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/addr.h> 17#include <linux/sunrpc/svc.h> 18#include <linux/lockd/lockd.h> 19#include <linux/mutex.h> 20 21#include <linux/sunrpc/svc_xprt.h> 22 23#include <net/ipv6.h> 24 25#include "netns.h" 26 27#define NLMDBG_FACILITY NLMDBG_HOSTCACHE 28#define NLM_HOST_NRHASH 32 29#define NLM_HOST_REBIND (60 * HZ) 30#define NLM_HOST_EXPIRE (300 * HZ) 31#define NLM_HOST_COLLECT (120 * HZ) 32 33static struct hlist_head nlm_server_hosts[NLM_HOST_NRHASH]; 34static struct hlist_head nlm_client_hosts[NLM_HOST_NRHASH]; 35 36#define for_each_host(host, chain, table) \ 37 for ((chain) = (table); \ 38 (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \ 39 hlist_for_each_entry((host), (chain), h_hash) 40 41#define for_each_host_safe(host, next, chain, table) \ 42 for ((chain) = (table); \ 43 (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \ 44 hlist_for_each_entry_safe((host), (next), \ 45 (chain), h_hash) 46 47static unsigned long nrhosts; 48static DEFINE_MUTEX(nlm_host_mutex); 49 50static void nlm_gc_hosts(struct net *net); 51 52struct nlm_lookup_host_info { 53 const int server; /* search for server|client */ 54 const struct sockaddr *sap; /* address to search for */ 55 const size_t salen; /* it's length */ 56 const unsigned short protocol; /* transport to search for*/ 57 const u32 version; /* NLM version to search for */ 58 const char *hostname; /* remote's hostname */ 59 const size_t hostname_len; /* it's length */ 60 const int noresvport; /* use non-priv port */ 61 struct net *net; /* network namespace to bind */ 62}; 63 64/* 65 * Hash function must work well on big- and little-endian platforms 66 */ 67static unsigned int __nlm_hash32(const __be32 n) 68{ 69 unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16); 70 return hash ^ (hash >> 8); 71} 72 73static unsigned int __nlm_hash_addr4(const struct sockaddr *sap) 74{ 75 const struct sockaddr_in *sin = (struct sockaddr_in *)sap; 76 return __nlm_hash32(sin->sin_addr.s_addr); 77} 78 79static unsigned int __nlm_hash_addr6(const struct sockaddr *sap) 80{ 81 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap; 82 const struct in6_addr addr = sin6->sin6_addr; 83 return __nlm_hash32(addr.s6_addr32[0]) ^ 84 __nlm_hash32(addr.s6_addr32[1]) ^ 85 __nlm_hash32(addr.s6_addr32[2]) ^ 86 __nlm_hash32(addr.s6_addr32[3]); 87} 88 89static unsigned int nlm_hash_address(const struct sockaddr *sap) 90{ 91 unsigned int hash; 92 93 switch (sap->sa_family) { 94 case AF_INET: 95 hash = __nlm_hash_addr4(sap); 96 break; 97 case AF_INET6: 98 hash = __nlm_hash_addr6(sap); 99 break; 100 default: 101 hash = 0; 102 } 103 return hash & (NLM_HOST_NRHASH - 1); 104} 105 106/* 107 * Allocate and initialize an nlm_host. Common to both client and server. 108 */ 109static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni, 110 struct nsm_handle *nsm) 111{ 112 struct nlm_host *host = NULL; 113 unsigned long now = jiffies; 114 115 if (nsm != NULL) 116 atomic_inc(&nsm->sm_count); 117 else { 118 host = NULL; 119 nsm = nsm_get_handle(ni->net, ni->sap, ni->salen, 120 ni->hostname, ni->hostname_len); 121 if (unlikely(nsm == NULL)) { 122 dprintk("lockd: %s failed; no nsm handle\n", 123 __func__); 124 goto out; 125 } 126 } 127 128 host = kmalloc(sizeof(*host), GFP_KERNEL); 129 if (unlikely(host == NULL)) { 130 dprintk("lockd: %s failed; no memory\n", __func__); 131 nsm_release(nsm); 132 goto out; 133 } 134 135 memcpy(nlm_addr(host), ni->sap, ni->salen); 136 host->h_addrlen = ni->salen; 137 rpc_set_port(nlm_addr(host), 0); 138 host->h_srcaddrlen = 0; 139 140 host->h_rpcclnt = NULL; 141 host->h_name = nsm->sm_name; 142 host->h_version = ni->version; 143 host->h_proto = ni->protocol; 