fs/lockd/mon.c

   1 /*
   2  * linux/fs/lockd/mon.c
   3  *
   4  * The kernel statd client.
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/kernel.h>
  11 #include <linux/ktime.h>
  12 #include <linux/slab.h>
  13
  14 #include <linux/sunrpc/clnt.h>
  15 #include <linux/sunrpc/addr.h>
  16 #include <linux/sunrpc/xprtsock.h>
  17 #include <linux/sunrpc/svc.h>
  18 #include <linux/lockd/lockd.h>
  19
  20 #include <asm/unaligned.h>
  21
  22 #include "netns.h"
  23
  24 #define NLMDBG_FACILITY         NLMDBG_MONITOR
  25 #define NSM_PROGRAM             100024
  26 #define NSM_VERSION             1
  27
  28 enum {
  29         NSMPROC_NULL,
  30         NSMPROC_STAT,
  31         NSMPROC_MON,
  32         NSMPROC_UNMON,
  33         NSMPROC_UNMON_ALL,
  34         NSMPROC_SIMU_CRASH,
  35         NSMPROC_NOTIFY,
  36 };
  37
  38 struct nsm_args {
  39         struct nsm_private      *priv;
  40         u32                     prog;           /* RPC callback info */
  41         u32                     vers;
  42         u32                     proc;
  43
  44         char                    *mon_name;
  45         char                    *nodename;
  46 };
  47
  48 struct nsm_res {
  49         u32                     status;
  50         u32                     state;
  51 };
  52
  53 static const struct rpc_program nsm_program;
  54 static                          LIST_HEAD(nsm_handles);
  55 static                          DEFINE_SPINLOCK(nsm_lock);
  56
  57 /*
  58  * Local NSM state
  59  */
  60 u32     __read_mostly           nsm_local_state;
  61 bool    __read_mostly           nsm_use_hostnames;
  62
  63 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
  64 {
  65         return (struct sockaddr *)&nsm->sm_addr;
  66 }
  67
  68 static struct rpc_clnt *nsm_create(struct net *net)
  69 {
  70         struct sockaddr_in sin = {
  71                 .sin_family             = AF_INET,
  72                 .sin_addr.s_addr        = htonl(INADDR_LOOPBACK),
  73         };
  74         struct rpc_create_args args = {
  75                 .net                    = net,
  76                 .protocol               = XPRT_TRANSPORT_TCP,
  77                 .address                = (struct sockaddr *)&sin,
  78                 .addrsize               = sizeof(sin),
  79                 .servername             = "rpc.statd",
  80                 .program                = &nsm_program,
  81                 .version                = NSM_VERSION,
  82                 .authflavor             = RPC_AUTH_NULL,
  83                 .flags                  = RPC_CLNT_CREATE_NOPING,
  84         };
  85
  86         return rpc_create(&args);
  87 }
  88
  89 static struct rpc_clnt *nsm_client_set(struct lockd_net *ln,
  90                 struct rpc_clnt *clnt)
  91 {
  92         spin_lock(&ln->nsm_clnt_lock);
  93         if (ln->nsm_users == 0) {
  94                 if (clnt == NULL)
  95                         goto out;
  96                 ln->nsm_clnt = clnt;
  97         }
  98         clnt = ln->nsm_clnt;
  99         ln->nsm_users++;
 100 out:
 101         spin_unlock(&ln->nsm_clnt_lock);
 102         return clnt;
 103 }
 104
 105 static struct rpc_clnt *nsm_client_get(struct net *net)
 106 {
 107         struct rpc_clnt *clnt, *new;
 108         struct lockd_net *ln = net_generic(net, lockd_net_id);
 109
 110         clnt = nsm_client_set(ln, NULL);
 111         if (clnt != NULL)
 112                 goto out;
 113
 114         clnt = new = nsm_create(net);
 115         if (IS_ERR(clnt))
 116                 goto out;
 117
 118         clnt = nsm_client_set(ln, new);
 119         if (clnt != new)
 120                 rpc_shutdown_client(new);
 121 out:
 122         return clnt;
 123 }
 124
 125 static void nsm_client_put(struct net *net)
 126 {
 127         struct lockd_net *ln = net_generic(net, lockd_net_id);
 128         struct rpc_clnt *clnt = NULL;
 129
 130         spin_lock(&ln->nsm_clnt_lock);
