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