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, const char *nodename)
  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                 .nodename               = nodename,
  81                 .program                = &nsm_program,
  82                 .version                = NSM_VERSION,
  83                 .authflavor             = RPC_AUTH_NULL,
  84                 .flags                  = RPC_CLNT_CREATE_NOPING,
  85         };
  86
  87         return rpc_create(&args);
  88 }
  89
  90 static struct rpc_clnt *nsm_client_set(struct lockd_net *ln,
  91                 struct rpc_clnt *clnt)
  92 {
  93         spin_lock(&ln->nsm_clnt_lock);
  94         if (ln->nsm_users == 0) {
  95                 if (clnt == NULL)
  96                         goto out;
  97                 ln->nsm_clnt = clnt;
  98         }
  99         clnt = ln->nsm_clnt;
 100         ln->nsm_users++;
 101 out:
 102         spin_unlock(&ln->nsm_clnt_lock);
 103         return clnt;
 104 }
 105
 106 static struct rpc_clnt *nsm_client_get(struct net *net, const char *nodename)
 107 {
 108         struct rpc_clnt *clnt, *new;
 109         struct lockd_net *ln = net_generic(net, lockd_net_id);
 110
 111         clnt = nsm_client_set(ln, NULL);
 112         if (clnt != NULL)
 113                 goto out;
 114
 115         clnt = new = nsm_create(net, nodename);
 116         if (IS_ERR(clnt))
 117                 goto out;
 118
 119         clnt = nsm_client_set(ln, new);
 120         if (clnt != new)
 121                 rpc_shutdown_client(new);
 122 out:
 123         return clnt;
 124 }
 125
 126 static void nsm_client_put(struct net *net)
 127 {
 128         struct lockd_net *ln = net_generic(net, lockd_net_id);
 129         struct rpc_clnt *clnt = NULL;
 130
 131         spin_lock(&ln->nsm_clnt_lock);
 132         ln->nsm_users--;
 133         if (ln->nsm_users == 0) {
 134                 clnt = ln->nsm_clnt;
 135                 ln->nsm_clnt = NULL;
 136         }
 137         spin_unlock(&ln->nsm_clnt_lock);
 138         if (clnt != NULL)
 139                 rpc_shutdown_client(clnt);
 140 }
 141
 142 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res,
 143                          struct rpc_clnt *clnt)
 144 {
 145         int             status;
 146         struct nsm_args args = {
 147                 .priv           = &nsm->sm_priv,
 148                 .prog           = NLM_PROGRAM,
 149                 .vers           = 3,
 150                 .proc           = NLMPROC_NSM_NOTIFY,
 151                 .mon_name       = nsm->sm_mon_name,
 152                 .nodename       = clnt->cl_nodename,
 153         };
 154         struct rpc_message msg = {
 155                 .rpc_argp       = &args,
 156                 .rpc_resp       = res,
 157         };
 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 == -ECONNREFUSED) {
 164                 dprintk("lockd: NSM upcall RPC failed, status=%d, forcing rebind\n",
 165                                 status);
 166                 rpc_force_rebind(clnt);
 167                 status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
 168         }
 169         if (status < 0)
 170                 dprintk("lockd: NSM upcall RPC failed, status=%d\n",
 171                                 status);
 172         else
 173                 status = 0;
 174         return status;
 175 }
 176
 177 /**
 178  * nsm_monitor - Notify a peer in case we reboot
 179  * @host: pointer to nlm_host of peer to notify
 180  *
 181  * If this peer is not already monitored, this function sends an
 182  * upcall to the local rpc.statd to record the name/address of
 183  * the peer to notify in case we reboot.
 184  *
 185  * Returns zero if the peer is monitored by the local rpc.statd;
 186  * otherwise a negative errno value is returned.
 187  */
 188 int nsm_monitor(const struct nlm_host *host)
 189 {
 190         struct nsm_handle *nsm = host->h_nsmhandle;
 191         struct nsm_res  res;
 192         int             status;
 193         struct rpc_clnt *clnt;
 194         const char *nodename = NULL;
 195
 196         dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
 197
 198         if (nsm->sm_monitored)
 199                 return 0;
 200
 201         if (host->h_rpcclnt)
 202                 nodename = host->h_rpcclnt->cl_nodename;
 203
 204         /*
 205          * Choose whether to record the caller_name or IP address of
 206          * this peer in the local rpc.statd's database.
