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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/sunrpc/svc.h>
13#include <linux/sunrpc/svcsock.h>
14#include <linux/nfs_fs.h>
15#include <linux/mutex.h>
16#include <linux/freezer.h>
17#include <linux/kthread.h>
18#include <linux/sunrpc/svcauth_gss.h>
19#include <linux/sunrpc/bc_xprt.h>
20
21#include <net/inet_sock.h>
22
23#include "nfs4_fs.h"
24#include "callback.h"
25#include "internal.h"
26
27#define NFSDBG_FACILITY NFSDBG_CALLBACK
28
29struct nfs_callback_data {
30 unsigned int users;
31 struct svc_serv *serv;
32 struct svc_rqst *rqst;
33 struct task_struct *task;
34};
35
36static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
37static DEFINE_MUTEX(nfs_callback_mutex);
38static struct svc_program nfs4_callback_program;
39
40unsigned int nfs_callback_set_tcpport;
41unsigned short nfs_callback_tcpport;
42unsigned short nfs_callback_tcpport6;
43#define NFS_CALLBACK_MAXPORTNR (65535U)
44
45static int param_set_portnr(const char *val, const struct kernel_param *kp)
46{
47 unsigned long num;
48 int ret;
49
50 if (!val)
51 return -EINVAL;
52 ret = strict_strtoul(val, 0, &num);
53 if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR)
54 return -EINVAL;
55 *((unsigned int *)kp->arg) = num;
56 return 0;
57}
58static struct kernel_param_ops param_ops_portnr = {
59 .set = param_set_portnr,
60 .get = param_get_uint,
61};
62#define param_check_portnr(name, p) __param_check(name, p, unsigned int);
63
64module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
65
66/*
67 * This is the NFSv4 callback kernel thread.
68 */
69static int
70nfs4_callback_svc(void *vrqstp)
71{
72 int err, preverr = 0;
73 struct svc_rqst *rqstp = vrqstp;
74
75 set_freezable();
76
77 while (!kthread_should_stop()) {
78 /*
79 * Listen for a request on the socket
80 */
81 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
82 if (err == -EAGAIN || err == -EINTR) {
83 preverr = err;
84 continue;
85 }
86 if (err < 0) {
87 if (err != preverr) {
88 printk(KERN_WARNING "NFS: %s: unexpected error "
89 "from svc_recv (%d)\n", __func__, err);
90 preverr = err;
91 }
92 schedule_timeout_uninterruptible(HZ);
93 continue;
94 }
95 preverr = err;
96 svc_process(rqstp);
97 }
98 return 0;
99}
100
101/*
102 * Prepare to bring up the NFSv4 callback service
103 */
104static struct svc_rqst *
105nfs4_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
106{
107 int ret;
108
109 ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET,
110 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
111 if (ret <= 0)
112 goto out_err;
113 nfs_callback_tcpport = ret;
114 dprintk("NFS: Callback listener port = %u (af %u)\n",
115 nfs_callback_tcpport, PF_INET);
116
117 ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET6,
118 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
119 if (ret > 0) {
120 nfs_callback_tcpport6 = ret;
121 dprintk("NFS: Callback listener port = %u (af %u)\n",
122 nfs_callback_tcpport6, PF_INET6);
123 } else if (ret == -EAFNOSUPPORT)
124 ret = 0;
125 else
126 goto out_err;
127
128 return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
129
130out_err:
131 if (ret == 0)
132 ret = -ENOMEM;
133 return ERR_PTR(ret);
134}
135
136#if defined(CONFIG_NFS_V4_1)
137/*
138 * The callback service for NFSv4.1 callbacks
139 */
140static int
141nfs41_callback_svc(void *vrqstp)
142{
143 struct svc_rqst *rqstp = vrqstp;
144 struct svc_serv *serv = rqstp->rq_server;
145 struct rpc_rqst *req;
146 int error;
147 DEFINE_WAIT(wq);
148
149 set_freezable();
150
