nfs41: add support for callback with RPC version number 4
[linux-2.6.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, 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
62 static int param_get_portnr(char *buffer, struct kernel_param *kp)
63 {
64         return param_get_uint(buffer, kp);
65 }
66 #define param_check_portnr(name, p) __param_check(name, p, unsigned int);
67
68 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
69
70 /*
71  * This is the NFSv4 callback kernel thread.
72  */
73 static int
74 nfs4_callback_svc(void *vrqstp)
75 {
76         int err, preverr = 0;
77         struct svc_rqst *rqstp = vrqstp;
78
79         set_freezable();
80
81         while (!kthread_should_stop()) {
82                 /*
83                  * Listen for a request on the socket
84                  */
85                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
86                 if (err == -EAGAIN || err == -EINTR) {
87                         preverr = err;
88                         continue;
89                 }
90                 if (err < 0) {
91                         if (err != preverr) {
92                                 printk(KERN_WARNING "%s: unexpected error "
93                                         "from svc_recv (%d)\n", __func__, err);
94                                 preverr = err;
95                         }
96                         schedule_timeout_uninterruptible(HZ);
97                         continue;
98                 }
99                 preverr = err;
100                 svc_process(rqstp);
101         }
102         return 0;
103 }
104
105 /*
106  * Prepare to bring up the NFSv4 callback service
107  */
108 struct svc_rqst *
109 nfs4_callback_up(struct svc_serv *serv)
110 {
111         int ret;
112
113         ret = svc_create_xprt(serv, "tcp", PF_INET,
114                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
115         if (ret <= 0)
116                 goto out_err;
117         nfs_callback_tcpport = ret;
118         dprintk("NFS: Callback listener port = %u (af %u)\n",
119                         nfs_callback_tcpport, PF_INET);
120
121 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
122         ret = svc_create_xprt(serv, "tcp", PF_INET6,
123                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
124         if (ret > 0) {
125                 nfs_callback_tcpport6 = ret;
126                 dprintk("NFS: Callback listener port = %u (af %u)\n",
127                                 nfs_callback_tcpport6, PF_INET6);
128         } else if (ret == -EAFNOSUPPORT)
129                 ret = 0;
130         else
131                 goto out_err;
132 #endif  /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
133
134         return svc_prepare_thread(serv, &serv->sv_pools[0]);
135
136 out_err:
137         if (ret == 0)
138                 ret = -ENOMEM;
139         return ERR_PTR(ret);
140 }
141
142 #if defined(CONFIG_NFS_V4_1)
143 /*
144  * The callback service for NFSv4.1 callbacks
145  */
146 static int
147 nfs41_callback_svc(void *vrqstp)
148 {
149         struct svc_rqst *rqstp = vrqstp;
150         struct svc_serv *serv = rqstp->rq_server;
151         struct rpc_rqst *req;
152         int error;
153         DEFINE_WAIT(wq);
154
155         set_freezable();
156
157         while (!kthread_should_stop()) {
158                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
159                 spin_lock_bh(&serv->sv_cb_lock);
160                 if (!list_empty(&serv->sv_cb_list)) {
161                         req = list_first_entry(&serv->sv_cb_list,
162                                         struct rpc_rqst, rq_bc_list);
163                         list_del(&req->rq_bc_list);
164                         spin_unlock_bh(&serv->sv_cb_lock);
165                         dprintk("Invoking bc_svc_process()\n");
166                         error = bc_svc_process(serv, req, rqstp);
167                         dprintk("bc_svc_process() returned w/ error code= %d\n",
168                                 error);
169                 } else {
170                         spin_unlock_bh(&serv->sv_cb_lock);
171                         schedule();
172                 }
173                 finish_wait(&serv->sv_cb_waitq, &wq);
174         }
175         return 0;
176 }
177
178 /*
179  * Bring up the NFSv4.1 callback service
180  */
181 struct svc_rqst *
182 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
183 {
184         struct svc_xprt *bc_xprt;
185         struct svc_rqst *rqstp = ERR_PTR(-ENOMEM);
186
187         dprintk("--> %s\n", __func__);
188         /* Create a svc_sock for the service */
189         bc_xprt = svc_sock_create(serv, xprt->prot);
190         if (!bc_xprt)
191                 goto out;
192
193         /*
194          * Save the svc_serv in the transport so that it can
195          * be referenced when the session backchannel is initialized
196          */
197         serv->bc_xprt = bc_xprt;
198         xprt->bc_serv = serv;
199
200         INIT_LIST_HEAD(&serv->sv_cb_list);
201         spin_lock_init(&serv->sv_cb_lock);
202         init_waitqueue_head(&serv->sv_cb_waitq);
203         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
204         if (IS_ERR(rqstp))
205                 svc_sock_destroy(bc_xprt);
206 out:
207         dprintk("--> %s return %p\n", __func__, rqstp);
208         return rqstp;
209 }
210
211 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
212                 struct svc_serv *serv, struct rpc_xprt *xprt,
213                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
214 {
215         if (minorversion) {
216                 *rqstpp = nfs41_callback_up(serv, xprt);
217                 *callback_svc = nfs41_callback_svc;
218         }
219         return minorversion;
220 }
221
222 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
223                 struct nfs_callback_data *cb_info)
224 {
225         if (minorversion)
226                 xprt->bc_serv = cb_info->serv;
227 }
228 #else
229 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
230                 struct svc_serv *serv, struct rpc_xprt *xprt,
231                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
232 {
233         return 0;
234 }
235
236 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
237                 struct nfs_callback_data *cb_info)
238 {
239 }
240 #endif /* CONFIG_NFS_V4_1 */
241
242 /*
243  * Bring up the callback thread if it is not already up.