 207          */
 208         nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
 209
 210         clnt = nsm_client_get(host->net, nodename);
 211         if (IS_ERR(clnt)) {
 212                 status = PTR_ERR(clnt);
 213                 dprintk("lockd: failed to create NSM upcall transport, "
 214                                 "status=%d, net=%p\n", status, host->net);
 215                 return status;
 216         }
 217
 218         status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt);
 219         if (unlikely(res.status != 0))
 220                 status = -EIO;
 221         if (unlikely(status < 0)) {
 222                 pr_notice_ratelimited("lockd: cannot monitor %s\n", nsm->sm_name);
 223                 return status;
 224         }
 225
 226         nsm->sm_monitored = 1;
 227         if (unlikely(nsm_local_state != res.state)) {
 228                 nsm_local_state = res.state;
 229                 dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
 230         }
 231         return 0;
 232 }
 233
 234 /**
 235  * nsm_unmonitor - Unregister peer notification
 236  * @host: pointer to nlm_host of peer to stop monitoring
 237  *
 238  * If this peer is monitored, this function sends an upcall to
 239  * tell the local rpc.statd not to send this peer a notification
 240  * when we reboot.
 241  */
 242 void nsm_unmonitor(const struct nlm_host *host)
 243 {
 244         struct nsm_handle *nsm = host->h_nsmhandle;
 245         struct nsm_res  res;
 246         int status;
 247
 248         if (atomic_read(&nsm->sm_count) == 1
 249          && nsm->sm_monitored && !nsm->sm_sticky) {
 250                 struct lockd_net *ln = net_generic(host->net, lockd_net_id);
 251
 252                 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
 253
 254                 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt);
 255                 if (res.status != 0)
 256                         status = -EIO;
 257                 if (status < 0)
 258                         printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
 259                                         nsm->sm_name);
 260                 else
 261                         nsm->sm_monitored = 0;
 262
 263                 nsm_client_put(host->net);
 264         }
 265 }
 266
 267 static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
 268                                               const size_t len)
 269 {
 270         struct nsm_handle *nsm;
 271
 272         list_for_each_entry(nsm, &nsm_handles, sm_link)
 273                 if (strlen(nsm->sm_name) == len &&
 274                     memcmp(nsm->sm_name, hostname, len) == 0)
 275                         return nsm;
 276         return NULL;
 277 }
 278
 279 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
 280 {
 281         struct nsm_handle *nsm;
 282
 283         list_for_each_entry(nsm, &nsm_handles, sm_link)
 284                 if (rpc_cmp_addr(nsm_addr(nsm), sap))
 285                         return nsm;
 286         return NULL;
 287 }
 288
 289 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
 290 {
 291         struct nsm_handle *nsm;
 292
 293         list_for_each_entry(nsm, &nsm_handles, sm_link)
 294                 if (memcmp(nsm->sm_priv.data, priv->data,
 295                                         sizeof(priv->data)) == 0)
 296                         return nsm;
 297         return NULL;
 298 }
 299
 300 /*
 301  * Construct a unique cookie to match this nsm_handle to this monitored
 302  * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
 303  * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
 304  * requests.
 305  *
 306  * The NSM protocol requires that these cookies be unique while the
 307  * system is running.  We prefer a stronger requirement of making them
 308  * unique across reboots.  If user space bugs cause a stale cookie to
 309  * be sent to the kernel, it could cause the wrong host to lose its
 310  * lock state if cookies were not unique across reboots.
 311  *
 312  * The cookies are exposed only to local user space via loopback.  They
 313  * do not appear on the physical network.  If we want greater security
 314  * for some reason, nsm_init_private() could perform a one-way hash to
 315  * obscure the contents of the cookie.
 316  */
 317 static void nsm_init_private(struct nsm_handle *nsm)
 318 {
 319         u64 *p = (u64 *)&nsm->sm_priv.data;
 320         s64 ns;
 321
 322         ns = ktime_get_ns();
 323         put_unaligned(ns, p);
 324         put_unaligned((unsigned long)nsm, p + 1);
 325 }
 326
 327 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
 328                                             const size_t salen,
 329                                             const char *hostname,
 330                                             const size_t hostname_len)
 331 {
 332         struct nsm_handle *new;
 333
 334         new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
 335         if (unlikely(new == NULL))
 336                 return NULL;
 337
 338         atomic_set(&new->sm_count, 1);
 339         new->sm_name = (char *)(new + 1);
 340         memcpy(nsm_addr(new), sap, salen);
 341         new->sm_addrlen = salen;
 342         nsm_init_private(new);
 343
 344         if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
 345                                         sizeof(new->sm_addrbuf)) == 0)
 346                 (void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),
 347                                 "unsupported address family");
 348         memcpy(new->sm_name, hostname, hostname_len);
 349         new->sm_name[hostname_len] = '\0';
 350
 351         return new;
 352 }
 353
 354 /**
 355  * nsm_get_handle - Find or create a cached nsm_handle
 356  * @sap: pointer to socket address of handle to find
 357  * @salen: length of socket address
 358  * @hostname: pointer to C string containing hostname to find
 359  * @hostname_len: length of C string
 360  *
 361  * Behavior is modulated by the global nsm_use_hostnames variable.
