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