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