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 const struct cred *cred;
64 };
65
66 /*
67 * Hash function must work well on big- and little-endian platforms
68 */
69 static unsigned int __nlm_hash32(const __be32 n)
70 {
71 unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
72 return hash ^ (hash >> 8);
73 }
74
75 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
76 {
77 const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
78 return __nlm_hash32(sin->sin_addr.s_addr);
79 }
80
81 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
82 {
83 const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
84 const struct in6_addr addr = sin6->sin6_addr;
85 return __nlm_hash32(addr.s6_addr32[0]) ^
86 __nlm_hash32(addr.s6_addr32[1]) ^
87 __nlm_hash32(addr.s6_addr32[2]) ^
88 __nlm_hash32(addr.s6_addr32[3]);
89 }
90
91 static unsigned int nlm_hash_address(const struct sockaddr *sap)
92 {
93 unsigned int hash;
94
95 switch (sap->sa_family) {
96 case AF_INET:
97 hash = __nlm_hash_addr4(sap);
98 break;
99 case AF_INET6:
100 hash = __nlm_hash_addr6(sap);
101 break;
102 default:
103 hash = 0;
104 }
105 return hash & (NLM_HOST_NRHASH - 1);
106 }
107
108 /*
109 * Allocate and initialize an nlm_host. Common to both client and server.
110 */
111 static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni,
112 struct nsm_handle *nsm)
113 {
114 struct nlm_host *host = NULL;
115 unsigned long now = jiffies;
116
117 if (nsm != NULL)
118 refcount_inc(&nsm->sm_count);
119 else {
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 host->h_cred = get_cred(ni->cred);
166 strscpy(host->nodename, utsname()->nodename, sizeof(host->nodename));
167
168 out:
169 return host;
170 }
171
172 /*
173 * Destroy an nlm_host and free associated resources
174 *
175 * Caller must hold nlm_host_mutex.
176 */
177 static void nlm_destroy_host_locked(struct nlm_host *host)
178 {
179 struct rpc_clnt *clnt;
180 struct lockd_net *ln = net_generic(host->net, lockd_net_id);
181
182 dprintk("lockd: destroy host %s\n", host->h_name);
183
184 hlist_del_init(&host->h_hash);
185
186 nsm_unmonitor(host);
187 nsm_release(host->h_nsmhandle);
188
189 clnt = host->h_rpcclnt;
190 if (clnt != NULL)
191 rpc_shutdown_client(clnt);
192 put_cred(host->h_cred);
193 kfree(host);
194
195 ln->nrhosts--;
196 nrhosts--;
197 }
198
199 /**
200 * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
201 * @sap: network address of server
202 * @salen: length of server address
203 * @protocol: transport protocol to use
204 * @version: NLM protocol version
205 * @hostname: '\0'-terminated hostname of server
206 * @noresvport: 1 if non-privileged port should be used
207 * @net: pointer to net namespace
208 * @cred: pointer to cred
209 *
210 * Returns an nlm_host structure that matches the passed-in
211 * [server address, transport protocol, NLM version, server hostname].
212 * If one doesn't already exist in the host cache, a new handle is
213 * created and returned.
214 */
215 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
216 const size_t salen,
217 const unsigned short protocol,
218 const u32 version,
219 const char *hostname,
220 int noresvport,
221 struct net *net,
222 const struct cred *cred)
223 {
224 struct nlm_lookup_host_info ni = {
225 .server = 0,
226 .sap = sap,
227 .salen = salen,
228 .protocol = protocol,
229 .version = version,
230 .hostname = hostname,
231 .hostname_len = strlen(hostname),
232 .noresvport = noresvport,
233 .net = net,
234 .cred = cred,
235 };
236 struct hlist_head *chain;
237 struct nlm_host *host;
238 struct nsm_handle *nsm = NULL;
239 struct lockd_net *ln = net_generic(net, lockd_net_id);
240
241 dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
242 (hostname ? hostname : "<none>"), version,
243 (protocol == IPPROTO_UDP ? "udp" : "tcp"));
244
245 mutex_lock(&nlm_host_mutex);
246
247 chain = &nlm_client_hosts[nlm_hash_address(sap)];
248 hlist_for_each_entry(host, chain, h_hash) {
249 if (host->net != net)
250 continue;
251 if (!rpc_cmp_addr(nlm_addr(host), sap))
252 continue;
253
254 /* Same address. Share an NSM handle if we already have one */
255 if (nsm == NULL)
256 nsm = host->h_nsmhandle;
257
258 if (host->h_proto != protocol)
259 continue;
260 if (host->h_version != version)
261 continue;
