                 len -= count;
 822                 cp += count;
 823                 off = 0;
 824                 m = m->m_next;
 825         }
 826 }
 827
 828 /*
 829  * Copy a packet header mbuf chain into a completely new chain, including
 830  * copying any mbuf clusters.  Use this instead of m_copypacket() when
 831  * you need a writable copy of an mbuf chain.
 832  */
 833 struct mbuf *
 834 m_dup(struct mbuf *m, int how)
 835 {
 836         struct mbuf **p, *top = NULL;
 837         int remain, moff, nsize;
 838
 839         MBUF_CHECKSLEEP(how);
 840         /* Sanity check */
 841         if (m == NULL)
 842                 return (NULL);
 843         M_ASSERTPKTHDR(m);
 844
 845         /* While there's more data, get a new mbuf, tack it on, and fill it */
 846         remain = m->m_pkthdr.len;
 847         moff = 0;
 848         p = &top;
 849         while (remain > 0 || top == NULL) {     /* allow m->m_pkthdr.len == 0 */
 850                 struct mbuf *n;
 851
 852                 /* Get the next new mbuf */
 853                 if (remain >= MINCLSIZE) {
 854                         n = m_getcl(how, m->m_type, 0);
 855                         nsize = MCLBYTES;
 856                 } else {
 857                         n = m_get(how, m->m_type);
 858                         nsize = MLEN;
 859                 }
 860                 if (n == NULL)
 861                         goto nospace;
 862
 863                 if (top == NULL) {              /* First one, must be PKTHDR */
 864                         if (!m_dup_pkthdr(n, m, how)) {
 865                                 m_free(n);
 866                                 goto nospace;
 867                         }
 868                         if ((n->m_flags & M_EXT) == 0)
 869                                 nsize = MHLEN;
 870                 }
 871                 n->m_len = 0;
 872
 873                 /* Link it into the new chain */
 874                 *p = n;
 875                 p = &n->m_next;
 876
 877                 /* Copy data from original mbuf(s) into new mbuf */
 878                 while (n->m_len < nsize && m != NULL) {
 879                         int chunk = min(nsize - n->m_len, m->m_len - moff);
 880
 881                         bcopy(m->m_data + moff, n->m_data + n->m_len, chunk);
 882                         moff += chunk;
 883                         n->m_len += chunk;
 884                         remain -= chunk;
 885                         if (moff == m->m_len) {
 886                                 m = m->m_next;
 887                                 moff = 0;
 888                         }
 889                 }
 890
 891                 /* Check correct total mbuf length */
 892                 KASSERT((remain > 0 && m != NULL) || (remain == 0 && m == NULL),
 893                         ("%s: bogus m_pkthdr.len", __func__));
 894         }
 895         return (top);
 896
 897 nospace:
 898         m_freem(top);
 899         mbstat.m_mcfail++;      /* XXX: No consistency. */
 900         return (NULL);
 901 }
 902
 903 /*
 904  * Concatenate mbuf chain n to m.
 905  * Both chains must be of the same type (e.g. MT_DATA).
 906  * Any m_pkthdr is not updated.
 907  */
 908 void
 909 m_cat(struct mbuf *m, struct mbuf *n)
 910 {
 911         while (m->m_next)
 912                 m = m->m_next;
 913         while (n) {
 914                 if (m->m_flags & M_EXT ||
 915                     m->m_data + m->m_len + n->m_len >= &m->m_dat[MLEN]) {
 916                         /* just join the two chains */
 917                         m->m_next = n;
 918                         return;
 919                 }
 920                 /* splat the data from one into the other */
 921                 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
 922                     (u_int)n->m_len);
 923                 m->m_len += n->m_len;
 924                 n = m_free(n);
 925         }
 926 }
 927
 928 void
 929 m_adj(struct mbuf *mp, int req_len)
 930 {
 931         int len = req_len;
 932         struct mbuf *m;
 933         int count;
 934
 935         if ((m = mp) == NULL)
 936                 return;
 937         if (len >= 0) {
 938                 /*
 939                  * Trim from head.
 940                  */
 941                 while (m != NULL && len > 0) {
 942                         if (m->m_len <= len) {
 943                                 len -= m->m_len;
 944                                 m->m_len = 0;
 945                                 m = m->m_next;
 946                         } else {
 947                                 m->m_len -= len;
 948                                 m->m_data += len;
 949                                 len = 0;
 950                         }
 951                 }
 952                 m = mp;
 953                 if (mp->m_flags & M_PKTHDR)
 954                         m->m_pkthdr.len -= (req_len - len);
 955         } else {
 956                 /*
 957                  * Trim from tail.  Scan the mbuf chain,
 958                  * calculating its length and finding the last mbuf.
 959                  * If the adjustment only affects this mbuf, then just
 960                  * adjust and return.  Otherwise, rescan and truncate
 961                  * after the remaining size.
 962                  */
 963                 len = -len;
 964                 count = 0;
 965                 for (;;) {
 966                         count += m->m_len;
 967                         if (m->m_next == (struct mbuf *)0)
 968                                 break;
 969                         m = m->m_next;
 970                 }
 971                 if (m->m_len >= len) {
 972                         m->m_len -= len;
 973                         if (mp->m_flags & M_PKTHDR)
 974                                 mp->m_pkthdr.len -= len;
 975                         return;
 976                 }
 977                 count -= len;
 978                 if (count < 0)
 979                         count = 0;
 980                 /*
 981                  * Correct length for chain is "count".
 982                  * Find the mbuf with last data, adjust its length,
 983                  * and toss data from remaining mbufs on chain.
