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e571cbf1 TM |
1 | /* |
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 | ||
c2e8139c BS |
9 | #ifdef CONFIG_NFS_USE_KERNEL_DNS |
10 | ||
11 | #include <linux/sunrpc/clnt.h> | |
12 | #include <linux/dns_resolver.h> | |
17280175 | 13 | #include "dns_resolve.h" |
c2e8139c | 14 | |
1b340d01 | 15 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen, |
c2e8139c BS |
16 | struct sockaddr *sa, size_t salen) |
17 | { | |
18 | ssize_t ret; | |
19 | char *ip_addr = NULL; | |
20 | int ip_len; | |
21 | ||
22 | ip_len = dns_query(NULL, name, namelen, NULL, &ip_addr, NULL); | |
23 | if (ip_len > 0) | |
bc224f53 | 24 | ret = rpc_pton(net, ip_addr, ip_len, sa, salen); |
c2e8139c BS |
25 | else |
26 | ret = -ESRCH; | |
27 | kfree(ip_addr); | |
28 | return ret; | |
29 | } | |
30 | ||
31 | #else | |
32 | ||
e571cbf1 TM |
33 | #include <linux/hash.h> |
34 | #include <linux/string.h> | |
35 | #include <linux/kmod.h> | |
5a0e3ad6 | 36 | #include <linux/slab.h> |
e571cbf1 TM |
37 | #include <linux/module.h> |
38 | #include <linux/socket.h> | |
39 | #include <linux/seq_file.h> | |
40 | #include <linux/inet.h> | |
41 | #include <linux/sunrpc/clnt.h> | |
42 | #include <linux/sunrpc/cache.h> | |
43 | #include <linux/sunrpc/svcauth.h> | |
9df69c81 | 44 | #include <linux/sunrpc/rpc_pipe_fs.h> |
e571cbf1 TM |
45 | |
46 | #include "dns_resolve.h" | |
47 | #include "cache_lib.h" | |
1b340d01 | 48 | #include "netns.h" |
e571cbf1 TM |
49 | |
50 | #define NFS_DNS_HASHBITS 4 | |
51 | #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) | |
52 | ||
e571cbf1 TM |
53 | struct nfs_dns_ent { |
54 | struct cache_head h; | |
55 | ||
56 | char *hostname; | |
57 | size_t namelen; | |
58 | ||
59 | struct sockaddr_storage addr; | |
60 | size_t addrlen; | |
61 | }; | |
62 | ||
63 | ||
ebed9203 TM |
64 | static void nfs_dns_ent_update(struct cache_head *cnew, |
65 | struct cache_head *ckey) | |
66 | { | |
67 | struct nfs_dns_ent *new; | |
68 | struct nfs_dns_ent *key; | |
69 | ||
70 | new = container_of(cnew, struct nfs_dns_ent, h); | |
71 | key = container_of(ckey, struct nfs_dns_ent, h); | |
72 | ||
73 | memcpy(&new->addr, &key->addr, key->addrlen); | |
74 | new->addrlen = key->addrlen; | |
75 | } | |
76 | ||
e571cbf1 TM |
77 | static void nfs_dns_ent_init(struct cache_head *cnew, |
78 | struct cache_head *ckey) | |
79 | { | |
80 | struct nfs_dns_ent *new; | |
81 | struct nfs_dns_ent *key; | |
82 | ||
83 | new = container_of(cnew, struct nfs_dns_ent, h); | |
84 | key = container_of(ckey, struct nfs_dns_ent, h); | |
85 | ||
86 | kfree(new->hostname); | |
87 | new->hostname = kstrndup(key->hostname, key->namelen, GFP_KERNEL); | |
88 | if (new->hostname) { | |
89 | new->namelen = key->namelen; | |
ebed9203 | 90 | nfs_dns_ent_update(cnew, ckey); |
e571cbf1 TM |
91 | } else { |
92 | new->namelen = 0; | |
93 | new->addrlen = 0; | |
94 | } | |
95 | } | |
96 | ||
97 | static void nfs_dns_ent_put(struct kref *ref) | |
98 | { | |
99 | struct nfs_dns_ent *item; | |
100 | ||
101 | item = container_of(ref, struct nfs_dns_ent, h.ref); | |
102 | kfree(item->hostname); | |
103 | kfree(item); | |
104 | } | |
105 | ||
106 | static struct cache_head *nfs_dns_ent_alloc(void) | |
107 | { | |
108 | struct nfs_dns_ent *item = kmalloc(sizeof(*item), GFP_KERNEL); | |
109 | ||
110 | if (item != NULL) { | |
111 | item->hostname = NULL; | |
112 | item->namelen = 0; | |
113 | item->addrlen = 0; | |
114 | return &item->h; | |
115 | } | |
