1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/lockd/host.c 4 * 5 * Management for NLM peer hosts. The nlm_host struct is shared 6 * between client and server implementation. The only reason to 7 * do so is to reduce code bloat. 8 * 9 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 10 */ 11 12 #include <linux/types.h> 13 #include <linux/slab.h> 14 #include <linux/in.h> 15 #include <linux/in6.h> 16 #include <linux/sunrpc/clnt.h> 17 #include <linux/sunrpc/addr.h> 18 #include <linux/sunrpc/svc.h> 19 #include <linux/lockd/lockd.h> 20 #include <linux/mutex.h> 21 22 #include <linux/sunrpc/svc_xprt.h> 23 24 #include <net/ipv6.h> 25 26 #include "netns.h" 27 28 #define NLMDBG_FACILITY NLMDBG_HOSTCACHE 29 #define NLM_HOST_NRHASH 32 30 #define NLM_HOST_REBIND (60 * HZ) 31 #define NLM_HOST_EXPIRE (300 * HZ) 32 #define NLM_HOST_COLLECT (120 * HZ) 33 34 static struct hlist_head nlm_server_hosts[NLM_HOST_NRHASH]; 35 static struct hlist_head nlm_client_hosts[NLM_HOST_NRHASH]; 36 37 #define for_each_host(host, chain, table) \ 38 for ((chain) = (table); \ 39 (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \ 40 hlist_for_each_entry((host), (chain), h_hash) 41 42 #define for_each_host_safe(host, next, chain, table) \ 43 for ((chain) = (table); \ 44 (chain) < (table) + NLM_HOST_NRHASH; ++(chain)) \ 45 hlist_for_each_entry_safe((host), (next), \ 46 (chain), h_hash) 47 48 static unsigned long nrhosts; 49 static DEFINE_MUTEX(nlm_host_mutex); 50 51 static void nlm_gc_hosts(struct net *net); 52 53 struct nlm_lookup_host_info { 54 const int server; /* search for server|client */ 55 const struct sockaddr *sap; /* address to search for */ 56 const size_t salen; /* it's length */ 57 const unsigned short protocol; /* transport to search for*/ 58 const u32 version; /* NLM version to search for */ 59 const char *hostname; /* remote's hostname */ 60 const size_t hostname_len; /* it's length */ 61 const int noresvport; /* use non-priv port */ 62 struct net *net; /* network namespace to bind */ 63 }; 64 65 /* 66 * Hash function must work well on big- and little-endian platforms 67 */ 68 static unsigned int __nlm_hash32(const __be32 n) 69 { 70 unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16); 71 return hash ^ (hash >> 8); 72 } 73 74 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap) 75 { 76 const struct sockaddr_in *sin = (struct sockaddr_in *)sap; 77 return __nlm_hash32(sin->sin_addr.s_addr); 78 } 79 80 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap) 81 { 82 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap; 83 const struct in6_addr addr = sin6->sin6_addr; 84 return __nlm_hash32(addr.s6_addr32[0]) ^ 85 __nlm_hash32(addr.s6_addr32[1]) ^ 86 __nlm_hash32(addr.s6_addr32[2]) ^ 87 __nlm_hash32(addr.s6_addr32[3]); 88 } 89 90 static unsigned int nlm_hash_address(const struct sockaddr *sap) 91 { 92 unsigned int hash; 93 94 switch (sap->sa_family) { 95 case AF_INET: 96 hash = __nlm_hash_addr4(sap); 97 break; 98 case AF_INET6: 99 hash = __nlm_hash_addr6(sap); 100 break; 101 default: 102 hash = 0; 103 } 104 return hash & (NLM_HOST_NRHASH - 1); 105 } 106 107 /* 108 * Allocate and initialize an nlm_host. Common to both client and server. 109 */ 110 static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni, 111 struct nsm_handle *nsm) 112 { 113 struct nlm_host *host = NULL; 114 unsigned long now = jiffies; 115 116 if (nsm != NULL) 117 refcount_inc(&nsm->sm_count); 118 else { 119 host = NULL; 120 nsm = nsm_get_handle(ni->net, ni->sap, ni->salen, 121 ni->hostname, ni->hostname_len); 122 if (unlikely(nsm == NULL)) { 123 dprintk("lockd: %s failed; no nsm handle\n", 124 __func__); 125 goto out; 126 } 127 } 128 129 host = kmalloc(sizeof(*host), GFP_KERNEL); 130 if (unlikely(host == NULL)) { 131 dprintk("lockd: %s failed; no memory\n", __func__); 132 nsm_release(nsm); 