 362  *
 363  * Returns a cached nsm_handle after bumping its ref count, or
 364  * returns a fresh nsm_handle if a handle that matches @sap and/or
 365  * @hostname cannot be found in the handle cache.  Returns NULL if
 366  * an error occurs.
 367  */
 368 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
 369                                   const size_t salen, const char *hostname,
 370                                   const size_t hostname_len)
 371 {
 372         struct nsm_handle *cached, *new = NULL;
 373
 374         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 375                 if (printk_ratelimit()) {
 376                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 377                                             "in NFS lock request\n",
 378                                 (int)hostname_len, hostname);
 379                 }
 380                 return NULL;
 381         }
 382
 383 retry:
 384         spin_lock(&nsm_lock);
 385
 386         if (nsm_use_hostnames && hostname != NULL)
 387                 cached = nsm_lookup_hostname(hostname, hostname_len);
 388         else
 389                 cached = nsm_lookup_addr(sap);
 390
 391         if (cached != NULL) {
 392                 atomic_inc(&cached->sm_count);
 393                 spin_unlock(&nsm_lock);
 394                 kfree(new);
 395                 dprintk("lockd: found nsm_handle for %s (%s), "
 396                                 "cnt %d\n", cached->sm_name,
 397                                 cached->sm_addrbuf,
 398                                 atomic_read(&cached->sm_count));
 399                 return cached;
 400         }
 401
 402         if (new != NULL) {
 403                 list_add(&new->sm_link, &nsm_handles);
 404                 spin_unlock(&nsm_lock);
 405                 dprintk("lockd: created nsm_handle for %s (%s)\n",
 406                                 new->sm_name, new->sm_addrbuf);
 407                 return new;
 408         }
 409
 410         spin_unlock(&nsm_lock);
 411
 412         new = nsm_create_handle(sap, salen, hostname, hostname_len);
 413         if (unlikely(new == NULL))
 414                 return NULL;
 415         goto retry;
 416 }
 417
 418 /**
 419  * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
 420  * @info: pointer to NLMPROC_SM_NOTIFY arguments
 421  *
 422  * Returns a matching nsm_handle if found in the nsm cache. The returned
 423  * nsm_handle's reference count is bumped. Otherwise returns NULL if some
 424  * error occurred.
 425  */
 426 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)
 427 {
 428         struct nsm_handle *cached;
 429
 430         spin_lock(&nsm_lock);
 431
 432         cached = nsm_lookup_priv(&info->priv);
 433         if (unlikely(cached == NULL)) {
 434                 spin_unlock(&nsm_lock);
 435                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 436                                 info->len, info->mon);
 437                 return cached;
 438         }
 439
 440         atomic_inc(&cached->sm_count);
 441         spin_unlock(&nsm_lock);
 442
 443         dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
 444                         cached->sm_name, cached->sm_addrbuf,
 445                         atomic_read(&cached->sm_count));
 446         return cached;
 447 }
 448
 449 /**
 450  * nsm_release - Release an NSM handle
 451  * @nsm: pointer to handle to be released
 452  *
 453  */
 454 void nsm_release(struct nsm_handle *nsm)
 455 {
 456         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 457                 list_del(&nsm->sm_link);
 458                 spin_unlock(&nsm_lock);
 459                 dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
 460                                 nsm->sm_name, nsm->sm_addrbuf);
 461                 kfree(nsm);
 462         }
 463 }
 464
 465 /*
 466  * XDR functions for NSM.
 467  *
 468  * See http://www.opengroup.org/ for details on the Network
 469  * Status Monitor wire protocol.
 470  */
 471
 472 static void encode_nsm_string(struct xdr_stream *xdr, const char *string)
 473 {
 474         const u32 len = strlen(string);
 475         __be32 *p;
 476
 477         p = xdr_reserve_space(xdr, 4 + len);
 478         xdr_encode_opaque(p, string, len);
 479 }
 480
 481 /*
 482  * "mon_name" specifies the host to be monitored.
 483  */
 484 static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
 485 {
 486         encode_nsm_string(xdr, argp->mon_name);
 487 }
 488
 489 /*
 490  * The "my_id" argument specifies the hostname and RPC procedure
 491  * to be called when the status manager receives notification
 492  * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
 493  * has changed.
