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1 | /* | |
2 | * linux/fs/nfs/callback.c | |
3 | * | |
4 | * Copyright (C) 2004 Trond Myklebust | |
5 | * | |
6 | * NFSv4 callback handling | |
7 | */ | |
8 | ||
9 | #include <linux/completion.h> | |
10 | #include <linux/ip.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/smp_lock.h> | |
13 | #include <linux/sunrpc/svc.h> | |
14 | #include <linux/sunrpc/svcsock.h> | |
15 | #include <linux/nfs_fs.h> | |
16 | #include <linux/mutex.h> | |
17 | #include <linux/freezer.h> | |
18 | #include <linux/kthread.h> | |
19 | #include <linux/sunrpc/svcauth_gss.h> | |
20 | #if defined(CONFIG_NFS_V4_1) | |
21 | #include <linux/sunrpc/bc_xprt.h> | |
22 | #endif | |
23 | ||
24 | #include <net/inet_sock.h> | |
25 | ||
26 | #include "nfs4_fs.h" | |
27 | #include "callback.h" | |
28 | #include "internal.h" | |
29 | ||
30 | #define NFSDBG_FACILITY NFSDBG_CALLBACK | |
31 | ||
32 | struct nfs_callback_data { | |
33 | unsigned int users; | |
34 | struct svc_serv *serv; | |
35 | struct svc_rqst *rqst; | |
36 | struct task_struct *task; | |
37 | }; | |
38 | ||
39 | static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1]; | |
40 | static DEFINE_MUTEX(nfs_callback_mutex); | |
41 | static struct svc_program nfs4_callback_program; | |
42 | ||
43 | unsigned int nfs_callback_set_tcpport; | |
44 | unsigned short nfs_callback_tcpport; | |
45 | unsigned short nfs_callback_tcpport6; | |
46 | #define NFS_CALLBACK_MAXPORTNR (65535U) | |
47 | ||
48 | static int param_set_portnr(const char *val, const struct kernel_param *kp) | |
49 | { | |
50 | unsigned long num; | |
51 | int ret; | |
52 | ||
53 | if (!val) | |
54 | return -EINVAL; | |
55 | ret = strict_strtoul(val, 0, &num); | |
56 | if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR) | |
57 | return -EINVAL; | |
58 | *((unsigned int *)kp->arg) = num; | |
59 | return 0; | |
60 | } | |
61 | static struct kernel_param_ops param_ops_portnr = { | |
62 | .set = param_set_portnr, | |
63 | .get = param_get_uint, | |
64 | }; | |
65 | #define param_check_portnr(name, p) __param_check(name, p, unsigned int); | |
66 | ||
67 | module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644); | |
68 | ||
69 | /* | |
70 | * This is the NFSv4 callback kernel thread. | |
71 | */ | |
72 | static int | |
73 | nfs4_callback_svc(void *vrqstp) | |
74 | { | |
75 | int err, preverr = 0; | |
76 | struct svc_rqst *rqstp = vrqstp; | |
77 | ||
78 | set_freezable(); | |
79 | ||
80 | while (!kthread_should_stop()) { | |
81 | /* | |
82 | * Listen for a request on the socket | |
83 | */ | |
84 | err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); | |
85 | if (err == -EAGAIN || err == -EINTR) { | |
86 | preverr = err; | |
87 | continue; | |
88 | } | |
89 | if (err < 0) { | |
90 | if (err != preverr) { | |
91 | printk(KERN_WARNING "%s: unexpected error " | |
92 | "from svc_recv (%d)\n", __func__, err); | |
93 | preverr = err; | |
94 | } | |
95 | schedule_timeout_uninterruptible(HZ); | |
96 | continue; | |
97 | } | |
98 | preverr = err; | |
99 | svc_process(rqstp); | |
100 | } | |
101 | return 0; | |
102 | } | |
103 | ||
104 | /* | |
105 | * Prepare to bring up the NFSv4 callback service | |
106 | */ | |
107 | struct svc_rqst * | |
