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   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_hosts[NLM_HOST_NRHASH];
  29 static unsigned long            next_gc;
  30 static int                      nrhosts;
  31 static DEFINE_MUTEX(nlm_host_mutex);
  32
  33 static void                     nlm_gc_hosts(void);
  34
  35 struct nlm_lookup_host_info {
  36         const int               server;         /* search for server|client */
  37         const struct sockaddr   *sap;           /* address to search for */
  38         const size_t            salen;          /* it's length */
  39         const unsigned short    protocol;       /* transport to search for*/
  40         const u32               version;        /* NLM version to search for */
  41         const char              *hostname;      /* remote's hostname */
  42         const size_t            hostname_len;   /* it's length */
  43         const struct sockaddr   *src_sap;       /* our address (optional) */
  44         const size_t            src_len;        /* it's length */
  45         const int               noresvport;     /* use non-priv port */
  46 };
  47
  48 /*
  49  * Hash function must work well on big- and little-endian platforms
  50  */
  51 static unsigned int __nlm_hash32(const __be32 n)
  52 {
  53         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  54         return hash ^ (hash >> 8);
  55 }
  56
  57 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  58 {
  59         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  60         return __nlm_hash32(sin->sin_addr.s_addr);
  61 }
  62
  63 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  64 {
  65         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  66         const struct in6_addr addr = sin6->sin6_addr;
  67         return __nlm_hash32(addr.s6_addr32[0]) ^
  68                __nlm_hash32(addr.s6_addr32[1]) ^
  69                __nlm_hash32(addr.s6_addr32[2]) ^
  70                __nlm_hash32(addr.s6_addr32[3]);
  71 }
  72
  73 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  74 {
  75         unsigned int hash;
  76
  77         switch (sap->sa_family) {
  78         case AF_INET:
  79                 hash = __nlm_hash_addr4(sap);
  80                 break;
  81         case AF_INET6:
  82                 hash = __nlm_hash_addr6(sap);
  83                 break;
  84         default:
  85                 hash = 0;
  86         }
  87         return hash & (NLM_HOST_NRHASH - 1);
  88 }
  89
  90 static void nlm_clear_port(struct sockaddr *sap)
  91 {
  92         switch (sap->sa_family) {
  93         case AF_INET:
  94                 ((struct sockaddr_in *)sap)->sin_port = 0;
  95                 break;
  96         case AF_INET6:
  97                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
  98                 break;
  99         }
 100 }
 101
 102 /*
 103  * Common host lookup routine for server & client
 104  */
 105 static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
 106 {
 107         struct hlist_head *chain;
 108         struct hlist_node *pos;
 109         struct nlm_host *host;
 110         struct nsm_handle *nsm = NULL;
 111
 112         mutex_lock(&nlm_host_mutex);
 113
 114         if (time_after_eq(jiffies, next_gc))
 115                 nlm_gc_hosts();
 116
 117         /* We may keep several nlm_host objects for a peer, because each
 118          * nlm_host is identified by
 119          * (address, protocol, version, server/client)
 120          * We could probably simplify this a little by putting all those
 121          * different NLM rpc_clients into one single nlm_host object.
 122          * This would allow us to have one nlm_host per address.
 123          */
 124         chain = &nlm_hosts[nlm_hash_address(ni->sap)];
 125         hlist_for_each_entry(host, pos, chain, h_hash) {
 126                 if (!nlm_cmp_addr(nlm_addr(host), ni->sap))
 127                         continue;
 128
 129                 /* See if we have an NSM handle for this client */
 130                 if (!nsm)
 131                         nsm = host->h_nsmhandle;
 132
 133                 if (host->h_proto != ni->protocol)
 134                         continue;
 135                 if (host->h_version != ni->version)
 136                         continue;
 137                 if (host->h_server != ni->server)
 138                         continue;
 139                 if (ni->server &&
 140                     !nlm_cmp_addr(nlm_srcaddr(host), ni->src_sap))
 141                         continue;
 142
 143                 /* Move to head of hash chain. */
 144                 hlist_del(&host->h_hash);
 145                 hlist_add_head(&host->h_hash, chain);
 146
 147                 nlm_get_host(host);
 148                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
 149                                 host->h_name, host->h_addrbuf);
 150                 goto out;
 151         }
 152
 153         /*
 154          * The host wasn't in our hash table.  If we don't
 155          * have an NSM handle for it yet, create one.
