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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
  35 static void                     nlm_gc_hosts(void);
  36 static struct nsm_handle *      __nsm_find(const struct sockaddr_in *,
  37                                         const char *, unsigned int, int);
  38 static struct nsm_handle *      nsm_find(const struct sockaddr_in *sin,
  39                                          const char *hostname,
  40                                          unsigned int hostname_len);
  41
  42 /*
  43  * Hash function must work well on big- and little-endian platforms
  44  */
  45 static unsigned int __nlm_hash32(const __be32 n)
  46 {
  47         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  48         return hash ^ (hash >> 8);
  49 }
  50
  51 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  52 {
  53         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  54         return __nlm_hash32(sin->sin_addr.s_addr);
  55 }
  56
  57 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  58 {
  59         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  60         const struct in6_addr addr = sin6->sin6_addr;
  61         return __nlm_hash32(addr.s6_addr32[0]) ^
  62                __nlm_hash32(addr.s6_addr32[1]) ^
  63                __nlm_hash32(addr.s6_addr32[2]) ^
  64                __nlm_hash32(addr.s6_addr32[3]);
  65 }
  66
  67 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  68 {
  69         unsigned int hash;
  70
  71         switch (sap->sa_family) {
  72         case AF_INET:
  73                 hash = __nlm_hash_addr4(sap);
  74                 break;
  75         case AF_INET6:
  76                 hash = __nlm_hash_addr6(sap);
  77                 break;
  78         default:
  79                 hash = 0;
  80         }
  81         return hash & (NLM_HOST_NRHASH - 1);
  82 }
  83
  84 static void nlm_clear_port(struct sockaddr *sap)
  85 {
  86         switch (sap->sa_family) {
  87         case AF_INET:
  88                 ((struct sockaddr_in *)sap)->sin_port = 0;
  89                 break;
  90         case AF_INET6:
  91                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
  92                 break;
  93         }
  94 }
  95
  96 static void nlm_display_address(const struct sockaddr *sap,
  97                                 char *buf, const size_t len)
  98 {
  99         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 100         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 101
 102         switch (sap->sa_family) {
 103         case AF_UNSPEC:
 104                 snprintf(buf, len, "unspecified");
 105                 break;
 106         case AF_INET:
 107                 snprintf(buf, len, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
 108                 break;
 109         case AF_INET6:
 110                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 111                         snprintf(buf, len, NIPQUAD_FMT,
 112                                  NIPQUAD(sin6->sin6_addr.s6_addr32[3]));
 113                 else
 114                         snprintf(buf, len, NIP6_FMT, NIP6(sin6->sin6_addr));
 115                 break;
 116         default:
 117                 snprintf(buf, len, "unsupported address family");
 118                 break;
 119         }
 120 }
 121
 122 /*
 123  * Common host lookup routine for server & client
 124  */
 125 static struct nlm_host *nlm_lookup_host(int server,
 126                                         const struct sockaddr_in *sin,
 127                                         int proto, u32 version,
 128                                         const char *hostname,
 129                                         unsigned int hostname_len,
 130                                         const struct sockaddr_in *ssin)
 131 {
 132         struct hlist_head *chain;
 133         struct hlist_node *pos;
 134         struct nlm_host *host;
 135         struct nsm_handle *nsm = NULL;
 136
 137         dprintk("lockd: nlm_lookup_host(proto=%d, vers=%u,"
 138                         " my role is %s, hostname=%.*s)\n",
 139                         proto, version, server ? "server" : "client",
 140                         hostname_len, hostname ? hostname : "<none>");
 141
 142         mutex_lock(&nlm_host_mutex);
 143
 144         if (time_after_eq(jiffies, next_gc))
 145                 nlm_gc_hosts();
 146
 147         /* We may keep several nlm_host objects for a peer, because each
 148          * nlm_host is identified by
 149          * (address, protocol, version, server/client)
 150          * We could probably simplify this a little by putting all those
 151          * different NLM rpc_clients into one single nlm_host object.
 152          * This would allow us to have one nlm_host per address.
