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 * SPDX-License-Identifier: BSD-3-Clause
7 * Copyright (C) 1999 WIDE Project.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the project nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * Copyright (c) 1982, 1986, 1988, 1991, 1993
36 * The Regents of the University of California. All rights reserved.
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
41 * 1. Redistributions of source code must retain the above copyright
42 * notice, this list of conditions and the following disclaimer.
43 * 2. Redistributions in binary form must reproduce the above copyright
44 * notice, this list of conditions and the following disclaimer in the
45 * documentation and/or other materials provided with the distribution.
46 * 3. Neither the name of the University nor the names of its contributors
47 * may be used to endorse or promote products derived from this software
48 * without specific prior written permission.
50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62 * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
68 /*#define PULLDOWN_DEBUG*/
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/kernel.h>
74 #include <sys/malloc.h>
76 #include <sys/mutex.h>
78 #include <security/mac/mac_framework.h>
80 static MALLOC_DEFINE(M_PACKET_TAGS, MBUF_TAG_MEM_NAME,
81 "packet-attached information");
83 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
84 static struct mbuf *m_dup1(struct mbuf *, int, int, int);
87 * ensure that [off, off + len) is contiguous on the mbuf chain "m".
88 * packet chain before "off" is kept untouched.
89 * if offp == NULL, the target will start at <retval, 0> on resulting chain.
90 * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
92 * on error return (NULL return value), original "m" will be freed.
94 * XXX: M_TRAILINGSPACE/M_LEADINGSPACE only permitted on writable ext_buf.
97 m_pulldown(struct mbuf *m, int off, int len, int *offp)
100 int hlen, tlen, olen;
103 /* check invalid arguments. */
104 KASSERT(m != NULL, ("%s: fix caller: m is NULL off %d len %d offp %p\n",
105 __func__, off, len, offp));
106 if (len > MCLBYTES) {
108 return NULL; /* impossible */
111 #ifdef PULLDOWN_DEBUG
115 for (t = m; t; t = t->m_next)
116 printf(" %d", t->m_len);
121 while (n != NULL && off > 0) {
127 /* be sure to point non-empty mbuf */
128 while (n != NULL && n->m_len == 0)
132 return NULL; /* mbuf chain too short */
136 * The following comment is dated but still partially applies:
138 * XXX: This code is flawed because it considers a "writable" mbuf
139 * data region to require all of the following:
140 * (i) mbuf _has_ to have M_EXT set; if it is just a regular
141 * mbuf, it is still not considered "writable."
142 * (ii) since mbuf has M_EXT, the ext_type _has_ to be
143 * EXT_CLUSTER. Anything else makes it non-writable.
144 * (iii) M_WRITABLE() must evaluate true.
145 * Ideally, the requirement should only be (iii).
147 * If we're writable, we're sure we're writable, because the ref. count
148 * cannot increase from 1, as that would require possession of mbuf
149 * n by someone else (which is impossible). However, if we're _not_
150 * writable, we may eventually become writable )if the ref. count drops
151 * to 1), but we'll fail to notice it unless we re-evaluate
152 * M_WRITABLE(). For now, we only evaluate once at the beginning and
156 if ((n->m_flags & M_EXT) == 0 ||
157 (n->m_ext.ext_type == EXT_CLUSTER && M_WRITABLE(n)))
161 * the target data is on <n, off>.
162 * if we got enough data on the mbuf "n", we're done.
164 if ((off == 0 || offp) && len <= n->m_len - off)
168 * when len <= n->m_len - off and off != 0, it is a special case.
169 * len bytes from <n, off> sits in single mbuf, but the caller does
170 * not like the starting position (off).
171 * chop the current mbuf into two pieces, set off to 0.
173 if (len <= n->m_len - off) {
174 o = m_dup1(n, off, n->m_len - off, M_NOWAIT);
177 return NULL; /* ENOBUFS */
180 o->m_next = n->m_next;
188 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
189 * and construct contiguous mbuf with m_len == len.
190 * note that hlen + tlen == len, and tlen > 0.
192 hlen = n->m_len - off;
196 * ensure that we have enough trailing data on mbuf chain.
197 * if not, we can do nothing about the chain.
200 for (o = n->m_next; o != NULL; o = o->m_next)
202 if (hlen + olen < len) {
204 return NULL; /* mbuf chain too short */
209 * we need to use m_copydata() to get data from <n->m_next, 0>.