133 goto out; 134 } 135 136 memcpy(nlm_addr(host), ni->sap, ni->salen); 137 host->h_addrlen = ni->salen; 138 rpc_set_port(nlm_addr(host), 0); 139 host->h_srcaddrlen = 0; 140 141 host->h_rpcclnt = NULL; 142 host->h_name = nsm->sm_name; 143 host->h_version = ni->version; 144 host->h_proto = ni->protocol; 145 host->h_reclaiming = 0; 146 host->h_server = ni->server; 147 host->h_noresvport = ni->noresvport; 148 host->h_inuse = 0; 149 init_waitqueue_head(&host->h_gracewait); 150 init_rwsem(&host->h_rwsem); 151 host->h_state = 0; 152 host->h_nsmstate = 0; 153 host->h_pidcount = 0; 154 refcount_set(&host->h_count, 1); 155 mutex_init(&host->h_mutex); 156 host->h_nextrebind = now + NLM_HOST_REBIND; 157 host->h_expires = now + NLM_HOST_EXPIRE; 158 INIT_LIST_HEAD(&host->h_lockowners); 159 spin_lock_init(&host->h_lock); 160 INIT_LIST_HEAD(&host->h_granted); 161 INIT_LIST_HEAD(&host->h_reclaim); 162 host->h_nsmhandle = nsm; 163 host->h_addrbuf = nsm->sm_addrbuf; 164 host->net = ni->net; 165 strlcpy(host->nodename, utsname()->nodename, sizeof(host->nodename)); 166 167 out: 168 return host; 169 } 170 171 /* 172 * Destroy an nlm_host and free associated resources 173 * 174 * Caller must hold nlm_host_mutex. 175 */ 176 static void nlm_destroy_host_locked(struct nlm_host *host) 177 { 178 struct rpc_clnt *clnt; 179 struct lockd_net *ln = net_generic(host->net, lockd_net_id); 180 181 dprintk("lockd: destroy host %s\n", host->h_name); 182 183 hlist_del_init(&host->h_hash); 184 185 nsm_unmonitor(host); 186 nsm_release(host->h_nsmhandle); 187 188 clnt = host->h_rpcclnt; 189 if (clnt != NULL) 190 rpc_shutdown_client(clnt); 191 kfree(host); 192 193 ln->nrhosts--; 194 nrhosts--; 195 } 196 197 /** 198 * nlmclnt_lookup_host - Find an NLM host handle matching a remote server 199 * @sap: network address of server 200 * @salen: length of server address 201 * @protocol: transport protocol to use 202 * @version: NLM protocol version 203 * @hostname: '\0'-terminated hostname of server 204 * @noresvport: 1 if non-privileged port should be used 205 * 206 * Returns an nlm_host structure that matches the passed-in 207 * [server address, transport protocol, NLM version, server hostname]. 208 * If one doesn't already exist in the host cache, a new handle is 209 * created and returned. 210 */ 211 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap, 212 const size_t salen, 213 const unsigned short protocol, 214 const u32 version, 215 const char *hostname, 216 int noresvport, 217 struct net *net) 218 { 219 struct nlm_lookup_host_info ni = { 220 .server = 0, 221 .sap = sap, 222 .salen = salen, 223 .protocol = protocol, 224 .version = version, 225 .hostname = hostname, 226 .hostname_len = strlen(hostname), 227 .noresvport = noresvport, 228 .net = net, 229 }; 230 struct hlist_head *chain; 231 struct nlm_host *host; 232 struct nsm_handle *nsm = NULL; 233 struct lockd_net *ln = net_generic(net, lockd_net_id); 234 235 dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__, 236 (hostname ? hostname : "<none>"), version, 237 (protocol == IPPROTO_UDP ? "udp" : "tcp")); 238 239 mutex_lock(&nlm_host_mutex); 240 241 chain = &nlm_client_hosts[nlm_hash_address(sap)]; 242 hlist_for_each_entry(host, chain, h_hash) { 243 if (host->net != net) 244 continue; 245 if (!rpc_cmp_addr(nlm_addr(host), sap)) 246 continue; 247 248 /* Same address. Share an NSM handle if we already have one */ 249 if (nsm == NULL) 250 nsm = host->h_nsmhandle; 251 252 if (host->h_proto != protocol) 253 continue; 254 if (host->h_version != version) 255 continue; 256 257 nlm_get_host(host); 258 dprintk("lockd: %s found host %s (%s)\n", __func__, 259 host->h_name, host->h_addrbuf); 260 goto out; 261 } 262 263 host = nlm_alloc_host(&ni, nsm); 264 if (unlikely(host == NULL)) 265 goto out; 266 267 hlist_add_head(&host->h_hash, chain); 268 