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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/lockd/sm_inter.h>
  19 #include <linux/mutex.h>
  20
  21 #include <net/ipv6.h>
  22
  23 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  24 #define NLM_HOST_NRHASH         32
  25 #define NLM_HOST_REBIND         (60 * HZ)
  26 #define NLM_HOST_EXPIRE         (300 * HZ)
  27 #define NLM_HOST_COLLECT        (120 * HZ)
  28
  29 static struct hlist_head        nlm_hosts[NLM_HOST_NRHASH];
  30 static unsigned long            next_gc;
  31 static int                      nrhosts;
  32 static DEFINE_MUTEX(nlm_host_mutex);
  33
  34 static void                     nlm_gc_hosts(void);
  35
  36 struct nlm_lookup_host_info {
  37         const int               server;         /* search for server|client */
  38         const struct sockaddr   *sap;           /* address to search for */
  39         const size_t            salen;          /* it's length */
  40         const unsigned short    protocol;       /* transport to search for*/
  41         const u32               version;        /* NLM version to search for */
  42         const char              *hostname;      /* remote's hostname */
  43         const size_t            hostname_len;   /* it's length */
  44         const struct sockaddr   *src_sap;       /* our address (optional) */
  45         const size_t            src_len;        /* it's length */
  46         const int               noresvport;     /* use non-priv port */
  47 };
  48
  49 /*
  50  * Hash function must work well on big- and little-endian platforms
  51  */
  52 static unsigned int __nlm_hash32(const __be32 n)
  53 {
  54         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  55         return hash ^ (hash >> 8);
  56 }
  57
  58 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  59 {
  60         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  61         return __nlm_hash32(sin->sin_addr.s_addr);
  62 }
  63
  64 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  65 {
  66         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  67         const struct in6_addr addr = sin6->sin6_addr;
  68         return __nlm_hash32(addr.s6_addr32[0]) ^
  69                __nlm_hash32(addr.s6_addr32[1]) ^
  70                __nlm_hash32(addr.s6_addr32[2]) ^
  71                __nlm_hash32(addr.s6_addr32[3]);
  72 }
  73
  74 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  75 {
  76         unsigned int hash;
  77
  78         switch (sap->sa_family) {
  79         case AF_INET:
  80                 hash = __nlm_hash_addr4(sap);
  81                 break;
  82         case AF_INET6:
  83                 hash = __nlm_hash_addr6(sap);
  84                 break;
  85         default:
  86                 hash = 0;
  87         }
  88         return hash & (NLM_HOST_NRHASH - 1);
  89 }
  90
  91 static void nlm_clear_port(struct sockaddr *sap)
  92 {
  93         switch (sap->sa_family) {
  94         case AF_INET:
  95                 ((struct sockaddr_in *)sap)->sin_port = 0;
  96                 break;
  97         case AF_INET6:
  98                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
  99                 break;
 100         }
 101 }
 102
 103 /*
 104  * Common host lookup routine for server & client
 105  */
 106 static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
 107 {
 108         struct hlist_head *chain;
 109         struct hlist_node *pos;
 110         struct nlm_host *host;
 111         struct nsm_handle *nsm = NULL;
 112
 113         mutex_lock(&nlm_host_mutex);
 114
 115         if (time_after_eq(jiffies, next_gc))
 116                 nlm_gc_hosts();
 117
 118         /* We may keep several nlm_host objects for a peer, because each
 119          * nlm_host is identified by
 120          * (address, protocol, version, server/client)
 121          * We could probably simplify this a little by putting all those
 122          * different NLM rpc_clients into one single nlm_host object.
 123          * This would allow us to have one nlm_host per address.
