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 #if SIZEOF_SOCKLEN_T - 0 == 0
  57 #define socklen_t unsigned int
  58 #endif
  59
  60 extern int nfs_mount_data_version;
  61 extern char *progname;
  62 extern int verbose;
  63
  64 static const unsigned long nfs_to_mnt[] = {
  65         0,
  66         0,
  67         1,
  68         3,
  69 };
  70
  71 static const unsigned long mnt_to_nfs[] = {
  72         0,
  73         2,
  74         2,
  75         3,
  76 };
  77
  78 /*
  79  * Map an NFS version into the corresponding Mountd version
  80  */
  81 unsigned long nfsvers_to_mnt(const unsigned long vers)
  82 {
  83         if (vers <= 3)
  84                 return nfs_to_mnt[vers];
  85         return 0;
  86 }
  87
  88 /*
  89  * Map a Mountd version into the corresponding NFS version
  90  */
  91 static unsigned long mntvers_to_nfs(const unsigned long vers)
  92 {
  93         if (vers <= 3)
  94                 return mnt_to_nfs[vers];
  95         return 0;
  96 }
  97
  98 static const unsigned int probe_udp_only[] = {
  99         IPPROTO_UDP,
 100         0,
 101 };
 102
 103 static const unsigned int probe_udp_first[] = {
 104         IPPROTO_UDP,
 105         IPPROTO_TCP,
 106         0,
 107 };
 108
 109 static const unsigned int probe_tcp_first[] = {
 110         IPPROTO_TCP,
 111         IPPROTO_UDP,
 112         0,
 113 };
 114
 115 static const unsigned long probe_nfs2_only[] = {
 116         2,
 117         0,
 118 };
 119
 120 static const unsigned long probe_nfs3_first[] = {
 121         3,
 122         2,
 123         0,
 124 };
 125
 126 static const unsigned long probe_mnt1_first[] = {
 127         1,
 128         2,
 129         0,
 130 };
 131
 132 static const unsigned long probe_mnt3_first[] = {
 133         3,
 134         1,
 135         2,
 136         0,
 137 };
 138
 139 int nfs_gethostbyname(const char *hostname, struct sockaddr_in *saddr)
 140 {
 141         struct hostent *hp;
 142
 143         saddr->sin_family = AF_INET;
 144         if (!inet_aton(hostname, &saddr->sin_addr)) {
 145                 if ((hp = gethostbyname(hostname)) == NULL) {
 146                         nfs_error(_("%s: can't get address for %s\n"),
 147                                         progname, hostname);
 148                         return 0;
 149                 } else {
 150                         if (hp->h_length > sizeof(*saddr)) {
 151                                 nfs_error(_("%s: got bad hp->h_length\n"),
 152                                                 progname);
 153                                 hp->h_length = sizeof(*saddr);
 154                         }
 155                         memcpy(&saddr->sin_addr, hp->h_addr, hp->h_length);
 156                 }
 157         }
 158         return 1;
 159 }
 160
 161 /*
 162  * getport() is very similar to pmap_getport() with the exception that
 163  * this version tries to use an ephemeral port, since reserved ports are
 164  * not needed for GETPORT queries.  This conserves the very limited
 165  * reserved port space, which helps reduce failed socket binds
 166  * during mount storms.
 167  *
 168  * A side effect of calling this function is that rpccreateerr is set.
 169  */
 170 static unsigned short getport(struct sockaddr_in *saddr,
 171                                 unsigned long program,
 172                                 unsigned long version,
 173                                 unsigned int proto)
 174 {
 175         unsigned short port = 0;
 176         int socket;
 177         CLIENT *clnt = NULL;
 178         enum clnt_stat stat;
 179
 180         saddr->sin_port = htons(PMAPPORT);
 181
 182         /*
 183          * Try to get a socket with a non-privileged port.
 184          * clnt*create() will create one anyway if this
 185          * fails.