116 | return NULL; | |
117 | }; | |
118 | ||
119 | static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key) | |
120 | { | |
121 | return hash_str(key->hostname, NFS_DNS_HASHBITS); | |
122 | } | |
123 | ||
124 | static void nfs_dns_request(struct cache_detail *cd, | |
125 | struct cache_head *ch, | |
126 | char **bpp, int *blen) | |
127 | { | |
128 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
129 | ||
130 | qword_add(bpp, blen, key->hostname); | |
131 | (*bpp)[-1] = '\n'; | |
132 | } | |
133 | ||
134 | static int nfs_dns_upcall(struct cache_detail *cd, | |
135 | struct cache_head *ch) | |
136 | { | |
137 | struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h); | |
138 | int ret; | |
139 | ||
140 | ret = nfs_cache_upcall(cd, key->hostname); | |
141 | if (ret) | |
142 | ret = sunrpc_cache_pipe_upcall(cd, ch, nfs_dns_request); | |
143 | return ret; | |
144 | } | |
145 | ||
146 | static int nfs_dns_match(struct cache_head *ca, | |
147 | struct cache_head *cb) | |
148 | { | |
149 | struct nfs_dns_ent *a; | |
150 | struct nfs_dns_ent *b; | |
151 | ||
152 | a = container_of(ca, struct nfs_dns_ent, h); | |
153 | b = container_of(cb, struct nfs_dns_ent, h); | |
154 | ||
155 | if (a->namelen == 0 || a->namelen != b->namelen) | |
156 | return 0; | |
157 | return memcmp(a->hostname, b->hostname, a->namelen) == 0; | |
158 | } | |
159 | ||
160 | static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd, | |
161 | struct cache_head *h) | |
162 | { | |
163 | struct nfs_dns_ent *item; | |
164 | long ttl; | |
165 | ||
166 | if (h == NULL) { | |
167 | seq_puts(m, "# ip address hostname ttl\n"); | |
168 | return 0; | |
169 | } | |
170 | item = container_of(h, struct nfs_dns_ent, h); | |
c5b29f88 | 171 | ttl = item->h.expiry_time - seconds_since_boot(); |
e571cbf1 TM |
172 | if (ttl < 0) |
173 | ttl = 0; | |
174 | ||
175 | if (!test_bit(CACHE_NEGATIVE, &h->flags)) { | |
176 | char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1]; | |
177 | ||
178 | rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf)); | |
179 | seq_printf(m, "%15s ", buf); | |
180 | } else | |
181 | seq_puts(m, "<none> "); | |
182 | seq_printf(m, "%15s %ld\n", item->hostname, ttl); | |
183 | return 0; | |
184 | } | |
185 | ||
0a6566ec | 186 | static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, |
e571cbf1 TM |
187 | struct nfs_dns_ent *key) |
188 | { | |
189 | struct cache_head *ch; | |
190 | ||
191 | ch = sunrpc_cache_lookup(cd, | |
192 | &key->h, | |
193 | nfs_dns_hash(key)); | |
194 | if (!ch) | |
195 | return NULL; | |
196 | return container_of(ch, struct nfs_dns_ent, h); | |
197 | } | |
198 | ||
0a6566ec | 199 | static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd, |
e571cbf1 TM |
200 | struct nfs_dns_ent *new, |
201 | struct nfs_dns_ent *key) | |
202 | { | |
203 | struct cache_head *ch; | |
204 | ||
205 | ch = sunrpc_cache_update(cd, | |
206 | &new->h, &key->h, | |
207 | nfs_dns_hash(key)); | |
208 | if (!ch) | |
209 | return NULL; | |
210 | return container_of(ch, struct nfs_dns_ent, h); | |
211 | } | |
212 | ||
213 | static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) | |
214 | { | |
215 | char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; | |
216 | struct nfs_dns_ent key, *item; | |
217 | unsigned long ttl; | |
218 | ssize_t len; | |
219 | int ret = -EINVAL; | |
220 | ||
221 | if (buf[buflen-1] != '\n') | |
222 | goto out; | |
223 | buf[buflen-1] = '\0'; | |
224 | ||
225 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