 124          */
 125         chain = &nlm_hosts[nlm_hash_address(ni->sap)];
 126         hlist_for_each_entry(host, pos, chain, h_hash) {
 127                 if (!nlm_cmp_addr(nlm_addr(host), ni->sap))
 128                         continue;
 129
 130                 /* See if we have an NSM handle for this client */
 131                 if (!nsm)
 132                         nsm = host->h_nsmhandle;
 133
 134                 if (host->h_proto != ni->protocol)
 135                         continue;
 136                 if (host->h_version != ni->version)
 137                         continue;
 138                 if (host->h_server != ni->server)
 139                         continue;
 140                 if (ni->server &&
 141                     !nlm_cmp_addr(nlm_srcaddr(host), ni->src_sap))
 142                         continue;
 143
 144                 /* Move to head of hash chain. */
 145                 hlist_del(&host->h_hash);
 146                 hlist_add_head(&host->h_hash, chain);
 147
 148                 nlm_get_host(host);
 149                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
 150                                 host->h_name, host->h_addrbuf);
 151                 goto out;
 152         }
 153
 154         /*
 155          * The host wasn't in our hash table.  If we don't
 156          * have an NSM handle for it yet, create one.
 157          */
 158         if (nsm)
 159                 atomic_inc(&nsm->sm_count);
 160         else {
 161                 host = NULL;
 162                 nsm = nsm_find(ni->sap, ni->salen,
 163                                 ni->hostname, ni->hostname_len, 1);
 164                 if (!nsm) {
 165                         dprintk("lockd: nlm_lookup_host failed; "
 166                                 "no nsm handle\n");
 167                         goto out;
 168                 }
 169         }
 170
 171         host = kzalloc(sizeof(*host), GFP_KERNEL);
 172         if (!host) {
 173                 nsm_release(nsm);
 174                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
 175                 goto out;
 176         }
 177         host->h_name       = nsm->sm_name;
 178         host->h_addrbuf    = nsm->sm_addrbuf;
 179         memcpy(nlm_addr(host), ni->sap, ni->salen);
 180         host->h_addrlen = ni->salen;
 181         nlm_clear_port(nlm_addr(host));
 182         memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
 183         host->h_version    = ni->version;
 184         host->h_proto      = ni->protocol;
 185         host->h_rpcclnt    = NULL;
 186         mutex_init(&host->h_mutex);
 187         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 188         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 189         atomic_set(&host->h_count, 1);
 190         init_waitqueue_head(&host->h_gracewait);
 191         init_rwsem(&host->h_rwsem);
 192         host->h_state      = 0;                 /* pseudo NSM state */
 193         host->h_nsmstate   = 0;                 /* real NSM state */
 194         host->h_nsmhandle  = nsm;
 195         host->h_server     = ni->server;
 196         host->h_noresvport = ni->noresvport;
 197         hlist_add_head(&host->h_hash, chain);
 198         INIT_LIST_HEAD(&host->h_lockowners);
 199         spin_lock_init(&host->h_lock);
 200         INIT_LIST_HEAD(&host->h_granted);
 201         INIT_LIST_HEAD(&host->h_reclaim);
 202
 203         nrhosts++;
 204
 205         dprintk("lockd: nlm_lookup_host created host %s\n",
 206                         host->h_name);
 207
 208 out:
 209         mutex_unlock(&nlm_host_mutex);
 210         return host;
 211 }
 212
 213 /*
 214  * Destroy a host
 215  */
 216 static void
 217 nlm_destroy_host(struct nlm_host *host)
 218 {
 219         struct rpc_clnt *clnt;
 220
 221         BUG_ON(!list_empty(&host->h_lockowners));
 222         BUG_ON(atomic_read(&host->h_count));
 223
 224         nsm_unmonitor(host);
 225         nsm_release(host->h_nsmhandle);
 226
 227         clnt = host->h_rpcclnt;
 228         if (clnt != NULL)
 229                 rpc_shutdown_client(clnt);
 230         kfree(host);
 231 }
 232
 233 /**
 234  * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
 235  * @sap: network address of server
 236  * @salen: length of server address
 237  * @protocol: transport protocol to use
 238  * @version: NLM protocol version
 239  * @hostname: '\0'-terminated hostname of server
 240  * @noresvport: 1 if non-privileged port should be used
 241  *
 242  * Returns an nlm_host structure that matches the passed-in
 243  * [server address, transport protocol, NLM version, server hostname].
