utils/mount/network.c

   1 /*
   2  * network.c -- Provide common network functions for NFS mount/umount
   3  *
   4  * Copyright (C) 2007 Oracle.  All rights reserved.
   5  * Copyright (C) 2007 Chuck Lever <chuck.lever@oracle.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public
  18  * License along with this program; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20  * Boston, MA 021110-1307, USA.
  21  *
  22  */
  23
  24 #include <ctype.h>
  25 #include <unistd.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <stdlib.h>
  29 #include <errno.h>
  30 #include <netdb.h>
  31 #include <time.h>
  32 #include <rpc/rpc.h>
  33 #include <rpc/pmap_prot.h>
  34 #include <rpc/pmap_clnt.h>
  35 #include <sys/socket.h>
  36
  37 #include "conn.h"
  38 #include "xcommon.h"
  39 #include "mount.h"
  40 #include "nls.h"
  41 #include "nfs_mount.h"
  42 #include "mount_constants.h"
  43 #include "network.h"
  44
  45 #ifdef HAVE_RPCSVC_NFS_PROT_H
  46 #include <rpcsvc/nfs_prot.h>
  47 #else
  48 #include <linux/nfs.h>
  49 #define nfsstat nfs_stat
  50 #endif
  51
  52 #ifndef NFS_PORT
  53 #define NFS_PORT 2049
  54 #endif
  55
  56 extern int nfs_mount_data_version;
  57 extern char *progname;
  58 extern int verbose;
  59
  60 static const unsigned int probe_udp_only[] = {
  61         IPPROTO_UDP,
  62         0,
  63 };
  64
  65 static const unsigned int probe_udp_first[] = {
  66         IPPROTO_UDP,
  67         IPPROTO_TCP,
  68         0,
  69 };
  70
  71 static const unsigned int probe_tcp_first[] = {
  72         IPPROTO_TCP,
  73         IPPROTO_UDP,
  74         0,
  75 };
  76
  77 static const unsigned long probe_nfs2_only[] = {
  78         2,
  79         0,
  80 };
  81
  82 static const unsigned long probe_nfs3_first[] = {
  83         3,
  84         2,
  85         0,
  86 };
  87
  88 static const unsigned long probe_mnt1_first[] = {
  89         1,
  90         2,
  91         0,
  92 };
  93
  94 static const unsigned long probe_mnt3_first[] = {
  95         3,
  96         1,
  97         2,
  98         0,
  99 };
 100
 101 int nfs_gethostbyname(const char *hostname, struct sockaddr_in *saddr)
 102 {
 103         struct hostent *hp;
 104
 105         saddr->sin_family = AF_INET;
 106         if (!inet_aton(hostname, &saddr->sin_addr)) {
 107                 if ((hp = gethostbyname(hostname)) == NULL) {
 108                         nfs_error(_("%s: can't get address for %s\n"),
 109                                         progname, hostname);
 110                         return 0;
 111                 } else {
 112                         if (hp->h_length > sizeof(*saddr)) {
 113                                 nfs_error(_("%s: got bad hp->h_length\n"),
 114                                                 progname);
 115                                 hp->h_length = sizeof(*saddr);
 116                         }
 117                         memcpy(&saddr->sin_addr, hp->h_addr, hp->h_length);
 118                 }
 119         }
 120         return 1;
 121 }
 122
 123 /*
 124  * getport() is very similar to pmap_getport() with the exception that
 125  * this version tries to use an ephemeral port, since reserved ports are
 126  * not needed for GETPORT queries.  This conserves the very limited
 127  * reserved port space, which helps reduce failed socket binds
 128  * during mount storms.
 129  *
 130  * A side effect of calling this function is that rpccreateerr is set.
 131  */
 132 static unsigned short getport(struct sockaddr_in *saddr,
 133                                 unsigned long program,
 134                                 unsigned long version,
 135                                 unsigned int proto)
 136 {
 137         unsigned short port = 0;
 138         int socket;
 139         CLIENT *clnt = NULL;
 140         enum clnt_stat stat;
 141
 142         saddr->sin_port = htons(PMAPPORT);
 143
 144         /*
 145          * Try to get a socket with a non-privileged port.
