bsd/kern/uipc_mbuf2.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*      $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $   */
  26
  27 /*
  28  * Copyright (C) 1999 WIDE Project.
  29  * All rights reserved.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  * 1. Redistributions of source code must retain the above copyright
  35  *    notice, this list of conditions and the following disclaimer.
  36  * 2. Redistributions in binary form must reproduce the above copyright
  37  *    notice, this list of conditions and the following disclaimer in the
  38  *    documentation and/or other materials provided with the distribution.
  39  * 3. Neither the name of the project nor the names of its contributors
  40  *    may be used to endorse or promote products derived from this software
  41  *    without specific prior written permission.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  */
  55
  56 /*
  57  * Copyright (c) 1982, 1986, 1988, 1991, 1993
  58  *      The Regents of the University of California.  All rights reserved.
  59  *
  60  * Redistribution and use in source and binary forms, with or without
  61  * modification, are permitted provided that the following conditions
  62  * are met:
  63  * 1. Redistributions of source code must retain the above copyright
  64  *    notice, this list of conditions and the following disclaimer.
  65  * 2. Redistributions in binary form must reproduce the above copyright
  66  *    notice, this list of conditions and the following disclaimer in the
  67  *    documentation and/or other materials provided with the distribution.
  68  * 3. All advertising materials mentioning features or use of this software
  69  *    must display the following acknowledgement:
  70  *      This product includes software developed by the University of
  71  *      California, Berkeley and its contributors.
  72  * 4. Neither the name of the University nor the names of its contributors
  73  *    may be used to endorse or promote products derived from this software
  74  *    without specific prior written permission.
  75  *
  76  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  77  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  78  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  79  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  80  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  81  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  82  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  83  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  84  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  85  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  86  * SUCH DAMAGE.
  87  *
  88  *      @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95
  89  */
  90
  91
  92 /*#define PULLDOWN_DEBUG*/
  93
  94 #include <sys/param.h>
  95 #include <sys/systm.h>
  96 #include <sys/proc.h>
  97 #include <sys/malloc.h>
  98 #include <sys/mbuf.h>
  99 #if defined(PULLDOWN_STAT) && defined(INET6)
 100 #include <netinet/in.h>
 101 #include <netinet/ip6.h>
 102 #include <netinet6/ip6_var.h>
 103 #endif
 104
 105 /*
 106  * ensure that [off, off + len) is contiguous on the mbuf chain "m".
 107  * packet chain before "off" is kept untouched.
 108  * if offp == NULL, the target will start at <retval, 0> on resulting chain.
 109  * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
 110  *
 111  * on error return (NULL return value), original "m" will be freed.
 112  *
 113  * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)
 114  */
 115 struct mbuf *
 116 m_pulldown(m, off, len, offp)
 117         struct mbuf *m;
 118         int off, len;
 119         int *offp;
 120 {
 121         struct mbuf *n, *o;
 122         int hlen, tlen, olen;
 123         int sharedcluster;
 124 #if defined(PULLDOWN_STAT) && defined(INET6)
 125         static struct mbuf *prev = NULL;
 126         int prevlen = 0, prevmlen = 0;
 127 #endif
 128
 129         /* check invalid arguments. */
 130         if (m == NULL)
 131                 panic("m == NULL in m_pulldown()");
 132         if (len > MCLBYTES) {
 133                 m_freem(m);
 134                 return NULL;    /* impossible */
 135         }
 136
 137 #if defined(PULLDOWN_STAT) && defined(INET6)
 138         ip6stat.ip6s_pulldown++;
 139 #endif
 140
 141 #if defined(PULLDOWN_STAT) && defined(INET6)
 142         /* statistics for m_pullup */
 143         ip6stat.ip6s_pullup++;
 144         if (off + len > MHLEN)
 145                 ip6stat.ip6s_pullup_fail++;
 146         else {
 147                 int dlen, mlen;
 148
 149                 dlen = (prev == m) ? prevlen : m->m_len;
 150                 mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);
 151
 152                 if (dlen >= off + len)
 153                         ip6stat.ip6s_pullup--; /* call will not be made! */
 154                 else if ((m->m_flags & M_EXT) != 0) {
 155                         ip6stat.ip6s_pullup_alloc++;
 156                         ip6stat.ip6s_pullup_copy++;
 157                 } else {
 158                         if (mlen >= off + len)
 159                                 ip6stat.ip6s_pullup_copy++;
 160                         else {
 161                                 ip6stat.ip6s_pullup_alloc++;
 162                                 ip6stat.ip6s_pullup_copy++;
 163                         }
 164                 }
 165
 166                 prevlen = off + len;
 167                 prevmlen = MHLEN;
 168         }
 169
 170         /* statistics for m_pullup2 */
