xref: /freebsd/sys/kern/subr_mchain.c (revision 39beb93c)
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_WAIT, MT_DATA);
60 	m->m_len = 0;
61 	mb_initm(mbp, m);
62 	return 0;
63 }
64 
65 void
66 mb_initm(struct mbchain *mbp, struct mbuf *m)
67 {
68 	bzero(mbp, sizeof(*mbp));
69 	mbp->mb_top = mbp->mb_cur = m;
70 	mbp->mb_mleft = M_TRAILINGSPACE(m);
71 }
72 
73 void
74 mb_done(struct mbchain *mbp)
75 {
76 	if (mbp->mb_top) {
77 		m_freem(mbp->mb_top);
78 		mbp->mb_top = NULL;
79 	}
80 }
81 
82 struct mbuf *
83 mb_detach(struct mbchain *mbp)
84 {
85 	struct mbuf *m;
86 
87 	m = mbp->mb_top;
88 	mbp->mb_top = NULL;
89 	return m;
90 }
91 
92 int
93 mb_fixhdr(struct mbchain *mbp)
94 {
95 	return mbp->mb_top->m_pkthdr.len = m_fixhdr(mbp->mb_top);
96 }
97 
98 /*
99  * Check if object of size 'size' fit to the current position and
100  * allocate new mbuf if not. Advance pointers and increase length of mbuf(s).
101  * Return pointer to the object placeholder or NULL if any error occured.
102  * Note: size should be <= MLEN
103  */
104 caddr_t
105 mb_reserve(struct mbchain *mbp, int size)
106 {
107 	struct mbuf *m, *mn;
108 	caddr_t bpos;
109 
110 	if (size > MLEN)
111 		panic("mb_reserve: size = %d\n", size);
112 	m = mbp->mb_cur;
113 	if (mbp->mb_mleft < size) {
114 		mn = m_get(M_WAIT, MT_DATA);
115 		mbp->mb_cur = m->m_next = mn;
116 		m = mn;
117 		m->m_len = 0;
118 		mbp->mb_mleft = M_TRAILINGSPACE(m);
119 	}
120 	mbp->mb_mleft -= size;
121 	mbp->mb_count += size;
122 	bpos = mtod(m, caddr_t) + m->m_len;
123 	m->m_len += size;
124 	return bpos;
125 }
126 
127 int
128 mb_put_uint8(struct mbchain *mbp, u_int8_t x)
129 {
130 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
131 }
132 
133 int
134 mb_put_uint16be(struct mbchain *mbp, u_int16_t x)
135 {
136 	x = htobe16(x);
137 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
138 }
139 
140 int
141 mb_put_uint16le(struct mbchain *mbp, u_int16_t x)
142 {
143 	x = htole16(x);
144 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
145 }
146 
147 int
148 mb_put_uint32be(struct mbchain *mbp, u_int32_t x)
149 {
150 	x = htobe32(x);
151 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
152 }
153 
154 int
155 mb_put_uint32le(struct mbchain *mbp, u_int32_t x)
156 {
157 	x = htole32(x);
158 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
159 }
160 
161 int
162 mb_put_int64be(struct mbchain *mbp, int64_t x)
163 {
164 	x = htobe64(x);
165 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
166 }
167 
168 int
169 mb_put_int64le(struct mbchain *mbp, int64_t x)
170 {
171 	x = htole64(x);
172 	return mb_put_mem(mbp, (caddr_t)&x, sizeof(x), MB_MSYSTEM);
173 }
174 
175 int
176 mb_put_mem(struct mbchain *mbp, c_caddr_t source, int size, int type)
177 {
178 	struct mbuf *m;
179 	caddr_t dst;
180 	c_caddr_t src;
181 	int cplen, error, mleft, count;
182 	size_t srclen, dstlen;
183 
184 	m = mbp->mb_cur;
185 	mleft = mbp->mb_mleft;
186 
187 	while (size > 0) {
188 		if (mleft == 0) {
189 			if (m->m_next == NULL)
190 				m = m_getm(m, size, M_WAIT, MT_DATA);
191 			else
192 				m = m->m_next;
193 			mleft = M_TRAILINGSPACE(m);
194 			continue;
195 		}
196 		cplen = mleft > size ? size : mleft;
197 		srclen = dstlen = cplen;
198 		dst = mtod(m, caddr_t) + m->m_len;
199 		switch (type) {
200 		    case MB_MCUSTOM:
201 			srclen = size;
202 			dstlen = mleft;
203 			error = mbp->mb_copy(mbp, source, dst, &srclen, &dstlen);
204 			if (error)
205 				return error;
206 			break;
207 		    case MB_MINLINE:
208 			for (src = source, count = cplen; count; count--)
209 				*dst++ = *src++;
210 			break;
211 		    case MB_MSYSTEM:
212 			bcopy(source, dst, cplen);
213 			break;
214 		    case MB_MUSER:
215 			error = copyin(source, dst, cplen);
216 			if (error)
217 				return error;
218 			break;
219 		    case MB_MZERO:
220 			bzero(dst, cplen);
221 			break;
222 		}
223 		size -= srclen;
224 		source += srclen;
225 		m->m_len += dstlen;
226 		mleft -= dstlen;
227 		mbp->mb_count += dstlen;
228 	}
229 	mbp->mb_cur = m;
230 	mbp->mb_mleft = mleft;
231 	return 0;
232 }
233 
234 int
235 mb_put_mbuf(struct mbchain *mbp, struct mbuf *m)
236 {
237 	mbp->mb_cur->m_next = m;
238 	while (m) {
239 		mbp->mb_count += m->m_len;
240 		if (m->m_next == NULL)
241 			break;
242 		m = m->m_next;
243 	}
244 	mbp->mb_mleft = M_TRAILINGSPACE(m);
245 	mbp->mb_cur = m;
246 	return 0;
247 }
248 
249 /*
250  * copies a uio scatter/gather list to an mbuf chain.
