blob: e87d500ad95aad74ae48e76896e29d8f02df7778 [file] [log] [blame]
Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Trond Myklebuste571cbf2009-08-19 18:12:27 -04002/*
3 * linux/fs/nfs/dns_resolve.c
4 *
5 * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
6 *
7 * Resolves DNS hostnames into valid ip addresses
8 */
9
Bryan Schumakerc2e81392010-08-11 09:37:53 +010010#ifdef CONFIG_NFS_USE_KERNEL_DNS
11
Bryan Schumaker89d77c82012-07-30 16:05:25 -040012#include <linux/module.h>
Bryan Schumakerc2e81392010-08-11 09:37:53 +010013#include <linux/sunrpc/clnt.h>
Jeff Layton59766872013-02-04 12:50:00 -050014#include <linux/sunrpc/addr.h>
Bryan Schumakerc2e81392010-08-11 09:37:53 +010015#include <linux/dns_resolver.h>
Trond Myklebust17280172012-03-11 13:11:00 -040016#include "dns_resolve.h"
Bryan Schumakerc2e81392010-08-11 09:37:53 +010017
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +030018ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
Bryan Schumakerc2e81392010-08-11 09:37:53 +010019 struct sockaddr *sa, size_t salen)
20{
21 ssize_t ret;
22 char *ip_addr = NULL;
23 int ip_len;
24
David Howellsa58946c2019-06-26 21:02:33 +010025 ip_len = dns_query(net, NULL, name, namelen, NULL, &ip_addr, NULL,
26 false);
Bryan Schumakerc2e81392010-08-11 09:37:53 +010027 if (ip_len > 0)
Stanislav Kinsburskybc224f52012-01-26 15:11:33 +040028 ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
Bryan Schumakerc2e81392010-08-11 09:37:53 +010029 else
30 ret = -ESRCH;
31 kfree(ip_addr);
32 return ret;
33}
34
35#else
36
Bryan Schumaker89d77c82012-07-30 16:05:25 -040037#include <linux/module.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040038#include <linux/hash.h>
39#include <linux/string.h>
40#include <linux/kmod.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090041#include <linux/slab.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040042#include <linux/socket.h>
43#include <linux/seq_file.h>
44#include <linux/inet.h>
45#include <linux/sunrpc/clnt.h>
Jeff Layton59766872013-02-04 12:50:00 -050046#include <linux/sunrpc/addr.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040047#include <linux/sunrpc/cache.h>
48#include <linux/sunrpc/svcauth.h>
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +030049#include <linux/sunrpc/rpc_pipe_fs.h>
Anna Schumaker694e0962013-11-13 12:29:08 -050050#include <linux/nfs_fs.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040051
Anna Schumaker694e0962013-11-13 12:29:08 -050052#include "nfs4_fs.h"
Trond Myklebuste571cbf2009-08-19 18:12:27 -040053#include "dns_resolve.h"
54#include "cache_lib.h"
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +030055#include "netns.h"
Trond Myklebuste571cbf2009-08-19 18:12:27 -040056
57#define NFS_DNS_HASHBITS 4
58#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
59
Trond Myklebuste571cbf2009-08-19 18:12:27 -040060struct nfs_dns_ent {
61 struct cache_head h;
62
63 char *hostname;
64 size_t namelen;
65
66 struct sockaddr_storage addr;
67 size_t addrlen;
Trond Myklebust437f9142018-10-01 10:41:50 -040068 struct rcu_head rcu_head;
Trond Myklebuste571cbf2009-08-19 18:12:27 -040069};
70
71
Trond Myklebustebed9202010-03-02 13:06:22 -050072static void nfs_dns_ent_update(struct cache_head *cnew,
73 struct cache_head *ckey)
74{
75 struct nfs_dns_ent *new;
76 struct nfs_dns_ent *key;
77
78 new = container_of(cnew, struct nfs_dns_ent, h);
79 key = container_of(ckey, struct nfs_dns_ent, h);
80
81 memcpy(&new->addr, &key->addr, key->addrlen);
82 new->addrlen = key->addrlen;
83}
84
Trond Myklebuste571cbf2009-08-19 18:12:27 -040085static void nfs_dns_ent_init(struct cache_head *cnew,
86 struct cache_head *ckey)
87{
88 struct nfs_dns_ent *new;
89 struct nfs_dns_ent *key;
90
91 new = container_of(cnew, struct nfs_dns_ent, h);
92 key = container_of(ckey, struct nfs_dns_ent, h);
93
94 kfree(new->hostname);
Trond Myklebusta8bd9dd2020-02-02 17:57:07 -050095 new->hostname = kmemdup_nul(key->hostname, key->namelen, GFP_KERNEL);
Trond Myklebuste571cbf2009-08-19 18:12:27 -040096 if (new->hostname) {
97 new->namelen = key->namelen;
