aeec017fe814acbdf17947a68553765a335359ae
[linux-3.10.git] / fs / nfs / callback.c
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 };