251  */
252 int
253 mb_put_uio(struct mbchain *mbp, struct uio *uiop, int size)
254 {
255 	long left;
256 	int mtype, error;
257 
258 	mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
259 
260 	while (size > 0 && uiop->uio_resid) {
261 		if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
262 			return EFBIG;
263 		left = uiop->uio_iov->iov_len;
264 		if (left == 0) {
265 			uiop->uio_iov++;
266 			uiop->uio_iovcnt--;
267 			continue;
268 		}
269 		if (left > size)
270 			left = size;
271 		error = mb_put_mem(mbp, uiop->uio_iov->iov_base, left, mtype);
272 		if (error)
273 			return error;
274 		uiop->uio_offset += left;
275 		uiop->uio_resid -= left;
276 		uiop->uio_iov->iov_base =
277 		    (char *)uiop->uio_iov->iov_base + left;
278 		uiop->uio_iov->iov_len -= left;
279 		size -= left;
280 	}
281 	return 0;
282 }
283 
284 /*
285  * Routines for fetching data from an mbuf chain
286  */
287 int
288 md_init(struct mdchain *mdp)
289 {
290 	struct mbuf *m;
291 
292 	m = m_gethdr(M_WAIT, MT_DATA);
293 	m->m_len = 0;
294 	md_initm(mdp, m);
295 	return 0;
296 }
297 
298 void
299 md_initm(struct mdchain *mdp, struct mbuf *m)
300 {
301 	bzero(mdp, sizeof(*mdp));
302 	mdp->md_top = mdp->md_cur = m;
303 	mdp->md_pos = mtod(m, u_char*);
304 }
305 
306 void
307 md_done(struct mdchain *mdp)
308 {
309 	if (mdp->md_top) {
310 		m_freem(mdp->md_top);
311 		mdp->md_top = NULL;
312 	}
313 }
314 
315 /*
316  * Append a separate mbuf chain. It is caller responsibility to prevent
317  * multiple calls to fetch/record routines.
318  */
319 void
320 md_append_record(struct mdchain *mdp, struct mbuf *top)
321 {
322 	struct mbuf *m;
323 
324 	if (mdp->md_top == NULL) {
325 		md_initm(mdp, top);
326 		return;
327 	}
328 	m = mdp->md_top;
329 	while (m->m_nextpkt)
330 		m = m->m_nextpkt;
331 	m->m_nextpkt = top;
332 	top->m_nextpkt = NULL;
333 	return;
334 }
335 
336 /*
337  * Put next record in place of existing
338  */
339 int
340 md_next_record(struct mdchain *mdp)
341 {
342 	struct mbuf *m;
343 
344 	if (mdp->md_top == NULL)
345 		return ENOENT;
346 	m = mdp->md_top->m_nextpkt;
347 	md_done(mdp);
348 	if (m == NULL)
349 		return ENOENT;
350 	md_initm(mdp, m);
351 	return 0;
352 }
353 
354 int
355 md_get_uint8(struct mdchain *mdp, u_int8_t *x)
356 {
357 	return md_get_mem(mdp, x, 1, MB_MINLINE);
358 }
359 
360 int
361 md_get_uint16(struct mdchain *mdp, u_int16_t *x)
362 {
363 	return md_get_mem(mdp, (caddr_t)x, 2, MB_MINLINE);
364 }
365 
366 int
367 md_get_uint16le(struct mdchain *mdp, u_int16_t *x)
368 {
369 	u_int16_t v;
370 	int error = md_get_uint16(mdp, &v);
371 
372 	if (x != NULL)
373 		*x = le16toh(v);
374 	return error;
375 }
376 
377 int
378 md_get_uint16be(struct mdchain *mdp, u_int16_t *x) {
379 	u_int16_t v;
380 	int error = md_get_uint16(mdp, &v);
381 
382 	if (x != NULL)
383 		*x = be16toh(v);
384 	return error;
385 }
386 
387 int
388 md_get_uint32(struct mdchain *mdp, u_int32_t *x)
389 {
390 	return md_get_mem(mdp, (caddr_t)x, 4, MB_MINLINE);
391 }
392 
393 int
394 md_get_uint32be(struct mdchain *mdp, u_int32_t *x)
395 {
