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/utsname.h>
  11 #include <linux/kernel.h>
  12 #include <linux/ktime.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 #define NLMDBG_FACILITY         NLMDBG_MONITOR
  22 #define NSM_PROGRAM             100024
  23 #define NSM_VERSION             1
  24
  25 enum {
  26         NSMPROC_NULL,
  27         NSMPROC_STAT,
  28         NSMPROC_MON,
  29         NSMPROC_UNMON,
  30         NSMPROC_UNMON_ALL,
  31         NSMPROC_SIMU_CRASH,
  32         NSMPROC_NOTIFY,
  33 };
  34
  35 struct nsm_args {
  36         struct nsm_private      *priv;
  37         u32                     prog;           /* RPC callback info */
  38         u32                     vers;
  39         u32                     proc;
  40
  41         char                    *mon_name;
  42 };
  43
  44 struct nsm_res {
  45         u32                     status;
  46         u32                     state;
  47 };
  48
  49 static struct rpc_program       nsm_program;
  50 static                          LIST_HEAD(nsm_handles);
  51 static                          DEFINE_SPINLOCK(nsm_lock);
  52
  53 /*
  54  * Local NSM state
  55  */
  56 u32     __read_mostly           nsm_local_state;
  57 int     __read_mostly           nsm_use_hostnames;
  58
  59 static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
  60 {
  61         return (struct sockaddr *)&nsm->sm_addr;
  62 }
  63
  64 static void nsm_display_ipv4_address(const struct sockaddr *sap, char *buf,
  65                                      const size_t len)
  66 {
  67         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  68         snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr);
  69 }
  70
  71 static void nsm_display_ipv6_address(const struct sockaddr *sap, char *buf,
  72                                      const size_t len)
  73 {
  74         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  75
  76         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
  77                 snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]);
  78         else if (sin6->sin6_scope_id != 0)
  79                 snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr,
  80                                 sin6->sin6_scope_id);
  81         else
  82                 snprintf(buf, len, "%pI6", &sin6->sin6_addr);
  83 }
  84
  85 static void nsm_display_address(const struct sockaddr *sap,
  86                                 char *buf, const size_t len)
  87 {
  88         switch (sap->sa_family) {
  89         case AF_INET:
  90                 nsm_display_ipv4_address(sap, buf, len);
  91                 break;
  92         case AF_INET6:
  93                 nsm_display_ipv6_address(sap, buf, len);
  94                 break;
  95         default:
  96                 snprintf(buf, len, "unsupported address family");
  97                 break;
  98         }
  99 }
 100
 101 static struct rpc_clnt *nsm_create(void)
 102 {
 103         struct sockaddr_in sin = {
 104                 .sin_family             = AF_INET,
 105                 .sin_addr.s_addr        = htonl(INADDR_LOOPBACK),
 106         };
 107         struct rpc_create_args args = {
 108                 .protocol               = XPRT_TRANSPORT_UDP,
 109                 .address                = (struct sockaddr *)&sin,
 110                 .addrsize               = sizeof(sin),
 111                 .servername             = "rpc.statd",
 112                 .program                = &nsm_program,
 113                 .version                = NSM_VERSION,
 114                 .authflavor             = RPC_AUTH_NULL,
 115                 .flags                  = RPC_CLNT_CREATE_NOPING,
 116         };
 117
 118         return rpc_create(&args);
 119 }
 120
 121 static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res)
 122 {
 123         struct rpc_clnt *clnt;
 124         int             status;
 125         struct nsm_args args = {
 126                 .priv           = &nsm->sm_priv,
 127                 .prog           = NLM_PROGRAM,
 128                 .vers           = 3,
 129                 .proc           = NLMPROC_NSM_NOTIFY,
 130                 .mon_name       = nsm->sm_mon_name,
 131         };
 132         struct rpc_message msg = {
 133                 .rpc_argp       = &args,
 134                 .rpc_resp       = res,
 135         };
 136
 137         clnt = nsm_create();
 138         if (IS_ERR(clnt)) {
 139                 status = PTR_ERR(clnt);
 140                 dprintk("lockd: failed to create NSM upcall transport, "
 141                                 "status=%d\n", status);
 142                 goto out;
 143         }
 144
 145         memset(res, 0, sizeof(*res));
 146
 147         msg.rpc_proc = &clnt->cl_procinfo[proc];
 148         status = rpc_call_sync(clnt, &msg, 0);
 149         if (status < 0)
 150                 dprintk("lockd: NSM upcall RPC failed, status=%d\n",
 151                                 status);
 152         else
 153                 status = 0;
 154         rpc_shutdown_client(clnt);
 155  out:
 156         return status;
 157 }
 158
 159 /**
 160  * nsm_monitor - Notify a peer in case we reboot
 161  * @host: pointer to nlm_host of peer to notify
 162  *
 163  * If this peer is not already monitored, this function sends an
 164  * upcall to the local rpc.statd to record the name/address of
 165  * the peer to notify in case we reboot.
