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nfs_boot.c revision 1.29
      1 /*	$NetBSD: nfs_boot.c,v 1.29 1996/10/20 13:13:25 fvdl Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995 Adam Glass, Gordon Ross
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. The name of the authors may not be used to endorse or promote products
     16  *    derived from this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
     19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     21  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 #include <sys/param.h>
     31 #include <sys/systm.h>
     32 #include <sys/kernel.h>
     33 #include <sys/conf.h>
     34 #include <sys/ioctl.h>
     35 #include <sys/proc.h>
     36 #include <sys/mount.h>
     37 #include <sys/mbuf.h>
     38 #include <sys/reboot.h>
     39 #include <sys/socket.h>
     40 #include <sys/socketvar.h>
     41 
     42 #include <net/if.h>
     43 #include <net/route.h>
     44 
     45 #include <netinet/in.h>
     46 #include <netinet/if_ether.h>
     47 
     48 #include <nfs/rpcv2.h>
     49 #include <nfs/nfsproto.h>
     50 #include <nfs/nfs.h>
     51 #include <nfs/nfsdiskless.h>
     52 #include <nfs/krpc.h>
     53 #include <nfs/xdr_subs.h>
     54 #include <nfs/nfs_var.h>
     55 
     56 #include "ether.h"
     57 #if NETHER == 0
     58 
     59 int nfs_boot_init(nd, procp)
     60 	struct nfs_diskless *nd;
     61 	struct proc *procp;
     62 {
     63 	panic("nfs_boot_init: no ether");
     64 }
     65 
     66 void
     67 nfs_boot_getfh(bpsin, key, ndmntp)
     68 	struct sockaddr_in *bpsin;
     69 	char *key;
     70 	struct nfs_dlmount *ndmntp;
     71 {
     72 	/* can not get here */
     73 }
     74 
     75 #else /* NETHER */
     76 
     77 /*
     78  * Support for NFS diskless booting, specifically getting information
     79  * about where to boot from, what pathnames, etc.
     80  *
     81  * This implememtation uses RARP and the bootparam RPC.
     82  * We are forced to implement RPC anyway (to get file handles)
     83  * so we might as well take advantage of it for bootparam too.
     84  *
     85  * The diskless boot sequence goes as follows:
     86  * (1) Use RARP to get our interface address
     87  * (2) Use RPC/bootparam/whoami to get our hostname,
     88  *     our IP address, and the server's IP address.
     89  * (3) Use RPC/bootparam/getfile to get the root path
     90  * (4) Use RPC/mountd to get the root file handle
     91  * (5) Use RPC/bootparam/getfile to get the swap path
     92  * (6) Use RPC/mountd to get the swap file handle
     93  *
     94  * (This happens to be the way Sun does it too.)
     95  */
     96 
     97 /* bootparam RPC */
     98 static int bp_whoami __P((struct sockaddr_in *bpsin,
     99 	struct in_addr *my_ip, struct in_addr *gw_ip));
    100 static int bp_getfile __P((struct sockaddr_in *bpsin, char *key,
    101 	struct sockaddr_in *mdsin, char *servname, char *path));
    102 
    103 /* mountd RPC */
    104 static int md_mount __P((struct sockaddr_in *mdsin, char *path,
    105 	struct nfs_args *argp));
    106 
    107 char	*nfsbootdevname;
    108 
    109 /*
    110  * Called with an empty nfs_diskless struct to be filled in.
    111  */
    112 int
    113 nfs_boot_init(nd, procp)
    114 	struct nfs_diskless *nd;
    115 	struct proc *procp;
    116 {
    117 	struct ifreq ireq;
    118 	struct in_addr my_ip, gw_ip;
    119 	struct sockaddr_in bp_sin;
    120 	struct sockaddr_in *sin;
    121 	struct ifnet *ifp;
    122 	struct socket *so;
    123 	int error;
    124 
    125 	/*
    126 	 * Find an interface, rarp for its ip address, stuff it, the
    127 	 * implied broadcast addr, and netmask into a nfs_diskless struct.
    128 	 *
    129 	 * This was moved here from nfs_vfsops.c because this procedure
    130 	 * would be quite different if someone decides to write (i.e.) a
    131 	 * BOOTP version of this file (might not use RARP, etc.)
