1/* $NetBSD: nfs_boot.c,v 1.87 2016/11/15 01:50:06 ozaki-r 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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * Support for NFS diskless booting, specifically getting information
34 * about where to mount root from, what pathnames, etc.
35 */
36
37#include <sys/cdefs.h>
38__KERNEL_RCSID(0, "$NetBSD: nfs_boot.c,v 1.87 2016/11/15 01:50:06 ozaki-r Exp $");
39
40#ifdef _KERNEL_OPT
41#include "opt_nfs.h"
42#include "opt_tftproot.h"
43#include "opt_nfs_boot.h"
44#endif
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/kernel.h>
49#include <sys/device.h>
50#include <sys/ioctl.h>
51#include <sys/proc.h>
52#include <sys/mount.h>
53#include <sys/mbuf.h>
54#include <sys/reboot.h>
55#include <sys/socket.h>
56#include <sys/socketvar.h>
57
58#include <net/if.h>
59#include <net/route.h>
60#include <net/if_ether.h>
61#include <net/if_types.h>
62
63#include <netinet/in.h>
64#include <netinet/if_inarp.h>
65
66#include <nfs/rpcv2.h>
67#include <nfs/krpc.h>
68#include <nfs/xdr_subs.h>
69
70#include <nfs/nfsproto.h>
71#include <nfs/nfs.h>
72#include <nfs/nfsmount.h>
73#include <nfs/nfsdiskless.h>
74
75/*
76 * There are three implementations of NFS diskless boot.
77 * One implementation uses BOOTP (RFC951, RFC1048),
78 * Sun RPC/bootparams or static configuration. See the
79 * files:
80 * nfs_bootdhcp.c: BOOTP (RFC951, RFC1048)
81 * nfs_bootparam.c: Sun RPC/bootparams
82 * nfs_bootstatic.c: honour config(1) description
83 */
84#if defined(NFS_BOOT_BOOTP) || defined(NFS_BOOT_DHCP)
85int nfs_boot_rfc951 = 1; /* BOOTP enabled (default) */
86#endif
87#ifdef NFS_BOOT_BOOTPARAM
88int nfs_boot_bootparam = 1; /* BOOTPARAM enabled (default) */
89#endif
90#ifdef NFS_BOOT_BOOTSTATIC
91int nfs_boot_bootstatic = 1; /* BOOTSTATIC enabled (default) */
92#endif
93
94#define IP_MIN_MTU 576
95
96/* mountd RPC */
97static int md_mount(struct sockaddr_in *mdsin, char *path,
98 struct nfs_args *argp, struct lwp *l);
99
100static int nfs_boot_delroute_matcher(struct rtentry *, void *);
101static void nfs_boot_defrt(struct in_addr *);
102static int nfs_boot_getfh(struct nfs_dlmount *ndm, struct lwp *);
103
104
105/*
106 * Called with an empty nfs_diskless struct to be filled in.
107 * Find an interface, determine its ip address (etc.) and
108 * save all the boot parameters in the nfs_diskless struct.
109 */
110int
111nfs_boot_init(struct nfs_diskless *nd, struct lwp *lwp)
112{
113 struct ifnet *ifp;
114 int error = 0;
115 int flags __unused;
116
117 /* Explicitly necessary or build fails
118 * due to unused variable, otherwise.
119 */
120 flags = 0;
121
122 /*
123 * Find the network interface.