262
263 nlm_get_host(host);
264 dprintk("lockd: %s found host %s (%s)\n", __func__,
265 host->h_name, host->h_addrbuf);
266 goto out;
267 }
268
269 host = nlm_alloc_host(&ni, nsm);
270 if (unlikely(host == NULL))
271 goto out;
272
273 hlist_add_head(&host->h_hash, chain);
274 ln->nrhosts++;
275 nrhosts++;
276
277 dprintk("lockd: %s created host %s (%s)\n", __func__,
278 host->h_name, host->h_addrbuf);
279
280 out:
281 mutex_unlock(&nlm_host_mutex);
282 return host;
283 }
284
285 /**
286 * nlmclnt_release_host - release client nlm_host
287 * @host: nlm_host to release
288 *
289 */
290 void nlmclnt_release_host(struct nlm_host *host)
291 {
292 if (host == NULL)
293 return;
294
295 dprintk("lockd: release client host %s\n", host->h_name);
296
297 WARN_ON_ONCE(host->h_server);
298
299 if (refcount_dec_and_mutex_lock(&host->h_count, &nlm_host_mutex)) {
300 WARN_ON_ONCE(!list_empty(&host->h_lockowners));
301 WARN_ON_ONCE(!list_empty(&host->h_granted));
302 WARN_ON_ONCE(!list_empty(&host->h_reclaim));
303
304 nlm_destroy_host_locked(host);
305 mutex_unlock(&nlm_host_mutex);
306 }
307 }
308
309 /**
310 * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
311 * @rqstp: incoming NLM request
312 * @hostname: name of client host
313 * @hostname_len: length of client hostname
314 *
315 * Returns an nlm_host structure that matches the [client address,
316 * transport protocol, NLM version, client hostname] of the passed-in
317 * NLM request. If one doesn't already exist in the host cache, a
318 * new handle is created and returned.
319 *
320 * Before possibly creating a new nlm_host, construct a sockaddr
321 * for a specific source address in case the local system has
322 * multiple network addresses. The family of the address in
323 * rq_daddr is guaranteed to be the same as the family of the
324 * address in rq_addr, so it's safe to use the same family for
325 * the source address.
326 */
327 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
328 const char *hostname,
329 const size_t hostname_len)
330 {
331 struct hlist_head *chain;
332 struct nlm_host *host = NULL;
333 struct nsm_handle *nsm = NULL;
334 struct sockaddr *src_sap = svc_daddr(rqstp);
335 size_t src_len = rqstp->rq_daddrlen;
336 struct net *net = SVC_NET(rqstp);
337 struct nlm_lookup_host_info ni = {
338 .server = 1,
339 .sap = svc_addr(rqstp),
340 .salen = rqstp->rq_addrlen,
341 .protocol = rqstp->rq_prot,
342 .version = rqstp->rq_vers,
343 .hostname = hostname,
344 .hostname_len = hostname_len,
345 .net = net,
346 };
347 struct lockd_net *ln = net_generic(net, lockd_net_id);
348
349 dprintk("lockd: %s(host='%.*s', vers=%u, proto=%s)\n", __func__,
350 (int)hostname_len, hostname, rqstp->rq_vers,
351 (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
352
353 mutex_lock(&nlm_host_mutex);
354
355 if (time_after_eq(jiffies, ln->next_gc))
356 nlm_gc_hosts(net);
357
358 chain = &nlm_server_hosts[nlm_hash_address(ni.sap)];
359 hlist_for_each_entry(host, chain, h_hash) {
360 if (host->net != net)
361 continue;
362 if (!rpc_cmp_addr(nlm_addr(host), ni.sap))
363 continue;
364
365 /* Same address. Share an NSM handle if we already have one */
366 if (nsm == NULL)
367 nsm = host->h_nsmhandle;
368
369 if (host->h_proto != ni.protocol)
370 continue;
371 if (host->h_version != ni.version)
372 continue;
373 if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap))
374 continue;
375
376 /* Move to head of hash chain. */
377 hlist_del(&host->h_hash);
378 hlist_add_head(&host->h_hash, chain);
379
380 nlm_get_host(host);
381 dprintk("lockd: %s found host %s (%s)\n",
382 __func__, host->h_name, host->h_addrbuf);
383 goto out;
384 }
385
386 host = nlm_alloc_host(&ni, nsm);
387 if (unlikely(host == NULL))
388 goto out;
389
390 memcpy(nlm_srcaddr(host), src_sap, src_len);
391 host->h_srcaddrlen = src_len;
392 hlist_add_head(&host->h_hash, chain);
393 ln->nrhosts++;
394 nrhosts++;
395
396 refcount_inc(&host->h_count);
397
398 dprintk("lockd: %s created host %s (%s)\n",
399 __func__, host->h_name, host->h_addrbuf);
400
401 out:
402 mutex_unlock(&nlm_host_mutex);
403 return host;
404 }
405
406 /**
407 * nlmsvc_release_host - release server nlm_host
408 * @host: nlm_host to release
409 *
410 * Host is destroyed later in nlm_gc_host().
