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
  89 /*#define PULLDOWN_DEBUG*/
  90
  91 #include <sys/param.h>
  92 #include <sys/systm.h>
  93 #include <sys/proc.h>
  94 #include <sys/malloc.h>
  95 #include <sys/mbuf.h>
  96 #if defined(PULLDOWN_STAT) && defined(INET6)
  97 #include <netinet/in.h>
  98 #include <netinet/ip6.h>
  99 #include <netinet6/ip6_var.h>
 100 #endif
 101
 102 /*
 103  * ensure that [off, off + len) is contiguous on the mbuf chain "m".
 104  * packet chain before "off" is kept untouched.
 105  * if offp == NULL, the target will start at <retval, 0> on resulting chain.
 106  * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
 107  *
 108  * on error return (NULL return value), original "m" will be freed.
 109  *
 110  * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)
 111  */
 112 struct mbuf *
 113 m_pulldown(m, off, len, offp)
 114         struct mbuf *m;
 115         int off, len;
 116         int *offp;
 117 {
 118         struct mbuf *n, *o;
 119         int hlen, tlen, olen;
 120         int sharedcluster;
 121 #if defined(PULLDOWN_STAT) && defined(INET6)
 122         static struct mbuf *prev = NULL;
 123         int prevlen = 0, prevmlen = 0;
 124 #endif
 125
 126         /* check invalid arguments. */
 127         if (m == NULL)
 128                 panic("m == NULL in m_pulldown()");
 129         if (len > MCLBYTES) {
 130                 m_freem(m);
 131                 return NULL;    /* impossible */
 132         }
 133
 134 #if defined(PULLDOWN_STAT) && defined(INET6)
 135         ip6stat.ip6s_pulldown++;
 136 #endif
 137
 138 #if defined(PULLDOWN_STAT) && defined(INET6)
 139         /* statistics for m_pullup */
 140         ip6stat.ip6s_pullup++;
 141         if (off + len > MHLEN)
 142                 ip6stat.ip6s_pullup_fail++;
 143         else {
 144                 int dlen, mlen;
 145
 146                 dlen = (prev == m) ? prevlen : m->m_len;
 147                 mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);
 148
 149                 if (dlen >= off + len)
 150                         ip6stat.ip6s_pullup--; /* call will not be made! */
 151                 else if ((m->m_flags & M_EXT) != 0) {
 152                         ip6stat.ip6s_pullup_alloc++;
 153                         ip6stat.ip6s_pullup_copy++;
 154                 } else {
 155                         if (mlen >= off + len)
 156                                 ip6stat.ip6s_pullup_copy++;
 157                         else {
 158                                 ip6stat.ip6s_pullup_alloc++;
 159                                 ip6stat.ip6s_pullup_copy++;
 160                         }
 161                 }
 162
 163                 prevlen = off + len;
 164                 prevmlen = MHLEN;
 165         }
 166
 167         /* statistics for m_pullup2 */
 168         ip6stat.ip6s_pullup2++;
 169         if (off + len > MCLBYTES)
 170                 ip6stat.ip6s_pullup2_fail++;
 171         else {
 172                 int dlen, mlen;
 173
 174                 dlen = (prev == m) ? prevlen : m->m_len;
 175                 mlen = (prev == m) ? prevmlen : m->m_len + M_TRAILINGSPACE(m);
 176                 prevlen = off + len;
 177                 prevmlen = mlen;
 178
 179                 if (dlen >= off + len)
 180                         ip6stat.ip6s_pullup2--; /* call will not be made! */
 181                 else if ((m->m_flags & M_EXT) != 0) {
 182                         ip6stat.ip6s_pullup2_alloc++;
 183                         ip6stat.ip6s_pullup2_copy++;
 184                         prevmlen = (off + len > MHLEN) ? MCLBYTES : MHLEN;
 185                 } else {
 186                         if (mlen >= off + len)
 187                                 ip6stat.ip6s_pullup2_copy++;
 188                         else {
 189                                 ip6stat.ip6s_pullup2_alloc++;
 190                                 ip6stat.ip6s_pullup2_copy++;
 191                                 prevmlen = (off + len > MHLEN) ? MCLBYTES
 192                                                                : MHLEN;
 193                         }
 194                 }
 195         }
 196
 197         prev = m;
 198 #endif
 199
 200 #ifdef PULLDOWN_DEBUG
 201     {
 202         struct mbuf *t;
 203         printf("before:");
 204         for (t = m; t; t = t->m_next)
 205                 printf(" %d", t->m_len);
 206         printf("\n");
 207     }
 208 #endif
 209         n = m;
 210         while (n != NULL && off > 0) {
 211                 if (n->m_len > off)
 212                         break;
 213                 off -= n->m_len;
 214                 n = n->m_next;
 215         }
 216         /* be sure to point non-empty mbuf */
 217         while (n != NULL && n->m_len == 0)
 218                 n = n->m_next;
 219         if (!n) {
 220                 m_freem(m);
 221                 return NULL;    /* mbuf chain too short */
 222         }
 223
 224         /*
 225          * the target data is on <n, off>.