 171         ip6stat.ip6s_pullup2++;
 172         if (off + len > MCLBYTES)
 173                 ip6stat.ip6s_pullup2_fail++;
 174         else {
 175                 int dlen, mlen;
 176
 177                 dlen = (prev == m) ? prevlen : m->m_len;
 178                 mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);
 179                 prevlen = off + len;
 180                 prevmlen = mlen;
 181
 182                 if (dlen >= off + len)
 183                         ip6stat.ip6s_pullup2--; /* call will not be made! */
 184                 else if ((m->m_flags & M_EXT) != 0) {
 185                         ip6stat.ip6s_pullup2_alloc++;
 186                         ip6stat.ip6s_pullup2_copy++;
 187                         prevmlen = (off + len > MHLEN) ? MCLBYTES : MHLEN;
 188                 } else {
 189                         if (mlen >= off + len)
 190                                 ip6stat.ip6s_pullup2_copy++;
 191                         else {
 192                                 ip6stat.ip6s_pullup2_alloc++;
 193                                 ip6stat.ip6s_pullup2_copy++;
 194                                 prevmlen = (off + len > MHLEN) ? MCLBYTES
 195                                                                : MHLEN;
 196                         }
 197                 }
 198         }
 199
 200         prev = m;
 201 #endif
 202
 203 #ifdef PULLDOWN_DEBUG
 204     {
 205         struct mbuf *t;
 206         printf("before:");
 207         for (t = m; t; t = t->m_next)
 208                 printf(" %d", t->m_len);
 209         printf("\n");
 210     }
 211 #endif
 212         n = m;
 213         while (n != NULL && off > 0) {
 214                 if (n->m_len > off)
 215                         break;
 216                 off -= n->m_len;
 217                 n = n->m_next;
 218         }
 219         /* be sure to point non-empty mbuf */
 220         while (n != NULL && n->m_len == 0)
 221                 n = n->m_next;
 222         if (!n) {
 223                 m_freem(m);
 224                 return NULL;    /* mbuf chain too short */
 225         }
 226
 227         /*
 228          * the target data is on <n, off>.
 229          * if we got enough data on the mbuf "n", we're done.
 230          */
 231         if ((off == 0 || offp) && len <= n->m_len - off)
 232                 goto ok;
 233
 234 #if defined(PULLDOWN_STAT) && defined(INET6)
 235         ip6stat.ip6s_pulldown_copy++;
 236 #endif
 237
 238         /*
 239          * when len < n->m_len - off and off != 0, it is a special case.
 240          * len bytes from <n, off> sits in single mbuf, but the caller does
 241          * not like the starting position (off).
 242          * chop the current mbuf into two pieces, set off to 0.
 243          */
 244         if (len < n->m_len - off) {
 245                 o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
 246                 if (o == NULL) {
 247                         m_freem(m);
 248                         return NULL;    /* ENOBUFS */
 249                 }
 250                 n->m_len = off;
 251                 o->m_next = n->m_next;
 252                 n->m_next = o;
 253                 n = n->m_next;
 254                 off = 0;
 255                 goto ok;
 256         }
 257
 258         /*
 259          * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
 260          * and construct contiguous mbuf with m_len == len.
 261          * note that hlen + tlen == len, and tlen > 0.
 262          */
 263         hlen = n->m_len - off;
 264         tlen = len - hlen;
 265
 266         /*
 267          * ensure that we have enough trailing data on mbuf chain.
 268          * if not, we can do nothing about the chain.
 269          */
 270         olen = 0;
 271         for (o = n->m_next; o != NULL; o = o->m_next)
 272                 olen += o->m_len;
 273         if (hlen + olen < len) {
 274                 m_freem(m);
 275                 return NULL;    /* mbuf chain too short */
 276         }
 277
 278         /*
 279          * easy cases first.
 280          * we need to use m_copydata() to get data from <n->m_next, 0>.
 281          */
 282         if ((n->m_flags & M_EXT) == 0)
 283                 sharedcluster = 0;
 284         else {
 285 #ifdef __bsdi__
 286                 if (n->m_ext.ext_func)
 287 #else
 288                 if (n->m_ext.ext_free)
 289 #endif
 290                         sharedcluster = 1;
 291 #ifdef __NetBSD__
 292                 else if (MCLISREFERENCED(n))
 293 #else
 294                 else if (mclrefcnt[mtocl(n->m_ext.ext_buf)] > 1)
 295 #endif
 296                         sharedcluster = 1;
 297                 else
 298                         sharedcluster = 0;
 299         }
 300         if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
 301          && !sharedcluster) {
 302                 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
 303                 n->m_len += tlen;
 304                 m_adj(n->m_next, tlen);
 305                 goto ok;
 306         }
 307         if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
 308          && !sharedcluster) {
 309                 n->m_next->m_data -= hlen;
 310                 n->m_next->m_len += hlen;
 311                 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
 312                 n->m_len -= hlen;
 313                 n = n->m_next;
 314                 off = 0;
 315                 goto ok;
 316         }
 317
 318         /*
 319          * now, we need to do the hard way.  don't m_copy as there's no room
 320          * on both end.