 131         ln->nsm_users--;
 132         if (ln->nsm_users == 0) {
 133                 clnt = ln->nsm_clnt;
 134                 ln->nsm_clnt = NULL;
 135         }
 136         spin_unlock(&ln->nsm_clnt_lock);
 137         if (clnt != NULL)
 138                 rpc_shutdown_client(clnt);
 139 }
 140
 141 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res,
 142                          struct rpc_clnt *clnt)
 143 {
 144         int             status;
 145         struct nsm_args args = {
 146                 .priv           = &nsm->sm_priv,
 147                 .prog           = NLM_PROGRAM,
 148                 .vers           = 3,
 149                 .proc           = NLMPROC_NSM_NOTIFY,
 150                 .mon_name       = nsm->sm_mon_name,
 151                 .nodename       = clnt->cl_nodename,
 152         };
 153         struct rpc_message msg = {
 154                 .rpc_argp       = &args,
 155                 .rpc_resp       = res,
 156         };
 157
 158         memset(res, 0, sizeof(*res));
 159
 160         msg.rpc_proc = &clnt->cl_procinfo[proc];
 161         status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
 162         if (status == -ECONNREFUSED) {
 163                 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n",
 164                                 status);
 165                 rpc_force_rebind(clnt);
 166                 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
 167         }
 168         if (status < 0)
 169                 dprintk("lockd: NSM upcall RPC failed, status=%d\n",
 170                                 status);
 171         else
 172                 status = 0;
 173         return status;
 174 }
 175
 176 /**
 177  * nsm_monitor - Notify a peer in case we reboot
 178  * @host: pointer to nlm_host of peer to notify
 179  *
 180  * If this peer is not already monitored, this function sends an
 181  * upcall to the local rpc.statd to record the name/address of
 182  * the peer to notify in case we reboot.
 183  *
 184  * Returns zero if the peer is monitored by the local rpc.statd;
 185  * otherwise a negative errno value is returned.
 186  */
 187 int nsm_monitor(const struct nlm_host *host)
 188 {
 189         struct nsm_handle *nsm = host->h_nsmhandle;
 190         struct nsm_res  res;
 191         int             status;
 192         struct rpc_clnt *clnt;
 193
 194         dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
 195
 196         if (nsm->sm_monitored)
 197                 return 0;
 198
 199         /*
 200          * Choose whether to record the caller_name or IP address of
 201          * this peer in the local rpc.statd's database.
 202          */
 203         nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
 204
 205         clnt = nsm_client_get(host->net);
 206         if (IS_ERR(clnt)) {
 207                 status = PTR_ERR(clnt);
 208                 dprintk("lockd: failed to create NSM upcall transport, "
 209                                 "status=%d, net=%p\n", status, host->net);
 210                 return status;
 211         }
 212
 213         status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt);
 214         if (unlikely(res.status != 0))
 215                 status = -EIO;
 216         if (unlikely(status < 0)) {
 217                 printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name);
 218                 return status;
 219         }
 220
 221         nsm->sm_monitored = 1;
 222         if (unlikely(nsm_local_state != res.state)) {
 223                 nsm_local_state = res.state;
 224                 dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
 225         }
 226         return 0;
 227 }
 228
 229 /**
 230  * nsm_unmonitor - Unregister peer notification
 231  * @host: pointer to nlm_host of peer to stop monitoring
 232  *
 233  * If this peer is monitored, this function sends an upcall to
 234  * tell the local rpc.statd not to send this peer a notification
 235  * when we reboot.