 146          * clnt*create() will create one anyway if this
 147          * fails.
 148          */
 149         socket = get_socket(saddr, proto, FALSE, FALSE);
 150         if (socket == RPC_ANYSOCK) {
 151                 if (proto == IPPROTO_TCP && errno == ETIMEDOUT) {
 152                         /*
 153                          * TCP SYN timed out, so exit now.
 154                          */
 155                         rpc_createerr.cf_stat = RPC_TIMEDOUT;
 156                 }
 157                 return 0;
 158         }
 159
 160         switch (proto) {
 161         case IPPROTO_UDP:
 162                 clnt = clntudp_bufcreate(saddr,
 163                                          PMAPPROG, PMAPVERS,
 164                                          RETRY_TIMEOUT, &socket,
 165                                          RPCSMALLMSGSIZE,
 166                                          RPCSMALLMSGSIZE);
 167                 break;
 168         case IPPROTO_TCP:
 169                 clnt = clnttcp_create(saddr, PMAPPROG, PMAPVERS, &socket,
 170                                       RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
 171                 break;
 172         }
 173         if (clnt != NULL) {
 174                 struct pmap parms = {
 175                         .pm_prog        = program,
 176                         .pm_vers        = version,
 177                         .pm_prot        = proto,
 178                 };
 179
 180                 stat = clnt_call(clnt, PMAPPROC_GETPORT,
 181                                  (xdrproc_t)xdr_pmap, (caddr_t)&parms,
 182                                  (xdrproc_t)xdr_u_short, (caddr_t)&port,
 183                                  TIMEOUT);
 184                 if (stat) {
 185                         clnt_geterr(clnt, &rpc_createerr.cf_error);
 186                         rpc_createerr.cf_stat = stat;
 187                 }
 188                 clnt_destroy(clnt);
 189                 if (stat != RPC_SUCCESS)
 190                         port = 0;
 191                 else if (port == 0)
 192                         rpc_createerr.cf_stat = RPC_PROGNOTREGISTERED;
 193         }
 194         if (socket != 1)
 195                 close(socket);
 196
 197         return port;
 198 }
 199
 200 /*
 201  * Use the portmapper to discover whether or not the service we want is
 202  * available. The lists 'versions' and 'protos' define ordered sequences
 203  * of service versions and udp/tcp protocols to probe for.
 204  */
 205 static int probe_port(clnt_addr_t *server, const unsigned long *versions,
 206                         const unsigned int *protos)
 207 {
 208         struct sockaddr_in *saddr = &server->saddr;
 209         struct pmap *pmap = &server->pmap;
 210         const unsigned long prog = pmap->pm_prog, *p_vers;
 211         const unsigned int prot = (u_int)pmap->pm_prot, *p_prot;
 212         const u_short port = (u_short) pmap->pm_port;
 213         unsigned long vers = pmap->pm_vers;
 214         unsigned short p_port;
 215
 216         p_prot = prot ? &prot : protos;
 217         p_vers = vers ? &vers : versions;
 218         rpc_createerr.cf_stat = 0;
 219         for (;;) {
 220                 saddr->sin_port = htons(PMAPPORT);
 221                 p_port = getport(saddr, prog, *p_vers, *p_prot);
 222                 if (p_port) {
 223                         if (!port || port == p_port) {
 224                                 saddr->sin_port = htons(p_port);
 225                                 if (verbose) {
 226                                         printf(_("%s: trying %s prog %ld vers "
 227                                                 "%ld prot %s port %d\n"),
 228                                                 progname,
 229                                                 inet_ntoa(saddr->sin_addr),
 230                                                 prog, *p_vers,
 231                                                 *p_prot == IPPROTO_UDP ?