 321          */
 322 #if defined(PULLDOWN_STAT) && defined(INET6)
 323         ip6stat.ip6s_pulldown_alloc++;
 324 #endif
 325         MGET(o, M_DONTWAIT, m->m_type);
 326         if (o == NULL) {
 327                 m_freem(m);
 328                 return NULL;    /* ENOBUFS */
 329         }
 330         if (len > MHLEN) {      /* use MHLEN just for safety */
 331                 MCLGET(o, M_DONTWAIT);
 332                 if ((o->m_flags & M_EXT) == 0) {
 333                         m_freem(m);
 334                         m_free(o);
 335                         return NULL;    /* ENOBUFS */
 336                 }
 337         }
 338         /* get hlen from <n, off> into <o, 0> */
 339         o->m_len = hlen;
 340         bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
 341         n->m_len -= hlen;
 342         /* get tlen from <n->m_next, 0> into <o, hlen> */
 343         m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
 344         o->m_len += tlen;
 345         m_adj(n->m_next, tlen);
 346         o->m_next = n->m_next;
 347         n->m_next = o;
 348         n = o;
 349         off = 0;
 350
 351 ok:
 352 #ifdef PULLDOWN_DEBUG
 353     {
 354         struct mbuf *t;
 355         printf("after:");
 356         for (t = m; t; t = t->m_next)
 357                 printf("%c%d", t == n ? '*' : ' ', t->m_len);
 358         printf(" (off=%d)\n", off);
 359     }
 360 #endif
 361         if (offp)
 362                 *offp = off;
 363         return n;
 364 }
 365
 366 /*
 367  * pkthdr.aux chain manipulation.
 368  * we don't allow clusters at this moment.
 369  */
 370 struct mbuf *
 371 m_aux_add(m, af, type)
 372         struct mbuf *m;
 373         int af, type;
 374 {
 375         struct mbuf *n;
 376         struct mauxtag *t;
 377
 378         if ((m->m_flags & M_PKTHDR) == 0)
 379                 return NULL;
 380
 381         n = m_aux_find(m, af, type);
 382         if (n)
 383                 return n;
 384
 385         MGET(n, M_DONTWAIT, m->m_type);
 386         if (n == NULL)
 387                 return NULL;
 388
 389         t = mtod(n, struct mauxtag *);
 390         t->af = af;
 391         t->type = type;
 392         n->m_data += sizeof(struct mauxtag);
 393         n->m_len = 0;
 394         n->m_next = m->m_pkthdr.aux;
 395         m->m_pkthdr.aux = n;
 396         return n;
 397 }
 398
 399 struct mbuf *
 400 m_aux_find(m, af, type)
 401         struct mbuf *m;
 402         int af, type;
 403 {
 404         struct mbuf *n;
 405         struct mauxtag *t;
 406
 407         if ((m->m_flags & M_PKTHDR) == 0)
 408                 return NULL;
 409
 410         for (n = m->m_pkthdr.aux; n; n = n->m_next) {
 411                 t = (struct mauxtag *)n->m_dat;
 412                 if (t->af == af && t->type == type)
 413                         return n;
 414         }
 415         return NULL;
 416 }
 417
 418 void
 419 m_aux_delete(m, victim)
 420         struct mbuf *m;
 421         struct mbuf *victim;
 422 {
 423         struct mbuf *n, *prev, *next;
 424         struct mauxtag *t;
 425
 426         if ((m->m_flags & M_PKTHDR) == 0)
 427                 return;
 428
 429         prev = NULL;
 430         n = m->m_pkthdr.aux;
 431         while (n) {
 432                 t = (struct mauxtag *)n->m_dat;
 433                 next = n->m_next;
 434                 if (n == victim) {
 435                         if (prev)
 436                                 prev->m_next = n->m_next;
 437                         else
 438                                 m->m_pkthdr.aux = n->m_next;
 439                         n->m_next = NULL;
 440                         m_free(n);
 441                 } else
 442                         prev = n;
 443                 n = next;
 444         }
 445 }