nfs_boot.c revision 1.62.4.1 1 /* $NetBSD: nfs_boot.c,v 1.62.4.1 2006/09/09 02:59:24 rpaulo Exp $ */
2
3 /*-
4 * Copyright (c) 1995, 1997 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Adam Glass and Gordon W. Ross.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the NetBSD
21 * Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 /*
40 * Support for NFS diskless booting, specifically getting information
41 * about where to mount root from, what pathnames, etc.
42 */
43
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: nfs_boot.c,v 1.62.4.1 2006/09/09 02:59:24 rpaulo Exp $");
46
47 #include "opt_nfs.h"
48 #include "opt_nfs_boot.h"
49
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/kernel.h>
53 #include <sys/device.h>
54 #include <sys/ioctl.h>
55 #include <sys/proc.h>
56 #include <sys/mount.h>
57 #include <sys/mbuf.h>
58 #include <sys/reboot.h>
59 #include <sys/socket.h>
60 #include <sys/socketvar.h>
61
62 #include <net/if.h>
63 #include <net/route.h>
64 #include <net/if_ether.h>
65 #include <net/if_types.h>
66
67 #include <netinet/in.h>
68 #include <netinet/if_inarp.h>
69
70 #include <nfs/rpcv2.h>
71 #include <nfs/krpc.h>
72 #include <nfs/xdr_subs.h>
73
74 #include <nfs/nfsproto.h>
75 #include <nfs/nfs.h>
76 #include <nfs/nfsmount.h>
77 #include <nfs/nfsdiskless.h>
78
79 /*
80 * There are two implementations of NFS diskless boot.
81 * One implementation uses BOOTP (RFC951, RFC1048),
82 * the other uses Sun RPC/bootparams. See the files:
83 * nfs_bootp.c: BOOTP (RFC951, RFC1048)
84 * nfs_bootsun.c: Sun RPC/bootparams
85 */
86 #if defined(NFS_BOOT_BOOTP) || defined(NFS_BOOT_DHCP)
87 int nfs_boot_rfc951 = 1; /* BOOTP enabled (default) */
88 #endif
89 #ifdef NFS_BOOT_BOOTPARAM
90 int nfs_boot_bootparam = 1; /* BOOTPARAM enabled (default) */
91 #endif
92 #ifdef NFS_BOOT_BOOTSTATIC
93 int nfs_boot_bootstatic = 1; /* BOOTSTATIC enabled (default) */
94 #endif
95
96 /* mountd RPC */
97 static int md_mount __P((struct sockaddr_in *mdsin, char *path,
98 struct nfs_args *argp, struct lwp *l));
99
100 static void nfs_boot_defrt __P((struct in_addr *));
101 static int nfs_boot_getfh __P((struct nfs_dlmount *ndm, struct lwp *));
102
103
104 /*
105 * Called with an empty nfs_diskless struct to be filled in.
106 * Find an interface, determine its ip address (etc.) and
107 * save all the boot parameters in the nfs_diskless struct.
108 */
109 int
110 nfs_boot_init(nd, lwp)
111 struct nfs_diskless *nd;
112 struct lwp *lwp;
113 {
114 struct ifnet *ifp;
115 int error;
116
117 /*
118 * Find the network interface.
119 */
120 ifp = ifunit(root_device->dv_xname);
121 if (ifp == NULL) {
122 printf("nfs_boot: '%s' not found\n",
123 root_device->dv_xname);
124 return (ENXIO);
125 }
126 nd->nd_ifp = ifp;
127
128 error = EADDRNOTAVAIL; /* ??? */
129 #if defined(NFS_BOOT_BOOTSTATIC)
130 if (error && nfs_boot_bootstatic) {
131 printf("nfs_boot: trying static\n");
132 error = nfs_bootstatic(nd, lwp);
133 }
134 #endif
135 #if defined(NFS_BOOT_BOOTP) || defined(NFS_BOOT_DHCP)
136 if (error && nfs_boot_rfc951) {
137 #if defined(NFS_BOOT_DHCP)
138 printf("nfs_boot: trying DHCP/BOOTP\n");
139 #else
140 printf("nfs_boot: trying BOOTP\n");
141 #endif
142 error = nfs_bootdhcp(nd, lwp);
143 }
144 #endif
145 #ifdef NFS_BOOT_BOOTPARAM
146 if (error && nfs_boot_bootparam) {
147 printf("nfs_boot: trying RARP (and RPC/bootparam)\n");
148 error = nfs_bootparam(nd, lwp);
149 }
150 #endif
151 if (error)
152 return (error);
153
154 /*
155 * If the gateway address is set, add a default route.