 232                                                         "udp" : "tcp",
 233                                                 p_port);
 234                                 }
 235                                 if (clnt_ping(saddr, prog, *p_vers, *p_prot, NULL))
 236                                         goto out_ok;
 237                                 if (rpc_createerr.cf_stat == RPC_TIMEDOUT)
 238                                         goto out_bad;
 239                         }
 240                 }
 241                 if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED)
 242                         goto out_bad;
 243
 244                 if (!prot) {
 245                         if (*++p_prot)
 246                                 continue;
 247                         p_prot = protos;
 248                 }
 249                 if (vers == pmap->pm_vers) {
 250                         p_vers = versions;
 251                         vers = 0;
 252                 }
 253                 if (vers || !*++p_vers)
 254                         break;
 255         }
 256
 257 out_bad:
 258         return 0;
 259
 260 out_ok:
 261         if (!vers)
 262                 pmap->pm_vers = *p_vers;
 263         if (!prot)
 264                 pmap->pm_prot = *p_prot;
 265         if (!port)
 266                 pmap->pm_port = p_port;
 267         rpc_createerr.cf_stat = 0;
 268         return 1;
 269 }
 270
 271 static int probe_nfsport(clnt_addr_t *nfs_server)
 272 {
 273         struct pmap *pmap = &nfs_server->pmap;
 274
 275         if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
 276                 return 1;
 277
 278         if (nfs_mount_data_version >= 4)
 279                 return probe_port(nfs_server, probe_nfs3_first, probe_tcp_first);
 280         else
 281                 return probe_port(nfs_server, probe_nfs2_only, probe_udp_only);
 282 }
 283
 284 static int probe_mntport(clnt_addr_t *mnt_server)
 285 {
 286         struct pmap *pmap = &mnt_server->pmap;
 287
 288         if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
 289                 return 1;
 290
 291         if (nfs_mount_data_version >= 4)
 292                 return probe_port(mnt_server, probe_mnt3_first, probe_udp_first);
 293         else
 294                 return probe_port(mnt_server, probe_mnt1_first, probe_udp_only);
 295 }
 296
 297 int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
 298 {
 299         struct pmap *nfs_pmap = &nfs_server->pmap;
 300         struct pmap *mnt_pmap = &mnt_server->pmap;
 301         struct pmap save_nfs, save_mnt;
 302         int res;
 303         const unsigned long *probe_vers;
 304
 305         if (mnt_pmap->pm_vers && !nfs_pmap->pm_vers)
 306                 nfs_pmap->pm_vers = mntvers_to_nfs(mnt_pmap->pm_vers);
 307         else if (nfs_pmap->pm_vers && !mnt_pmap->pm_vers)
 308                 mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
 309         if (nfs_pmap->pm_vers)
 310                 goto version_fixed;
 311
 312         memcpy(&save_nfs, nfs_pmap, sizeof(save_nfs));
 313         memcpy(&save_mnt, mnt_pmap, sizeof(save_mnt));
 314         probe_vers = (nfs_mount_data_version >= 4) ?
 315                         probe_mnt3_first : probe_mnt1_first;
 316
 317         for (; *probe_vers; probe_vers++) {
 318                 nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers);
 319                 if ((res = probe_nfsport(nfs_server) != 0)) {
 320                         mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
 321                         if ((res = probe_mntport(mnt_server)) != 0)
 322                                 return 1;
 323                         memcpy(mnt_pmap, &save_mnt, sizeof(*mnt_pmap));
 324                 }
 325                 switch (rpc_createerr.cf_stat) {
 326                 case RPC_PROGVERSMISMATCH:
 327                 case RPC_PROGNOTREGISTERED:
 328                         break;
 329                 default:
 330                         goto out_bad;
 331                 }
 332                 memcpy(nfs_pmap, &save_nfs, sizeof(*nfs_pmap));
 333         }
 334
 335 out_bad:
 336         return 0;
 337
 338 version_fixed:
 339         if (!probe_nfsport(nfs_server))
 340                 goto out_bad;
 341         return probe_mntport(mnt_server);
 342 }
 343
 344 static int probe_statd(void)
 345 {
 346         struct sockaddr_in addr;
 347         unsigned short port;
 348
 349         memset(&addr, 0, sizeof(addr));
 350         addr.sin_family = AF_INET;
 351         addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 352         port = getport(&addr, 100024, 1, IPPROTO_UDP);
 353
 354         if (port == 0)
 355                 return 0;
 356         addr.sin_port = htons(port);
 357
 358         if (clnt_ping(&addr, 100024, 1, IPPROTO_UDP, NULL) <= 0)
 359                 return 0;
 360
 361         return 1;
 362 }
 363
 364 /*
 365  * Attempt to start rpc.statd
 366  */
 367 int start_statd(void)
 368 {
 369 #ifdef START_STATD
 370         struct stat stb;
 371 #endif
 372
 373         if (probe_statd())
 374                 return 1;
 375
 376 #ifdef START_STATD
 377         if (stat(START_STATD, &stb) == 0) {
 378                 if (S_ISREG(stb.st_mode) && (stb.st_mode & S_IXUSR)) {
 379                         system(START_STATD);
 380                         if (probe_statd())
 381                                 return 1;
 382                 }
 383         }
 384 #endif
 385
 386         return 0;
 387 }
 388
 389 /*
 390  * nfs_call_umount - ask the server to remove a share from it's rmtab
 391  * @mnt_server: address of RPC MNT program server
 392  * @argp: directory path of share to "unmount"
 393  *
 394  * Returns one if the unmount call succeeded; zero if the unmount
 395  * failed for any reason.
