1/*	$OpenBSD: uipc_mbuf2.c,v 1.45 2020/12/12 11:48:54 jan Exp $	*/
2/*	$KAME: uipc_mbuf2.c,v 1.29 2001/02/14 13:42:10 itojun Exp $	*/
3/*	$NetBSD: uipc_mbuf.c,v 1.40 1999/04/01 00:23:25 thorpej Exp $	*/
4
5/*
6 * Copyright (C) 1999 WIDE Project.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
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.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34/*
35 * Copyright (c) 1982, 1986, 1988, 1991, 1993
36 *	The Regents of the University of California.  All rights reserved.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions
40 * are met:
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.
49 *
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
60 * SUCH DAMAGE.
61 *
62 *	@(#)uipc_mbuf.c	8.4 (Berkeley) 2/14/95
63 */
64
65#include <sys/param.h>
66#include <sys/systm.h>
67#include <sys/malloc.h>
68#include <sys/pool.h>
69#include <sys/mbuf.h>
70
71extern struct pool mtagpool;
72
73/* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
74static struct mbuf *m_dup1(struct mbuf *, int, int, int);
75
76/*
77 * ensure that [off, off + len] is contiguous on the mbuf chain "m".
78 * packet chain before "off" is kept untouched.
79 * if offp == NULL, the target will start at <retval, 0> on resulting chain.
80 * if offp != NULL, the target will start at <retval, *offp> on resulting chain.
81 *
82 * on error return (NULL return value), original "m" will be freed.
83 *
84 * XXX m_trailingspace/m_leadingspace on shared cluster (sharedcluster)
85 */
86struct mbuf *
87m_pulldown(struct mbuf *m, int off, int len, int *offp)
88{
89	struct mbuf *n, *o;
90	int hlen, tlen, olen;
91	int sharedcluster;
92
93	/* check invalid arguments. */
94	if (m == NULL)
95		panic("m == NULL in m_pulldown()");
96
97	if ((n = m_getptr(m, off, &off)) == NULL) {
98		m_freem(m);
99		return (NULL);	/* mbuf chain too short */
100	}
101
102	sharedcluster = M_READONLY(n);
103
104	/*
105	 * the target data is on <n, off>.
106	 * if we got enough data on the mbuf "n", we're done.
107	 */
108	if ((off == 0 || offp) && len <= n->m_len - off && !sharedcluster)
109		goto ok;
110
111	/*
112	 * when len <= n->m_len - off and off != 0, it is a special case.
113	 * len bytes from <n, off> sits in single mbuf, but the caller does
114	 * not like the starting position (off).
115	 * chop the current mbuf into two pieces, set off to 0.
116	 */
117	if (len <= n->m_len - off) {
118		struct mbuf *mlast;
119
120		o = m_dup1(n, off, n->m_len - off, M_DONTWAIT);
121		if (o == NULL) {
122			m_freem(m);
123			return (NULL);	/* ENOBUFS */
124		}
125		for (mlast = o; mlast->m_next != NULL; mlast = mlast->m_next)
126			;
127		n->m_len = off;
128		mlast->m_next = n->m_next;
129		n->m_next = o;
130		n = o;
131		off = 0;
132		goto ok;
133	}
134
135	/*
136	 * we need to take hlen from <n, off> and tlen from <n->m_next, 0>,
137	 * and construct contiguous mbuf with m_len == len.
138	 * note that hlen + tlen == len, and tlen > 0.
139	 */
140	hlen = n->m_len - off;
141	tlen = len - hlen;
142
143	/*
144	 * ensure that we have enough trailing data on mbuf chain.
145	 * if not, we can do nothing about the chain.
146	 */
147	olen = 0;
148	for (o = n->m_next; o != NULL; o = o->m_next)
149		olen += o->m_len;
150	if (hlen + olen < len) {
151		m_freem(m);
152		return (NULL);	/* mbuf chain too short */
153	}
154
155	/*
156	 * easy cases first.
