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