124 */
125 ifp = ifunit(device_xname(root_device));
126 if (ifp == NULL) {
127 printf("nfs_boot: '%s' not found\n",
128 device_xname(root_device));
129 return (ENXIO);
130 }
131 nd->nd_ifp = ifp;
132
133 error = EADDRNOTAVAIL; /* ??? */
134#if defined(NFS_BOOT_BOOTSTATIC)
135 if (error && nfs_boot_bootstatic) {
136 printf("nfs_boot: trying static\n");
137 error = nfs_bootstatic(nd, lwp, &flags);
138 }
139#endif
140#if defined(NFS_BOOT_BOOTP) || defined(NFS_BOOT_DHCP)
141 if (error && nfs_boot_rfc951) {
142#if defined(NFS_BOOT_DHCP)
143 printf("nfs_boot: trying DHCP/BOOTP\n");
144#else
145 printf("nfs_boot: trying BOOTP\n");
146#endif
147 error = nfs_bootdhcp(nd, lwp, &flags);
148 }
149#endif
150#ifdef NFS_BOOT_BOOTPARAM
151 if (error && nfs_boot_bootparam) {
152 printf("nfs_boot: trying RARP (and RPC/bootparam)\n");
153 error = nfs_bootparam(nd, lwp, &flags);
154 }
155#endif
156 if (error)
157 return (error);
158
159 /*
160 * Set MTU if passed
161 */
162 if (nd->nd_mtu >= IP_MIN_MTU )
163 nfs_boot_setmtu(nd->nd_ifp, nd->nd_mtu, lwp);
164
165 /*
166 * If the gateway address is set, add a default route.
167 * (The mountd RPCs may go across a gateway.)
168 */
169 if (nd->nd_gwip.s_addr)
170 nfs_boot_defrt(&nd->nd_gwip);
171
172#ifdef TFTPROOT
173 if (nd->nd_nomount)
174 goto out;
175#endif
176 /*
177 * Now fetch the NFS file handles as appropriate.
178 */
179 error = nfs_boot_getfh(&nd->nd_root, lwp);
180
181 if (error)
182 nfs_boot_cleanup(nd, lwp);
183
184#ifdef TFTPROOT
185out:
186#endif
187 return (error);
188}
189
190void
191nfs_boot_cleanup(struct nfs_diskless *nd, struct lwp *lwp)
192{
193
194 nfs_boot_deladdress(nd->nd_ifp, lwp, nd->nd_myip.s_addr);
195 nfs_boot_ifupdown(nd->nd_ifp, lwp, 0);
196 nfs_boot_flushrt(nd->nd_ifp);
197}
198
199int
200nfs_boot_ifupdown(struct ifnet *ifp, struct lwp *lwp, int up)
201{
202 struct socket *so;
203 struct ifreq ireq;
204 int error;
205
206 memset(&ireq, 0, sizeof(ireq));
207 memcpy(ireq.ifr_name, ifp->if_xname, IFNAMSIZ);
208
209 /*
210 * Get a socket to use for various things in here.
211 * After this, use "goto out" to cleanup and return.
212 */
213 error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp, NULL);
214 if (error) {
215 printf("ifupdown: socreate, error=%d\n", error);
216 return (error);
217 }
218
219 /*
220 * Bring up the interface. (just set the "up" flag)
221 * Get the old interface flags and or IFF_UP into them so
222 * things like media selection flags are not clobbered.
223 */
224 error = ifioctl(so, SIOCGIFFLAGS, (void *)&ireq, lwp);
225 if (error) {
226 printf("ifupdown: GIFFLAGS, error=%d\n", error);
227 goto out;
228 }
229 if (up)
230 ireq.ifr_flags |= IFF_UP;
231 else
232 ireq.ifr_flags &= ~IFF_UP;
233 error = ifioctl(so, SIOCSIFFLAGS, &ireq, lwp);
234 if (error) {
235 printf("ifupdown: SIFFLAGS, error=%d\n", error);
236 goto out;
237 }
238
239 if (up)
240 /* give the link some time to get up */
241 tsleep(nfs_boot_ifupdown, PZERO, "nfsbif", 3 * hz);
242out:
243 soclose(so);
244 return (error);
245}
246
247void
248nfs_boot_setmtu(struct ifnet *ifp, int mtu, struct lwp *lwp)
249{
250 struct socket *so;
251 struct ifreq ireq;
252 int error;
253
254 memset(&ireq, 0, sizeof(ireq));
255 memcpy(ireq.ifr_name, ifp->if_xname, IFNAMSIZ);
256
257 /*
258 * Get a socket to use for various things in here.
259 * After this, use "goto out" to cleanup and return.
260 */
261 error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp, NULL);
262 if (error) {
263 printf("setmtu: socreate, error=%d\n", error);
264 return;
265 }
266
267 /*
268 * Get structure, set the new MTU, push structure.