ln->nrhosts++; 269 nrhosts++; 270 271 dprintk("lockd: %s created host %s (%s)\n", __func__, 272 host->h_name, host->h_addrbuf); 273 274 out: 275 mutex_unlock(&nlm_host_mutex); 276 return host; 277 } 278 279 /** 280 * nlmclnt_release_host - release client nlm_host 281 * @host: nlm_host to release 282 * 283 */ 284 void nlmclnt_release_host(struct nlm_host *host) 285 { 286 if (host == NULL) 287 return; 288 289 dprintk("lockd: release client host %s\n", host->h_name); 290 291 WARN_ON_ONCE(host->h_server); 292 293 if (refcount_dec_and_test(&host->h_count)) { 294 WARN_ON_ONCE(!list_empty(&host->h_lockowners)); 295 WARN_ON_ONCE(!list_empty(&host->h_granted)); 296 WARN_ON_ONCE(!list_empty(&host->h_reclaim)); 297 298 mutex_lock(&nlm_host_mutex); 299 nlm_destroy_host_locked(host); 300 mutex_unlock(&nlm_host_mutex); 301 } 302 } 303 304 /** 305 * nlmsvc_lookup_host - Find an NLM host handle matching a remote client 306 * @rqstp: incoming NLM request 307 * @hostname: name of client host 308 * @hostname_len: length of client hostname 309 * 310 * Returns an nlm_host structure that matches the [client address, 311 * transport protocol, NLM version, client hostname] of the passed-in 312 * NLM request. If one doesn't already exist in the host cache, a 313 * new handle is created and returned. 314 * 315 * Before possibly creating a new nlm_host, construct a sockaddr 316 * for a specific source address in case the local system has 317 * multiple network addresses. The family of the address in 318 * rq_daddr is guaranteed to be the same as the family of the 319 * address in rq_addr, so it's safe to use the same family for 320 * the source address. 321 */ 322 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp, 323 const char *hostname, 324 const size_t hostname_len) 325 { 326 struct hlist_head *chain; 327 struct nlm_host *host = NULL; 328 struct nsm_handle *nsm = NULL; 329 struct sockaddr *src_sap = svc_daddr(rqstp); 330 size_t src_len = rqstp->rq_daddrlen; 331 struct net *net = SVC_NET(rqstp); 332 struct nlm_lookup_host_info ni = { 333 .server = 1, 334 .sap = svc_addr(rqstp), 335 .salen = rqstp->rq_addrlen, 336 .protocol = rqstp->rq_prot, 337 .version = rqstp->rq_vers, 338 .hostname = hostname, 339 .hostname_len = hostname_len, 340 .net = net, 341 }; 342 struct lockd_net *ln = net_generic(net, lockd_net_id); 343 344 dprintk("lockd: %s(host='%.*s', vers=%u, proto=%s)\n", __func__, 345 (int)hostname_len, hostname, rqstp->rq_vers, 346 (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp")); 347 348 mutex_lock(&nlm_host_mutex); 349 350 if (time_after_eq(jiffies, ln->next_gc)) 351 nlm_gc_hosts(net); 352 353 chain = &nlm_server_hosts[nlm_hash_address(ni.sap)]; 354 hlist_for_each_entry(host, chain, h_hash) { 355 if (host->net != net) 356 continue; 357 if (!rpc_cmp_addr(nlm_addr(host), ni.sap)) 358 continue; 359 360 /* Same address. Share an NSM handle if we already have one */ 361 if (nsm == NULL) 362 nsm = host->h_nsmhandle; 363 364 if (host->h_proto != ni.protocol) 365 continue; 366 if (host->h_version != ni.version) 367 continue; 368 if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap)) 369 continue; 370 371 /* Move to head of hash chain. */ 372 hlist_del(&host->h_hash); 373 hlist_add_head(&host->h_hash, chain); 374 375 nlm_get_host(host); 376 dprintk("lockd: %s found host %s (%s)\n", 377 __func__, host->h_name, host->h_addrbuf); 378 goto out; 379 } 380 381 host = nlm_alloc_host(&ni, nsm); 382 if (unlikely(host == NULL)) 383 goto out; 384 385 memcpy(nlm_srcaddr(host), src_sap, src_len); 386 host->h_srcaddrlen = src_len; 387 hlist_add_head(&host->h_hash, chain); 388 ln->nrhosts++; 389 nrhosts++; 390 391 refcount_inc(&host->h_count); 392 393 dprintk("lockd: %s created host %s (%s)\n", 394 __func__, host->h_name, host->h_addrbuf); 395 396 out: 397 mutex_unlock(&nlm_host_mutex); 398 return host; 399 } 400 401 /** 402 * nlmsvc_release_host - release server nlm_host 403 * @host: nlm_host to release 404 * 405 * Host is destroyed later in nlm_gc_host(). 