aboutsummaryrefslogtreecommitdiffstats
path: root/fs/lockd/mon.c
blob: 6d5d4a4169e5ae472dcf2ad43e46e0495c20fb05 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
/*
 * linux/fs/lockd/mon.c
 *
 * The kernel statd client.
 *
 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
 */

#include <linux/types.h>
#include <linux/utsname.h>
#include <linux/kernel.h>
#include <linux/ktime.h>

#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/xprtsock.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>

#include <asm/unaligned.h>

#define NLMDBG_FACILITY		NLMDBG_MONITOR
#define NSM_PROGRAM		100024
#define NSM_VERSION		1

enum {
	NSMPROC_NULL,
	NSMPROC_STAT,
	NSMPROC_MON,
	NSMPROC_UNMON,
	NSMPROC_UNMON_ALL,
	NSMPROC_SIMU_CRASH,
	NSMPROC_NOTIFY,
};

struct nsm_args {
	struct nsm_private	*priv;
	u32			prog;		/* RPC callback info */
	u32			vers;
	u32			proc;

	char			*mon_name;
};

struct nsm_res {
	u32			status;
	u32			state;
};

static struct rpc_program	nsm_program;
static				LIST_HEAD(nsm_handles);
static				DEFINE_SPINLOCK(nsm_lock);

/*
 * Local NSM state
 */
int	__read_mostly		nsm_local_state;
int	__read_mostly		nsm_use_hostnames;

static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
{
	return (struct sockaddr *)&nsm->sm_addr;
}

static void nsm_display_ipv4_address(const struct sockaddr *sap, char *buf,
				     const size_t len)
{
	const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
	snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr);
}

static void nsm_display_ipv6_address(const struct sockaddr *sap, char *buf,
				     const size_t len)
{
	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;

	if (ipv6_addr_v4mapped(&sin6->sin6_addr))
		snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]);
	else if (sin6->sin6_scope_id != 0)
		snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr,
				sin6->sin6_scope_id);
	else
		snprintf(buf, len, "%pI6", &sin6->sin6_addr);
}

static void nsm_display_address(const struct sockaddr *sap,
				char *buf, const size_t len)
{
	switch (sap->sa_family) {
	case AF_INET:
		nsm_display_ipv4_address(sap, buf, len);
		break;
	case AF_INET6:
		nsm_display_ipv6_address(sap, buf, len);
		break;
	default:
		snprintf(buf, len, "unsupported address family");
		break;
	}
}

static struct rpc_clnt *nsm_create(void)
{
	struct sockaddr_in sin = {
		.sin_family		= AF_INET,
		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
	};
	struct rpc_create_args args = {
		.protocol		= XPRT_TRANSPORT_UDP,
		.address		= (struct sockaddr *)&sin,
		.addrsize		= sizeof(sin),
		.servername		= "rpc.statd",
		.program		= &nsm_program,
		.version		= NSM_VERSION,
		.authflavor		= RPC_AUTH_NULL,
	};

	return rpc_create(&args);
}

static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res)
{
	struct rpc_clnt	*clnt;
	int		status;
	struct nsm_args args = {
		.priv		= &nsm->sm_priv,
		.prog		= NLM_PROGRAM,
		.vers		= 3,
		.proc		= NLMPROC_NSM_NOTIFY,
		.mon_name	= nsm->sm_mon_name,
	};
	struct rpc_message msg = {
		.rpc_argp	= &args,
		.rpc_resp	= res,
	};

	clnt = nsm_create();
	if (IS_ERR(clnt)) {
		status = PTR_ERR(clnt);
		dprintk("lockd: failed to create NSM upcall transport, "
				"status=%d\n", status);
		goto out;
	}

	memset(res, 0, sizeof(*res));

	msg.rpc_proc = &clnt->cl_procinfo[proc];
	status = rpc_call_sync(clnt, &msg, 0);
	if (status < 0)
		dprintk("lockd: NSM upcall RPC failed, status=%d\n",
				status);
	else
		status = 0;
	rpc_shutdown_client(clnt);
 out:
	return status;
}