    132 	 */
    133 
    134 	/*
    135 	 * Find a network interface.
    136 	 */
    137 	if (nfsbootdevname)
    138 		ifp = ifunit(nfsbootdevname);
    139 	else
    140 		for (ifp = ifnet.tqh_first; ifp != 0; ifp = ifp->if_list.tqe_next)
    141 			if ((ifp->if_flags &
    142 			     (IFF_LOOPBACK|IFF_POINTOPOINT)) == 0)
    143 				break;
    144 	if (ifp == NULL)
    145 		panic("nfs_boot: no suitable interface");
    146 	bcopy(ifp->if_xname, ireq.ifr_name, IFNAMSIZ);
    147 	printf("nfs_boot: using network interface '%s'\n",
    148 	    ireq.ifr_name);
    149 
    150 	/*
    151 	 * Bring up the interface.
    152 	 *
    153 	 * Get the old interface flags and or IFF_UP into them; if
    154 	 * IFF_UP set blindly, interface selection can be clobbered.
    155 	 */
    156 	if ((error = socreate(AF_INET, &so, SOCK_DGRAM, 0)) != 0)
    157 		panic("nfs_boot: socreate, error=%d", error);
    158 	error = ifioctl(so, SIOCGIFFLAGS, (caddr_t)&ireq, procp);
    159 	if (error)
    160 		panic("nfs_boot: GIFFLAGS, error=%d", error);
    161 	ireq.ifr_flags |= IFF_UP;
    162 	error = ifioctl(so, SIOCSIFFLAGS, (caddr_t)&ireq, procp);
    163 	if (error)
    164 		panic("nfs_boot: SIFFLAGS, error=%d", error);
    165 
    166 	/*
    167 	 * Do RARP for the interface address.
    168 	 */
    169 	if ((error = revarpwhoami(&my_ip, ifp)) != 0)
    170 		panic("revarp failed, error=%d", error);
    171 	printf("nfs_boot: client_addr=0x%x\n", (u_int32_t)ntohl(my_ip.s_addr));
    172 
    173 	/*
    174 	 * Do enough of ifconfig(8) so that the chosen interface
    175 	 * can talk to the servers.  (just set the address)
    176 	 */
    177 	sin = (struct sockaddr_in *)&ireq.ifr_addr;
    178 	bzero((caddr_t)sin, sizeof(*sin));
    179 	sin->sin_len = sizeof(*sin);
    180 	sin->sin_family = AF_INET;
    181 	sin->sin_addr.s_addr = my_ip.s_addr;
    182 	error = ifioctl(so, SIOCSIFADDR, (caddr_t)&ireq, procp);
    183 	if (error)
    184 		panic("nfs_boot: set if addr, error=%d", error);
    185 
    186 	soclose(so);
    187 
    188 	/*
    189 	 * Get client name and gateway address.
    190 	 * RPC: bootparam/whoami
    191 	 * Use the old broadcast address for the WHOAMI
    192 	 * call because we do not yet know our netmask.
    193 	 * The server address returned by the WHOAMI call
    194 	 * is used for all subsequent booptaram RPCs.
    195 	 */
    196 	bzero((caddr_t)&bp_sin, sizeof(bp_sin));
    197 	bp_sin.sin_len = sizeof(bp_sin);
    198 	bp_sin.sin_family = AF_INET;
    199 	bp_sin.sin_addr.s_addr = INADDR_BROADCAST;
    200 	hostnamelen = MAXHOSTNAMELEN;
    201 
    202 	/* this returns gateway IP address */
    203 	error = bp_whoami(&bp_sin, &my_ip, &gw_ip);
    204 	if (error)
    205 		panic("nfs_boot: bootparam whoami, error=%d", error);
    206 	printf("nfs_boot: server_addr=0x%x\n",
    207 		   (u_int32_t)ntohl(bp_sin.sin_addr.s_addr));
    208 	printf("nfs_boot: hostname=%s\n", hostname);
    209 
    210 #ifdef	NFS_BOOT_GATEWAY
    211 	/*
    212 	 * XXX - This code is conditionally compiled only because
    213 	 * many bootparam servers (in particular, SunOS 4.1.3)
    214 	 * always set the gateway address to their own address.
