xref: /freebsd/sys/kern/subr_mchain.c (revision 74bf4e164ba5851606a27d4feff27717452583e5)
1 /*
2  * Copyright (c) 2000, 2001 Boris Popov
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the author nor the names of any co-contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/endian.h>
36 #include <sys/errno.h>
37 #include <sys/mbuf.h>
38 #include <sys/module.h>
39 #include <sys/uio.h>
40 
41 #include <sys/mchain.h>
42 
43 MODULE_VERSION(libmchain, 1);
44 
45 #define MBERROR(format, ...) printf("%s(%d): "format, __func__ , \
46 				    __LINE__ , ## __VA_ARGS__)
47 
48 #define MBPANIC(format, ...) printf("%s(%d): "format, __func__ , \
49 				    __LINE__ , ## __VA_ARGS__)
50 
51 /*
52  * Various helper functions
53  */
54 int
55 mb_init(struct mbchain *mbp)
56 {
57 	struct mbuf *m;
58 
59 	m = m_gethdr(M_TRYWAIT, MT_DATA);
60 	if (m == NULL)
61 		return ENOBUFS;
62 	m->m_len = 0;
63 	mb_initm(mbp, m);
64 	return 0;
65 }
66 
67 void
68 mb_initm(struct mbchain *mbp, struct mbuf *m)
69 {
70 	bzero(mbp, sizeof(*mbp));
71 	mbp->mb_top = mbp->mb_cur = m;
72 	mbp->mb_mleft = M_TRAILINGSPACE(m);
73 }
74 
75 void
76 mb_done(struct mbchain *mbp)
77 {
78 	if (mbp->mb_top) {
79 		m_freem(mbp->mb_top);
80 		mbp->mb_top = NULL;
81 	}
82 }
83 
84 struct mbuf *
85 mb_detach(struct mbchain *mbp)
86 {
87 	struct mbuf *m;
88 
89 	m = mbp->mb_top;
90 	mbp->mb_top = NULL;
91 	return m;
92 }
93 
94 int
95 mb_fixhdr(struct mbchain *mbp)
96 {
97 	return mbp->mb_top->m_pkthdr.len = m_fixhdr(mbp->mb_top);
98 }
99 
100 /*
101  * Check if object of size 'size' fit to the current position and
102  * allocate new mbuf if not. Advance pointers and increase length of mbuf(s).
103  * Return pointer to the object placeholder or NULL if any error occured.
104  * Note: size should be <= MLEN
105  */
106 caddr_t
107 mb_reserve(struct mbchain *mbp, int size)
108 {
109 	struct mbuf *m, *mn;
110 	caddr_t bpos;
111 
112 	if (size > MLEN)
113 		panic("mb_reserve: size = %d\n", size);
114 	m = mbp->mb_cur;
115 	if (mbp->mb_mleft < size) {
116 		mn = m_get(M_TRYWAIT, MT_DATA);
117 		if (mn == NULL)
118 			return NULL;
119 		mbp->mb_cur = m->m_next = mn;
120 		m = mn;
121 		m->m_len = 0;
122 		mbp->mb_mleft = M_TRAILINGSPACE(m);
123 	}
124 	mbp->mb_mleft -= size;
125 	mbp->mb_count += size;
126 	bpos = mtod(m, caddr_t) + m->m_len;
127 	m->m_len += size;
128 	return bpos;
129 }
130 
131 int
132 mb_put_uint8(struct mbchain *mbp, u_int8_t x)
133 {
134 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
135 }
136 
137 int
138 mb_put_uint16be(struct mbchain *mbp, u_int16_t x)
139 {
140 	x = htobe16(x);
141 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
142 }
143 
144 int
145 mb_put_uint16le(struct mbchain *mbp, u_int16_t x)
146 {
147 	x = htole16(x);
148 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
149 }
150 
151 int
152 mb_put_uint32be(struct mbchain *mbp, u_int32_t x)
153 {
154 	x = htobe32(x);
155 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
156 }
157 
158 int
159 mb_put_uint32le(struct mbchain *mbp, u_int32_t x)
160 {
161 	x = htole32(x);
162 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
163 }
164 
165 int
166 mb_put_int64be(struct mbchain *mbp, int64_t x)
167 {
168 	x = htobe64(x);
169 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
170 }
171 
172 int
173 mb_put_int64le(struct mbchain *mbp, int64_t x)
174 {
175 	x = htole64(x);