 156          */
 157         if (nsm)
 158                 atomic_inc(&nsm->sm_count);
 159         else {
 160                 host = NULL;
 161                 nsm = nsm_get_handle(ni->sap, ni->salen,
 162                                         ni->hostname, ni->hostname_len);
 163                 if (!nsm) {
 164                         dprintk("lockd: nlm_lookup_host failed; "
 165                                 "no nsm handle\n");
 166                         goto out;
 167                 }
 168         }
 169
 170         host = kzalloc(sizeof(*host), GFP_KERNEL);
 171         if (!host) {
 172                 nsm_release(nsm);
 173                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
 174                 goto out;
 175         }
 176         host->h_name       = nsm->sm_name;
 177         host->h_addrbuf    = nsm->sm_addrbuf;
 178         memcpy(nlm_addr(host), ni->sap, ni->salen);
 179         host->h_addrlen = ni->salen;
 180         nlm_clear_port(nlm_addr(host));
 181         memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
 182         host->h_version    = ni->version;
 183         host->h_proto      = ni->protocol;
 184         host->h_rpcclnt    = NULL;
 185         mutex_init(&host->h_mutex);
 186         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 187         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 188         atomic_set(&host->h_count, 1);
 189         init_waitqueue_head(&host->h_gracewait);
 190         init_rwsem(&host->h_rwsem);
 191         host->h_state      = 0;                 /* pseudo NSM state */
 192         host->h_nsmstate   = 0;                 /* real NSM state */
 193         host->h_nsmhandle  = nsm;
 194         host->h_server     = ni->server;
 195         host->h_noresvport = ni->noresvport;
 196         hlist_add_head(&host->h_hash, chain);
 197         INIT_LIST_HEAD(&host->h_lockowners);
 198         spin_lock_init(&host->h_lock);
 199         INIT_LIST_HEAD(&host->h_granted);
 200         INIT_LIST_HEAD(&host->h_reclaim);
 201
 202         nrhosts++;
 203
 204         dprintk("lockd: nlm_lookup_host created host %s\n",
 205                         host->h_name);
 206
 207 out:
 208         mutex_unlock(&nlm_host_mutex);
 209         return host;
 210 }
 211
 212 /*
 213  * Destroy a host
 214  */
 215 static void
 216 nlm_destroy_host(struct nlm_host *host)
 217 {
 218         struct rpc_clnt *clnt;
 219
 220         BUG_ON(!list_empty(&host->h_lockowners));
 221         BUG_ON(atomic_read(&host->h_count));
 222
 223         nsm_unmonitor(host);
 224         nsm_release(host->h_nsmhandle);
 225
 226         clnt = host->h_rpcclnt;
 227         if (clnt != NULL)
 228                 rpc_shutdown_client(clnt);
 229         kfree(host);
 230 }
 231
 232 /**
 233  * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
 234  * @sap: network address of server
 235  * @salen: length of server address
 236  * @protocol: transport protocol to use
 237  * @version: NLM protocol version
 238  * @hostname: '\0'-terminated hostname of server
 239  * @noresvport: 1 if non-privileged port should be used
 240  *
 241  * Returns an nlm_host structure that matches the passed-in
 242  * [server address, transport protocol, NLM version, server hostname].
 243  * If one doesn't already exist in the host cache, a new handle is
 244  * created and returned.
 245  */
 246 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
 247                                      const size_t salen,
 248                                      const unsigned short protocol,
 249                                      const u32 version,
 250                                      const char *hostname,
 251                                      int noresvport)
 252 {
 253         const struct sockaddr source = {
 254                 .sa_family      = AF_UNSPEC,
 255         };
 256         struct nlm_lookup_host_info ni = {
 257                 .server         = 0,
 258                 .sap            = sap,
 259                 .salen          = salen,
 260                 .protocol       = protocol,
 261                 .version        = version,
 262                 .hostname       = hostname,
 263                 .hostname_len   = strlen(hostname),
 264                 .src_sap        = &source,
 265                 .src_len        = sizeof(source),
 266                 .noresvport     = noresvport,
 267         };
 268
 269         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
 270                         (hostname ? hostname : "<none>"), version,
 271                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
 272
 273         return nlm_lookup_host(&ni);
 274 }
 275
 276 /**
 277  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
 278  * @rqstp: incoming NLM request
 279  * @hostname: name of client host
 280  * @hostname_len: length of client hostname
 281  *
 282  * Returns an nlm_host structure that matches the [client address,
 283  * transport protocol, NLM version, client hostname] of the passed-in
 284  * NLM request.  If one doesn't already exist in the host cache, a
 285  * new handle is created and returned.
 286  *
 287  * Before possibly creating a new nlm_host, construct a sockaddr
 288  * for a specific source address in case the local system has
 289  * multiple network addresses.  The family of the address in
 290  * rq_daddr is guaranteed to be the same as the family of the
 291  * address in rq_addr, so it's safe to use the same family for
 292  * the source address.