 186          */
 187         socket = get_socket(saddr, proto, FALSE, FALSE);
 188         if (socket == RPC_ANYSOCK) {
 189                 if (proto == IPPROTO_TCP && errno == ETIMEDOUT) {
 190                         /*
 191                          * TCP SYN timed out, so exit now.
 192                          */
 193                         rpc_createerr.cf_stat = RPC_TIMEDOUT;
 194                 }
 195                 return 0;
 196         }
 197
 198         switch (proto) {
 199         case IPPROTO_UDP:
 200                 clnt = clntudp_bufcreate(saddr,
 201                                          PMAPPROG, PMAPVERS,
 202                                          RETRY_TIMEOUT, &socket,
 203                                          RPCSMALLMSGSIZE,
 204                                          RPCSMALLMSGSIZE);
 205                 break;
 206         case IPPROTO_TCP:
 207                 clnt = clnttcp_create(saddr, PMAPPROG, PMAPVERS, &socket,
 208                                       RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
 209                 break;
 210         }
 211         if (clnt != NULL) {
 212                 struct pmap parms = {
 213                         .pm_prog        = program,
 214                         .pm_vers        = version,
 215                         .pm_prot        = proto,
 216                 };
 217
 218                 stat = clnt_call(clnt, PMAPPROC_GETPORT,
 219                                  (xdrproc_t)xdr_pmap, (caddr_t)&parms,
 220                                  (xdrproc_t)xdr_u_short, (caddr_t)&port,
 221                                  TIMEOUT);
 222                 if (stat) {
 223                         clnt_geterr(clnt, &rpc_createerr.cf_error);
 224                         rpc_createerr.cf_stat = stat;
 225                 }
 226                 clnt_destroy(clnt);
 227                 if (stat != RPC_SUCCESS)
 228                         port = 0;
 229                 else if (port == 0)
 230                         rpc_createerr.cf_stat = RPC_PROGNOTREGISTERED;
 231         }
 232         if (socket != 1)
 233                 close(socket);
 234
 235         return port;
 236 }
 237
 238 /*
 239  * Use the portmapper to discover whether or not the service we want is
 240  * available. The lists 'versions' and 'protos' define ordered sequences
 241  * of service versions and udp/tcp protocols to probe for.
 242  */
 243 static int probe_port(clnt_addr_t *server, const unsigned long *versions,
 244                         const unsigned int *protos)
 245 {
 246         struct sockaddr_in *saddr = &server->saddr;
 247         struct pmap *pmap = &server->pmap;
 248         const unsigned long prog = pmap->pm_prog, *p_vers;
 249         const unsigned int prot = (u_int)pmap->pm_prot, *p_prot;
 250         const u_short port = (u_short) pmap->pm_port;
 251         unsigned long vers = pmap->pm_vers;
 252         unsigned short p_port;
 253
 254         p_prot = prot ? &prot : protos;
 255         p_vers = vers ? &vers : versions;
 256         rpc_createerr.cf_stat = 0;
 257         for (;;) {
 258                 saddr->sin_port = htons(PMAPPORT);
 259                 p_port = getport(saddr, prog, *p_vers, *p_prot);
 260                 if (p_port) {
 261                         if (!port || port == p_port) {
 262                                 saddr->sin_port = htons(p_port);
 263                                 if (verbose) {
 264                                         printf(_("%s: trying %s prog %ld vers "
 265                                                 "%ld prot %s port %d\n"),
 266                                                 progname,
 267                                                 inet_ntoa(saddr->sin_addr),
 268                                                 prog, *p_vers,
 269                                                 *p_prot == IPPROTO_UDP ?