 984                  */
 985                 m = mp;
 986                 if (m->m_flags & M_PKTHDR)
 987                         m->m_pkthdr.len = count;
 988                 for (; m; m = m->m_next) {
 989                         if (m->m_len >= count) {
 990                                 m->m_len = count;
 991                                 if (m->m_next != NULL) {
 992                                         m_freem(m->m_next);
 993                                         m->m_next = NULL;
 994                                 }
 995                                 break;
 996                         }
 997                         count -= m->m_len;
 998                 }
 999         }
1000 }
1001
1002 /*
1003  * Rearange an mbuf chain so that len bytes are contiguous
1004  * and in the data area of an mbuf (so that mtod and dtom
1005  * will work for a structure of size len).  Returns the resulting
1006  * mbuf chain on success, frees it and returns null on failure.
1007  * If there is room, it will add up to max_protohdr-len extra bytes to the
1008  * contiguous region in an attempt to avoid being called next time.
1009  */
1010 struct mbuf *
1011 m_pullup(struct mbuf *n, int len)
1012 {
1013         struct mbuf *m;
1014         int count;
1015         int space;
1016
1017         /*
1018          * If first mbuf has no cluster, and has room for len bytes
1019          * without shifting current data, pullup into it,
1020          * otherwise allocate a new mbuf to prepend to the chain.
1021          */
1022         if ((n->m_flags & M_EXT) == 0 &&
1023             n->m_data + len < &n->m_dat[MLEN] && n->m_next) {
1024                 if (n->m_len >= len)
1025                         return (n);
1026                 m = n;
1027                 n = n->m_next;
1028                 len -= m->m_len;
1029         } else {
1030                 if (len > MHLEN)
1031                         goto bad;
1032                 MGET(m, M_DONTWAIT, n->m_type);
1033                 if (m == NULL)
1034                         goto bad;
1035                 m->m_len = 0;
1036                 if (n->m_flags & M_PKTHDR)
1037                         M_MOVE_PKTHDR(m, n);
1038         }
1039         space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1040         do {
1041                 count = min(min(max(len, max_protohdr), space), n->m_len);
1042                 bcopy(mtod(n, caddr_t), mtod(m, caddr_t) + m->m_len,
1043                   (u_int)count);
1044                 len -= count;
1045                 m->m_len += count;
1046                 n->m_len -= count;
1047                 space -= count;
1048                 if (n->m_len)
1049                         n->m_data += count;
1050                 else
1051                         n = m_free(n);
1052         } while (len > 0 && n);
1053         if (len > 0) {
1054                 (void) m_free(m);
1055                 goto bad;
1056         }
1057         m->m_next = n;
1058         return (m);
1059 bad:
1060         m_freem(n);
1061         mbstat.m_mpfail++;      /* XXX: No consistency. */
1062         return (NULL);
1063 }
1064
1065 /*
1066  * Like m_pullup(), except a new mbuf is always allocated, and we allow
1067  * the amount of empty space before the data in the new mbuf to be specified
1068  * (in the event that the caller expects to prepend later).
1069  */
1070 int MSFail;
1071
1072 struct mbuf *
1073 m_copyup(struct mbuf *n, int len, int dstoff)
1074 {
1075         struct mbuf *m;
1076         int count, space;
1077
1078         if (len > (MHLEN - dstoff))
1079                 goto bad;
1080         MGET(m, M_DONTWAIT, n->m_type);
1081         if (m == NULL)
1082                 goto bad;
1083         m->m_len = 0;
1084         if (n->m_flags & M_PKTHDR)
1085                 M_MOVE_PKTHDR(m, n);
1086         m->m_data += dstoff;
1087         space = &m->m_dat[MLEN] - (m->m_data + m->m_len);
1088         do {
1089                 count = min(min(max(len, max_protohdr), space), n->m_len);
1090                 memcpy(mtod(m, caddr_t) + m->m_len, mtod(n, caddr_t),
1091                     (unsigned)count);
1092                 len -= count;
1093                 m->m_len += count;
1094                 n->m_len -= count;
1095                 space -= count;
1096                 if (n->m_len)
1097                         n->m_data += count;
1098                 else
1099                         n = m_free(n);
1100         } while (len > 0 && n);
1101         if (len > 0) {
1102                 (void) m_free(m);
1103                 goto bad;
1104         }
1105         m->m_next = n;
1106         return (m);
1107  bad:
1108         m_freem(n);
1109         MSFail++;
1110         return (NULL);
1111 }
1112
1113 /*
1114  * Partition an mbuf chain in two pieces, returning the tail --
1115  * all but the first len0 bytes.  In case of failure, it returns NULL and
1116  * attempts to restore the chain to its original state.
1117  *
1118  * Note that the resulting mbufs might be read-only, because the new
1119  * mbuf can end up sharing an mbuf cluster with the original mbuf if
1120  * the "breaking point" happens to lie within a cluster mbuf. Use the
1121  * M_WRITABLE() macro to check for this case.
