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_mutex_lock(&host->h_count, &nlm_host_mutex)) { 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 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 */ 321 struct 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 refcount_inc(&host->h_count); 391 392 dprintk("lockd: %s created host %s (%s)\n", 393 __func__, host->h_name, host->h_addrbuf); 394 395 out: 396 mutex_unlock(&nlm_host_mutex); 397 return host; 398 } 399 400 /** 401 * nlmsvc_release_host - release server nlm_host 402 * @host: nlm_host to release 403 * 404 * Host is destroyed later in nlm_gc_host(). 405 */ 406 void nlmsvc_release_host(struct nlm_host *host) 407 { 408 if (host == NULL) 409 return; 410 411 dprintk("lockd: release server host %s\n", host->h_name); 412 413 WARN_ON_ONCE(!host->h_server); 414 refcount_dec(&host->h_count); 415 } 416 417 /* 418 * Create the NLM RPC client for an NLM peer 419 */ 420 struct rpc_clnt * 421 nlm_bind_host(struct nlm_host *host) 422 { 423 struct rpc_clnt *clnt; 424 425 dprintk("lockd: nlm_bind_host %s (%s)\n", 426 host->h_name, host->h_addrbuf); 427 428 /* Lock host handle */ 429 mutex_lock(&host->h_mutex); 430 431 /* If we've already created an RPC client, check whether 432 * RPC rebind is required 433 */ 434 if ((clnt = host->h_rpcclnt) != NULL) { 435 if (time_after_eq(jiffies, host->h_nextrebind)) { 436 rpc_force_rebind(clnt); 437 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 438 dprintk("lockd: next rebind in %lu jiffies\n", 439 host->h_nextrebind - jiffies); 440 } 441 } else { 442 unsigned long increment = nlmsvc_timeout; 443 struct rpc_timeout timeparms = { 444 .to_initval = increment, 445 .to_increment = increment, 446 .to_maxval = increment * 6UL, 447 .to_retries = 5U, 448 }; 449 struct rpc_create_args args = { 450 .net = host->net, 451 .protocol = host->h_proto, 452 .address = nlm_addr(host), 453 .addrsize = host->h_addrlen, 454 .timeout = &timeparms, 455 .servername = host->h_name, 456 .program = &nlm_program, 457 .version = host->h_version, 458 .authflavor = RPC_AUTH_UNIX, 459 .flags = (RPC_CLNT_CREATE_NOPING | 460 RPC_CLNT_CREATE_AUTOBIND), 461 }; 462 463 /* 464 * lockd retries server side blocks automatically so we want 465 * those to be soft RPC calls. Client side calls need to be 466 * hard RPC tasks. 467 */ 468 if (!host->h_server) 469 args.flags |= RPC_CLNT_CREATE_HARDRTRY; 470 if (host->h_noresvport) 471 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT; 472 if (host->h_srcaddrlen) 473 args.saddress = nlm_srcaddr(host); 474 475 clnt = rpc_create(&args); 476 if (!IS_ERR(clnt)) 477 host->h_rpcclnt = clnt; 478 else { 479 printk("lockd: couldn't create RPC handle for %s\n", host->h_name); 480 clnt = NULL; 481 } 482 } 483 484 mutex_unlock(&host->h_mutex); 485 return clnt; 486 } 487 488 /* 489 * Force a portmap lookup of the remote lockd port 490 */ 491 void 492 nlm_rebind_host(struct nlm_host *host) 493 { 494 dprintk("lockd: rebind host %s\n", host->h_name); 495 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) { 496 rpc_force_rebind(host->h_rpcclnt); 497 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 498 } 499 } 500 501 /* 502 * Increment NLM host count 503 */ 504 struct nlm_host * nlm_get_host(struct nlm_host *host) 505 { 506 if (host) { 507 dprintk("lockd: get host %s\n", host->h_name); 508 refcount_inc(&host->h_count); 509 host->h_expires = jiffies + NLM_HOST_EXPIRE; 510 } 511 return host; 512 } 513 514 static struct nlm_host *next_host_state(struct hlist_head *cache, 515 struct nsm_handle *nsm, 516 const struct nlm_reboot *info) 517 { 518 struct nlm_host *host; 519 struct hlist_head *chain; 520 521 mutex_lock(&nlm_host_mutex); 522 for_each_host(host, chain, cache) { 523 if (host->h_nsmhandle == nsm 524 && host->h_nsmstate != info->state) { 525 host->h_nsmstate = info->state; 526 host->h_state++; 527 528 nlm_get_host(host); 529 mutex_unlock(&nlm_host_mutex); 530 return host; 531 } 532 } 533 534 mutex_unlock(&nlm_host_mutex); 535 return NULL; 536 } 537 538 /** 539 * nlm_host_rebooted - Release all resources held by rebooted host 540 * @net: network namespace 541 * @info: pointer to decoded results of NLM_SM_NOTIFY call 542 * 543 * We were notified that the specified host has rebooted. Release 544 * all resources held by that peer. 545 */ 546 void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info) 547 { 548 struct nsm_handle *nsm; 549 struct nlm_host *host; 550 551 nsm = nsm_reboot_lookup(net, info); 552 if (unlikely(nsm == NULL)) 553 return; 554 555 /* Mark all hosts tied to this NSM state as having rebooted. 