144 host->h_reclaiming = 0; 145 host->h_server = ni->server; 146 host->h_noresvport = ni->noresvport; 147 host->h_inuse = 0; 148 init_waitqueue_head(&host->h_gracewait); 149 init_rwsem(&host->h_rwsem); 150 host->h_state = 0; 151 host->h_nsmstate = 0; 152 host->h_pidcount = 0; 153 atomic_set(&host->h_count, 1); 154 mutex_init(&host->h_mutex); 155 host->h_nextrebind = now + NLM_HOST_REBIND; 156 host->h_expires = now + NLM_HOST_EXPIRE; 157 INIT_LIST_HEAD(&host->h_lockowners); 158 spin_lock_init(&host->h_lock); 159 INIT_LIST_HEAD(&host->h_granted); 160 INIT_LIST_HEAD(&host->h_reclaim); 161 host->h_nsmhandle = nsm; 162 host->h_addrbuf = nsm->sm_addrbuf; 163 host->net = ni->net; 164 strlcpy(host->nodename, utsname()->nodename, sizeof(host->nodename)); 165 166out: 167 return host; 168} 169 170/* 171 * Destroy an nlm_host and free associated resources 172 * 173 * Caller must hold nlm_host_mutex. 174 */ 175static void nlm_destroy_host_locked(struct nlm_host *host) 176{ 177 struct rpc_clnt *clnt; 178 struct lockd_net *ln = net_generic(host->net, lockd_net_id); 179 180 dprintk("lockd: destroy host %s\n", host->h_name); 181 182 hlist_del_init(&host->h_hash); 183 184 nsm_unmonitor(host); 185 nsm_release(host->h_nsmhandle); 186 187 clnt = host->h_rpcclnt; 188 if (clnt != NULL) 189 rpc_shutdown_client(clnt); 190 kfree(host); 191 192 ln->nrhosts--; 193 nrhosts--; 194} 195 196/** 197 * nlmclnt_lookup_host - Find an NLM host handle matching a remote server 198 * @sap: network address of server 199 * @salen: length of server address 200 * @protocol: transport protocol to use 201 * @version: NLM protocol version 202 * @hostname: '\0'-terminated hostname of server 203 * @noresvport: 1 if non-privileged port should be used 204 * 205 * Returns an nlm_host structure that matches the passed-in 206 * [server address, transport protocol, NLM version, server hostname]. 207 * If one doesn't already exist in the host cache, a new handle is 208 * created and returned. 209 */ 210struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap, 211 const size_t salen, 212 const unsigned short protocol, 213 const u32 version, 214 const char *hostname, 215 int noresvport, 216 struct net *net) 217{ 218 struct nlm_lookup_host_info ni = { 219 .server = 0, 220 .sap = sap, 221 .salen = salen, 222 .protocol = protocol, 223 .version = version, 224 .hostname = hostname, 225 .hostname_len = strlen(hostname), 226 .noresvport = noresvport, 227 .net = net, 228 }; 229 struct hlist_head *chain; 230 struct nlm_host *host; 231 struct nsm_handle *nsm = NULL; 232 struct lockd_net *ln = net_generic(net, lockd_net_id); 233 234 dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__, 235 (hostname ? hostname : "<none>"), version, 236 (protocol == IPPROTO_UDP ? "udp" : "tcp")); 237 238 mutex_lock(&nlm_host_mutex); 239 240 chain = &nlm_client_hosts[nlm_hash_address(sap)]; 241 hlist_for_each_entry(host, chain, h_hash) { 242 if (host->net != net) 243 continue; 244 if (!rpc_cmp_addr(nlm_addr(host), sap)) 245 continue; 246 247 /* Same address. Share an NSM handle if we already have one */ 248 if (nsm == NULL) 249 nsm = host->h_nsmhandle; 250 251 if (host->h_proto != protocol) 252 continue; 253 if (host->h_version != version) 254 continue; 255 256 nlm_get_host(host); 257 dprintk("lockd: %s found host %s (%s)\n", __func__, 258 host->h_name, host->h_addrbuf); 259 goto out; 260 } 261 262 host = nlm_alloc_host(&ni, nsm); 263 if (unlikely(host == NULL)) 264 goto out; 265 266 hlist_add_head(&host->h_hash, chain); 267 ln->nrhosts++; 268 nrhosts++; 269 270 dprintk("lockd: %s created host %s (%s)\n", __func__, 271 host->h_name, host->h_addrbuf); 272 273out: 274 mutex_unlock(&nlm_host_mutex); 275 return host; 