411 */
412 void nlmsvc_release_host(struct nlm_host *host)
413 {
414 if (host == NULL)
415 return;
416
417 dprintk("lockd: release server host %s\n", host->h_name);
418
419 WARN_ON_ONCE(!host->h_server);
420 refcount_dec(&host->h_count);
421 }
422
423 /*
424 * Create the NLM RPC client for an NLM peer
425 */
426 struct rpc_clnt *
427 nlm_bind_host(struct nlm_host *host)
428 {
429 struct rpc_clnt *clnt;
430
431 dprintk("lockd: nlm_bind_host %s (%s)\n",
432 host->h_name, host->h_addrbuf);
433
434 /* Lock host handle */
435 mutex_lock(&host->h_mutex);
436
437 /* If we've already created an RPC client, check whether
438 * RPC rebind is required
439 */
440 if ((clnt = host->h_rpcclnt) != NULL) {
441 nlm_rebind_host(host);
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 RPC_CLNT_CREATE_REUSEPORT),
463 .cred = host->h_cred,
464 };
465
466 /*
467 * lockd retries server side blocks automatically so we want
468 * those to be soft RPC calls. Client side calls need to be
469 * hard RPC tasks.
470 */
471 if (!host->h_server)
472 args.flags |= RPC_CLNT_CREATE_HARDRTRY;
473 if (host->h_noresvport)
474 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
475 if (host->h_srcaddrlen)
476 args.saddress = nlm_srcaddr(host);
477
478 clnt = rpc_create(&args);
479 if (!IS_ERR(clnt))
480 host->h_rpcclnt = clnt;
481 else {
482 printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
483 clnt = NULL;
484 }
485 }
486
487 mutex_unlock(&host->h_mutex);
488 return clnt;
489 }
490
491 /**
492 * nlm_rebind_host - If needed, force a portmap lookup of the peer's lockd port
493 * @host: NLM host handle for peer
494 *
495 * This is not needed when using a connection-oriented protocol, such as TCP.
496 * The existing autobind mechanism is sufficient to force a rebind when
497 * required, e.g. on connection state transitions.
498 */
499 void
500 nlm_rebind_host(struct nlm_host *host)
501 {
502 if (host->h_proto != IPPROTO_UDP)
503 return;
504
505 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
506 rpc_force_rebind(host->h_rpcclnt);
507 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
508 }
509 }
510
511 /*
512 * Increment NLM host count
513 */
514 struct nlm_host * nlm_get_host(struct nlm_host *host)
515 {
516 if (host) {
517 dprintk("lockd: get host %s\n", host->h_name);
518 refcount_inc(&host->h_count);
519 host->h_expires = jiffies + NLM_HOST_EXPIRE;
520 }
521 return host;
522 }
523
524 static struct nlm_host *next_host_state(struct hlist_head *cache,
525 struct nsm_handle *nsm,
526 const struct nlm_reboot *info)
527 {
528 struct nlm_host *host;
529 struct hlist_head *chain;
530
531 mutex_lock(&nlm_host_mutex);
532 for_each_host(host, chain, cache) {
533 if (host->h_nsmhandle == nsm
534 && host->h_nsmstate != info->state) {
535 host->h_nsmstate = info->state;
536 host->h_state++;
537
538 nlm_get_host(host);
539 mutex_unlock(&nlm_host_mutex);
540 return host;
541 }
542 }
543
544 mutex_unlock(&nlm_host_mutex);
545 return NULL;
546 }
547
548 /**
549 * nlm_host_rebooted - Release all resources held by rebooted host
550 * @net: network namespace
551 * @info: pointer to decoded results of NLM_SM_NOTIFY call
552 *
553 * We were notified that the specified host has rebooted. Release
554 * all resources held by that peer.