269 */
270 error = ifioctl(so, SIOCGIFMTU, (void *)&ireq, lwp);
271 if (error) {
272 printf("setmtu: GIFMTU, error=%d\n", error);
273 goto out;
274 }
275
276 ireq.ifr_mtu = mtu;
277
278 error = ifioctl(so, SIOCSIFMTU, &ireq, lwp);
279 if (error) {
280 printf("setmtu: SIFMTU, error=%d\n", error);
281 goto out;
282 }
283
284out:
285 soclose(so);
286 return;
287}
288
289int
290nfs_boot_setaddress(struct ifnet *ifp, struct lwp *lwp,
291 uint32_t addr, uint32_t netmask, uint32_t braddr)
292{
293 struct socket *so;
294 struct ifaliasreq iareq;
295 struct sockaddr_in *sin;
296 int error;
297
298 /*
299 * Get a socket to use for various things in here.
300 * After this, use "goto out" to cleanup and return.
301 */
302 error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp, NULL);
303 if (error) {
304 printf("setaddress: socreate, error=%d\n", error);
305 return (error);
306 }
307
308 memset(&iareq, 0, sizeof(iareq));
309 memcpy(iareq.ifra_name, ifp->if_xname, IFNAMSIZ);
310
311 /* Set the I/F address */
312 sin = (struct sockaddr_in *)&iareq.ifra_addr;
313 sin->sin_len = sizeof(*sin);
314 sin->sin_family = AF_INET;
315 sin->sin_addr.s_addr = addr;
316
317 /* Set the netmask */
318 if (netmask != INADDR_ANY) {
319 sin = (struct sockaddr_in *)&iareq.ifra_mask;
320 sin->sin_len = sizeof(*sin);
321 sin->sin_family = AF_INET;
322 sin->sin_addr.s_addr = netmask;
323 } /* else leave subnetmask unspecified (len=0) */
324
325 /* Set the broadcast addr. */
326 if (braddr != INADDR_ANY) {
327 sin = (struct sockaddr_in *)&iareq.ifra_broadaddr;
328 sin->sin_len = sizeof(*sin);
329 sin->sin_family = AF_INET;
330 sin->sin_addr.s_addr = braddr;
331 } /* else leave broadcast addr unspecified (len=0) */
332
333 error = ifioctl(so, SIOCAIFADDR, (void *)&iareq, lwp);
334 if (error) {
335 printf("setaddress, error=%d\n", error);
336 goto out;
337 }
338
339 /* give the link some time to get up */
340 tsleep(nfs_boot_setaddress, PZERO, "nfsbtd", 3 * hz);
341out:
342 soclose(so);
343 return (error);
344}
345
346int
347nfs_boot_deladdress(struct ifnet *ifp, struct lwp *lwp, uint32_t addr)
348{
349 struct socket *so;
350 struct ifreq ifr;
351 struct sockaddr_in sin;
352 struct in_addr ia = {.s_addr = addr};
353 int error;
354
355 /*
356 * Get a socket to use for various things in here.
357 * After this, use "goto out" to cleanup and return.
358 */
359 error = socreate(AF_INET, &so, SOCK_DGRAM, 0, lwp, NULL);
360 if (error) {
361 printf("deladdress: socreate, error=%d\n", error);
362 return (error);
363 }
364
365 memset(&ifr, 0, sizeof(ifr));
366 memcpy(ifr.ifr_name, ifp->if_xname, IFNAMSIZ);
367
368 sockaddr_in_init(&sin, &ia, 0);
369 ifreq_setaddr(SIOCDIFADDR, &ifr, sintocsa(&sin));
370
371 error = ifioctl(so, SIOCDIFADDR, &ifr, lwp);
372 if (error) {
373 printf("deladdress, error=%d\n", error);
374 goto out;
375 }
376
377out:
378 soclose(so);
379 return (error);
380}
381
382int
383nfs_boot_setrecvtimo(struct socket *so)
384{
385 struct timeval tv;
386
387 tv.tv_sec = 1;
388 tv.tv_usec = 0;
389
390 return (so_setsockopt(NULL, so, SOL_SOCKET, SO_RCVTIMEO, &tv,
391 sizeof(tv)));
392}
393
394int
395nfs_boot_enbroadcast(struct socket *so)
396{
397 int32_t on;
398
399 on = 1;
400 return (so_setsockopt(NULL, so, SOL_SOCKET, SO_BROADCAST, &on,
401 sizeof(on)));
402}
403
404int
405nfs_boot_sobind_ipport(struct socket *so, uint16_t port, struct lwp *l)
406{
407 struct sockaddr_in sin;
408 int error;
409
410 sin.sin_len = sizeof(sin);
411 sin.sin_family = AF_INET;
412 sin.sin_addr.s_addr = INADDR_ANY;
413 sin.sin_port = htons(port);
414 error = sobind(so, (struct sockaddr *)&sin, l);
415 return (error);
416}
417
418/*
419 * What is the longest we will wait before re-sending a request?
