fs/lockd/host.c

   1 /*
   2  * linux/fs/lockd/host.c
   3  *
   4  * Management for NLM peer hosts. The nlm_host struct is shared
   5  * between client and server implementation. The only reason to
   6  * do so is to reduce code bloat.
   7  *
   8  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/slab.h>
  13 #include <linux/in.h>
  14 #include <linux/in6.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/sunrpc/svc.h>
  17 #include <linux/lockd/lockd.h>
  18 #include <linux/mutex.h>
  19
  20 #include <net/ipv6.h>
  21
  22 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  23 #define NLM_HOST_NRHASH         32
  24 #define NLM_HOST_REBIND         (60 * HZ)
  25 #define NLM_HOST_EXPIRE         (300 * HZ)
  26 #define NLM_HOST_COLLECT        (120 * HZ)
  27
  28 static struct hlist_head        nlm_server_hosts[NLM_HOST_NRHASH];
  29 static struct hlist_head        nlm_client_hosts[NLM_HOST_NRHASH];
  30
  31 #define for_each_host(host, pos, chain, table) \
  32         for ((chain) = (table); \
  33              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
  34                 hlist_for_each_entry((host), (pos), (chain), h_hash)
  35
  36 #define for_each_host_safe(host, pos, next, chain, table) \
  37         for ((chain) = (table); \
  38              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
  39                 hlist_for_each_entry_safe((host), (pos), (next), \
  40                                                 (chain), h_hash)
  41
  42 static unsigned long            next_gc;
  43 static unsigned long            nrhosts;
  44 static DEFINE_MUTEX(nlm_host_mutex);
  45
  46 static void                     nlm_gc_hosts(void);
  47
  48 struct nlm_lookup_host_info {
  49         const int               server;         /* search for server|client */
  50         const struct sockaddr   *sap;           /* address to search for */
  51         const size_t            salen;          /* it's length */
  52         const unsigned short    protocol;       /* transport to search for*/
  53         const u32               version;        /* NLM version to search for */
  54         const char              *hostname;      /* remote's hostname */
  55         const size_t            hostname_len;   /* it's length */
  56         const int               noresvport;     /* use non-priv port */
  57 };
  58
  59 /*
  60  * Hash function must work well on big- and little-endian platforms
  61  */
  62 static unsigned int __nlm_hash32(const __be32 n)
  63 {
  64         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  65         return hash ^ (hash >> 8);
  66 }
  67
  68 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  69 {
  70         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  71         return __nlm_hash32(sin->sin_addr.s_addr);
  72 }
  73
  74 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  75 {
  76         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  77         const struct in6_addr addr = sin6->sin6_addr;
  78         return __nlm_hash32(addr.s6_addr32[0]) ^
  79                __nlm_hash32(addr.s6_addr32[1]) ^
  80                __nlm_hash32(addr.s6_addr32[2]) ^
  81                __nlm_hash32(addr.s6_addr32[3]);
  82 }
  83
  84 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  85 {
  86         unsigned int hash;
  87
  88         switch (sap->sa_family) {
  89         case AF_INET:
  90                 hash = __nlm_hash_addr4(sap);
  91                 break;
  92         case AF_INET6:
  93                 hash = __nlm_hash_addr6(sap);
  94                 break;
  95         default:
  96                 hash = 0;
  97         }
  98         return hash & (NLM_HOST_NRHASH - 1);
  99 }
 100
 101 /*
 102  * Allocate and initialize an nlm_host.  Common to both client and server.
