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 $ */
5 * Copyright (C) 1999 WIDE Project.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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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
33 * Copyright (c) 1982, 1986, 1988, 1991, 1993
34 * The Regents of the University of California. All rights reserved.
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
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.
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
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60 * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
66 /*#define PULLDOWN_DEBUG*/
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/kernel.h>
75 #include <sys/malloc.h>
77 #include <sys/mutex.h>
79 static MALLOC_DEFINE(M_PACKET_TAGS, MBUF_TAG_MEM_NAME,
80 "packet-attached information");
82 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
83 static struct mbuf *m_dup1(struct mbuf *, int, int, int);
86 * ensure that [off, off + len) is contiguous on the mbuf chain "m".
87 * packet chain before "off" is kept untouched.
88 * if offp == NULL, the target will start at <retval, 0> on resulting chain.
89 * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
91 * on error return (NULL return value), original "m" will be freed.
93 * XXX: M_TRAILINGSPACE/M_LEADINGSPACE only permitted on writable ext_buf.
96 m_pulldown(struct mbuf *m, int off, int len, int *offp)
102 /* check invalid arguments. */
104 panic("m == NULL in m_pulldown()");
105 if (len > MCLBYTES) {
107 return NULL; /* impossible */
110 #ifdef PULLDOWN_DEBUG
114 for (t = m; t; t = t->m_next)
115 printf(" %d", t->m_len);
120 while (n != NULL && off > 0) {
126 /* be sure to point non-empty mbuf */
127 while (n != NULL && n->m_len == 0)
131 return NULL; /* mbuf chain too short */
135 * XXX: This code is flawed because it considers a "writable" mbuf
136 * data region to require all of the following:
137 * (i) mbuf _has_ to have M_EXT set; if it is just a regular
138 * mbuf, it is still not considered "writable."
139 * (ii) since mbuf has M_EXT, the ext_type _has_ to be
140 * EXT_CLUSTER. Anything else makes it non-writable.
141 * (iii) M_WRITABLE() must evaluate true.
142 * Ideally, the requirement should only be (iii).
144 * If we're writable, we're sure we're writable, because the ref. count
145 * cannot increase from 1, as that would require posession of mbuf
146 * n by someone else (which is impossible). However, if we're _not_
147 * writable, we may eventually become writable )if the ref. count drops
148 * to 1), but we'll fail to notice it unless we re-evaluate
149 * M_WRITABLE(). For now, we only evaluate once at the beginning and
153 * XXX: This is dumb. If we're just a regular mbuf with no M_EXT,
154 * then we're not "writable," according to this code.
157 if ((n->m_flags & M_EXT) == 0 ||
158 (n->m_ext.ext_type == EXT_CLUSTER && M_WRITABLE(n)))
162 * the target data is on <n, off>.
163 * if we got enough data on the mbuf "n", we're done.
165 if ((off == 0 || offp) && len <= n->m_len - off && writable)
169 * when len <= n->m_len - off and off != 0, it is a special case.
170 * len bytes from <n, off> sits in single mbuf, but the caller does
171 * not like the starting position (off).
172 * chop the current mbuf into two pieces, set off to 0.
174 if (len <= n->m_len - off) {
175 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT);
178 return NULL; /* ENOBUFS */
181 o->m_next = n->m_next;
189 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
190 * and construct contiguous mbuf with m_len == len.
191 * note that hlen + tlen == len, and tlen > 0.
193 hlen = n->m_len - off;
197 * ensure that we have enough trailing data on mbuf chain.
198 * if not, we can do nothing about the chain.
201 for (o = n->m_next; o != NULL; o = o->m_next)
203 if (hlen + olen < len) {
205 return NULL; /* mbuf chain too short */
210 * we need to use m_copydata() to get data from <n->m_next, 0>.
