blob: 060c658eab6600ebb0cf2dfa069d70d4e0f152a0 [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
25 ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL);
26 if (ip_len > 0)
Stanislav Kinsburskybc224f52012-01-26 15:11:33 +040027 ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
Bryan Schumakerc2e81392010-08-11 09:37:53 +010028 else
29 ret = -ESRCH;
30 kfree(ip_addr);
31 return ret;
32}
33
34#else
35
Bryan Schumaker89d77c82012-07-30 16:05:25 -040036#include <linux/module.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040037#include <linux/hash.h>
38#include <linux/string.h>
39#include <linux/kmod.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090040#include <linux/slab.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040041#include <linux/module.h>
42#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;
68};
69
70
Trond Myklebustebed9202010-03-02 13:06:22 -050071static void nfs_dns_ent_update(struct cache_head *cnew,
72 struct cache_head *ckey)
73{
74 struct nfs_dns_ent *new;
75 struct nfs_dns_ent *key;
76
77 new = container_of(cnew, struct nfs_dns_ent, h);
78 key = container_of(ckey, struct nfs_dns_ent, h);
79
80 memcpy(&new->addr, &key->addr, key->addrlen);
81 new->addrlen = key->addrlen;
82}
83
Trond Myklebuste571cbf2009-08-19 18:12:27 -040084static void nfs_dns_ent_init(struct cache_head *cnew,
85 struct cache_head *ckey)
86{
87 struct nfs_dns_ent *new;
88 struct nfs_dns_ent *key;
89
90 new = container_of(cnew, struct nfs_dns_ent, h);
91 key = container_of(ckey, struct nfs_dns_ent, h);
92
93 kfree(new->hostname);
94 new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
95 if (new->hostname) {
96 new->namelen = key->namelen;
Trond Myklebustebed9202010-03-02 13:06:22 -050097 nfs_dns_ent_update(cnew, ckey);
Trond Myklebuste571cbf2009-08-19 18:12:27 -040098 } else {
99 new->namelen = 0;
100 new->addrlen = 0;
101 }
102}
103
104static void nfs_dns_ent_put(struct kref *ref)
105{
106 struct nfs_dns_ent *item;
107
108 item = container_of(ref, struct nfs_dns_ent, h.ref);
109 kfree(item->hostname);
110 kfree(item);
111}
112
113static struct cache_head *nfs_dns_ent_alloc(void)
114{
115 struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL);
116
117 if (item != NULL) {
118 item->hostname = NULL;
119 item->namelen = 0;
120 item->addrlen = 0;
121 return &item->h;
122 }
123 return NULL;
124};
125
126static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
127{
128 return hash_str(key->hostname, NFS_DNS_HASHBITS);
129}
130
131static void nfs_dns_request(struct cache_detail *cd,
132 struct cache_head *ch,
133 char **bpp, int *blen)
134{
135 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
136
137 qword_add(bpp, blen, key->hostname);
138 (*bpp)[-1] = '\n';
139}
140
141static int nfs_dns_upcall(struct cache_detail *cd,
142 struct cache_head *ch)
143{
144 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
145 int ret;
146
147 ret = nfs_cache_upcall(cd, key->hostname);
148 if (ret)
Stanislav Kinsbursky21cd1252013-02-04 14:02:55 +0300149 ret = sunrpc_cache_pipe_upcall(cd, ch);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400150 return ret;
151}
152
153static int nfs_dns_match(struct cache_head *ca,
154 struct cache_head *cb)
155{
156 struct nfs_dns_ent *a;
157 struct nfs_dns_ent *b;
158
159 a = container_of(ca, struct nfs_dns_ent, h);
160 b = container_of(cb, struct nfs_dns_ent, h);
161
162 if (a->namelen == 0 || a->namelen != b->namelen)
163 return 0;
164 return memcmp(a->hostname, b->hostname, a->namelen) == 0;
165}
166
167static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
168 struct cache_head *h)
169{
170 struct nfs_dns_ent *item;
171 long ttl;
172
173 if (h == NULL) {
174 seq_puts(m, "# ip address hostname ttl\n");
175 return 0;
176 }
177 item = container_of(h, struct nfs_dns_ent, h);
NeilBrownc5b29f82010-08-12 16:55:22 +1000178 ttl = item->h.expiry_time - seconds_since_boot();
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400179 if (ttl < 0)
180 ttl = 0;
181
182 if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
183 char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
184
185 rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
186 seq_printf(m, "%15s ", buf);
187 } else
188 seq_puts(m, "<none> ");
189 seq_printf(m, "%15s %ld\n", item->hostname, ttl);
190 return 0;
191}
192
Trond Myklebust0a6566e2009-12-03 15:54:01 -0500193static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400194 struct nfs_dns_ent *key)
195{
196 struct cache_head *ch;