 244  * If one doesn't already exist in the host cache, a new handle is
 245  * created and returned.
 246  */
 247 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
 248                                      const size_t salen,
 249                                      const unsigned short protocol,
 250                                      const u32 version,
 251                                      const char *hostname,
 252                                      int noresvport)
 253 {
 254         const struct sockaddr source = {
 255                 .sa_family      = AF_UNSPEC,
 256         };
 257         struct nlm_lookup_host_info ni = {
 258                 .server         = 0,
 259                 .sap            = sap,
 260                 .salen          = salen,
 261                 .protocol       = protocol,
 262                 .version        = version,
 263                 .hostname       = hostname,
 264                 .hostname_len   = strlen(hostname),
 265                 .src_sap        = &source,
 266                 .src_len        = sizeof(source),
 267                 .noresvport     = noresvport,
 268         };
 269
 270         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
 271                         (hostname ? hostname : "<none>"), version,
 272                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
 273
 274         return nlm_lookup_host(&ni);
 275 }
 276
 277 /**
 278  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
 279  * @rqstp: incoming NLM request
 280  * @hostname: name of client host
 281  * @hostname_len: length of client hostname
 282  *
 283  * Returns an nlm_host structure that matches the [client address,
 284  * transport protocol, NLM version, client hostname] of the passed-in
 285  * NLM request.  If one doesn't already exist in the host cache, a
 286  * new handle is created and returned.
 287  *
 288  * Before possibly creating a new nlm_host, construct a sockaddr
 289  * for a specific source address in case the local system has
 290  * multiple network addresses.  The family of the address in
 291  * rq_daddr is guaranteed to be the same as the family of the
 292  * address in rq_addr, so it's safe to use the same family for
 293  * the source address.
 294  */
 295 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
 296                                     const char *hostname,
 297                                     const size_t hostname_len)
 298 {
 299         struct sockaddr_in sin = {
 300                 .sin_family     = AF_INET,
 301         };
 302         struct sockaddr_in6 sin6 = {
 303                 .sin6_family    = AF_INET6,
 304         };
 305         struct nlm_lookup_host_info ni = {
 306                 .server         = 1,
 307                 .sap            = svc_addr(rqstp),
 308                 .salen          = rqstp->rq_addrlen,
 309                 .protocol       = rqstp->rq_prot,
 310                 .version        = rqstp->rq_vers,
 311                 .hostname       = hostname,
 312                 .hostname_len   = hostname_len,
 313                 .src_len        = rqstp->rq_addrlen,
 314         };
 315
 316         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
 317                         (int)hostname_len, hostname, rqstp->rq_vers,
 318                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 319
 320         switch (ni.sap->sa_family) {
 321         case AF_INET:
 322                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
 323                 ni.src_sap = (struct sockaddr *)&sin;
 324                 break;
 325         case AF_INET6:
 326                 ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
 327                 ni.src_sap = (struct sockaddr *)&sin6;
 328                 break;
 329         default:
 330                 return NULL;
 331         }
 332
 333         return nlm_lookup_host(&ni);
 334 }
 335
 336 /*
 337  * Create the NLM RPC client for an NLM peer
 338  */
 339 struct rpc_clnt *
 340 nlm_bind_host(struct nlm_host *host)
 341 {
 342         struct rpc_clnt *clnt;
 343
 344         dprintk("lockd: nlm_bind_host %s (%s)\n",
 345                         host->h_name, host->h_addrbuf);
 346
 347         /* Lock host handle */
 348         mutex_lock(&host->h_mutex);
 349
 350         /* If we've already created an RPC client, check whether
 351          * RPC rebind is required
 352          */
 353         if ((clnt = host->h_rpcclnt) != NULL) {