1122  */
1123 struct mbuf *
1124 m_split(struct mbuf *m0, int len0, int wait)
1125 {
1126         struct mbuf *m, *n;
1127         u_int len = len0, remain;
1128
1129         MBUF_CHECKSLEEP(wait);
1130         for (m = m0; m && len > m->m_len; m = m->m_next)
1131                 len -= m->m_len;
1132         if (m == NULL)
1133                 return (NULL);
1134         remain = m->m_len - len;
1135         if (m0->m_flags & M_PKTHDR) {
1136                 MGETHDR(n, wait, m0->m_type);
1137                 if (n == NULL)
1138                         return (NULL);
1139                 n->m_pkthdr.rcvif = m0->m_pkthdr.rcvif;
1140                 n->m_pkthdr.len = m0->m_pkthdr.len - len0;
1141                 m0->m_pkthdr.len = len0;
1142                 if (m->m_flags & M_EXT)
1143                         goto extpacket;
1144                 if (remain > MHLEN) {
1145                         /* m can't be the lead packet */
1146                         MH_ALIGN(n, 0);
1147                         n->m_next = m_split(m, len, wait);
1148                         if (n->m_next == NULL) {
1149                                 (void) m_free(n);
1150                                 return (NULL);
1151                         } else {
1152                                 n->m_len = 0;
1153                                 return (n);
1154                         }
1155                 } else
1156                         MH_ALIGN(n, remain);
1157         } else if (remain == 0) {
1158                 n = m->m_next;
1159                 m->m_next = NULL;
1160                 return (n);
1161         } else {
1162                 MGET(n, wait, m->m_type);
1163                 if (n == NULL)
1164                         return (NULL);
1165                 M_ALIGN(n, remain);
1166         }
1167 extpacket:
1168         if (m->m_flags & M_EXT) {
1169                 n->m_data = m->m_data + len;
1170                 mb_dupcl(n, m);
1171         } else {
1172                 bcopy(mtod(m, caddr_t) + len, mtod(n, caddr_t), remain);
1173         }
1174         n->m_len = remain;
1175         m->m_len = len;
1176         n->m_next = m->m_next;
1177         m->m_next = NULL;
1178         return (n);
1179 }
1180 /*
1181  * Routine to copy from device local memory into mbufs.
1182  * Note that `off' argument is offset into first mbuf of target chain from
1183  * which to begin copying the data to.
1184  */
1185 struct mbuf *
1186 m_devget(char *buf, int totlen, int off, struct ifnet *ifp,
1187     void (*copy)(char *from, caddr_t to, u_int len))
1188 {
1189         struct mbuf *m;
1190         struct mbuf *top = NULL, **mp = &top;
1191         int len;
1192
1193         if (off < 0 || off > MHLEN)
1194                 return (NULL);
1195
1196         while (totlen > 0) {
1197                 if (top == NULL) {      /* First one, must be PKTHDR */
1198                         if (totlen + off >= MINCLSIZE) {
1199                                 m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
1200                                 len = MCLBYTES;
1201                         } else {
1202                                 m = m_gethdr(M_DONTWAIT, MT_DATA);
1203                                 len = MHLEN;
1204
1205                                 /* Place initial small packet/header at end of mbuf */
1206                                 if (m && totlen + off + max_linkhdr <= MLEN) {
1207                                         m->m_data += max_linkhdr;
1208                                         len -= max_linkhdr;
1209                                 }
1210                         }
1211                         if (m == NULL)
1212                                 return NULL;
1213                         m->m_pkthdr.rcvif = ifp;
1214                         m->m_pkthdr.len = totlen;
1215                 } else {
1216                         if (totlen + off >= MINCLSIZE) {
1217                                 m = m_getcl(M_DONTWAIT, MT_DATA, 0);
1218                                 len = MCLBYTES;
1219                         } else {
1220                                 m = m_get(M_DONTWAIT, MT_DATA);
1221                                 len = MLEN;
1222                         }
1223                         if (m == NULL) {
1224                                 m_freem(top);
1225                                 return NULL;
1226                         }
1227                 }
1228                 if (off) {
1229                         m->m_data += off;
1230                         len -= off;
1231                         off = 0;
1232                 }
1233                 m->m_len = len = min(totlen, len);
1234                 if (copy)
1235                         copy(buf, mtod(m, caddr_t), (u_int)len);
1236                 else
1237                         bcopy(buf, mtod(m, caddr_t), (u_int)len);
1238                 buf += len;
1239                 *mp = m;
1240                 mp = &m->m_next;
1241                 totlen -= len;
1242         }
1243         return (top);
1244 }
1245
1246 /*
1247  * Copy data from a buffer back into the indicated mbuf chain,
1248  * starting "off" bytes from the beginning, extending the mbuf
1249  * chain if necessary.
1250  */
1251 void
1252 m_copyback(struct mbuf *m0, int off, int len, c_caddr_t cp)
1253 {
1254         int mlen;
1255         struct mbuf *m = m0, *n;
1256         int totlen = 0;
1257
1258         if (m0 == NULL)
1259                 return;
1260         while (off > (mlen = m->m_len)) {
1261                 off -= mlen;
1262                 totlen += mlen;
1263                 if (m->m_next == NULL) {
1264                         n = m_get(M_DONTWAIT, m->m_type);
1265                         if (n == NULL)
1266                                 goto out;
1267                         bzero(mtod(n, caddr_t), MLEN);
1268                         n->m_len = min(MLEN, len + off);
1269                         m->m_next = n;
1270                 }
1271                 m = m->m_next;
1272         }
1273         while (len > 0) {
1274                 mlen = min (m->m_len - off, len);
1275                 bcopy(cp, off + mtod(m, caddr_t), (u_int)mlen);
1276                 cp += mlen;
1277                 len -= mlen;
1278                 mlen += off;
1279                 off = 0;
1280                 totlen += mlen;
1281                 if (len == 0)
1282                         break;
1283                 if (m->m_next == NULL) {
1284                         n = m_get(M_DONTWAIT, m->m_type);
1285                         if (n == NULL)
1286                                 break;
1287                         n->m_len = min(MLEN, len);
1288                         m->m_next = n;
1289                 }
1290                 m = m->m_next;
1291         }
1292 out:    if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
1293                 m->m_pkthdr.len = totlen;
1294 }
1295
1296 /*
1297  * Append the specified data to the indicated mbuf chain,
1298  * Extend the mbuf chain if the new data does not fit in
1299  * existing space.
1300  *
1301  * Return 1 if able to complete the job; otherwise 0.