108 | nfs4_callback_up(struct svc_serv *serv) | |
109 | { | |
110 | int ret; | |
111 | ||
112 | ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET, | |
113 | nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); | |
114 | if (ret <= 0) | |
115 | goto out_err; | |
116 | nfs_callback_tcpport = ret; | |
117 | dprintk("NFS: Callback listener port = %u (af %u)\n", | |
118 | nfs_callback_tcpport, PF_INET); | |
119 | ||
120 | ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET6, | |
121 | nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); | |
122 | if (ret > 0) { | |
123 | nfs_callback_tcpport6 = ret; | |
124 | dprintk("NFS: Callback listener port = %u (af %u)\n", | |
125 | nfs_callback_tcpport6, PF_INET6); | |
126 | } else if (ret == -EAFNOSUPPORT) | |
127 | ret = 0; | |
128 | else | |
129 | goto out_err; | |
130 | ||
131 | return svc_prepare_thread(serv, &serv->sv_pools[0]); | |
132 | ||
133 | out_err: | |
134 | if (ret == 0) | |
135 | ret = -ENOMEM; | |
136 | return ERR_PTR(ret); | |
137 | } | |
138 | ||
139 | #if defined(CONFIG_NFS_V4_1) | |
140 | /* | |
141 | * The callback service for NFSv4.1 callbacks | |
142 | */ | |
143 | static int | |
144 | nfs41_callback_svc(void *vrqstp) | |
145 | { | |
146 | struct svc_rqst *rqstp = vrqstp; | |
147 | struct svc_serv *serv = rqstp->rq_server; | |
148 | struct rpc_rqst *req; | |
149 | int error; | |
150 | DEFINE_WAIT(wq); | |
151 | ||
152 | set_freezable(); | |
153 | ||
154 | while (!kthread_should_stop()) { | |
155 | prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); | |
156 | spin_lock_bh(&serv->sv_cb_lock); | |
157 | if (!list_empty(&serv->sv_cb_list)) { | |
158 | req = list_first_entry(&serv->sv_cb_list, | |
159 | struct rpc_rqst, rq_bc_list); | |
160 | list_del(&req->rq_bc_list); | |
161 | spin_unlock_bh(&serv->sv_cb_lock); | |
162 | dprintk("Invoking bc_svc_process()\n"); | |
163 | error = bc_svc_process(serv, req, rqstp); | |
164 | dprintk("bc_svc_process() returned w/ error code= %d\n", | |
165 | error); | |
166 | } else { | |
167 | spin_unlock_bh(&serv->sv_cb_lock); | |
168 | schedule(); | |
169 | } | |
170 | finish_wait(&serv->sv_cb_waitq, &wq); | |
171 | } | |
172 | return 0; | |
173 | } | |
174 | ||
175 | /* | |
176 | * Bring up the NFSv4.1 callback service | |
177 | */ | |
178 | struct svc_rqst * | |
179 | nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) | |
180 | { | |
181 | struct svc_xprt *bc_xprt; | |
182 | struct svc_rqst *rqstp = ERR_PTR(-ENOMEM); | |
183 | ||
184 | dprintk("--> %s\n", __func__); | |
185 | /* Create a svc_sock for the service */ | |
186 | bc_xprt = svc_sock_create(serv, xprt->prot); | |
187 | if (!bc_xprt) | |
188 | goto out; | |
189 | ||
190 | /* | |
191 | * Save the svc_serv in the transport so that it can | |
192 | * be referenced when the session backchannel is initialized | |
193 | */ | |
194 | serv->bc_xprt = bc_xprt; | |
195 | xprt->bc_serv = serv; | |
196 | ||
197 | INIT_LIST_HEAD(&serv->sv_cb_list); | |
198 | spin_lock_init(&serv->sv_cb_lock); | |
199 | init_waitqueue_head(&serv->sv_cb_waitq); | |
200 | rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]); | |
201 | if (IS_ERR(rqstp)) | |
202 | svc_sock_destroy(bc_xprt); | |
203 | out: | |