197
198 ch = sunrpc_cache_lookup(cd,
199 &key->h,
200 nfs_dns_hash(key));
201 if (!ch)
202 return NULL;
203 return container_of(ch, struct nfs_dns_ent, h);
204}
205
Trond Myklebust0a6566e2009-12-03 15:54:01 -0500206static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400207 struct nfs_dns_ent *new,
208 struct nfs_dns_ent *key)
209{
210 struct cache_head *ch;
211
212 ch = sunrpc_cache_update(cd,
213 &new->h, &key->h,
214 nfs_dns_hash(key));
215 if (!ch)
216 return NULL;
217 return container_of(ch, struct nfs_dns_ent, h);
218}
219
220static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
221{
222 char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
223 struct nfs_dns_ent key, *item;
NeilBrown8d96b102012-10-31 12:16:01 +1100224 unsigned int ttl;
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400225 ssize_t len;
226 int ret = -EINVAL;
227
228 if (buf[buflen-1] != '\n')
229 goto out;
230 buf[buflen-1] = '\0';
231
232 len = qword_get(&buf, buf1, sizeof(buf1));
233 if (len <= 0)
234 goto out;
Stanislav Kinsbursky599ec122012-01-19 18:51:04 +0400235 key.addrlen = rpc_pton(cd->net, buf1, len,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400236 (struct sockaddr *)&key.addr,
237 sizeof(key.addr));
238
239 len = qword_get(&buf, buf1, sizeof(buf1));
240 if (len <= 0)
241 goto out;
242
243 key.hostname = buf1;
244 key.namelen = len;
245 memset(&key.h, 0, sizeof(key.h));
246
NeilBrown8d96b102012-10-31 12:16:01 +1100247 if (get_uint(&buf, &ttl) < 0)
248 goto out;
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400249 if (ttl == 0)
250 goto out;
NeilBrownc5b29f82010-08-12 16:55:22 +1000251 key.h.expiry_time = ttl + seconds_since_boot();
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400252
253 ret = -ENOMEM;
254 item = nfs_dns_lookup(cd, &key);
255 if (item == NULL)
256 goto out;
257
258 if (key.addrlen == 0)
259 set_bit(CACHE_NEGATIVE, &key.h.flags);
260
261 item = nfs_dns_update(cd, &key, item);
262 if (item == NULL)
263 goto out;
264
265 ret = 0;
266 cache_put(&item->h, cd);
267out:
268 return ret;
269}
270
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400271static int do_cache_lookup(struct cache_detail *cd,
272 struct nfs_dns_ent *key,
273 struct nfs_dns_ent **item,
274 struct nfs_cache_defer_req *dreq)
275{
276 int ret = -ENOMEM;
277
278 *item = nfs_dns_lookup(cd, key);
279 if (*item) {
280 ret = cache_check(cd, &(*item)->h, &dreq->req);
281 if (ret)
282 *item = NULL;
283 }
284 return ret;
285}
286
287static int do_cache_lookup_nowait(struct cache_detail *cd,
288 struct nfs_dns_ent *key,
289 struct nfs_dns_ent **item)
290{
291 int ret = -ENOMEM;
292
293 *item = nfs_dns_lookup(cd, key);
294 if (!*item)
295 goto out_err;
296 ret = -ETIMEDOUT;
297 if (!test_bit(CACHE_VALID, &(*item)->h.flags)
NeilBrownc5b29f82010-08-12 16:55:22 +1000298 || (*item)->h.expiry_time < seconds_since_boot()
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400299 || cd->flush_time > (*item)->h.last_refresh)
300 goto out_put;
301 ret = -ENOENT;
302 if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
303 goto out_put;
304 return 0;
305out_put:
306 cache_put(&(*item)->h, cd);
307out_err:
308 *item = NULL;
309 return ret;
310}
311
312static int do_cache_lookup_wait(struct cache_detail *cd,
313 struct nfs_dns_ent *key,
314 struct nfs_dns_ent **item)
315{
316 struct nfs_cache_defer_req *dreq;
317 int ret = -ENOMEM;
318
319 dreq = nfs_cache_defer_req_alloc();
320 if (!dreq)
321 goto out;
322 ret = do_cache_lookup(cd, key, item, dreq);
323 if (ret == -EAGAIN) {
324 ret = nfs_cache_wait_for_upcall(dreq);
325 if (!ret)
326 ret = do_cache_lookup_nowait(cd, key, item);
327 }
328 nfs_cache_defer_req_put(dreq);
329out:
330 return ret;
331}
332
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300333ssize_t nfs_dns_resolve_name(struct net *net, char *name,
334 size_t namelen, struct sockaddr *sa, size_t salen)
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400335{
336 struct nfs_dns_ent key = {
337 .hostname = name,
338 .namelen = namelen,
339 };
340 struct nfs_dns_ent *item = NULL;
341 ssize_t ret;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300342 struct nfs_net *nn = net_generic(net, nfs_net_id);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400343
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300344 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400345 if (ret == 0) {
346 if (salen >= item->addrlen) {
347 memcpy(sa, &item->addr, item->addrlen);