 103  */
 104 static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
 105                                        struct nsm_handle *nsm)
 106 {
 107         struct nlm_host *host = NULL;
 108         unsigned long now = jiffies;
 109
 110         if (nsm != NULL)
 111                 atomic_inc(&nsm->sm_count);
 112         else {
 113                 host = NULL;
 114                 nsm = nsm_get_handle(ni->sap, ni->salen,
 115                                         ni->hostname, ni->hostname_len);
 116                 if (unlikely(nsm == NULL)) {
 117                         dprintk("lockd: %s failed; no nsm handle\n",
 118                                 __func__);
 119                         goto out;
 120                 }
 121         }
 122
 123         host = kmalloc(sizeof(*host), GFP_KERNEL);
 124         if (unlikely(host == NULL)) {
 125                 dprintk("lockd: %s failed; no memory\n", __func__);
 126                 nsm_release(nsm);
 127                 goto out;
 128         }
 129
 130         memcpy(nlm_addr(host), ni->sap, ni->salen);
 131         host->h_addrlen    = ni->salen;
 132         rpc_set_port(nlm_addr(host), 0);
 133         host->h_srcaddrlen = 0;
 134
 135         host->h_rpcclnt    = NULL;
 136         host->h_name       = nsm->sm_name;
 137         host->h_version    = ni->version;
 138         host->h_proto      = ni->protocol;
 139         host->h_reclaiming = 0;
 140         host->h_server     = ni->server;
 141         host->h_noresvport = ni->noresvport;
 142         host->h_inuse      = 0;
 143         init_waitqueue_head(&host->h_gracewait);
 144         init_rwsem(&host->h_rwsem);
 145         host->h_state      = 0;
 146         host->h_nsmstate   = 0;
 147         host->h_pidcount   = 0;
 148         atomic_set(&host->h_count, 1);
 149         mutex_init(&host->h_mutex);
 150         host->h_nextrebind = now + NLM_HOST_REBIND;
 151         host->h_expires    = now + NLM_HOST_EXPIRE;
 152         INIT_LIST_HEAD(&host->h_lockowners);
 153         spin_lock_init(&host->h_lock);
 154         INIT_LIST_HEAD(&host->h_granted);
 155         INIT_LIST_HEAD(&host->h_reclaim);
 156         host->h_nsmhandle  = nsm;
 157         host->h_addrbuf    = nsm->sm_addrbuf;
 158
 159 out:
 160         return host;
 161 }
 162
 163 /*
 164  * Destroy an nlm_host and free associated resources
 165  *
 166  * Caller must hold nlm_host_mutex.
 167  */
 168 static void nlm_destroy_host_locked(struct nlm_host *host)
 169 {
 170         struct rpc_clnt *clnt;
 171
 172         dprintk("lockd: destroy host %s\n", host->h_name);
 173
 174         BUG_ON(!list_empty(&host->h_lockowners));
 175         BUG_ON(atomic_read(&host->h_count));
 176
 177         hlist_del_init(&host->h_hash);
 178
 179         nsm_unmonitor(host);
 180         nsm_release(host->h_nsmhandle);
 181
 182         clnt = host->h_rpcclnt;
 183         if (clnt != NULL)
 184                 rpc_shutdown_client(clnt);
 185         kfree(host);
 186
 187         nrhosts--;
 188 }
 189
 190 /**
 191  * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
 192  * @sap: network address of server
 193  * @salen: length of server address
 194  * @protocol: transport protocol to use
 195  * @version: NLM protocol version
 196  * @hostname: '\0'-terminated hostname of server
 197  * @noresvport: 1 if non-privileged port should be used
 198  *
 199  * Returns an nlm_host structure that matches the passed-in
 200  * [server address, transport protocol, NLM version, server hostname].
 201  * If one doesn't already exist in the host cache, a new handle is
 202  * created and returned.
 203  */
 204 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
 205                                      const size_t salen,
 206                                      const unsigned short protocol,
 207                                      const u32 version,
 208                                      const char *hostname,
 209                                      int noresvport)
 210 {
 211         struct nlm_lookup_host_info ni = {
 212                 .server         = 0,
 213                 .sap            = sap,
 214                 .salen          = salen,
 215                 .protocol       = protocol,
 216                 .version        = version,
 217                 .hostname       = hostname,
 218                 .hostname_len   = strlen(hostname),
 219                 .noresvport     = noresvport,
 220         };
 221         struct hlist_head *chain;
 222         struct hlist_node *pos;
 223         struct nlm_host *host;
 224         struct nsm_handle *nsm = NULL;
 225
 226         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
 227                         (hostname ? hostname : "<none>"), version,
 228                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
 229
 230         mutex_lock(&nlm_host_mutex);
 231
 232         chain = &nlm_client_hosts[nlm_hash_address(sap)];
 233         hlist_for_each_entry(host, pos, chain, h_hash) {
 234                 if (!rpc_cmp_addr(nlm_addr(host), sap))
 235                         continue;
 236
 237                 /* Same address. Share an NSM handle if we already have one */
 238                 if (nsm == NULL)
 239                         nsm = host->h_nsmhandle;
 240
 241                 if (host->h_proto != protocol)
 242                         continue;
 243                 if (host->h_version != version)
 244                         continue;
 245
 246                 nlm_get_host(host);
 247                 dprintk("lockd: %s found host %s (%s)\n", __func__,
 248                         host->h_name, host->h_addrbuf);
 249                 goto out;
 250         }
 251
 252         host = nlm_alloc_host(&ni, nsm);
 253         if (unlikely(host == NULL))
 254                 goto out;
