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 <linux/sunrpc/svc_xprt.h>
  21
  22 #include <net/ipv6.h>
  23
  24 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  25 #define NLM_HOST_NRHASH         32
  26 #define NLM_HOST_REBIND         (60 * HZ)
  27 #define NLM_HOST_EXPIRE         (300 * HZ)
  28 #define NLM_HOST_COLLECT        (120 * HZ)
  29
  30 static struct hlist_head        nlm_server_hosts[NLM_HOST_NRHASH];
  31 static struct hlist_head        nlm_client_hosts[NLM_HOST_NRHASH];
  32
  33 #define for_each_host(host, pos, chain, table) \
  34         for ((chain) = (table); \
  35              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
  36                 hlist_for_each_entry((host), (pos), (chain), h_hash)
  37
  38 #define for_each_host_safe(host, pos, next, chain, table) \
  39         for ((chain) = (table); \
  40              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
  41                 hlist_for_each_entry_safe((host), (pos), (next), \
  42                                                 (chain), h_hash)
  43
  44 static unsigned long            next_gc;
  45 static unsigned long            nrhosts;
  46 static DEFINE_MUTEX(nlm_host_mutex);
  47
  48 static void                     nlm_gc_hosts(void);
  49
  50 struct nlm_lookup_host_info {
  51         const int               server;         /* search for server|client */
  52         const struct sockaddr   *sap;           /* address to search for */
  53         const size_t            salen;          /* it's length */
  54         const unsigned short    protocol;       /* transport to search for*/
  55         const u32               version;        /* NLM version to search for */
  56         const char              *hostname;      /* remote's hostname */
  57         const size_t            hostname_len;   /* it's length */
  58         const int               noresvport;     /* use non-priv port */
  59         struct net              *net;           /* network namespace to bind */
  60 };
  61
  62 /*
  63  * Hash function must work well on big- and little-endian platforms
  64  */
  65 static unsigned int __nlm_hash32(const __be32 n)
  66 {
  67         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  68         return hash ^ (hash >> 8);
  69 }
  70
  71 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  72 {
  73         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  74         return __nlm_hash32(sin->sin_addr.s_addr);
  75 }
  76
  77 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  78 {
  79         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  80         const struct in6_addr addr = sin6->sin6_addr;
  81         return __nlm_hash32(addr.s6_addr32[0]) ^
  82                __nlm_hash32(addr.s6_addr32[1]) ^
  83                __nlm_hash32(addr.s6_addr32[2]) ^
  84                __nlm_hash32(addr.s6_addr32[3]);
  85 }
  86
  87 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  88 {
  89         unsigned int hash;
  90
  91         switch (sap->sa_family) {
  92         case AF_INET:
  93                 hash = __nlm_hash_addr4(sap);
  94                 break;
  95         case AF_INET6:
  96                 hash = __nlm_hash_addr6(sap);
  97                 break;
  98         default:
  99                 hash = 0;
 100         }
 101         return hash & (NLM_HOST_NRHASH - 1);
 102 }
 103
 104 /*
 105  * Allocate and initialize an nlm_host.  Common to both client and server.
 106  */
 107 static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
 108                                        struct nsm_handle *nsm)
 109 {
 110         struct nlm_host *host = NULL;
 111         unsigned long now = jiffies;
 112
 113         if (nsm != NULL)
 114                 atomic_inc(&nsm->sm_count);
 115         else {
 116                 host = NULL;
 117                 nsm = nsm_get_handle(ni->sap, ni->salen,
 118                                         ni->hostname, ni->hostname_len);
 119                 if (unlikely(nsm == NULL)) {
 120                         dprintk("lockd: %s failed; no nsm handle\n",
 121                                 __func__);
 122                         goto out;
 123                 }
 124         }
 125
 126         host = kmalloc(sizeof(*host), GFP_KERNEL);
 127         if (unlikely(host == NULL)) {
 128                 dprintk("lockd: %s failed; no memory\n", __func__);
 129                 nsm_release(nsm);
 130                 goto out;
 131         }
 132
 133         memcpy(nlm_addr(host), ni->sap, ni->salen);
 134         host->h_addrlen    = ni->salen;
 135         rpc_set_port(nlm_addr(host), 0);
 136         host->h_srcaddrlen = 0;
 137
 138         host->h_rpcclnt    = NULL;
 139         host->h_name       = nsm->sm_name;
 140         host->h_version    = ni->version;
 141         host->h_proto      = ni->protocol;
 142         host->h_reclaiming = 0;
 143         host->h_server     = ni->server;
 144         host->h_noresvport = ni->noresvport;
 145         host->h_inuse      = 0;
 146         init_waitqueue_head(&host->h_gracewait);
 147         init_rwsem(&host->h_rwsem);
 148         host->h_state      = 0;
 149         host->h_nsmstate   = 0;
 150         host->h_pidcount   = 0;
 151         atomic_set(&host->h_count, 1);
 152         mutex_init(&host->h_mutex);
 153         host->h_nextrebind = now + NLM_HOST_REBIND;
 154         host->h_expires    = now + NLM_HOST_EXPIRE;
 155         INIT_LIST_HEAD(&host->h_lockowners);
 156         spin_lock_init(&host->h_lock);
 157         INIT_LIST_HEAD(&host->h_granted);
 158         INIT_LIST_HEAD(&host->h_reclaim);
 159         host->h_nsmhandle  = nsm;
 160         host->h_addrbuf    = nsm->sm_addrbuf;
 161         host->net          = ni->net;
 162
 163 out:
 164         return host;
 165 }
 166
 167 /*
 168  * Destroy an nlm_host and free associated resources
 169  *
 170  * Caller must hold nlm_host_mutex.
