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
71 extern struct pool mtagpool;
72
73 /* can't call it m_dup(), as freebsd[34] uses m_dup() with different arg */
74 static 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 */
86 struct mbuf *
m_pulldown(struct mbuf * m,int off,int len,int * offp)87 m_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
210 ok:
211 if (offp)
212 *offp = off;
213 return (n);
214 }
215
216 static struct mbuf *
m_dup1(struct mbuf * m,int off,int len,int wait)217 m_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. */
254 struct m_tag *
m_tag_get(int type,int len,int wait)255 m_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. */
272 void
m_tag_prepend(struct mbuf * m,struct m_tag * t)273 m_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. */
280 void
m_tag_delete(struct mbuf * m,struct m_tag * t)281 m_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. */
296 void
m_tag_delete_chain(struct mbuf * m)297 m_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. */
309 struct m_tag *
m_tag_find(struct mbuf * m,int type,struct m_tag * t)310 m_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. */
330 struct m_tag *
m_tag_copy(struct m_tag * t,int wait)331 m_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 */
348 int
m_tag_copy_chain(struct mbuf * to,struct mbuf * from,int wait)349 m_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. */
371 void
m_tag_init(struct mbuf * m)372 m_tag_init(struct mbuf *m)
373 {
374 SLIST_INIT(&m->m_pkthdr.ph_tags);
375 }
376
377 /* Get first tag in chain. */
378 struct m_tag *
m_tag_first(struct mbuf * m)379 m_tag_first(struct mbuf *m)
380 {
381 return (SLIST_FIRST(&m->m_pkthdr.ph_tags));
382 }
383
384 /* Get next tag in chain. */
385 struct m_tag *
m_tag_next(struct mbuf * m,struct m_tag * t)386 m_tag_next(struct mbuf *m, struct m_tag *t)
387 {
388 return (SLIST_NEXT(t, m_tag_link));
389 }
390