276} 277 278/** 279 * nlmclnt_release_host - release client nlm_host 280 * @host: nlm_host to release 281 * 282 */ 283void nlmclnt_release_host(struct nlm_host *host) 284{ 285 if (host == NULL) 286 return; 287 288 dprintk("lockd: release client host %s\n", host->h_name); 289 290 WARN_ON_ONCE(host->h_server); 291 292 if (atomic_dec_and_test(&host->h_count)) { 293 WARN_ON_ONCE(!list_empty(&host->h_lockowners)); 294 WARN_ON_ONCE(!list_empty(&host->h_granted)); 295 WARN_ON_ONCE(!list_empty(&host->h_reclaim)); 296 297 mutex_lock(&nlm_host_mutex); 298 nlm_destroy_host_locked(host); 299 mutex_unlock(&nlm_host_mutex); 300 } 301} 302 303/** 304 * nlmsvc_lookup_host - Find an NLM host handle matching a remote client 305 * @rqstp: incoming NLM request 306 * @hostname: name of client host 307 * @hostname_len: length of client hostname 308 * 309 * Returns an nlm_host structure that matches the [client address, 310 * transport protocol, NLM version, client hostname] of the passed-in 311 * NLM request. If one doesn't already exist in the host cache, a 312 * new handle is created and returned. 313 * 314 * Before possibly creating a new nlm_host, construct a sockaddr 315 * for a specific source address in case the local system has 316 * multiple network addresses. The family of the address in 317 * rq_daddr is guaranteed to be the same as the family of the 318 * address in rq_addr, so it's safe to use the same family for 319 * the source address. 320 */ 321struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp, 322 const char *hostname, 323 const size_t hostname_len) 324{ 325 struct hlist_head *chain; 326 struct nlm_host *host = NULL; 327 struct nsm_handle *nsm = NULL; 328 struct sockaddr *src_sap = svc_daddr(rqstp); 329 size_t src_len = rqstp->rq_daddrlen; 330 struct net *net = SVC_NET(rqstp); 331 struct nlm_lookup_host_info ni = { 332 .server = 1, 333 .sap = svc_addr(rqstp), 334 .salen = rqstp->rq_addrlen, 335 .protocol = rqstp->rq_prot, 336 .version = rqstp->rq_vers, 337 .hostname = hostname, 338 .hostname_len = hostname_len, 339 .net = net, 340 }; 341 struct lockd_net *ln = net_generic(net, lockd_net_id); 342 343 dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__, 344 (int)hostname_len, hostname, rqstp->rq_vers, 345 (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp")); 346 347 mutex_lock(&nlm_host_mutex); 348 349 if (time_after_eq(jiffies, ln->next_gc)) 350 nlm_gc_hosts(net); 351 352 chain = &nlm_server_hosts[nlm_hash_address(ni.sap)]; 353 hlist_for_each_entry(host, chain, h_hash) { 354 if (host->net != net) 355 continue; 356 if (!rpc_cmp_addr(nlm_addr(host), ni.sap)) 357 continue; 358 359 /* Same address. Share an NSM handle if we already have one */ 360 if (nsm == NULL) 361 nsm = host->h_nsmhandle; 362 363 if (host->h_proto != ni.protocol) 364 continue; 365 if (host->h_version != ni.version) 366 continue; 367 if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap)) 368 continue; 369 370 /* Move to head of hash chain. */ 371 hlist_del(&host->h_hash); 372 hlist_add_head(&host->h_hash, chain); 373 374 nlm_get_host(host); 375 dprintk("lockd: %s found host %s (%s)\n", 376 __func__, host->h_name, host->h_addrbuf); 377 goto out; 378 } 379 380 host = nlm_alloc_host(&ni, nsm); 381 if (unlikely(host == NULL)) 382 goto out; 383 384 memcpy(nlm_srcaddr(host), src_sap, src_len); 385 host->h_srcaddrlen = src_len; 386 hlist_add_head(&host->h_hash, chain); 387 ln->nrhosts++; 388 nrhosts++; 389 390 dprintk("lockd: %s created host %s (%s)\n", 391 __func__, host->h_name, host->h_addrbuf); 392 393out: 394 mutex_unlock(&nlm_host_mutex); 395 return host; 396} 397 398/** 399 * nlmsvc_release_host - release server nlm_host 400 * @host: nlm_host to release 401 * 402 * Host is destroyed later in nlm_gc_host(). 