FreeBSD/Linux Kernel Cross Reference
sys/nfs/nfs_common.c
1 /*-
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Rick Macklem at The University of Guelph.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)nfs_subs.c 8.8 (Berkeley) 5/22/95
33 */
34
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD: releng/9.0/sys/nfs/nfs_common.c 221973 2011-05-15 20:52:43Z rmacklem $");
37
38 /*
39 * These functions support the macros and help fiddle mbuf chains for
40 * the nfs op functions. They do things like create the rpc header and
41 * copy data between mbuf chains and uio lists.
42 */
43
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/kernel.h>
47 #include <sys/bio.h>
48 #include <sys/buf.h>
49 #include <sys/proc.h>
50 #include <sys/mount.h>
51 #include <sys/vnode.h>
52 #include <sys/namei.h>
53 #include <sys/mbuf.h>
54 #include <sys/socket.h>
55 #include <sys/stat.h>
56 #include <sys/malloc.h>
57 #include <sys/module.h>
58 #include <sys/sysent.h>
59 #include <sys/syscall.h>
60 #include <sys/sysctl.h>
61
62 #include <vm/vm.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_extern.h>
65
66 #include <nfs/nfsproto.h>
67 #include <nfsserver/nfs.h>
68 #include <nfs/xdr_subs.h>
69 #include <nfs/nfs_common.h>
70
71 #include <netinet/in.h>
72
73 enum vtype nv3tov_type[8]= {
74 VNON, VREG, VDIR, VBLK, VCHR, VLNK, VSOCK, VFIFO
75 };
76 nfstype nfsv3_type[9] = {
77 NFNON, NFREG, NFDIR, NFBLK, NFCHR, NFLNK, NFSOCK, NFFIFO, NFNON
78 };
79
80 static void *nfsm_dissect_xx_sub(int s, struct mbuf **md, caddr_t *dpos,
81 int how);
82
83 SYSCTL_NODE(_vfs, OID_AUTO, nfs_common, CTLFLAG_RD, 0, "NFS common support");
84
85 static int nfs_realign_test;
86 SYSCTL_INT(_vfs_nfs_common, OID_AUTO, realign_test, CTLFLAG_RD,
87 &nfs_realign_test, 0, "Number of realign tests done");
88
89 static int nfs_realign_count;
90 SYSCTL_INT(_vfs_nfs_common, OID_AUTO, realign_count, CTLFLAG_RD,
91 &nfs_realign_count, 0, "Number of mbuf realignments done");
92
93 u_quad_t
94 nfs_curusec(void)
95 {
96 struct timeval tv;
97
98 getmicrotime(&tv);
99 return ((u_quad_t)tv.tv_sec * 1000000 + (u_quad_t)tv.tv_usec);
100 }
101
102 /*
103 * copies mbuf chain to the uio scatter/gather list
104 */
105 int
106 nfsm_mbuftouio(struct mbuf **mrep, struct uio *uiop, int siz, caddr_t *dpos)
107 {
108 char *mbufcp, *uiocp;
109 int xfer, left, len;
110 struct mbuf *mp;
111 long uiosiz, rem;
112 int error = 0;
113
114 mp = *mrep;
115 mbufcp = *dpos;
116 len = mtod(mp, caddr_t)+mp->m_len-mbufcp;
117 rem = nfsm_rndup(siz)-siz;
118 while (siz > 0) {
119 if (uiop->uio_iovcnt <= 0 || uiop->uio_iov == NULL)
120 return (EFBIG);
121 left = uiop->uio_iov->iov_len;
122 uiocp = uiop->uio_iov->iov_base;
123 if (left > siz)
124 left = siz;
125 uiosiz = left;
126 while (left > 0) {
127 while (len == 0) {
128 mp = mp->m_next;
129 if (mp == NULL)
130 return (EBADRPC);
131 mbufcp = mtod(mp, caddr_t);
132 len = mp->m_len;
133 }
134 xfer = (left > len) ? len : left;
135 #ifdef notdef
136 /* Not Yet.. */
137 if (uiop->uio_iov->iov_op != NULL)
138 (*(uiop->uio_iov->iov_op))
139 (mbufcp, uiocp, xfer);
140 else
141 #endif
142 if (uiop->uio_segflg == UIO_SYSSPACE)
143 bcopy(mbufcp, uiocp, xfer);
144 else
145 copyout(mbufcp, uiocp, xfer);
146 left -= xfer;
147 len -= xfer;
148 mbufcp += xfer;
149 uiocp += xfer;
150 uiop->uio_offset += xfer;
151 uiop->uio_resid -= xfer;
152 }
153 if (uiop->uio_iov->iov_len <= siz) {
154 uiop->uio_iovcnt--;
155 uiop->uio_iov++;
156 } else {
157 uiop->uio_iov->iov_base =
158 (char *)uiop->uio_iov->iov_base + uiosiz;
159 uiop->uio_iov->iov_len -= uiosiz;
160 }
161 siz -= uiosiz;
162 }
163 *dpos = mbufcp;
164 *mrep = mp;
165 if (rem > 0) {
166 if (len < rem)
167 error = nfs_adv(mrep, dpos, rem, len);
168 else
169 *dpos += rem;
170 }
171 return (error);
172 }
173
174 /*
175 * Help break down an mbuf chain by setting the first siz bytes contiguous
176 * pointed to by returned val.