156 * (The mountd RPCs may go across a gateway.)
157 */
158 if (nd->nd_gwip.s_addr)
159 nfs_boot_defrt(&nd->nd_gwip);
160
161 /*
162 * Now fetch the NFS file handles as appropriate.
163 */
164 error = nfs_boot_getfh(&nd->nd_root, lwp);
165
166 if (error)
167 nfs_boot_cleanup(nd, lwp);
168
169 return (error);
170 }
171
172 void
173 nfs_boot_cleanup(nd, lwp)
174 struct nfs_diskless *nd;
175 struct lwp *lwp;
176 {
177
178 nfs_boot_deladdress(nd->nd_ifp, lwp, nd->nd_myip.s_addr);
179 nfs_boot_ifupdown(nd->nd_ifp, lwp, 0);
180 nfs_boot_flushrt(nd->nd_ifp);
181 }
182
183 int
184 nfs_boot_ifupdown(ifp, lwp, up)
185 struct ifnet *ifp;
186 struct lwp *lwp;
187 int up;
188 {
189 struct socket *so;
190 struct ifreq ireq;
191 int error;
192
193 memset(&ireq, 0, sizeof(ireq));
194 memcpy(ireq.ifr_name, ifp->if_xname, IFNAMSIZ);
195
196 /*
197 * Get a socket to use for various things in here.
198 * After this, use "goto out" to cleanup and return.
199 */
200 error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp);
201 if (error) {
202 printf("ifupdown: socreate, error=%d\n", error);
203 return (error);
204 }
205
206 /*
207 * Bring up the interface. (just set the "up" flag)
208 * Get the old interface flags and or IFF_UP into them so
209 * things like media selection flags are not clobbered.
210 */
211 error = ifioctl(so, SIOCGIFFLAGS, (caddr_t)&ireq, lwp);
212 if (error) {
213 printf("ifupdown: GIFFLAGS, error=%d\n", error);
214 goto out;
215 }
216 if (up)
217 ireq.ifr_flags |= IFF_UP;
218 else
219 ireq.ifr_flags &= ~IFF_UP;
220 error = ifioctl(so, SIOCSIFFLAGS, (caddr_t)&ireq, lwp);
221 if (error) {
222 printf("ifupdown: SIFFLAGS, error=%d\n", error);
223 goto out;
224 }
225
226 if (up)
227 /* give the link some time to get up */
228 tsleep(nfs_boot_ifupdown, PZERO, "nfsbif", 3 * hz);
229 out:
230 soclose(so);
231 return (error);
232 }
233
234 int
235 nfs_boot_setaddress(ifp, lwp, addr, netmask, braddr)
236 struct ifnet *ifp;
237 struct lwp *lwp;
238 u_int32_t addr, netmask, braddr;
239 {
240 struct socket *so;
241 struct ifaliasreq iareq;
242 struct sockaddr_in *sin;
243 int error;
244
245 /*
246 * Get a socket to use for various things in here.
247 * After this, use "goto out" to cleanup and return.