 236  */
 237 void nsm_unmonitor(const struct nlm_host *host)
 238 {
 239         struct nsm_handle *nsm = host->h_nsmhandle;
 240         struct nsm_res  res;
 241         int status;
 242
 243         if (atomic_read(&nsm->sm_count) == 1
 244          && nsm->sm_monitored && !nsm->sm_sticky) {
 245                 struct lockd_net *ln = net_generic(host->net, lockd_net_id);
 246
 247                 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
 248
 249                 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt);
 250                 if (res.status != 0)
 251                         status = -EIO;
 252                 if (status < 0)
 253                         printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
 254                                         nsm->sm_name);
 255                 else
 256                         nsm->sm_monitored = 0;
 257
 258                 nsm_client_put(host->net);
 259         }
 260 }
 261
 262 static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
 263                                               const size_t len)
 264 {
 265         struct nsm_handle *nsm;
 266
 267         list_for_each_entry(nsm, &nsm_handles, sm_link)
 268                 if (strlen(nsm->sm_name) == len &&
 269                     memcmp(nsm->sm_name, hostname, len) == 0)
 270                         return nsm;
 271         return NULL;
 272 }
 273
 274 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
 275 {
 276         struct nsm_handle *nsm;
 277
 278         list_for_each_entry(nsm, &nsm_handles, sm_link)
 279                 if (rpc_cmp_addr(nsm_addr(nsm), sap))
 280                         return nsm;
 281         return NULL;
 282 }
 283
 284 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
 285 {
 286         struct nsm_handle *nsm;
 287
 288         list_for_each_entry(nsm, &nsm_handles, sm_link)
 289                 if (memcmp(nsm->sm_priv.data, priv->data,
 290                                         sizeof(priv->data)) == 0)
 291                         return nsm;
 292         return NULL;
 293 }
 294
 295 /*
 296  * Construct a unique cookie to match this nsm_handle to this monitored
 297  * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
 298  * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
 299  * requests.
 300  *
 301  * The NSM protocol requires that these cookies be unique while the
 302  * system is running.  We prefer a stronger requirement of making them
 303  * unique across reboots.  If user space bugs cause a stale cookie to
 304  * be sent to the kernel, it could cause the wrong host to lose its
 305  * lock state if cookies were not unique across reboots.
 306  *
 307  * The cookies are exposed only to local user space via loopback.  They
 308  * do not appear on the physical network.  If we want greater security
 309  * for some reason, nsm_init_private() could perform a one-way hash to
 310  * obscure the contents of the cookie.
 311  */
 312 static void nsm_init_private(struct nsm_handle *nsm)
 313 {
 314         u64 *p = (u64 *)&nsm->sm_priv.data;
 315         s64 ns;
 316
 317         ns = ktime_get_ns();
 318         put_unaligned(ns, p);
 319         put_unaligned((unsigned long)nsm, p + 1);
 320 }
 321
 322 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
 323                                             const size_t salen,
 324                                             const char *hostname,
 325                                             const size_t hostname_len)
 326 {
 327         struct nsm_handle *new;
 328
 329         new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
 330         if (unlikely(new == NULL))
 331                 return NULL;
 332
 333         atomic_set(&new->sm_count, 1);
 334         new->sm_name = (char *)(new + 1);
 335         memcpy(nsm_addr(new), sap, salen);
 336         new->sm_addrlen = salen;
 337         nsm_init_private(new);
 338
 339         if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
 340                                         sizeof(new->sm_addrbuf)) == 0)
 341                 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),
 342                                 "unsupported address family");
 343         memcpy(new->sm_name, hostname, hostname_len);
 344         new->sm_name[hostname_len] = '\0';
 345
 346         return new;
 347 }
 348
 349 /**
 350  * nsm_get_handle - Find or create a cached nsm_handle
 351  * @sap: pointer to socket address of handle to find
 352  * @salen: length of socket address
 353  * @hostname: pointer to C string containing hostname to find
 354  * @hostname_len: length of C string
 355  *
 356  * Behavior is modulated by the global nsm_use_hostnames variable.
 357  *
 358  * Returns a cached nsm_handle after bumping its ref count, or
 359  * returns a fresh nsm_handle if a handle that matches @sap and/or
 360  * @hostname cannot be found in the handle cache.  Returns NULL if
 361  * an error occurs.