420 * Note this is also the frequency of "timeout" messages.
421 * The re-send loop counts up linearly to this maximum, so the
422 * first complaint will happen after (1+2+3+4+5)=15 seconds.
423 */
424#define MAX_RESEND_DELAY 5 /* seconds */
425#define TOTAL_TIMEOUT 30 /* seconds */
426
427int
428nfs_boot_sendrecv(struct socket *so, struct sockaddr_in *nam,
429 int (*sndproc)(struct mbuf *, void *, int),
430 struct mbuf *snd,
431 int (*rcvproc)(struct mbuf **, void *),
432 struct mbuf **rcv, struct mbuf **from_p,
433 void *context, struct lwp *lwp)
434{
435 int error, rcvflg, timo, secs, waited;
436 struct mbuf *m, *from;
437 struct uio uio;
438
439 /* Free at end if not null. */
440 from = NULL;
441
442 /*
443 * Send it, repeatedly, until a reply is received,
444 * but delay each re-send by an increasing amount.
445 * If the delay hits the maximum, start complaining.
446 */
447 waited = timo = 0;
448send_again:
449 waited += timo;
450 if (waited >= TOTAL_TIMEOUT)
451 return (ETIMEDOUT);
452
453 /* Determine new timeout. */
454 if (timo < MAX_RESEND_DELAY)
455 timo++;
456 else
457 printf("nfs_boot: timeout...\n");
458
459 if (sndproc) {
460 error = (*sndproc)(snd, context, waited);
461 if (error)
462 goto out;
463 }
464
465 /* Send request (or re-send). */
466 m = m_copypacket(snd, M_WAIT);
467 if (m == NULL) {
468 error = ENOBUFS;
469 goto out;
470 }
471 error = (*so->so_send)(so, (struct sockaddr *)nam, NULL,
472 m, NULL, 0, lwp);
473 if (error) {
474 printf("nfs_boot: sosend: %d\n", error);
475 goto out;
476 }
477 m = NULL;
478
479 /*
480 * Wait for up to timo seconds for a reply.
481 * The socket receive timeout was set to 1 second.
482 */
483
484 secs = timo;
485 for (;;) {
486 if (from) {
487 m_freem(from);
488 from = NULL;
489 }
490 if (m) {
491 m_freem(m);
492 m = NULL;
493 }
494 uio.uio_resid = 1 << 16; /* ??? */
495 rcvflg = 0;
496 error = (*so->so_receive)(so, &from, &uio, &m, NULL, &rcvflg);
497 if (error == EWOULDBLOCK) {
498 if (--secs <= 0)
499 goto send_again;
500 continue;
501 }
502 if (error)
503 goto out;
504#ifdef DIAGNOSTIC
505 if (!m || !(m->m_flags & M_PKTHDR)
506 || (1 << 16) - uio.uio_resid != m->m_pkthdr.len)
507 panic("nfs_boot_sendrecv: return size");
508#endif
509
510 if ((*rcvproc)(&m, context))
511 continue;
512
513 if (rcv)
514 *rcv = m;
515 else
516 m_freem(m);
517 if (from_p) {
518 *from_p = from;
519 from = NULL;
520 }
521 break;
522 }
523out:
524 if (from) m_freem(from);
525 return (error);
526}
527
528/*
529 * Install a default route to the passed IP address.