248 */
249 error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp);
250 if (error) {
251 printf("setaddress: socreate, error=%d\n", error);
252 return (error);
253 }
254
255 memset(&iareq, 0, sizeof(iareq));
256 memcpy(iareq.ifra_name, ifp->if_xname, IFNAMSIZ);
257
258 /* Set the I/F address */
259 sin = (struct sockaddr_in *)&iareq.ifra_addr;
260 sin->sin_len = sizeof(*sin);
261 sin->sin_family = AF_INET;
262 sin->sin_addr.s_addr = addr;
263
264 /* Set the netmask */
265 if (netmask != INADDR_ANY) {
266 sin = (struct sockaddr_in *)&iareq.ifra_mask;
267 sin->sin_len = sizeof(*sin);
268 sin->sin_family = AF_INET;
269 sin->sin_addr.s_addr = netmask;
270 } /* else leave subnetmask unspecified (len=0) */
271
272 /* Set the broadcast addr. */
273 if (braddr != INADDR_ANY) {
274 sin = (struct sockaddr_in *)&iareq.ifra_broadaddr;
275 sin->sin_len = sizeof(*sin);
276 sin->sin_family = AF_INET;
277 sin->sin_addr.s_addr = braddr;
278 } /* else leave broadcast addr unspecified (len=0) */
279
280 error = ifioctl(so, SIOCAIFADDR, (caddr_t)&iareq, lwp);
281 if (error) {
282 printf("setaddress, error=%d\n", error);
283 goto out;
284 }
285
286 /* give the link some time to get up */
287 tsleep(nfs_boot_setaddress, PZERO, "nfsbtd", 3 * hz);
288 out:
289 soclose(so);
290 return (error);
291 }
292
293 int
294 nfs_boot_deladdress(ifp, lwp, addr)
295 struct ifnet *ifp;
296 struct lwp *lwp;
297 u_int32_t addr;
298 {
299 struct socket *so;
300 struct ifreq ireq;
301 struct sockaddr_in *sin;
302 int error;
303
304 /*
305 * Get a socket to use for various things in here.
306 * After this, use "goto out" to cleanup and return.
307 */
308 error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp);
309 if (error) {
310 printf("deladdress: socreate, error=%d\n", error);
311 return (error);
312 }
313
314 memset(&ireq, 0, sizeof(ireq));
315 memcpy(ireq.ifr_name, ifp->if_xname, IFNAMSIZ);
316
317 sin = (struct sockaddr_in *)&ireq.ifr_addr;
318 sin->sin_len = sizeof(*sin);
319 sin->sin_family = AF_INET;
320 sin->sin_addr.s_addr = addr;
321
322 error = ifioctl(so, SIOCDIFADDR, (caddr_t)&ireq, lwp);
323 if (error) {
324 printf("deladdress, error=%d\n", error);
325 goto out;
326 }
327
328 out:
329 soclose(so);
330 return (error);
331 }
332
333 int
334 nfs_boot_setrecvtimo(so)
335 struct socket *so;
336 {
337 struct mbuf *m;
338 struct timeval *tv;
339
340 m = m_get(M_WAIT, MT_SOOPTS);
341 tv = mtod(m, struct timeval *);
342 m->m_len = sizeof(*tv);
343 tv->tv_sec = 1;
344 tv->tv_usec = 0;
345 return (sosetopt(so, SOL_SOCKET, SO_RCVTIMEO, m));
346 }
347
348 int
349 nfs_boot_enbroadcast(so)
350 struct socket *so;
351 {
352 struct mbuf *m;
353 int32_t *on;
354
355 m = m_get(M_WAIT, MT_SOOPTS);
356 on = mtod(m, int32_t *);
357 m->m_len = sizeof(*on);
358 *on = 1;
359 return (sosetopt(so, SOL_SOCKET, SO_BROADCAST, m));
360 }
361
362 int
363 nfs_boot_sobind_ipport(so, port, l)
364 struct socket *so;
365 u_int16_t port;
366 struct lwp *l;
367 {
368 struct mbuf *m;
369 struct sockaddr_in *sin;
370 int error;
371
372 m = m_getclr(M_WAIT, MT_SONAME);
373 sin = mtod(m, struct sockaddr_in *);
374 sin->sin_len = m->m_len = sizeof(*sin);
375 sin->sin_family = AF_INET;
376 sin->sin_addr.s_addr = INADDR_ANY;
377 sin->sin_port = htons(port);
378 error = sobind(so, m, l);
379 m_freem(m);
380 return (error);
381 }
382
383 /*
384 * What is the longest we will wait before re-sending a request?