348 ret = item->addrlen;
349 } else
350 ret = -EOVERFLOW;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300351 cache_put(&item->h, nn->nfs_dns_resolve);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400352 } else if (ret == -ENOENT)
353 ret = -ESRCH;
354 return ret;
355}
356
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300357static struct cache_detail nfs_dns_resolve_template = {
358 .owner = THIS_MODULE,
359 .hash_size = NFS_DNS_HASHTBL_SIZE,
360 .name = "dns_resolve",
361 .cache_put = nfs_dns_ent_put,
362 .cache_upcall = nfs_dns_upcall,
Stanislav Kinsbursky73fb8472013-02-04 14:02:45 +0300363 .cache_request = nfs_dns_request,
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300364 .cache_parse = nfs_dns_parse,
365 .cache_show = nfs_dns_show,
366 .match = nfs_dns_match,
367 .init = nfs_dns_ent_init,
368 .update = nfs_dns_ent_update,
369 .alloc = nfs_dns_ent_alloc,
370};
371
372
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300373int nfs_dns_resolver_cache_init(struct net *net)
374{
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300375 int err;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300376 struct nfs_net *nn = net_generic(net, nfs_net_id);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300377
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300378 nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
379 if (IS_ERR(nn->nfs_dns_resolve))
380 return PTR_ERR(nn->nfs_dns_resolve);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300381
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300382 err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300383 if (err)
384 goto err_reg;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300385 return 0;
386
387err_reg:
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300388 cache_destroy_net(nn->nfs_dns_resolve, net);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300389 return err;
390}
391
392void nfs_dns_resolver_cache_destroy(struct net *net)
393{
394 struct nfs_net *nn = net_generic(net, nfs_net_id);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300395
Stanislav Kinsbursky462b8f62013-02-04 14:02:40 +0300396 nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
Stanislav Kinsbursky483479c2013-02-04 14:02:35 +0300397 cache_destroy_net(nn->nfs_dns_resolve, net);
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300398}
399
Trond Myklebustc8d74d92013-06-01 11:50:58 -0400400static int nfs4_dns_net_init(struct net *net)
401{
402 return nfs_dns_resolver_cache_init(net);
403}
404
405static void nfs4_dns_net_exit(struct net *net)
406{
407 nfs_dns_resolver_cache_destroy(net);
408}
409
410static struct pernet_operations nfs4_dns_resolver_ops = {
411 .init = nfs4_dns_net_init,
412 .exit = nfs4_dns_net_exit,
413};
414
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +0300415static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
416 void *ptr)
417{
418 struct super_block *sb = ptr;
419 struct net *net = sb->s_fs_info;
420 struct nfs_net *nn = net_generic(net, nfs_net_id);
421 struct cache_detail *cd = nn->nfs_dns_resolve;
422 int ret = 0;
423
424 if (cd == NULL)
425 return 0;
426
427 if (!try_module_get(THIS_MODULE))
428 return 0;
429
430 switch (event) {
431 case RPC_PIPEFS_MOUNT:
432 ret = nfs_cache_register_sb(sb, cd);
433 break;
434 case RPC_PIPEFS_UMOUNT:
435 nfs_cache_unregister_sb(sb, cd);
436 break;
437 default:
438 ret = -ENOTSUPP;
439 break;
440 }
441 module_put(THIS_MODULE);
442 return ret;
443}
444
445static struct notifier_block nfs_dns_resolver_block = {
446 .notifier_call = rpc_pipefs_event,
447};
448
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400449int nfs_dns_resolver_init(void)
450{
Trond Myklebustc8d74d92013-06-01 11:50:58 -0400451 int err;
452
453 err = register_pernet_subsys(&nfs4_dns_resolver_ops);
454 if (err < 0)
455 goto out;
456 err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
457 if (err < 0)
458 goto out1;
459 return 0;
460out1:
461 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
462out:
463 return err;
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400464}
465
466void nfs_dns_resolver_destroy(void)
467{
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +0300468 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
Trond Myklebustc8d74d92013-06-01 11:50:58 -0400469 unregister_pernet_subsys(&nfs4_dns_resolver_ops);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400470}
Bryan Schumakerc2e81392010-08-11 09:37:53 +0100471#endif