406 */ 407 void nlmsvc_release_host(struct nlm_host *host) 408 { 409 if (host == NULL) 410 return; 411 412 dprintk("lockd: release server host %s\n", host->h_name); 413 414 WARN_ON_ONCE(!host->h_server); 415 refcount_dec(&host->h_count); 416 } 417 418 /* 419 * Create the NLM RPC client for an NLM peer 420 */ 421 struct rpc_clnt * 422 nlm_bind_host(struct nlm_host *host) 423 { 424 struct rpc_clnt *clnt; 425 426 dprintk("lockd: nlm_bind_host %s (%s)\n", 427 host->h_name, host->h_addrbuf); 428 429 /* Lock host handle */ 430 mutex_lock(&host->h_mutex); 431 432 /* If we've already created an RPC client, check whether 433 * RPC rebind is required 434 */ 435 if ((clnt = host->h_rpcclnt) != NULL) { 436 if (time_after_eq(jiffies, host->h_nextrebind)) { 437 rpc_force_rebind(clnt); 438 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 439 dprintk("lockd: next rebind in %lu jiffies\n", 440 host->h_nextrebind - jiffies); 441 } 442 } else { 443 unsigned long increment = nlmsvc_timeout; 444 struct rpc_timeout timeparms = { 445 .to_initval = increment, 446 .to_increment = increment, 447 .to_maxval = increment * 6UL, 448 .to_retries = 5U, 449 }; 450 struct rpc_create_args args = { 451 .net = host->net, 452 .protocol = host->h_proto, 453 .address = nlm_addr(host), 454 .addrsize = host->h_addrlen, 455 .timeout = &timeparms, 456 .servername = host->h_name, 457 .program = &nlm_program, 458 .version = host->h_version, 459 .authflavor = RPC_AUTH_UNIX, 460 .flags = (RPC_CLNT_CREATE_NOPING | 461 RPC_CLNT_CREATE_AUTOBIND), 462 }; 463 464 /* 465 * lockd retries server side blocks automatically so we want 466 * those to be soft RPC calls. Client side calls need to be 467 * hard RPC tasks. 468 */ 469 if (!host->h_server) 470 args.flags |= RPC_CLNT_CREATE_HARDRTRY; 471 if (host->h_noresvport) 472 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT; 473 if (host->h_srcaddrlen) 474 args.saddress = nlm_srcaddr(host); 475 476 clnt = rpc_create(&args); 477 if (!IS_ERR(clnt)) 478 host->h_rpcclnt = clnt; 479 else { 480 printk("lockd: couldn't create RPC handle for %s\n", host->h_name); 481 clnt = NULL; 482 } 483 } 484 485 mutex_unlock(&host->h_mutex); 486 return clnt; 487 } 488 489 /* 490 * Force a portmap lookup of the remote lockd port 491 */ 492 void 493 nlm_rebind_host(struct nlm_host *host) 494 { 495 dprintk("lockd: rebind host %s\n", host->h_name); 496 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) { 497 rpc_force_rebind(host->h_rpcclnt); 498 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 499 } 500 } 501 502 /* 503 * Increment NLM host count 504 */ 505 struct nlm_host * nlm_get_host(struct nlm_host *host) 506 { 507 if (host) { 508 dprintk("lockd: get host %s\n", host->h_name); 509 refcount_inc(&host->h_count); 510 host->h_expires = jiffies + NLM_HOST_EXPIRE; 511 } 512 return host; 513 } 514 515 static struct nlm_host *next_host_state(struct hlist_head *cache, 516 struct nsm_handle *nsm, 517 const struct nlm_reboot *info) 518 { 519 struct nlm_host *host; 520 struct hlist_head *chain; 521 522 mutex_lock(&nlm_host_mutex); 523 for_each_host(host, chain, cache) { 524 if (host->h_nsmhandle == nsm 525 && host->h_nsmstate != info->state) { 526 host->h_nsmstate = info->state; 527 host->h_state++; 528 529 nlm_get_host(host); 530 mutex_unlock(&nlm_host_mutex); 531 return host; 532 } 533 } 534 535 mutex_unlock(&nlm_host_mutex); 536 return NULL; 537 } 538 539 /** 540 * nlm_host_rebooted - Release all resources held by rebooted host 541 * @net: network namespace 542 * @info: pointer to decoded results of NLM_SM_NOTIFY call 543 * 544 * We were notified that the specified host has rebooted. Release 545 * all resources held by that peer. 546 */ 547 void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info) 548 { 549 struct nsm_handle *nsm; 550 struct nlm_host *host; 551 552 nsm = nsm_reboot_lookup(net, info); 553 if (unlikely(nsm == NULL)) 554 return; 555 556 /* Mark all hosts tied to this NSM state as having rebooted. 