blob: 200eb67c95d972d81adf1a4401d796757b794676 [file] [log] [blame]
Trond Myklebuste571cbf2009-08-19 18:12:27 -04001/*
2 * linux/fs/nfs/dns_resolve.c
3 *
4 * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com>
5 *
6 * Resolves DNS hostnames into valid ip addresses
7 */
8
Bryan Schumakerc2e81392010-08-11 09:37:53 +01009#ifdef CONFIG_NFS_USE_KERNEL_DNS
10
11#include <linux/sunrpc/clnt.h>
12#include <linux/dns_resolver.h>
13
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +030014ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
Bryan Schumakerc2e81392010-08-11 09:37:53 +010015 struct sockaddr *sa, size_t salen)
16{
17 ssize_t ret;
18 char *ip_addr = NULL;
19 int ip_len;
20
21 ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL);
22 if (ip_len > 0)
23 ret = rpc_pton(ip_addr, ip_len, sa, salen);
24 else
25 ret = -ESRCH;
26 kfree(ip_addr);
27 return ret;
28}
29
30#else
31
Trond Myklebuste571cbf2009-08-19 18:12:27 -040032#include <linux/hash.h>
33#include <linux/string.h>
34#include <linux/kmod.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090035#include <linux/slab.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040036#include <linux/module.h>
37#include <linux/socket.h>
38#include <linux/seq_file.h>
39#include <linux/inet.h>
40#include <linux/sunrpc/clnt.h>
41#include <linux/sunrpc/cache.h>
42#include <linux/sunrpc/svcauth.h>
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +030043#include <linux/sunrpc/rpc_pipe_fs.h>
Trond Myklebuste571cbf2009-08-19 18:12:27 -040044
45#include "dns_resolve.h"
46#include "cache_lib.h"
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +030047#include "netns.h"
Trond Myklebuste571cbf2009-08-19 18:12:27 -040048
49#define NFS_DNS_HASHBITS 4
50#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
51
Trond Myklebuste571cbf2009-08-19 18:12:27 -040052struct nfs_dns_ent {
53 struct cache_head h;
54
55 char *hostname;
56 size_t namelen;
57
58 struct sockaddr_storage addr;
59 size_t addrlen;
60};
61
62
Trond Myklebustebed9202010-03-02 13:06:22 -050063static void nfs_dns_ent_update(struct cache_head *cnew,
64 struct cache_head *ckey)
65{
66 struct nfs_dns_ent *new;
67 struct nfs_dns_ent *key;
68
69 new = container_of(cnew, struct nfs_dns_ent, h);
70 key = container_of(ckey, struct nfs_dns_ent, h);
71
72 memcpy(&new->addr, &key->addr, key->addrlen);
73 new->addrlen = key->addrlen;
74}
75
Trond Myklebuste571cbf2009-08-19 18:12:27 -040076static void nfs_dns_ent_init(struct cache_head *cnew,
77 struct cache_head *ckey)
78{
79 struct nfs_dns_ent *new;
80 struct nfs_dns_ent *key;
81
82 new = container_of(cnew, struct nfs_dns_ent, h);
83 key = container_of(ckey, struct nfs_dns_ent, h);
84
85 kfree(new->hostname);
86 new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL);
87 if (new->hostname) {
88 new->namelen = key->namelen;
Trond Myklebustebed9202010-03-02 13:06:22 -050089 nfs_dns_ent_update(cnew, ckey);
Trond Myklebuste571cbf2009-08-19 18:12:27 -040090 } else {
91 new->namelen = 0;
92 new->addrlen = 0;
93 }
94}
95
96static void nfs_dns_ent_put(struct kref *ref)
97{
98 struct nfs_dns_ent *item;
99
100 item = container_of(ref, struct nfs_dns_ent, h.ref);
101 kfree(item->hostname);
102 kfree(item);
103}
104
105static struct cache_head *nfs_dns_ent_alloc(void)
106{
107 struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL);
108
109 if (item != NULL) {
110 item->hostname = NULL;
111 item->namelen = 0;
112 item->addrlen = 0;
113 return &item->h;
114 }
115 return NULL;
116};
117
118static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
119{
120 return hash_str(key->hostname, NFS_DNS_HASHBITS);
121}
122
123static void nfs_dns_request(struct cache_detail *cd,
124 struct cache_head *ch,
125 char **bpp, int *blen)
126{
127 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
128
129 qword_add(bpp, blen, key->hostname);
130 (*bpp)[-1] = '\n';
131}
132
133static int nfs_dns_upcall(struct cache_detail *cd,
134 struct cache_head *ch)
135{
136 struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
137 int ret;
138
139 ret = nfs_cache_upcall(cd, key->hostname);
140 if (ret)
141 ret = sunrpc_cache_pipe_upcall(cd, ch, nfs_dns_request);
142 return ret;
143}
144
145static int nfs_dns_match(struct cache_head *ca,