1302  */
1303 int
1304 m_append(struct mbuf *m0, int len, c_caddr_t cp)
1305 {
1306         struct mbuf *m, *n;
1307         int remainder, space;
1308
1309         for (m = m0; m->m_next != NULL; m = m->m_next)
1310                 ;
1311         remainder = len;
1312         space = M_TRAILINGSPACE(m);
1313         if (space > 0) {
1314                 /*
1315                  * Copy into available space.
1316                  */
1317                 if (space > remainder)
1318                         space = remainder;
1319                 bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
1320                 m->m_len += space;
1321                 cp += space, remainder -= space;
1322         }
1323         while (remainder > 0) {
1324                 /*
1325                  * Allocate a new mbuf; could check space
1326                  * and allocate a cluster instead.
1327                  */
1328                 n = m_get(M_DONTWAIT, m->m_type);
1329                 if (n == NULL)
1330                         break;
1331                 n->m_len = min(MLEN, remainder);
1332                 bcopy(cp, mtod(n, caddr_t), n->m_len);
1333                 cp += n->m_len, remainder -= n->m_len;
1334                 m->m_next = n;
1335                 m = n;
1336         }
1337         if (m0->m_flags & M_PKTHDR)
1338                 m0->m_pkthdr.len += len - remainder;
1339         return (remainder == 0);
1340 }
1341
1342 /*
1343  * Apply function f to the data in an mbuf chain starting "off" bytes from
1344  * the beginning, continuing for "len" bytes.
1345  */
1346 int
1347 m_apply(struct mbuf *m, int off, int len,
1348     int (*f)(void *, void *, u_int), void *arg)
1349 {
1350         u_int count;
1351         int rval;
1352
1353         KASSERT(off >= 0, ("m_apply, negative off %d", off));
1354         KASSERT(len >= 0, ("m_apply, negative len %d", len));
1355         while (off > 0) {
1356                 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
1357                 if (off < m->m_len)
1358                         break;
1359                 off -= m->m_len;
1360                 m = m->m_next;
1361         }
1362         while (len > 0) {
1363                 KASSERT(m != NULL, ("m_apply, offset > size of mbuf chain"));
1364                 count = min(m->m_len - off, len);
1365                 rval = (*f)(arg, mtod(m, caddr_t) + off, count);
1366                 if (rval)
1367                         return (rval);
1368                 len -= count;
1369                 off = 0;
1370                 m = m->m_next;
1371         }
1372         return (0);
1373 }
1374
1375 /*
1376  * Return a pointer to mbuf/offset of location in mbuf chain.
1377  */
1378 struct mbuf *
1379 m_getptr(struct mbuf *m, int loc, int *off)
1380 {
1381
1382         while (loc >= 0) {
1383                 /* Normal end of search. */
1384                 if (m->m_len > loc) {
1385                         *off = loc;
1386                         return (m);
1387                 } else {
1388                         loc -= m->m_len;
1389                         if (m->m_next == NULL) {
1390                                 if (loc == 0) {
1391                                         /* Point at the end of valid data. */
1392                                         *off = m->m_len;
1393                                         return (m);
1394                                 }
1395                                 return (NULL);
1396                         }
1397                         m = m->m_next;
1398                 }
1399         }
1400         return (NULL);
1401 }
1402
1403 void
1404 m_print(const struct mbuf *m, int maxlen)
1405 {
1406         int len;
1407         int pdata;
1408         const struct mbuf *m2;
1409
1410         if (m->m_flags & M_PKTHDR)
1411                 len = m->m_pkthdr.len;
1412         else
1413                 len = -1;
1414         m2 = m;
1415         while (m2 != NULL && (len == -1 || len)) {
1416                 pdata = m2->m_len;
1417                 if (maxlen != -1 && pdata > maxlen)
1418                         pdata = maxlen;
1419                 printf("mbuf: %p len: %d, next: %p, %b%s", m2, m2->m_len,
1420                     m2->m_next, m2->m_flags, "\20\20freelist\17skipfw"
1421                     "\11proto5\10proto4\7proto3\6proto2\5proto1\4rdonly"
1422                     "\3eor\2pkthdr\1ext", pdata ? "" : "\n");
1423                 if (pdata)
1424                         printf(", %*D\n", pdata, (u_char *)m2->m_data, "-");
1425                 if (len != -1)
1426                         len -= m2->m_len;
1427                 m2 = m2->m_next;
1428         }
1429         if (len > 0)
1430                 printf("%d bytes unaccounted for.\n", len);
1431         return;
1432 }
1433
1434 u_int
1435 m_fixhdr(struct mbuf *m0)
1436 {
1437         u_int len;
1438
1439         len = m_length(m0, NULL);
1440         m0->m_pkthdr.len = len;
1441         return (len);
1442 }
1443
1444 u_int
1445 m_length(struct mbuf *m0, struct mbuf **last)
1446 {
1447         struct mbuf *m;
1448         u_int len;
1449
1450         len = 0;
1451         for (m = m0; m != NULL; m = m->m_next) {
1452                 len += m->m_len;
1453                 if (m->m_next == NULL)
1454                         break;
1455         }
1456         if (last != NULL)
1457                 *last = m;
1458         return (len);
1459 }
1460
1461 /*
1462  * Defragment a mbuf chain, returning the shortest possible
1463  * chain of mbufs and clusters.  If allocation fails and
1464  * this cannot be completed, NULL will be returned, but
1465  * the passed in chain will be unchanged.  Upon success,
1466  * the original chain will be freed, and the new chain
1467  * will be returned.
1468  *
1469  * If a non-packet header is passed in, the original
1470  * mbuf (chain?) will be returned unharmed.