403 */ 404void nlmsvc_release_host(struct nlm_host *host) 405{ 406 if (host == NULL) 407 return; 408 409 dprintk("lockd: release server host %s\n", host->h_name); 410 411 WARN_ON_ONCE(!host->h_server); 412 atomic_dec(&host->h_count); 413} 414 415/* 416 * Create the NLM RPC client for an NLM peer 417 */ 418struct rpc_clnt * 419nlm_bind_host(struct nlm_host *host) 420{ 421 struct rpc_clnt *clnt; 422 423 dprintk("lockd: nlm_bind_host %s (%s)\n", 424 host->h_name, host->h_addrbuf); 425 426 /* Lock host handle */ 427 mutex_lock(&host->h_mutex); 428 429 /* If we've already created an RPC client, check whether 430 * RPC rebind is required 431 */ 432 if ((clnt = host->h_rpcclnt) != NULL) { 433 if (time_after_eq(jiffies, host->h_nextrebind)) { 434 rpc_force_rebind(clnt); 435 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 436 dprintk("lockd: next rebind in %lu jiffies\n", 437 host->h_nextrebind - jiffies); 438 } 439 } else { 440 unsigned long increment = nlmsvc_timeout; 441 struct rpc_timeout timeparms = { 442 .to_initval = increment, 443 .to_increment = increment, 444 .to_maxval = increment * 6UL, 445 .to_retries = 5U, 446 }; 447 struct rpc_create_args args = { 448 .net = host->net, 449 .protocol = host->h_proto, 450 .address = nlm_addr(host), 451 .addrsize = host->h_addrlen, 452 .timeout = &timeparms, 453 .servername = host->h_name, 454 .program = &nlm_program, 455 .version = host->h_version, 456 .authflavor = RPC_AUTH_UNIX, 457 .flags = (RPC_CLNT_CREATE_NOPING | 458 RPC_CLNT_CREATE_AUTOBIND), 459 }; 460 461 /* 462 * lockd retries server side blocks automatically so we want 463 * those to be soft RPC calls. Client side calls need to be 464 * hard RPC tasks. 465 */ 466 if (!host->h_server) 467 args.flags |= RPC_CLNT_CREATE_HARDRTRY; 468 if (host->h_noresvport) 469 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT; 470 if (host->h_srcaddrlen) 471 args.saddress = nlm_srcaddr(host); 472 473 clnt = rpc_create(&args); 474 if (!IS_ERR(clnt)) 475 host->h_rpcclnt = clnt; 476 else { 477 printk("lockd: couldn't create RPC handle for %s\n", host->h_name); 478 clnt = NULL; 479 } 480 } 481 482 mutex_unlock(&host->h_mutex); 483 return clnt; 484} 485 486/* 487 * Force a portmap lookup of the remote lockd port 488 */ 489void 490nlm_rebind_host(struct nlm_host *host) 491{ 492 dprintk("lockd: rebind host %s\n", host->h_name); 493 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) { 494 rpc_force_rebind(host->h_rpcclnt); 495 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 496 } 497} 498 499/* 500 * Increment NLM host count 501 */ 502struct nlm_host * nlm_get_host(struct nlm_host *host) 503{ 504 if (host) { 505 dprintk("lockd: get host %s\n", host->h_name); 506 atomic_inc(&host->h_count); 507 host->h_expires = jiffies + NLM_HOST_EXPIRE; 508 } 509 return host; 510} 511 512static struct nlm_host *next_host_state(struct hlist_head *cache, 513 struct nsm_handle *nsm, 514 const struct nlm_reboot *info) 515{ 516 struct nlm_host *host; 517 struct hlist_head *chain; 518 519 mutex_lock(&nlm_host_mutex); 520 for_each_host(host, chain, cache) { 521 if (host->h_nsmhandle == nsm 522 && host->h_nsmstate != info->state) { 523 host->h_nsmstate = info->state; 524 host->h_state++; 525 526 nlm_get_host(host); 527 mutex_unlock(&nlm_host_mutex); 528 return host; 529 } 530 } 531 532 mutex_unlock(&nlm_host_mutex); 533 return NULL; 534} 535 536/** 537 * nlm_host_rebooted - Release all resources held by rebooted host 538 * @net: network namespace 539 * @info: pointer to decoded results of NLM_SM_NOTIFY call 540 * 541 * We were notified that the specified host has rebooted. Release 542 * all resources held by that peer. 543 */ 544void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info) 545{ 546 struct nsm_handle *nsm; 547 struct nlm_host *host; 548 549 nsm = nsm_reboot_lookup(net, info); 550 if (unlikely(nsm == NULL)) 551 return; 552 553 /* Mark all hosts tied to this NSM state as having rebooted. 