 153          */
 154         chain = &nlm_hosts[nlm_hash_address((struct sockaddr *)sin)];
 155         hlist_for_each_entry(host, pos, chain, h_hash) {
 156                 if (!nlm_cmp_addr(nlm_addr(host), (struct sockaddr *)sin))
 157                         continue;
 158
 159                 /* See if we have an NSM handle for this client */
 160                 if (!nsm)
 161                         nsm = host->h_nsmhandle;
 162
 163                 if (host->h_proto != proto)
 164                         continue;
 165                 if (host->h_version != version)
 166                         continue;
 167                 if (host->h_server != server)
 168                         continue;
 169                 if (!nlm_cmp_addr(nlm_srcaddr(host), (struct sockaddr *)ssin))
 170                         continue;
 171
 172                 /* Move to head of hash chain. */
 173                 hlist_del(&host->h_hash);
 174                 hlist_add_head(&host->h_hash, chain);
 175
 176                 nlm_get_host(host);
 177                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
 178                                 host->h_name, host->h_addrbuf);
 179                 goto out;
 180         }
 181
 182         /*
 183          * The host wasn't in our hash table.  If we don't
 184          * have an NSM handle for it yet, create one.
 185          */
 186         if (nsm)
 187                 atomic_inc(&nsm->sm_count);
 188         else {
 189                 host = NULL;
 190                 nsm = nsm_find(sin, hostname, hostname_len);
 191                 if (!nsm) {
 192                         dprintk("lockd: nlm_lookup_host failed; "
 193                                 "no nsm handle\n");
 194                         goto out;
 195                 }
 196         }
 197
 198         host = kzalloc(sizeof(*host), GFP_KERNEL);
 199         if (!host) {
 200                 nsm_release(nsm);
 201                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
 202                 goto out;
 203         }
 204         host->h_name       = nsm->sm_name;
 205         memcpy(nlm_addr(host), sin, sizeof(*sin));
 206         host->h_addrlen = sizeof(*sin);
 207         nlm_clear_port(nlm_addr(host));
 208         memcpy(nlm_srcaddr(host), ssin, sizeof(*ssin));
 209         host->h_version    = version;
 210         host->h_proto      = proto;
 211         host->h_rpcclnt    = NULL;
 212         mutex_init(&host->h_mutex);
 213         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 214         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 215         atomic_set(&host->h_count, 1);
 216         init_waitqueue_head(&host->h_gracewait);
 217         init_rwsem(&host->h_rwsem);
 218         host->h_state      = 0;                 /* pseudo NSM state */
 219         host->h_nsmstate   = 0;                 /* real NSM state */
 220         host->h_nsmhandle  = nsm;
 221         host->h_server     = server;
 222         hlist_add_head(&host->h_hash, chain);
 223         INIT_LIST_HEAD(&host->h_lockowners);
 224         spin_lock_init(&host->h_lock);
 225         INIT_LIST_HEAD(&host->h_granted);
 226         INIT_LIST_HEAD(&host->h_reclaim);
 227
 228         nrhosts++;
 229
 230         nlm_display_address((struct sockaddr *)&host->h_addr,
 231                                 host->h_addrbuf, sizeof(host->h_addrbuf));
 232         nlm_display_address((struct sockaddr *)&host->h_srcaddr,
 233                                 host->h_srcaddrbuf, sizeof(host->h_srcaddrbuf));
 234
 235         dprintk("lockd: nlm_lookup_host created host %s\n",
 236                         host->h_name);
 237
 238 out:
 239         mutex_unlock(&nlm_host_mutex);
 240         return host;
 241 }
 242
 243 /*
 244  * Destroy a host
 245  */
 246 static void
 247 nlm_destroy_host(struct nlm_host *host)
 248 {
 249         struct rpc_clnt *clnt;
 250
 251         BUG_ON(!list_empty(&host->h_lockowners));
 252         BUG_ON(atomic_read(&host->h_count));
 253
 254         /*
 255          * Release NSM handle and unmonitor host.
 256          */
 257         nsm_unmonitor(host);
 258
 259         clnt = host->h_rpcclnt;
 260         if (clnt != NULL)
 261                 rpc_shutdown_client(clnt);
 262         kfree(host);
 263 }
 264
 265 /*
 266  * Find an NLM server handle in the cache. If there is none, create it.