204 | dprintk("--> %s return %p\n", __func__, rqstp); | |
205 | return rqstp; | |
206 | } | |
207 | ||
208 | static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, | |
209 | struct svc_serv *serv, struct rpc_xprt *xprt, | |
210 | struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) | |
211 | { | |
212 | if (minorversion) { | |
213 | *rqstpp = nfs41_callback_up(serv, xprt); | |
214 | *callback_svc = nfs41_callback_svc; | |
215 | } | |
216 | return minorversion; | |
217 | } | |
218 | ||
219 | static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, | |
220 | struct nfs_callback_data *cb_info) | |
221 | { | |
222 | if (minorversion) | |
223 | xprt->bc_serv = cb_info->serv; | |
224 | } | |
225 | #else | |
226 | static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, | |
227 | struct svc_serv *serv, struct rpc_xprt *xprt, | |
228 | struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) | |
229 | { | |
230 | return 0; | |
231 | } | |
232 | ||
233 | static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, | |
234 | struct nfs_callback_data *cb_info) | |
235 | { | |
236 | } | |
237 | #endif /* CONFIG_NFS_V4_1 */ | |
238 | ||
239 | /* | |
240 | * Bring up the callback thread if it is not already up. | |
241 | */ | |
242 | int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) | |
243 | { | |
244 | struct svc_serv *serv = NULL; | |
245 | struct svc_rqst *rqstp; | |
246 | int (*callback_svc)(void *vrqstp); | |
247 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; | |
248 | char svc_name[12]; | |
249 | int ret = 0; | |
250 | int minorversion_setup; | |
251 | ||
252 | mutex_lock(&nfs_callback_mutex); | |
253 | if (cb_info->users++ || cb_info->task != NULL) { | |
254 | nfs_callback_bc_serv(minorversion, xprt, cb_info); | |
255 | goto out; | |
256 | } | |
257 | serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); | |
258 | if (!serv) { | |
259 | ret = -ENOMEM; | |
260 | goto out_err; | |
261 | } | |
262 | ||
263 | minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion, | |
264 | serv, xprt, &rqstp, &callback_svc); | |
265 | if (!minorversion_setup) { | |
266 | /* v4.0 callback setup */ | |
267 | rqstp = nfs4_callback_up(serv); | |
268 | callback_svc = nfs4_callback_svc; | |
269 | } | |
270 | ||
271 | if (IS_ERR(rqstp)) { | |
272 | ret = PTR_ERR(rqstp); | |
273 | goto out_err; | |
274 | } | |
275 | ||
276 | svc_sock_update_bufs(serv); | |
277 | ||
278 | sprintf(svc_name, "nfsv4.%u-svc", minorversion); | |
279 | cb_info->serv = serv; | |
280 | cb_info->rqst = rqstp; | |
281 | cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); | |
282 | if (IS_ERR(cb_info->task)) { | |
283 | ret = PTR_ERR(cb_info->task); | |
284 | svc_exit_thread(cb_info->rqst); | |
285 | cb_info->rqst = NULL; | |
286 | cb_info->task = NULL; | |
287 | goto out_err; | |
288 | } | |
289 | out: | |
290 | /* | |
291 | * svc_create creates the svc_serv with sv_nrthreads == 1, and then | |
292 | * svc_prepare_thread increments that. So we need to call svc_destroy | |
293 | * on both success and failure so that the refcount is 1 when the | |
294 | * thread exits. | |
295 | */ | |
296 | if (serv) | |
297 | svc_destroy(serv); | |
298 | mutex_unlock(&nfs_callback_mutex); | |
299 | return ret; | |
300 | out_err: | |
