fs/lockd/host.c

   1 /*
   2  * linux/fs/lockd/host.c
   3  *
   4  * Management for NLM peer hosts. The nlm_host struct is shared
   5  * between client and server implementation. The only reason to
   6  * do so is to reduce code bloat.
   7  *
   8  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/slab.h>
  13 #include <linux/in.h>
  14 #include <linux/in6.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/sunrpc/svc.h>
  17 #include <linux/lockd/lockd.h>
  18 #include <linux/mutex.h>
  19
  20 #include <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
  30 #define for_each_host(host, pos, chain, table) \
  31         for ((chain) = (table); \
  32              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
  33                 hlist_for_each_entry((host), (pos), (chain), h_hash)
  34
  35 #define for_each_host_safe(host, pos, next, chain, table) \
  36         for ((chain) = (table); \
  37              (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \
  38                 hlist_for_each_entry_safe((host), (pos), (next), \
  39                                                 (chain), h_hash)
  40
  41 static unsigned long            next_gc;
  42 static int                      nrhosts;
  43 static DEFINE_MUTEX(nlm_host_mutex);
  44
  45 static void                     nlm_gc_hosts(void);
  46
  47 struct nlm_lookup_host_info {
  48         const int               server;         /* search for server|client */
  49         const struct sockaddr   *sap;           /* address to search for */
  50         const size_t            salen;          /* it's length */
  51         const unsigned short    protocol;       /* transport to search for*/
  52         const u32               version;        /* NLM version to search for */
  53         const char              *hostname;      /* remote's hostname */
  54         const size_t            hostname_len;   /* it's length */
  55         const struct sockaddr   *src_sap;       /* our address (optional) */
  56         const size_t            src_len;        /* it's length */
  57         const int               noresvport;     /* use non-priv port */
  58 };
  59
  60 /*
  61  * Hash function must work well on big- and little-endian platforms
  62  */
  63 static unsigned int __nlm_hash32(const __be32 n)
  64 {
  65         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  66         return hash ^ (hash >> 8);
  67 }
  68
  69 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  70 {
  71         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  72         return __nlm_hash32(sin->sin_addr.s_addr);
  73 }
  74
  75 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  76 {
  77         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  78         const struct in6_addr addr = sin6->sin6_addr;
  79         return __nlm_hash32(addr.s6_addr32[0]) ^
  80                __nlm_hash32(addr.s6_addr32[1]) ^
  81                __nlm_hash32(addr.s6_addr32[2]) ^
  82                __nlm_hash32(addr.s6_addr32[3]);
  83 }
  84
  85 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  86 {
  87         unsigned int hash;
  88
  89         switch (sap->sa_family) {
  90         case AF_INET:
  91                 hash = __nlm_hash_addr4(sap);
  92                 break;
  93         case AF_INET6:
  94                 hash = __nlm_hash_addr6(sap);
  95                 break;
  96         default:
  97                 hash = 0;
  98         }
  99         return hash & (NLM_HOST_NRHASH - 1);
 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 (!rpc_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 && ni->src_len != 0 &&
 140                     !rpc_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         rpc_set_port(nlm_addr(host), 0);
 181         memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
 182         host->h_srcaddrlen = 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         struct nlm_lookup_host_info ni = {
 255                 .server         = 0,
 256                 .sap            = sap,
 257                 .salen          = salen,
 258                 .protocol       = protocol,
 259                 .version        = version,
 260                 .hostname       = hostname,
 261                 .hostname_len   = strlen(hostname),
 262                 .noresvport     = noresvport,
 263         };
 264
 265         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
 266                         (hostname ? hostname : "<none>"), version,
 267                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
 268
 269         return nlm_lookup_host(&ni);
 270 }
 271
 272 /**
 273  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
 274  * @rqstp: incoming NLM request
 275  * @hostname: name of client host
 276  * @hostname_len: length of client hostname
 277  *
 278  * Returns an nlm_host structure that matches the [client address,
 279  * transport protocol, NLM version, client hostname] of the passed-in
 280  * NLM request.  If one doesn't already exist in the host cache, a
 281  * new handle is created and returned.
 282  *
 283  * Before possibly creating a new nlm_host, construct a sockaddr
 284  * for a specific source address in case the local system has
 285  * multiple network addresses.  The family of the address in
 286  * rq_daddr is guaranteed to be the same as the family of the
 287  * address in rq_addr, so it's safe to use the same family for
 288  * the source address.