/**
 * nsm_monitor - Notify a peer in case we reboot
 * @host: pointer to nlm_host of peer to notify
 *
 * If this peer is not already monitored, this function sends an
 * upcall to the local rpc.statd to record the name/address of
 * the peer to notify in case we reboot.
 *
 * Returns zero if the peer is monitored by the local rpc.statd;
 * otherwise a negative errno value is returned.
 */
int nsm_monitor(const struct nlm_host *host)
{
	struct nsm_handle *nsm = host->h_nsmhandle;
	struct nsm_res	res;
	int		status;

	dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);

	if (nsm->sm_monitored)
		return 0;

	/*
	 * Choose whether to record the caller_name or IP address of
	 * this peer in the local rpc.statd's database.
	 */
	nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;

	status = nsm_mon_unmon(nsm, NSMPROC_MON, &res);
	if (res.status != 0)
		status = -EIO;
	if (status < 0)
		printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name);
	else
		nsm->sm_monitored = 1;
	return status;
}

/**
 * nsm_unmonitor - Unregister peer notification
 * @host: pointer to nlm_host of peer to stop monitoring
 *
 * If this peer is monitored, this function sends an upcall to
 * tell the local rpc.statd not to send this peer a notification
 * when we reboot.
 */
void nsm_unmonitor(const struct nlm_host *host)
{
	struct nsm_handle *nsm = host->h_nsmhandle;
	struct nsm_res	res;
	int status;

	if (atomic_read(&nsm->sm_count) == 1
	 && nsm->sm_monitored && !nsm->sm_sticky) {
		dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);

		status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res);
		if (res.status != 0)
			status = -EIO;
		if (status < 0)
			printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
					nsm->sm_name);
		else
			nsm->sm_monitored = 0;
	}
}

static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
					      const size_t len)
{
	struct nsm_handle *nsm;

	list_for_each_entry(nsm, &nsm_handles, sm_link)
		if (strlen(nsm->sm_name) == len &&
		    memcmp(nsm->sm_name, hostname, len) == 0)
			return nsm;
	return NULL;
}

static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
{
	struct nsm_handle *nsm;

	list_for_each_entry(nsm, &nsm_handles, sm_link)
		if (nlm_cmp_addr(nsm_addr(nsm), sap))
			return nsm;
	return NULL;
}

static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
{
	struct nsm_handle *nsm;

	list_for_each_entry(nsm, &nsm_handles, sm_link)
		if (memcmp(nsm->sm_priv.data, priv->data,
					sizeof(priv->data)) == 0)
			return nsm;
	return NULL;
}

/*
 * Construct a unique cookie to match this nsm_handle to this monitored
 * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
 * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
 * requests.
 *
 * The NSM protocol requires that these cookies be unique while the
 * system is running.  We prefer a stronger requirement of making them
 * unique across reboots.  If user space bugs cause a stale cookie to
 * be sent to the kernel, it could cause the wrong host to lose its
 * lock state if cookies were not unique across reboots.
 *
 * The cookies are exposed only to local user space via loopback.  They
 * do not appear on the physical network.  If we want greater security
 * for some reason, nsm_init_private() could perform a one-way hash to
 * obscure the contents of the cookie.
 */
static void nsm_init_private(struct nsm_handle *nsm)
{
	u64 *p = (u64 *)&nsm->sm_priv.data;
	struct timespec ts;
	s64 ns;

	ktime_get_ts(&ts);
	ns = timespec_to_ns(&ts);
	put_unaligned(ns, p);
	put_unaligned((unsigned long)nsm, p + 1);
}

static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
					    const size_t salen,
					    const char *hostname,
					    const size_t hostname_len)
{
	struct nsm_handle *new;

	new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
	if (unlikely(new == NULL))
		return NULL;

	atomic_set(&new->sm_count, 1);
	new->sm_name = (char *)(new + 1);
	memcpy(nsm_addr(new), sap, salen);
	new->sm_addrlen = salen;
	nsm_init_private(new);
	nsm_display_address((const struct sockaddr *)&new->sm_addr,
				new->sm_addrbuf, sizeof(new->sm_addrbuf));
	memcpy(new->sm_name, hostname, hostname_len);
	new->sm_name[hostname_len] = '\0';

	return new;
}

/**
 * nsm_get_handle - Find or create a cached nsm_handle
 * @sap: pointer to socket address of handle to find
 * @salen: length of socket address
 * @hostname: pointer to C string containing hostname to find
 * @hostname_len: length of C string
 *
 * Behavior is modulated by the global nsm_use_hostnames variable.
 *
 * Returns a cached nsm_handle after bumping its ref count, or
 * returns a fresh nsm_handle if a handle that matches @sap and/or
 * @hostname cannot be found in the handle cache.  Returns NULL if
 * an error occurs.
 */
struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
				  const size_t salen, const char *hostname,
				  const size_t hostname_len)
{
	struct nsm_handle *cached, *new = NULL;