 267  */
 268 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr_in *sin,
 269                                      int proto, u32 version,
 270                                      const char *hostname,
 271                                      unsigned int hostname_len)
 272 {
 273         const struct sockaddr_in source = {
 274                 .sin_family     = AF_UNSPEC,
 275         };
 276
 277         return nlm_lookup_host(0, sin, proto, version,
 278                                hostname, hostname_len, &source);
 279 }
 280
 281 /*
 282  * Find an NLM client handle in the cache. If there is none, create it.
 283  */
 284 struct nlm_host *
 285 nlmsvc_lookup_host(struct svc_rqst *rqstp,
 286                         const char *hostname, unsigned int hostname_len)
 287 {
 288         const struct sockaddr_in source = {
 289                 .sin_family     = AF_INET,
 290                 .sin_addr       = rqstp->rq_daddr.addr,
 291         };
 292
 293         return nlm_lookup_host(1, svc_addr_in(rqstp),
 294                                rqstp->rq_prot, rqstp->rq_vers,
 295                                hostname, hostname_len, &source);
 296 }
 297
 298 /*
 299  * Create the NLM RPC client for an NLM peer
 300  */
 301 struct rpc_clnt *
 302 nlm_bind_host(struct nlm_host *host)
 303 {
 304         struct rpc_clnt *clnt;
 305
 306         dprintk("lockd: nlm_bind_host %s (%s), my addr=%s\n",
 307                         host->h_name, host->h_addrbuf, host->h_srcaddrbuf);
 308
 309         /* Lock host handle */
 310         mutex_lock(&host->h_mutex);
 311
 312         /* If we've already created an RPC client, check whether
 313          * RPC rebind is required
 314          */
 315         if ((clnt = host->h_rpcclnt) != NULL) {
 316                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 317                         rpc_force_rebind(clnt);
 318                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 319                         dprintk("lockd: next rebind in %lu jiffies\n",
 320                                         host->h_nextrebind - jiffies);
 321                 }
 322         } else {
 323                 unsigned long increment = nlmsvc_timeout;
 324                 struct rpc_timeout timeparms = {
 325                         .to_initval     = increment,
 326                         .to_increment   = increment,
 327                         .to_maxval      = increment * 6UL,
 328                         .to_retries     = 5U,
 329                 };
 330                 struct rpc_create_args args = {
 331                         .protocol       = host->h_proto,
 332                         .address        = nlm_addr(host),
 333                         .addrsize       = host->h_addrlen,
 334                         .saddress       = nlm_srcaddr(host),
 335                         .timeout        = &timeparms,
 336                         .servername     = host->h_name,
 337                         .program        = &nlm_program,
 338                         .version        = host->h_version,
 339                         .authflavor     = RPC_AUTH_UNIX,
 340                         .flags          = (RPC_CLNT_CREATE_NOPING |
 341                                            RPC_CLNT_CREATE_AUTOBIND),
 342                 };
 343
 344                 /*
 345                  * lockd retries server side blocks automatically so we want
 346                  * those to be soft RPC calls. Client side calls need to be
 347                  * hard RPC tasks.
 348                  */
 349                 if (!host->h_server)
 350                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 351
 352                 clnt = rpc_create(&args);
 353                 if (!IS_ERR(clnt))
 354                         host->h_rpcclnt = clnt;
 355                 else {
 356                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 357                         clnt = NULL;
 358                 }
 359         }
 360
 361         mutex_unlock(&host->h_mutex);
 362         return clnt;
 363 }
 364
 365 /*
 366  * Force a portmap lookup of the remote lockd port
 367  */
 368 void
 369 nlm_rebind_host(struct nlm_host *host)
 370 {
 371         dprintk("lockd: rebind host %s\n", host->h_name);
 372         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 373                 rpc_force_rebind(host->h_rpcclnt);
 374                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 375         }
 376 }
 377
 378 /*
 379  * Increment NLM host count
 380  */
 381 struct nlm_host * nlm_get_host(struct nlm_host *host)
 382 {
 383         if (host) {
 384                 dprintk("lockd: get host %s\n", host->h_name);
 385                 atomic_inc(&host->h_count);
 386                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 387         }
 388         return host;
 389 }
 390
 391 /*
 392  * Release NLM host after use
 393  */
 394 void nlm_release_host(struct nlm_host *host)
 395 {
 396         if (host != NULL) {
 397                 dprintk("lockd: release host %s\n", host->h_name);
 398                 BUG_ON(atomic_read(&host->h_count) < 0);
 399                 if (atomic_dec_and_test(&host->h_count)) {
 400                         BUG_ON(!list_empty(&host->h_lockowners));
 401                         BUG_ON(!list_empty(&host->h_granted));
 402                         BUG_ON(!list_empty(&host->h_reclaim));
 403                 }
 404         }
 405 }
 406
 407 /*
 408  * We were notified that the host indicated by address &sin
 409  * has rebooted.