 166  *
 167  * Returns zero if the peer is monitored by the local rpc.statd;
 168  * otherwise a negative errno value is returned.
 169  */
 170 int nsm_monitor(const struct nlm_host *host)
 171 {
 172         struct nsm_handle *nsm = host->h_nsmhandle;
 173         struct nsm_res  res;
 174         int             status;
 175
 176         dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
 177
 178         if (nsm->sm_monitored)
 179                 return 0;
 180
 181         /*
 182          * Choose whether to record the caller_name or IP address of
 183          * this peer in the local rpc.statd's database.
 184          */
 185         nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
 186
 187         status = nsm_mon_unmon(nsm, NSMPROC_MON, &res);
 188         if (unlikely(res.status != 0))
 189                 status = -EIO;
 190         if (unlikely(status < 0)) {
 191                 printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name);
 192                 return status;
 193         }
 194
 195         nsm->sm_monitored = 1;
 196         if (unlikely(nsm_local_state != res.state)) {
 197                 nsm_local_state = res.state;
 198                 dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
 199         }
 200         return 0;
 201 }
 202
 203 /**
 204  * nsm_unmonitor - Unregister peer notification
 205  * @host: pointer to nlm_host of peer to stop monitoring
 206  *
 207  * If this peer is monitored, this function sends an upcall to
 208  * tell the local rpc.statd not to send this peer a notification
 209  * when we reboot.
 210  */
 211 void nsm_unmonitor(const struct nlm_host *host)
 212 {
 213         struct nsm_handle *nsm = host->h_nsmhandle;
 214         struct nsm_res  res;
 215         int status;
 216
 217         if (atomic_read(&nsm->sm_count) == 1
 218          && nsm->sm_monitored && !nsm->sm_sticky) {
 219                 dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
 220
 221                 status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res);
 222                 if (res.status != 0)
 223                         status = -EIO;
 224                 if (status < 0)
 225                         printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
 226                                         nsm->sm_name);
 227                 else
 228                         nsm->sm_monitored = 0;
 229         }
 230 }
 231
 232 static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
 233                                               const size_t len)
 234 {
 235         struct nsm_handle *nsm;
 236
 237         list_for_each_entry(nsm, &nsm_handles, sm_link)
 238                 if (strlen(nsm->sm_name) == len &&
 239                     memcmp(nsm->sm_name, hostname, len) == 0)
 240                         return nsm;
 241         return NULL;
 242 }
 243
 244 static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
 245 {
 246         struct nsm_handle *nsm;
 247
 248         list_for_each_entry(nsm, &nsm_handles, sm_link)
 249                 if (nlm_cmp_addr(nsm_addr(nsm), sap))
 250                         return nsm;
 251         return NULL;
 252 }
 253
 254 static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
 255 {
 256         struct nsm_handle *nsm;
 257
 258         list_for_each_entry(nsm, &nsm_handles, sm_link)
 259                 if (memcmp(nsm->sm_priv.data, priv->data,
 260                                         sizeof(priv->data)) == 0)
 261                         return nsm;
 262         return NULL;
 263 }
 264
 265 /*
 266  * Construct a unique cookie to match this nsm_handle to this monitored
 267  * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
 268  * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
 269  * requests.
