src/libs/compat/freebsd_network/fbsd_mbuf2.c

   1 /*      $KAME: uipc_mbuf2.c,v 1.31 2001/11/28 11:08:53 itojun Exp $     */
   2 /*      $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $   */
   3
   4 /*-
   5  * Copyright (C) 1999 WIDE Project.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the project nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32 /*-
  33  * Copyright (c) 1982, 1986, 1988, 1991, 1993
  34  *      The Regents of the University of California.  All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  *      @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95
  61  */
  62 #include <sys/cdefs.h>
  63 __FBSDID("$FreeBSD$");
  64
  65 /*#define PULLDOWN_DEBUG*/
  66
  67 #include <sys/param.h>
  68 #include <sys/systm.h>
  69 #include <sys/kernel.h>
  70 #include <sys/lock.h>
  71 #include <sys/malloc.h>
  72 #include <sys/mbuf.h>
  73 #include <sys/mutex.h>
  74
  75 #include <security/mac/mac_framework.h>
  76
  77 #define malloc(size, tag, flags) kernel_malloc(size, tag, flags)
  78 #define free(pointer, tag) kernel_free(pointer, tag)
  79
  80 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
  81 static struct mbuf *m_dup1(struct mbuf *, int, int, int);
  82
  83 /*
  84  * ensure that [off, off + len) is contiguous on the mbuf chain "m".
  85  * packet chain before "off" is kept untouched.
  86  * if offp == NULL, the target will start at <retval, 0> on resulting chain.
  87  * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
  88  *
  89  * on error return (NULL return value), original "m" will be freed.
  90  *
  91  * XXX: M_TRAILINGSPACE/M_LEADINGSPACE only permitted on writable ext_buf.
  92  */
  93 struct mbuf *
  94 m_pulldown(struct mbuf *m, int off, int len, int *offp)
  95 {
  96         struct mbuf *n, *o;
  97         int hlen, tlen, olen;
  98         int writable;
  99
 100         /* check invalid arguments. */
 101         if (m == NULL)
 102                 panic("m == NULL in m_pulldown()");
 103         if (len > MCLBYTES) {
 104                 m_freem(m);
 105                 return NULL;    /* impossible */
 106         }
 107
 108 #ifdef PULLDOWN_DEBUG
 109     {
 110         struct mbuf *t;
 111         printf("before:");
 112         for (t = m; t; t = t->m_next)
 113                 printf(" %d", t->m_len);
 114         printf("\n");
 115     }
 116 #endif
 117         n = m;
 118         while (n != NULL && off > 0) {
 119                 if (n->m_len > off)
 120                         break;
 121                 off -= n->m_len;
 122                 n = n->m_next;
 123         }
 124         /* be sure to point non-empty mbuf */
 125         while (n != NULL && n->m_len == 0)
 126                 n = n->m_next;
 127         if (!n) {
 128                 m_freem(m);
 129                 return NULL;    /* mbuf chain too short */
 130         }
 131
 132         /*
 133          * XXX: This code is flawed because it considers a "writable" mbuf
 134          *      data region to require all of the following:
 135          *        (i) mbuf _has_ to have M_EXT set; if it is just a regular
 136          *            mbuf, it is still not considered "writable."
 137          *        (ii) since mbuf has M_EXT, the ext_type _has_ to be
 138          *             EXT_CLUSTER. Anything else makes it non-writable.
 139          *        (iii) M_WRITABLE() must evaluate true.
 140          *      Ideally, the requirement should only be (iii).
 141          *
 142          * If we're writable, we're sure we're writable, because the ref. count
 143          * cannot increase from 1, as that would require posession of mbuf
 144          * n by someone else (which is impossible). However, if we're _not_
 145          * writable, we may eventually become writable )if the ref. count drops
 146          * to 1), but we'll fail to notice it unless we re-evaluate
 147          * M_WRITABLE(). For now, we only evaluate once at the beginning and
 148          * live with this.
 149          */
 150         /*
 151          * XXX: This is dumb. If we're just a regular mbuf with no M_EXT,
 152          *      then we're not "writable," according to this code.
 153          */
 154         writable = 0;
 155         if ((n->m_flags & M_EXT) == 0 ||
 156             (n->m_ext.ext_type == EXT_CLUSTER && M_WRITABLE(n)))
 157                 writable = 1;
 158
 159         /*
 160          * the target data is on <n, off>.
 161          * if we got enough data on the mbuf "n", we're done.
 162          */
 163         if ((off == 0 || offp) && len <= n->m_len - off && writable)
 164                 goto ok;
 165
 166         /*
 167          * when len <= n->m_len - off and off != 0, it is a special case.
 168          * len bytes from <n, off> sits in single mbuf, but the caller does
 169          * not like the starting position (off).
