bsd/kern/uipc_mbuf2.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*      $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $   */
  23
  24 /*
  25  * Copyright (C) 1999 WIDE Project.
  26  * All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. Neither the name of the project nor the names of its contributors
  37  *    may be used to endorse or promote products derived from this software
  38  *    without specific prior written permission.
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  50  * SUCH DAMAGE.
  51  */
  52
  53 /*
  54  * Copyright (c) 1982, 1986, 1988, 1991, 1993
  55  *      The Regents of the University of California.  All rights reserved.
  56  *
  57  * Redistribution and use in source and binary forms, with or without
  58  * modification, are permitted provided that the following conditions
  59  * are met:
  60  * 1. Redistributions of source code must retain the above copyright
  61  *    notice, this list of conditions and the following disclaimer.
  62  * 2. Redistributions in binary form must reproduce the above copyright
  63  *    notice, this list of conditions and the following disclaimer in the
  64  *    documentation and/or other materials provided with the distribution.
  65  * 3. All advertising materials mentioning features or use of this software
  66  *    must display the following acknowledgement:
  67  *      This product includes software developed by the University of
  68  *      California, Berkeley and its contributors.
  69  * 4. Neither the name of the University nor the names of its contributors
  70  *    may be used to endorse or promote products derived from this software
  71  *    without specific prior written permission.
  72  *
  73  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  74  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  75  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  76  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  77  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  78  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  79  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  80  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  81  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  82  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  83  * SUCH DAMAGE.
  84  *
  85  *      @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95
  86  */
  87
  88 #define PULLDOWN_STAT
  89 /*#define PULLDOWN_DEBUG*/
  90
  91 #ifdef PULLDOWN_STAT
  92 #if defined(__NetBSD__) || (defined(__FreeBSD__) && __FreeBSD__ >= 3)
  93 #include "opt_inet.h"
  94 #endif
  95 #endif
  96
  97 #include <sys/param.h>
  98 #include <sys/systm.h>
  99 #include <sys/proc.h>
 100 #include <sys/malloc.h>
 101 #include <sys/mbuf.h>
 102 #if defined(PULLDOWN_STAT) && defined(INET6)
 103 #include <netinet/in.h>
 104 #include <netinet/ip6.h>
 105 #include <netinet6/ip6_var.h>
 106 #endif
 107
 108 /*
 109  * ensure that [off, off + len) is contiguous on the mbuf chain "m".
 110  * packet chain before "off" is kept untouched.
 111  * if offp == NULL, the target will start at <retval, 0> on resulting chain.
 112  * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
 113  *
 114  * on error return (NULL return value), original "m" will be freed.
 115  *
 116  * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)
 117  */
 118 struct mbuf *
 119 m_pulldown(m, off, len, offp)
 120         struct mbuf *m;
 121         int off, len;
 122         int *offp;
 123 {
 124         struct mbuf *n, *o;
 125         int hlen, tlen, olen;
 126         int sharedcluster;
 127 #if defined(PULLDOWN_STAT) && defined(INET6)
 128         static struct mbuf *prev = NULL;
 129         int prevlen = 0, prevmlen = 0;
 130 #endif
 131
 132         /* check invalid arguments. */
 133         if (m == NULL)
 134                 panic("m == NULL in m_pulldown()");
 135         if (len > MCLBYTES) {
 136                 m_freem(m);
 137                 return NULL;    /* impossible */
 138         }
 139
 140 #if defined(PULLDOWN_STAT) && defined(INET6)
 141         ip6stat.ip6s_pulldown++;
 142 #endif
 143
 144 #if defined(PULLDOWN_STAT) && defined(INET6)
 145         /* statistics for m_pullup */
 146         ip6stat.ip6s_pullup++;
 147         if (off + len > MHLEN)
 148                 ip6stat.ip6s_pullup_fail++;
 149         else {
 150                 int dlen, mlen;
 151
 152                 dlen = (prev == m) ? prevlen : m->m_len;
 153                 mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);
 154
 155                 if (dlen >= off + len)
 156                         ip6stat.ip6s_pullup--; /* call will not be made! */
 157                 else if ((m->m_flags & M_EXT) != 0) {
 158                         ip6stat.ip6s_pullup_alloc++;
 159                         ip6stat.ip6s_pullup_copy++;
 160                 } else {
 161                         if (mlen >= off + len)
 162                                 ip6stat.ip6s_pullup_copy++;
 163                         else {
 164                                 ip6stat.ip6s_pullup_alloc++;
 165                                 ip6stat.ip6s_pullup_copy++;
 166                         }
 167                 }
 168
 169                 prevlen = off + len;
 170                 prevmlen = MHLEN;
 171         }
 172
 173         /* statistics for m_pullup2 */
 174         ip6stat.ip6s_pullup2++;
 175         if (off + len > MCLBYTES)
 176                 ip6stat.ip6s_pullup2_fail++;