 270                                                         "udp" : "tcp",
 271                                                 p_port);
 272                                 }
 273                                 if (clnt_ping(saddr, prog, *p_vers, *p_prot, NULL))
 274                                         goto out_ok;
 275                                 if (rpc_createerr.cf_stat == RPC_TIMEDOUT)
 276                                         goto out_bad;
 277                         }
 278                 }
 279                 if (rpc_createerr.cf_stat != RPC_PROGNOTREGISTERED)
 280                         goto out_bad;
 281
 282                 if (!prot) {
 283                         if (*++p_prot)
 284                                 continue;
 285                         p_prot = protos;
 286                 }
 287                 if (vers == pmap->pm_vers) {
 288                         p_vers = versions;
 289                         vers = 0;
 290                 }
 291                 if (vers || !*++p_vers)
 292                         break;
 293         }
 294
 295 out_bad:
 296         return 0;
 297
 298 out_ok:
 299         if (!vers)
 300                 pmap->pm_vers = *p_vers;
 301         if (!prot)
 302                 pmap->pm_prot = *p_prot;
 303         if (!port)
 304                 pmap->pm_port = p_port;
 305         rpc_createerr.cf_stat = 0;
 306         return 1;
 307 }
 308
 309 static int probe_nfsport(clnt_addr_t *nfs_server)
 310 {
 311         struct pmap *pmap = &nfs_server->pmap;
 312
 313         if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
 314                 return 1;
 315
 316         if (nfs_mount_data_version >= 4)
 317                 return probe_port(nfs_server, probe_nfs3_first, probe_tcp_first);
 318         else
 319                 return probe_port(nfs_server, probe_nfs2_only, probe_udp_only);
 320 }
 321
 322 static int probe_mntport(clnt_addr_t *mnt_server)
 323 {
 324         struct pmap *pmap = &mnt_server->pmap;
 325
 326         if (pmap->pm_vers && pmap->pm_prot && pmap->pm_port)
 327                 return 1;
 328
 329         if (nfs_mount_data_version >= 4)
 330                 return probe_port(mnt_server, probe_mnt3_first, probe_udp_first);
 331         else
 332                 return probe_port(mnt_server, probe_mnt1_first, probe_udp_only);
 333 }
 334
 335 int probe_bothports(clnt_addr_t *mnt_server, clnt_addr_t *nfs_server)
 336 {
 337         struct pmap *nfs_pmap = &nfs_server->pmap;
 338         struct pmap *mnt_pmap = &mnt_server->pmap;
 339         struct pmap save_nfs, save_mnt;
 340         int res;
 341         const unsigned long *probe_vers;
 342
 343         if (mnt_pmap->pm_vers && !nfs_pmap->pm_vers)
 344                 nfs_pmap->pm_vers = mntvers_to_nfs(mnt_pmap->pm_vers);
 345         else if (nfs_pmap->pm_vers && !mnt_pmap->pm_vers)
 346                 mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
 347         if (nfs_pmap->pm_vers)
 348                 goto version_fixed;
 349
 350         memcpy(&save_nfs, nfs_pmap, sizeof(save_nfs));
 351         memcpy(&save_mnt, mnt_pmap, sizeof(save_mnt));
 352         probe_vers = (nfs_mount_data_version >= 4) ?