 171  */
 172 static void nlm_destroy_host_locked(struct nlm_host *host)
 173 {
 174         struct rpc_clnt *clnt;
 175
 176         dprintk("lockd: destroy host %s\n", host->h_name);
 177
 178         BUG_ON(!list_empty(&host->h_lockowners));
 179         BUG_ON(atomic_read(&host->h_count));
 180
 181         hlist_del_init(&host->h_hash);
 182
 183         nsm_unmonitor(host);
 184         nsm_release(host->h_nsmhandle);
 185
 186         clnt = host->h_rpcclnt;
 187         if (clnt != NULL)
 188                 rpc_shutdown_client(clnt);
 189         kfree(host);
 190
 191         nrhosts--;
 192 }
 193
 194 /**
 195  * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
 196  * @sap: network address of server
 197  * @salen: length of server address
 198  * @protocol: transport protocol to use
 199  * @version: NLM protocol version
 200  * @hostname: '\0'-terminated hostname of server
 201  * @noresvport: 1 if non-privileged port should be used
 202  *
 203  * Returns an nlm_host structure that matches the passed-in
 204  * [server address, transport protocol, NLM version, server hostname].
 205  * If one doesn't already exist in the host cache, a new handle is
 206  * created and returned.
 207  */
 208 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
 209                                      const size_t salen,
 210                                      const unsigned short protocol,
 211                                      const u32 version,
 212                                      const char *hostname,
 213                                      int noresvport,
 214                                      struct net *net)
 215 {
 216         struct nlm_lookup_host_info ni = {
 217                 .server         = 0,
 218                 .sap            = sap,
 219                 .salen          = salen,
 220                 .protocol       = protocol,
 221                 .version        = version,
 222                 .hostname       = hostname,
 223                 .hostname_len   = strlen(hostname),
 224                 .noresvport     = noresvport,
 225                 .net            = net,
 226         };
 227         struct hlist_head *chain;
 228         struct hlist_node *pos;
 229         struct nlm_host *host;
 230         struct nsm_handle *nsm = NULL;
 231
 232         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
 233                         (hostname ? hostname : "<none>"), version,
 234                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
 235
 236         mutex_lock(&nlm_host_mutex);
 237
 238         chain = &nlm_client_hosts[nlm_hash_address(sap)];
 239         hlist_for_each_entry(host, pos, chain, h_hash) {
 240                 if (host->net != net)
 241                         continue;
 242                 if (!rpc_cmp_addr(nlm_addr(host), sap))
 243                         continue;
 244
 245                 /* Same address. Share an NSM handle if we already have one */
 246                 if (nsm == NULL)
 247                         nsm = host->h_nsmhandle;
 248
 249                 if (host->h_proto != protocol)
 250                         continue;
 251                 if (host->h_version != version)
 252                         continue;
 253
 254                 nlm_get_host(host);
 255                 dprintk("lockd: %s found host %s (%s)\n", __func__,
 256                         host->h_name, host->h_addrbuf);
 257                 goto out;
 258         }
 259
 260         host = nlm_alloc_host(&ni, nsm);
 261         if (unlikely(host == NULL))
 262                 goto out;
 263
 264         hlist_add_head(&host->h_hash, chain);
 265         nrhosts++;
 266
 267         dprintk("lockd: %s created host %s (%s)\n", __func__,
 268                 host->h_name, host->h_addrbuf);
 269
 270 out:
 271         mutex_unlock(&nlm_host_mutex);
 272         return host;
 273 }
 274
 275 /**
 276  * nlmclnt_release_host - release client nlm_host
 277  * @host: nlm_host to release
 278  *
 279  */
 280 void nlmclnt_release_host(struct nlm_host *host)
 281 {
 282         if (host == NULL)
 283                 return;
 284
 285         dprintk("lockd: release client host %s\n", host->h_name);
 286
 287         BUG_ON(atomic_read(&host->h_count) < 0);
 288         BUG_ON(host->h_server);
 289
 290         if (atomic_dec_and_test(&host->h_count)) {
 291                 BUG_ON(!list_empty(&host->h_lockowners));