177 * This is used by the macros nfsm_dissect for tough
178 * cases. (The macros use the vars. dpos and dpos2)
179 */
180 void *
181 nfsm_disct(struct mbuf **mdp, caddr_t *dposp, int siz, int left, int how)
182 {
183 struct mbuf *mp, *mp2;
184 int siz2, xfer;
185 caddr_t ptr, npos = NULL;
186 void *ret;
187
188 mp = *mdp;
189 while (left == 0) {
190 *mdp = mp = mp->m_next;
191 if (mp == NULL)
192 return (NULL);
193 left = mp->m_len;
194 *dposp = mtod(mp, caddr_t);
195 }
196 if (left >= siz) {
197 ret = *dposp;
198 *dposp += siz;
199 } else if (mp->m_next == NULL) {
200 return (NULL);
201 } else if (siz > MHLEN) {
202 panic("nfs S too big");
203 } else {
204 MGET(mp2, how, MT_DATA);
205 if (mp2 == NULL)
206 return (NULL);
207 mp2->m_len = siz;
208 mp2->m_next = mp->m_next;
209 mp->m_next = mp2;
210 mp->m_len -= left;
211 mp = mp2;
212 ptr = mtod(mp, caddr_t);
213 ret = ptr;
214 bcopy(*dposp, ptr, left); /* Copy what was left */
215 siz2 = siz-left;
216 ptr += left;
217 mp2 = mp->m_next;
218 npos = mtod(mp2, caddr_t);
219 /* Loop around copying up the siz2 bytes */
220 while (siz2 > 0) {
221 if (mp2 == NULL)
222 return (NULL);
223 xfer = (siz2 > mp2->m_len) ? mp2->m_len : siz2;
224 if (xfer > 0) {
225 bcopy(mtod(mp2, caddr_t), ptr, xfer);
226 mp2->m_data += xfer;
227 mp2->m_len -= xfer;
228 ptr += xfer;
229 siz2 -= xfer;
230 }
231 if (siz2 > 0) {
232 mp2 = mp2->m_next;
233 if (mp2 != NULL)
234 npos = mtod(mp2, caddr_t);
235 }
236 }
237 *mdp = mp2;
238 *dposp = mtod(mp2, caddr_t);
239 if (!nfsm_aligned(*dposp, u_int32_t)) {
240 bcopy(*dposp, npos, mp2->m_len);
241 mp2->m_data = npos;
242 *dposp = npos;
243 }
244 }
245 return (ret);
246 }
247
248 /*
249 * Advance the position in the mbuf chain.
