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
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(n: 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(n: addr.s6_addr32[0]) ^
86 __nlm_hash32(n: addr.s6_addr32[1]) ^
87 __nlm_hash32(n: addr.s6_addr32[2]) ^
88 __nlm_hash32(n: 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(r: &nsm->sm_count);
119 else {
120 host = NULL;
121 nsm = nsm_get_handle(net: ni->net, sap: ni->sap, salen: ni->salen,
122 hostname: ni->hostname, hostname_len: ni->hostname_len);
123 if (unlikely(nsm == NULL)) {
124 dprintk("lockd: %s failed; no nsm handle\n",
125 __func__);
126 goto out;
127 }
128 }
129
130 host = kmalloc(size: sizeof(*host), GFP_KERNEL);
131 if (unlikely(host == NULL)) {
132 dprintk("lockd: %s failed; no memory\n", __func__);
133 nsm_release(nsm);
134 goto out;
135 }
136
137 memcpy(nlm_addr(host), ni->sap, ni->salen);
138 host->h_addrlen = ni->salen;
139 rpc_set_port(sap: nlm_addr(host), port: 0);
140 host->h_srcaddrlen = 0;
141
142 host->h_rpcclnt = NULL;
143 host->h_name = nsm->sm_name;
144 host->h_version = ni->version;
145 host->h_proto = ni->protocol;
146 host->h_reclaiming = 0;
147 host->h_server = ni->server;
148 host->h_noresvport = ni->noresvport;
149 host->h_inuse = 0;
150 init_waitqueue_head(&host->h_gracewait);
151 init_rwsem(&host->h_rwsem);
152 host->h_state = 0;
153 host->h_nsmstate = 0;
154 host->h_pidcount = 0;
155 refcount_set(r: &host->h_count, n: 1);
156 mutex_init(&host->h_mutex);
157 host->h_nextrebind = now + NLM_HOST_REBIND;
158 host->h_expires = now + NLM_HOST_EXPIRE;
159 INIT_LIST_HEAD(list: &host->h_lockowners);
160 spin_lock_init(&host->h_lock);
161 INIT_LIST_HEAD(list: &host->h_granted);
162 INIT_LIST_HEAD(list: &host->h_reclaim);
163 host->h_nsmhandle = nsm;
164 host->h_addrbuf = nsm->sm_addrbuf;
165 host->net = ni->net;
166 host->h_cred = get_cred(cred: ni->cred);
167 strscpy(p: host->nodename, q: utsname()->nodename, size: sizeof(host->nodename));
168
169out:
170 return host;
171}
172
173/*
174 * Destroy an nlm_host and free associated resources
175 *
176 * Caller must hold nlm_host_mutex.
177 */
178static void nlm_destroy_host_locked(struct nlm_host *host)
179{
180 struct rpc_clnt *clnt;
181 struct lockd_net *ln = net_generic(net: host->net, id: lockd_net_id);
182
183 dprintk("lockd: destroy host %s\n", host->h_name);
184
185 hlist_del_init(n: &host->h_hash);
186
187 nsm_unmonitor(host);
188 nsm_release(nsm: host->h_nsmhandle);
189
190 clnt = host->h_rpcclnt;
191 if (clnt != NULL)
192 rpc_shutdown_client(clnt);
193 put_cred(cred: host->h_cred);
194 kfree(objp: host);
195
196 ln->nrhosts--;
197 nrhosts--;
198}
199
200/**
201 * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
202 * @sap: network address of server
203 * @salen: length of server address
204 * @protocol: transport protocol to use
205 * @version: NLM protocol version
206 * @hostname: '\0'-terminated hostname of server
207 * @noresvport: 1 if non-privileged port should be used
208 * @net: pointer to net namespace
209 * @cred: pointer to cred
210 *
211 * Returns an nlm_host structure that matches the passed-in
212 * [server address, transport protocol, NLM version, server hostname].
213 * If one doesn't already exist in the host cache, a new handle is
214 * created and returned.