 289  */
 290 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
 291                                     const char *hostname,
 292                                     const size_t hostname_len)
 293 {
 294         struct sockaddr_in sin = {
 295                 .sin_family     = AF_INET,
 296         };
 297         struct sockaddr_in6 sin6 = {
 298                 .sin6_family    = AF_INET6,
 299         };
 300         struct nlm_lookup_host_info ni = {
 301                 .server         = 1,
 302                 .sap            = svc_addr(rqstp),
 303                 .salen          = rqstp->rq_addrlen,
 304                 .protocol       = rqstp->rq_prot,
 305                 .version        = rqstp->rq_vers,
 306                 .hostname       = hostname,
 307                 .hostname_len   = hostname_len,
 308                 .src_len        = rqstp->rq_addrlen,
 309         };
 310
 311         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
 312                         (int)hostname_len, hostname, rqstp->rq_vers,
 313                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 314
 315         switch (ni.sap->sa_family) {
 316         case AF_INET:
 317                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
 318                 ni.src_sap = (struct sockaddr *)&sin;
 319                 break;
 320         case AF_INET6:
 321                 ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
 322                 ni.src_sap = (struct sockaddr *)&sin6;
 323                 break;
 324         default:
 325                 return NULL;
 326         }
 327
 328         return nlm_lookup_host(&ni);
 329 }
 330
 331 /*
 332  * Create the NLM RPC client for an NLM peer
 333  */
 334 struct rpc_clnt *
 335 nlm_bind_host(struct nlm_host *host)
 336 {
 337         struct rpc_clnt *clnt;
 338
 339         dprintk("lockd: nlm_bind_host %s (%s)\n",
 340                         host->h_name, host->h_addrbuf);
 341
 342         /* Lock host handle */
 343         mutex_lock(&host->h_mutex);
 344
 345         /* If we've already created an RPC client, check whether
 346          * RPC rebind is required
 347          */
 348         if ((clnt = host->h_rpcclnt) != NULL) {
 349                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 350                         rpc_force_rebind(clnt);
 351                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 352                         dprintk("lockd: next rebind in %lu jiffies\n",
 353                                         host->h_nextrebind - jiffies);
 354                 }
 355         } else {
 356                 unsigned long increment = nlmsvc_timeout;
 357                 struct rpc_timeout timeparms = {
 358                         .to_initval     = increment,
 359                         .to_increment   = increment,
 360                         .to_maxval      = increment * 6UL,
 361                         .to_retries     = 5U,
 362                 };
 363                 struct rpc_create_args args = {
 364                         .net            = &init_net,
 365                         .protocol       = host->h_proto,
 366                         .address        = nlm_addr(host),
 367                         .addrsize       = host->h_addrlen,
 368                         .timeout        = &timeparms,
 369                         .servername     = host->h_name,
 370                         .program        = &nlm_program,
 371                         .version        = host->h_version,
 372                         .authflavor     = RPC_AUTH_UNIX,
 373                         .flags          = (RPC_CLNT_CREATE_NOPING |
 374                                            RPC_CLNT_CREATE_AUTOBIND),
 375                 };
 376
 377                 /*
 378                  * lockd retries server side blocks automatically so we want
 379                  * those to be soft RPC calls. Client side calls need to be
 380                  * hard RPC tasks.
 381                  */
 382                 if (!host->h_server)
 383                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 384                 if (host->h_noresvport)
 385                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 386                 if (host->h_srcaddrlen)
 387                         args.saddress = nlm_srcaddr(host);
 388
 389                 clnt = rpc_create(&args);
 390                 if (!IS_ERR(clnt))
 391                         host->h_rpcclnt = clnt;
 392                 else {
 393                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 394                         clnt = NULL;
 395                 }
 396         }
 397
 398         mutex_unlock(&host->h_mutex);
 399         return clnt;
 400 }
 401
 402 /*
 403  * Force a portmap lookup of the remote lockd port
 404  */
 405 void
 406 nlm_rebind_host(struct nlm_host *host)
 407 {
 408         dprintk("lockd: rebind host %s\n", host->h_name);
 409         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 410                 rpc_force_rebind(host->h_rpcclnt);
 411                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 412         }
 413 }
 414
 415 /*
 416  * Increment NLM host count
 417  */
 418 struct nlm_host * nlm_get_host(struct nlm_host *host)
 419 {
 420         if (host) {
 421                 dprintk("lockd: get host %s\n", host->h_name);
 422                 atomic_inc(&host->h_count);
 423                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 424         }
 425         return host;
 426 }
 427
 428 /*
 429  * Release NLM host after use
 430  */
 431 void nlm_release_host(struct nlm_host *host)
 432 {
 433         if (host != NULL) {
 434                 dprintk("lockd: release host %s\n", host->h_name);
 435                 BUG_ON(atomic_read(&host->h_count) < 0);
 436                 if (atomic_dec_and_test(&host->h_count)) {
 437                         BUG_ON(!list_empty(&host->h_lockowners));
 438                         BUG_ON(!list_empty(&host->h_granted));
 439                         BUG_ON(!list_empty(&host->h_reclaim));
 440                 }
 441         }
 442 }
 443
 444 /**
 445  * nlm_host_rebooted - Release all resources held by rebooted host
 446  * @info: pointer to decoded results of NLM_SM_NOTIFY call
 447  *
 448  * We were notified that the specified host has rebooted.  Release
 449  * all resources held by that peer.