555 */
556 void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info)
557 {
558 struct nsm_handle *nsm;
559 struct nlm_host *host;
560
561 nsm = nsm_reboot_lookup(net, info);
562 if (unlikely(nsm == NULL))
563 return;
564
565 /* Mark all hosts tied to this NSM state as having rebooted.
566 * We run the loop repeatedly, because we drop the host table
567 * lock for this.
568 * To avoid processing a host several times, we match the nsmstate.
569 */
570 while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) {
571 nlmsvc_free_host_resources(host);
572 nlmsvc_release_host(host);
573 }
574 while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
575 nlmclnt_recovery(host);
576 nlmclnt_release_host(host);
577 }
578
579 nsm_release(nsm);
580 }
581
582 static void nlm_complain_hosts(struct net *net)
583 {
584 struct hlist_head *chain;
585 struct nlm_host *host;
586
587 if (net) {
588 struct lockd_net *ln = net_generic(net, lockd_net_id);
589
590 if (ln->nrhosts == 0)
591 return;
592 pr_warn("lockd: couldn't shutdown host module for net %x!\n",
593 net->ns.inum);
594 dprintk("lockd: %lu hosts left in net %x:\n", ln->nrhosts,
595 net->ns.inum);
596 } else {
597 if (nrhosts == 0)
598 return;
599 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
600 dprintk("lockd: %lu hosts left:\n", nrhosts);
601 }
602
603 for_each_host(host, chain, nlm_server_hosts) {
604 if (net && host->net != net)
605 continue;
606 dprintk(" %s (cnt %d use %d exp %ld net %x)\n",
607 host->h_name, refcount_read(&host->h_count),
608 host->h_inuse, host->h_expires, host->net->ns.inum);
609 }
610 }
611
612 void
613 nlm_shutdown_hosts_net(struct net *net)
614 {
615 struct hlist_head *chain;
616 struct nlm_host *host;
617
618 mutex_lock(&nlm_host_mutex);
619
620 /* First, make all hosts eligible for gc */
621 dprintk("lockd: nuking all hosts in net %x...\n",
622 net ? net->ns.inum : 0);
623 for_each_host(host, chain, nlm_server_hosts) {
624 if (net && host->net != net)
625 continue;
626 host->h_expires = jiffies - 1;
627 if (host->h_rpcclnt) {
628 rpc_shutdown_client(host->h_rpcclnt);
629 host->h_rpcclnt = NULL;
630 }
631 nlmsvc_free_host_resources(host);
632 }
633
634 /* Then, perform a garbage collection pass */
635 nlm_gc_hosts(net);
636 nlm_complain_hosts(net);
637 mutex_unlock(&nlm_host_mutex);
638 }
639
640 /*
641 * Shut down the hosts module.
642 * Note that this routine is called only at server shutdown time.
643 */
644 void
645 nlm_shutdown_hosts(void)
646 {
647 dprintk("lockd: shutting down host module\n");
648 nlm_shutdown_hosts_net(NULL);
649 }
650
651 /*
652 * Garbage collect any unused NLM hosts.
653 * This GC combines reference counting for async operations with
654 * mark & sweep for resources held by remote clients.
655 */
656 static void
657 nlm_gc_hosts(struct net *net)
658 {
659 struct hlist_head *chain;
660 struct hlist_node *next;
661 struct nlm_host *host;
662
663 dprintk("lockd: host garbage collection for net %x\n",
664 net ? net->ns.inum : 0);
665 for_each_host(host, chain, nlm_server_hosts) {
666 if (net && host->net != net)
667 continue;
668 host->h_inuse = 0;
669 }
670
671 /* Mark all hosts that hold locks, blocks or shares */
672 nlmsvc_mark_resources(net);
673
674 for_each_host_safe(host, next, chain, nlm_server_hosts) {
675 if (net && host->net != net)
676 continue;
677 if (host->h_inuse || time_before(jiffies, host->h_expires)) {
678 dprintk("nlm_gc_hosts skipping %s "
679 "(cnt %d use %d exp %ld net %x)\n",
680 host->h_name, refcount_read(&host->h_count),
681 host->h_inuse, host->h_expires,
682 host->net->ns.inum);
683 continue;
684 }
685 if (refcount_dec_if_one(&host->h_count))
686 nlm_destroy_host_locked(host);
687 }
688
689 if (net) {
690 struct lockd_net *ln = net_generic(net, lockd_net_id);
691
692 ln->next_gc = jiffies + NLM_HOST_COLLECT;
693 }
694 }
695
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