 396  *
 397  * Note that a side effect of calling this function is that rpccreateerr
 398  * is set.
 399  */
 400 int nfs_call_umount(clnt_addr_t *mnt_server, dirpath *argp)
 401 {
 402         CLIENT *clnt;
 403         enum clnt_stat res = 0;
 404         int msock;
 405
 406         switch (mnt_server->pmap.pm_vers) {
 407         case 3:
 408         case 2:
 409         case 1:
 410                 if (!probe_mntport(mnt_server))
 411                         return 0;
 412                 clnt = mnt_openclnt(mnt_server, &msock);
 413                 if (!clnt)
 414                         return 0;
 415                 res = clnt_call(clnt, MOUNTPROC_UMNT,
 416                                 (xdrproc_t)xdr_dirpath, (caddr_t)argp,
 417                                 (xdrproc_t)xdr_void, NULL,
 418                                 TIMEOUT);
 419                 mnt_closeclnt(clnt, msock);
 420                 if (res == RPC_SUCCESS)
 421                         return 1;
 422                 break;
 423         default:
 424                 res = RPC_SUCCESS;
 425                 break;
 426         }
 427
 428         if (res == RPC_SUCCESS)
 429                 return 1;
 430         return 0;
 431 }
 432
 433 CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
 434 {
 435         struct sockaddr_in *mnt_saddr = &mnt_server->saddr;
 436         struct pmap *mnt_pmap = &mnt_server->pmap;
 437         CLIENT *clnt = NULL;
 438
 439         mnt_saddr->sin_port = htons((u_short)mnt_pmap->pm_port);
 440         *msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, TRUE, FALSE);
 441         if (*msock == RPC_ANYSOCK) {
 442                 if (rpc_createerr.cf_error.re_errno == EADDRINUSE)
 443                         /*
 444                          * Probably in-use by a TIME_WAIT connection,
 445                          * It is worth waiting a while and trying again.
 446                          */
 447                         rpc_createerr.cf_stat = RPC_TIMEDOUT;
 448                 return NULL;
 449         }
 450
 451         switch (mnt_pmap->pm_prot) {
 452         case IPPROTO_UDP:
 453                 clnt = clntudp_bufcreate(mnt_saddr,
 454                                          mnt_pmap->pm_prog, mnt_pmap->pm_vers,
 455                                          RETRY_TIMEOUT, msock,
 456                                          MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
 457                 break;
 458         case IPPROTO_TCP:
 459                 clnt = clnttcp_create(mnt_saddr,
 460                                       mnt_pmap->pm_prog, mnt_pmap->pm_vers,
 461                                       msock,
 462                                       MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
 463                 break;
 464         }
 465         if (clnt) {
 466                 /* try to mount hostname:dirname */
 467                 clnt->cl_auth = authunix_create_default();
 468                 return clnt;
 469         }
 470         return NULL;
 471 }
 472
 473 void mnt_closeclnt(CLIENT *clnt, int msock)
 474 {
 475         auth_destroy(clnt->cl_auth);
 476         clnt_destroy(clnt);
 477         close(msock);
 478 }