Trond Myklebustebed9202010-03-02 13:06:22 -050098 nfs_dns_ent_update(cnew, ckey);
Trond Myklebuste571cbf2009-08-19 18:12:27 -040099 } else {
100 new->namelen = 0;
101 new->addrlen = 0;
102 }
103}
104
Trond Myklebust437f9142018-10-01 10:41:50 -0400105static void nfs_dns_ent_free_rcu(struct rcu_head *head)
106{
107 struct nfs_dns_ent *item;
108
109 item = container_of(head, struct nfs_dns_ent, rcu_head);
110 kfree(item->hostname);
111 kfree(item);
112}
113
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400114static void nfs_dns_ent_put(struct kref *ref)
115{
116 struct nfs_dns_ent *item;
117
118 item = container_of(ref, struct nfs_dns_ent, h.ref);
Trond Myklebusta6482732018-10-05 10:27:20 -0400119 call_rcu(&item->rcu_head, nfs_dns_ent_free_rcu);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400120}
121
122static struct cache_head *nfs_dns_ent_alloc(void)
123{
124 struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL);
125
126 if (item != NULL) {
127 item->hostname = NULL;
128 item->namelen = 0;
129 item->addrlen = 0;
130 return &item->h;
131 }
132 return NULL;
133};
134
135static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
136{
137 return hash_str(key->hostname, NFS_DNS_HASHBITS);
138}
139
140static void nfs_dns_request(struct cache_detail *cd,
141 struct cache_head *ch,
142 char **bpp, int *blen)
143{
144 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
145
146 qword_add(bpp, blen, key->hostname);
147 (*bpp)[-1] = '\n';
148}
149
150static int nfs_dns_upcall(struct cache_detail *cd,
151 struct cache_head *ch)
152{
153 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400154
Trond Myklebust65286b82020-03-01 18:21:42 -0500155 if (test_and_set_bit(CACHE_PENDING, &ch->flags))
156 return 0;
157 if (!nfs_cache_upcall(cd, key->hostname))
158 return 0;
159 clear_bit(CACHE_PENDING, &ch->flags);
160 return sunrpc_cache_pipe_upcall_timeout(cd, ch);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400161}
162
163static int nfs_dns_match(struct cache_head *ca,
164 struct cache_head *cb)
165{
166 struct nfs_dns_ent *a;
167 struct nfs_dns_ent *b;
168
169 a = container_of(ca, struct nfs_dns_ent, h);
170 b = container_of(cb, struct nfs_dns_ent, h);
171
172 if (a->namelen == 0 || a->namelen != b->namelen)
173 return 0;
174 return memcmp(a->hostname, b->hostname, a->namelen) == 0;
175}
176
177static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
178 struct cache_head *h)
179{
180 struct nfs_dns_ent *item;
181 long ttl;
182
183 if (h == NULL) {
184 seq_puts(m, "# ip address hostname ttl\n");
185 return 0;
186 }
187 item = container_of(h, struct nfs_dns_ent, h);
NeilBrownc5b29f82010-08-12 16:55:22 +1000188 ttl = item->h.expiry_time - seconds_since_boot();
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400189 if (ttl < 0)
190 ttl = 0;
191
192 if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
193 char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
194
195 rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
196 seq_printf(m, "%15s ", buf);
197 } else
198 seq_puts(m, "<none> ");
199 seq_printf(m, "%15s %ld\n", item->hostname, ttl);
200 return 0;
201}
202
Trond Myklebust0a6566e2009-12-03 15:54:01 -0500203static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400204 struct nfs_dns_ent *key)
205{
206 struct cache_head *ch;
207
Trond Myklebust437f9142018-10-01 10:41:50 -0400208 ch = sunrpc_cache_lookup_rcu(cd,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400209 &key->h,
210 nfs_dns_hash(key));
211 if (!ch)
212 return NULL;
213 return container_of(ch, struct nfs_dns_ent, h);
214}
215
Trond Myklebust0a6566e2009-12-03 15:54:01 -0500216static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400217 struct nfs_dns_ent *new,
218 struct nfs_dns_ent *key)
219{
220 struct cache_head *ch;
221
222 ch = sunrpc_cache_update(cd,
223 &new->h, &key->h,
224 nfs_dns_hash(key));
225 if (!ch)
226 return NULL;
227 return container_of(ch, struct nfs_dns_ent, h);
228}
229
230static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
231{
232 char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