385 * Note this is also the frequency of "timeout" messages.
386 * The re-send loop counts up linearly to this maximum, so the
387 * first complaint will happen after (1+2+3+4+5)=15 seconds.
388 */
389 #define MAX_RESEND_DELAY 5 /* seconds */
390 #define TOTAL_TIMEOUT 30 /* seconds */
391
392 int
393 nfs_boot_sendrecv(so, nam, sndproc, snd, rcvproc, rcv, from_p, context, lwp)
394 struct socket *so;
395 struct mbuf *nam;
396 int (*sndproc) __P((struct mbuf*, void*, int));
397 struct mbuf *snd;
398 int (*rcvproc) __P((struct mbuf*, void*));
399 struct mbuf **rcv, **from_p;
400 void *context;
401 struct lwp *lwp;
402 {
403 int error, rcvflg, timo, secs, waited;
404 struct mbuf *m, *from;
405 struct uio uio;
406
407 /* Free at end if not null. */
408 from = NULL;
409
410 /*
411 * Send it, repeatedly, until a reply is received,
412 * but delay each re-send by an increasing amount.
413 * If the delay hits the maximum, start complaining.
414 */
415 waited = timo = 0;
416 send_again:
417 waited += timo;
418 if (waited >= TOTAL_TIMEOUT)
419 return (ETIMEDOUT);
420
421 /* Determine new timeout. */
422 if (timo < MAX_RESEND_DELAY)
423 timo++;
424 else
425 printf("nfs_boot: timeout...\n");
426
427 if (sndproc) {
428 error = (*sndproc)(snd, context, waited);
429 if (error)
430 goto out;
431 }
432
433 /* Send request (or re-send). */
434 m = m_copypacket(snd, M_WAIT);
435 if (m == NULL) {
436 error = ENOBUFS;
437 goto out;
438 }
439 error = (*so->so_send)(so, nam, NULL, m, NULL, 0, lwp);
440 if (error) {
441 printf("nfs_boot: sosend: %d\n", error);
442 goto out;
443 }
444 m = NULL;
445
446 /*
447 * Wait for up to timo seconds for a reply.
448 * The socket receive timeout was set to 1 second.
449 */
450
451 secs = timo;
452 for (;;) {
453 if (from) {
454 m_freem(from);
455 from = NULL;
456 }
457 if (m) {
458 m_freem(m);
459 m = NULL;
460 }
461 uio.uio_resid = 1 << 16; /* ??? */
462 rcvflg = 0;
463 error = (*so->so_receive)(so, &from, &uio, &m, NULL, &rcvflg);
464 if (error == EWOULDBLOCK) {
465 if (--secs <= 0)
466 goto send_again;
467 continue;
468 }
469 if (error)
470 goto out;
471 #ifdef DIAGNOSTIC
472 if (!m || !(m->m_flags & M_PKTHDR)
473 || (1 << 16) - uio.uio_resid != m->m_pkthdr.len)
474 panic("nfs_boot_sendrecv: return size");
475 #endif
476
477 if ((*rcvproc)(m, context))
478 continue;
479
480 if (rcv)
481 *rcv = m;
482 else
483 m_freem(m);
484 if (from_p) {
485 *from_p = from;
486 from = NULL;
487 }
488 break;
489 }
490 out:
491 if (from) m_freem(from);
492 return (error);
493 }
494
495 /*
496 * Install a default route to the passed IP address.
