1 /* $FreeBSD: src/sys/kern/uipc_mbuf2.c,v 1.2.2.5 2003/01/23 21:06:44 sam Exp $ */
2 /* $DragonFly: src/sys/kern/uipc_mbuf2.c,v 1.4 2003/08/26 21:09:02 rob Exp $ */
3 /* $KAME: uipc_mbuf2.c,v 1.31 2001/11/28 11:08:53 itojun Exp $ */
4 /* $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $ */
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
36 * Copyright (c) 1982, 1986, 1988, 1991, 1993
37 * The Regents of the University of California. All rights reserved.
39 * Redistribution and use in source and binary forms, with or without
40 * modification, are permitted provided that the following conditions
42 * 1. Redistributions of source code must retain the above copyright
43 * notice, this list of conditions and the following disclaimer.
44 * 2. Redistributions in binary form must reproduce the above copyright
45 * notice, this list of conditions and the following disclaimer in the
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49 * This product includes software developed by the University of
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51 * 4. Neither the name of the University nor the names of its contributors
52 * may be used to endorse or promote products derived from this software
53 * without specific prior written permission.
55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
67 * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95
70 /*#define PULLDOWN_DEBUG*/
72 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/kernel.h>
76 #include <sys/malloc.h>
79 #define M_SHAREDCLUSTER(m) \
80 (((m)->m_flags & M_EXT) != 0 && \
81 ((m)->m_ext.ext_free || mclrefcnt[mtocl((m)->m_ext.ext_buf)] > 1))
83 MALLOC_DEFINE(M_PACKET_TAGS, "tag", "packet-attached information");
85 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
86 static struct mbuf *m_dup1 (struct mbuf *, int, int, int);
89 * ensure that [off, off + len) is contiguous on the mbuf chain "m".
90 * packet chain before "off" is kept untouched.
91 * if offp == NULL, the target will start at <retval, 0> on resulting chain.
92 * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
94 * on error return (NULL return value), original "m" will be freed.
96 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)
99 m_pulldown(m, off, len, offp)
105 int hlen, tlen, olen;
108 /* check invalid arguments. */
110 panic("m == NULL in m_pulldown()");
111 if (len > MCLBYTES) {
113 return NULL; /* impossible */
116 #ifdef PULLDOWN_DEBUG
120 for (t = m; t; t = t->m_next)
121 printf(" %d", t->m_len);
126 while (n != NULL && off > 0) {
132 /* be sure to point non-empty mbuf */
133 while (n != NULL && n->m_len == 0)
137 return NULL; /* mbuf chain too short */
140 sharedcluster = M_SHAREDCLUSTER(n);
143 * the target data is on <n, off>.
144 * if we got enough data on the mbuf "n", we're done.
146 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster)
150 * when len <= n->m_len - off and off != 0, it is a special case.
151 * len bytes from <n, off> sits in single mbuf, but the caller does
152 * not like the starting position (off).
153 * chop the current mbuf into two pieces, set off to 0.
155 if (len <= n->m_len - off) {
156 o = m_dup1(n, off, n->m_len - off, M_DONTWAIT);
159 return NULL; /* ENOBUFS */
162 o->m_next = n->m_next;
170 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
171 * and construct contiguous mbuf with m_len == len.
172 * note that hlen + tlen == len, and tlen > 0.
174 hlen = n->m_len - off;
178 * ensure that we have enough trailing data on mbuf chain.
179 * if not, we can do nothing about the chain.
182 for (o = n->m_next; o != NULL; o = o->m_next)
184 if (hlen + olen < len) {
186 return NULL; /* mbuf chain too short */
191 * we need to use m_copydata() to get data from <n->m_next, 0>.