554 * We run the loop repeatedly, because we drop the host table 555 * lock for this. 556 * To avoid processing a host several times, we match the nsmstate. 557 */ 558 while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) { 559 nlmsvc_free_host_resources(host); 560 nlmsvc_release_host(host); 561 } 562 while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) { 563 nlmclnt_recovery(host); 564 nlmclnt_release_host(host); 565 } 566 567 nsm_release(nsm); 568} 569 570static void nlm_complain_hosts(struct net *net) 571{ 572 struct hlist_head *chain; 573 struct nlm_host *host; 574 575 if (net) { 576 struct lockd_net *ln = net_generic(net, lockd_net_id); 577 578 if (ln->nrhosts == 0) 579 return; 580 printk(KERN_WARNING "lockd: couldn't shutdown host module for net %p!\n", net); 581 dprintk("lockd: %lu hosts left in net %p:\n", ln->nrhosts, net); 582 } else { 583 if (nrhosts == 0) 584 return; 585 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n"); 586 dprintk("lockd: %lu hosts left:\n", nrhosts); 587 } 588 589 for_each_host(host, chain, nlm_server_hosts) { 590 if (net && host->net != net) 591 continue; 592 dprintk(" %s (cnt %d use %d exp %ld net %p)\n", 593 host->h_name, atomic_read(&host->h_count), 594 host->h_inuse, host->h_expires, host->net); 595 } 596} 597 598void 599nlm_shutdown_hosts_net(struct net *net) 600{ 601 struct hlist_head *chain; 602 struct nlm_host *host; 603 604 mutex_lock(&nlm_host_mutex); 605 606 /* First, make all hosts eligible for gc */ 607 dprintk("lockd: nuking all hosts in net %p...\n", net); 608 for_each_host(host, chain, nlm_server_hosts) { 609 if (net && host->net != net) 610 continue; 611 host->h_expires = jiffies - 1; 612 if (host->h_rpcclnt) { 613 rpc_shutdown_client(host->h_rpcclnt); 614 host->h_rpcclnt = NULL; 615 } 616 } 617 618 /* Then, perform a garbage collection pass */ 619 nlm_gc_hosts(net); 620 mutex_unlock(&nlm_host_mutex); 621 622 nlm_complain_hosts(net); 623} 624 625/* 626 * Shut down the hosts module. 627 * Note that this routine is called only at server shutdown time. 628 */ 629void 630nlm_shutdown_hosts(void) 631{ 632 dprintk("lockd: shutting down host module\n"); 633 nlm_shutdown_hosts_net(NULL); 634} 635 636/* 637 * Garbage collect any unused NLM hosts. 638 * This GC combines reference counting for async operations with 639 * mark & sweep for resources held by remote clients. 640 */ 641static void 642nlm_gc_hosts(struct net *net) 643{ 644 struct hlist_head *chain; 645 struct hlist_node *next; 646 struct nlm_host *host; 647 648 dprintk("lockd: host garbage collection for net %p\n", net); 649 for_each_host(host, chain, nlm_server_hosts) { 650 if (net && host->net != net) 651 continue; 652 host->h_inuse = 0; 653 } 654 655 /* Mark all hosts that hold locks, blocks or shares */ 656 nlmsvc_mark_resources(net); 657 658 for_each_host_safe(host, next, chain, nlm_server_hosts) { 659 if (net && host->net != net) 660 continue; 661 if (atomic_read(&host->h_count) || host->h_inuse 662 || time_before(jiffies, host->h_expires)) { 663 dprintk("nlm_gc_hosts skipping %s " 664 "(cnt %d use %d exp %ld net %p)\n", 665 host->h_name, atomic_read(&host->h_count), 666 host->h_inuse, host->h_expires, host->net); 667 continue; 668 } 669 nlm_destroy_host_locked(host); 670 } 671 672 if (net) { 673 struct lockd_net *ln = net_generic(net, lockd_net_id); 674 675 ln->next_gc = jiffies + NLM_HOST_COLLECT; 676 } 677} 678