 226          * if we got enough data on the mbuf "n", we're done.
 227          */
 228         if ((off == 0 || offp) && len <= n->m_len - off)
 229                 goto ok;
 230
 231 #if defined(PULLDOWN_STAT) && defined(INET6)
 232         ip6stat.ip6s_pulldown_copy++;
 233 #endif
 234
 235         /*
 236          * when len < n->m_len - off and off != 0, it is a special case.
 237          * len bytes from <n, off> sits in single mbuf, but the caller does
 238          * not like the starting position (off).
 239          * chop the current mbuf into two pieces, set off to 0.
 240          */
 241         if (len < n->m_len - off) {
 242                 o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
 243                 if (o == NULL) {
 244                         m_freem(m);
 245                         return NULL;    /* ENOBUFS */
 246                 }
 247                 n->m_len = off;
 248                 o->m_next = n->m_next;
 249                 n->m_next = o;
 250                 n = n->m_next;
 251                 off = 0;
 252                 goto ok;
 253         }
 254
 255         /*
 256          * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
 257          * and construct contiguous mbuf with m_len == len.
 258          * note that hlen + tlen == len, and tlen > 0.
 259          */
 260         hlen = n->m_len - off;
 261         tlen = len - hlen;
 262
 263         /*
 264          * ensure that we have enough trailing data on mbuf chain.
 265          * if not, we can do nothing about the chain.
 266          */
 267         olen = 0;
 268         for (o = n->m_next; o != NULL; o = o->m_next)
 269                 olen += o->m_len;
 270         if (hlen + olen < len) {
 271                 m_freem(m);
 272                 return NULL;    /* mbuf chain too short */
 273         }
 274
 275         /*
 276          * easy cases first.
 277          * we need to use m_copydata() to get data from <n->m_next, 0>.
 278          */
 279         if ((n->m_flags & M_EXT) == 0)
 280                 sharedcluster = 0;
 281         else {
 282 #ifdef __bsdi__
 283                 if (n->m_ext.ext_func)
 284 #else
 285                 if (n->m_ext.ext_free)
 286 #endif
 287                         sharedcluster = 1;
 288 #ifdef __NetBSD__
 289                 else if (MCLISREFERENCED(n))
 290 #else
 291                 else if (mclrefcnt[mtocl(n->m_ext.ext_buf)] > 1)
 292 #endif
 293                         sharedcluster = 1;
 294                 else
 295                         sharedcluster = 0;
 296         }
 297         if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
 298          && !sharedcluster) {
 299                 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
 300                 n->m_len += tlen;
 301                 m_adj(n->m_next, tlen);
 302                 goto ok;
 303         }
 304         if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
 305          && !sharedcluster) {
 306                 n->m_next->m_data -= hlen;
 307                 n->m_next->m_len += hlen;
 308                 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
 309                 n->m_len -= hlen;
 310                 n = n->m_next;
 311                 off = 0;
 312                 goto ok;
 313         }
 314
 315         /*
 316          * now, we need to do the hard way.  don't m_copy as there's no room
 317          * on both end.