226 | if (len <= 0) | |
227 | goto out; | |
599ec129 | 228 | key.addrlen = rpc_pton(cd->net, buf1, len, |
e571cbf1 TM |
229 | (struct sockaddr *)&key.addr, |
230 | sizeof(key.addr)); | |
231 | ||
232 | len = qword_get(&buf, buf1, sizeof(buf1)); | |
233 | if (len <= 0) | |
234 | goto out; | |
235 | ||
236 | key.hostname = buf1; | |
237 | key.namelen = len; | |
238 | memset(&key.h, 0, sizeof(key.h)); | |
239 | ||
240 | ttl = get_expiry(&buf); | |
241 | if (ttl == 0) | |
242 | goto out; | |
c5b29f88 | 243 | key.h.expiry_time = ttl + seconds_since_boot(); |
e571cbf1 TM |
244 | |
245 | ret = -ENOMEM; | |
246 | item = nfs_dns_lookup(cd, &key); | |
247 | if (item == NULL) | |
248 | goto out; | |
249 | ||
250 | if (key.addrlen == 0) | |
251 | set_bit(CACHE_NEGATIVE, &key.h.flags); | |
252 | ||
253 | item = nfs_dns_update(cd, &key, item); | |
254 | if (item == NULL) | |
255 | goto out; | |
256 | ||
257 | ret = 0; | |
258 | cache_put(&item->h, cd); | |
259 | out: | |
260 | return ret; | |
261 | } | |
262 | ||
e571cbf1 TM |
263 | static int do_cache_lookup(struct cache_detail *cd, |
264 | struct nfs_dns_ent *key, | |
265 | struct nfs_dns_ent **item, | |
266 | struct nfs_cache_defer_req *dreq) | |
267 | { | |
268 | int ret = -ENOMEM; | |
269 | ||
270 | *item = nfs_dns_lookup(cd, key); | |
271 | if (*item) { | |
272 | ret = cache_check(cd, &(*item)->h, &dreq->req); | |
273 | if (ret) | |
274 | *item = NULL; | |
275 | } | |
276 | return ret; | |
277 | } | |
278 | ||
279 | static int do_cache_lookup_nowait(struct cache_detail *cd, | |
280 | struct nfs_dns_ent *key, | |
281 | struct nfs_dns_ent **item) | |
282 | { | |
283 | int ret = -ENOMEM; | |
284 | ||
285 | *item = nfs_dns_lookup(cd, key); | |
286 | if (!*item) | |
287 | goto out_err; | |
288 | ret = -ETIMEDOUT; | |
289 | if (!test_bit(CACHE_VALID, &(*item)->h.flags) | |
c5b29f88 | 290 | || (*item)->h.expiry_time < seconds_since_boot() |
e571cbf1 TM |
291 | || cd->flush_time > (*item)->h.last_refresh) |
292 | goto out_put; | |
293 | ret = -ENOENT; | |
294 | if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags)) | |
295 | goto out_put; | |
296 | return 0; | |
297 | out_put: | |
298 | cache_put(&(*item)->h, cd); | |
299 | out_err: | |
300 | *item = NULL; | |
301 | return ret; | |
302 | } | |
303 | ||
304 | static int do_cache_lookup_wait(struct cache_detail *cd, | |
305 | struct nfs_dns_ent *key, | |
306 | struct nfs_dns_ent **item) | |
307 | { | |
308 | struct nfs_cache_defer_req *dreq; | |
309 | int ret = -ENOMEM; | |
310 | ||
311 | dreq = nfs_cache_defer_req_alloc(); | |
312 | if (!dreq) | |
313 | goto out; | |
314 | ret = do_cache_lookup(cd, key, item, dreq); | |
315 | if (ret == -EAGAIN) { | |
316 | ret = nfs_cache_wait_for_upcall(dreq); | |
317 | if (!ret) | |
318 | ret = do_cache_lookup_nowait(cd, key, item); | |
319 | } | |
320 | nfs_cache_defer_req_put(dreq); | |
321 | out: | |
322 | return ret; | |
323 | } | |
324 | ||
1b340d01 SK |
325 | ssize_t nfs_dns_resolve_name(struct net *net, char *name, |
326 | size_t namelen, struct sockaddr *sa, size_t salen) | |
e571cbf1 TM |
327 | { |
328 | struct nfs_dns_ent key = { | |
329 | .hostname = name, | |
330 | .namelen = namelen, | |
331 | }; | |
332 | struct nfs_dns_ent *item = NULL; | |
333 | ssize_t ret; | |
1b340d01 | 334 | struct nfs_net *nn = net_generic(net, nfs_net_id); |
e571cbf1 | 335 | |
1b340d01 | 336 | ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item); |
e571cbf1 TM |
337 | if (ret == 0) { |