211 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
213 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
215 m_adj(n->m_next, tlen);
218 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
219 && writable && n->m_next->m_len >= tlen) {
220 n->m_next->m_data -= hlen;
221 n->m_next->m_len += hlen;
222 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
230 * now, we need to do the hard way. don't m_copy as there's no room
234 o = m_getcl(M_NOWAIT, m->m_type, 0);
236 o = m_get(M_NOWAIT, m->m_type);
239 return NULL; /* ENOBUFS */
241 /* get hlen from <n, off> into <o, 0> */
243 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
245 /* get tlen from <n->m_next, 0> into <o, hlen> */
246 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
248 m_adj(n->m_next, tlen);
249 o->m_next = n->m_next;
255 #ifdef PULLDOWN_DEBUG
259 for (t = m; t; t = t->m_next)
260 printf("%c%d", t == n ? '*' : ' ', t->m_len);
261 printf(" (off=%d)\n", off);
270 m_dup1(struct mbuf *m, int off, int len, int wait)
277 if (off == 0 && (m->m_flags & M_PKTHDR) != 0)
281 if (len >= MINCLSIZE) {
283 n = m_getcl(wait, m->m_type, M_PKTHDR);
285 n = m_getcl(wait, m->m_type, 0);
288 n = m_gethdr(wait, m->m_type);
290 n = m_get(wait, m->m_type);
293 return NULL; /* ENOBUFS */
295 if (copyhdr && !m_dup_pkthdr(n, m, wait)) {
299 m_copydata(m, off, len, mtod(n, caddr_t));
304 /* Free a packet tag. */
306 m_tag_free_default(struct m_tag *t)
309 if (t->m_tag_id == PACKET_TAG_MACLABEL)
310 mac_mbuf_tag_destroy(t);
312 free(t, M_PACKET_TAGS);
315 /* Get a packet tag structure along with specified data following. */
317 m_tag_alloc(uint32_t cookie, int type, int len, int wait)
321 MBUF_CHECKSLEEP(wait);
324 t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait);
327 m_tag_setup(t, cookie, type, len);
328 t->m_tag_free = m_tag_free_default;
332 /* Unlink and free a packet tag. */
334 m_tag_delete(struct mbuf *m, struct m_tag *t)
337 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t));
342 /* Unlink and free a packet tag chain, starting from given tag. */
344 m_tag_delete_chain(struct mbuf *m, struct m_tag *t)
348 KASSERT(m, ("m_tag_delete_chain: null mbuf"));
352 p = SLIST_FIRST(&m->m_pkthdr.tags);
355 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
361 * Strip off all tags that would normally vanish when
362 * passing through a network interface. Only persistent
363 * tags will exist after this; these are expected to remain
364 * so long as the mbuf chain exists, regardless of the
365 * path the mbufs take.
368 m_tag_delete_nonpersistent(struct mbuf *m)
372 SLIST_FOREACH_SAFE(p, &m->m_pkthdr.tags, m_tag_link, q)
373 if ((p->m_tag_id & MTAG_PERSISTENT) == 0)
377 /* Find a tag, starting from a given position. */
379 m_tag_locate(struct mbuf *m, uint32_t cookie, int type, struct m_tag *t)
383 KASSERT(m, ("m_tag_locate: null mbuf"));
385 p = SLIST_FIRST(&m->m_pkthdr.tags);
387 p = SLIST_NEXT(t, m_tag_link);
389 if (p->m_tag_cookie == cookie && p->m_tag_id == type)
391 p = SLIST_NEXT(p, m_tag_link);
396 /* Copy a single tag. */
398 m_tag_copy(struct m_tag *t, int how)
402 MBUF_CHECKSLEEP(how);
403 KASSERT(t, ("m_tag_copy: null tag"));
404 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how);
409 * XXXMAC: we should probably pass off the initialization, and
410 * copying here? can we hide that PACKET_TAG_MACLABEL is
411 * special from the mbuf code?
413 if (t->m_tag_id == PACKET_TAG_MACLABEL) {
414 if (mac_mbuf_tag_init(p, how) != 0) {
418 mac_mbuf_tag_copy(t, p);
421 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */
426 * Copy two tag chains. The destination mbuf (to) loses any attached
427 * tags even if the operation fails. This should not be a problem, as
428 * m_tag_copy_chain() is typically called with a newly-allocated
432 m_tag_copy_chain(struct mbuf *to, const struct mbuf *from, int how)
434 struct m_tag *p, *t, *tprev = NULL;
436 MBUF_CHECKSLEEP(how);
438 ("m_tag_copy_chain: null argument, to %p from %p", to, from));
439 m_tag_delete_chain(to, NULL);
440 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
441 t = m_tag_copy(p, how);
443 m_tag_delete_chain(to, NULL);
447 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
449 SLIST_INSERT_AFTER(tprev, t, m_tag_link);