193 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen &&
195 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
197 m_adj(n->m_next, tlen);
200 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen &&
202 n->m_next->m_data -= hlen;
203 n->m_next->m_len += hlen;
204 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
212 * now, we need to do the hard way. don't m_copy as there's no room
215 MGET(o, M_DONTWAIT, m->m_type);
216 if (o && len > MLEN) {
217 MCLGET(o, M_DONTWAIT);
218 if ((o->m_flags & M_EXT) == 0) {
225 return NULL; /* ENOBUFS */
227 /* get hlen from <n, off> into <o, 0> */
229 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
231 /* get tlen from <n->m_next, 0> into <o, hlen> */
232 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
234 m_adj(n->m_next, tlen);
235 o->m_next = n->m_next;
241 #ifdef PULLDOWN_DEBUG
245 for (t = m; t; t = t->m_next)
246 printf("%c%d", t == n ? '*' : ' ', t->m_len);
247 printf(" (off=%d)\n", off);
256 m_dup1(m, off, len, wait)
268 if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {
270 MGETHDR(n, wait, m->m_type);
274 MGET(n, wait, m->m_type);
279 if ((n->m_flags & M_EXT) == 0) {
287 if (copyhdr && !m_dup_pkthdr(n, m, wait)) {
291 m_copydata(m, off, len, mtod(n, caddr_t));
295 /* Get a packet tag structure along with specified data following. */
297 m_tag_alloc(u_int32_t cookie, int type, int len, int wait)
303 t = malloc(len + sizeof(struct m_tag), M_PACKET_TAGS, wait);
308 t->m_tag_cookie = cookie;
313 /* Free a packet tag. */
315 m_tag_free(struct m_tag *t)
317 free(t, M_PACKET_TAGS);
320 /* Prepend a packet tag. */
322 m_tag_prepend(struct mbuf *m, struct m_tag *t)
324 KASSERT(m && t, ("m_tag_prepend: null argument, m %p t %p", m, t));
325 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
328 /* Unlink a packet tag. */
330 m_tag_unlink(struct mbuf *m, struct m_tag *t)
332 KASSERT(m && t, ("m_tag_unlink: null argument, m %p t %p", m, t));
333 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
336 /* Unlink and free a packet tag. */
338 m_tag_delete(struct mbuf *m, struct m_tag *t)
340 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t));
345 /* Unlink and free a packet tag chain, starting from given tag. */
347 m_tag_delete_chain(struct mbuf *m, struct m_tag *t)
351 KASSERT(m, ("m_tag_delete_chain: null mbuf"));
355 p = SLIST_FIRST(&m->m_pkthdr.tags);
358 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
363 /* Find a tag, starting from a given position. */
365 m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t)
369 KASSERT(m, ("m_tag_find: null mbuf"));
371 p = SLIST_FIRST(&m->m_pkthdr.tags);
373 p = SLIST_NEXT(t, m_tag_link);
375 if (p->m_tag_cookie == cookie && p->m_tag_id == type)
377 p = SLIST_NEXT(p, m_tag_link);
382 /* Copy a single tag. */
384 m_tag_copy(struct m_tag *t, int how)
388 KASSERT(t, ("m_tag_copy: null tag"));
389 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how);
392 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */
397 * Copy two tag chains. The destination mbuf (to) loses any attached
398 * tags even if the operation fails. This should not be a problem, as
399 * m_tag_copy_chain() is typically called with a newly-allocated
403 m_tag_copy_chain(struct mbuf *to, const struct mbuf *from, int how)
405 struct m_tag *p, *t, *tprev = NULL;
408 ("m_tag_copy: null argument, to %p from %p", to, from));
409 m_tag_delete_chain(to, NULL);
410 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
411 t = m_tag_copy(p, how);
413 m_tag_delete_chain(to, NULL);
417 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
419 SLIST_INSERT_AFTER(tprev, t, m_tag_link);
426 /* Initialize tags on an mbuf. */
428 m_tag_init(struct mbuf *m)
430 SLIST_INIT(&m->m_pkthdr.tags);
433 /* Get first tag in chain. */
435 m_tag_first(struct mbuf *m)
437 return SLIST_FIRST(&m->m_pkthdr.tags);
440 /* Get next tag in chain. */
442 m_tag_next(struct mbuf *m, struct m_tag *t)
444 return SLIST_NEXT(t, m_tag_link);