2 /* $KAME: uipc_mbuf2.c,v 1.15 2000/02/22 14:01:37 itojun Exp $ */
3 /* $NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $ */
6 * Copyright (C) 1999 WIDE Project.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the project nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
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22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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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.
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44 * notice, this list of conditions and the following disclaimer in the
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50 * 4. Neither the name of the University nor the names of its contributors
51 * may be used to endorse or promote products derived from this software
52 * without specific prior written permission.
54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
66 * @(#)uipc_mbuf.c 8.4 (Berkeley) 2/14/95
69 /*#define PULLDOWN_DEBUG*/
71 #include <sys/param.h>
72 #include <sys/systm.h>
74 #include <sys/malloc.h>
78 * ensure that [off, off + len) is contiguous on the mbuf chain "m".
79 * packet chain before "off" is kept untouched.
80 * if offp == NULL, the target will start at <retval, 0> on resulting chain.
81 * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
83 * on error return (NULL return value), original "m" will be freed.
85 * XXX M_TRAILINGSPACE/M_LEADINGSPACE on shared cluster (sharedcluster)
88 m_pulldown(m, off, len, offp)
97 /* check invalid arguments. */
99 panic("m == NULL in m_pulldown()");
100 if (len > MCLBYTES) {
102 return NULL; /* impossible */
105 #ifdef PULLDOWN_DEBUG
109 for (t = m; t; t = t->m_next)
110 printf(" %d", t->m_len);
115 while (n != NULL && off > 0) {
121 /* be sure to point non-empty mbuf */
122 while (n != NULL && n->m_len == 0)
126 return NULL; /* mbuf chain too short */
130 * the target data is on <n, off>.
131 * if we got enough data on the mbuf "n", we're done.
133 if ((off == 0 || offp) && len <= n->m_len - off)
137 * when len < n->m_len - off and off != 0, it is a special case.
138 * len bytes from <n, off> sits in single mbuf, but the caller does
139 * not like the starting position (off).
140 * chop the current mbuf into two pieces, set off to 0.
142 if (len < n->m_len - off) {
143 o = m_copym(n, off, n->m_len - off, M_DONTWAIT);
146 return NULL; /* ENOBUFS */
149 o->m_next = n->m_next;
157 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
158 * and construct contiguous mbuf with m_len == len.
159 * note that hlen + tlen == len, and tlen > 0.
161 hlen = n->m_len - off;
165 * ensure that we have enough trailing data on mbuf chain.
166 * if not, we can do nothing about the chain.
169 for (o = n->m_next; o != NULL; o = o->m_next)
171 if (hlen + olen < len) {
173 return NULL; /* mbuf chain too short */
178 * we need to use m_copydata() to get data from <n->m_next, 0>.
180 if ((n->m_flags & M_EXT) == 0)
183 if (n->m_ext.ext_free)
185 else if (mclrefcnt[mtocl(n->m_ext.ext_buf)] > 1)
190 if ((off == 0 || offp) && M_TRAILINGSPACE(n) >= tlen
192 m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
194 m_adj(n->m_next, tlen);
197 if ((off == 0 || offp) && M_LEADINGSPACE(n->m_next) >= hlen
199 n->m_next->m_data -= hlen;
200 n->m_next->m_len += hlen;
201 bcopy(mtod(n, caddr_t) + off, mtod(n->m_next, caddr_t), hlen);
209 * now, we need to do the hard way. don't m_copy as there's no room
212 MGET(o, M_DONTWAIT, m->m_type);
215 return NULL; /* ENOBUFS */
217 if (len > MHLEN) { /* use MHLEN just for safety */
218 MCLGET(o, M_DONTWAIT);
219 if ((o->m_flags & M_EXT) == 0) {
222 return NULL; /* ENOBUFS */
225 /* get hlen from <n, off> into <o, 0> */
227 bcopy(mtod(n, caddr_t) + off, mtod(o, caddr_t), hlen);
229 /* get tlen from <n->m_next, 0> into <o, hlen> */
230 m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
232 m_adj(n->m_next, tlen);
233 o->m_next = n->m_next;
239 #ifdef PULLDOWN_DEBUG
243 for (t = m; t; t = t->m_next)
244 printf("%c%d", t == n ? '*' : ' ', t->m_len);
245 printf(" (off=%d)\n", off);
254 * pkthdr.aux chain manipulation.
255 * we don't allow clusters at this moment.
258 m_aux_add(m, af, type)
265 if ((m->m_flags & M_PKTHDR) == 0)
268 n = m_aux_find(m, af, type);
272 MGET(n, M_DONTWAIT, m->m_type);
276 t = mtod(n, struct mauxtag *);
279 n->m_data += sizeof(struct mauxtag);
281 n->m_next = m->m_pkthdr.aux;
287 m_aux_find(m, af, type)
294 if ((m->m_flags & M_PKTHDR) == 0)
297 for (n = m->m_pkthdr.aux; n; n = n->m_next) {
298 t = (struct mauxtag *)n->m_dat;
299 if (t->af == af && t->type == type)
306 m_aux_delete(m, victim)
310 struct mbuf *n, *prev, *next;
313 if ((m->m_flags & M_PKTHDR) == 0)
319 t = (struct mauxtag *)n->m_dat;
323 prev->m_next = n->m_next;
325 m->m_pkthdr.aux = n->m_next;