215 */
216struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
217 const size_t salen,
218 const unsigned short protocol,
219 const u32 version,
220 const char *hostname,
221 int noresvport,
222 struct net *net,
223 const struct cred *cred)
224{
225 struct nlm_lookup_host_info ni = {
226 .server = 0,
227 .sap = sap,
228 .salen = salen,
229 .protocol = protocol,
230 .version = version,
231 .hostname = hostname,
232 .hostname_len = strlen(hostname),
233 .noresvport = noresvport,
234 .net = net,
235 .cred = cred,
236 };
237 struct hlist_head *chain;
238 struct nlm_host *host;
239 struct nsm_handle *nsm = NULL;
240 struct lockd_net *ln = net_generic(net, id: lockd_net_id);
241
242 dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
243 (hostname ? hostname : "<none>"), version,
244 (protocol == IPPROTO_UDP ? "udp" : "tcp"));
245
246 mutex_lock(&nlm_host_mutex);
247
248 chain = &nlm_client_hosts[nlm_hash_address(sap)];
249 hlist_for_each_entry(host, chain, h_hash) {
250 if (host->net != net)
251 continue;
252 if (!rpc_cmp_addr(sap1: nlm_addr(host), sap2: sap))
253 continue;
254
255 /* Same address. Share an NSM handle if we already have one */
256 if (nsm == NULL)
257 nsm = host->h_nsmhandle;
258
259 if (host->h_proto != protocol)
260 continue;
261 if (host->h_version != version)
262 continue;
263
264 nlm_get_host(host);
265 dprintk("lockd: %s found host %s (%s)\n", __func__,
266 host->h_name, host->h_addrbuf);
267 goto out;
268 }
269
270 host = nlm_alloc_host(ni: &ni, nsm);
271 if (unlikely(host == NULL))
272 goto out;
273
274 hlist_add_head(n: &host->h_hash, h: chain);
275 ln->nrhosts++;
276 nrhosts++;
277
278 dprintk("lockd: %s created host %s (%s)\n", __func__,
279 host->h_name, host->h_addrbuf);
280
281out:
282 mutex_unlock(lock: &nlm_host_mutex);
283 return host;
284}
285
286/**
287 * nlmclnt_release_host - release client nlm_host
288 * @host: nlm_host to release
289 *
290 */
291void nlmclnt_release_host(struct nlm_host *host)
292{
293 if (host == NULL)
294 return;
295
296 dprintk("lockd: release client host %s\n", host->h_name);
297
298 WARN_ON_ONCE(host->h_server);
299
300 if (refcount_dec_and_mutex_lock(r: &host->h_count, lock: &nlm_host_mutex)) {
301 WARN_ON_ONCE(!list_empty(&host->h_lockowners));
302 WARN_ON_ONCE(!list_empty(&host->h_granted));
303 WARN_ON_ONCE(!list_empty(&host->h_reclaim));
304
305 nlm_destroy_host_locked(host);
306 mutex_unlock(lock: &nlm_host_mutex);
307 }
308}
309
310/**
311 * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
312 * @rqstp: incoming NLM request
313 * @hostname: name of client host
314 * @hostname_len: length of client hostname
315 *
316 * Returns an nlm_host structure that matches the [client address,
317 * transport protocol, NLM version, client hostname] of the passed-in
318 * NLM request. If one doesn't already exist in the host cache, a
319 * new handle is created and returned.
320 *
321 * Before possibly creating a new nlm_host, construct a sockaddr
322 * for a specific source address in case the local system has
323 * multiple network addresses. The family of the address in
324 * rq_daddr is guaranteed to be the same as the family of the
325 * address in rq_addr, so it's safe to use the same family for
326 * the source address.