233 struct nfs_dns_ent key, *item;
NeilBrown8d96b102012-10-31 12:16:01 +1100234 unsigned int ttl;
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400235 ssize_t len;
236 int ret = -EINVAL;
237
238 if (buf[buflen-1] != '\n')
239 goto out;
240 buf[buflen-1] = '\0';
241
242 len = qword_get(&buf, buf1, sizeof(buf1));
243 if (len <= 0)
244 goto out;
Stanislav Kinsbursky599ec122012-01-19 18:51:04 +0400245 key.addrlen = rpc_pton(cd->net, buf1, len,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400246 (struct sockaddr *)&key.addr,
247 sizeof(key.addr));
248
249 len = qword_get(&buf, buf1, sizeof(buf1));
250 if (len <= 0)
251 goto out;
252
253 key.hostname = buf1;
254 key.namelen = len;
255 memset(&key.h, 0, sizeof(key.h));
256
NeilBrown8d96b102012-10-31 12:16:01 +1100257 if (get_uint(&buf, &ttl) < 0)
258 goto out;
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400259 if (ttl == 0)
260 goto out;
NeilBrownc5b29f82010-08-12 16:55:22 +1000261 key.h.expiry_time = ttl + seconds_since_boot();
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400262
263 ret = -ENOMEM;
264 item = nfs_dns_lookup(cd, &key);
265 if (item == NULL)
266 goto out;
267
268 if (key.addrlen == 0)
269 set_bit(CACHE_NEGATIVE, &key.h.flags);
270
271 item = nfs_dns_update(cd, &key, item);
272 if (item == NULL)
273 goto out;
274
275 ret = 0;
276 cache_put(&item->h, cd);
277out:
278 return ret;
279}
280
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400281static int do_cache_lookup(struct cache_detail *cd,
282 struct nfs_dns_ent *key,
283 struct nfs_dns_ent **item,
284 struct nfs_cache_defer_req *dreq)
285{
286 int ret = -ENOMEM;
287
288 *item = nfs_dns_lookup(cd, key);
289 if (*item) {
290 ret = cache_check(cd, &(*item)->h, &dreq->req);
291 if (ret)
292 *item = NULL;
293 }
294 return ret;
295}
296
297static int do_cache_lookup_nowait(struct cache_detail *cd,
298 struct nfs_dns_ent *key,
299 struct nfs_dns_ent **item)
300{
301 int ret = -ENOMEM;
302
303 *item = nfs_dns_lookup(cd, key);
304 if (!*item)
305 goto out_err;
306 ret = -ETIMEDOUT;
307 if (!test_bit(CACHE_VALID, &(*item)->h.flags)
NeilBrownc5b29f82010-08-12 16:55:22 +1000308 || (*item)->h.expiry_time < seconds_since_boot()
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400309 || cd->flush_time > (*item)->h.last_refresh)
310 goto out_put;
311 ret = -ENOENT;
312 if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
313 goto out_put;
314 return 0;
315out_put:
316 cache_put(&(*item)->h, cd);
317out_err:
318 *item = NULL;
319 return ret;
320}
321
322static int do_cache_lookup_wait(struct cache_detail *cd,
323 struct nfs_dns_ent *key,
324 struct nfs_dns_ent **item)
325{
326 struct nfs_cache_defer_req *dreq;
327 int ret = -ENOMEM;
328
329 dreq = nfs_cache_defer_req_alloc();
330 if (!dreq)
331 goto out;
332 ret = do_cache_lookup(cd, key, item, dreq);
333 if (ret == -EAGAIN) {
334 ret = nfs_cache_wait_for_upcall(dreq);
335 if (!ret)
336 ret = do_cache_lookup_nowait(cd, key, item);
337 }
338 nfs_cache_defer_req_put(dreq);
339out:
340 return ret;
341}
342
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300343ssize_t nfs_dns_resolve_name(struct net *net, char *name,
344 size_t namelen, struct sockaddr *sa, size_t salen)
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400345{
346 struct nfs_dns_ent key = {
347 .hostname = name,
348 .namelen = namelen,
349 };
350 struct nfs_dns_ent *item = NULL;
351 ssize_t ret;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300352 struct nfs_net *nn = net_generic(net, nfs_net_id);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400353
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300354 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400355 if (ret == 0) {
356 if (salen >= item->addrlen) {
357 memcpy(sa, &item->addr, item->addrlen);
358 ret = item->addrlen;
359 } else
360 ret = -EOVERFLOW;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300361 cache_put(&item->h, nn->nfs_dns_resolve);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400362 } else if (ret == -ENOENT)
363 ret = -ESRCH;
364 return ret;
365}
366