    215 	 * The bootparam server is not necessarily the gateway.
    216 	 * We could just believe the server, and at worst you would
    217 	 * need to delete the incorrect default route before adding
    218 	 * the correct one, but for simplicity, ignore the gateway.
    219 	 * If your server is OK, you can turn on this option.
    220 	 *
    221 	 * If the gateway address is set, add a default route.
    222 	 * (The mountd RPCs may go across a gateway.)
    223 	 */
    224 	if (gw_ip.s_addr) {
    225 		struct sockaddr dst, gw, mask;
    226 		/* Destination: (default) */
    227 		bzero((caddr_t)&dst, sizeof(dst));
    228 		dst.sa_len = sizeof(dst);
    229 		dst.sa_family = AF_INET;
    230 		/* Gateway: */
    231 		bzero((caddr_t)&gw, sizeof(gw));
    232 		sin = (struct sockaddr_in *)&gw;
    233 		sin->sin_len = sizeof(gw);
    234 		sin->sin_family = AF_INET;
    235 		sin->sin_addr.s_addr = gw_ip.s_addr;
    236 		/* Mask: (zero length) */
    237 		bzero(&mask, sizeof(mask));
    238 
    239 		printf("nfs_boot: gateway=0x%x\n", ntohl(gw_ip.s_addr));
    240 		/* add, dest, gw, mask, flags, 0 */
    241 		error = rtrequest(RTM_ADD, &dst, (struct sockaddr *)&gw,
    242 		    &mask, (RTF_UP | RTF_GATEWAY | RTF_STATIC), NULL);
    243 		if (error)
    244 			printf("nfs_boot: add route, error=%d\n", error);
    245 	}
    246 #endif
    247 
    248 	bcopy(&bp_sin, &nd->nd_boot, sizeof(bp_sin));
    249 
    250 	return (0);
    251 }
    252 
    253 void
    254 nfs_boot_getfh(bpsin, key, ndmntp)
    255 	struct sockaddr_in *bpsin;	/* bootparam server */
    256 	char *key;			/* root or swap */
    257 	struct nfs_dlmount *ndmntp;	/* output */
    258 {
    259 	struct nfs_args *args;
    260 	char pathname[MAXPATHLEN];
    261 	char *sp, *dp, *endp;
    262 	struct sockaddr_in *sin;
    263 	int error;
    264 
    265 	args = &ndmntp->ndm_args;
    266 
    267 	/* Initialize mount args. */
    268 	bzero((caddr_t) args, sizeof(*args));
    269 	args->addr     = &ndmntp->ndm_saddr;
    270 	args->addrlen  = args->addr->sa_len;
    271 #ifdef NFS_BOOT_TCP
    272 	args->sotype   = SOCK_STREAM;
    273 #else
    274 	args->sotype   = SOCK_DGRAM;
    275 #endif
    276 	args->fh       = ndmntp->ndm_fh;
    277 	args->hostname = ndmntp->ndm_host;
    278 	args->flags    = NFSMNT_RESVPORT | NFSMNT_NFSV3;
    279 
    280 #ifdef	NFS_BOOT_OPTIONS
    281 	args->flags    |= NFS_BOOT_OPTIONS;
    282 #endif
    283 #ifdef	NFS_BOOT_RWSIZE
    284 	/*
    285 	 * Reduce rsize,wsize for interfaces that consistently
    286 	 * drop fragments of long UDP messages.  (i.e. wd8003).
    287 	 * You can always change these later via remount.