 293  */
 294 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
 295                                     const char *hostname,
 296                                     const size_t hostname_len)
 297 {
 298         struct sockaddr_in sin = {
 299                 .sin_family     = AF_INET,
 300         };
 301         struct sockaddr_in6 sin6 = {
 302                 .sin6_family    = AF_INET6,
 303         };
 304         struct nlm_lookup_host_info ni = {
 305                 .server         = 1,
 306                 .sap            = svc_addr(rqstp),
 307                 .salen          = rqstp->rq_addrlen,
 308                 .protocol       = rqstp->rq_prot,
 309                 .version        = rqstp->rq_vers,
 310                 .hostname       = hostname,
 311                 .hostname_len   = hostname_len,
 312                 .src_len        = rqstp->rq_addrlen,
 313         };
 314
 315         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
 316                         (int)hostname_len, hostname, rqstp->rq_vers,
 317                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 318
 319         switch (ni.sap->sa_family) {
 320         case AF_INET:
 321                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
 322                 ni.src_sap = (struct sockaddr *)&sin;
 323                 break;
 324         case AF_INET6:
 325                 ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
 326                 ni.src_sap = (struct sockaddr *)&sin6;
 327                 break;
 328         default:
 329                 return NULL;
 330         }
 331
 332         return nlm_lookup_host(&ni);
 333 }
 334
 335 /*
 336  * Create the NLM RPC client for an NLM peer
 337  */
 338 struct rpc_clnt *
 339 nlm_bind_host(struct nlm_host *host)
 340 {
 341         struct rpc_clnt *clnt;
 342
 343         dprintk("lockd: nlm_bind_host %s (%s)\n",
 344                         host->h_name, host->h_addrbuf);
 345
 346         /* Lock host handle */
 347         mutex_lock(&host->h_mutex);
 348
 349         /* If we've already created an RPC client, check whether
 350          * RPC rebind is required
 351          */
 352         if ((clnt = host->h_rpcclnt) != NULL) {
 353                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 354                         rpc_force_rebind(clnt);
 355                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 356                         dprintk("lockd: next rebind in %lu jiffies\n",
 357                                         host->h_nextrebind - jiffies);
 358                 }
 359         } else {
 360                 unsigned long increment = nlmsvc_timeout;
 361                 struct rpc_timeout timeparms = {
 362                         .to_initval     = increment,
 363                         .to_increment   = increment,
 364                         .to_maxval      = increment * 6UL,
 365                         .to_retries     = 5U,
 366                 };
 367                 struct rpc_create_args args = {
 368                         .protocol       = host->h_proto,
 369                         .address        = nlm_addr(host),
 370                         .addrsize       = host->h_addrlen,
 371                         .saddress       = nlm_srcaddr(host),
 372                         .timeout        = &timeparms,
 373                         .servername     = host->h_name,
 374                         .program        = &nlm_program,
 375                         .version        = host->h_version,
 376                         .authflavor     = RPC_AUTH_UNIX,
 377                         .flags          = (RPC_CLNT_CREATE_NOPING |
 378                                            RPC_CLNT_CREATE_AUTOBIND),
 379                 };
 380
 381                 /*
 382                  * lockd retries server side blocks automatically so we want
 383                  * those to be soft RPC calls. Client side calls need to be
 384                  * hard RPC tasks.
 385                  */
 386                 if (!host->h_server)
 387                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 388                 if (host->h_noresvport)
 389                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 390
 391                 clnt = rpc_create(&args);
 392                 if (!IS_ERR(clnt))
 393                         host->h_rpcclnt = clnt;
 394                 else {
 395                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 396                         clnt = NULL;
 397                 }
 398         }
 399
 400         mutex_unlock(&host->h_mutex);
 401         return clnt;
 402 }
 403
 404 /*
 405  * Force a portmap lookup of the remote lockd port
 406  */
 407 void
 408 nlm_rebind_host(struct nlm_host *host)
 409 {
 410         dprintk("lockd: rebind host %s\n", host->h_name);
 411         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 412                 rpc_force_rebind(host->h_rpcclnt);
 413                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 414         }
 415 }
 416
 417 /*
 418  * Increment NLM host count
 419  */
 420 struct nlm_host * nlm_get_host(struct nlm_host *host)
 421 {
 422         if (host) {
 423                 dprintk("lockd: get host %s\n", host->h_name);
 424                 atomic_inc(&host->h_count);
 425                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 426         }
 427         return host;
 428 }
 429
 430 /*
 431  * Release NLM host after use
 432  */
 433 void nlm_release_host(struct nlm_host *host)
 434 {
 435         if (host != NULL) {
 436                 dprintk("lockd: release host %s\n", host->h_name);
 437                 BUG_ON(atomic_read(&host->h_count) < 0);
 438                 if (atomic_dec_and_test(&host->h_count)) {
 439                         BUG_ON(!list_empty(&host->h_lockowners));
 440                         BUG_ON(!list_empty(&host->h_granted));
 441                         BUG_ON(!list_empty(&host->h_reclaim));
 442                 }
 443         }
 444 }
 445
 446 /**
 447  * nlm_host_rebooted - Release all resources held by rebooted host
 448  * @info: pointer to decoded results of NLM_SM_NOTIFY call
 449  *
 450  * We were notified that the specified host has rebooted.  Release
 451  * all resources held by that peer.