 255
 256         hlist_add_head(&host->h_hash, chain);
 257         nrhosts++;
 258
 259         dprintk("lockd: %s created host %s (%s)\n", __func__,
 260                 host->h_name, host->h_addrbuf);
 261
 262 out:
 263         mutex_unlock(&nlm_host_mutex);
 264         return host;
 265 }
 266
 267 /**
 268  * nlmclnt_release_host - release client nlm_host
 269  * @host: nlm_host to release
 270  *
 271  */
 272 void nlmclnt_release_host(struct nlm_host *host)
 273 {
 274         if (host == NULL)
 275                 return;
 276
 277         dprintk("lockd: release client host %s\n", host->h_name);
 278
 279         BUG_ON(atomic_read(&host->h_count) < 0);
 280         BUG_ON(host->h_server);
 281
 282         if (atomic_dec_and_test(&host->h_count)) {
 283                 BUG_ON(!list_empty(&host->h_lockowners));
 284                 BUG_ON(!list_empty(&host->h_granted));
 285                 BUG_ON(!list_empty(&host->h_reclaim));
 286
 287                 mutex_lock(&nlm_host_mutex);
 288                 nlm_destroy_host_locked(host);
 289                 mutex_unlock(&nlm_host_mutex);
 290         }
 291 }
 292
 293 /**
 294  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
 295  * @rqstp: incoming NLM request
 296  * @hostname: name of client host
 297  * @hostname_len: length of client hostname
 298  *
 299  * Returns an nlm_host structure that matches the [client address,
 300  * transport protocol, NLM version, client hostname] of the passed-in
 301  * NLM request.  If one doesn't already exist in the host cache, a
 302  * new handle is created and returned.
 303  *
 304  * Before possibly creating a new nlm_host, construct a sockaddr
 305  * for a specific source address in case the local system has
 306  * multiple network addresses.  The family of the address in
 307  * rq_daddr is guaranteed to be the same as the family of the
 308  * address in rq_addr, so it's safe to use the same family for
 309  * the source address.
 310  */
 311 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
 312                                     const char *hostname,
 313                                     const size_t hostname_len)
 314 {
 315         struct hlist_head *chain;
 316         struct hlist_node *pos;
 317         struct nlm_host *host = NULL;
 318         struct nsm_handle *nsm = NULL;
 319         struct sockaddr_in sin = {
 320                 .sin_family     = AF_INET,
 321         };
 322         struct sockaddr_in6 sin6 = {
 323                 .sin6_family    = AF_INET6,
 324         };
 325         struct sockaddr *src_sap;
 326         size_t src_len = rqstp->rq_addrlen;
 327         struct nlm_lookup_host_info ni = {
 328                 .server         = 1,
 329                 .sap            = svc_addr(rqstp),
 330                 .salen          = rqstp->rq_addrlen,
 331                 .protocol       = rqstp->rq_prot,
 332                 .version        = rqstp->rq_vers,
 333                 .hostname       = hostname,
 334                 .hostname_len   = hostname_len,
 335         };
 336
 337         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
 338                         (int)hostname_len, hostname, rqstp->rq_vers,
 339                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 340
 341         mutex_lock(&nlm_host_mutex);
 342
 343         switch (ni.sap->sa_family) {
 344         case AF_INET:
 345                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
 346                 src_sap = (struct sockaddr *)&sin;
 347                 break;
 348         case AF_INET6:
 349                 ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
 350                 src_sap = (struct sockaddr *)&sin6;
 351                 break;
 352         default:
 353                 dprintk("lockd: %s failed; unrecognized address family\n",
 354                         __func__);
 355                 goto out;
 356         }
 357
 358         if (time_after_eq(jiffies, next_gc))
 359                 nlm_gc_hosts();
 360
 361         chain = &nlm_server_hosts[nlm_hash_address(ni.sap)];
 362         hlist_for_each_entry(host, pos, chain, h_hash) {
 363                 if (!rpc_cmp_addr(nlm_addr(host), ni.sap))
 364                         continue;
 365
 366                 /* Same address. Share an NSM handle if we already have one */
 367                 if (nsm == NULL)
 368                         nsm = host->h_nsmhandle;
 369
 370                 if (host->h_proto != ni.protocol)
 371                         continue;
 372                 if (host->h_version != ni.version)
 373                         continue;
 374                 if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap))
 375                         continue;
 376
 377                 /* Move to head of hash chain. */
 378                 hlist_del(&host->h_hash);
 379                 hlist_add_head(&host->h_hash, chain);
 380
 381                 nlm_get_host(host);
 382                 dprintk("lockd: %s found host %s (%s)\n",
 383                         __func__, host->h_name, host->h_addrbuf);
 384                 goto out;
 385         }
 386
 387         host = nlm_alloc_host(&ni, nsm);
 388         if (unlikely(host == NULL))
 389                 goto out;
 390
 391         memcpy(nlm_srcaddr(host), src_sap, src_len);
 392         host->h_srcaddrlen = src_len;
 393         hlist_add_head(&host->h_hash, chain);
 394         nrhosts++;
 395
 396         dprintk("lockd: %s created host %s (%s)\n",
 397                 __func__, host->h_name, host->h_addrbuf);
 398
 399 out:
 400         mutex_unlock(&nlm_host_mutex);
 401         return host;
 402 }
 403
 404 /**
 405  * nlmsvc_release_host - release server nlm_host
 406  * @host: nlm_host to release
 407  *
 408  * Host is destroyed later in nlm_gc_host().