176 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
177 }
178 
179 int
180 mb_put_mem(struct mbchain *mbp, c_caddr_t source, int size, int type)
181 {
182 	struct mbuf *m;
183 	caddr_t dst;
184 	c_caddr_t src;
185 	int cplen, error, mleft, count;
186 
187 	m = mbp->mb_cur;
188 	mleft = mbp->mb_mleft;
189 
190 	while (size > 0) {
191 		if (mleft == 0) {
192 			if (m->m_next == NULL) {
193 				m = m_getm(m, size, M_TRYWAIT, MT_DATA);
194 				if (m == NULL)
195 					return ENOBUFS;
196 			} else
197 				m = m->m_next;
198 			mleft = M_TRAILINGSPACE(m);
199 			continue;
200 		}
201 		cplen = mleft > size ? size : mleft;
202 		dst = mtod(m, caddr_t) + m->m_len;
203 		switch (type) {
204 		    case MB_MCUSTOM:
205 			error = mbp->mb_copy(mbp, source, dst, cplen);
206 			if (error)
207 				return error;
208 			break;
209 		    case MB_MINLINE:
210 			for (src = source, count = cplen; count; count--)
211 				*dst++ = *src++;
212 			break;
213 		    case MB_MSYSTEM:
214 			bcopy(source, dst, cplen);
215 			break;
216 		    case MB_MUSER:
217 			error = copyin(source, dst, cplen);
218 			if (error)
219 				return error;
220 			break;
221 		    case MB_MZERO:
222 			bzero(dst, cplen);
223 			break;
224 		}
225 		size -= cplen;
226 		source += cplen;
227 		m->m_len += cplen;
228 		mleft -= cplen;
229 		mbp->mb_count += cplen;
230 	}
231 	mbp->mb_cur = m;
232 	mbp->mb_mleft = mleft;
233 	return 0;
234 }
235 
236 int
237 mb_put_mbuf(struct mbchain *mbp, struct mbuf *m)
238 {
239 	mbp->mb_cur->m_next = m;
240 	while (m) {
241 		mbp->mb_count += m->m_len;
242 		if (m->m_next == NULL)
243 			break;
244 		m = m->m_next;
245 	}
246 	mbp->mb_mleft = M_TRAILINGSPACE(m);
247 	mbp->mb_cur = m;
248 	return 0;
249 }
250 
251 /*
252  * copies a uio scatter/gather list to an mbuf chain.
253  */
254 int
255 mb_put_uio(struct mbchain *mbp, struct uio *uiop, int size)
256 {
257 	long left;
258 	int mtype, error;
259 
260 	mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
261 
262 	while (size > 0 && uiop->uio_resid) {
263 		if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
264 			return EFBIG;
265 		left = uiop->uio_iov->iov_len;
266 		if (left == 0) {
267 			uiop->uio_iov++;
268 			uiop->uio_iovcnt--;
269 			continue;
270 		}
271 		if (left > size)
272 			left = size;
273 		error = mb_put_mem(mbp, uiop->uio_iov->iov_base, left, mtype);
274 		if (error)
275 			return error;
276 		uiop->uio_offset += left;
277 		uiop->uio_resid -= left;
278 		uiop->uio_iov->iov_base =
279 		    (char *)uiop->uio_iov->iov_base + left;
280 		uiop->uio_iov->iov_len -= left;
281 		size -= left;
282 	}
283 	return 0;
284 }
285 
286 /*
287  * Routines for fetching data from an mbuf chain
288  */
289 int
290 md_init(struct mdchain *mdp)
291 {
292 	struct mbuf *m;
293 
294 	m = m_gethdr(M_TRYWAIT, MT_DATA);
295 	if (m == NULL)
296 		return ENOBUFS;
297 	m->m_len = 0;
298 	md_initm(mdp, m);
299 	return 0;
300 }
301 
302 void
303 md_initm(struct mdchain *mdp, struct mbuf *m)
304 {
305 	bzero(mdp, sizeof(*mdp));
306 	mdp->md_top = mdp->md_cur = m;
307 	mdp->md_pos = mtod(m, u_char*);
308 }
309 
310 void
311 md_done(struct mdchain *mdp)
312 {
313 	if (mdp->md_top) {
314 		m_freem(mdp->md_top);
315 		mdp->md_top = NULL;
316 	}
317 }
318 
319 /*
320  * Append a separate mbuf chain. It is caller responsibility to prevent
321  * multiple calls to fetch/record routines.