 354                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 355                         rpc_force_rebind(clnt);
 356                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 357                         dprintk("lockd: next rebind in %lu jiffies\n",
 358                                         host->h_nextrebind - jiffies);
 359                 }
 360         } else {
 361                 unsigned long increment = nlmsvc_timeout;
 362                 struct rpc_timeout timeparms = {
 363                         .to_initval     = increment,
 364                         .to_increment   = increment,
 365                         .to_maxval      = increment * 6UL,
 366                         .to_retries     = 5U,
 367                 };
 368                 struct rpc_create_args args = {
 369                         .protocol       = host->h_proto,
 370                         .address        = nlm_addr(host),
 371                         .addrsize       = host->h_addrlen,
 372                         .saddress       = nlm_srcaddr(host),
 373                         .timeout        = &timeparms,
 374                         .servername     = host->h_name,
 375                         .program        = &nlm_program,
 376                         .version        = host->h_version,
 377                         .authflavor     = RPC_AUTH_UNIX,
 378                         .flags          = (RPC_CLNT_CREATE_NOPING |
 379                                            RPC_CLNT_CREATE_AUTOBIND),
 380                 };
 381
 382                 /*
 383                  * lockd retries server side blocks automatically so we want
 384                  * those to be soft RPC calls. Client side calls need to be
 385                  * hard RPC tasks.
 386                  */
 387                 if (!host->h_server)
 388                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 389                 if (host->h_noresvport)
 390                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 391
 392                 clnt = rpc_create(&args);
 393                 if (!IS_ERR(clnt))
 394                         host->h_rpcclnt = clnt;
 395                 else {
 396                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 397                         clnt = NULL;
 398                 }
 399         }
 400
 401         mutex_unlock(&host->h_mutex);
 402         return clnt;
 403 }
 404
 405 /*
 406  * Force a portmap lookup of the remote lockd port
 407  */
 408 void
 409 nlm_rebind_host(struct nlm_host *host)
 410 {
 411         dprintk("lockd: rebind host %s\n", host->h_name);
 412         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 413                 rpc_force_rebind(host->h_rpcclnt);
 414                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 415         }
 416 }
 417
 418 /*
 419  * Increment NLM host count
 420  */
 421 struct nlm_host * nlm_get_host(struct nlm_host *host)
 422 {
 423         if (host) {
 424                 dprintk("lockd: get host %s\n", host->h_name);
 425                 atomic_inc(&host->h_count);
 426                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 427         }
 428         return host;
 429 }
 430
 431 /*
 432  * Release NLM host after use
 433  */
 434 void nlm_release_host(struct nlm_host *host)
 435 {
 436         if (host != NULL) {
 437                 dprintk("lockd: release host %s\n", host->h_name);
 438                 BUG_ON(atomic_read(&host->h_count) < 0);
 439                 if (atomic_dec_and_test(&host->h_count)) {
 440                         BUG_ON(!list_empty(&host->h_lockowners));
 441                         BUG_ON(!list_empty(&host->h_granted));
 442                         BUG_ON(!list_empty(&host->h_reclaim));
 443                 }
 444         }
 445 }
 446
 447 /**
 448  * nlm_host_rebooted - Release all resources held by rebooted host
 449  * @info: pointer to decoded results of NLM_SM_NOTIFY call
 450  *
 451  * We were notified that the specified host has rebooted.  Release
 452  * all resources held by that peer.
 453  */
 454 void nlm_host_rebooted(const struct nlm_reboot *info)
 455 {
 456         struct hlist_head *chain;
 457         struct hlist_node *pos;
 458         struct nsm_handle *nsm;
 459         struct nlm_host *host;
 460
 461         nsm = nsm_reboot_lookup(info);
 462         if (unlikely(nsm == NULL))
 463                 return;
 464
 465         /* Mark all hosts tied to this NSM state as having rebooted.