 353                         probe_mnt3_first : probe_mnt1_first;
 354
 355         for (; *probe_vers; probe_vers++) {
 356                 nfs_pmap->pm_vers = mntvers_to_nfs(*probe_vers);
 357                 if ((res = probe_nfsport(nfs_server) != 0)) {
 358                         mnt_pmap->pm_vers = nfsvers_to_mnt(nfs_pmap->pm_vers);
 359                         if ((res = probe_mntport(mnt_server)) != 0)
 360                                 return 1;
 361                         memcpy(mnt_pmap, &save_mnt, sizeof(*mnt_pmap));
 362                 }
 363                 switch (rpc_createerr.cf_stat) {
 364                 case RPC_PROGVERSMISMATCH:
 365                 case RPC_PROGNOTREGISTERED:
 366                         break;
 367                 default:
 368                         goto out_bad;
 369                 }
 370                 memcpy(nfs_pmap, &save_nfs, sizeof(*nfs_pmap));
 371         }
 372
 373 out_bad:
 374         return 0;
 375
 376 version_fixed:
 377         if (!probe_nfsport(nfs_server))
 378                 goto out_bad;
 379         return probe_mntport(mnt_server);
 380 }
 381
 382 static int probe_statd(void)
 383 {
 384         struct sockaddr_in addr;
 385         unsigned short port;
 386
 387         memset(&addr, 0, sizeof(addr));
 388         addr.sin_family = AF_INET;
 389         addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 390         port = getport(&addr, 100024, 1, IPPROTO_UDP);
 391
 392         if (port == 0)
 393                 return 0;
 394         addr.sin_port = htons(port);
 395
 396         if (clnt_ping(&addr, 100024, 1, IPPROTO_UDP, NULL) <= 0)
 397                 return 0;
 398
 399         return 1;
 400 }
 401
 402 /*
 403  * Attempt to start rpc.statd
 404  */
 405 int start_statd(void)
 406 {
 407 #ifdef START_STATD
 408         struct stat stb;
 409 #endif
 410
 411         if (probe_statd())
 412                 return 1;
 413
 414 #ifdef START_STATD
 415         if (stat(START_STATD, &stb) == 0) {
 416                 if (S_ISREG(stb.st_mode) && (stb.st_mode & S_IXUSR)) {
 417                         system(START_STATD);
 418                         if (probe_statd())
 419                                 return 1;
 420                 }
 421         }
 422 #endif
 423
 424         return 0;
 425 }
 426
 427 /*
 428  * nfs_call_umount - ask the server to remove a share from it's rmtab
 429  * @mnt_server: address of RPC MNT program server
 430  * @argp: directory path of share to "unmount"
 431  *
 432  * Returns one if the unmount call succeeded; zero if the unmount
 433  * failed for any reason.
 434  *
 435  * Note that a side effect of calling this function is that rpccreateerr
 436  * is set.
 437  */
 438 int nfs_call_umount(clnt_addr_t *mnt_server, dirpath *argp)
 439 {
 440         CLIENT *clnt;
 441         enum clnt_stat res = 0;
 442         int msock;
 443
 444         switch (mnt_server->pmap.pm_vers) {
 445         case 3:
 446         case 2:
 447         case 1:
 448                 if (!probe_mntport(mnt_server))
 449                         return 0;
 450                 clnt = mnt_openclnt(mnt_server, &msock);
 451                 if (!clnt)
 452                         return 0;
 453                 res = clnt_call(clnt, MOUNTPROC_UMNT,
 454                                 (xdrproc_t)xdr_dirpath, (caddr_t)argp,
 455                                 (xdrproc_t)xdr_void, NULL,
 456                                 TIMEOUT);
 457                 mnt_closeclnt(clnt, msock);
 458                 if (res == RPC_SUCCESS)
 459                         return 1;
 460                 break;
 461         default:
 462                 res = RPC_SUCCESS;
 463                 break;
 464         }
 465
 466         if (res == RPC_SUCCESS)
 467                 return 1;
 468         return 0;
 469 }
 470
 471 CLIENT *mnt_openclnt(clnt_addr_t *mnt_server, int *msock)
 472 {
 473         struct sockaddr_in *mnt_saddr = &mnt_server->saddr;
 474         struct pmap *mnt_pmap = &mnt_server->pmap;
 475         CLIENT *clnt = NULL;
 476
 477         mnt_saddr->sin_port = htons((u_short)mnt_pmap->pm_port);
 478         *msock = get_socket(mnt_saddr, mnt_pmap->pm_prot, TRUE, FALSE);
 479         if (*msock == RPC_ANYSOCK) {
 480                 if (rpc_createerr.cf_error.re_errno == EADDRINUSE)
 481                         /*
 482                          * Probably in-use by a TIME_WAIT connection,
 483                          * It is worth waiting a while and trying again.