 318          */
 319 #if defined(PULLDOWN_STAT) && defined(INET6)
 320         ip6stat.ip6s_pulldown_alloc++;
 321 #endif
 322         MGET(o, M_DONTWAIT, m->m_type);
 323         if (o == NULL) {
 324                 m_freem(m);
 325                 return NULL;    /* ENOBUFS */
 326         }
 327         if (len > MHLEN) {      /* use MHLEN just for safety */
 328                 MCLGET(o, M_DONTWAIT);
 329                 if ((o->m_flags & M_EXT) == 0) {
 330                         m_freem(m);
 331                         m_free(o);
 332                         return NULL;    /* ENOBUFS */
 333                 }
 334         }
 335         /* get hlen from <n, off> into <o, 0> */
 336         o->m_len = hlen;
 337         bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
 338         n->m_len -= hlen;
 339         /* get tlen from <n->m_next, 0> into <o, hlen> */
 340         m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
 341         o->m_len += tlen;
 342         m_adj(n->m_next, tlen);
 343         o->m_next = n->m_next;
 344         n->m_next = o;
 345         n = o;
 346         off = 0;
 347
 348 ok:
 349 #ifdef PULLDOWN_DEBUG
 350     {
 351         struct mbuf *t;
 352         printf("after:");
 353         for (t = m; t; t = t->m_next)
 354                 printf("%c%d", t == n ? '*' : ' ', t->m_len);
 355         printf(" (off=%d)\n", off);
 356     }
 357 #endif
 358         if (offp)
 359                 *offp = off;
 360         return n;
 361 }
 362
 363 /*
 364  * pkthdr.aux chain manipulation.
 365  * we don't allow clusters at this moment.
 366  */
 367 struct mbuf *
 368 m_aux_add(m, af, type)
 369         struct mbuf *m;
 370         int af, type;
 371 {
 372         struct mbuf *n;
 373         struct mauxtag *t;
 374
 375         if ((m->m_flags & M_PKTHDR) == 0)
 376                 return NULL;
 377
 378         n = m_aux_find(m, af, type);
 379         if (n)
 380                 return n;
 381
 382         MGET(n, M_WAIT, m->m_type);
 383         if (n == NULL)
 384                 return NULL;
 385
 386         t = mtod(n, struct mauxtag *);
 387         t->af = af;
 388         t->type = type;
 389         n->m_data += sizeof(struct mauxtag);
 390         n->m_len = 0;
 391         n->m_next = m->m_pkthdr.aux;
 392         m->m_pkthdr.aux = n;
 393         return n;
 394 }
 395
 396 struct mbuf *
 397 m_aux_find(m, af, type)
 398         struct mbuf *m;
 399         int af, type;
 400 {
 401         struct mbuf *n;
 402         struct mauxtag *t;
 403
 404         if ((m->m_flags & M_PKTHDR) == 0)
 405                 return NULL;
 406
 407         for (n = m->m_pkthdr.aux; n; n = n->m_next) {
 408                 t = (struct mauxtag *)n->m_dat;
 409                 if (t->af == af && t->type == type)
 410                         return n;
 411         }
 412         return NULL;
 413 }
 414
 415 void
 416 m_aux_delete(m, victim)
 417         struct mbuf *m;
 418         struct mbuf *victim;
 419 {
 420         struct mbuf *n, *prev, *next;
 421         struct mauxtag *t;
 422
 423         if ((m->m_flags & M_PKTHDR) == 0)
 424                 return;
 425
 426         prev = NULL;
 427         n = m->m_pkthdr.aux;
 428         while (n) {
 429                 t = (struct mauxtag *)n->m_dat;
 430                 next = n->m_next;
 431                 if (n == victim) {
 432                         if (prev)
 433                                 prev->m_next = n->m_next;
 434                         else
 435                                 m->m_pkthdr.aux = n->m_next;
 436                         n->m_next = NULL;
 437                         m_free(n);
 438                 } else
 439                         prev = n;
 440                 n = next;
 441         }
 442 }