 177         else {
 178                 int dlen, mlen;
 179
 180                 dlen = (prev == m) ? prevlen : m->m_len;
 181                 mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);
 182                 prevlen = off + len;
 183                 prevmlen = mlen;
 184
 185                 if (dlen >= off + len)
 186                         ip6stat.ip6s_pullup2--; /* call will not be made! */
 187                 else if ((m->m_flags & M_EXT) != 0) {
 188                         ip6stat.ip6s_pullup2_alloc++;
 189                         ip6stat.ip6s_pullup2_copy++;
 190                         prevmlen = (off + len > MHLEN) ? MCLBYTES : MHLEN;
 191                 } else {
 192                         if (mlen >= off + len)
 193                                 ip6stat.ip6s_pullup2_copy++;
 194                         else {
 195                                 ip6stat.ip6s_pullup2_alloc++;
 196                                 ip6stat.ip6s_pullup2_copy++;
 197                                 prevmlen = (off + len > MHLEN) ? MCLBYTES
 198                                                                : MHLEN;
 199                         }
 200                 }
 201         }
 202
 203         prev = m;
 204 #endif
 205
 206 #ifdef PULLDOWN_DEBUG
 207     {
 208         struct mbuf *t;
 209         printf("before:");
 210         for (t = m; t; t = t->m_next)
 211                 printf(" %d", t->m_len);
 212         printf("\n");
 213     }
 214 #endif
 215         n = m;
 216         while (n != NULL && off > 0) {
 217                 if (n->m_len > off)
 218                         break;
 219                 off -= n->m_len;
 220                 n = n->m_next;
 221         }
 222         /* be sure to point non-empty mbuf */
 223         while (n != NULL && n->m_len == 0)
 224                 n = n->m_next;
 225         if (!n) {
 226                 m_freem(m);
 227                 return NULL;    /* mbuf chain too short */
 228         }
 229
 230         /*
 231          * the target data is on <n, off>.
 232          * if we got enough data on the mbuf "n", we're done.
 233          */
 234         if ((off == 0 || offp) && len <= n->m_len - off)
 235                 goto ok;
 236
 237 #if defined(PULLDOWN_STAT) && defined(INET6)
 238         ip6stat.ip6s_pulldown_copy++;
 239 #endif
 240
 241         /*
 242          * when len < n->m_len - off and off != 0, it is a special case.
 243          * len bytes from <n, off> sits in single mbuf, but the caller does
 244          * not like the starting position (off).
 245          * chop the current mbuf into two pieces, set off to 0.
 246          */
 247         if (len < n->m_len - off) {
 248                 o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
 249                 if (o == NULL) {
 250                         m_freem(m);
 251                         return NULL;    /* ENOBUFS */
 252                 }
 253                 n->m_len = off;
 254                 o->m_next = n->m_next;
 255                 n->m_next = o;
 256                 n = n->m_next;
 257                 off = 0;
 258                 goto ok;
 259         }
 260
 261         /*
 262          * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
 263          * and construct contiguous mbuf with m_len == len.
 264          * note that hlen + tlen == len, and tlen > 0.
 265          */
 266         hlen = n->m_len - off;
 267         tlen = len - hlen;
 268
 269         /*
 270          * ensure that we have enough trailing data on mbuf chain.
 271          * if not, we can do nothing about the chain.
 272          */
 273         olen = 0;
 274         for (o = n->m_next; o != NULL; o = o->m_next)
 275                 olen += o->m_len;
 276         if (hlen + olen < len) {
 277                 m_freem(m);
 278                 return NULL;    /* mbuf chain too short */
 279         }
 280
 281         /*
 282          * easy cases first.
 283          * we need to use m_copydata() to get data from <n->m_next, 0>.
 284          */
 285         if ((n->m_flags & M_EXT) == 0)
 286                 sharedcluster = 0;
 287         else {
 288 #ifdef __bsdi__
 289                 if (n->m_ext.ext_func)
 290 #else
 291                 if (n->m_ext.ext_free)
 292 #endif
 293                         sharedcluster = 1;
 294 #ifdef __NetBSD__
 295                 else if (MCLISREFERENCED(n))
 296 #else
 297                 else if (mclrefcnt[mtocl(n->m_ext.ext_buf)] > 1)
 298 #endif
 299                         sharedcluster = 1;
 300                 else
 301                         sharedcluster = 0;
 302         }
 303         if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
 304          && !sharedcluster) {
 305                 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
 306                 n->m_len += tlen;
 307                 m_adj(n->m_next, tlen);
 308                 goto ok;
 309         }
 310         if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
 311          && !sharedcluster) {
 312                 n->m_next->m_data -= hlen;
 313                 n->m_next->m_len += hlen;
 314                 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
 315                 n->m_len -= hlen;
 316                 n = n->m_next;
 317                 off = 0;
 318                 goto ok;
 319         }
 320
 321         /*
 322          * now, we need to do the hard way.  don't m_copy as there's no room
 323          * on both end.