157	 * we need to use m_copydata() to get data from <n->m_next, 0>.
158	 */
159	if ((off == 0 || offp) && m_trailingspace(n) >= tlen &&
160	    !sharedcluster) {
161		m_copydata(n->m_next, 0, tlen, mtod(n, caddr_t) + n->m_len);
162		n->m_len += tlen;
163		m_adj(n->m_next, tlen);
164		goto ok;
165	}
166	if ((off == 0 || offp) && m_leadingspace(n->m_next) >= hlen &&
167	    !sharedcluster && n->m_next->m_len >= tlen) {
168		n->m_next->m_data -= hlen;
169		n->m_next->m_len += hlen;
170		memmove(mtod(n->m_next, caddr_t), mtod(n, caddr_t) + off, hlen);
171		n->m_len -= hlen;
172		n = n->m_next;
173		off = 0;
174		goto ok;
175	}
176
177	/*
178	 * now, we need to do the hard way.  don't m_copym as there's no room
179	 * on both ends.
180	 */
181	if (len > MAXMCLBYTES) {
182		m_freem(m);
183		return (NULL);
184	}
185	MGET(o, M_DONTWAIT, m->m_type);
186	if (o && len > MLEN) {
187		MCLGETL(o, M_DONTWAIT, len);
188		if ((o->m_flags & M_EXT) == 0) {
189			m_free(o);
190			o = NULL;
191		}
192	}
193	if (!o) {
194		m_freem(m);
195		return (NULL);	/* ENOBUFS */
196	}
197	/* get hlen from <n, off> into <o, 0> */
198	o->m_len = hlen;
199	memmove(mtod(o, caddr_t), mtod(n, caddr_t) + off, hlen);
200	n->m_len -= hlen;
201	/* get tlen from <n->m_next, 0> into <o, hlen> */
202	m_copydata(n->m_next, 0, tlen, mtod(o, caddr_t) + o->m_len);
203	o->m_len += tlen;
204	m_adj(n->m_next, tlen);
205	o->m_next = n->m_next;
206	n->m_next = o;
207	n = o;
208	off = 0;
209
210ok:
211	if (offp)
212		*offp = off;
213	return (n);
214}
215
216static struct mbuf *
217m_dup1(struct mbuf *m, int off, int len, int wait)
218{
219	struct mbuf *n;
220	int l;
221
222	if (len > MAXMCLBYTES)
223		return (NULL);
224	if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {
225		MGETHDR(n, wait, m->m_type);
226		if (n == NULL)
227			return (NULL);
228		if (m_dup_pkthdr(n, m, wait)) {
229			m_free(n);
230			return (NULL);
231		}
232		l = MHLEN;
233	} else {
234		MGET(n, wait, m->m_type);
235		l = MLEN;
236	}
237	if (n && len > l) {
238		MCLGETL(n, wait, len);
239		if ((n->m_flags & M_EXT) == 0) {
240			m_free(n);
241			n = NULL;
242		}
243	}
244	if (!n)
245		return (NULL);
246
247	m_copydata(m, off, len, mtod(n, caddr_t));
248	n->m_len = len;
249
250	return (n);
251}
252
253/* Get a packet tag structure along with specified data following. */
254struct m_tag *
255m_tag_get(int type, int len, int wait)
256{
257	struct m_tag *t;
258
259	if (len < 0)
260		return (NULL);
261	if (len > PACKET_TAG_MAXSIZE)
262		panic("requested tag size for pool %#x is too big", type);
263	t = pool_get(&mtagpool, wait == M_WAITOK ? PR_WAITOK : PR_NOWAIT);
264	if (t == NULL)
265		return (NULL);
266	t->m_tag_id = type;
267	t->m_tag_len = len;
268	return (t);
269}
270
271/* Prepend a packet tag. */
272void
273m_tag_prepend(struct mbuf *m, struct m_tag *t)