 484                          */
 485                         rpc_createerr.cf_stat = RPC_TIMEDOUT;
 486                 return NULL;
 487         }
 488
 489         switch (mnt_pmap->pm_prot) {
 490         case IPPROTO_UDP:
 491                 clnt = clntudp_bufcreate(mnt_saddr,
 492                                          mnt_pmap->pm_prog, mnt_pmap->pm_vers,
 493                                          RETRY_TIMEOUT, msock,
 494                                          MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
 495                 break;
 496         case IPPROTO_TCP:
 497                 clnt = clnttcp_create(mnt_saddr,
 498                                       mnt_pmap->pm_prog, mnt_pmap->pm_vers,
 499                                       msock,
 500                                       MNT_SENDBUFSIZE, MNT_RECVBUFSIZE);
 501                 break;
 502         }
 503         if (clnt) {
 504                 /* try to mount hostname:dirname */
 505                 clnt->cl_auth = authunix_create_default();
 506                 return clnt;
 507         }
 508         return NULL;
 509 }
 510
 511 void mnt_closeclnt(CLIENT *clnt, int msock)
 512 {
 513         auth_destroy(clnt->cl_auth);
 514         clnt_destroy(clnt);
 515         close(msock);
 516 }
 517
 518 /*
 519  * Sigh... getport() doesn't actually check the version number.
 520  * In order to make sure that the server actually supports the service
 521  * we're requesting, we open and RPC client, and fire off a NULL
 522  * RPC call.
 523  */
 524 int clnt_ping(struct sockaddr_in *saddr, const unsigned long prog,
 525                 const unsigned long vers, const unsigned int prot,
 526                 struct sockaddr_in *caddr)
 527 {
 528         CLIENT *clnt = NULL;
 529         int sock, stat;
 530         static char clnt_res;
 531         struct sockaddr dissolve;
 532
 533         rpc_createerr.cf_stat = stat = errno = 0;
 534         sock = get_socket(saddr, prot, FALSE, TRUE);
 535         if (sock == RPC_ANYSOCK) {
 536                 if (errno == ETIMEDOUT) {
 537                         /*
 538                          * TCP timeout. Bubble up the error to see
 539                          * how it should be handled.
 540                          */
 541                         rpc_createerr.cf_stat = RPC_TIMEDOUT;
 542                 }
 543                 return 0;
 544         }
 545
 546         if (caddr) {
 547                 /* Get the address of our end of this connection */
 548                 socklen_t len = sizeof(*caddr);
 549                 if (getsockname(sock, caddr, &len) != 0)
 550                         caddr->sin_family = 0;
 551         }
 552
 553         switch(prot) {
 554         case IPPROTO_UDP:
 555                 /* The socket is connected (so we could getsockname successfully),
 556                  * but some servers on multi-homed hosts reply from
 557                  * the wrong address, so if we stay connected, we lose the reply.
 558                  */
 559                 dissolve.sa_family = AF_UNSPEC;
 560                 connect(sock, &dissolve, sizeof(dissolve));
 561
 562                 clnt = clntudp_bufcreate(saddr, prog, vers,
 563                                          RETRY_TIMEOUT, &sock,
 564                                          RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
 565                 break;
 566         case IPPROTO_TCP:
 567                 clnt = clnttcp_create(saddr, prog, vers, &sock,
 568                                       RPCSMALLMSGSIZE, RPCSMALLMSGSIZE);
 569                 break;
 570         }
 571         if (!clnt) {
 572                 close(sock);
 573                 return 0;
 574         }
 575         memset(&clnt_res, 0, sizeof(clnt_res));
 576         stat = clnt_call(clnt, NULLPROC,
 577                          (xdrproc_t)xdr_void, (caddr_t)NULL,
 578                          (xdrproc_t)xdr_void, (caddr_t)&clnt_res,
 579                          TIMEOUT);
 580         if (stat) {
 581                 clnt_geterr(clnt, &rpc_createerr.cf_error);
 582                 rpc_createerr.cf_stat = stat;
 583         }
 584         clnt_destroy(clnt);
 585         close(sock);
 586
 587         if (stat == RPC_SUCCESS)
 588                 return 1;
 589         else
 590                 return 0;
 591 }