250 */
251 int
252 nfs_adv(struct mbuf **mdp, caddr_t *dposp, int offs, int left)
253 {
254 struct mbuf *m;
255 int s;
256
257 m = *mdp;
258 s = left;
259 while (s < offs) {
260 offs -= s;
261 m = m->m_next;
262 if (m == NULL)
263 return (EBADRPC);
264 s = m->m_len;
265 }
266 *mdp = m;
267 *dposp = mtod(m, caddr_t)+offs;
268 return (0);
269 }
270
271 void *
272 nfsm_build_xx(int s, struct mbuf **mb, caddr_t *bpos)
273 {
274 struct mbuf *mb2;
275 void *ret;
276
277 if (s > M_TRAILINGSPACE(*mb)) {
278 MGET(mb2, M_WAIT, MT_DATA);
279 if (s > MLEN)
280 panic("build > MLEN");
281 (*mb)->m_next = mb2;
282 *mb = mb2;
283 (*mb)->m_len = 0;
284 *bpos = mtod(*mb, caddr_t);
285 }
286 ret = *bpos;
287 (*mb)->m_len += s;
288 *bpos += s;
289 return (ret);
290 }
291
292 void *
293 nfsm_dissect_xx(int s, struct mbuf **md, caddr_t *dpos)
294 {
295
296 return (nfsm_dissect_xx_sub(s, md, dpos, M_WAIT));
297 }
298
299 void *
300 nfsm_dissect_xx_nonblock(int s, struct mbuf **md, caddr_t *dpos)
301 {
302
303 return (nfsm_dissect_xx_sub(s, md, dpos, M_DONTWAIT));
304 }
305
306 static void *
307 nfsm_dissect_xx_sub(int s, struct mbuf **md, caddr_t *dpos, int how)
308 {
309 int t1;
310 char *cp2;
311 void *ret;
312
313 t1 = mtod(*md, caddr_t) + (*md)->m_len - *dpos;
314 if (t1 >= s) {
315 ret = *dpos;
316 *dpos += s;
317 return (ret);
318 }
319 cp2 = nfsm_disct(md, dpos, s, t1, how);
320 return (cp2);
321 }
322
323 int
324 nfsm_strsiz_xx(int *s, int m, struct mbuf **mb, caddr_t *bpos)
325 {
326 u_int32_t *tl;
327
328 tl = nfsm_dissect_xx(NFSX_UNSIGNED, mb, bpos);
329 if (tl == NULL)
330 return (EBADRPC);
331 *s = fxdr_unsigned(int32_t, *tl);
332 if (*s > m)
333 return (EBADRPC);
334 return (0);
335 }
336
337 int
338 nfsm_adv_xx(int s, struct mbuf **md, caddr_t *dpos)
339 {
340 int t1;
341
342 t1 = mtod(*md, caddr_t) + (*md)->m_len - *dpos;
343 if (t1 >= s) {
344 *dpos += s;
345 return (0);
346 }
347 t1 = nfs_adv(md, dpos, s, t1);
348 if (t1)
349 return (t1);
350 return (0);
351 }
352
353 /*
354 * Check for badly aligned mbuf data and realign by copying the unaligned
355 * portion of the data into a new mbuf chain and freeing the portions of the
356 * old chain that were replaced.
357 *
358 * We cannot simply realign the data within the existing mbuf chain because
359 * the underlying buffers may contain other rpc commands and we cannot afford
360 * to overwrite them.
361 *
362 * We would prefer to avoid this situation entirely. The situation does not
363 * occur with NFS/UDP and is supposed to only occassionally occur with TCP.
364 * Use vfs.nfs_common.realign_count and realign_test to check this.
365 */
366 int
367 nfs_realign(struct mbuf **pm, int how)
368 {
369 struct mbuf *m, *n;
370 int off;
371
372 ++nfs_realign_test;
373 while ((m = *pm) != NULL) {
374 if (!nfsm_aligned(m->m_len, u_int32_t) ||
375 !nfsm_aligned(mtod(m, intptr_t), u_int32_t)) {
376 /*
377 * NB: we can't depend on m_pkthdr.len to help us
378 * decide what to do here. May not be worth doing
379 * the m_length calculation as m_copyback will
380 * expand the mbuf chain below as needed.
381 */
382 if (m_length(m, NULL) >= MINCLSIZE) {
383 /* NB: m_copyback handles space > MCLBYTES */
384 n = m_getcl(how, MT_DATA, 0);
385 } else
386 n = m_get(how, MT_DATA);
387 if (n == NULL)
388 return (ENOMEM);
389 /*
390 * Align the remainder of the mbuf chain.
391 */
392 n->m_len = 0;
393 off = 0;
394 while (m != NULL) {
395 m_copyback(n, off, m->m_len, mtod(m, caddr_t));
396 off += m->m_len;
397 m = m->m_next;
398 }
399 m_freem(*pm);
400 *pm = n;
401 ++nfs_realign_count;
402 break;
403 }
404 pm = &m->m_next;
405 }
406 return (0);
407 }
408
409 static moduledata_t nfs_common_mod = {
410 "nfs_common",
411 NULL,
412 NULL
413 };
414
415 DECLARE_MODULE(nfs_common, nfs_common_mod, SI_SUB_VFS, SI_ORDER_ANY);
416 MODULE_VERSION(nfs_common, 1);
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