274{
275	SLIST_INSERT_HEAD(&m->m_pkthdr.ph_tags, t, m_tag_link);
276	m->m_pkthdr.ph_tagsset |= t->m_tag_id;
277}
278
279/* Unlink and free a packet tag. */
280void
281m_tag_delete(struct mbuf *m, struct m_tag *t)
282{
283	u_int32_t	 ph_tagsset = 0;
284	struct m_tag	*p;
285
286	SLIST_REMOVE(&m->m_pkthdr.ph_tags, t, m_tag, m_tag_link);
287	pool_put(&mtagpool, t);
288
289	SLIST_FOREACH(p, &m->m_pkthdr.ph_tags, m_tag_link)
290		ph_tagsset |= p->m_tag_id;
291	m->m_pkthdr.ph_tagsset = ph_tagsset;
292
293}
294
295/* Unlink and free a packet tag chain. */
296void
297m_tag_delete_chain(struct mbuf *m)
298{
299	struct m_tag *p;
300
301	while ((p = SLIST_FIRST(&m->m_pkthdr.ph_tags)) != NULL) {
302		SLIST_REMOVE_HEAD(&m->m_pkthdr.ph_tags, m_tag_link);
303		pool_put(&mtagpool, p);
304	}
305	m->m_pkthdr.ph_tagsset = 0;
306}
307
308/* Find a tag, starting from a given position. */
309struct m_tag *
310m_tag_find(struct mbuf *m, int type, struct m_tag *t)
311{
312	struct m_tag *p;
313
314	if (!(m->m_pkthdr.ph_tagsset & type))
315		return (NULL);
316
317	if (t == NULL)
318		p = SLIST_FIRST(&m->m_pkthdr.ph_tags);
319	else
320		p = SLIST_NEXT(t, m_tag_link);
321	while (p != NULL) {
322		if (p->m_tag_id == type)
323			return (p);
324		p = SLIST_NEXT(p, m_tag_link);
325	}
326	return (NULL);
327}
328
329/* Copy a single tag. */
330struct m_tag *
331m_tag_copy(struct m_tag *t, int wait)
332{
333	struct m_tag *p;
334
335	p = m_tag_get(t->m_tag_id, t->m_tag_len, wait);
336	if (p == NULL)
337		return (NULL);
338	memcpy(p + 1, t + 1, t->m_tag_len); /* Copy the data */
339	return (p);
340}
341
342/*
343 * Copy two tag chains. The destination mbuf (to) loses any attached
344 * tags even if the operation fails. This should not be a problem, as
345 * m_tag_copy_chain() is typically called with a newly-allocated
346 * destination mbuf.
347 */
348int
349m_tag_copy_chain(struct mbuf *to, struct mbuf *from, int wait)
350{
351	struct m_tag *p, *t, *tprev = NULL;
352
353	m_tag_delete_chain(to);
354	SLIST_FOREACH(p, &from->m_pkthdr.ph_tags, m_tag_link) {
355		t = m_tag_copy(p, wait);
356		if (t == NULL) {
357			m_tag_delete_chain(to);
358			return (ENOBUFS);
359		}
360		if (tprev == NULL)
361			SLIST_INSERT_HEAD(&to->m_pkthdr.ph_tags, t, m_tag_link);
362		else
363			SLIST_INSERT_AFTER(tprev, t, m_tag_link);
364		tprev = t;
365		to->m_pkthdr.ph_tagsset |= t->m_tag_id;
366	}
367	return (0);
368}
369
370/* Initialize tags on an mbuf. */
371void
372m_tag_init(struct mbuf *m)
373{
374	SLIST_INIT(&m->m_pkthdr.ph_tags);
375}
376
377/* Get first tag in chain. */
378struct m_tag *
379m_tag_first(struct mbuf *m)
380{
381	return (SLIST_FIRST(&m->m_pkthdr.ph_tags));
382}
383
384/* Get next tag in chain. */
385struct m_tag *
386m_tag_next(struct mbuf *m, struct m_tag *t)
387{
388	return (SLIST_NEXT(t, m_tag_link));
389}
390