 362  */
 363 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
 364                                   const size_t salen, const char *hostname,
 365                                   const size_t hostname_len)
 366 {
 367         struct nsm_handle *cached, *new = NULL;
 368
 369         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 370                 if (printk_ratelimit()) {
 371                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 372                                             "in NFS lock request\n",
 373                                 (int)hostname_len, hostname);
 374                 }
 375                 return NULL;
 376         }
 377
 378 retry:
 379         spin_lock(&nsm_lock);
 380
 381         if (nsm_use_hostnames && hostname != NULL)
 382                 cached = nsm_lookup_hostname(hostname, hostname_len);
 383         else
 384                 cached = nsm_lookup_addr(sap);
 385
 386         if (cached != NULL) {
 387                 atomic_inc(&cached->sm_count);
 388                 spin_unlock(&nsm_lock);
 389                 kfree(new);
 390                 dprintk("lockd: found nsm_handle for %s (%s), "
 391                                 "cnt %d\n", cached->sm_name,
 392                                 cached->sm_addrbuf,
 393                                 atomic_read(&cached->sm_count));
 394                 return cached;
 395         }
 396
 397         if (new != NULL) {
 398                 list_add(&new->sm_link, &nsm_handles);
 399                 spin_unlock(&nsm_lock);
 400                 dprintk("lockd: created nsm_handle for %s (%s)\n",
 401                                 new->sm_name, new->sm_addrbuf);
 402                 return new;
 403         }
 404
 405         spin_unlock(&nsm_lock);
 406
 407         new = nsm_create_handle(sap, salen, hostname, hostname_len);
 408         if (unlikely(new == NULL))
 409                 return NULL;
 410         goto retry;
 411 }
 412
 413 /**
 414  * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
 415  * @info: pointer to NLMPROC_SM_NOTIFY arguments
 416  *
 417  * Returns a matching nsm_handle if found in the nsm cache. The returned
 418  * nsm_handle's reference count is bumped. Otherwise returns NULL if some
 419  * error occurred.
 420  */
 421 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)
 422 {
 423         struct nsm_handle *cached;
 424
 425         spin_lock(&nsm_lock);
 426
 427         cached = nsm_lookup_priv(&info->priv);
 428         if (unlikely(cached == NULL)) {
 429                 spin_unlock(&nsm_lock);
 430                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 431                                 info->len, info->mon);
 432                 return cached;
 433         }
 434
 435         atomic_inc(&cached->sm_count);
 436         spin_unlock(&nsm_lock);
 437
 438         dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
 439                         cached->sm_name, cached->sm_addrbuf,
 440                         atomic_read(&cached->sm_count));
 441         return cached;
 442 }
 443
 444 /**
 445  * nsm_release - Release an NSM handle
 446  * @nsm: pointer to handle to be released
 447  *
 448  */
 449 void nsm_release(struct nsm_handle *nsm)
 450 {
 451         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 452                 list_del(&nsm->sm_link);
 453                 spin_unlock(&nsm_lock);
 454                 dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
 455                                 nsm->sm_name, nsm->sm_addrbuf);
 456                 kfree(nsm);
 457         }
 458 }
 459
 460 /*
 461  * XDR functions for NSM.
 462  *
 463  * See http://www.opengroup.org/ for details on the Network
 464  * Status Monitor wire protocol.
 465  */
 466
 467 static void encode_nsm_string(struct xdr_stream *xdr, const char *string)
 468 {
 469         const u32 len = strlen(string);
 470         __be32 *p;
 471
 472         p = xdr_reserve_space(xdr, 4 + len);
 473         xdr_encode_opaque(p, string, len);
 474 }
 475
 476 /*
 477  * "mon_name" specifies the host to be monitored.
 478  */
 479 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
 480 {
 481         encode_nsm_string(xdr, argp->mon_name);
 482 }
 483
 484 /*
 485  * The "my_id" argument specifies the hostname and RPC procedure
 486  * to be called when the status manager receives notification
 487  * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
 488  * has changed.
 489  */
 490 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 491 {
 492         __be32 *p;
 493
 494         encode_nsm_string(xdr, argp->nodename);
 495         p = xdr_reserve_space(xdr, 4 + 4 + 4);
 496         *p++ = cpu_to_be32(argp->prog);
 497         *p++ = cpu_to_be32(argp->vers);
 498         *p = cpu_to_be32(argp->proc);
 499 }
 500
 501 /*
 502  * The "mon_id" argument specifies the non-private arguments
 503  * of an NSMPROC_MON or NSMPROC_UNMON call.