 270  *
 271  * The NSM protocol requires that these cookies be unique while the
 272  * system is running.  We prefer a stronger requirement of making them
 273  * unique across reboots.  If user space bugs cause a stale cookie to
 274  * be sent to the kernel, it could cause the wrong host to lose its
 275  * lock state if cookies were not unique across reboots.
 276  *
 277  * The cookies are exposed only to local user space via loopback.  They
 278  * do not appear on the physical network.  If we want greater security
 279  * for some reason, nsm_init_private() could perform a one-way hash to
 280  * obscure the contents of the cookie.
 281  */
 282 static void nsm_init_private(struct nsm_handle *nsm)
 283 {
 284         u64 *p = (u64 *)&nsm->sm_priv.data;
 285         struct timespec ts;
 286         s64 ns;
 287
 288         ktime_get_ts(&ts);
 289         ns = timespec_to_ns(&ts);
 290         put_unaligned(ns, p);
 291         put_unaligned((unsigned long)nsm, p + 1);
 292 }
 293
 294 static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
 295                                             const size_t salen,
 296                                             const char *hostname,
 297                                             const size_t hostname_len)
 298 {
 299         struct nsm_handle *new;
 300
 301         new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
 302         if (unlikely(new == NULL))
 303                 return NULL;
 304
 305         atomic_set(&new->sm_count, 1);
 306         new->sm_name = (char *)(new + 1);
 307         memcpy(nsm_addr(new), sap, salen);
 308         new->sm_addrlen = salen;
 309         nsm_init_private(new);
 310         nsm_display_address((const struct sockaddr *)&new->sm_addr,
 311                                 new->sm_addrbuf, sizeof(new->sm_addrbuf));
 312         memcpy(new->sm_name, hostname, hostname_len);
 313         new->sm_name[hostname_len] = '\0';
 314
 315         return new;
 316 }
 317
 318 /**
 319  * nsm_get_handle - Find or create a cached nsm_handle
 320  * @sap: pointer to socket address of handle to find
 321  * @salen: length of socket address
 322  * @hostname: pointer to C string containing hostname to find
 323  * @hostname_len: length of C string
 324  *
 325  * Behavior is modulated by the global nsm_use_hostnames variable.
 326  *
 327  * Returns a cached nsm_handle after bumping its ref count, or
 328  * returns a fresh nsm_handle if a handle that matches @sap and/or
 329  * @hostname cannot be found in the handle cache.  Returns NULL if
 330  * an error occurs.
 331  */
 332 struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
 333                                   const size_t salen, const char *hostname,
 334                                   const size_t hostname_len)
 335 {
 336         struct nsm_handle *cached, *new = NULL;
 337
 338         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 339                 if (printk_ratelimit()) {
 340                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 341                                             "in NFS lock request\n",
 342                                 (int)hostname_len, hostname);
 343                 }
 344                 return NULL;
 345         }
 346
 347 retry:
 348         spin_lock(&nsm_lock);
 349
 350         if (nsm_use_hostnames && hostname != NULL)
 351                 cached = nsm_lookup_hostname(hostname, hostname_len);
 352         else
 353                 cached = nsm_lookup_addr(sap);
 354
 355         if (cached != NULL) {
 356                 atomic_inc(&cached->sm_count);
 357                 spin_unlock(&nsm_lock);
 358                 kfree(new);
 359                 dprintk("lockd: found nsm_handle for %s (%s), "
 360                                 "cnt %d\n", cached->sm_name,
 361                                 cached->sm_addrbuf,
 362                                 atomic_read(&cached->sm_count));
 363                 return cached;
 364         }
 365
 366         if (new != NULL) {
 367                 list_add(&new->sm_link, &nsm_handles);
 368                 spin_unlock(&nsm_lock);
 369                 dprintk("lockd: created nsm_handle for %s (%s)\n",
 370                                 new->sm_name, new->sm_addrbuf);
 371                 return new;
 372         }
 373
 374         spin_unlock(&nsm_lock);
 375
 376         new = nsm_create_handle(sap, salen, hostname, hostname_len);
 377         if (unlikely(new == NULL))
 378                 return NULL;
 379         goto retry;
 380 }
 381
 382 /**
 383  * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
 384  * @info: pointer to NLMPROC_SM_NOTIFY arguments
 385  *
 386  * Returns a matching nsm_handle if found in the nsm cache; the returned
 387  * nsm_handle's reference count is bumped and sm_monitored is cleared.