 466          * We run the loop repeatedly, because we drop the host table
 467          * lock for this.
 468          * To avoid processing a host several times, we match the nsmstate.
 469          */
 470 again:  mutex_lock(&nlm_host_mutex);
 471         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 472                 hlist_for_each_entry(host, pos, chain, h_hash) {
 473                         if (host->h_nsmhandle == nsm
 474                          && host->h_nsmstate != info->state) {
 475                                 host->h_nsmstate = info->state;
 476                                 host->h_state++;
 477
 478                                 nlm_get_host(host);
 479                                 mutex_unlock(&nlm_host_mutex);
 480
 481                                 if (host->h_server) {
 482                                         /* We're server for this guy, just ditch
 483                                          * all the locks he held. */
 484                                         nlmsvc_free_host_resources(host);
 485                                 } else {
 486                                         /* He's the server, initiate lock recovery. */
 487                                         nlmclnt_recovery(host);
 488                                 }
 489
 490                                 nlm_release_host(host);
 491                                 goto again;
 492                         }
 493                 }
 494         }
 495
 496         mutex_unlock(&nlm_host_mutex);
 497 }
 498
 499 /*
 500  * Shut down the hosts module.
 501  * Note that this routine is called only at server shutdown time.
 502  */
 503 void
 504 nlm_shutdown_hosts(void)
 505 {
 506         struct hlist_head *chain;
 507         struct hlist_node *pos;
 508         struct nlm_host *host;
 509
 510         dprintk("lockd: shutting down host module\n");
 511         mutex_lock(&nlm_host_mutex);
 512
 513         /* First, make all hosts eligible for gc */
 514         dprintk("lockd: nuking all hosts...\n");
 515         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 516                 hlist_for_each_entry(host, pos, chain, h_hash) {
 517                         host->h_expires = jiffies - 1;
 518                         if (host->h_rpcclnt) {
 519                                 rpc_shutdown_client(host->h_rpcclnt);
 520                                 host->h_rpcclnt = NULL;
 521                         }
 522                 }
 523         }
 524
 525         /* Then, perform a garbage collection pass */
 526         nlm_gc_hosts();
 527         mutex_unlock(&nlm_host_mutex);
 528
 529         /* complain if any hosts are left */
 530         if (nrhosts) {
 531                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 532                 dprintk("lockd: %d hosts left:\n", nrhosts);
 533                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 534                         hlist_for_each_entry(host, pos, chain, h_hash) {
 535                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 536                                         host->h_name, atomic_read(&host->h_count),
 537                                         host->h_inuse, host->h_expires);
 538                         }
 539                 }
 540         }
 541 }
 542
 543 /*
 544  * Garbage collect any unused NLM hosts.
 545  * This GC combines reference counting for async operations with
 546  * mark & sweep for resources held by remote clients.
 547  */
 548 static void
 549 nlm_gc_hosts(void)
 550 {
 551         struct hlist_head *chain;
 552         struct hlist_node *pos, *next;
 553         struct nlm_host *host;
 554
 555         dprintk("lockd: host garbage collection\n");
 556         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 557                 hlist_for_each_entry(host, pos, chain, h_hash)
 558                         host->h_inuse = 0;
 559         }
 560
 561         /* Mark all hosts that hold locks, blocks or shares */
 562         nlmsvc_mark_resources();
 563
 564         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 565                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 566                         if (atomic_read(&host->h_count) || host->h_inuse
 567                          || time_before(jiffies, host->h_expires)) {
 568                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 569                                         host->h_name, atomic_read(&host->h_count),
 570                                         host->h_inuse, host->h_expires);
 571                                 continue;
 572                         }
 573                         dprintk("lockd: delete host %s\n", host->h_name);
 574                         hlist_del_init(&host->h_hash);
 575
 576                         nlm_destroy_host(host);
 577                         nrhosts--;
 578                 }
 579         }
 580
 581         next_gc = jiffies + NLM_HOST_COLLECT;
 582 }