Root/
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 | |
9 | #ifdef CONFIG_NFS_USE_KERNEL_DNS |
10 | |
11 | #include <linux/sunrpc/clnt.h> |
12 | #include <linux/dns_resolver.h> |
13 | |
14 | ssize_t nfs_dns_resolve_name(char *name, size_t namelen, |
15 | 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 | |
32 | #include <linux/hash.h> |
33 | #include <linux/string.h> |
34 | #include <linux/kmod.h> |
35 | #include <linux/slab.h> |
36 | #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> |
43 | |
44 | #include "dns_resolve.h" |
45 | #include "cache_lib.h" |
46 | |
47 | #define NFS_DNS_HASHBITS 4 |
48 | #define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) |
49 | |
50 | static struct cache_head *nfs_dns_table[NFS_DNS_HASHTBL_SIZE]; |
51 | |
52 | struct 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 | |
63 | static 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 | |
76 | static 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; |
89 | nfs_dns_ent_update(cnew, ckey); |
90 | } else { |
91 | new->namelen = 0; |
92 | new->addrlen = 0; |
93 | } |
94 | } |
95 | |
96 | static 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 | |
105 | static 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 | |
118 | static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key) |
119 | { |
120 | return hash_str(key->hostname, NFS_DNS_HASHBITS); |
121 | } |
122 | |
123 | static 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 | |
133 | static 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 | |
145 | static 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 | |
159 | static 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); |
170 | ttl = item->h.expiry_time - seconds_since_boot(); |
171 | 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 | |
185 | static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd, |
186 | 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 | |
198 | static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd, |
199 | 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 | |
212 | static 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; |
242 | key.h.expiry_time = ttl + seconds_since_boot(); |
243 | |
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); |
258 | out: |
259 | return ret; |
260 | } |
261 | |
262 | static struct cache_detail nfs_dns_resolve = { |
263 | .owner = THIS_MODULE, |
264 | .hash_size = NFS_DNS_HASHTBL_SIZE, |
265 | .hash_table = nfs_dns_table, |
266 | .name = "dns_resolve", |
267 | .cache_put = nfs_dns_ent_put, |
268 | .cache_upcall = nfs_dns_upcall, |
269 | .cache_parse = nfs_dns_parse, |
270 | .cache_show = nfs_dns_show, |
271 | .match = nfs_dns_match, |
272 | .init = nfs_dns_ent_init, |
273 | .update = nfs_dns_ent_update, |
274 | .alloc = nfs_dns_ent_alloc, |
275 | }; |
276 | |
277 | static int do_cache_lookup(struct cache_detail *cd, |
278 | struct nfs_dns_ent *key, |
279 | struct nfs_dns_ent **item, |
280 | struct nfs_cache_defer_req *dreq) |
281 | { |
282 | int ret = -ENOMEM; |
283 | |
284 | *item = nfs_dns_lookup(cd, key); |
285 | if (*item) { |
286 | ret = cache_check(cd, &(*item)->h, &dreq->req); |
287 | if (ret) |
288 | *item = NULL; |
289 | } |
290 | return ret; |
291 | } |
292 | |
293 | static int do_cache_lookup_nowait(struct cache_detail *cd, |
294 | struct nfs_dns_ent *key, |
295 | struct nfs_dns_ent **item) |
296 | { |
297 | int ret = -ENOMEM; |
298 | |
299 | *item = nfs_dns_lookup(cd, key); |
300 | if (!*item) |
301 | goto out_err; |
302 | ret = -ETIMEDOUT; |
303 | if (!test_bit(CACHE_VALID, &(*item)->h.flags) |
304 | || (*item)->h.expiry_time < seconds_since_boot() |
305 | || cd->flush_time > (*item)->h.last_refresh) |
306 | goto out_put; |
307 | ret = -ENOENT; |
308 | if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags)) |
309 | goto out_put; |
310 | return 0; |
311 | out_put: |
312 | cache_put(&(*item)->h, cd); |
313 | out_err: |
314 | *item = NULL; |
315 | return ret; |
316 | } |
317 | |
318 | static int do_cache_lookup_wait(struct cache_detail *cd, |
319 | struct nfs_dns_ent *key, |
320 | struct nfs_dns_ent **item) |
321 | { |
322 | struct nfs_cache_defer_req *dreq; |
323 | int ret = -ENOMEM; |
324 | |
325 | dreq = nfs_cache_defer_req_alloc(); |
326 | if (!dreq) |
327 | goto out; |
328 | ret = do_cache_lookup(cd, key, item, dreq); |
329 | if (ret == -EAGAIN) { |
330 | ret = nfs_cache_wait_for_upcall(dreq); |
331 | if (!ret) |
332 | ret = do_cache_lookup_nowait(cd, key, item); |
333 | } |
334 | nfs_cache_defer_req_put(dreq); |
335 | out: |
336 | return ret; |
337 | } |
338 | |
339 | ssize_t nfs_dns_resolve_name(char *name, size_t namelen, |
340 | struct sockaddr *sa, size_t salen) |
341 | { |
342 | struct nfs_dns_ent key = { |
343 | .hostname = name, |
344 | .namelen = namelen, |
345 | }; |
346 | struct nfs_dns_ent *item = NULL; |
347 | ssize_t ret; |
348 | |
349 | ret = do_cache_lookup_wait(&nfs_dns_resolve, &key, &item); |
350 | if (ret == 0) { |
351 | if (salen >= item->addrlen) { |
352 | memcpy(sa, &item->addr, item->addrlen); |
353 | ret = item->addrlen; |
354 | } else |
355 | ret = -EOVERFLOW; |
356 | cache_put(&item->h, &nfs_dns_resolve); |
357 | } else if (ret == -ENOENT) |
358 | ret = -ESRCH; |
359 | return ret; |
360 | } |
361 | |
362 | int nfs_dns_resolver_init(void) |
363 | { |
364 | return nfs_cache_register(&nfs_dns_resolve); |
365 | } |
366 | |
367 | void nfs_dns_resolver_destroy(void) |
368 | { |
369 | nfs_cache_unregister(&nfs_dns_resolve); |
370 | } |
371 | |
372 | #endif |
373 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9