Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6
[linux-2.6] / 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 static const int nfs_set_port_min = 0;
47 static const int nfs_set_port_max = 65535;
48
49 static int param_set_port(const char *val, struct kernel_param *kp)
50 {
51         char *endp;
52         int num = simple_strtol(val, &endp, 0);
53         if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
54                 return -EINVAL;
55         *((int *)kp->arg) = num;
56         return 0;
57 }
58
59 module_param_call(callback_tcpport, param_set_port, param_get_int,
60                  &nfs_callback_set_tcpport, 0644);
61
62 /*
63  * This is the NFSv4 callback kernel thread.
64  */
65 static int
66 nfs4_callback_svc(void *vrqstp)
67 {
68         int err, preverr = 0;
69         struct svc_rqst *rqstp = vrqstp;
70
71         set_freezable();
72
73         /*
74          * FIXME: do we really need to run this under the BKL? If so, please
75          * add a comment about what it's intended to protect.
76          */
77         lock_kernel();
78         while (!kthread_should_stop()) {
79                 /*
80                  * Listen for a request on the socket
81                  */
82                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
83                 if (err == -EAGAIN || err == -EINTR) {
84                         preverr = err;
85                         continue;
86                 }
87                 if (err < 0) {
88                         if (err != preverr) {
89                                 printk(KERN_WARNING "%s: unexpected error "
90                                         "from svc_recv (%d)\n", __func__, err);
91                                 preverr = err;
92                         }
93                         schedule_timeout_uninterruptible(HZ);
94                         continue;
95                 }
96                 preverr = err;
97                 svc_process(rqstp);
98         }
99         unlock_kernel();
100         return 0;
101 }
102
103 /*
104  * Prepare to bring up the NFSv4 callback service
105  */
106 struct svc_rqst *
107 nfs4_callback_up(struct svc_serv *serv)
108 {
109         int ret;
110
111         ret = svc_create_xprt(serv, "tcp", PF_INET,
112                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
113         if (ret <= 0)
114                 goto out_err;
115         nfs_callback_tcpport = ret;
116         dprintk("NFS: Callback listener port = %u (af %u)\n",
117                         nfs_callback_tcpport, PF_INET);
118
119 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
120         ret = svc_create_xprt(serv, "tcp", 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 #endif  /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
131
132         return svc_prepare_thread(serv, &serv->sv_pools[0]);
133
134 out_err:
135         if (ret == 0)
136                 ret = -ENOMEM;
137         return ERR_PTR(ret);
138 }
139
140 #if defined(CONFIG_NFS_V4_1)
141 /*
142  * The callback service for NFSv4.1 callbacks
143  */
144 static int
145 nfs41_callback_svc(void *vrqstp)
146 {
147         struct svc_rqst *rqstp = vrqstp;
148         struct svc_serv *serv = rqstp->rq_server;
149         struct rpc_rqst *req;
150         int error;
151         DEFINE_WAIT(wq);
152
153         set_freezable();
154
155         /*
156          * FIXME: do we really need to run this under the BKL? If so, please
157          * add a comment about what it's intended to protect.
158          */
159         lock_kernel();
160         while (!kthread_should_stop()) {
161                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
162                 spin_lock_bh(&serv->sv_cb_lock);
163                 if (!list_empty(&serv->sv_cb_list)) {
164                         req = list_first_entry(&serv->sv_cb_list,
165                                         struct rpc_rqst, rq_bc_list);
166                         list_del(&req->rq_bc_list);
167                         spin_unlock_bh(&serv->sv_cb_lock);
168                         dprintk("Invoking bc_svc_process()\n");
169                         error = bc_svc_process(serv, req, rqstp);
170                         dprintk("bc_svc_process() returned w/ error code= %d\n",
171                                 error);
172                 } else {
173                         spin_unlock_bh(&serv->sv_cb_lock);
174                         schedule();
175                 }
176                 finish_wait(&serv->sv_cb_waitq, &wq);
177         }
178         unlock_kernel();
179         return 0;
180 }
181
182 /*
183  * Bring up the NFSv4.1 callback service
184  */
185 struct svc_rqst *
186 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
187 {
188         struct svc_xprt *bc_xprt;
189         struct svc_rqst *rqstp = ERR_PTR(-ENOMEM);
190
191         dprintk("--> %s\n", __func__);
192         /* Create a svc_sock for the service */
193         bc_xprt = svc_sock_create(serv, xprt->prot);
194         if (!bc_xprt)
195                 goto out;
196
197         /*
198          * Save the svc_serv in the transport so that it can
199          * be referenced when the session backchannel is initialized
200          */
201         serv->bc_xprt = bc_xprt;
202         xprt->bc_serv = serv;
203
204         INIT_LIST_HEAD(&serv->sv_cb_list);
205         spin_lock_init(&serv->sv_cb_lock);
206         init_waitqueue_head(&serv->sv_cb_waitq);
207         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
208         if (IS_ERR(rqstp))
209                 svc_sock_destroy(bc_xprt);
210 out:
211         dprintk("--> %s return %p\n", __func__, rqstp);
212         return rqstp;
213 }
214
215 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
216                 struct svc_serv *serv, struct rpc_xprt *xprt,
217                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
218 {
219         if (minorversion) {
220                 *rqstpp = nfs41_callback_up(serv, xprt);
221                 *callback_svc = nfs41_callback_svc;
222         }
223         return minorversion;
224 }
225
226 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
227                 struct nfs_callback_data *cb_info)
228 {
229         if (minorversion)
230                 xprt->bc_serv = cb_info->serv;
231 }
232 #else
233 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
234                 struct svc_serv *serv, struct rpc_xprt *xprt,
235                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
236 {
237         return 0;
238 }
239
240 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
241                 struct nfs_callback_data *cb_info)
242 {
243 }
244 #endif /* CONFIG_NFS_V4_1 */
245
246 /*
247  * Bring up the callback thread if it is not already up.