1471  */
1472 struct mbuf *
1473 m_defrag(struct mbuf *m0, int how)
1474 {
1475         struct mbuf *m_new = NULL, *m_final = NULL;
1476         int progress = 0, length;
1477
1478         MBUF_CHECKSLEEP(how);
1479         if (!(m0->m_flags & M_PKTHDR))
1480                 return (m0);
1481
1482         m_fixhdr(m0); /* Needed sanity check */
1483
1484 #ifdef MBUF_STRESS_TEST
1485         if (m_defragrandomfailures) {
1486                 int temp = arc4random() & 0xff;
1487                 if (temp == 0xba)
1488                         goto nospace;
1489         }
1490 #endif
1491
1492         if (m0->m_pkthdr.len > MHLEN)
1493                 m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1494         else
1495                 m_final = m_gethdr(how, MT_DATA);
1496
1497         if (m_final == NULL)
1498                 goto nospace;
1499
1500         if (m_dup_pkthdr(m_final, m0, how) == 0)
1501                 goto nospace;
1502
1503         m_new = m_final;
1504
1505         while (progress < m0->m_pkthdr.len) {
1506                 length = m0->m_pkthdr.len - progress;
1507                 if (length > MCLBYTES)
1508                         length = MCLBYTES;
1509
1510                 if (m_new == NULL) {
1511                         if (length > MLEN)
1512                                 m_new = m_getcl(how, MT_DATA, 0);
1513                         else
1514                                 m_new = m_get(how, MT_DATA);
1515                         if (m_new == NULL)
1516                                 goto nospace;
1517                 }
1518
1519                 m_copydata(m0, progress, length, mtod(m_new, caddr_t));
1520                 progress += length;
1521                 m_new->m_len = length;
1522                 if (m_new != m_final)
1523                         m_cat(m_final, m_new);
1524                 m_new = NULL;
1525         }
1526 #ifdef MBUF_STRESS_TEST
1527         if (m0->m_next == NULL)
1528                 m_defraguseless++;
1529 #endif
1530         m_freem(m0);
1531         m0 = m_final;
1532 #ifdef MBUF_STRESS_TEST
1533         m_defragpackets++;
1534         m_defragbytes += m0->m_pkthdr.len;
1535 #endif
1536         return (m0);
1537 nospace:
1538 #ifdef MBUF_STRESS_TEST
1539         m_defragfailure++;
1540 #endif
1541         if (m_final)
1542                 m_freem(m_final);
1543         return (NULL);
1544 }
1545
1546 /*
1547  * Defragment an mbuf chain, returning at most maxfrags separate
1548  * mbufs+clusters.  If this is not possible NULL is returned and
1549  * the original mbuf chain is left in it's present (potentially
1550  * modified) state.  We use two techniques: collapsing consecutive
1551  * mbufs and replacing consecutive mbufs by a cluster.
1552  *
1553  * NB: this should really be named m_defrag but that name is taken
1554  */
1555 struct mbuf *
1556 m_collapse(struct mbuf *m0, int how, int maxfrags)
1557 {
1558         struct mbuf *m, *n, *n2, **prev;
1559         u_int curfrags;
1560
1561         /*
1562          * Calculate the current number of frags.
1563          */
1564         curfrags = 0;
1565         for (m = m0; m != NULL; m = m->m_next)
1566                 curfrags++;
1567         /*
1568          * First, try to collapse mbufs.  Note that we always collapse
1569          * towards the front so we don't need to deal with moving the
1570          * pkthdr.  This may be suboptimal if the first mbuf has much
1571          * less data than the following.
1572          */
1573         m = m0;
1574 again:
1575         for (;;) {
1576                 n = m->m_next;
1577                 if (n == NULL)
1578                         break;
1579                 if ((m->m_flags & M_RDONLY) == 0 &&
1580                     n->m_len < M_TRAILINGSPACE(m)) {
1581                         bcopy(mtod(n, void *), mtod(m, char *) + m->m_len,
1582                                 n->m_len);
1583                         m->m_len += n->m_len;
1584                         m->m_next = n->m_next;
1585                         m_free(n);
1586                         if (--curfrags <= maxfrags)
1587                                 return m0;
1588                 } else
1589                         m = n;
1590         }
1591         KASSERT(maxfrags > 1,
1592                 ("maxfrags %u, but normal collapse failed", maxfrags));
1593         /*
1594          * Collapse consecutive mbufs to a cluster.
1595          */
1596         prev = &m0->m_next;             /* NB: not the first mbuf */
1597         while ((n = *prev) != NULL) {
1598                 if ((n2 = n->m_next) != NULL &&
1599                     n->m_len + n2->m_len < MCLBYTES) {
1600                         m = m_getcl(how, MT_DATA, 0);
1601                         if (m == NULL)
1602                                 goto bad;
1603                         bcopy(mtod(n, void *), mtod(m, void *), n->m_len);
1604                         bcopy(mtod(n2, void *), mtod(m, char *) + n->m_len,
1605                                 n2->m_len);
1606                         m->m_len = n->m_len + n2->m_len;
1607                         m->m_next = n2->m_next;
1608                         *prev = m;
1609                         m_free(n);
1610                         m_free(n2);
1611                         if (--curfrags <= maxfrags)     /* +1 cl -2 mbufs */
1612                                 return m0;
1613                         /*
1614                          * Still not there, try the normal collapse
1615                          * again before we allocate another cluster.
1616                          */
1617                         goto again;
1618                 }
1619                 prev = &n->m_next;
1620         }
1621         /*
1622          * No place where we can collapse to a cluster; punt.
1623          * This can occur if, for example, you request 2 frags
1624          * but the packet requires that both be clusters (we
1625          * never reallocate the first mbuf to avoid moving the
1626          * packet header).