327 */
328struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
329 const char *hostname,
330 const size_t hostname_len)
331{
332 struct hlist_head *chain;
333 struct nlm_host *host = NULL;
334 struct nsm_handle *nsm = NULL;
335 struct sockaddr *src_sap = svc_daddr(rqst: rqstp);
336 size_t src_len = rqstp->rq_daddrlen;
337 struct net *net = SVC_NET(rqstp);
338 struct nlm_lookup_host_info ni = {
339 .server = 1,
340 .sap = svc_addr(rqst: rqstp),
341 .salen = rqstp->rq_addrlen,
342 .protocol = rqstp->rq_prot,
343 .version = rqstp->rq_vers,
344 .hostname = hostname,
345 .hostname_len = hostname_len,
346 .net = net,
347 };
348 struct lockd_net *ln = net_generic(net, id: lockd_net_id);
349
350 dprintk("lockd: %s(host='%.*s', vers=%u, proto=%s)\n", __func__,
351 (int)hostname_len, hostname, rqstp->rq_vers,
352 (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
353
354 mutex_lock(&nlm_host_mutex);
355
356 if (time_after_eq(jiffies, ln->next_gc))
357 nlm_gc_hosts(net);
358
359 chain = &nlm_server_hosts[nlm_hash_address(sap: ni.sap)];
360 hlist_for_each_entry(host, chain, h_hash) {
361 if (host->net != net)
362 continue;
363 if (!rpc_cmp_addr(sap1: nlm_addr(host), sap2: ni.sap))
364 continue;
365
366 /* Same address. Share an NSM handle if we already have one */
367 if (nsm == NULL)
368 nsm = host->h_nsmhandle;
369
370 if (host->h_proto != ni.protocol)
371 continue;
372 if (host->h_version != ni.version)
373 continue;
374 if (!rpc_cmp_addr(sap1: nlm_srcaddr(host), sap2: src_sap))
375 continue;
376
377 /* Move to head of hash chain. */
378 hlist_del(n: &host->h_hash);
379 hlist_add_head(n: &host->h_hash, h: chain);
380
381 nlm_get_host(host);
382 dprintk("lockd: %s found host %s (%s)\n",
383 __func__, host->h_name, host->h_addrbuf);
384 goto out;
385 }
386
387 host = nlm_alloc_host(ni: &ni, nsm);
388 if (unlikely(host == NULL))
389 goto out;
390
391 memcpy(nlm_srcaddr(host), src_sap, src_len);
392 host->h_srcaddrlen = src_len;
393 hlist_add_head(n: &host->h_hash, h: chain);
394 ln->nrhosts++;
395 nrhosts++;
396
397 refcount_inc(r: &host->h_count);
398
399 dprintk("lockd: %s created host %s (%s)\n",
400 __func__, host->h_name, host->h_addrbuf);
401
402out:
403 mutex_unlock(lock: &nlm_host_mutex);
404 return host;
405}
406
407/**
408 * nlmsvc_release_host - release server nlm_host
409 * @host: nlm_host to release
410 *
411 * Host is destroyed later in nlm_gc_host().
412 */
413void nlmsvc_release_host(struct nlm_host *host)
414{
415 if (host == NULL)
416 return;
417
418 dprintk("lockd: release server host %s\n", host->h_name);
419
420 WARN_ON_ONCE(!host->h_server);
421 refcount_dec(r: &host->h_count);
422}
423
424/*
425 * Create the NLM RPC client for an NLM peer
426 */
427struct rpc_clnt *
428nlm_bind_host(struct nlm_host *host)
429{
430 struct rpc_clnt *clnt;
431
432 dprintk("lockd: nlm_bind_host %s (%s)\n",
433 host->h_name, host->h_addrbuf);
434
435 /* Lock host handle */
436 mutex_lock(&host->h_mutex);
437
438 /* If we've already created an RPC client, check whether
439 * RPC rebind is required
440 */
441 if ((clnt = host->h_rpcclnt) != NULL) {
442 nlm_rebind_host(host);
443 } else {
444 unsigned long increment = nlmsvc_timeout;
445 struct rpc_timeout timeparms = {
446 .to_initval = increment,
447 .to_increment = increment,
448 .to_maxval = increment * 6UL,
449 .to_retries = 5U,
450 };
451 struct rpc_create_args args = {
452 .net = host->net,
453 .protocol = host->h_proto,
454 .address = nlm_addr(host),
455 .addrsize = host->h_addrlen,
456 .timeout = &timeparms,
457 .servername = host->h_name,
458 .program = &nlm_program,
459 .version = host->h_version,
460 .authflavor = RPC_AUTH_UNIX,
461 .flags = (RPC_CLNT_CREATE_NOPING |
462 RPC_CLNT_CREATE_AUTOBIND |
463 RPC_CLNT_CREATE_REUSEPORT),
464 .cred = host->h_cred,
465 };
466
467 /*
468 * lockd retries server side blocks automatically so we want
469 * those to be soft RPC calls. Client side calls need to be
470 * hard RPC tasks.
