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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 <[email protected]>
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/mutex.h>
20
21#include <linux/sunrpc/svc_xprt.h>
22
23#include <net/ipv6.h>
24
25#include "lockd.h"
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
34static struct hlist_head nlm_server_hosts[NLM_HOST_NRHASH];
35static 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
48static unsigned long nrhosts;
49static DEFINE_MUTEX(nlm_host_mutex);
50
51static void nlm_gc_hosts(struct net *net);
52
53struct 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 */
69static 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
75static 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
81static 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
91static 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 */
111static 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_obj(*host);
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
168out:
169 return host;
170}
171
172/*
173 * Destroy an nlm_host and free associated resources
174 *
175 * Caller must hold nlm_host_mutex.
176 */
177static 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 */
215struct 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
280out:
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 */
290void 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/* Callback for rpc_cancel_tasks() - matches all tasks for cancellation */
310static bool nlmclnt_match_all(const struct rpc_task *task, const void *data)
311{
312 return true;
313}
314
315/**
316 * nlmclnt_shutdown_rpc_clnt - safely shut down NLM client RPC operations
317 * @host: nlm_host to shut down
318 *
319 * Cancels outstanding RPC tasks and marks the client as shut down.
320 * Synchronizes with nlmclnt_release_host() via nlm_host_mutex to prevent
321 * races between shutdown and host destruction. Safe to call if h_rpcclnt
322 * is NULL or already shut down.
323 */
324void nlmclnt_shutdown_rpc_clnt(struct nlm_host *host)
325{
326 struct rpc_clnt *clnt;
327
328 mutex_lock(&nlm_host_mutex);
329 clnt = host->h_rpcclnt;
330 if (clnt) {
331 clnt->cl_shutdown = 1;
332 rpc_cancel_tasks(clnt, -EIO, nlmclnt_match_all, NULL);
333 }
334 mutex_unlock(&nlm_host_mutex);
335}
336EXPORT_SYMBOL_GPL(nlmclnt_shutdown_rpc_clnt);
337
338/**
339 * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
340 * @rqstp: incoming NLM request
341 * @hostname: name of client host
342 * @hostname_len: length of client hostname
343 *
344 * Returns an nlm_host structure that matches the [client address,
345 * transport protocol, NLM version, client hostname] of the passed-in
346 * NLM request. If one doesn't already exist in the host cache, a
347 * new handle is created and returned.
348 *
349 * Before possibly creating a new nlm_host, construct a sockaddr
350 * for a specific source address in case the local system has
351 * multiple network addresses. The family of the address in
352 * rq_daddr is guaranteed to be the same as the family of the
353 * address in rq_addr, so it's safe to use the same family for
354 * the source address.
355 */
356struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
357 const char *hostname,
358 const size_t hostname_len)
359{
360 struct hlist_head *chain;
361 struct nlm_host *host = NULL;
362 struct nsm_handle *nsm = NULL;
363 struct sockaddr *src_sap = svc_daddr(rqstp);
364 size_t src_len = rqstp->rq_daddrlen;
365 struct net *net = SVC_NET(rqstp);
366 struct nlm_lookup_host_info ni = {
367 .server = 1,
368 .sap = svc_addr(rqstp),
369 .salen = rqstp->rq_addrlen,
370 .protocol = rqstp->rq_prot,
371 .version = rqstp->rq_vers,
372 .hostname = hostname,
373 .hostname_len = hostname_len,
374 .net = net,
375 };
376 struct lockd_net *ln = net_generic(net, lockd_net_id);
377
378 dprintk("lockd: %s(host='%.*s', vers=%u, proto=%s)\n", __func__,
379 (int)hostname_len, hostname, rqstp->rq_vers,
380 (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
381
382 mutex_lock(&nlm_host_mutex);
383
384 if (time_after_eq(jiffies, ln->next_gc))
385 nlm_gc_hosts(net);
386
387 chain = &nlm_server_hosts[nlm_hash_address(ni.sap)];
388 hlist_for_each_entry(host, chain, h_hash) {
389 if (host->net != net)
390 continue;
391 if (!rpc_cmp_addr(nlm_addr(host), ni.sap))
392 continue;
393
394 /* Same address. Share an NSM handle if we already have one */
395 if (nsm == NULL)
396 nsm = host->h_nsmhandle;
397
398 if (host->h_proto != ni.protocol)
399 continue;
400 if (host->h_version != ni.version)
401 continue;
402 if (!rpc_cmp_addr(nlm_srcaddr(host), src_sap))
403 continue;
404
405 /* Move to head of hash chain. */
406 hlist_del(&host->h_hash);
407 hlist_add_head(&host->h_hash, chain);
408
409 nlm_get_host(host);
410 dprintk("lockd: %s found host %s (%s)\n",
411 __func__, host->h_name, host->h_addrbuf);
412 goto out;
413 }
414
415 host = nlm_alloc_host(&ni, nsm);
416 if (unlikely(host == NULL))
417 goto out;
418
419 memcpy(nlm_srcaddr(host), src_sap, src_len);
420 host->h_srcaddrlen = src_len;
421 hlist_add_head(&host->h_hash, chain);
422 ln->nrhosts++;
423 nrhosts++;
424
425 refcount_inc(&host->h_count);
426
427 dprintk("lockd: %s created host %s (%s)\n",
428 __func__, host->h_name, host->h_addrbuf);
429
430out:
431 mutex_unlock(&nlm_host_mutex);
432 return host;
433}
434
435/**
436 * nlmsvc_release_host - release server nlm_host
437 * @host: nlm_host to release
438 *
439 * Host is destroyed later in nlm_gc_host().