322  */
323 void
324 md_append_record(struct mdchain *mdp, struct mbuf *top)
325 {
326 	struct mbuf *m;
327 
328 	if (mdp->md_top == NULL) {
329 		md_initm(mdp, top);
330 		return;
331 	}
332 	m = mdp->md_top;
333 	while (m->m_nextpkt)
334 		m = m->m_nextpkt;
335 	m->m_nextpkt = top;
336 	top->m_nextpkt = NULL;
337 	return;
338 }
339 
340 /*
341  * Put next record in place of existing
342  */
343 int
344 md_next_record(struct mdchain *mdp)
345 {
346 	struct mbuf *m;
347 
348 	if (mdp->md_top == NULL)
349 		return ENOENT;
350 	m = mdp->md_top->m_nextpkt;
351 	md_done(mdp);
352 	if (m == NULL)
353 		return ENOENT;
354 	md_initm(mdp, m);
355 	return 0;
356 }
357 
358 int
359 md_get_uint8(struct mdchain *mdp, u_int8_t *x)
360 {
361 	return md_get_mem(mdp, x, 1, MB_MINLINE);
362 }
363 
364 int
365 md_get_uint16(struct mdchain *mdp, u_int16_t *x)
366 {
367 	return md_get_mem(mdp, (caddr_t)x, 2, MB_MINLINE);
368 }
369 
370 int
371 md_get_uint16le(struct mdchain *mdp, u_int16_t *x)
372 {
373 	u_int16_t v;
374 	int error = md_get_uint16(mdp, &v);
375 
376 	if (x != NULL)
377 		*x = le16toh(v);
378 	return error;
379 }
380 
381 int
382 md_get_uint16be(struct mdchain *mdp, u_int16_t *x) {
383 	u_int16_t v;
384 	int error = md_get_uint16(mdp, &v);
385 
386 	if (x != NULL)
387 		*x = be16toh(v);
388 	return error;
389 }
390 
391 int
392 md_get_uint32(struct mdchain *mdp, u_int32_t *x)
393 {
394 	return md_get_mem(mdp, (caddr_t)x, 4, MB_MINLINE);
395 }
396 
397 int
398 md_get_uint32be(struct mdchain *mdp, u_int32_t *x)
399 {
400 	u_int32_t v;
401 	int error;
402 
403 	error = md_get_uint32(mdp, &v);
404 	if (x != NULL)
405 		*x = be32toh(v);
406 	return error;
407 }
408 
409 int
410 md_get_uint32le(struct mdchain *mdp, u_int32_t *x)
411 {
412 	u_int32_t v;
413 	int error;
414 
415 	error = md_get_uint32(mdp, &v);
416 	if (x != NULL)
417 		*x = le32toh(v);
418 	return error;
419 }
420 
421 int
422 md_get_int64(struct mdchain *mdp, int64_t *x)
423 {
424 	return md_get_mem(mdp, (caddr_t)x, 8, MB_MINLINE);
425 }
426 
427 int
428 md_get_int64be(struct mdchain *mdp, int64_t *x)
429 {
430 	int64_t v;
431 	int error;
432 
433 	error = md_get_int64(mdp, &v);
434 	if (x != NULL)
435 		*x = be64toh(v);
436 	return error;
437 }
438 
439 int
440 md_get_int64le(struct mdchain *mdp, int64_t *x)
441 {
442 	int64_t v;
443 	int error;
444 
445 	error = md_get_int64(mdp, &v);
446 	if (x != NULL)
447 		*x = le64toh(v);
448 	return error;
449 }
450 
451 int
452 md_get_mem(struct mdchain *mdp, caddr_t target, int size, int type)
453 {
454 	struct mbuf *m = mdp->md_cur;
455 	int error;
456 	u_int count;
457 	u_char *s;
458 
459 	while (size > 0) {
460 		if (m == NULL) {
461 			MBERROR("incomplete copy\n");
462 			return EBADRPC;
463 		}
464 		s = mdp->md_pos;
465 		count = mtod(m, u_char*) + m->m_len - s;
466 		if (count == 0) {
467 			mdp->md_cur = m = m->m_next;
468 			if (m)
469 				s = mdp->md_pos = mtod(m, caddr_t);
470 			continue;
471 		}
472 		if (count > size)
473 			count = size;
474 		size -= count;
475 		mdp->md_pos += count;
476 		if (target == NULL)
477 			continue;
478 		switch (type) {
479 		    case MB_MUSER:
480 			error = copyout(s, target, count);
481 			if (error)
482 				return error;
483 			break;
484 		    case MB_MSYSTEM:
485 			bcopy(s, target, count);
486 			break;
487 		    case MB_MINLINE:
488 			while (count--)
489 				*target++ = *s++;
490 			continue;
491 		}
492 		target += count;
493 	}
494 	return 0;
495 }
496 
497 int
498 md_get_mbuf(struct mdchain *mdp, int size, struct mbuf **ret)
499 {
500 	struct mbuf *m = mdp->md_cur, *rm;
501 
502 	rm = m_copym(m, mdp->md_pos - mtod(m, u_char*), size, M_TRYWAIT);
503 	if (rm == NULL)
504 		return EBADRPC;
505 	md_get_mem(mdp, NULL, size, MB_MZERO);
506 	*ret = rm;
507 	return 0;
508 }
509 
510 int
511 md_get_uio(struct mdchain *mdp, struct uio *uiop, int size)
512 {
513 	char *uiocp;
514 	long left;
515 	int mtype, error;
516 
517 	mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
518 	while (size > 0 && uiop->uio_resid) {
519 		if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
520 			return EFBIG;
521 		left = uiop->uio_iov->iov_len;
522 		if (left == 0) {
523 			uiop->uio_iov++;
524 			uiop->uio_iovcnt--;
525 			continue;
526 		}
527 		uiocp = uiop->uio_iov->iov_base;
528 		if (left > size)
529 			left = size;
530 		error = md_get_mem(mdp, uiocp, left, mtype);
531 		if (error)
532 			return error;
533 		uiop->uio_offset += left;
534 		uiop->uio_resid -= left;
535 		uiop->uio_iov->iov_base =
536 		    (char *)uiop->uio_iov->iov_base + left;
537 		uiop->uio_iov->iov_len -= left;
538 		size -= left;
539 	}
540 	return 0;
541 }
542