244  */
245 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
246 {
247         struct svc_serv *serv = NULL;
248         struct svc_rqst *rqstp;
249         int (*callback_svc)(void *vrqstp);
250         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
251         char svc_name[12];
252         int ret = 0;
253         int minorversion_setup;
254
255         mutex_lock(&nfs_callback_mutex);
256         if (cb_info->users++ || cb_info->task != NULL) {
257                 nfs_callback_bc_serv(minorversion, xprt, cb_info);
258                 goto out;
259         }
260         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
261         if (!serv) {
262                 ret = -ENOMEM;
263                 goto out_err;
264         }
265
266         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
267                                         serv, xprt, &rqstp, &callback_svc);
268         if (!minorversion_setup) {
269                 /* v4.0 callback setup */
270                 rqstp = nfs4_callback_up(serv);
271                 callback_svc = nfs4_callback_svc;
272         }
273
274         if (IS_ERR(rqstp)) {
275                 ret = PTR_ERR(rqstp);
276                 goto out_err;
277         }
278
279         svc_sock_update_bufs(serv);
280
281         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
282         cb_info->serv = serv;
283         cb_info->rqst = rqstp;
284         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
285         if (IS_ERR(cb_info->task)) {
286                 ret = PTR_ERR(cb_info->task);
287                 svc_exit_thread(cb_info->rqst);
288                 cb_info->rqst = NULL;
289                 cb_info->task = NULL;
290                 goto out_err;
291         }
292 out:
293         /*
294          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
295          * svc_prepare_thread increments that. So we need to call svc_destroy
296          * on both success and failure so that the refcount is 1 when the
297          * thread exits.
298          */
299         if (serv)
300                 svc_destroy(serv);
301         mutex_unlock(&nfs_callback_mutex);
302         return ret;
303 out_err:
304         dprintk("NFS: Couldn't create callback socket or server thread; "
305                 "err = %d\n", ret);
306         cb_info->users--;
307         goto out;
308 }
309
310 /*
311  * Kill the callback thread if it's no longer being used.
312  */
313 void nfs_callback_down(int minorversion)
314 {
315         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
316
317         mutex_lock(&nfs_callback_mutex);
318         cb_info->users--;
319         if (cb_info->users == 0 && cb_info->task != NULL) {
320                 kthread_stop(cb_info->task);
321                 svc_exit_thread(cb_info->rqst);
322                 cb_info->serv = NULL;
323                 cb_info->rqst = NULL;
324                 cb_info->task = NULL;
325         }
326         mutex_unlock(&nfs_callback_mutex);
327 }
328
329 static int check_gss_callback_principal(struct nfs_client *clp,
330                                         struct svc_rqst *rqstp)
331 {
332         struct rpc_clnt *r = clp->cl_rpcclient;
333         char *p = svc_gss_principal(rqstp);
334
335         /*
336          * It might just be a normal user principal, in which case
337          * userspace won't bother to tell us the name at all.
338          */
339         if (p == NULL)
340                 return SVC_DENIED;
341
342         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
343
344         if (memcmp(p, "nfs@", 4) != 0)
345                 return SVC_DENIED;
346         p += 4;
347         if (strcmp(p, r->cl_server) != 0)
348                 return SVC_DENIED;
349         return SVC_OK;
350 }
351
352 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
353 {
354         struct nfs_client *clp;
355         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
356         int ret = SVC_OK;
357
358         /* Don't talk to strangers */
359         clp = nfs_find_client(svc_addr(rqstp), 4);
360         if (clp == NULL)
361                 return SVC_DROP;
362
363         dprintk("%s: %s NFSv4 callback!\n", __func__,
364                         svc_print_addr(rqstp, buf, sizeof(buf)));
365
366         switch (rqstp->rq_authop->flavour) {
367                 case RPC_AUTH_NULL:
368                         if (rqstp->rq_proc != CB_NULL)
369                                 ret = SVC_DENIED;
370                         break;
371                 case RPC_AUTH_UNIX:
372                         break;
373                 case RPC_AUTH_GSS:
374                         ret = check_gss_callback_principal(clp, rqstp);
375                         break;
376                 default:
377                         ret = SVC_DENIED;
378         }
379         nfs_put_client(clp);
380         return ret;
381 }
382
383 /*
384  * Define NFS4 callback program
385  */
386 static struct svc_version *nfs4_callback_version[] = {
387         [1] = &nfs4_callback_version1,
388         [4] = &nfs4_callback_version4,
389 };
390
391 static struct svc_stat nfs4_callback_stats;
392
393 static struct svc_program nfs4_callback_program = {
394         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
395         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
396         .pg_vers = nfs4_callback_version,               /* version table */
397         .pg_name = "NFSv4 callback",                    /* service name */
398         .pg_class = "nfs",                              /* authentication class */
399         .pg_stats = &nfs4_callback_stats,
400         .pg_authenticate = nfs_callback_authenticate,
401 };