 494  */
 495 static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 496 {
 497         __be32 *p;
 498
 499         encode_nsm_string(xdr, argp->nodename);
 500         p = xdr_reserve_space(xdr, 4 + 4 + 4);
 501         *p++ = cpu_to_be32(argp->prog);
 502         *p++ = cpu_to_be32(argp->vers);
 503         *p = cpu_to_be32(argp->proc);
 504 }
 505
 506 /*
 507  * The "mon_id" argument specifies the non-private arguments
 508  * of an NSMPROC_MON or NSMPROC_UNMON call.
 509  */
 510 static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 511 {
 512         encode_mon_name(xdr, argp);
 513         encode_my_id(xdr, argp);
 514 }
 515
 516 /*
 517  * The "priv" argument may contain private information required
 518  * by the NSMPROC_MON call. This information will be supplied in the
 519  * NLMPROC_SM_NOTIFY call.
 520  */
 521 static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
 522 {
 523         __be32 *p;
 524
 525         p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
 526         xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
 527 }
 528
 529 static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
 530                             const struct nsm_args *argp)
 531 {
 532         encode_mon_id(xdr, argp);
 533         encode_priv(xdr, argp);
 534 }
 535
 536 static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
 537                               const struct nsm_args *argp)
 538 {
 539         encode_mon_id(xdr, argp);
 540 }
 541
 542 static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,
 543                                 struct xdr_stream *xdr,
 544                                 struct nsm_res *resp)
 545 {
 546         __be32 *p;
 547
 548         p = xdr_inline_decode(xdr, 4 + 4);
 549         if (unlikely(p == NULL))
 550                 return -EIO;
 551         resp->status = be32_to_cpup(p++);
 552         resp->state = be32_to_cpup(p);
 553
 554         dprintk("lockd: %s status %d state %d\n",
 555                 __func__, resp->status, resp->state);
 556         return 0;
 557 }
 558
 559 static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp,
 560                             struct xdr_stream *xdr,
 561                             struct nsm_res *resp)
 562 {
 563         __be32 *p;
 564
 565         p = xdr_inline_decode(xdr, 4);
 566         if (unlikely(p == NULL))
 567                 return -EIO;
 568         resp->state = be32_to_cpup(p);
 569
 570         dprintk("lockd: %s state %d\n", __func__, resp->state);
 571         return 0;
 572 }
 573
 574 #define SM_my_name_sz   (1+XDR_QUADLEN(SM_MAXSTRLEN))
 575 #define SM_my_id_sz     (SM_my_name_sz+3)
 576 #define SM_mon_name_sz  (1+XDR_QUADLEN(SM_MAXSTRLEN))
 577 #define SM_mon_id_sz    (SM_mon_name_sz+SM_my_id_sz)
 578 #define SM_priv_sz      (XDR_QUADLEN(SM_PRIV_SIZE))
 579 #define SM_mon_sz       (SM_mon_id_sz+SM_priv_sz)
 580 #define SM_monres_sz    2
 581 #define SM_unmonres_sz  1
 582
 583 static struct rpc_procinfo      nsm_procedures[] = {
 584 [NSMPROC_MON] = {
 585                 .p_proc         = NSMPROC_MON,
 586                 .p_encode       = (kxdreproc_t)nsm_xdr_enc_mon,
 587                 .p_decode       = (kxdrdproc_t)nsm_xdr_dec_stat_res,
 588                 .p_arglen       = SM_mon_sz,
 589                 .p_replen       = SM_monres_sz,
 590                 .p_statidx      = NSMPROC_MON,
 591                 .p_name         = "MONITOR",
 592         },
 593 [NSMPROC_UNMON] = {
 594                 .p_proc         = NSMPROC_UNMON,
 595                 .p_encode       = (kxdreproc_t)nsm_xdr_enc_unmon,
 596                 .p_decode       = (kxdrdproc_t)nsm_xdr_dec_stat,
 597                 .p_arglen       = SM_mon_id_sz,
 598                 .p_replen       = SM_unmonres_sz,
 599                 .p_statidx      = NSMPROC_UNMON,
 600                 .p_name         = "UNMONITOR",
 601         },
 602 };
 603
 604 static const struct rpc_version nsm_version1 = {
 605                 .number         = 1,
 606                 .nrprocs        = ARRAY_SIZE(nsm_procedures),
 607                 .procs          = nsm_procedures
 608 };
 609
 610 static const struct rpc_version *nsm_version[] = {
 611         [1] = &nsm_version1,
 612 };
 613
 614 static struct rpc_stat          nsm_stats;
 615
 616 static const struct rpc_program nsm_program = {
 617                 .name           = "statd",
 618                 .number         = NSM_PROGRAM,
 619                 .nrvers         = ARRAY_SIZE(nsm_version),
 620                 .version        = nsm_version,
 621                 .stats          = &nsm_stats
 622 };