xref: /illumos-gate/usr/src/uts/common/fs/smbsrv/smb_mbuf_util.c (revision 9498083eeaed1aacdde41369b7fa6f3b84870791)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Copyright (c) 1982, 1986, 1988, 1991, 1993
29  *	The Regents of the University of California.  All rights reserved.
30  *
31  * Redistribution and use in source and binary forms, with or without
32  * modification, are permitted provided that the following conditions
33  * are met:
34  * 1. Redistributions of source code must retain the above copyright
35  *    notice, this list of conditions and the following disclaimer.
36  * 2. Redistributions in binary form must reproduce the above copyright
37  *    notice, this list of conditions and the following disclaimer in the
38  *    documentation and/or other materials provided with the distribution.
39  * 3. All advertising materials mentioning features or use of this software
40  *    must display the following acknowledgement:
41  *	This product includes software developed by the University of
42  *	California, Berkeley and its contributors.
43  * 4. Neither the name of the University nor the names of its contributors
44  *    may be used to endorse or promote products derived from this software
45  *    without specific prior written permission.
46  *
47  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
57  * SUCH DAMAGE.
58  *
59  */
60 
61 #include <smbsrv/smb_kproto.h>
62 #include <smbsrv/smb_kstat.h>
63 
64 static kmem_cache_t	*smb_mbc_cache = NULL;
65 static kmem_cache_t	*smb_mbuf_cache = NULL;
66 static kmem_cache_t	*smb_mbufcl_cache = NULL;
67 
68 void
69 smb_mbc_init(void)
70 {
71 	if (smb_mbc_cache != NULL)
72 		return;
73 	smb_mbc_cache = kmem_cache_create(SMBSRV_KSTAT_MBC_CACHE,
74 	    sizeof (mbuf_chain_t), 8, NULL, NULL, NULL, NULL, NULL, 0);
75 
76 	smb_mbuf_cache = kmem_cache_create("smb_mbuf_cache",
77 	    sizeof (mbuf_t), 8, NULL, NULL, NULL, NULL, NULL, 0);
78 
79 	smb_mbufcl_cache = kmem_cache_create("smb_mbufcl_cache",
80 	    MCLBYTES, 8, NULL, NULL, NULL, NULL, NULL, 0);
81 }
82 
83 void
84 smb_mbc_fini(void)
85 {
86 	if (smb_mbc_cache != NULL) {
87 		kmem_cache_destroy(smb_mbc_cache);
88 		smb_mbc_cache = NULL;
89 	}
90 	if (smb_mbuf_cache != NULL) {
91 		kmem_cache_destroy(smb_mbuf_cache);
92 		smb_mbuf_cache = NULL;
93 	}
94 	if (smb_mbufcl_cache != NULL) {
95 		kmem_cache_destroy(smb_mbufcl_cache);
96 		smb_mbufcl_cache = NULL;
97 	}
98 }
99 
100 mbuf_chain_t *
101 smb_mbc_alloc(uint32_t max_bytes)
102 {
103 	mbuf_chain_t	*mbc;
104 	mbuf_t		*m;
105 
106 	mbc = kmem_cache_alloc(smb_mbc_cache, KM_SLEEP);
107 	bzero(mbc, sizeof (*mbc));
108 	mbc->mbc_magic = SMB_MBC_MAGIC;
109 
110 	if (max_bytes != 0) {
111 		MGET(m, M_WAIT, MT_DATA);
112 		m->m_len = 0;
113 		mbc->chain = m;
114 		if (max_bytes > MINCLSIZE)
115 			MCLGET(m, M_WAIT);
116 	}
117 	mbc->max_bytes = max_bytes;
118 	return (mbc);
119 }
120 
121 void
122 smb_mbc_free(mbuf_chain_t *mbc)
123 {
124 	SMB_MBC_VALID(mbc);
125 
126 	m_freem(mbc->chain);
127 	mbc->chain = NULL;
128 	mbc->mbc_magic = 0;
129 	kmem_cache_free(smb_mbc_cache, mbc);
130 }
131 
132 /*
133  * smb_mbuf_get
134  *
135  * Allocate mbufs to hold the amount of data specified.
136  * A pointer to the head of the mbuf list is returned.