 388  * Otherwise returns NULL if some error occurred.
 389  */
 390 struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)
 391 {
 392         struct nsm_handle *cached;
 393
 394         spin_lock(&nsm_lock);
 395
 396         cached = nsm_lookup_priv(&info->priv);
 397         if (unlikely(cached == NULL)) {
 398                 spin_unlock(&nsm_lock);
 399                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 400                                 info->len, info->mon);
 401                 return cached;
 402         }
 403
 404         atomic_inc(&cached->sm_count);
 405         spin_unlock(&nsm_lock);
 406
 407         /*
 408          * During subsequent lock activity, force a fresh
 409          * notification to be set up for this host.
 410          */
 411         cached->sm_monitored = 0;
 412
 413         dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
 414                         cached->sm_name, cached->sm_addrbuf,
 415                         atomic_read(&cached->sm_count));
 416         return cached;
 417 }
 418
 419 /**
 420  * nsm_release - Release an NSM handle
 421  * @nsm: pointer to handle to be released
 422  *
 423  */
 424 void nsm_release(struct nsm_handle *nsm)
 425 {
 426         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 427                 list_del(&nsm->sm_link);
 428                 spin_unlock(&nsm_lock);
 429                 dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
 430                                 nsm->sm_name, nsm->sm_addrbuf);
 431                 kfree(nsm);
 432         }
 433 }
 434
 435 /*
 436  * XDR functions for NSM.
 437  *
 438  * See http://www.opengroup.org/ for details on the Network
 439  * Status Monitor wire protocol.
 440  */
 441
 442 static int encode_nsm_string(struct xdr_stream *xdr, const char *string)
 443 {
 444         const u32 len = strlen(string);
 445         __be32 *p;
 446
 447         if (unlikely(len > SM_MAXSTRLEN))
 448                 return -EIO;
 449         p = xdr_reserve_space(xdr, sizeof(u32) + len);
 450         if (unlikely(p == NULL))
 451                 return -EIO;
 452         xdr_encode_opaque(p, string, len);
 453         return 0;
 454 }
 455
 456 /*
 457  * "mon_name" specifies the host to be monitored.
 458  */
 459 static int encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
 460 {
 461         return encode_nsm_string(xdr, argp->mon_name);
 462 }
 463
 464 /*
 465  * The "my_id" argument specifies the hostname and RPC procedure
 466  * to be called when the status manager receives notification
 467  * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
 468  * has changed.
 469  */
 470 static int encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 471 {
 472         int status;
 473         __be32 *p;
 474
 475         status = encode_nsm_string(xdr, utsname()->nodename);
 476         if (unlikely(status != 0))
 477                 return status;
 478         p = xdr_reserve_space(xdr, 3 * sizeof(u32));
 479         if (unlikely(p == NULL))
 480                 return -EIO;
 481         *p++ = htonl(argp->prog);
 482         *p++ = htonl(argp->vers);
 483         *p++ = htonl(argp->proc);
 484         return 0;
 485 }
 486
 487 /*
 488  * The "mon_id" argument specifies the non-private arguments
 489  * of an NSMPROC_MON or NSMPROC_UNMON call.
 490  */
 491 static int encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
 492 {
 493         int status;
 494
 495         status = encode_mon_name(xdr, argp);
 496         if (unlikely(status != 0))
 497                 return status;
 498         return encode_my_id(xdr, argp);
 499 }
 500
 501 /*
 502  * The "priv" argument may contain private information required
 503  * by the NSMPROC_MON call. This information will be supplied in the
 504  * NLMPROC_SM_NOTIFY call.