    288 	 */
    289 	args->flags   |= NFSMNT_WSIZE | NFSMNT_RSIZE;
    290 	args->wsize    = NFS_BOOT_RWSIZE;
    291 	args->rsize    = NFS_BOOT_RWSIZE;
    292 #endif
    293 
    294 	sin = (void*)&ndmntp->ndm_saddr;
    295 
    296 	/*
    297 	 * Get server:pathname for "key" (root or swap)
    298 	 * using RPC to bootparam/getfile
    299 	 */
    300 	error = bp_getfile(bpsin, key, sin, ndmntp->ndm_host, pathname);
    301 	if (error)
    302 		panic("nfs_boot: bootparam get %s: %d", key, error);
    303 
    304 	/*
    305 	 * Get file handle for "key" (root or swap)
    306 	 * using RPC to mountd/mount
    307 	 */
    308 	error = md_mount(sin, pathname, args);
    309 	if (error)
    310 		panic("nfs_boot: mountd %s, error=%d", key, error);
    311 
    312 	/* Set port number for NFS use. */
    313 	/* XXX: NFS port is always 2049, right? */
    314 #ifdef NFS_BOOT_TCP
    315 retry:
    316 #endif
    317 	error = krpc_portmap(sin, NFS_PROG,
    318 		    (args->flags & NFSMNT_NFSV3) ? NFS_VER3 : NFS_VER2,
    319 		    (args->sotype == SOCK_STREAM) ? IPPROTO_TCP : IPPROTO_UDP,
    320 		    &sin->sin_port);
    321 
    322 	if (error || (sin->sin_port == htons(0))) {
    323 #ifdef NFS_BOOT_TCP
    324 		if (args->sotype == SOCK_STREAM) {
    325 			args->sotype = SOCK_DGRAM;
    326 			goto retry;
    327 		}
    328 #endif
    329 		panic("nfs_boot: portmap NFS, error=%d", error);
    330 	}
    331 
    332 	/* Construct remote path (for getmntinfo(3)) */
    333 	dp = ndmntp->ndm_host;
    334 	endp = dp + MNAMELEN - 1;
    335 	dp += strlen(dp);
    336 	*dp++ = ':';
    337 	for (sp = pathname; *sp && dp < endp;)
    338 		*dp++ = *sp++;
    339 	*dp = '\0';
    340 
    341 }
    342 
    343 
    344 /*
    345  * RPC: bootparam/whoami
    346  * Given client IP address, get:
    347  *	client name	(hostname)
    348  *	domain name (domainname)
    349  *	gateway address
    350  *
    351  * The hostname and domainname are set here for convenience.
    352  *
    353  * Note - bpsin is initialized to the broadcast address,
    354  * and will be replaced with the bootparam server address
    355  * after this call is complete.  Have to use PMAP_PROC_CALL
    356  * to make sure we get responses only from a servers that
    357  * know about us (don't want to broadcast a getport call).
    358  */
    359 static int
    360 bp_whoami(bpsin, my_ip, gw_ip)
    361 	struct sockaddr_in *bpsin;
    362 	struct in_addr *my_ip;
    363 	struct in_addr *gw_ip;
    364 {
    365 	/* RPC structures for PMAPPROC_CALLIT */
    366 	struct whoami_call {
    367 		u_int32_t call_prog;
    368 		u_int32_t call_vers;
    369 		u_int32_t call_proc;
    370 		u_int32_t call_arglen;
    371 	} *call;
    372 	struct callit_reply {
    373 		u_int32_t port;
    374 		u_int32_t encap_len;
    375 		/* encapsulated data here */
    376 	} *reply;
    377 
    378 	struct mbuf *m, *from;
    379 	struct sockaddr_in *sin;
    380 	int error, msg_len;
    381 	int16_t port;
    382 
    383 	/*
    384 	 * Build request message for PMAPPROC_CALLIT.
    385 	 */
    386 	m = m_get(M_WAIT, MT_DATA);
    387 	call = mtod(m, struct whoami_call *);
    388 	m->m_len = sizeof(*call);
    389 	call->call_prog = txdr_unsigned(BOOTPARAM_PROG);
    390 	call->call_vers = txdr_unsigned(BOOTPARAM_VERS);
    391 	call->call_proc = txdr_unsigned(BOOTPARAM_WHOAMI);
    392 
    393 	/*
    394 	 * append encapsulated data (client IP address)
    395 	 */
    396 	m->m_next = xdr_inaddr_encode(my_ip);
    397 	call->call_arglen = txdr_unsigned(m->m_next->m_len);
    398 
    399 	/* RPC: portmap/callit */
    400 	bpsin->sin_port = htons(PMAPPORT);
    401 	from = NULL;
    402 	error = krpc_call(bpsin, PMAPPROG, PMAPVERS,
    403 			PMAPPROC_CALLIT, &m, &from);
    404 	if (error)
    405 		return error;
    406 
    407 	/*
    408 	 * Parse result message.