	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
		if (printk_ratelimit()) {
			printk(KERN_WARNING "Invalid hostname \"%.*s\" "
					    "in NFS lock request\n",
				(int)hostname_len, hostname);
		}
		return NULL;
	}

retry:
	spin_lock(&nsm_lock);

	if (nsm_use_hostnames && hostname != NULL)
		cached = nsm_lookup_hostname(hostname, hostname_len);
	else
		cached = nsm_lookup_addr(sap);

	if (cached != NULL) {
		atomic_inc(&cached->sm_count);
		spin_unlock(&nsm_lock);
		kfree(new);
		dprintk("lockd: found nsm_handle for %s (%s), "
				"cnt %d\n", cached->sm_name,
				cached->sm_addrbuf,
				atomic_read(&cached->sm_count));
		return cached;
	}

	if (new != NULL) {
		list_add(&new->sm_link, &nsm_handles);
		spin_unlock(&nsm_lock);
		dprintk("lockd: created nsm_handle for %s (%s)\n",
				new->sm_name, new->sm_addrbuf);
		return new;
	}

	spin_unlock(&nsm_lock);

	new = nsm_create_handle(sap, salen, hostname, hostname_len);
	if (unlikely(new == NULL))
		return NULL;
	goto retry;
}

/**
 * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
 * @info: pointer to NLMPROC_SM_NOTIFY arguments
 *
 * Returns a matching nsm_handle if found in the nsm cache; the returned
 * nsm_handle's reference count is bumped and sm_monitored is cleared.
 * Otherwise returns NULL if some error occurred.
 */
struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)
{
	struct nsm_handle *cached;

	spin_lock(&nsm_lock);

	cached = nsm_lookup_priv(&info->priv);
	if (unlikely(cached == NULL)) {
		spin_unlock(&nsm_lock);
		dprintk("lockd: never saw rebooted peer '%.*s' before\n",
				info->len, info->mon);
		return cached;
	}

	atomic_inc(&cached->sm_count);
	spin_unlock(&nsm_lock);

	/*
	 * During subsequent lock activity, force a fresh
	 * notification to be set up for this host.
	 */
	cached->sm_monitored = 0;

	dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
			cached->sm_name, cached->sm_addrbuf,
			atomic_read(&cached->sm_count));
	return cached;
}

/**
 * nsm_release - Release an NSM handle
 * @nsm: pointer to handle to be released
 *
 */
void nsm_release(struct nsm_handle *nsm)
{
	if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
		list_del(&nsm->sm_link);
		spin_unlock(&nsm_lock);
		dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
				nsm->sm_name, nsm->sm_addrbuf);
		kfree(nsm);
	}
}

/*
 * XDR functions for NSM.
 *
 * See http://www.opengroup.org/ for details on the Network
 * Status Monitor wire protocol.
 */

static int encode_nsm_string(struct xdr_stream *xdr, const char *string)
{
	const u32 len = strlen(string);
	__be32 *p;

	if (unlikely(len > SM_MAXSTRLEN))
		return -EIO;
	p = xdr_reserve_space(xdr, sizeof(u32) + len);
	if (unlikely(p == NULL))
		return -EIO;
	xdr_encode_opaque(p, string, len);
	return 0;
}

/*
 * "mon_name" specifies the host to be monitored.
 */
static int encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
{
	return encode_nsm_string(xdr, argp->mon_name);
}

/*
 * The "my_id" argument specifies the hostname and RPC procedure
 * to be called when the status manager receives notification
 * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
 * has changed.
 */
static int encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
{
	int status;
	__be32 *p;

	status = encode_nsm_string(xdr, utsname()->nodename);
	if (unlikely(status != 0))
		return status;
	p = xdr_reserve_space(xdr, 3 * sizeof(u32));
	if (unlikely(p == NULL))
		return -EIO;
	*p++ = htonl(argp->prog);
	*p++ = htonl(argp->vers);
	*p++ = htonl(argp->proc);
	return 0;
}