 292                 BUG_ON(!list_empty(&host->h_granted));
 293                 BUG_ON(!list_empty(&host->h_reclaim));
 294
 295                 mutex_lock(&nlm_host_mutex);
 296                 nlm_destroy_host_locked(host);
 297                 mutex_unlock(&nlm_host_mutex);
 298         }
 299 }
 300
 301 /**
 302  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
 303  * @rqstp: incoming NLM request
 304  * @hostname: name of client host
 305  * @hostname_len: length of client hostname
 306  *
 307  * Returns an nlm_host structure that matches the [client address,
 308  * transport protocol, NLM version, client hostname] of the passed-in
 309  * NLM request.  If one doesn't already exist in the host cache, a
 310  * new handle is created and returned.
 311  *
 312  * Before possibly creating a new nlm_host, construct a sockaddr
 313  * for a specific source address in case the local system has
 314  * multiple network addresses.  The family of the address in
 315  * rq_daddr is guaranteed to be the same as the family of the
 316  * address in rq_addr, so it's safe to use the same family for
 317  * the source address.
 318  */
 319 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
 320                                     const char *hostname,
 321                                     const size_t hostname_len)
 322 {
 323         struct hlist_head *chain;
 324         struct hlist_node *pos;
 325         struct nlm_host *host = NULL;
 326         struct nsm_handle *nsm = NULL;
 327         struct sockaddr *src_sap = svc_daddr(rqstp);
 328         size_t src_len = rqstp->rq_daddrlen;
 329         struct net *net = rqstp->rq_xprt->xpt_net;
 330         struct nlm_lookup_host_info ni = {
 331                 .server         = 1,
 332                 .sap            = svc_addr(rqstp),
 333                 .salen          = rqstp->rq_addrlen,
 334                 .protocol       = rqstp->rq_prot,
 335                 .version        = rqstp->rq_vers,
 336                 .hostname       = hostname,
 337                 .hostname_len   = hostname_len,
 338                 .net            = net,
 339         };
 340
 341         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
 342                         (int)hostname_len, hostname, rqstp->rq_vers,
 343                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 344
 345         mutex_lock(&nlm_host_mutex);
 346
 347         if (time_after_eq(jiffies, next_gc))
 348                 nlm_gc_hosts();
 349
 350         chain = &nlm_server_hosts[nlm_hash_address(ni.sap)];
 351         hlist_for_each_entry(host, pos, chain, h_hash) {
 352                 if (host->net != net)
 353                         continue;
 354                 if (!rpc_cmp_addr(nlm_addr(host), ni.sap))
 355                         continue;
 356
 357                 /* Same address. Share an NSM handle if we already have one */
 358                 if (nsm == NULL)
 359                         nsm = host->h_nsmhandle;
 360
 361                 if (host->h_proto != ni.protocol)
 362                         continue;
 363                 if (host->h_version != ni.version)
 364                         continue;
 365                 if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap))
 366                         continue;
 367
 368                 /* Move to head of hash chain. */
 369                 hlist_del(&host->h_hash);
 370                 hlist_add_head(&host->h_hash, chain);
 371
 372                 nlm_get_host(host);
 373                 dprintk("lockd: %s found host %s (%s)\n",
 374                         __func__, host->h_name, host->h_addrbuf);
 375                 goto out;
 376         }
 377
 378         host = nlm_alloc_host(&ni, nsm);
 379         if (unlikely(host == NULL))
 380                 goto out;
 381
 382         memcpy(nlm_srcaddr(host), src_sap, src_len);
 383         host->h_srcaddrlen = src_len;
 384         hlist_add_head(&host->h_hash, chain);
 385         nrhosts++;
 386
 387         dprintk("lockd: %s created host %s (%s)\n",
 388                 __func__, host->h_name, host->h_addrbuf);
 389
 390 out:
 391         mutex_unlock(&nlm_host_mutex);
 392         return host;
 393 }
 394
 395 /**
 396  * nlmsvc_release_host - release server nlm_host
 397  * @host: nlm_host to release
 398  *
 399  * Host is destroyed later in nlm_gc_host().