1627          */
1628 bad:
1629         return NULL;
1630 }
1631
1632 #ifdef MBUF_STRESS_TEST
1633
1634 /*
1635  * Fragment an mbuf chain.  There's no reason you'd ever want to do
1636  * this in normal usage, but it's great for stress testing various
1637  * mbuf consumers.
1638  *
1639  * If fragmentation is not possible, the original chain will be
1640  * returned.
1641  *
1642  * Possible length values:
1643  * 0     no fragmentation will occur
1644  * > 0  each fragment will be of the specified length
1645  * -1   each fragment will be the same random value in length
1646  * -2   each fragment's length will be entirely random
1647  * (Random values range from 1 to 256)
1648  */
1649 struct mbuf *
1650 m_fragment(struct mbuf *m0, int how, int length)
1651 {
1652         struct mbuf *m_new = NULL, *m_final = NULL;
1653         int progress = 0;
1654
1655         if (!(m0->m_flags & M_PKTHDR))
1656                 return (m0);
1657
1658         if ((length == 0) || (length < -2))
1659                 return (m0);
1660
1661         m_fixhdr(m0); /* Needed sanity check */
1662
1663         m_final = m_getcl(how, MT_DATA, M_PKTHDR);
1664
1665         if (m_final == NULL)
1666                 goto nospace;
1667
1668         if (m_dup_pkthdr(m_final, m0, how) == 0)
1669                 goto nospace;
1670
1671         m_new = m_final;
1672
1673         if (length == -1)
1674                 length = 1 + (arc4random() & 255);
1675
1676         while (progress < m0->m_pkthdr.len) {
1677                 int fraglen;
1678
1679                 if (length > 0)
1680                         fraglen = length;
1681                 else
1682                         fraglen = 1 + (arc4random() & 255);
1683                 if (fraglen > m0->m_pkthdr.len - progress)
1684                         fraglen = m0->m_pkthdr.len - progress;
1685
1686                 if (fraglen > MCLBYTES)
1687                         fraglen = MCLBYTES;
1688
1689                 if (m_new == NULL) {
1690                         m_new = m_getcl(how, MT_DATA, 0);
1691                         if (m_new == NULL)
1692                                 goto nospace;
1693                 }
1694
1695                 m_copydata(m0, progress, fraglen, mtod(m_new, caddr_t));
1696                 progress += fraglen;
1697                 m_new->m_len = fraglen;
1698                 if (m_new != m_final)
1699                         m_cat(m_final, m_new);
1700                 m_new = NULL;
1701         }
1702         m_freem(m0);
1703         m0 = m_final;
1704         return (m0);
1705 nospace:
1706         if (m_final)
1707                 m_freem(m_final);
1708         /* Return the original chain on failure */
1709         return (m0);
1710 }
1711
1712 #endif
1713
1714 /*
1715  * Copy the contents of uio into a properly sized mbuf chain.
1716  */
1717 struct mbuf *
1718 m_uiotombuf(struct uio *uio, int how, int len, int align, int flags)
1719 {
1720         struct mbuf *m, *mb;
1721         int error, length, total;
1722         int progress = 0;
1723
1724         /*
1725          * len can be zero or an arbitrary large value bound by
1726          * the total data supplied by the uio.
1727          */
1728         if (len > 0)
1729                 total = min(uio->uio_resid, len);
1730         else
1731                 total = uio->uio_resid;
1732
1733         /*
1734          * The smallest unit returned by m_getm2() is a single mbuf
1735          * with pkthdr.  We can't align past it.
1736          */
1737         if (align >= MHLEN)
1738                 return (NULL);
1739
1740         /*
1741          * Give us the full allocation or nothing.
1742          * If len is zero return the smallest empty mbuf.
1743          */
1744         m = m_getm2(NULL, max(total + align, 1), how, MT_DATA, flags);
1745         if (m == NULL)
1746                 return (NULL);
1747         m->m_data += align;
1748
1749         /* Fill all mbufs with uio data and update header information. */
1750         for (mb = m; mb != NULL; mb = mb->m_next) {
1751                 length = min(M_TRAILINGSPACE(mb), total - progress);
1752
1753                 error = uiomove(mtod(mb, void *), length, uio);
1754                 if (error) {
1755                         m_freem(m);
1756                         return (NULL);
1757                 }
1758
1759                 mb->m_len = length;
1760                 progress += length;
1761                 if (flags & M_PKTHDR)
1762                         m->m_pkthdr.len += length;
1763         }
1764         KASSERT(progress == total, ("%s: progress != total", __func__));
1765
1766         return (m);
1767 }
1768
1769 /*
1770  * Set the m_data pointer of a newly-allocated mbuf
1771  * to place an object of the specified size at the
1772  * end of the mbuf, longword aligned.
1773  */
1774 void
1775 m_align(struct mbuf *m, int len)
1776 {
1777         int adjust;
1778
1779         if (m->m_flags & M_EXT)
1780                 adjust = m->m_ext.ext_size - len;
1781         else if (m->m_flags & M_PKTHDR)
1782                 adjust = MHLEN - len;
1783         else
1784                 adjust = MLEN - len;
1785         m->m_data += adjust &~ (sizeof(long)-1);
1786 }
1787
1788 /*
1789  * Create a writable copy of the mbuf chain.  While doing this
1790  * we compact the chain with a goal of producing a chain with
1791  * at most two mbufs.  The second mbuf in this chain is likely
1792  * to be a cluster.  The primary purpose of this work is to create
1793  * a writable packet for encryption, compression, etc.  The
1794  * secondary goal is to linearize the data so the data can be
1795  * passed to crypto hardware in the most efficient manner possible.