/*
 * The "mon_id" argument specifies the non-private arguments
 * of an NSMPROC_MON or NSMPROC_UNMON call.
 */
static int encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
{
	int status;

	status = encode_mon_name(xdr, argp);
	if (unlikely(status != 0))
		return status;
	return encode_my_id(xdr, argp);
}

/*
 * The "priv" argument may contain private information required
 * by the NSMPROC_MON call. This information will be supplied in the
 * NLMPROC_SM_NOTIFY call.
 */
static int encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
{
	__be32 *p;

	p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
	if (unlikely(p == NULL))
		return -EIO;
	xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
	return 0;
}

static int xdr_enc_mon(struct rpc_rqst *req, __be32 *p,
		       const struct nsm_args *argp)
{
	struct xdr_stream xdr;
	int status;

	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
	status = encode_mon_id(&xdr, argp);
	if (unlikely(status))
		return status;
	return encode_priv(&xdr, argp);
}

static int xdr_enc_unmon(struct rpc_rqst *req, __be32 *p,
			 const struct nsm_args *argp)
{
	struct xdr_stream xdr;

	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
	return encode_mon_id(&xdr, argp);
}

static int xdr_dec_stat_res(struct rpc_rqst *rqstp, __be32 *p,
			    struct nsm_res *resp)
{
	struct xdr_stream xdr;

	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
	p = xdr_inline_decode(&xdr, 2 * sizeof(u32));
	if (unlikely(p == NULL))
		return -EIO;
	resp->status = ntohl(*p++);
	resp->state = ntohl(*p);

	dprintk("lockd: xdr_dec_stat_res status %d state %d\n",
			resp->status, resp->state);
	return 0;
}

static int xdr_dec_stat(struct rpc_rqst *rqstp, __be32 *p,
			struct nsm_res *resp)
{
	struct xdr_stream xdr;

	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
	p = xdr_inline_decode(&xdr, sizeof(u32));
	if (unlikely(p == NULL))
		return -EIO;
	resp->state = ntohl(*p);

	dprintk("lockd: xdr_dec_stat state %d\n", resp->state);
	return 0;
}

#define SM_my_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
#define SM_my_id_sz	(SM_my_name_sz+3)
#define SM_mon_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
#define SM_mon_id_sz	(SM_mon_name_sz+SM_my_id_sz)
#define SM_priv_sz	(XDR_QUADLEN(SM_PRIV_SIZE))
#define SM_mon_sz	(SM_mon_id_sz+SM_priv_sz)
#define SM_monres_sz	2
#define SM_unmonres_sz	1

static struct rpc_procinfo	nsm_procedures[] = {
[NSMPROC_MON] = {
		.p_proc		= NSMPROC_MON,
		.p_encode	= (kxdrproc_t)xdr_enc_mon,
		.p_decode	= (kxdrproc_t)xdr_dec_stat_res,
		.p_arglen	= SM_mon_sz,
		.p_replen	= SM_monres_sz,
		.p_statidx	= NSMPROC_MON,
		.p_name		= "MONITOR",
	},
[NSMPROC_UNMON] = {
		.p_proc		= NSMPROC_UNMON,
		.p_encode	= (kxdrproc_t)xdr_enc_unmon,
		.p_decode	= (kxdrproc_t)xdr_dec_stat,
		.p_arglen	= SM_mon_id_sz,
		.p_replen	= SM_unmonres_sz,
		.p_statidx	= NSMPROC_UNMON,
		.p_name		= "UNMONITOR",
	},
};

static struct rpc_version	nsm_version1 = {
		.number		= 1,
		.nrprocs	= ARRAY_SIZE(nsm_procedures),
		.procs		= nsm_procedures
};

static struct rpc_version *	nsm_version[] = {
	[1] = &nsm_version1,
};

static struct rpc_stat		nsm_stats;

static struct rpc_program	nsm_program = {
		.name		= "statd",
		.number		= NSM_PROGRAM,
		.nrvers		= ARRAY_SIZE(nsm_version),
		.version	= nsm_version,
		.stats		= &nsm_stats
};