 505  */
 506 static int encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
 507 {
 508         __be32 *p;
 509
 510         p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
 511         if (unlikely(p == NULL))
 512                 return -EIO;
 513         xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
 514         return 0;
 515 }
 516
 517 static int xdr_enc_mon(struct rpc_rqst *req, __be32 *p,
 518                        const struct nsm_args *argp)
 519 {
 520         struct xdr_stream xdr;
 521         int status;
 522
 523         xdr_init_encode(&xdr, &req->rq_snd_buf, p);
 524         status = encode_mon_id(&xdr, argp);
 525         if (unlikely(status))
 526                 return status;
 527         return encode_priv(&xdr, argp);
 528 }
 529
 530 static int xdr_enc_unmon(struct rpc_rqst *req, __be32 *p,
 531                          const struct nsm_args *argp)
 532 {
 533         struct xdr_stream xdr;
 534
 535         xdr_init_encode(&xdr, &req->rq_snd_buf, p);
 536         return encode_mon_id(&xdr, argp);
 537 }
 538
 539 static int xdr_dec_stat_res(struct rpc_rqst *rqstp, __be32 *p,
 540                             struct nsm_res *resp)
 541 {
 542         struct xdr_stream xdr;
 543
 544         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
 545         p = xdr_inline_decode(&xdr, 2 * sizeof(u32));
 546         if (unlikely(p == NULL))
 547                 return -EIO;
 548         resp->status = ntohl(*p++);
 549         resp->state = ntohl(*p);
 550
 551         dprintk("lockd: xdr_dec_stat_res status %d state %d\n",
 552                         resp->status, resp->state);
 553         return 0;
 554 }
 555
 556 static int xdr_dec_stat(struct rpc_rqst *rqstp, __be32 *p,
 557                         struct nsm_res *resp)
 558 {
 559         struct xdr_stream xdr;
 560
 561         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
 562         p = xdr_inline_decode(&xdr, sizeof(u32));
 563         if (unlikely(p == NULL))
 564                 return -EIO;
 565         resp->state = ntohl(*p);
 566
 567         dprintk("lockd: xdr_dec_stat state %d\n", resp->state);
 568         return 0;
 569 }
 570
 571 #define SM_my_name_sz   (1+XDR_QUADLEN(SM_MAXSTRLEN))
 572 #define SM_my_id_sz     (SM_my_name_sz+3)
 573 #define SM_mon_name_sz  (1+XDR_QUADLEN(SM_MAXSTRLEN))
 574 #define SM_mon_id_sz    (SM_mon_name_sz+SM_my_id_sz)
 575 #define SM_priv_sz      (XDR_QUADLEN(SM_PRIV_SIZE))
 576 #define SM_mon_sz       (SM_mon_id_sz+SM_priv_sz)
 577 #define SM_monres_sz    2
 578 #define SM_unmonres_sz  1
 579
 580 static struct rpc_procinfo      nsm_procedures[] = {
 581 [NSMPROC_MON] = {
 582                 .p_proc         = NSMPROC_MON,
 583                 .p_encode       = (kxdrproc_t)xdr_enc_mon,
 584                 .p_decode       = (kxdrproc_t)xdr_dec_stat_res,
 585                 .p_arglen       = SM_mon_sz,
 586                 .p_replen       = SM_monres_sz,
 587                 .p_statidx      = NSMPROC_MON,
 588                 .p_name         = "MONITOR",
 589         },
 590 [NSMPROC_UNMON] = {
 591                 .p_proc         = NSMPROC_UNMON,
 592                 .p_encode       = (kxdrproc_t)xdr_enc_unmon,
 593                 .p_decode       = (kxdrproc_t)xdr_dec_stat,
 594                 .p_arglen       = SM_mon_id_sz,
 595                 .p_replen       = SM_unmonres_sz,
 596                 .p_statidx      = NSMPROC_UNMON,
 597                 .p_name         = "UNMONITOR",
 598         },
 599 };
 600
 601 static struct rpc_version       nsm_version1 = {
 602                 .number         = 1,
 603                 .nrprocs        = ARRAY_SIZE(nsm_procedures),
 604                 .procs          = nsm_procedures
 605 };
 606
 607 static struct rpc_version *     nsm_version[] = {
 608         [1] = &nsm_version1,
 609 };
 610
 611 static struct rpc_stat          nsm_stats;
 612
 613 static struct rpc_program       nsm_program = {
 614                 .name           = "statd",
 615                 .number         = NSM_PROGRAM,
 616                 .nrvers         = ARRAY_SIZE(nsm_version),
 617                 .version        = nsm_version,
 618                 .stats          = &nsm_stats
 619 };