 504  */
 505 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 506 {
 507         encode_mon_name(xdr, argp);
 508         encode_my_id(xdr, argp);
 509 }
 510
 511 /*
 512  * The "priv" argument may contain private information required
 513  * by the NSMPROC_MON call. This information will be supplied in the
 514  * NLMPROC_SM_NOTIFY call.
 515  */
 516 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
 517 {
 518         __be32 *p;
 519
 520         p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
 521         xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
 522 }
 523
 524 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
 525                             const struct nsm_args *argp)
 526 {
 527         encode_mon_id(xdr, argp);
 528         encode_priv(xdr, argp);
 529 }
 530
 531 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
 532                               const struct nsm_args *argp)
 533 {
 534         encode_mon_id(xdr, argp);
 535 }
 536
 537 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,
 538                                 struct xdr_stream *xdr,
 539                                 struct nsm_res *resp)
 540 {
 541         __be32 *p;
 542
 543         p = xdr_inline_decode(xdr, 4 + 4);
 544         if (unlikely(p == NULL))
 545                 return -EIO;
 546         resp->status = be32_to_cpup(p++);
 547         resp->state = be32_to_cpup(p);
 548
 549         dprintk("lockd: %s status %d state %d\n",
 550                 __func__, resp->status, resp->state);
 551         return 0;
 552 }
 553
 554 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp,
 555                             struct xdr_stream *xdr,
 556                             struct nsm_res *resp)
 557 {
 558         __be32 *p;
 559
 560         p = xdr_inline_decode(xdr, 4);
 561         if (unlikely(p == NULL))
 562                 return -EIO;
 563         resp->state = be32_to_cpup(p);
 564
 565         dprintk("lockd: %s state %d\n", __func__, resp->state);
 566         return 0;
 567 }
 568
 569 #define SM_my_name_sz   (1+XDR_QUADLEN(SM_MAXSTRLEN))
 570 #define SM_my_id_sz     (SM_my_name_sz+3)
 571 #define SM_mon_name_sz  (1+XDR_QUADLEN(SM_MAXSTRLEN))
 572 #define SM_mon_id_sz    (SM_mon_name_sz+SM_my_id_sz)
 573 #define SM_priv_sz      (XDR_QUADLEN(SM_PRIV_SIZE))
 574 #define SM_mon_sz       (SM_mon_id_sz+SM_priv_sz)
 575 #define SM_monres_sz    2
 576 #define SM_unmonres_sz  1
 577
 578 static struct rpc_procinfo      nsm_procedures[] = {
 579 [NSMPROC_MON] = {
 580                 .p_proc         = NSMPROC_MON,
 581                 .p_encode       = (kxdreproc_t)nsm_xdr_enc_mon,
 582                 .p_decode       = (kxdrdproc_t)nsm_xdr_dec_stat_res,
 583                 .p_arglen       = SM_mon_sz,
 584                 .p_replen       = SM_monres_sz,
 585                 .p_statidx      = NSMPROC_MON,
 586                 .p_name         = "MONITOR",
 587         },
 588 [NSMPROC_UNMON] = {
 589                 .p_proc         = NSMPROC_UNMON,
 590                 .p_encode       = (kxdreproc_t)nsm_xdr_enc_unmon,
 591                 .p_decode       = (kxdrdproc_t)nsm_xdr_dec_stat,
 592                 .p_arglen       = SM_mon_id_sz,
 593                 .p_replen       = SM_unmonres_sz,
 594                 .p_statidx      = NSMPROC_UNMON,
 595                 .p_name         = "UNMONITOR",
 596         },
 597 };
 598
 599 static const struct rpc_version nsm_version1 = {
 600                 .number         = 1,
 601                 .nrprocs        = ARRAY_SIZE(nsm_procedures),
 602                 .procs          = nsm_procedures
 603 };
 604
 605 static const struct rpc_version *nsm_version[] = {
 606         [1] = &nsm_version1,
 607 };
 608
 609 static struct rpc_stat          nsm_stats;
 610
 611 static const struct rpc_program nsm_program = {
 612                 .name           = "statd",
 613                 .number         = NSM_PROGRAM,
 614                 .nrvers         = ARRAY_SIZE(nsm_version),
 615                 .version        = nsm_version,
 616                 .stats          = &nsm_stats
 617 };