530 */
531static void
532nfs_boot_defrt(struct in_addr *gw_ip)
533{
534 struct sockaddr dst, gw, mask;
535 struct sockaddr_in *sin;
536 int error;
537
538 /* Destination: (default) */
539 memset((void *)&dst, 0, sizeof(dst));
540 dst.sa_len = sizeof(dst);
541 dst.sa_family = AF_INET;
542 /* Gateway: */
543 memset((void *)&gw, 0, sizeof(gw));
544 sin = (struct sockaddr_in *)&gw;
545 sin->sin_len = sizeof(*sin);
546 sin->sin_family = AF_INET;
547 sin->sin_addr.s_addr = gw_ip->s_addr;
548 /* Mask: (zero length) */
549 /* XXX - Just pass a null pointer? */
550 memset(&mask, 0, sizeof(mask));
551
552 /* add, dest, gw, mask, flags, 0 */
553 error = rtrequest(RTM_ADD, &dst, &gw, &mask,
554 (RTF_UP | RTF_GATEWAY | RTF_STATIC), NULL);
555 if (error) {
556 printf("nfs_boot: add route, error=%d\n", error);
557 error = 0;
558 }
559}
560
561static int
562nfs_boot_delroute_matcher(struct rtentry *rt, void *w)
563{
564
565 if ((void *)rt->rt_ifp != w)
566 return 0;
567
568 return 1;
569}
570
571void
572nfs_boot_flushrt(struct ifnet *ifp)
573{
574
575 rt_delete_matched_entries(AF_INET, nfs_boot_delroute_matcher, ifp);
576}
577
578/*
579 * Get an initial NFS file handle using Sun RPC/mountd.
580 * Separate function because we used to call it twice.
581 * (once for root and once for swap)
582 *
583 * ndm output
584 */
585static int
586nfs_boot_getfh(struct nfs_dlmount *ndm, struct lwp *l)
587{
588 struct nfs_args *args;
589 struct sockaddr_in *sin;
590 char *pathname;
591 int error;
592 u_int16_t port;
593
594 args = &ndm->ndm_args;
595
596 /* Initialize mount args. */
597 memset((void *) args, 0, sizeof(*args));
598 args->addr = &ndm->ndm_saddr;
599 args->addrlen = args->addr->sa_len;
600#ifdef NFS_BOOT_TCP
601 args->sotype = SOCK_STREAM;
602#else
603 args->sotype = SOCK_DGRAM;
604#endif
605 args->fh = ndm->ndm_fh;
606 args->hostname = ndm->ndm_host;
607 args->flags = NFSMNT_NOCONN | NFSMNT_RESVPORT;
608
609#ifndef NFS_V2_ONLY
610 args->flags |= NFSMNT_NFSV3;
611#endif
612#ifdef NFS_BOOT_OPTIONS
613 args->flags |= NFS_BOOT_OPTIONS;
614#endif
615#ifdef NFS_BOOT_RWSIZE
616 /*
617 * Reduce rsize,wsize for interfaces that consistently
618 * drop fragments of long UDP messages. (i.e. wd8003).
619 * You can always change these later via remount.
620 */
621 args->flags |= NFSMNT_WSIZE | NFSMNT_RSIZE;
622 args->wsize = NFS_BOOT_RWSIZE;
623 args->rsize = NFS_BOOT_RWSIZE;
624#endif
625
626 /*
627 * Find the pathname part of the "server:pathname"
628 * string left in ndm->ndm_host by nfs_boot_init.