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300367static struct cache_detail nfs_dns_resolve_template = {
368 .owner = THIS_MODULE,
369 .hash_size = NFS_DNS_HASHTBL_SIZE,
370 .name = "dns_resolve",
371 .cache_put = nfs_dns_ent_put,
372 .cache_upcall = nfs_dns_upcall,
Stanislav Kinsbursky73fb8472013-02-04 14:02:45 +0300373 .cache_request = nfs_dns_request,
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300374 .cache_parse = nfs_dns_parse,
375 .cache_show = nfs_dns_show,
376 .match = nfs_dns_match,
377 .init = nfs_dns_ent_init,
378 .update = nfs_dns_ent_update,
379 .alloc = nfs_dns_ent_alloc,
380};
381
382
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300383int nfs_dns_resolver_cache_init(struct net *net)
384{
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300385 int err;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300386 struct nfs_net *nn = net_generic(net, nfs_net_id);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300387
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300388 nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
389 if (IS_ERR(nn->nfs_dns_resolve))
390 return PTR_ERR(nn->nfs_dns_resolve);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300391
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300392 err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300393 if (err)
394 goto err_reg;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300395 return 0;
396
397err_reg:
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300398 cache_destroy_net(nn->nfs_dns_resolve, net);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300399 return err;
400}
401
402void nfs_dns_resolver_cache_destroy(struct net *net)
403{
404 struct nfs_net *nn = net_generic(net, nfs_net_id);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300405
Stanislav Kinsbursky462b8f62013-02-04 14:02:40 +0300406 nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300407 cache_destroy_net(nn->nfs_dns_resolve, net);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300408}
409
Trond Myklebustc8d74d92013-06-01 11:50:58 -0400410static int nfs4_dns_net_init(struct net *net)
411{
412 return nfs_dns_resolver_cache_init(net);
413}
414
415static void nfs4_dns_net_exit(struct net *net)
416{
417 nfs_dns_resolver_cache_destroy(net);
418}
419
420static struct pernet_operations nfs4_dns_resolver_ops = {
421 .init = nfs4_dns_net_init,
422 .exit = nfs4_dns_net_exit,
423};
424
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +0300425static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
426 void *ptr)
427{
428 struct super_block *sb = ptr;
429 struct net *net = sb->s_fs_info;
430 struct nfs_net *nn = net_generic(net, nfs_net_id);
431 struct cache_detail *cd = nn->nfs_dns_resolve;
432 int ret = 0;
433
434 if (cd == NULL)
435 return 0;
436
437 if (!try_module_get(THIS_MODULE))
438 return 0;
439
440 switch (event) {
441 case RPC_PIPEFS_MOUNT:
442 ret = nfs_cache_register_sb(sb, cd);
443 break;
444 case RPC_PIPEFS_UMOUNT:
445 nfs_cache_unregister_sb(sb, cd);
446 break;
447 default:
448 ret = -ENOTSUPP;
449 break;
450 }
451 module_put(THIS_MODULE);
452 return ret;
453}
454
455static struct notifier_block nfs_dns_resolver_block = {
456 .notifier_call = rpc_pipefs_event,
457};
458
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400459int nfs_dns_resolver_init(void)
460{
Trond Myklebustc8d74d92013-06-01 11:50:58 -0400461 int err;
462
463 err = register_pernet_subsys(&nfs4_dns_resolver_ops);
464 if (err < 0)
465 goto out;
466 err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
467 if (err < 0)
468 goto out1;
469 return 0;
470out1:
471 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
472out:
473 return err;
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400474}
475
476void nfs_dns_resolver_destroy(void)
477{
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +0300478 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
Trond Myklebustc8d74d92013-06-01 11:50:58 -0400479 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400480}
Bryan Schumakerc2e81392010-08-11 09:37:53 +0100481#endif