248  */
249 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
250 {
251         struct svc_serv *serv = NULL;
252         struct svc_rqst *rqstp;
253         int (*callback_svc)(void *vrqstp);
254         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
255         char svc_name[12];
256         int ret = 0;
257         int minorversion_setup;
258
259         mutex_lock(&nfs_callback_mutex);
260         if (cb_info->users++ || cb_info->task != NULL) {
261                 nfs_callback_bc_serv(minorversion, xprt, cb_info);
262                 goto out;
263         }
264         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
265         if (!serv) {
266                 ret = -ENOMEM;
267                 goto out_err;
268         }
269
270         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
271                                         serv, xprt, &rqstp, &callback_svc);
272         if (!minorversion_setup) {
273                 /* v4.0 callback setup */
274                 rqstp = nfs4_callback_up(serv);
275                 callback_svc = nfs4_callback_svc;
276         }
277
278         if (IS_ERR(rqstp)) {
279                 ret = PTR_ERR(rqstp);
280                 goto out_err;
281         }
282
283         svc_sock_update_bufs(serv);
284
285         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
286         cb_info->serv = serv;
287         cb_info->rqst = rqstp;
288         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
289         if (IS_ERR(cb_info->task)) {
290                 ret = PTR_ERR(cb_info->task);
291                 svc_exit_thread(cb_info->rqst);
292                 cb_info->rqst = NULL;
293                 cb_info->task = NULL;
294                 goto out_err;
295         }
296 out:
297         /*
298          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
299          * svc_prepare_thread increments that. So we need to call svc_destroy
300          * on both success and failure so that the refcount is 1 when the
301          * thread exits.
302          */
303         if (serv)
304                 svc_destroy(serv);
305         mutex_unlock(&nfs_callback_mutex);
306         return ret;
307 out_err:
308         dprintk("NFS: Couldn't create callback socket or server thread; "
309                 "err = %d\n", ret);
310         cb_info->users--;
311         goto out;
312 }
313
314 /*
315  * Kill the callback thread if it's no longer being used.
316  */
317 void nfs_callback_down(int minorversion)
318 {
319         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
320
321         mutex_lock(&nfs_callback_mutex);
322         cb_info->users--;
323         if (cb_info->users == 0 && cb_info->task != NULL) {
324                 kthread_stop(cb_info->task);
325                 svc_exit_thread(cb_info->rqst);
326                 cb_info->serv = NULL;
327                 cb_info->rqst = NULL;
328                 cb_info->task = NULL;
329         }
330         mutex_unlock(&nfs_callback_mutex);
331 }
332
333 static int check_gss_callback_principal(struct nfs_client *clp,
334                                         struct svc_rqst *rqstp)
335 {
336         struct rpc_clnt *r = clp->cl_rpcclient;
337         char *p = svc_gss_principal(rqstp);
338
339         /*
340          * It might just be a normal user principal, in which case
341          * userspace won't bother to tell us the name at all.
342          */
343         if (p == NULL)
344                 return SVC_DENIED;
345
346         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
347
348         if (memcmp(p, "nfs@", 4) != 0)
349                 return SVC_DENIED;
350         p += 4;
351         if (strcmp(p, r->cl_server) != 0)
352                 return SVC_DENIED;
353         return SVC_OK;
354 }
355
356 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
357 {
358         struct nfs_client *clp;
359         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
360         int ret = SVC_OK;
361
362         /* Don't talk to strangers */
363         clp = nfs_find_client(svc_addr(rqstp), 4);
364         if (clp == NULL)
365                 return SVC_DROP;
366
367         dprintk("%s: %s NFSv4 callback!\n", __func__,
368                         svc_print_addr(rqstp, buf, sizeof(buf)));
369
370         switch (rqstp->rq_authop->flavour) {
371                 case RPC_AUTH_NULL:
372                         if (rqstp->rq_proc != CB_NULL)
373                                 ret = SVC_DENIED;
374                         break;
375                 case RPC_AUTH_UNIX:
376                         break;
377                 case RPC_AUTH_GSS:
378                         ret = check_gss_callback_principal(clp, rqstp);
379                         break;
380                 default:
381                         ret = SVC_DENIED;
382         }
383         nfs_put_client(clp);
384         return ret;
385 }
386
387 /*
388  * Define NFS4 callback program
389  */
390 static struct svc_version *nfs4_callback_version[] = {
391         [1] = &nfs4_callback_version1,
392 };
393
394 static struct svc_stat nfs4_callback_stats;
395
396 static struct svc_program nfs4_callback_program = {
397         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
398         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
399         .pg_vers = nfs4_callback_version,               /* version table */
400         .pg_name = "NFSv4 callback",                    /* service name */
401         .pg_class = "nfs",                              /* authentication class */
402         .pg_stats = &nfs4_callback_stats,
403         .pg_authenticate = nfs_callback_authenticate,
404 };