557 * We run the loop repeatedly, because we drop the host table 558 * lock for this. 559 * To avoid processing a host several times, we match the nsmstate. 560 */ 561 while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) { 562 nlmsvc_free_host_resources(host); 563 nlmsvc_release_host(host); 564 } 565 while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) { 566 nlmclnt_recovery(host); 567 nlmclnt_release_host(host); 568 } 569 570 nsm_release(nsm); 571 } 572 573 static void nlm_complain_hosts(struct net *net) 574 { 575 struct hlist_head *chain; 576 struct nlm_host *host; 577 578 if (net) { 579 struct lockd_net *ln = net_generic(net, lockd_net_id); 580 581 if (ln->nrhosts == 0) 582 return; 583 pr_warn("lockd: couldn't shutdown host module for net %x!\n", 584 net->ns.inum); 585 dprintk("lockd: %lu hosts left in net %x:\n", ln->nrhosts, 586 net->ns.inum); 587 } else { 588 if (nrhosts == 0) 589 return; 590 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n"); 591 dprintk("lockd: %lu hosts left:\n", nrhosts); 592 } 593 594 for_each_host(host, chain, nlm_server_hosts) { 595 if (net && host->net != net) 596 continue; 597 dprintk(" %s (cnt %d use %d exp %ld net %x)\n", 598 host->h_name, refcount_read(&host->h_count), 599 host->h_inuse, host->h_expires, host->net->ns.inum); 600 } 601 } 602 603 void 604 nlm_shutdown_hosts_net(struct net *net) 605 { 606 struct hlist_head *chain; 607 struct nlm_host *host; 608 609 mutex_lock(&nlm_host_mutex); 610 611 /* First, make all hosts eligible for gc */ 612 dprintk("lockd: nuking all hosts in net %x...\n", 613 net ? net->ns.inum : 0); 614 for_each_host(host, chain, nlm_server_hosts) { 615 if (net && host->net != net) 616 continue; 617 host->h_expires = jiffies - 1; 618 if (host->h_rpcclnt) { 619 rpc_shutdown_client(host->h_rpcclnt); 620 host->h_rpcclnt = NULL; 621 } 622 } 623 624 /* Then, perform a garbage collection pass */ 625 nlm_gc_hosts(net); 626 nlm_complain_hosts(net); 627 mutex_unlock(&nlm_host_mutex); 628 } 629 630 /* 631 * Shut down the hosts module. 632 * Note that this routine is called only at server shutdown time. 633 */ 634 void 635 nlm_shutdown_hosts(void) 636 { 637 dprintk("lockd: shutting down host module\n"); 638 nlm_shutdown_hosts_net(NULL); 639 } 640 641 /* 642 * Garbage collect any unused NLM hosts. 643 * This GC combines reference counting for async operations with 644 * mark & sweep for resources held by remote clients. 645 */ 646 static void 647 nlm_gc_hosts(struct net *net) 648 { 649 struct hlist_head *chain; 650 struct hlist_node *next; 651 struct nlm_host *host; 652 653 dprintk("lockd: host garbage collection for net %x\n", 654 net ? net->ns.inum : 0); 655 for_each_host(host, chain, nlm_server_hosts) { 656 if (net && host->net != net) 657 continue; 658 host->h_inuse = 0; 659 } 660 661 /* Mark all hosts that hold locks, blocks or shares */ 662 nlmsvc_mark_resources(net); 663 664 for_each_host_safe(host, next, chain, nlm_server_hosts) { 665 if (net && host->net != net) 666 continue; 667 if (host->h_inuse || time_before(jiffies, host->h_expires)) { 668 dprintk("nlm_gc_hosts skipping %s " 669 "(cnt %d use %d exp %ld net %x)\n", 670 host->h_name, refcount_read(&host->h_count), 671 host->h_inuse, host->h_expires, 672 host->net->ns.inum); 673 continue; 674 } 675 if (refcount_dec_if_one(&host->h_count)) 676 nlm_destroy_host_locked(host); 677 } 678 679 if (net) { 680 struct lockd_net *ln = net_generic(net, lockd_net_id); 681 682 ln->next_gc = jiffies + NLM_HOST_COLLECT; 683 } 684 } 685