1796  */
1797 struct mbuf *
1798 m_unshare(struct mbuf *m0, int how)
1799 {
1800         struct mbuf *m, *mprev;
1801         struct mbuf *n, *mfirst, *mlast;
1802         int len, off;
1803
1804         mprev = NULL;
1805         for (m = m0; m != NULL; m = mprev->m_next) {
1806                 /*
1807                  * Regular mbufs are ignored unless there's a cluster
1808                  * in front of it that we can use to coalesce.  We do
1809                  * the latter mainly so later clusters can be coalesced
1810                  * also w/o having to handle them specially (i.e. convert
1811                  * mbuf+cluster -> cluster).  This optimization is heavily
1812                  * influenced by the assumption that we're running over
1813                  * Ethernet where MCLBYTES is large enough that the max
1814                  * packet size will permit lots of coalescing into a
1815                  * single cluster.  This in turn permits efficient
1816                  * crypto operations, especially when using hardware.
1817                  */
1818                 if ((m->m_flags & M_EXT) == 0) {
1819                         if (mprev && (mprev->m_flags & M_EXT) &&
1820                             m->m_len <= M_TRAILINGSPACE(mprev)) {
1821                                 /* XXX: this ignores mbuf types */
1822                                 memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1823                                        mtod(m, caddr_t), m->m_len);
1824                                 mprev->m_len += m->m_len;
1825                                 mprev->m_next = m->m_next;      /* unlink from chain */
1826                                 m_free(m);                      /* reclaim mbuf */
1827 #if 0
1828                                 newipsecstat.ips_mbcoalesced++;
1829 #endif
1830                         } else {
1831                                 mprev = m;
1832                         }
1833                         continue;
1834                 }
1835                 /*
1836                  * Writable mbufs are left alone (for now).
1837                  */
1838                 if (M_WRITABLE(m)) {
1839                         mprev = m;
1840                         continue;
1841                 }
1842
1843                 /*
1844                  * Not writable, replace with a copy or coalesce with
1845                  * the previous mbuf if possible (since we have to copy
1846                  * it anyway, we try to reduce the number of mbufs and
1847                  * clusters so that future work is easier).
1848                  */
1849                 KASSERT(m->m_flags & M_EXT, ("m_flags 0x%x", m->m_flags));
1850                 /* NB: we only coalesce into a cluster or larger */
1851                 if (mprev != NULL && (mprev->m_flags & M_EXT) &&
1852                     m->m_len <= M_TRAILINGSPACE(mprev)) {
1853                         /* XXX: this ignores mbuf types */
1854                         memcpy(mtod(mprev, caddr_t) + mprev->m_len,
1855                                mtod(m, caddr_t), m->m_len);
1856                         mprev->m_len += m->m_len;
1857                         mprev->m_next = m->m_next;      /* unlink from chain */
1858                         m_free(m);                      /* reclaim mbuf */
1859 #if 0
1860                         newipsecstat.ips_clcoalesced++;
1861 #endif
1862                         continue;
1863                 }
1864
1865                 /*
1866                  * Allocate new space to hold the copy...
1867                  */
1868                 /* XXX why can M_PKTHDR be set past the first mbuf? */
1869                 if (mprev == NULL && (m->m_flags & M_PKTHDR)) {
1870                         /*
1871                          * NB: if a packet header is present we must
1872                          * allocate the mbuf separately from any cluster
1873                          * because M_MOVE_PKTHDR will smash the data
1874                          * pointer and drop the M_EXT marker.
1875                          */
1876                         MGETHDR(n, how, m->m_type);
1877                         if (n == NULL) {
1878                                 m_freem(m0);
1879                                 return (NULL);
1880                         }
1881                         M_MOVE_PKTHDR(n, m);
1882                         MCLGET(n, how);
1883                         if ((n->m_flags & M_EXT) == 0) {
1884                                 m_free(n);
1885                                 m_freem(m0);
1886                                 return (NULL);
1887                         }
1888                 } else {
1889                         n = m_getcl(how, m->m_type, m->m_flags);
1890                         if (n == NULL) {
1891                                 m_freem(m0);
1892                                 return (NULL);
1893                         }
1894                 }
1895                 /*
1896                  * ... and copy the data.  We deal with jumbo mbufs
1897                  * (i.e. m_len > MCLBYTES) by splitting them into
1898                  * clusters.  We could just malloc a buffer and make
1899                  * it external but too many device drivers don't know
1900                  * how to break up the non-contiguous memory when
1901                  * doing DMA.