 409  */
 410 void nlmsvc_release_host(struct nlm_host *host)
 411 {
 412         if (host == NULL)
 413                 return;
 414
 415         dprintk("lockd: release server host %s\n", host->h_name);
 416
 417         BUG_ON(atomic_read(&host->h_count) < 0);
 418         BUG_ON(!host->h_server);
 419         atomic_dec(&host->h_count);
 420 }
 421
 422 /*
 423  * Create the NLM RPC client for an NLM peer
 424  */
 425 struct rpc_clnt *
 426 nlm_bind_host(struct nlm_host *host)
 427 {
 428         struct rpc_clnt *clnt;
 429
 430         dprintk("lockd: nlm_bind_host %s (%s)\n",
 431                         host->h_name, host->h_addrbuf);
 432
 433         /* Lock host handle */
 434         mutex_lock(&host->h_mutex);
 435
 436         /* If we've already created an RPC client, check whether
 437          * RPC rebind is required
 438          */
 439         if ((clnt = host->h_rpcclnt) != NULL) {
 440                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 441                         rpc_force_rebind(clnt);
 442                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 443                         dprintk("lockd: next rebind in %lu jiffies\n",
 444                                         host->h_nextrebind - jiffies);
 445                 }
 446         } else {
 447                 unsigned long increment = nlmsvc_timeout;
 448                 struct rpc_timeout timeparms = {
 449                         .to_initval     = increment,
 450                         .to_increment   = increment,
 451                         .to_maxval      = increment * 6UL,
 452                         .to_retries     = 5U,
 453                 };
 454                 struct rpc_create_args args = {
 455                         .net            = &init_net,
 456                         .protocol       = host->h_proto,
 457                         .address        = nlm_addr(host),
 458                         .addrsize       = host->h_addrlen,
 459                         .timeout        = &timeparms,
 460                         .servername     = host->h_name,
 461                         .program        = &nlm_program,
 462                         .version        = host->h_version,
 463                         .authflavor     = RPC_AUTH_UNIX,
 464                         .flags          = (RPC_CLNT_CREATE_NOPING |
 465                                            RPC_CLNT_CREATE_AUTOBIND),
 466                 };
 467
 468                 /*
 469                  * lockd retries server side blocks automatically so we want
 470                  * those to be soft RPC calls. Client side calls need to be
 471                  * hard RPC tasks.
 472                  */
 473                 if (!host->h_server)
 474                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 475                 if (host->h_noresvport)
 476                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 477                 if (host->h_srcaddrlen)
 478                         args.saddress = nlm_srcaddr(host);
 479
 480                 clnt = rpc_create(&args);
 481                 if (!IS_ERR(clnt))
 482                         host->h_rpcclnt = clnt;
 483                 else {
 484                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 485                         clnt = NULL;
 486                 }
 487         }
 488
 489         mutex_unlock(&host->h_mutex);
 490         return clnt;
 491 }
 492
 493 /*
 494  * Force a portmap lookup of the remote lockd port
 495  */
 496 void
 497 nlm_rebind_host(struct nlm_host *host)
 498 {
 499         dprintk("lockd: rebind host %s\n", host->h_name);
 500         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 501                 rpc_force_rebind(host->h_rpcclnt);
 502                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 503         }
 504 }
 505
 506 /*
 507  * Increment NLM host count
 508  */
 509 struct nlm_host * nlm_get_host(struct nlm_host *host)
 510 {
 511         if (host) {
 512                 dprintk("lockd: get host %s\n", host->h_name);
 513                 atomic_inc(&host->h_count);
 514                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 515         }
 516         return host;
 517 }
 518
 519 static struct nlm_host *next_host_state(struct hlist_head *cache,
 520                                         struct nsm_handle *nsm,
 521                                         const struct nlm_reboot *info)
 522 {
 523         struct nlm_host *host = NULL;
 524         struct hlist_head *chain;
 525         struct hlist_node *pos;
 526
 527         mutex_lock(&nlm_host_mutex);
 528         for_each_host(host, pos, chain, cache) {
 529                 if (host->h_nsmhandle == nsm
 530                     && host->h_nsmstate != info->state) {
 531                         host->h_nsmstate = info->state;
 532                         host->h_state++;
 533
 534                         nlm_get_host(host);
 535                         goto out;
 536                 }
 537         }
 538 out:
 539         mutex_unlock(&nlm_host_mutex);
 540         return host;
 541 }
 542
 543 /**
 544  * nlm_host_rebooted - Release all resources held by rebooted host
 545  * @info: pointer to decoded results of NLM_SM_NOTIFY call
 546  *
 547  * We were notified that the specified host has rebooted.  Release
 548  * all resources held by that peer.