497 */
498 static void
499 nfs_boot_defrt(gw_ip)
500 struct in_addr *gw_ip;
501 {
502 struct sockaddr dst, gw, mask;
503 struct sockaddr_in *sin;
504 int error;
505
506 /* Destination: (default) */
507 memset((caddr_t)&dst, 0, sizeof(dst));
508 dst.sa_len = sizeof(dst);
509 dst.sa_family = AF_INET;
510 /* Gateway: */
511 memset((caddr_t)&gw, 0, sizeof(gw));
512 sin = (struct sockaddr_in *)&gw;
513 sin->sin_len = sizeof(*sin);
514 sin->sin_family = AF_INET;
515 sin->sin_addr.s_addr = gw_ip->s_addr;
516 /* Mask: (zero length) */
517 /* XXX - Just pass a null pointer? */
518 memset(&mask, 0, sizeof(mask));
519
520 /* add, dest, gw, mask, flags, 0 */
521 error = rtrequest(RTM_ADD, &dst, &gw, &mask,
522 (RTF_UP | RTF_GATEWAY | RTF_STATIC), NULL);
523 if (error) {
524 printf("nfs_boot: add route, error=%d\n", error);
525 error = 0;
526 }
527 }
528
529 static int nfs_boot_delroute __P((struct radix_node *, void *));
530 static int
531 nfs_boot_delroute(rn, w)
532 struct radix_node *rn;
533 void *w;
534 {
535 struct rtentry *rt = (struct rtentry *)rn;
536 int error;
537
538 if (rt->rt_ifp != (struct ifnet *)w)
539 return (0);
540
541 error = rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL);
542 if (error)
543 printf("nfs_boot: del route, error=%d\n", error);
544
545 return (0);
546 }
547
548 void
549 nfs_boot_flushrt(ifp)
550 struct ifnet *ifp;
551 {
552
553 rn_walktree(rt_tables[AF_INET], nfs_boot_delroute, ifp);
554 }
555
556 /*
557 * Get an initial NFS file handle using Sun RPC/mountd.
558 * Separate function because we used to call it twice.
559 * (once for root and once for swap)
560 */
561 static int
562 nfs_boot_getfh(ndm, l)
563 struct nfs_dlmount *ndm; /* output */
564 struct lwp *l;
565 {
566 struct nfs_args *args;
567 struct sockaddr_in *sin;
568 char *pathname;
569 int error;
570 u_int16_t port;
571
572 args = &ndm->ndm_args;
573
574 /* Initialize mount args. */
575 memset((caddr_t) args, 0, sizeof(*args));
576 args->addr = &ndm->ndm_saddr;
577 args->addrlen = args->addr->sa_len;
578 #ifdef NFS_BOOT_TCP
579 args->sotype = SOCK_STREAM;
580 #else
581 args->sotype = SOCK_DGRAM;
582 #endif
583 args->fh = ndm->ndm_fh;
584 args->hostname = ndm->ndm_host;
585 args->flags = NFSMNT_NOCONN | NFSMNT_RESVPORT;
586
587 #ifndef NFS_V2_ONLY
588 args->flags |= NFSMNT_NFSV3;
589 #endif
590 #ifdef NFS_BOOT_OPTIONS
591 args->flags |= NFS_BOOT_OPTIONS;
592 #endif
593 #ifdef NFS_BOOT_RWSIZE
594 /*
595 * Reduce rsize,wsize for interfaces that consistently
596 * drop fragments of long UDP messages. (i.e. wd8003).
597 * You can always change these later via remount.
598 */
599 args->flags |= NFSMNT_WSIZE | NFSMNT_RSIZE;
600 args->wsize = NFS_BOOT_RWSIZE;
601 args->rsize = NFS_BOOT_RWSIZE;
602 #endif
603
604 /*
605 * Find the pathname part of the "server:pathname"
606 * string left in ndm->ndm_host by nfs_boot_init.