 410  * Release all resources held by that peer.
 411  */
 412 void nlm_host_rebooted(const struct sockaddr_in *sin,
 413                                 const char *hostname,
 414                                 unsigned int hostname_len,
 415                                 u32 new_state)
 416 {
 417         struct hlist_head *chain;
 418         struct hlist_node *pos;
 419         struct nsm_handle *nsm;
 420         struct nlm_host *host;
 421
 422         /* Find the NSM handle for this peer */
 423         nsm = __nsm_find(sin, hostname, hostname_len, 0);
 424         if (nsm == NULL) {
 425                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 426                                 hostname_len, hostname);
 427                 return;
 428         }
 429
 430         dprintk("lockd: nlm_host_rebooted(%.*s, %s)\n",
 431                         hostname_len, hostname, nsm->sm_addrbuf);
 432
 433         /* When reclaiming locks on this peer, make sure that
 434          * we set up a new notification */
 435         nsm->sm_monitored = 0;
 436
 437         /* Mark all hosts tied to this NSM state as having rebooted.
 438          * We run the loop repeatedly, because we drop the host table
 439          * lock for this.
 440          * To avoid processing a host several times, we match the nsmstate.
 441          */
 442 again:  mutex_lock(&nlm_host_mutex);
 443         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 444                 hlist_for_each_entry(host, pos, chain, h_hash) {
 445                         if (host->h_nsmhandle == nsm
 446                          && host->h_nsmstate != new_state) {
 447                                 host->h_nsmstate = new_state;
 448                                 host->h_state++;
 449
 450                                 nlm_get_host(host);
 451                                 mutex_unlock(&nlm_host_mutex);
 452
 453                                 if (host->h_server) {
 454                                         /* We're server for this guy, just ditch
 455                                          * all the locks he held. */
 456                                         nlmsvc_free_host_resources(host);
 457                                 } else {
 458                                         /* He's the server, initiate lock recovery. */
 459                                         nlmclnt_recovery(host);
 460                                 }
 461
 462                                 nlm_release_host(host);
 463                                 goto again;
 464                         }
 465                 }
 466         }
 467
 468         mutex_unlock(&nlm_host_mutex);
 469 }
 470
 471 /*
 472  * Shut down the hosts module.
 473  * Note that this routine is called only at server shutdown time.
 474  */
 475 void
 476 nlm_shutdown_hosts(void)
 477 {
 478         struct hlist_head *chain;
 479         struct hlist_node *pos;
 480         struct nlm_host *host;
 481
 482         dprintk("lockd: shutting down host module\n");
 483         mutex_lock(&nlm_host_mutex);
 484
 485         /* First, make all hosts eligible for gc */
 486         dprintk("lockd: nuking all hosts...\n");
 487         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 488                 hlist_for_each_entry(host, pos, chain, h_hash) {
 489                         host->h_expires = jiffies - 1;
 490                         if (host->h_rpcclnt) {
 491                                 rpc_shutdown_client(host->h_rpcclnt);
 492                                 host->h_rpcclnt = NULL;
 493                         }
 494                 }
 495         }
 496
 497         /* Then, perform a garbage collection pass */
 498         nlm_gc_hosts();
 499         mutex_unlock(&nlm_host_mutex);
 500
 501         /* complain if any hosts are left */
 502         if (nrhosts) {
 503                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 504                 dprintk("lockd: %d hosts left:\n", nrhosts);
 505                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 506                         hlist_for_each_entry(host, pos, chain, h_hash) {
 507                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 508                                         host->h_name, atomic_read(&host->h_count),
 509                                         host->h_inuse, host->h_expires);
 510                         }
 511                 }
 512         }
 513 }
 514
 515 /*
 516  * Garbage collect any unused NLM hosts.