440 */
441void nlmsvc_release_host(struct nlm_host *host)
442{
443 if (host == NULL)
444 return;
445
446 dprintk("lockd: release server host %s\n", host->h_name);
447
448 WARN_ON_ONCE(!host->h_server);
449 refcount_dec(&host->h_count);
450}
451
452/*
453 * Create the NLM RPC client for an NLM peer
454 */
455struct rpc_clnt *
456nlm_bind_host(struct nlm_host *host)
457{
458 struct rpc_clnt *clnt;
459
460 dprintk("lockd: nlm_bind_host %s (%s)\n",
461 host->h_name, host->h_addrbuf);
462
463 /* Lock host handle */
464 mutex_lock(&host->h_mutex);
465
466 /* If we've already created an RPC client, check whether
467 * RPC rebind is required
468 */
469 if ((clnt = host->h_rpcclnt) != NULL) {
470 nlm_rebind_host(host);
471 } else {
472 unsigned long increment = nlm_timeout * HZ;
473 struct rpc_timeout timeparms = {
474 .to_initval = increment,
475 .to_increment = increment,
476 .to_maxval = increment * 6UL,
477 .to_retries = 5U,
478 };
479 struct rpc_create_args args = {
480 .net = host->net,
481 .protocol = host->h_proto,
482 .address = nlm_addr(host),
483 .addrsize = host->h_addrlen,
484 .timeout = &timeparms,
485 .servername = host->h_name,
486 .program = &nlm_program,
487 .version = host->h_version,
488 .authflavor = RPC_AUTH_UNIX,
489 .flags = (RPC_CLNT_CREATE_NOPING |
490 RPC_CLNT_CREATE_AUTOBIND |
491 RPC_CLNT_CREATE_REUSEPORT),
492 .cred = host->h_cred,
493 };
494
495 /*
496 * lockd retries server side blocks automatically so we want
497 * those to be soft RPC calls. Client side calls need to be
498 * hard RPC tasks.
499 */
500 if (!host->h_server)
501 args.flags |= RPC_CLNT_CREATE_HARDRTRY;
502 if (host->h_noresvport)
503 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
504 if (host->h_srcaddrlen)
505 args.saddress = nlm_srcaddr(host);
506
507 clnt = rpc_create(&args);
508 if (!IS_ERR(clnt))
509 host->h_rpcclnt = clnt;
510 else {
511 printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
512 clnt = NULL;
513 }
514 }
515
516 mutex_unlock(&host->h_mutex);
517 return clnt;
518}
519
520/**
521 * nlm_rebind_host - If needed, force a portmap lookup of the peer's lockd port
522 * @host: NLM host handle for peer
523 *
524 * This is not needed when using a connection-oriented protocol, such as TCP.
525 * The existing autobind mechanism is sufficient to force a rebind when
526 * required, e.g. on connection state transitions.
527 */
528void
529nlm_rebind_host(struct nlm_host *host)
530{
531 if (host->h_proto != IPPROTO_UDP)
532 return;
533
534 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
535 rpc_force_rebind(host->h_rpcclnt);
536 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
537 }
538}
539
540/*
541 * Increment NLM host count
542 */
543struct nlm_host * nlm_get_host(struct nlm_host *host)
544{
545 if (host) {
546 dprintk("lockd: get host %s\n", host->h_name);
547 refcount_inc(&host->h_count);
548 host->h_expires = jiffies + NLM_HOST_EXPIRE;
549 }
550 return host;
551}
552
553static struct nlm_host *next_host_state(struct hlist_head *cache,
554 struct nsm_handle *nsm,
555 const struct lockd_reboot *info)
556{
557 struct nlm_host *host;
558 struct hlist_head *chain;
559
560 mutex_lock(&nlm_host_mutex);
561 for_each_host(host, chain, cache) {
562 if (host->h_nsmhandle == nsm
563 && host->h_nsmstate != info->state) {
564 host->h_nsmstate = info->state;
565 host->h_state++;
566
567 nlm_get_host(host);
568 mutex_unlock(&nlm_host_mutex);
569 return host;
570 }
571 }
572
573 mutex_unlock(&nlm_host_mutex);
574 return NULL;
575}
576
577/**
578 * nlm_host_rebooted - Release all resources held by rebooted host
579 * @net: network namespace
580 * @info: pointer to decoded results of NLM_SM_NOTIFY call
581 *
582 * We were notified that the specified host has rebooted. Release
583 * all resources held by that peer.