 400  */
 401 void nlmsvc_release_host(struct nlm_host *host)
 402 {
 403         if (host == NULL)
 404                 return;
 405
 406         dprintk("lockd: release server host %s\n", host->h_name);
 407
 408         BUG_ON(atomic_read(&host->h_count) < 0);
 409         BUG_ON(!host->h_server);
 410         atomic_dec(&host->h_count);
 411 }
 412
 413 /*
 414  * Create the NLM RPC client for an NLM peer
 415  */
 416 struct rpc_clnt *
 417 nlm_bind_host(struct nlm_host *host)
 418 {
 419         struct rpc_clnt *clnt;
 420
 421         dprintk("lockd: nlm_bind_host %s (%s)\n",
 422                         host->h_name, host->h_addrbuf);
 423
 424         /* Lock host handle */
 425         mutex_lock(&host->h_mutex);
 426
 427         /* If we've already created an RPC client, check whether
 428          * RPC rebind is required
 429          */
 430         if ((clnt = host->h_rpcclnt) != NULL) {
 431                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 432                         rpc_force_rebind(clnt);
 433                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 434                         dprintk("lockd: next rebind in %lu jiffies\n",
 435                                         host->h_nextrebind - jiffies);
 436                 }
 437         } else {
 438                 unsigned long increment = nlmsvc_timeout;
 439                 struct rpc_timeout timeparms = {
 440                         .to_initval     = increment,
 441                         .to_increment   = increment,
 442                         .to_maxval      = increment * 6UL,
 443                         .to_retries     = 5U,
 444                 };
 445                 struct rpc_create_args args = {
 446                         .net            = host->net,
 447                         .protocol       = host->h_proto,
 448                         .address        = nlm_addr(host),
 449                         .addrsize       = host->h_addrlen,
 450                         .timeout        = &timeparms,
 451                         .servername     = host->h_name,
 452                         .program        = &nlm_program,
 453                         .version        = host->h_version,
 454                         .authflavor     = RPC_AUTH_UNIX,
 455                         .flags          = (RPC_CLNT_CREATE_NOPING |
 456                                            RPC_CLNT_CREATE_AUTOBIND),
 457                 };
 458
 459                 /*
 460                  * lockd retries server side blocks automatically so we want
 461                  * those to be soft RPC calls. Client side calls need to be
 462                  * hard RPC tasks.
 463                  */
 464                 if (!host->h_server)
 465                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 466                 if (host->h_noresvport)
 467                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 468                 if (host->h_srcaddrlen)
 469                         args.saddress = nlm_srcaddr(host);
 470
 471                 clnt = rpc_create(&args);
 472                 if (!IS_ERR(clnt))
 473                         host->h_rpcclnt = clnt;
 474                 else {
 475                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 476                         clnt = NULL;
 477                 }
 478         }
 479
 480         mutex_unlock(&host->h_mutex);
 481         return clnt;
 482 }
 483
 484 /*
 485  * Force a portmap lookup of the remote lockd port
 486  */
 487 void
 488 nlm_rebind_host(struct nlm_host *host)
 489 {
 490         dprintk("lockd: rebind host %s\n", host->h_name);
 491         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 492                 rpc_force_rebind(host->h_rpcclnt);
 493                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 494         }
 495 }
 496
 497 /*
 498  * Increment NLM host count
 499  */
 500 struct nlm_host * nlm_get_host(struct nlm_host *host)
 501 {
 502         if (host) {
 503                 dprintk("lockd: get host %s\n", host->h_name);
 504                 atomic_inc(&host->h_count);
 505                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 506         }
 507         return host;
 508 }
 509
 510 static struct nlm_host *next_host_state(struct hlist_head *cache,
 511                                         struct nsm_handle *nsm,
 512                                         const struct nlm_reboot *info)
 513 {
 514         struct nlm_host *host;
 515         struct hlist_head *chain;
 516         struct hlist_node *pos;
 517
 518         mutex_lock(&nlm_host_mutex);
 519         for_each_host(host, pos, chain, cache) {
 520                 if (host->h_nsmhandle == nsm
 521                     && host->h_nsmstate != info->state) {
 522                         host->h_nsmstate = info->state;
 523                         host->h_state++;
 524
 525                         nlm_get_host(host);
 526                         mutex_unlock(&nlm_host_mutex);
 527                         return host;
 528                 }
 529         }
 530
 531         mutex_unlock(&nlm_host_mutex);
 532         return NULL;
 533 }
 534
 535 /**
 536  * nlm_host_rebooted - Release all resources held by rebooted host
 537  * @info: pointer to decoded results of NLM_SM_NOTIFY call
 538  *
 539  * We were notified that the specified host has rebooted.  Release
 540  * all resources held by that peer.