    409 	 */
    410 	if (m->m_len < sizeof(*reply)) {
    411 		m = m_pullup(m, sizeof(*reply));
    412 		if (m == NULL)
    413 			goto bad;
    414 	}
    415 	reply = mtod(m, struct callit_reply *);
    416 	port = fxdr_unsigned(u_int32_t, reply->port);
    417 	msg_len = fxdr_unsigned(u_int32_t, reply->encap_len);
    418 	m_adj(m, sizeof(*reply));
    419 
    420 	/*
    421 	 * Save bootparam server address
    422 	 */
    423 	sin = mtod(from, struct sockaddr_in *);
    424 	bpsin->sin_port = htons(port);
    425 	bpsin->sin_addr.s_addr = sin->sin_addr.s_addr;
    426 
    427 	/* client name */
    428 	hostnamelen = MAXHOSTNAMELEN-1;
    429 	m = xdr_string_decode(m, hostname, &hostnamelen);
    430 	if (m == NULL)
    431 		goto bad;
    432 
    433 	/* domain name */
    434 	domainnamelen = MAXHOSTNAMELEN-1;
    435 	m = xdr_string_decode(m, domainname, &domainnamelen);
    436 	if (m == NULL)
    437 		goto bad;
    438 
    439 	/* gateway address */
    440 	m = xdr_inaddr_decode(m, gw_ip);
    441 	if (m == NULL)
    442 		goto bad;
    443 
    444 	/* success */
    445 	goto out;
    446 
    447 bad:
    448 	printf("nfs_boot: bootparam_whoami: bad reply\n");
    449 	error = EBADRPC;
    450 
    451 out:
    452 	if (from)
    453 		m_freem(from);
    454 	if (m)
    455 		m_freem(m);
    456 	return(error);
    457 }
    458 
    459 
    460 /*
    461  * RPC: bootparam/getfile
    462  * Given client name and file "key", get:
    463  *	server name
    464  *	server IP address
    465  *	server pathname
    466  */
    467 static int
    468 bp_getfile(bpsin, key, md_sin, serv_name, pathname)
    469 	struct sockaddr_in *bpsin;
    470 	char *key;
    471 	struct sockaddr_in *md_sin;
    472 	char *serv_name;
    473 	char *pathname;
    474 {
    475 	struct mbuf *m;
    476 	struct sockaddr_in *sin;
    477 	struct in_addr inaddr;
    478 	int error, sn_len, path_len;
    479 
    480 	/*
    481 	 * Build request message.
    482 	 */
    483 
    484 	/* client name (hostname) */
    485 	m  = xdr_string_encode(hostname, hostnamelen);
    486 	if (m == NULL)
    487 		return (ENOMEM);
    488 
    489 	/* key name (root or swap) */
    490 	m->m_next = xdr_string_encode(key, strlen(key));
    491 	if (m->m_next == NULL)
    492 		return (ENOMEM);
    493 
    494 	/* RPC: bootparam/getfile */
    495 	error = krpc_call(bpsin, BOOTPARAM_PROG, BOOTPARAM_VERS,
    496 			BOOTPARAM_GETFILE, &m, NULL);
    497 	if (error)
    498 		return error;
    499 
    500 	/*
    501 	 * Parse result message.
    502 	 */
    503 
    504 	/* server name */
    505 	sn_len = MNAMELEN-1;
    506 	m = xdr_string_decode(m, serv_name, &sn_len);
    507 	if (m == NULL)
    508 		goto bad;
    509 
    510 	/* server IP address (mountd/NFS) */
    511 	m = xdr_inaddr_decode(m, &inaddr);
    512 	if (m == NULL)
    513 		goto bad;
    514 
    515 	/* server pathname */
    516 	path_len = MAXPATHLEN-1;
    517 	m = xdr_string_decode(m, pathname, &path_len);
    518 	if (m == NULL)
    519 		goto bad;
    520 
    521 	/* setup server socket address */
    522 	sin = md_sin;
    523 	bzero((caddr_t)sin, sizeof(*sin));
    524 	sin->sin_len = sizeof(*sin);
    525 	sin->sin_family = AF_INET;
    526 	sin->sin_addr = inaddr;
    527 
    528 	/* success */
    529 	goto out;
    530 
    531 bad:
    532 	printf("nfs_boot: bootparam_getfile: bad reply\n");
    533 	error = EBADRPC;
    534 
    535 out:
    536 	m_freem(m);
    537 	return(0);
    538 }
    539 
    540 
    541 /*
    542  * RPC: mountd/mount
    543  * Given a server pathname, get an NFS file handle.
