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