301 | dprintk("NFS: Couldn't create callback socket or server thread; " | |
302 | "err = %d\n", ret); | |
303 | cb_info->users--; | |
304 | goto out; | |
305 | } | |
306 | ||
307 | /* | |
308 | * Kill the callback thread if it's no longer being used. | |
309 | */ | |
310 | void nfs_callback_down(int minorversion) | |
311 | { | |
312 | struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; | |
313 | ||
314 | mutex_lock(&nfs_callback_mutex); | |
315 | cb_info->users--; | |
316 | if (cb_info->users == 0 && cb_info->task != NULL) { | |
317 | kthread_stop(cb_info->task); | |
318 | svc_exit_thread(cb_info->rqst); | |
319 | cb_info->serv = NULL; | |
320 | cb_info->rqst = NULL; | |
321 | cb_info->task = NULL; | |
322 | } | |
323 | mutex_unlock(&nfs_callback_mutex); | |
324 | } | |
325 | ||
326 | static int check_gss_callback_principal(struct nfs_client *clp, | |
327 | struct svc_rqst *rqstp) | |
328 | { | |
329 | struct rpc_clnt *r = clp->cl_rpcclient; | |
330 | char *p = svc_gss_principal(rqstp); | |
331 | ||
332 | /* | |
333 | * It might just be a normal user principal, in which case | |
334 | * userspace won't bother to tell us the name at all. | |
335 | */ | |
336 | if (p == NULL) | |
337 | return SVC_DENIED; | |
338 | ||
339 | /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ | |
340 | ||
341 | if (memcmp(p, "nfs@", 4) != 0) | |
342 | return SVC_DENIED; | |
343 | p += 4; | |
344 | if (strcmp(p, r->cl_server) != 0) | |
345 | return SVC_DENIED; | |
346 | return SVC_OK; | |
347 | } | |
348 | ||
349 | static int nfs_callback_authenticate(struct svc_rqst *rqstp) | |
350 | { | |
351 | struct nfs_client *clp; | |
352 | RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); | |
353 | int ret = SVC_OK; | |
354 | ||
355 | /* Don't talk to strangers */ | |
356 | clp = nfs_find_client(svc_addr(rqstp), 4); | |
357 | if (clp == NULL) | |
358 | return SVC_DROP; | |
359 | ||
360 | dprintk("%s: %s NFSv4 callback!\n", __func__, | |
361 | svc_print_addr(rqstp, buf, sizeof(buf))); | |
362 | ||
363 | switch (rqstp->rq_authop->flavour) { | |
364 | case RPC_AUTH_NULL: | |
365 | if (rqstp->rq_proc != CB_NULL) | |
366 | ret = SVC_DENIED; | |
367 | break; | |
368 | case RPC_AUTH_UNIX: | |
369 | break; | |
370 | case RPC_AUTH_GSS: | |
371 | ret = check_gss_callback_principal(clp, rqstp); | |
372 | break; | |
373 | default: | |
374 | ret = SVC_DENIED; | |
375 | } | |
376 | nfs_put_client(clp); | |
377 | return ret; | |
378 | } | |
379 | ||
380 | /* | |
381 | * Define NFS4 callback program | |
382 | */ | |
383 | static struct svc_version *nfs4_callback_version[] = { | |
384 | [1] = &nfs4_callback_version1, | |
385 | [4] = &nfs4_callback_version4, | |
386 | }; | |
387 | ||
388 | static struct svc_stat nfs4_callback_stats; | |
389 | ||
390 | static struct svc_program nfs4_callback_program = { | |
391 | .pg_prog = NFS4_CALLBACK, /* RPC service number */ | |
392 | .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ | |
393 | .pg_vers = nfs4_callback_version, /* version table */ | |
394 | .pg_name = "NFSv4 callback", /* service name */ | |
395 | .pg_class = "nfs", /* authentication class */ | |
396 | .pg_stats = &nfs4_callback_stats, | |
397 | .pg_authenticate = nfs_callback_authenticate, | |
398 | }; |