556 * We run the loop repeatedly, because we drop the host table 557 * lock for this. 558 * To avoid processing a host several times, we match the nsmstate. 559 */ 560 while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) { 561 nlmsvc_free_host_resources(host); 562 nlmsvc_release_host(host); 563 } 564 while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) { 565 nlmclnt_recovery(host); 566 nlmclnt_release_host(host); 567 } 568 569 nsm_release(nsm); 570 } 571 572 static void nlm_complain_hosts(struct net *net) 573 { 574 struct hlist_head *chain; 575 struct nlm_host *host; 576 577 if (net) { 578 struct lockd_net *ln = net_generic(net, lockd_net_id); 579 580 if (ln->nrhosts == 0) 581 return; 582 pr_warn("lockd: couldn't shutdown host module for net %x!\n", 583 net->ns.inum); 584 dprintk("lockd: %lu hosts left in net %x:\n", ln->nrhosts, 585 net->ns.inum); 586 } else { 587 if (nrhosts == 0) 588 return; 589 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n"); 590 dprintk("lockd: %lu hosts left:\n", nrhosts); 591 } 592 593 for_each_host(host, chain, nlm_server_hosts) { 594 if (net && host->net != net) 595 continue; 596 dprintk(" %s (cnt %d use %d exp %ld net %x)\n", 597 host->h_name, refcount_read(&host->h_count), 598 host->h_inuse, host->h_expires, host->net->ns.inum); 599 } 600 } 601 602 void 603 nlm_shutdown_hosts_net(struct net *net) 604 { 605 struct hlist_head *chain; 606 struct nlm_host *host; 607 608 mutex_lock(&nlm_host_mutex); 609 610 /* First, make all hosts eligible for gc */ 611 dprintk("lockd: nuking all hosts in net %x...\n", 612 net ? net->ns.inum : 0); 613 for_each_host(host, chain, nlm_server_hosts) { 614 if (net && host->net != net) 615 continue; 616 host->h_expires = jiffies - 1; 617 if (host->h_rpcclnt) { 618 rpc_shutdown_client(host->h_rpcclnt); 619 host->h_rpcclnt = NULL; 620 } 621 } 622 623 /* Then, perform a garbage collection pass */ 624 nlm_gc_hosts(net); 625 nlm_complain_hosts(net); 626 mutex_unlock(&nlm_host_mutex); 627 } 628 629 /* 630 * Shut down the hosts module. 631 * Note that this routine is called only at server shutdown time. 632 */ 633 void 634 nlm_shutdown_hosts(void) 635 { 636 dprintk("lockd: shutting down host module\n"); 637 nlm_shutdown_hosts_net(NULL); 638 } 639 640 /* 641 * Garbage collect any unused NLM hosts. 642 * This GC combines reference counting for async operations with 643 * mark & sweep for resources held by remote clients. 644 */ 645 static void 646 nlm_gc_hosts(struct net *net) 647 { 648 struct hlist_head *chain; 649 struct hlist_node *next; 650 struct nlm_host *host; 651 652 dprintk("lockd: host garbage collection for net %x\n", 653 net ? net->ns.inum : 0); 654 for_each_host(host, chain, nlm_server_hosts) { 655 if (net && host->net != net) 656 continue; 657 host->h_inuse = 0; 658 } 659 660 /* Mark all hosts that hold locks, blocks or shares */ 661 nlmsvc_mark_resources(net); 662 663 for_each_host_safe(host, next, chain, nlm_server_hosts) { 664 if (net && host->net != net) 665 continue; 666 if (host->h_inuse || time_before(jiffies, host->h_expires)) { 667 dprintk("nlm_gc_hosts skipping %s " 668 "(cnt %d use %d exp %ld net %x)\n", 669 host->h_name, refcount_read(&host->h_count), 670 host->h_inuse, host->h_expires, 671 host->net->ns.inum); 672 continue; 673 } 674 if (refcount_dec_if_one(&host->h_count)) 675 nlm_destroy_host_locked(host); 676 } 677 678 if (net) { 679 struct lockd_net *ln = net_generic(net, lockd_net_id); 680 681 ln->next_gc = jiffies + NLM_HOST_COLLECT; 682 } 683 } 684