 541  */
 542 void nlm_host_rebooted(const struct nlm_reboot *info)
 543 {
 544         struct nsm_handle *nsm;
 545         struct nlm_host *host;
 546
 547         nsm = nsm_reboot_lookup(info);
 548         if (unlikely(nsm == NULL))
 549                 return;
 550
 551         /* Mark all hosts tied to this NSM state as having rebooted.
 552          * We run the loop repeatedly, because we drop the host table
 553          * lock for this.
 554          * To avoid processing a host several times, we match the nsmstate.
 555          */
 556         while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) {
 557                 nlmsvc_free_host_resources(host);
 558                 nlmsvc_release_host(host);
 559         }
 560         while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
 561                 nlmclnt_recovery(host);
 562                 nlmclnt_release_host(host);
 563         }
 564
 565         nsm_release(nsm);
 566 }
 567
 568 void
 569 nlm_shutdown_hosts_net(struct net *net)
 570 {
 571         struct hlist_head *chain;
 572         struct hlist_node *pos;
 573         struct nlm_host *host;
 574
 575         dprintk("lockd: shutting down host module\n");
 576         mutex_lock(&nlm_host_mutex);
 577
 578         /* First, make all hosts eligible for gc */
 579         dprintk("lockd: nuking all hosts...\n");
 580         for_each_host(host, pos, chain, nlm_server_hosts) {
 581                 if (net && host->net != net)
 582                         continue;
 583                 host->h_expires = jiffies - 1;
 584                 if (host->h_rpcclnt) {
 585                         rpc_shutdown_client(host->h_rpcclnt);
 586                         host->h_rpcclnt = NULL;
 587                 }
 588         }
 589
 590         /* Then, perform a garbage collection pass */
 591         nlm_gc_hosts();
 592         mutex_unlock(&nlm_host_mutex);
 593 }
 594
 595 /*
 596  * Shut down the hosts module.
 597  * Note that this routine is called only at server shutdown time.
 598  */
 599 void
 600 nlm_shutdown_hosts(void)
 601 {
 602         struct hlist_head *chain;
 603         struct hlist_node *pos;
 604         struct nlm_host *host;
 605
 606         nlm_shutdown_hosts_net(NULL);
 607
 608         /* complain if any hosts are left */
 609         if (nrhosts != 0) {
 610                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 611                 dprintk("lockd: %lu hosts left:\n", nrhosts);
 612                 for_each_host(host, pos, chain, nlm_server_hosts) {
 613                         dprintk("       %s (cnt %d use %d exp %ld net %p)\n",
 614                                 host->h_name, atomic_read(&host->h_count),
 615                                 host->h_inuse, host->h_expires, host->net);
 616                 }
 617         }
 618 }
 619
 620 /*
 621  * Garbage collect any unused NLM hosts.
 622  * This GC combines reference counting for async operations with
 623  * mark & sweep for resources held by remote clients.
 624  */
 625 static void
 626 nlm_gc_hosts(void)
 627 {
 628         struct hlist_head *chain;
 629         struct hlist_node *pos, *next;
 630         struct nlm_host *host;
 631
 632         dprintk("lockd: host garbage collection\n");
 633         for_each_host(host, pos, chain, nlm_server_hosts)
 634                 host->h_inuse = 0;
 635
 636         /* Mark all hosts that hold locks, blocks or shares */
 637         nlmsvc_mark_resources();
 638
 639         for_each_host_safe(host, pos, next, chain, nlm_server_hosts) {
 640                 if (atomic_read(&host->h_count) || host->h_inuse
 641                  || time_before(jiffies, host->h_expires)) {
 642                         dprintk("nlm_gc_hosts skipping %s "
 643                                 "(cnt %d use %d exp %ld)\n",
 644                                 host->h_name, atomic_read(&host->h_count),
 645                                 host->h_inuse, host->h_expires);
 646                         continue;
 647                 }
 648                 nlm_destroy_host_locked(host);
 649         }
 650
 651         next_gc = jiffies + NLM_HOST_COLLECT;
 652 }