471 */
472 if (!host->h_server)
473 args.flags |= RPC_CLNT_CREATE_HARDRTRY;
474 if (host->h_noresvport)
475 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
476 if (host->h_srcaddrlen)
477 args.saddress = nlm_srcaddr(host);
478
479 clnt = rpc_create(args: &args);
480 if (!IS_ERR(ptr: clnt))
481 host->h_rpcclnt = clnt;
482 else {
483 printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
484 clnt = NULL;
485 }
486 }
487
488 mutex_unlock(lock: &host->h_mutex);
489 return clnt;
490}
491
492/**
493 * nlm_rebind_host - If needed, force a portmap lookup of the peer's lockd port
494 * @host: NLM host handle for peer
495 *
496 * This is not needed when using a connection-oriented protocol, such as TCP.
497 * The existing autobind mechanism is sufficient to force a rebind when
498 * required, e.g. on connection state transitions.
499 */
500void
501nlm_rebind_host(struct nlm_host *host)
502{
503 if (host->h_proto != IPPROTO_UDP)
504 return;
505
506 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
507 rpc_force_rebind(host->h_rpcclnt);
508 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
509 }
510}
511
512/*
513 * Increment NLM host count
514 */
515struct nlm_host * nlm_get_host(struct nlm_host *host)
516{
517 if (host) {
518 dprintk("lockd: get host %s\n", host->h_name);
519 refcount_inc(r: &host->h_count);
520 host->h_expires = jiffies + NLM_HOST_EXPIRE;
521 }
522 return host;
523}
524
525static struct nlm_host *next_host_state(struct hlist_head *cache,
526 struct nsm_handle *nsm,
527 const struct nlm_reboot *info)
528{
529 struct nlm_host *host;
530 struct hlist_head *chain;
531
532 mutex_lock(&nlm_host_mutex);
533 for_each_host(host, chain, cache) {
534 if (host->h_nsmhandle == nsm
535 && host->h_nsmstate != info->state) {
536 host->h_nsmstate = info->state;
537 host->h_state++;
538
539 nlm_get_host(host);
540 mutex_unlock(lock: &nlm_host_mutex);
541 return host;
542 }
543 }
544
545 mutex_unlock(lock: &nlm_host_mutex);
546 return NULL;
547}
548
549/**
550 * nlm_host_rebooted - Release all resources held by rebooted host
551 * @net: network namespace
552 * @info: pointer to decoded results of NLM_SM_NOTIFY call
553 *
554 * We were notified that the specified host has rebooted. Release
555 * all resources held by that peer.
556 */
557void nlm_host_rebooted(const struct net *net, const struct nlm_reboot *info)
558{
559 struct nsm_handle *nsm;
560 struct nlm_host *host;
561
562 nsm = nsm_reboot_lookup(net, info);
563 if (unlikely(nsm == NULL))
564 return;
565
566 /* Mark all hosts tied to this NSM state as having rebooted.
567 * We run the loop repeatedly, because we drop the host table
568 * lock for this.
569 * To avoid processing a host several times, we match the nsmstate.