    544  * Also, sets sin->sin_port to the NFS service port.
    545  */
    546 static int
    547 md_mount(mdsin, path, argp)
    548 	struct sockaddr_in *mdsin;		/* mountd server address */
    549 	char *path;
    550 	struct nfs_args *argp;
    551 {
    552 	/* The RPC structures */
    553 	struct rdata {
    554 		u_int32_t errno;
    555 		union {
    556 			u_int8_t  v2fh[NFSX_V2FH];
    557 			struct {
    558 				u_int32_t fhlen;
    559 				u_int8_t  fh[1];
    560 			} v3fh;
    561 		} fh;
    562 	} *rdata;
    563 	struct mbuf *m;
    564 	u_int8_t *fh;
    565 	int minlen, error;
    566 
    567 retry:
    568 	/* Get port number for MOUNTD. */
    569 	error = krpc_portmap(mdsin, RPCPROG_MNT,
    570 		     (argp->flags & NFSMNT_NFSV3) ? RPCMNT_VER3 : RPCMNT_VER1,
    571 		     IPPROTO_UDP, &mdsin->sin_port);
    572 	if (error)
    573 		return error;
    574 
    575 	m = xdr_string_encode(path, strlen(path));
    576 	if (m == NULL)
    577 		return ENOMEM;
    578 
    579 	/* Do RPC to mountd. */
    580 	error = krpc_call(mdsin, RPCPROG_MNT, (argp->flags & NFSMNT_NFSV3) ?
    581 			  RPCMNT_VER3 : RPCMNT_VER1, RPCMNT_MOUNT, &m, NULL);
    582 	if (error) {
    583 		if ((error==RPC_PROGMISMATCH) && (argp->flags & NFSMNT_NFSV3)) {
    584 			argp->flags &= ~NFSMNT_NFSV3;
    585 			goto retry;
    586 		}
    587 		return error;	/* message already freed */
    588 	}
    589 
    590 	/* The reply might have only the errno. */
    591 	if (m->m_len < 4)
    592 		goto bad;
    593 	/* Have at least errno, so check that. */
    594 	rdata = mtod(m, struct rdata *);
    595 	error = fxdr_unsigned(u_int32_t, rdata->errno);
    596 	if (error)
    597 		goto out;
    598 
    599 	 /* Have errno==0, so the fh must be there. */
    600 	if (argp->flags & NFSMNT_NFSV3){
    601 		argp->fhsize   = fxdr_unsigned(u_int32_t, rdata->fh.v3fh.fhlen);
    602 		if (argp->fhsize > NFSX_V3FHMAX)
    603 			goto bad;
    604 		minlen = 2 * sizeof(u_int32_t) + argp->fhsize;
    605 	} else {
    606 		argp->fhsize   = NFSX_V2FH;
    607 		minlen = sizeof(u_int32_t) + argp->fhsize;
    608 	}
    609 
    610 	if (m->m_len < minlen) {
    611 		m = m_pullup(m, minlen);
    612 		if (m == NULL)
    613 			return(EBADRPC);
    614 		rdata = mtod(m, struct rdata *);
    615 	}
    616 
    617 	fh = (argp->flags & NFSMNT_NFSV3) ? rdata->fh.v3fh.fh : rdata->fh.v2fh;
    618 	bcopy(fh, argp->fh, argp->fhsize);
    619 
    620 	goto out;
    621 
    622 bad:
    623 	error = EBADRPC;
    624 
    625 out:
    626 	m_freem(m);
    627 	return error;
    628 }
    629 
    630 #endif /* NETHER */
    631