629 */
630 pathname = strchr(ndm->ndm_host, ':');
631 if (pathname == 0) {
632 printf("nfs_boot: getfh - no pathname\n");
633 return (EIO);
634 }
635 pathname++;
636
637 /*
638 * Get file handle using RPC to mountd/mount
639 */
640 sin = (struct sockaddr_in *)&ndm->ndm_saddr;
641 error = md_mount(sin, pathname, args, l);
642 if (error) {
643 printf("nfs_boot: mountd `%s', error=%d\n",
644 ndm->ndm_host, error);
645 return (error);
646 }
647
648 /* Set port number for NFS use. */
649 /* XXX: NFS port is always 2049, right? */
650retry:
651 error = krpc_portmap(sin, NFS_PROG,
652 (args->flags & NFSMNT_NFSV3) ? NFS_VER3 : NFS_VER2,
653 (args->sotype == SOCK_STREAM) ? IPPROTO_TCP : IPPROTO_UDP,
654 &port, l);
655 if (port == htons(0))
656 error = EIO;
657 if (error) {
658 if (args->sotype == SOCK_STREAM) {
659 args->sotype = SOCK_DGRAM;
660 goto retry;
661 }
662 printf("nfs_boot: portmap NFS, error=%d\n", error);
663 return (error);
664 }
665 sin->sin_port = port;
666 return (0);
667}
668
669
670/*
671 * RPC: mountd/mount
672 * Given a server pathname, get an NFS file handle.
673 * Also, sets sin->sin_port to the NFS service port.
674 *
675 * mdsin mountd server address
676 */
677static int
678md_mount(struct sockaddr_in *mdsin, char *path,
679 struct nfs_args *argp, struct lwp *lwp)
680{
681 /* The RPC structures */
682 struct rdata {
683 u_int32_t errno;
684 union {
685 u_int8_t v2fh[NFSX_V2FH];
686 struct {
687 u_int32_t fhlen;
688 u_int8_t fh[1];
689 } v3fh;
690 } fh;
691 } *rdata;
692 struct mbuf *m;
693 u_int8_t *fh;
694 int minlen, error;
695 int mntver;
696
697 mntver = (argp->flags & NFSMNT_NFSV3) ? 3 : 2;
698 do {
699 /*
700 * Get port number for MOUNTD.
701 */
702 error = krpc_portmap(mdsin, RPCPROG_MNT, mntver,
703 IPPROTO_UDP, &mdsin->sin_port, lwp);
704 if (error)
705 continue;
706
707 /* This mbuf is consumed by krpc_call. */
708 m = xdr_string_encode(path, strlen(path));
709 if (m == NULL)
710 return ENOMEM;
711
712 /* Do RPC to mountd. */
713 error = krpc_call(mdsin, RPCPROG_MNT, mntver,
714 RPCMNT_MOUNT, &m, NULL, lwp);
715 if (error != EPROGMISMATCH)
716 break;
717 /* Try lower version of mountd. */
718 } while (--mntver >= 1);
719 if (error) {
720 printf("nfs_boot: mountd error=%d\n", error);
721 return error;
722 }
723 if (mntver != 3)
724 argp->flags &= ~NFSMNT_NFSV3;
725
726 /* The reply might have only the errno. */
727 if (m->m_len < 4)
728 goto bad;
729 /* Have at least errno, so check that. */
730 rdata = mtod(m, struct rdata *);
731 error = fxdr_unsigned(u_int32_t, rdata->errno);
732 if (error)
733 goto out;
734
735 /* Have errno==0, so the fh must be there. */
736 if (mntver == 3) {
737 argp->fhsize = fxdr_unsigned(u_int32_t, rdata->fh.v3fh.fhlen);
738 if (argp->fhsize > NFSX_V3FHMAX)
739 goto bad;
740 minlen = 2 * sizeof(u_int32_t) + argp->fhsize;
741 } else {
742 argp->fhsize = NFSX_V2FH;
743 minlen = sizeof(u_int32_t) + argp->fhsize;
744 }
745
746 if (m->m_len < minlen) {
747 m = m_pullup(m, minlen);
748 if (m == NULL)
749 return(EBADRPC);
750 rdata = mtod(m, struct rdata *);
751 }
752
753 fh = (mntver == 3) ?
754 rdata->fh.v3fh.fh : rdata->fh.v2fh;
755 memcpy(argp->fh, fh, argp->fhsize);
756
757 goto out;
758
759bad:
760 error = EBADRPC;
761
762out:
763 m_freem(m);
764 return error;
765}
766