137  */
138 struct mbuf *
139 smb_mbuf_get(uchar_t *buf, int nbytes)
140 {
141 	struct mbuf *mhead = 0;
142 	struct mbuf *m = 0;
143 	int count;
144 	int offset = 0;
145 
146 	while (nbytes) {
147 		count = (nbytes > MCLBYTES) ? MCLBYTES : nbytes;
148 		nbytes -= count;
149 
150 		if (mhead == 0) {
151 			MGET(mhead, M_WAIT, MT_DATA);
152 			m = mhead;
153 		} else {
154 			MGET(m->m_next, M_WAIT, MT_DATA);
155 			m = m->m_next;
156 		}
157 
158 		if (count > MLEN) {
159 			MCLGET(m, M_WAIT);
160 		}
161 
162 		m->m_len = count;
163 		bcopy(buf + offset, m->m_data, count);
164 		offset += count;
165 	}
166 	return (mhead);
167 }
168 
169 static int
170 smb_mbuf_kmem_ref(void *p, uint_t sz, int incr)
171 {
172 	if (incr < 0)
173 		kmem_free(p, sz);
174 	return (0);
175 }
176 
177 /*
178  * Allocate enough mbufs to accommodate the residual count in uio,
179  * and setup the uio_iov to point to them.
180  *
181  * This is used by the various SMB read code paths.  That code is
182  * going to do a disk read into this buffer, so we'd like it to be
183  * large and contiguous.  Use an external (M_EXT) buffer.
184  */
185 struct mbuf *
186 smb_mbuf_allocate(struct uio *uio)
187 {
188 	mbuf_t	*m = 0;
189 	int	len = uio->uio_resid;
190 
191 	MGET(m, M_WAIT, MT_DATA);
192 	if (len > MCLBYTES) {
193 		/* Like MCLGET(), but bigger buf. */
194 		m->m_ext.ext_buf = kmem_zalloc(len, KM_SLEEP);
195 		m->m_data = m->m_ext.ext_buf;
196 		m->m_flags |= M_EXT;
197 		m->m_ext.ext_size = len;
198 		m->m_ext.ext_ref = smb_mbuf_kmem_ref;
199 	} else if (len > MLEN) {
200 		/* Use the kmem cache. */
201 		MCLGET(m, M_WAIT);
202 	}
203 	m->m_len = len;
204 
205 	uio->uio_iov->iov_base = m->m_data;
206 	uio->uio_iov->iov_len = m->m_len;
207 	uio->uio_iovcnt = 1;
208 
209 	return (m);
210 }
211 
212 /*
213  * Trim an mbuf chain to nbytes.
214  */
215 void
216 smb_mbuf_trim(struct mbuf *mhead, int nbytes)
217 {
218 	struct mbuf	*m = mhead;
219 
220 	while (m != 0) {
221 		if (nbytes <= m->m_len) {
222 			m->m_len = nbytes;
223 			if (m->m_next != 0) {
224 				m_freem(m->m_next);
225 				m->m_next = 0;
226 			}
227 			break;
228 		}
229 		nbytes -= m->m_len;
230 		m = m->m_next;
231 	}
232 }
233 
234 int
235 MBC_LENGTH(struct mbuf_chain *MBC)
236 {
237 	struct mbuf	*m = (MBC)->chain;
238 	int		used = 0;
239 
240 	while (m != 0) {
241 		used += m->m_len;
242 		m = m->m_next;
243 	}
244 	return (used);
245 }
246 
247 int
248 MBC_MAXBYTES(struct mbuf_chain *MBC)
249 {
250 	return (MBC->max_bytes);
251 }
252 
253 void
254 MBC_SETUP(struct mbuf_chain *MBC, uint32_t max_bytes)
255 {
256 	bzero((MBC), sizeof (struct mbuf_chain));
257 	(MBC)->max_bytes = max_bytes;
258 }
259 
260 void
261 MBC_INIT(struct mbuf_chain *MBC, uint32_t max_bytes)
262 {
263 	struct mbuf *m;
264 
265 	bzero((MBC), sizeof (struct mbuf_chain));
266 
267 	if (max_bytes != 0) {
268 		MGET(m, M_WAIT, MT_DATA);
269 		m->m_len = 0;
270 		(MBC)->chain = m;
271 		if (max_bytes > MINCLSIZE)
272 			MCLGET(m, M_WAIT);
273 	}
274 	(MBC)->max_bytes = max_bytes;
275 }
276 
277 void
278 MBC_FLUSH(struct mbuf_chain *MBC)
279 {
280 	extern void	m_freem(struct mbuf *);
281 	struct mbuf	*m;
282 
283 	while ((m = (MBC)->chain) != 0) {