607 */
608 pathname = strchr(ndm->ndm_host, ':');
609 if (pathname == 0) {
610 printf("nfs_boot: getfh - no pathname\n");
611 return (EIO);
612 }
613 pathname++;
614
615 /*
616 * Get file handle using RPC to mountd/mount
617 */
618 sin = (struct sockaddr_in *)&ndm->ndm_saddr;
619 error = md_mount(sin, pathname, args, l);
620 if (error) {
621 printf("nfs_boot: mountd `%s', error=%d\n",
622 ndm->ndm_host, error);
623 return (error);
624 }
625
626 /* Set port number for NFS use. */
627 /* XXX: NFS port is always 2049, right? */
628 #ifdef NFS_BOOT_TCP
629 retry:
630 #endif
631 error = krpc_portmap(sin, NFS_PROG,
632 (args->flags & NFSMNT_NFSV3) ? NFS_VER3 : NFS_VER2,
633 (args->sotype == SOCK_STREAM) ? IPPROTO_TCP : IPPROTO_UDP,
634 &port, l);
635 if (port == htons(0))
636 error = EIO;
637 if (error) {
638 #ifdef NFS_BOOT_TCP
639 if (args->sotype == SOCK_STREAM) {
640 args->sotype = SOCK_DGRAM;
641 goto retry;
642 }
643 #endif
644 printf("nfs_boot: portmap NFS, error=%d\n", error);
645 return (error);
646 }
647 sin->sin_port = port;
648 return (0);
649 }
650
651
652 /*
653 * RPC: mountd/mount
654 * Given a server pathname, get an NFS file handle.
655 * Also, sets sin->sin_port to the NFS service port.
656 */
657 static int
658 md_mount(mdsin, path, argp, lwp)
659 struct sockaddr_in *mdsin; /* mountd server address */
660 char *path;
661 struct nfs_args *argp;
662 struct lwp *lwp;
663 {
664 /* The RPC structures */
665 struct rdata {
666 u_int32_t errno;
667 union {
668 u_int8_t v2fh[NFSX_V2FH];
669 struct {
670 u_int32_t fhlen;
671 u_int8_t fh[1];
672 } v3fh;
673 } fh;
674 } *rdata;
675 struct mbuf *m;
676 u_int8_t *fh;
677 int minlen, error;
678 int mntver;
679
680 mntver = (argp->flags & NFSMNT_NFSV3) ? 3 : 2;
681 do {
682 /*
683 * Get port number for MOUNTD.
684 */
685 error = krpc_portmap(mdsin, RPCPROG_MNT, mntver,
686 IPPROTO_UDP, &mdsin->sin_port, lwp);
687 if (error)
688 continue;
689
690 /* This mbuf is consumed by krpc_call. */
691 m = xdr_string_encode(path, strlen(path));
692 if (m == NULL)
693 return ENOMEM;
694
695 /* Do RPC to mountd. */
696 error = krpc_call(mdsin, RPCPROG_MNT, mntver,
697 RPCMNT_MOUNT, &m, NULL, lwp);
698 if (error != EPROGMISMATCH)
699 break;
700 /* Try lower version of mountd. */
701 } while (--mntver >= 1);
702 if (error) {
703 printf("nfs_boot: mountd error=%d\n", error);
704 return error;
705 }
706 if (mntver != 3)
707 argp->flags &= ~NFSMNT_NFSV3;
708
709 /* The reply might have only the errno. */
710 if (m->m_len < 4)
711 goto bad;
712 /* Have at least errno, so check that. */
713 rdata = mtod(m, struct rdata *);
714 error = fxdr_unsigned(u_int32_t, rdata->errno);
715 if (error)
716 goto out;
717
718 /* Have errno==0, so the fh must be there. */
719 if (mntver == 3) {
720 argp->fhsize = fxdr_unsigned(u_int32_t, rdata->fh.v3fh.fhlen);
721 if (argp->fhsize > NFSX_V3FHMAX)
722 goto bad;
723 minlen = 2 * sizeof(u_int32_t) + argp->fhsize;
724 } else {
725 argp->fhsize = NFSX_V2FH;
726 minlen = sizeof(u_int32_t) + argp->fhsize;
727 }
728
729 if (m->m_len < minlen) {
730 m = m_pullup(m, minlen);
731 if (m == NULL)
732 return(EBADRPC);
733 rdata = mtod(m, struct rdata *);
734 }
735
736 fh = (mntver == 3) ?
737 rdata->fh.v3fh.fh : rdata->fh.v2fh;
738 memcpy(argp->fh, fh, argp->fhsize);
739
740 goto out;
741
742 bad:
743 error = EBADRPC;
744
745 out:
746 m_freem(m);
747 return error;
748 }
749