146 struct cache_head *cb)
147{
148 struct nfs_dns_ent *a;
149 struct nfs_dns_ent *b;
150
151 a = container_of(ca, struct nfs_dns_ent, h);
152 b = container_of(cb, struct nfs_dns_ent, h);
153
154 if (a->namelen == 0 || a->namelen != b->namelen)
155 return 0;
156 return memcmp(a->hostname, b->hostname, a->namelen) == 0;
157}
158
159static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
160 struct cache_head *h)
161{
162 struct nfs_dns_ent *item;
163 long ttl;
164
165 if (h == NULL) {
166 seq_puts(m, "# ip address hostname ttl\n");
167 return 0;
168 }
169 item = container_of(h, struct nfs_dns_ent, h);
NeilBrownc5b29f82010-08-12 16:55:22 +1000170 ttl = item->h.expiry_time - seconds_since_boot();
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400171 if (ttl < 0)
172 ttl = 0;
173
174 if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
175 char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
176
177 rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
178 seq_printf(m, "%15s ", buf);
179 } else
180 seq_puts(m, "<none> ");
181 seq_printf(m, "%15s %ld\n", item->hostname, ttl);
182 return 0;
183}
184
Trond Myklebust0a6566e2009-12-03 15:54:01 -0500185static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400186 struct nfs_dns_ent *key)
187{
188 struct cache_head *ch;
189
190 ch = sunrpc_cache_lookup(cd,
191 &key->h,
192 nfs_dns_hash(key));
193 if (!ch)
194 return NULL;
195 return container_of(ch, struct nfs_dns_ent, h);
196}
197
Trond Myklebust0a6566e2009-12-03 15:54:01 -0500198static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400199 struct nfs_dns_ent *new,
200 struct nfs_dns_ent *key)
201{
202 struct cache_head *ch;
203
204 ch = sunrpc_cache_update(cd,
205 &new->h, &key->h,
206 nfs_dns_hash(key));
207 if (!ch)
208 return NULL;
209 return container_of(ch, struct nfs_dns_ent, h);
210}
211
212static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
213{
214 char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
215 struct nfs_dns_ent key, *item;
216 unsigned long ttl;
217 ssize_t len;
218 int ret = -EINVAL;
219
220 if (buf[buflen-1] != '\n')
221 goto out;
222 buf[buflen-1] = '\0';
223
224 len = qword_get(&buf, buf1, sizeof(buf1));
225 if (len <= 0)
226 goto out;
227 key.addrlen = rpc_pton(buf1, len,
228 (struct sockaddr *)&key.addr,
229 sizeof(key.addr));
230
231 len = qword_get(&buf, buf1, sizeof(buf1));
232 if (len <= 0)
233 goto out;
234
235 key.hostname = buf1;
236 key.namelen = len;
237 memset(&key.h, 0, sizeof(key.h));
238
239 ttl = get_expiry(&buf);
240 if (ttl == 0)
241 goto out;
NeilBrownc5b29f82010-08-12 16:55:22 +1000242 key.h.expiry_time = ttl + seconds_since_boot();
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400243
244 ret = -ENOMEM;
245 item = nfs_dns_lookup(cd, &key);
246 if (item == NULL)
247 goto out;
248
249 if (key.addrlen == 0)
250 set_bit(CACHE_NEGATIVE, &key.h.flags);
251
252 item = nfs_dns_update(cd, &key, item);
253 if (item == NULL)
254 goto out;
255
256 ret = 0;
257 cache_put(&item->h, cd);
258out:
259 return ret;
260}
261
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400262static int do_cache_lookup(struct cache_detail *cd,
263 struct nfs_dns_ent *key,
264 struct nfs_dns_ent **item,
265 struct nfs_cache_defer_req *dreq)
266{
267 int ret = -ENOMEM;
268
269 *item = nfs_dns_lookup(cd, key);
270 if (*item) {
271 ret = cache_check(cd, &(*item)->h, &dreq->req);
272 if (ret)
273 *item = NULL;
274 }
275 return ret;
276}
277
278static int do_cache_lookup_nowait(struct cache_detail *cd,
279 struct nfs_dns_ent *key,
280 struct nfs_dns_ent **item)
281{
282 int ret = -ENOMEM;
283
284 *item = nfs_dns_lookup(cd, key);
285 if (!*item)
286 goto out_err;
287 ret = -ETIMEDOUT;
288 if (!test_bit(CACHE_VALID, &(*item)->h.flags)
NeilBrownc5b29f82010-08-12 16:55:22 +1000289 || (*item)->h.expiry_time < seconds_since_boot()
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400290 || cd->flush_time > (*item)->h.last_refresh)
291 goto out_put;
292 ret = -ENOENT;
293 if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
294 goto out_put;
295 return 0;
296out_put:
297 cache_put(&(*item)->h, cd);
298out_err:
299 *item = NULL;
300 return ret;
301}
302
303static int do_cache_lookup_wait(struct cache_detail *cd,
304 struct nfs_dns_ent *key,
