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 1.15 2007/10/20 10:28:44 sephe 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
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14 * notice, this list of conditions and the following disclaimer.
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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.
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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
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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
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36 * Copyright (c) 1982, 1986, 1988, 1991, 1993
37 * The Regents of the University of California. All rights reserved.
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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.
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52 * may be used to endorse or promote products derived from this software
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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
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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 MALLOC_DEFINE(M_PACKET_TAGS, "tag", "packet-attached information");
81 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
82 static struct mbuf *m_dup1 (struct mbuf *, int, int, int);
85 * ensure that [off, off + len) is contiguous on the mbuf chain "m".
86 * packet chain before "off" is kept untouched.
87 * if offp == NULL, the target will start at <retval, 0> on resulting chain.
88 * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
90 * on error return (NULL return value), original "m" will be freed.
92 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)
95 m_pulldown(struct mbuf *m, int off, int len, int *offp)
101 /* check invalid arguments. */
103 panic("m == NULL in m_pulldown()");
104 if (len > MCLBYTES) {
106 return NULL; /* impossible */
109 #ifdef PULLDOWN_DEBUG
113 for (t = m; t; t = t->m_next)
114 kprintf(" %d", t->m_len);
119 while (n != NULL && off > 0) {
125 /* be sure to point non-empty mbuf */
126 while (n != NULL && n->m_len == 0)
130 return NULL; /* mbuf chain too short */
133 sharedcluster = (m_sharecount(n) > 1);
136 * the target data is on <n, off>.
137 * if we got enough data on the mbuf "n", we're done.
139 if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster)
143 * when len <= n->m_len - off and off != 0, it is a special case.
144 * len bytes from <n, off> sits in single mbuf, but the caller does
145 * not like the starting position (off).
146 * chop the current mbuf into two pieces, set off to 0.
148 if (len <= n->m_len - off) {
149 o = m_dup1(n, off, n->m_len - off, MB_DONTWAIT);
152 return NULL; /* ENOBUFS */
155 o->m_next = n->m_next;
163 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
164 * and construct contiguous mbuf with m_len == len.
165 * note that hlen + tlen == len, and tlen > 0.
167 hlen = n->m_len - off;
171 * ensure that we have enough trailing data on mbuf chain.
172 * if not, we can do nothing about the chain.
175 for (o = n->m_next; o != NULL; o = o->m_next)
177 if (hlen + olen < len) {
179 return NULL; /* mbuf chain too short */
184 * we need to use m_copydata() to get data from <n->m_next, 0>.
186 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen &&
188 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
190 m_adj(n->m_next, tlen);
193 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen &&
195 n->m_next->m_data -= hlen;
196 n->m_next->m_len += hlen;
197 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
205 * now, we need to do the hard way. don't m_copy as there's no room
208 o = m_getl(len, MB_DONTWAIT, m->m_type, 0, NULL);
211 return NULL; /* ENOBUFS */
213 /* get hlen from <n, off> into <o, 0> */
215 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
217 /* get tlen from <n->m_next, 0> into <o, hlen> */
218 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
220 m_adj(n->m_next, tlen);
221 o->m_next = n->m_next;
227 #ifdef PULLDOWN_DEBUG
231 for (t = m; t; t = t->m_next)
232 kprintf("%c%d", t == n ? '*' : ' ', t->m_len);
233 kprintf(" (off=%d)\n", off);
242 m_dup1(struct mbuf *m, int off, int len, int wait)
248 n = m_getl(len, wait, m->m_type, m->m_flags, NULL);
251 if (off == 0 && (m->m_flags & M_PKTHDR) && !m_dup_pkthdr(n, m, wait)) {
255 m_copydata(m, off, len, mtod(n, caddr_t));
259 /* Get a packet tag structure along with specified data following. */
261 m_tag_alloc(u_int32_t cookie, int type, int len, int wait)
267 t = kmalloc(len + sizeof(struct m_tag), M_PACKET_TAGS, MBTOM(wait));
272 t->m_tag_cookie = cookie;
277 /* Free a packet tag. */
279 m_tag_free(struct m_tag *t)
281 kfree(t, M_PACKET_TAGS);
284 /* Prepend a packet tag. */
286 m_tag_prepend(struct mbuf *m, struct m_tag *t)
288 KASSERT(m && t, ("m_tag_prepend: null argument, m %p t %p", m, t));
289 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_prepend: mbuf %p non-header", m));
290 SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
293 /* Unlink a packet tag. */
295 m_tag_unlink(struct mbuf *m, struct m_tag *t)
297 KASSERT(m && t, ("m_tag_unlink: null argument, m %p t %p", m, t));
298 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_unlink: mbuf %p non-header", m));
299 SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
302 /* Unlink and free a packet tag. */
304 m_tag_delete(struct mbuf *m, struct m_tag *t)
306 KASSERT(m && t, ("m_tag_delete: null argument, m %p t %p", m, t));
307 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete: mbuf %p non-header", m));
312 /* Unlink and free a packet tag chain, starting from given tag. */
314 m_tag_delete_chain(struct mbuf *m)
318 KASSERT(m, ("m_tag_delete_chain: null mbuf"));
319 KASSERT(m->m_flags & M_PKTHDR, ("m_tag_delete_chain: mbuf %p non-header", m));
320 p = SLIST_FIRST(&m->m_pkthdr.tags);
323 while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
328 /* Find a tag, starting from a given position. */
330 m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t)
334 KASSERT(m, ("m_tag_find: null mbuf"));
336 p = SLIST_FIRST(&m->m_pkthdr.tags);
338 p = SLIST_NEXT(t, m_tag_link);
340 if (p->m_tag_cookie == cookie && p->m_tag_id == type)
342 p = SLIST_NEXT(p, m_tag_link);
347 /* Copy a single tag. */
349 m_tag_copy(struct m_tag *t, int how)
353 KASSERT(t, ("m_tag_copy: null tag"));
354 p = m_tag_alloc(t->m_tag_cookie, t->m_tag_id, t->m_tag_len, how);
357 bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */
362 * Copy two tag chains. The destination mbuf (to) loses any attached
363 * tags even if the operation fails. This should not be a problem, as
364 * m_tag_copy_chain() is typically called with a newly-allocated
368 m_tag_copy_chain(struct mbuf *to, const struct mbuf *from, int how)
370 struct m_tag *p, *t, *tprev = NULL;
373 ("m_tag_copy: null argument, to %p from %p", to, from));
374 m_tag_delete_chain(to);
375 SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
376 t = m_tag_copy(p, how);
378 m_tag_delete_chain(to);
382 SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
384 SLIST_INSERT_AFTER(tprev, t, m_tag_link);
391 /* Initialize tags on an mbuf. */
393 m_tag_init(struct mbuf *m)
395 SLIST_INIT(&m->m_pkthdr.tags);
398 /* Get first tag in chain. */
400 m_tag_first(struct mbuf *m)
402 return SLIST_FIRST(&m->m_pkthdr.tags);
405 /* Get next tag in chain. */
407 m_tag_next(struct mbuf *m, struct m_tag *t)
409 return SLIST_NEXT(t, m_tag_link);