284 		(MBC)->chain = m->m_nextpkt;
285 		m->m_nextpkt = 0;
286 		m_freem(m);
287 	}
288 	MBC_SETUP(MBC, (MBC)->max_bytes);
289 }
290 
291 void
292 MBC_ATTACH_MBUF(struct mbuf_chain *MBC, struct mbuf *MBUF)
293 {
294 	if (MBC->chain != 0)
295 		MBC_FLUSH(MBC);
296 
297 	(MBC)->chain_offset = 0;
298 	(MBC)->chain = (MBUF);
299 }
300 
301 void
302 MBC_APPEND_MBUF(struct mbuf_chain *MBC, struct mbuf *MBUF)
303 {
304 	struct mbuf	*m;
305 
306 	if ((MBC)->chain == 0) {
307 		(MBC)->chain = (MBUF);
308 	} else {
309 		m = (MBC)->chain;
310 		while (m->m_next != 0)
311 			m = m->m_next;
312 		m->m_next = (MBUF);
313 	}
314 }
315 
316 static int /*ARGSUSED*/
317 mclrefnoop(caddr_t p, int size, int adj)
318 {
319 	return (0);
320 }
321 
322 void
323 MBC_ATTACH_BUF(struct mbuf_chain *MBC, unsigned char *BUF, int LEN)
324 {
325 	MGET((MBC)->chain, M_WAIT, MT_DATA);
326 	(MBC)->chain_offset = 0;
327 	(MBC)->chain->m_flags |= M_EXT;
328 	(MBC)->chain->m_data = (caddr_t)(BUF);
329 	(MBC)->chain->m_ext.ext_buf = (caddr_t)(BUF);
330 	(MBC)->chain->m_len = (LEN);
331 	(MBC)->chain->m_ext.ext_size = (LEN);
332 	(MBC)->chain->m_ext.ext_ref = mclrefnoop;
333 	(MBC)->max_bytes = (LEN);
334 }
335 
336 
337 int
338 MBC_SHADOW_CHAIN(struct mbuf_chain *submbc, struct mbuf_chain *mbc,
339     int off, int len)
340 {
341 	int x = off + len;
342 
343 	if (off < 0 || len < 0 || x < 0 ||
344 	    off > mbc->max_bytes || x > mbc->max_bytes)
345 		return (EMSGSIZE);
346 
347 	*submbc = *mbc;
348 	submbc->chain_offset = off;
349 	submbc->max_bytes = x;
350 	submbc->shadow_of = mbc;
351 	return (0);
352 }
353 
354 /*
355  * Free a single mbuf structure.  Calls m->m_ext.ext_ref() to free any
356  * associated external buffers if present (indicated by m->m_flags & M_EXT)
357  */
358 struct mbuf *
359 m_free(struct mbuf *m)
360 {
361 	struct mbuf *n;
362 
363 	MFREE(m, n);
364 	return (n);
365 }
366 
367 /*
368  * Free a list of mbufs.  Each mbuf in the list is freed similarly to m_free.
369  */
370 void
371 m_freem(struct mbuf *m)
372 {
373 	struct mbuf *n;
374 
375 	if (m == NULL)
376 		return;
377 	/*
378 	 * Lint doesn't like the m = n assignment at the close of the loop
379 	 * but it is correct.  MFREE assigns n = (m)->m_next so the loop
380 	 * is effectively assigning m = (m)->m_next then exiting when
381 	 * m == NULL
382 	 */
383 	do {
384 		MFREE(m, n);
385 	} while ((m = n) != 0);
386 }
387 
388 /*
389  * Mbuffer utility routines.
390  */
391 
392 mbuf_t *
393 smb_mbuf_alloc(void)
394 {
395 	mbuf_t *m;
396 
397 	m = kmem_cache_alloc(smb_mbuf_cache, KM_SLEEP);
398 	bzero(m, sizeof (*m));
399 	return (m);
400 }
401 
402 void
403 smb_mbuf_free(mbuf_t *m)
404 {
405 	kmem_cache_free(smb_mbuf_cache, m);
406 }
407 
408 void *
409 smb_mbufcl_alloc(void)
410 {
411 	void *p;
412 
413 	p = kmem_cache_alloc(smb_mbufcl_cache, KM_SLEEP);
414 	bzero(p, MCLBYTES);
415 	return (p);
416 }
417 
418 void
419 smb_mbufcl_free(void *p)
420 {
421 	kmem_cache_free(smb_mbufcl_cache, p);
422 }
423 
424 int
425 smb_mbufcl_ref(void *p, uint_t sz, int incr)
426 {
427 	ASSERT3S(sz, ==, MCLBYTES);
428 	if (incr < 0)
429 		kmem_cache_free(smb_mbufcl_cache, p);
430 	return (0);
431 }
432