 170          * chop the current mbuf into two pieces, set off to 0.
 171          */
 172         if (len <= n->m_len - off) {
 173                 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT);
 174                 if (o == NULL) {
 175                         m_freem(m);
 176                         return NULL;    /* ENOBUFS */
 177                 }
 178                 n->m_len = off;
 179                 o->m_next = n->m_next;
 180                 n->m_next = o;
 181                 n = n->m_next;
 182                 off = 0;
 183                 goto ok;
 184         }
 185
 186         /*
 187          * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
 188          * and construct contiguous mbuf with m_len == len.
 189          * note that hlen + tlen == len, and tlen > 0.
 190          */
 191         hlen = n->m_len - off;
 192         tlen = len - hlen;
 193
 194         /*
 195          * ensure that we have enough trailing data on mbuf chain.
 196          * if not, we can do nothing about the chain.
 197          */
 198         olen = 0;
 199         for (o = n->m_next; o != NULL; o = o->m_next)
 200                 olen += o->m_len;
 201         if (hlen + olen < len) {
 202                 m_freem(m);
 203                 return NULL;    /* mbuf chain too short */
 204         }
 205
 206         /*
 207          * easy cases first.
 208          * we need to use m_copydata() to get data from <n->m_next, 0>.
 209          */
 210         if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
 211          && writable) {
 212                 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
 213                 n->m_len += tlen;
 214                 m_adj(n->m_next, tlen);
 215                 goto ok;
 216         }
 217         if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
 218          && writable) {
 219                 n->m_next->m_data -= hlen;
 220                 n->m_next->m_len += hlen;
 221                 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
 222                 n->m_len -= hlen;
 223                 n = n->m_next;
 224                 off = 0;
 225                 goto ok;
 226         }
 227
 228         /*
 229          * now, we need to do the hard way.  don't m_copy as there's no room
 230          * on both end.
 231          */
 232         if (len > MLEN)
 233                 o = m_getcl(M_DONTWAIT, m->m_type, 0);
 234         else
 235                 o = m_get(M_DONTWAIT, m->m_type);
 236         if (!o) {
 237                 m_freem(m);
 238                 return NULL;    /* ENOBUFS */
 239         }
 240         /* get hlen from <n, off> into <o, 0> */
 241         o->m_len = hlen;
 242         bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
 243         n->m_len -= hlen;
 244         /* get tlen from <n->m_next, 0> into <o, hlen> */
 245         m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
 246         o->m_len += tlen;
 247         m_adj(n->m_next, tlen);
 248         o->m_next = n->m_next;
 249         n->m_next = o;
 250         n = o;
 251         off = 0;
 252
 253 ok:
 254 #ifdef PULLDOWN_DEBUG
 255     {
 256         struct mbuf *t;
 257         printf("after:");
 258         for (t = m; t; t = t->m_next)
 259                 printf("%c%d", t == n ? '*' : ' ', t->m_len);
 260         printf(" (off=%d)\n", off);
 261     }
 262 #endif
 263         if (offp)
 264                 *offp = off;
 265         return n;
 266 }
 267
 268 static struct mbuf *
 269 m_dup1(struct mbuf *m, int off, int len, int wait)
 270 {
 271         struct mbuf *n;
 272         int copyhdr;
 273
 274         if (len > MCLBYTES)
 275                 return NULL;
 276         if (off == 0 && (m->m_flags & M_PKTHDR) != 0)
 277                 copyhdr = 1;
 278         else
 279                 copyhdr = 0;
 280         if (len >= MINCLSIZE) {
 281                 if (copyhdr == 1)
 282                         n = m_getcl(wait, m->m_type, M_PKTHDR);
 283                 else
 284                         n = m_getcl(wait, m->m_type, 0);
 285         } else {
 286                 if (copyhdr == 1)
 287                         n = m_gethdr(wait, m->m_type);
 288                 else
 289                         n = m_get(wait, m->m_type);
 290         }
 291         if (!n)
 292                 return NULL; /* ENOBUFS */
 293
 294         if (copyhdr && !m_dup_pkthdr(n, m, wait)) {
 295                 m_free(n);
 296                 return NULL;
 297         }
 298         m_copydata(m, off, len, mtod(n, caddr_t));
 299         n->m_len = len;
 300         return n;
 301 }
 302
 303 /* Free a packet tag. */
 304 void
 305 m_tag_free_default(struct m_tag *t)
 306 {
 307 #ifdef MAC
 308         if (t->m_tag_id == PACKET_TAG_MACLABEL)
 309                 mac_mbuf_tag_destroy(t);
 310 #endif