1902                  */
1903                 len = m->m_len;
1904                 off = 0;
1905                 mfirst = n;
1906                 mlast = NULL;
1907                 for (;;) {
1908                         int cc = min(len, MCLBYTES);
1909                         memcpy(mtod(n, caddr_t), mtod(m, caddr_t) + off, cc);
1910                         n->m_len = cc;
1911                         if (mlast != NULL)
1912                                 mlast->m_next = n;
1913                         mlast = n;
1914 #if 0
1915                         newipsecstat.ips_clcopied++;
1916 #endif
1917
1918                         len -= cc;
1919                         if (len <= 0)
1920                                 break;
1921                         off += cc;
1922
1923                         n = m_getcl(how, m->m_type, m->m_flags);
1924                         if (n == NULL) {
1925                                 m_freem(mfirst);
1926                                 m_freem(m0);
1927                                 return (NULL);
1928                         }
1929                 }
1930                 n->m_next = m->m_next;
1931                 if (mprev == NULL)
1932                         m0 = mfirst;            /* new head of chain */
1933                 else
1934                         mprev->m_next = mfirst; /* replace old mbuf */
1935                 m_free(m);                      /* release old mbuf */
1936                 mprev = mfirst;
1937         }
1938         return (m0);
1939 }
1940
1941 #ifdef MBUF_PROFILING
1942
1943 #define MP_BUCKETS 32 /* don't just change this as things may overflow.*/
1944 struct mbufprofile {
1945         uintmax_t wasted[MP_BUCKETS];
1946         uintmax_t used[MP_BUCKETS];
1947         uintmax_t segments[MP_BUCKETS];
1948 } mbprof;
1949
1950 #define MP_MAXDIGITS 21 /* strlen("16,000,000,000,000,000,000") == 21 */
1951 #define MP_NUMLINES 6
1952 #define MP_NUMSPERLINE 16
1953 #define MP_EXTRABYTES 64        /* > strlen("used:\nwasted:\nsegments:\n") */
1954 /* work out max space needed and add a bit of spare space too */
1955 #define MP_MAXLINE ((MP_MAXDIGITS+1) * MP_NUMSPERLINE)
1956 #define MP_BUFSIZE ((MP_MAXLINE * MP_NUMLINES) + 1 + MP_EXTRABYTES)
1957
1958 char mbprofbuf[MP_BUFSIZE];
1959
1960 void
1961 m_profile(struct mbuf *m)
1962 {
1963         int segments = 0;
1964         int used = 0;
1965         int wasted = 0;
1966
1967         while (m) {
1968                 segments++;
1969                 used += m->m_len;
1970                 if (m->m_flags & M_EXT) {
1971                         wasted += MHLEN - sizeof(m->m_ext) +
1972                             m->m_ext.ext_size - m->m_len;
1973                 } else {
1974                         if (m->m_flags & M_PKTHDR)
1975                                 wasted += MHLEN - m->m_len;
1976                         else
1977                                 wasted += MLEN - m->m_len;
1978                 }
1979                 m = m->m_next;
1980         }
1981         /* be paranoid.. it helps */
1982         if (segments > MP_BUCKETS - 1)
1983                 segments = MP_BUCKETS - 1;
1984         if (used > 100000)
1985                 used = 100000;
1986         if (wasted > 100000)
1987                 wasted = 100000;
1988         /* store in the appropriate bucket */
1989         /* don't bother locking. if it's slightly off, so what? */
1990         mbprof.segments[segments]++;
1991         mbprof.used[fls(used)]++;
1992         mbprof.wasted[fls(wasted)]++;
1993 }
1994
1995 static void
1996 mbprof_textify(void)
1997 {
1998         int offset;
1999         char *c;
2000         u_int64_t *p;
2001
2002
2003         p = &mbprof.wasted[0];
2004         c = mbprofbuf;
2005         offset = snprintf(c, MP_MAXLINE + 10,
2006             "wasted:\n"
2007             "%ju %ju %ju %ju %ju %ju %ju %ju "
2008             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2009             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2010             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2011 #ifdef BIG_ARRAY
2012         p = &mbprof.wasted[16];
2013         c += offset;
2014         offset = snprintf(c, MP_MAXLINE,
2015             "%ju %ju %ju %ju %ju %ju %ju %ju "
2016             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2017             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2018             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2019 #endif
2020         p = &mbprof.used[0];
2021         c += offset;
2022         offset = snprintf(c, MP_MAXLINE + 10,
2023             "used:\n"
2024             "%ju %ju %ju %ju %ju %ju %ju %ju "
2025             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2026             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2027             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2028 #ifdef BIG_ARRAY
2029         p = &mbprof.used[16];
2030         c += offset;
2031         offset = snprintf(c, MP_MAXLINE,
2032             "%ju %ju %ju %ju %ju %ju %ju %ju "
2033             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2034             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2035             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2036 #endif
2037         p = &mbprof.segments[0];
2038         c += offset;
2039         offset = snprintf(c, MP_MAXLINE + 10,
2040             "segments:\n"
2041             "%ju %ju %ju %ju %ju %ju %ju %ju "
2042             "%ju %ju %ju %ju %ju %ju %ju %ju\n",
2043             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2044             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2045 #ifdef BIG_ARRAY
2046         p = &mbprof.segments[16];
2047         c += offset;
2048         offset = snprintf(c, MP_MAXLINE,
2049             "%ju %ju %ju %ju %ju %ju %ju %ju "
2050             "%ju %ju %ju %ju %ju %ju %ju %jju",
2051             p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7],
2052             p[8], p[9], p[10], p[11], p[12], p[13], p[14], p[15]);
2053 #endif
2054 }
2055
2056 static int
2057 mbprof_handler(SYSCTL_HANDLER_ARGS)
2058 {
2059         int error;
2060
2061         mbprof_textify();
2062         error = SYSCTL_OUT(req, mbprofbuf, strlen(mbprofbuf) + 1);
2063         return (error);
2064 }
2065
2066 static int
2067 mbprof_clr_handler(SYSCTL_HANDLER_ARGS)
2068 {
2069         int clear, error;
2070
2071         clear = 0;
2072         error = sysctl_handle_int(oidp, &clear, 0, req);
2073         if (error || !req->newptr)
2074                 return (error);
2075
2076         if (clear) {
2077                 bzero(&mbprof, sizeof(mbprof));
2078         }
2079
2080         return (error);
2081 }
2082
2083
2084 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofile, CTLTYPE_STRING|CTLFLAG_RD,
2085             NULL, 0, mbprof_handler, "A", "mbuf profiling statistics");
2086
2087 SYSCTL_PROC(_kern_ipc, OID_AUTO, mbufprofileclr, CTLTYPE_INT|CTLFLAG_RW,
2088             NULL, 0, mbprof_clr_handler, "I", "clear mbuf profiling statistics");
2089 #endif
2090