 517  * This GC combines reference counting for async operations with
 518  * mark & sweep for resources held by remote clients.
 519  */
 520 static void
 521 nlm_gc_hosts(void)
 522 {
 523         struct hlist_head *chain;
 524         struct hlist_node *pos, *next;
 525         struct nlm_host *host;
 526
 527         dprintk("lockd: host garbage collection\n");
 528         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 529                 hlist_for_each_entry(host, pos, chain, h_hash)
 530                         host->h_inuse = 0;
 531         }
 532
 533         /* Mark all hosts that hold locks, blocks or shares */
 534         nlmsvc_mark_resources();
 535
 536         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 537                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 538                         if (atomic_read(&host->h_count) || host->h_inuse
 539                          || time_before(jiffies, host->h_expires)) {
 540                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 541                                         host->h_name, atomic_read(&host->h_count),
 542                                         host->h_inuse, host->h_expires);
 543                                 continue;
 544                         }
 545                         dprintk("lockd: delete host %s\n", host->h_name);
 546                         hlist_del_init(&host->h_hash);
 547
 548                         nlm_destroy_host(host);
 549                         nrhosts--;
 550                 }
 551         }
 552
 553         next_gc = jiffies + NLM_HOST_COLLECT;
 554 }
 555
 556
 557 /*
 558  * Manage NSM handles
 559  */
 560 static LIST_HEAD(nsm_handles);
 561 static DEFINE_SPINLOCK(nsm_lock);
 562
 563 static struct nsm_handle *
 564 __nsm_find(const struct sockaddr_in *sin,
 565                 const char *hostname, unsigned int hostname_len,
 566                 int create)
 567 {
 568         struct nsm_handle *nsm = NULL;
 569         struct nsm_handle *pos;
 570
 571         if (!sin)
 572                 return NULL;
 573
 574         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 575                 if (printk_ratelimit()) {
 576                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 577                                             "in NFS lock request\n",
 578                                 hostname_len, hostname);
 579                 }
 580                 return NULL;
 581         }
 582
 583 retry:
 584         spin_lock(&nsm_lock);
 585         list_for_each_entry(pos, &nsm_handles, sm_link) {
 586
 587                 if (hostname && nsm_use_hostnames) {
 588                         if (strlen(pos->sm_name) != hostname_len
 589                          || memcmp(pos->sm_name, hostname, hostname_len))
 590                                 continue;
 591                 } else if (!nlm_cmp_addr(nsm_addr(pos), (struct sockaddr *)sin))
 592                         continue;
 593                 atomic_inc(&pos->sm_count);
 594                 kfree(nsm);
 595                 nsm = pos;
 596                 goto found;
 597         }
 598         if (nsm) {
 599                 list_add(&nsm->sm_link, &nsm_handles);
 600                 goto found;
 601         }
 602         spin_unlock(&nsm_lock);
 603
 604         if (!create)
 605                 return NULL;
 606
 607         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
 608         if (nsm == NULL)
 609                 return NULL;
 610
 611         memcpy(nsm_addr(nsm), sin, sizeof(*sin));
 612         nsm->sm_addrlen = sizeof(*sin);
 613         nsm->sm_name = (char *) (nsm + 1);
 614         memcpy(nsm->sm_name, hostname, hostname_len);
 615         nsm->sm_name[hostname_len] = '\0';
 616         nlm_display_address((struct sockaddr *)&nsm->sm_addr,
 617                                 nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
 618         atomic_set(&nsm->sm_count, 1);
 619         goto retry;
 620
 621 found:
 622         spin_unlock(&nsm_lock);
 623         return nsm;
 624 }
 625
 626 static struct nsm_handle *
 627 nsm_find(const struct sockaddr_in *sin, const char *hostname,
 628          unsigned int hostname_len)
 629 {
 630         return __nsm_find(sin, hostname, hostname_len, 1);
 631 }
 632
 633 /*
 634  * Release an NSM handle
 635  */
 636 void
 637 nsm_release(struct nsm_handle *nsm)
 638 {
 639         if (!nsm)
 640                 return;
 641         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 642                 list_del(&nsm->sm_link);
 643                 spin_unlock(&nsm_lock);
 644                 kfree(nsm);
 645         }
 646 }