396 	u_int32_t v;
397 	int error;
398 
399 	error = md_get_uint32(mdp, &v);
400 	if (x != NULL)
401 		*x = be32toh(v);
402 	return error;
403 }
404 
405 int
406 md_get_uint32le(struct mdchain *mdp, u_int32_t *x)
407 {
408 	u_int32_t v;
409 	int error;
410 
411 	error = md_get_uint32(mdp, &v);
412 	if (x != NULL)
413 		*x = le32toh(v);
414 	return error;
415 }
416 
417 int
418 md_get_int64(struct mdchain *mdp, int64_t *x)
419 {
420 	return md_get_mem(mdp, (caddr_t)x, 8, MB_MINLINE);
421 }
422 
423 int
424 md_get_int64be(struct mdchain *mdp, int64_t *x)
425 {
426 	int64_t v;
427 	int error;
428 
429 	error = md_get_int64(mdp, &v);
430 	if (x != NULL)
431 		*x = be64toh(v);
432 	return error;
433 }
434 
435 int
436 md_get_int64le(struct mdchain *mdp, int64_t *x)
437 {
438 	int64_t v;
439 	int error;
440 
441 	error = md_get_int64(mdp, &v);
442 	if (x != NULL)
443 		*x = le64toh(v);
444 	return error;
445 }
446 
447 int
448 md_get_mem(struct mdchain *mdp, caddr_t target, int size, int type)
449 {
450 	struct mbuf *m = mdp->md_cur;
451 	int error;
452 	u_int count;
453 	u_char *s;
454 
455 	while (size > 0) {
456 		if (m == NULL) {
457 			MBERROR("incomplete copy\n");
458 			return EBADRPC;
459 		}
460 		s = mdp->md_pos;
461 		count = mtod(m, u_char*) + m->m_len - s;
462 		if (count == 0) {
463 			mdp->md_cur = m = m->m_next;
464 			if (m)
465 				s = mdp->md_pos = mtod(m, caddr_t);
466 			continue;
467 		}
468 		if (count > size)
469 			count = size;
470 		size -= count;
471 		mdp->md_pos += count;
472 		if (target == NULL)
473 			continue;
474 		switch (type) {
475 		    case MB_MUSER:
476 			error = copyout(s, target, count);
477 			if (error)
478 				return error;
479 			break;
480 		    case MB_MSYSTEM:
481 			bcopy(s, target, count);
482 			break;
483 		    case MB_MINLINE:
484 			while (count--)
485 				*target++ = *s++;
486 			continue;
487 		}
488 		target += count;
489 	}
490 	return 0;
491 }
492 
493 int
494 md_get_mbuf(struct mdchain *mdp, int size, struct mbuf **ret)
495 {
496 	struct mbuf *m = mdp->md_cur, *rm;
497 
498 	rm = m_copym(m, mdp->md_pos - mtod(m, u_char*), size, M_WAIT);
499 	md_get_mem(mdp, NULL, size, MB_MZERO);
500 	*ret = rm;
501 	return 0;
502 }
503 
504 int
505 md_get_uio(struct mdchain *mdp, struct uio *uiop, int size)
506 {
507 	char *uiocp;
508 	long left;
509 	int mtype, error;
510 
511 	mtype = (uiop->uio_segflg == UIO_SYSSPACE) ? MB_MSYSTEM : MB_MUSER;
512 	while (size > 0 && uiop->uio_resid) {
513 		if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
514 			return EFBIG;
515 		left = uiop->uio_iov->iov_len;
516 		if (left == 0) {
517 			uiop->uio_iov++;
518 			uiop->uio_iovcnt--;
519 			continue;
520 		}
521 		uiocp = uiop->uio_iov->iov_base;
522 		if (left > size)
523 			left = size;
524 		error = md_get_mem(mdp, uiocp, left, mtype);
525 		if (error)
526 			return error;
527 		uiop->uio_offset += left;
528 		uiop->uio_resid -= left;
529 		uiop->uio_iov->iov_base =
530 		    (char *)uiop->uio_iov->iov_base + left;
531 		uiop->uio_iov->iov_len -= left;
532 		size -= left;
533 	}
534 	return 0;
535 }
536