 311         free(t, M_PACKET_TAGS);
 312 }
 313
 314 /* Get a packet tag structure along with specified data following. */
 315 struct m_tag *
 316 m_tag_alloc(u_int32_t cookie, int type, int len, int wait)
 317 {
 318         struct m_tag *t;
 319
 320         MBUF_CHECKSLEEP(wait);
 321         if (len < 0)
 322                 return NULL;
 323         t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait);
 324         if (t == NULL)
 325                 return NULL;
 326         m_tag_setup(t, cookie, type, len);
 327         t->m_tag_free = m_tag_free_default;
 328         return t;
 329 }
 330
 331 /* Unlink and free a packet tag. */
 332 void
 333 m_tag_delete(struct mbuf *m, struct m_tag *t)
 334 {
 335
 336         KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t));
 337         m_tag_unlink(m, t);
 338         m_tag_free(t);
 339 }
 340
 341 /* Unlink and free a packet tag chain, starting from given tag. */
 342 void
 343 m_tag_delete_chain(struct mbuf *m, struct m_tag *t)
 344 {
 345         struct m_tag *p, *q;
 346
 347         KASSERT(m, ("m_tag_delete_chain: null mbuf"));
 348         if (t != NULL)
 349                 p = t;
 350         else
 351                 p = SLIST_FIRST(&m->m_pkthdr.tags);
 352         if (p == NULL)
 353                 return;
 354         while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
 355                 m_tag_delete(m, q);
 356         m_tag_delete(m, p);
 357 }
 358
 359 /*
 360  * Strip off all tags that would normally vanish when
 361  * passing through a network interface.  Only persistent
 362  * tags will exist after this; these are expected to remain
 363  * so long as the mbuf chain exists, regardless of the
 364  * path the mbufs take.
 365  */
 366 void
 367 m_tag_delete_nonpersistent(struct mbuf *m)
 368 {
 369         struct m_tag *p, *q;
 370
 371         SLIST_FOREACH_SAFE(p, &m->m_pkthdr.tags, m_tag_link, q)
 372                 if ((p->m_tag_id & MTAG_PERSISTENT) == 0)
 373                         m_tag_delete(m, p);
 374 }
 375
 376 /* Find a tag, starting from a given position. */
 377 struct m_tag *
 378 m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t)
 379 {
 380         struct m_tag *p;
 381
 382         KASSERT(m, ("m_tag_locate: null mbuf"));
 383         if (t == NULL)
 384                 p = SLIST_FIRST(&m->m_pkthdr.tags);
 385         else
 386                 p = SLIST_NEXT(t, m_tag_link);
 387         while (p != NULL) {
 388                 if (p->m_tag_cookie == cookie && p->m_tag_id == type)
 389                         return p;
 390                 p = SLIST_NEXT(p, m_tag_link);
 391         }
 392         return NULL;
 393 }
 394
 395 /* Copy a single tag. */
 396 struct m_tag *
 397 m_tag_copy(struct m_tag *t, int how)
 398 {
 399         struct m_tag *p;
 400
 401         MBUF_CHECKSLEEP(how);
 402         KASSERT(t, ("m_tag_copy: null tag"));
 403         p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how);
 404         if (p == NULL)
 405                 return (NULL);
 406 #ifdef MAC
 407         /*
 408          * XXXMAC: we should probably pass off the initialization, and
 409          * copying here?  can we hide that PACKET_TAG_MACLABEL is
 410          * special from the mbuf code?
 411          */
 412         if (t->m_tag_id == PACKET_TAG_MACLABEL) {
 413                 if (mac_mbuf_tag_init(p, how) != 0) {
 414                         m_tag_free(p);
 415                         return (NULL);
 416                 }
 417                 mac_mbuf_tag_copy(t, p);
 418         } else
 419 #endif
 420                 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */
 421         return p;
 422 }
 423
 424 /*
 425  * Copy two tag chains. The destination mbuf (to) loses any attached
 426  * tags even if the operation fails. This should not be a problem, as
 427  * m_tag_copy_chain() is typically called with a newly-allocated
 428  * destination mbuf.
 429  */
 430 int
 431 m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int how)
 432 {
 433         struct m_tag *p, *t, *tprev = NULL;
 434
 435         MBUF_CHECKSLEEP(how);
 436         KASSERT(to && from,
 437                 ("m_tag_copy_chain: null argument, to %p from %p", to, from));
 438         m_tag_delete_chain(to, NULL);
 439         SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
 440                 t = m_tag_copy(p, how);
 441                 if (t == NULL) {
 442                         m_tag_delete_chain(to, NULL);
 443                         return 0;
 444                 }
 445                 if (tprev == NULL)
 446                         SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
 447                 else
 448                         SLIST_INSERT_AFTER(tprev, t, m_tag_link);
 449                 tprev = t;
 450         }
 451         return 1;
 452 }