584 */
585void nlm_host_rebooted(const struct net *net, const struct lockd_reboot *info)
586{
587 struct nsm_handle *nsm;
588 struct nlm_host *host;
589
590 nsm = nsm_reboot_lookup(net, info);
591 if (unlikely(nsm == NULL))
592 return;
593
594 /* Mark all hosts tied to this NSM state as having rebooted.
595 * We run the loop repeatedly, because we drop the host table
596 * lock for this.
597 * To avoid processing a host several times, we match the nsmstate.
598 */
599 while ((host = next_host_state(nlm_server_hosts, nsm, info)) != NULL) {
600 nlmsvc_free_host_resources(host);
601 nlmsvc_release_host(host);
602 }
603 while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
604 nlmclnt_recovery(host);
605 nlmclnt_release_host(host);
606 }
607
608 nsm_release(nsm);
609}
610
611static void nlm_complain_hosts(struct net *net)
612{
613 struct hlist_head *chain;
614 struct nlm_host *host;
615
616 if (net) {
617 struct lockd_net *ln = net_generic(net, lockd_net_id);
618
619 if (ln->nrhosts == 0)
620 return;
621 pr_warn("lockd: couldn't shutdown host module for net %x!\n",
622 net->ns.inum);
623 dprintk("lockd: %lu hosts left in net %x:\n", ln->nrhosts,
624 net->ns.inum);
625 } else {
626 if (nrhosts == 0)
627 return;
628 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
629 dprintk("lockd: %lu hosts left:\n", nrhosts);
630 }
631
632 for_each_host(host, chain, nlm_server_hosts) {
633 if (net && host->net != net)
634 continue;
635 dprintk(" %s (cnt %d use %d exp %ld net %x)\n",
636 host->h_name, refcount_read(&host->h_count),
637 host->h_inuse, host->h_expires, host->net->ns.inum);
638 }
639}
640
641void
642nlm_shutdown_hosts_net(struct net *net)
643{
644 struct hlist_head *chain;
645 struct nlm_host *host;
646
647 mutex_lock(&nlm_host_mutex);
648
649 /* First, make all hosts eligible for gc */
650 dprintk("lockd: nuking all hosts in net %x...\n",
651 net ? net->ns.inum : 0);
652 for_each_host(host, chain, nlm_server_hosts) {
653 if (net && host->net != net)
654 continue;
655 host->h_expires = jiffies - 1;
656 if (host->h_rpcclnt) {
657 rpc_shutdown_client(host->h_rpcclnt);
658 host->h_rpcclnt = NULL;
659 }
660 nlmsvc_free_host_resources(host);
661 }
662
663 /* Then, perform a garbage collection pass */
664 nlm_gc_hosts(net);
665 nlm_complain_hosts(net);
666 mutex_unlock(&nlm_host_mutex);
667}
668
669/*
670 * Shut down the hosts module.
671 * Note that this routine is called only at server shutdown time.
672 */
673void
674nlm_shutdown_hosts(void)
675{
676 dprintk("lockd: shutting down host module\n");
677 nlm_shutdown_hosts_net(NULL);
678}
679
680/*
681 * Garbage collect any unused NLM hosts.
682 * This GC combines reference counting for async operations with
683 * mark & sweep for resources held by remote clients.
684 */
685static void
686nlm_gc_hosts(struct net *net)
687{
688 struct hlist_head *chain;
689 struct hlist_node *next;
690 struct nlm_host *host;
691
692 dprintk("lockd: host garbage collection for net %x\n",
693 net ? net->ns.inum : 0);
694 for_each_host(host, chain, nlm_server_hosts) {
695 if (net && host->net != net)
696 continue;
697 host->h_inuse = 0;
698 }
699
700 /* Mark all hosts that hold locks, blocks or shares */
701 nlmsvc_mark_resources(net);
702
703 for_each_host_safe(host, next, chain, nlm_server_hosts) {
704 if (net && host->net != net)
705 continue;
706 if (host->h_inuse || time_before(jiffies, host->h_expires)) {
707 dprintk("nlm_gc_hosts skipping %s "
708 "(cnt %d use %d exp %ld net %x)\n",
709 host->h_name, refcount_read(&host->h_count),
710 host->h_inuse, host->h_expires,
711 host->net->ns.inum);
712 continue;
713 }
714 if (refcount_dec_if_one(&host->h_count))
715 nlm_destroy_host_locked(host);
716 }
717
718 if (net) {
719 struct lockd_net *ln = net_generic(net, lockd_net_id);
720
721 ln->next_gc = jiffies + NLM_HOST_COLLECT;
722 }
723}