570 */
571 while ((host = next_host_state(cache: nlm_server_hosts, nsm, info)) != NULL) {
572 nlmsvc_free_host_resources(host);
573 nlmsvc_release_host(host);
574 }
575 while ((host = next_host_state(cache: nlm_client_hosts, nsm, info)) != NULL) {
576 nlmclnt_recovery(host);
577 nlmclnt_release_host(host);
578 }
579
580 nsm_release(nsm);
581}
582
583static void nlm_complain_hosts(struct net *net)
584{
585 struct hlist_head *chain;
586 struct nlm_host *host;
587
588 if (net) {
589 struct lockd_net *ln = net_generic(net, id: lockd_net_id);
590
591 if (ln->nrhosts == 0)
592 return;
593 pr_warn("lockd: couldn't shutdown host module for net %x!\n",
594 net->ns.inum);
595 dprintk("lockd: %lu hosts left in net %x:\n", ln->nrhosts,
596 net->ns.inum);
597 } else {
598 if (nrhosts == 0)
599 return;
600 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
601 dprintk("lockd: %lu hosts left:\n", nrhosts);
602 }
603
604 for_each_host(host, chain, nlm_server_hosts) {
605 if (net && host->net != net)
606 continue;
607 dprintk(" %s (cnt %d use %d exp %ld net %x)\n",
608 host->h_name, refcount_read(&host->h_count),
609 host->h_inuse, host->h_expires, host->net->ns.inum);
610 }
611}
612
613void
614nlm_shutdown_hosts_net(struct net *net)
615{
616 struct hlist_head *chain;
617 struct nlm_host *host;
618
619 mutex_lock(&nlm_host_mutex);
620
621 /* First, make all hosts eligible for gc */
622 dprintk("lockd: nuking all hosts in net %x...\n",
623 net ? net->ns.inum : 0);
624 for_each_host(host, chain, nlm_server_hosts) {
625 if (net && host->net != net)
626 continue;
627 host->h_expires = jiffies - 1;
628 if (host->h_rpcclnt) {
629 rpc_shutdown_client(host->h_rpcclnt);
630 host->h_rpcclnt = NULL;
631 }
632 nlmsvc_free_host_resources(host);
633 }
634
635 /* Then, perform a garbage collection pass */
636 nlm_gc_hosts(net);
637 nlm_complain_hosts(net);
638 mutex_unlock(lock: &nlm_host_mutex);
639}
640
641/*
642 * Shut down the hosts module.
643 * Note that this routine is called only at server shutdown time.
644 */
645void
646nlm_shutdown_hosts(void)
647{
648 dprintk("lockd: shutting down host module\n");
649 nlm_shutdown_hosts_net(NULL);
650}
651
652/*
653 * Garbage collect any unused NLM hosts.
654 * This GC combines reference counting for async operations with
655 * mark & sweep for resources held by remote clients.
656 */
657static void
658nlm_gc_hosts(struct net *net)
659{
660 struct hlist_head *chain;
661 struct hlist_node *next;
662 struct nlm_host *host;
663
664 dprintk("lockd: host garbage collection for net %x\n",
665 net ? net->ns.inum : 0);
666 for_each_host(host, chain, nlm_server_hosts) {
667 if (net && host->net != net)
668 continue;
669 host->h_inuse = 0;
670 }
671
672 /* Mark all hosts that hold locks, blocks or shares */
673 nlmsvc_mark_resources(net);
674
675 for_each_host_safe(host, next, chain, nlm_server_hosts) {
676 if (net && host->net != net)
677 continue;
678 if (host->h_inuse || time_before(jiffies, host->h_expires)) {
679 dprintk("nlm_gc_hosts skipping %s "
680 "(cnt %d use %d exp %ld net %x)\n",
681 host->h_name, refcount_read(&host->h_count),
682 host->h_inuse, host->h_expires,
683 host->net->ns.inum);
684 continue;
685 }
686 if (refcount_dec_if_one(r: &host->h_count))
687 nlm_destroy_host_locked(host);
688 }
689
690 if (net) {
691 struct lockd_net *ln = net_generic(net, id: lockd_net_id);
692
693 ln->next_gc = jiffies + NLM_HOST_COLLECT;
694 }
695}
696

source code of linux/fs/lockd/host.c