 452  */
 453 void nlm_host_rebooted(const struct nlm_reboot *info)
 454 {
 455         struct hlist_head *chain;
 456         struct hlist_node *pos;
 457         struct nsm_handle *nsm;
 458         struct nlm_host *host;
 459
 460         nsm = nsm_reboot_lookup(info);
 461         if (unlikely(nsm == NULL))
 462                 return;
 463
 464         /* Mark all hosts tied to this NSM state as having rebooted.
 465          * We run the loop repeatedly, because we drop the host table
 466          * lock for this.
 467          * To avoid processing a host several times, we match the nsmstate.
 468          */
 469 again:  mutex_lock(&nlm_host_mutex);
 470         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 471                 hlist_for_each_entry(host, pos, chain, h_hash) {
 472                         if (host->h_nsmhandle == nsm
 473                          && host->h_nsmstate != info->state) {
 474                                 host->h_nsmstate = info->state;
 475                                 host->h_state++;
 476
 477                                 nlm_get_host(host);
 478                                 mutex_unlock(&nlm_host_mutex);
 479
 480                                 if (host->h_server) {
 481                                         /* We're server for this guy, just ditch
 482                                          * all the locks he held. */
 483                                         nlmsvc_free_host_resources(host);
 484                                 } else {
 485                                         /* He's the server, initiate lock recovery. */
 486                                         nlmclnt_recovery(host);
 487                                 }
 488
 489                                 nlm_release_host(host);
 490                                 goto again;
 491                         }
 492                 }
 493         }
 494
 495         mutex_unlock(&nlm_host_mutex);
 496 }
 497
 498 /*
 499  * Shut down the hosts module.
 500  * Note that this routine is called only at server shutdown time.
 501  */
 502 void
 503 nlm_shutdown_hosts(void)
 504 {
 505         struct hlist_head *chain;
 506         struct hlist_node *pos;
 507         struct nlm_host *host;
 508
 509         dprintk("lockd: shutting down host module\n");
 510         mutex_lock(&nlm_host_mutex);
 511
 512         /* First, make all hosts eligible for gc */
 513         dprintk("lockd: nuking all hosts...\n");
 514         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 515                 hlist_for_each_entry(host, pos, chain, h_hash) {
 516                         host->h_expires = jiffies - 1;
 517                         if (host->h_rpcclnt) {
 518                                 rpc_shutdown_client(host->h_rpcclnt);
 519                                 host->h_rpcclnt = NULL;
 520                         }
 521                 }
 522         }
 523
 524         /* Then, perform a garbage collection pass */
 525         nlm_gc_hosts();
 526         mutex_unlock(&nlm_host_mutex);
 527
 528         /* complain if any hosts are left */
 529         if (nrhosts) {
 530                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 531                 dprintk("lockd: %d hosts left:\n", nrhosts);
 532                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 533                         hlist_for_each_entry(host, pos, chain, h_hash) {
 534                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 535                                         host->h_name, atomic_read(&host->h_count),
 536                                         host->h_inuse, host->h_expires);
 537                         }
 538                 }
 539         }
 540 }
 541
 542 /*
 543  * Garbage collect any unused NLM hosts.
 544  * This GC combines reference counting for async operations with
 545  * mark & sweep for resources held by remote clients.
 546  */
 547 static void
 548 nlm_gc_hosts(void)
 549 {
 550         struct hlist_head *chain;
 551         struct hlist_node *pos, *next;
 552         struct nlm_host *host;
 553
 554         dprintk("lockd: host garbage collection\n");
 555         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 556                 hlist_for_each_entry(host, pos, chain, h_hash)
 557                         host->h_inuse = 0;
 558         }
 559
 560         /* Mark all hosts that hold locks, blocks or shares */
 561         nlmsvc_mark_resources();
 562
 563         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 564                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 565                         if (atomic_read(&host->h_count) || host->h_inuse
 566                          || time_before(jiffies, host->h_expires)) {
 567                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 568                                         host->h_name, atomic_read(&host->h_count),
 569                                         host->h_inuse, host->h_expires);
 570                                 continue;
 571                         }
 572                         dprintk("lockd: delete host %s\n", host->h_name);
 573                         hlist_del_init(&host->h_hash);
 574
 575                         nlm_destroy_host(host);
 576                         nrhosts--;
 577                 }
 578         }
 579
 580         next_gc = jiffies + NLM_HOST_COLLECT;
 581 }