 450  */
 451 void nlm_host_rebooted(const struct nlm_reboot *info)
 452 {
 453         struct hlist_head *chain;
 454         struct hlist_node *pos;
 455         struct nsm_handle *nsm;
 456         struct nlm_host *host;
 457
 458         nsm = nsm_reboot_lookup(info);
 459         if (unlikely(nsm == NULL))
 460                 return;
 461
 462         /* Mark all hosts tied to this NSM state as having rebooted.
 463          * We run the loop repeatedly, because we drop the host table
 464          * lock for this.
 465          * To avoid processing a host several times, we match the nsmstate.
 466          */
 467 again:  mutex_lock(&nlm_host_mutex);
 468         for_each_host(host, pos, chain, nlm_hosts) {
 469                 if (host->h_nsmhandle == nsm
 470                  && host->h_nsmstate != info->state) {
 471                         host->h_nsmstate = info->state;
 472                         host->h_state++;
 473
 474                         nlm_get_host(host);
 475                         mutex_unlock(&nlm_host_mutex);
 476
 477                         if (host->h_server) {
 478                                 /* We're server for this guy, just ditch
 479                                  * all the locks he held. */
 480                                 nlmsvc_free_host_resources(host);
 481                         } else {
 482                                 /* He's the server, initiate lock recovery. */
 483                                 nlmclnt_recovery(host);
 484                         }
 485
 486                         nlm_release_host(host);
 487                         goto again;
 488                 }
 489         }
 490         mutex_unlock(&nlm_host_mutex);
 491         nsm_release(nsm);
 492 }
 493
 494 /*
 495  * Shut down the hosts module.
 496  * Note that this routine is called only at server shutdown time.
 497  */
 498 void
 499 nlm_shutdown_hosts(void)
 500 {
 501         struct hlist_head *chain;
 502         struct hlist_node *pos;
 503         struct nlm_host *host;
 504
 505         dprintk("lockd: shutting down host module\n");
 506         mutex_lock(&nlm_host_mutex);
 507
 508         /* First, make all hosts eligible for gc */
 509         dprintk("lockd: nuking all hosts...\n");
 510         for_each_host(host, pos, chain, nlm_hosts) {
 511                 host->h_expires = jiffies - 1;
 512                 if (host->h_rpcclnt) {
 513                         rpc_shutdown_client(host->h_rpcclnt);
 514                         host->h_rpcclnt = NULL;
 515                 }
 516         }
 517
 518         /* Then, perform a garbage collection pass */
 519         nlm_gc_hosts();
 520         mutex_unlock(&nlm_host_mutex);
 521
 522         /* complain if any hosts are left */
 523         if (nrhosts) {
 524                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 525                 dprintk("lockd: %d hosts left:\n", nrhosts);
 526                 for_each_host(host, pos, chain, nlm_hosts) {
 527                         dprintk("       %s (cnt %d use %d exp %ld)\n",
 528                                 host->h_name, atomic_read(&host->h_count),
 529                                 host->h_inuse, host->h_expires);
 530                 }
 531         }
 532 }
 533
 534 /*
 535  * Garbage collect any unused NLM hosts.
 536  * This GC combines reference counting for async operations with
 537  * mark & sweep for resources held by remote clients.
 538  */
 539 static void
 540 nlm_gc_hosts(void)
 541 {
 542         struct hlist_head *chain;
 543         struct hlist_node *pos, *next;
 544         struct nlm_host *host;
 545
 546         dprintk("lockd: host garbage collection\n");
 547         for_each_host(host, pos, chain, nlm_hosts)
 548                 host->h_inuse = 0;
 549
 550         /* Mark all hosts that hold locks, blocks or shares */
 551         nlmsvc_mark_resources();
 552
 553         for_each_host_safe(host, pos, next, chain, nlm_hosts) {
 554                 if (atomic_read(&host->h_count) || host->h_inuse
 555                  || time_before(jiffies, host->h_expires)) {
 556                         dprintk("nlm_gc_hosts skipping %s "
 557                                 "(cnt %d use %d exp %ld)\n",
 558                                 host->h_name, atomic_read(&host->h_count),
 559                                 host->h_inuse, host->h_expires);
 560                         continue;
 561                 }
 562                 dprintk("lockd: delete host %s\n", host->h_name);
 563                 hlist_del_init(&host->h_hash);
 564
 565                 nlm_destroy_host(host);
 566                 nrhosts--;
 567         }
 568
 569         next_gc = jiffies + NLM_HOST_COLLECT;
 570 }