338 | if (salen >= item->addrlen) { | |
339 | memcpy(sa, &item->addr, item->addrlen); | |
340 | ret = item->addrlen; | |
341 | } else | |
342 | ret = -EOVERFLOW; | |
1b340d01 | 343 | cache_put(&item->h, nn->nfs_dns_resolve); |
e571cbf1 TM |
344 | } else if (ret == -ENOENT) |
345 | ret = -ESRCH; | |
346 | return ret; | |
347 | } | |
348 | ||
1b340d01 | 349 | int nfs_dns_resolver_cache_init(struct net *net) |
e571cbf1 | 350 | { |
1b340d01 SK |
351 | int err = -ENOMEM; |
352 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
353 | struct cache_detail *cd; | |
354 | struct cache_head **tbl; | |
355 | ||
356 | cd = kzalloc(sizeof(struct cache_detail), GFP_KERNEL); | |
357 | if (cd == NULL) | |
358 | goto err_cd; | |
359 | ||
360 | tbl = kzalloc(NFS_DNS_HASHTBL_SIZE * sizeof(struct cache_head *), | |
361 | GFP_KERNEL); | |
362 | if (tbl == NULL) | |
363 | goto err_tbl; | |
364 | ||
365 | cd->owner = THIS_MODULE, | |
366 | cd->hash_size = NFS_DNS_HASHTBL_SIZE, | |
367 | cd->hash_table = tbl, | |
368 | cd->name = "dns_resolve", | |
369 | cd->cache_put = nfs_dns_ent_put, | |
370 | cd->cache_upcall = nfs_dns_upcall, | |
371 | cd->cache_parse = nfs_dns_parse, | |
372 | cd->cache_show = nfs_dns_show, | |
373 | cd->match = nfs_dns_match, | |
374 | cd->init = nfs_dns_ent_init, | |
375 | cd->update = nfs_dns_ent_update, | |
376 | cd->alloc = nfs_dns_ent_alloc, | |
377 | ||
378 | nfs_cache_init(cd); | |
379 | err = nfs_cache_register_net(net, cd); | |
380 | if (err) | |
381 | goto err_reg; | |
382 | nn->nfs_dns_resolve = cd; | |
383 | return 0; | |
9222b955 | 384 | |
1b340d01 SK |
385 | err_reg: |
386 | nfs_cache_destroy(cd); | |
387 | kfree(cd->hash_table); | |
388 | err_tbl: | |
389 | kfree(cd); | |
390 | err_cd: | |
391 | return err; | |
392 | } | |
393 | ||
394 | void nfs_dns_resolver_cache_destroy(struct net *net) | |
395 | { | |
396 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
397 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
398 | ||
399 | nfs_cache_unregister_net(net, cd); | |
400 | nfs_cache_destroy(cd); | |
401 | kfree(cd->hash_table); | |
402 | kfree(cd); | |
403 | } | |
404 | ||
9df69c81 SK |
405 | static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event, |
406 | void *ptr) | |
407 | { | |
408 | struct super_block *sb = ptr; | |
409 | struct net *net = sb->s_fs_info; | |
410 | struct nfs_net *nn = net_generic(net, nfs_net_id); | |
411 | struct cache_detail *cd = nn->nfs_dns_resolve; | |
412 | int ret = 0; | |
413 | ||
414 | if (cd == NULL) | |
415 | return 0; | |
416 | ||
417 | if (!try_module_get(THIS_MODULE)) | |
418 | return 0; | |
419 | ||
420 | switch (event) { | |
421 | case RPC_PIPEFS_MOUNT: | |
422 | ret = nfs_cache_register_sb(sb, cd); | |
423 | break; | |
424 | case RPC_PIPEFS_UMOUNT: | |
425 | nfs_cache_unregister_sb(sb, cd); | |
426 | break; | |
427 | default: | |
428 | ret = -ENOTSUPP; | |
429 | break; | |
430 | } | |
431 | module_put(THIS_MODULE); | |
432 | return ret; | |
433 | } | |
434 | ||
435 | static struct notifier_block nfs_dns_resolver_block = { | |
436 | .notifier_call = rpc_pipefs_event, | |
437 | }; | |
438 | ||
1b340d01 SK |
439 | int nfs_dns_resolver_init(void) |
440 | { | |
9df69c81 | 441 | return rpc_pipefs_notifier_register(&nfs_dns_resolver_block); |
e571cbf1 TM |
442 | } |
443 | ||
444 | void nfs_dns_resolver_destroy(void) | |
445 | { | |
9df69c81 | 446 | rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block); |
e571cbf1 | 447 | } |
c2e8139c | 448 | #endif |