 549  */
 550 void nlm_host_rebooted(const struct nlm_reboot *info)
 551 {
 552         struct nsm_handle *nsm;
 553         struct nlm_host *host;
 554
 555         nsm = nsm_reboot_lookup(info);
 556         if (unlikely(nsm == NULL))
 557                 return;
 558
 559         /* Mark all hosts tied to this NSM state as having rebooted.
 560          * We run the loop repeatedly, because we drop the host table
 561          * lock for this.
 562          * To avoid processing a host several times, we match the nsmstate.
 563          */
 564         while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) {
 565                 nlmsvc_free_host_resources(host);
 566                 nlmsvc_release_host(host);
 567         }
 568         while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
 569                 nlmclnt_recovery(host);
 570                 nlmclnt_release_host(host);
 571         }
 572
 573         nsm_release(nsm);
 574 }
 575
 576 /*
 577  * Shut down the hosts module.
 578  * Note that this routine is called only at server shutdown time.
 579  */
 580 void
 581 nlm_shutdown_hosts(void)
 582 {
 583         struct hlist_head *chain;
 584         struct hlist_node *pos;
 585         struct nlm_host *host;
 586
 587         dprintk("lockd: shutting down host module\n");
 588         mutex_lock(&nlm_host_mutex);
 589
 590         /* First, make all hosts eligible for gc */
 591         dprintk("lockd: nuking all hosts...\n");
 592         for_each_host(host, pos, chain, nlm_server_hosts) {
 593                 host->h_expires = jiffies - 1;
 594                 if (host->h_rpcclnt) {
 595                         rpc_shutdown_client(host->h_rpcclnt);
 596                         host->h_rpcclnt = NULL;
 597                 }
 598         }
 599
 600         /* Then, perform a garbage collection pass */
 601         nlm_gc_hosts();
 602         mutex_unlock(&nlm_host_mutex);
 603
 604         /* complain if any hosts are left */
 605         if (nrhosts != 0) {
 606                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 607                 dprintk("lockd: %lu hosts left:\n", nrhosts);
 608                 for_each_host(host, pos, chain, nlm_server_hosts) {
 609                         dprintk("       %s (cnt %d use %d exp %ld)\n",
 610                                 host->h_name, atomic_read(&host->h_count),
 611                                 host->h_inuse, host->h_expires);
 612                 }
 613         }
 614 }
 615
 616 /*
 617  * Garbage collect any unused NLM hosts.
 618  * This GC combines reference counting for async operations with
 619  * mark & sweep for resources held by remote clients.
 620  */
 621 static void
 622 nlm_gc_hosts(void)
 623 {
 624         struct hlist_head *chain;
 625         struct hlist_node *pos, *next;
 626         struct nlm_host *host;
 627
 628         dprintk("lockd: host garbage collection\n");
 629         for_each_host(host, pos, chain, nlm_server_hosts)
 630                 host->h_inuse = 0;
 631
 632         /* Mark all hosts that hold locks, blocks or shares */
 633         nlmsvc_mark_resources();
 634
 635         for_each_host_safe(host, pos, next, chain, nlm_server_hosts) {
 636                 if (atomic_read(&host->h_count) || host->h_inuse
 637                  || time_before(jiffies, host->h_expires)) {
 638                         dprintk("nlm_gc_hosts skipping %s "
 639                                 "(cnt %d use %d exp %ld)\n",
 640                                 host->h_name, atomic_read(&host->h_count),
 641                                 host->h_inuse, host->h_expires);
 642                         continue;
 643                 }
 644                 nlm_destroy_host_locked(host);
 645         }
 646
 647         next_gc = jiffies + NLM_HOST_COLLECT;
 648 }