305 struct nfs_dns_ent **item)
306{
307 struct nfs_cache_defer_req *dreq;
308 int ret = -ENOMEM;
309
310 dreq = nfs_cache_defer_req_alloc();
311 if (!dreq)
312 goto out;
313 ret = do_cache_lookup(cd, key, item, dreq);
314 if (ret == -EAGAIN) {
315 ret = nfs_cache_wait_for_upcall(dreq);
316 if (!ret)
317 ret = do_cache_lookup_nowait(cd, key, item);
318 }
319 nfs_cache_defer_req_put(dreq);
320out:
321 return ret;
322}
323
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300324ssize_t nfs_dns_resolve_name(struct net *net, char *name,
325 size_t namelen, struct sockaddr *sa, size_t salen)
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400326{
327 struct nfs_dns_ent key = {
328 .hostname = name,
329 .namelen = namelen,
330 };
331 struct nfs_dns_ent *item = NULL;
332 ssize_t ret;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300333 struct nfs_net *nn = net_generic(net, nfs_net_id);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400334
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300335 ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400336 if (ret == 0) {
337 if (salen >= item->addrlen) {
338 memcpy(sa, &item->addr, item->addrlen);
339 ret = item->addrlen;
340 } else
341 ret = -EOVERFLOW;
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300342 cache_put(&item->h, nn->nfs_dns_resolve);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400343 } else if (ret == -ENOENT)
344 ret = -ESRCH;
345 return ret;
346}
347
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300348int nfs_dns_resolver_cache_init(struct net *net)
349{
350 int err = -ENOMEM;
351 struct nfs_net *nn = net_generic(net, nfs_net_id);
352 struct cache_detail *cd;
353 struct cache_head **tbl;
354
355 cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL);
356 if (cd == NULL)
357 goto err_cd;
358
359 tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *),
360 GFP_KERNEL);
361 if (tbl == NULL)
362 goto err_tbl;
363
364 cd->owner = THIS_MODULE,
365 cd->hash_size = NFS_DNS_HASHTBL_SIZE,
366 cd->hash_table = tbl,
367 cd->name = "dns_resolve",
368 cd->cache_put = nfs_dns_ent_put,
369 cd->cache_upcall = nfs_dns_upcall,
370 cd->cache_parse = nfs_dns_parse,
371 cd->cache_show = nfs_dns_show,
372 cd->match = nfs_dns_match,
373 cd->init = nfs_dns_ent_init,
374 cd->update = nfs_dns_ent_update,
375 cd->alloc = nfs_dns_ent_alloc,
376
377 nfs_cache_init(cd);
378 err = nfs_cache_register_net(net, cd);
379 if (err)
380 goto err_reg;
381 nn->nfs_dns_resolve = cd;
382 return 0;
383
384err_reg:
385 nfs_cache_destroy(cd);
386 kfree(cd->hash_table);
387err_tbl:
388 kfree(cd);
389err_cd:
390 return err;
391}
392
393void nfs_dns_resolver_cache_destroy(struct net *net)
394{
395 struct nfs_net *nn = net_generic(net, nfs_net_id);
396 struct cache_detail *cd = nn->nfs_dns_resolve;
397
398 nfs_cache_unregister_net(net, cd);
399 nfs_cache_destroy(cd);
400 kfree(cd->hash_table);
401 kfree(cd);
402}
403
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +0300404static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
405 void *ptr)
406{
407 struct super_block *sb = ptr;
408 struct net *net = sb->s_fs_info;
409 struct nfs_net *nn = net_generic(net, nfs_net_id);
410 struct cache_detail *cd = nn->nfs_dns_resolve;
411 int ret = 0;
412
413 if (cd == NULL)
414 return 0;
415
416 if (!try_module_get(THIS_MODULE))
417 return 0;
418
419 switch (event) {
420 case RPC_PIPEFS_MOUNT:
421 ret = nfs_cache_register_sb(sb, cd);
422 break;
423 case RPC_PIPEFS_UMOUNT:
424 nfs_cache_unregister_sb(sb, cd);
425 break;
426 default:
427 ret = -ENOTSUPP;
428 break;
429 }
430 module_put(THIS_MODULE);
431 return ret;
432}
433
434static struct notifier_block nfs_dns_resolver_block = {
435 .notifier_call = rpc_pipefs_event,
436};
437
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400438int nfs_dns_resolver_init(void)
439{
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +0300440 return rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400441}
442
443void nfs_dns_resolver_destroy(void)
444{
Stanislav Kinsbursky9df69c82011-11-25 17:13:12 +0300445 rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
Trond Myklebuste571cbf2009-08-19 18:12:27 -0400446}
Bryan Schumakerc2e81392010-08-11 09:37:53 +0100447#endif