212 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
214 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
216 m_adj(n->m_next, tlen);
219 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
221 n->m_next->m_data -= hlen;
222 n->m_next->m_len += hlen;
223 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
231 * now, we need to do the hard way. don't m_copy as there's no room
235 o = m_getcl(M_DONTWAIT, m->m_type, 0);
237 o = m_get(M_DONTWAIT, m->m_type);
240 return NULL; /* ENOBUFS */
242 /* get hlen from <n, off> into <o, 0> */
244 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
246 /* get tlen from <n->m_next, 0> into <o, hlen> */
247 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
249 m_adj(n->m_next, tlen);
250 o->m_next = n->m_next;
256 #ifdef PULLDOWN_DEBUG
260 for (t = m; t; t = t->m_next)
261 printf("%c%d", t == n ? '*' : ' ', t->m_len);
262 printf(" (off=%d)\n", off);
271 m_dup1(struct mbuf *m, int off, int len, int wait)
278 if (off == 0 && (m->m_flags & M_PKTHDR) != 0)
282 if (len >= MINCLSIZE) {
284 n = m_getcl(wait, m->m_type, M_PKTHDR);
286 n = m_getcl(wait, m->m_type, 0);
289 n = m_gethdr(wait, m->m_type);
291 n = m_get(wait, m->m_type);
294 return NULL; /* ENOBUFS */
296 if (copyhdr && !m_dup_pkthdr(n, m, wait)) {
300 m_copydata(m, off, len, mtod(n, caddr_t));
305 /* Free a packet tag. */
307 m_tag_free_default(struct m_tag *t)
310 if (t->m_tag_id == PACKET_TAG_MACLABEL)
311 mac_destroy_mbuf_tag(t);
313 free(t, M_PACKET_TAGS);
316 /* Get a packet tag structure along with specified data following. */
318 m_tag_alloc(u_int32_t cookie, int type, int len, int wait)
322 MBUF_CHECKSLEEP(wait);
325 t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait);
328 m_tag_setup(t, cookie, type, len);
329 t->m_tag_free = m_tag_free_default;
333 /* Unlink and free a packet tag. */
335 m_tag_delete(struct mbuf *m, struct m_tag *t)
338 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t));
343 /* Unlink and free a packet tag chain, starting from given tag. */
345 m_tag_delete_chain(struct mbuf *m, struct m_tag *t)
349 KASSERT(m, ("m_tag_delete_chain: null mbuf"));
353 p = SLIST_FIRST(&m->m_pkthdr.tags);
356 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
362 * Strip off all tags that would normally vanish when
363 * passing through a network interface. Only persistent
364 * tags will exist after this; these are expected to remain
365 * so long as the mbuf chain exists, regardless of the
366 * path the mbufs take.
369 m_tag_delete_nonpersistent(struct mbuf *m)
373 SLIST_FOREACH_SAFE(p, &m->m_pkthdr.tags, m_tag_link, q)
374 if ((p->m_tag_id & MTAG_PERSISTENT) == 0)
378 /* Find a tag, starting from a given position. */
380 m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t)
384 KASSERT(m, ("m_tag_locate: null mbuf"));
386 p = SLIST_FIRST(&m->m_pkthdr.tags);
388 p = SLIST_NEXT(t, m_tag_link);
390 if (p->m_tag_cookie == cookie && p->m_tag_id == type)
392 p = SLIST_NEXT(p, m_tag_link);
397 /* Copy a single tag. */
399 m_tag_copy(struct m_tag *t, int how)
403 MBUF_CHECKSLEEP(how);
404 KASSERT(t, ("m_tag_copy: null tag"));
405 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how);
410 * XXXMAC: we should probably pass off the initialization, and
411 * copying here? can we hide that PACKET_TAG_MACLABEL is
412 * special from the mbuf code?
414 if (t->m_tag_id == PACKET_TAG_MACLABEL) {
415 if (mac_init_mbuf_tag(p, how) != 0) {
419 mac_copy_mbuf_tag(t, p);
422 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */
427 * Copy two tag chains. The destination mbuf (to) loses any attached
428 * tags even if the operation fails. This should not be a problem, as
429 * m_tag_copy_chain() is typically called with a newly-allocated
433 m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int how)
435 struct m_tag *p, *t, *tprev = NULL;
437 MBUF_CHECKSLEEP(how);
439 ("m_tag_copy_chain: null argument, to %p from %p", to, from));
440 m_tag_delete_chain(to, NULL);
441 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
442 t = m_tag_copy(p, how);
444 m_tag_delete_chain(to, NULL);
448 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
450 SLIST_INSERT_AFTER(tprev, t, m_tag_link);