 324          */
 325 #if defined(PULLDOWN_STAT) && defined(INET6)
 326         ip6stat.ip6s_pulldown_alloc++;
 327 #endif
 328         MGET(o, M_DONTWAIT, m->m_type);
 329         if (o == NULL) {
 330                 m_freem(m);
 331                 return NULL;    /* ENOBUFS */
 332         }
 333         if (len > MHLEN) {      /* use MHLEN just for safety */
 334                 MCLGET(o, M_DONTWAIT);
 335                 if ((o->m_flags & M_EXT) == 0) {
 336                         m_freem(m);
 337                         m_free(o);
 338                         return NULL;    /* ENOBUFS */
 339                 }
 340         }
 341         /* get hlen from <n, off> into <o, 0> */
 342         o->m_len = hlen;
 343         bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
 344         n->m_len -= hlen;
 345         /* get tlen from <n->m_next, 0> into <o, hlen> */
 346         m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
 347         o->m_len += tlen;
 348         m_adj(n->m_next, tlen);
 349         o->m_next = n->m_next;
 350         n->m_next = o;
 351         n = o;
 352         off = 0;
 353
 354 ok:
 355 #ifdef PULLDOWN_DEBUG
 356     {
 357         struct mbuf *t;
 358         printf("after:");
 359         for (t = m; t; t = t->m_next)
 360                 printf("%c%d", t == n ? '*' : ' ', t->m_len);
 361         printf(" (off=%d)\n", off);
 362     }
 363 #endif
 364         if (offp)
 365                 *offp = off;
 366         return n;
 367 }
 368
 369 /*
 370  * pkthdr.aux chain manipulation.
 371  * we don't allow clusters at this moment.
 372  */
 373 struct mbuf *
 374 m_aux_add(m, af, type)
 375         struct mbuf *m;
 376         int af, type;
 377 {
 378         struct mbuf *n;
 379         struct mauxtag *t;
 380
 381         if ((m->m_flags & M_PKTHDR) == 0)
 382                 return NULL;
 383
 384         n = m_aux_find(m, af, type);
 385         if (n)
 386                 return n;
 387
 388         MGET(n, M_WAIT, m->m_type);
 389         if (n == NULL)
 390                 return NULL;
 391
 392         t = mtod(n, struct mauxtag *);
 393         t->af = af;
 394         t->type = type;
 395         n->m_data += sizeof(struct mauxtag);
 396         n->m_len = 0;
 397         n->m_next = m->m_pkthdr.aux;
 398         m->m_pkthdr.aux = n;
 399         return n;
 400 }
 401
 402 struct mbuf *
 403 m_aux_find(m, af, type)
 404         struct mbuf *m;
 405         int af, type;
 406 {
 407         struct mbuf *n;
 408         struct mauxtag *t;
 409
 410         if ((m->m_flags & M_PKTHDR) == 0)
 411                 return NULL;
 412
 413         for (n = m->m_pkthdr.aux; n; n = n->m_next) {
 414                 t = (struct mauxtag *)n->m_dat;
 415                 if (t->af == af && t->type == type)
 416                         return n;
 417         }
 418         return NULL;
 419 }
 420
 421 void
 422 m_aux_delete(m, victim)
 423         struct mbuf *m;
 424         struct mbuf *victim;
 425 {
 426         struct mbuf *n, *prev, *next;
 427         struct mauxtag *t;
 428
 429         if ((m->m_flags & M_PKTHDR) == 0)
 430                 return;
 431
 432         prev = NULL;
 433         n = m->m_pkthdr.aux;
 434         while (n) {
 435                 t = (struct mauxtag *)n->m_dat;
 436                 next = n->m_next;
 437                 if (n == victim) {
 438                         if (prev)
 439                                 prev->m_next = n->m_next;
 440                         else
 441                                 m->m_pkthdr.aux = n->m_next;
 442                         n->m_next = NULL;
 443                         m_free(n);
 444                 } else
 445                         prev = n;
 446                 n = next;
 447         }
 448 }