151 while (!kthread_should_stop()) {
152 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
153 spin_lock_bh(&serv->sv_cb_lock);
154 if (!list_empty(&serv->sv_cb_list)) {
155 req = list_first_entry(&serv->sv_cb_list,
156 struct rpc_rqst, rq_bc_list);
157 list_del(&req->rq_bc_list);
158 spin_unlock_bh(&serv->sv_cb_lock);
159 dprintk("Invoking bc_svc_process()\n");
160 error = bc_svc_process(serv, req, rqstp);
161 dprintk("bc_svc_process() returned w/ error code= %d\n",
162 error);
163 } else {
164 spin_unlock_bh(&serv->sv_cb_lock);
165 schedule();
166 }
167 finish_wait(&serv->sv_cb_waitq, &wq);
168 }
169 return 0;
170}
171
172/*
173 * Bring up the NFSv4.1 callback service
174 */
175static struct svc_rqst *
176nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
177{
178 struct svc_rqst *rqstp;
179 int ret;
180
181 /*
182 * Create an svc_sock for the back channel service that shares the
183 * fore channel connection.
184 * Returns the input port (0) and sets the svc_serv bc_xprt on success
185 */
186 ret = svc_create_xprt(serv, "tcp-bc", &init_net, PF_INET, 0,
187 SVC_SOCK_ANONYMOUS);
188 if (ret < 0) {
189 rqstp = ERR_PTR(ret);
190 goto out;
191 }
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 xprt->bc_serv = serv;
198
199 INIT_LIST_HEAD(&serv->sv_cb_list);
200 spin_lock_init(&serv->sv_cb_lock);
201 init_waitqueue_head(&serv->sv_cb_waitq);
202 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
203 if (IS_ERR(rqstp)) {
204 svc_xprt_put(serv->sv_bc_xprt);
205 serv->sv_bc_xprt = NULL;
206 }
207out:
208 dprintk("--> %s return %ld\n", __func__,
209 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
210 return rqstp;
211}
212
213static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
214 struct svc_serv *serv, struct rpc_xprt *xprt,
215 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
216{
217 if (minorversion) {
218 *rqstpp = nfs41_callback_up(serv, xprt);
219 *callback_svc = nfs41_callback_svc;
220 }
221 return minorversion;
222}
223
224static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
225 struct nfs_callback_data *cb_info)
226{
227 if (minorversion)
228 xprt->bc_serv = cb_info->serv;
229}
230#else
231static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
232 struct svc_serv *serv, struct rpc_xprt *xprt,
233 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
234{
235 return 0;
236}
237
238static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
239 struct nfs_callback_data *cb_info)
240{
241}
242#endif /* CONFIG_NFS_V4_1 */
243
244/*
245 * Bring up the callback thread if it is not already up.
246 */
247int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
248{
249 struct svc_serv *serv = NULL;
250 struct svc_rqst *rqstp;
251 int (*callback_svc)(void *vrqstp);
252 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
253 char svc_name[12];
254 int ret = 0;
255 int minorversion_setup;
256 struct net *net = &init_net;
257
258 mutex_lock(&nfs_callback_mutex);
259 if (cb_info->users++ || cb_info->task != NULL) {
260 nfs_callback_bc_serv(minorversion, xprt, cb_info);
261 goto out;
262 }
263 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
264 if (!serv) {
265 ret = -ENOMEM;
266 goto out_err;
267 }
268
269 ret = svc_bind(serv, net);
270 if (ret < 0) {
271 printk(KERN_WARNING "NFS: bind callback service failed\n");
272 goto out_err;
273 }
274
275 minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion,
276 serv, xprt, &rqstp, &callback_svc);
277 if (!minorversion_setup) {
278 /* v4.0 callback setup */
279 rqstp = nfs4_callback_up(serv, xprt);
280 callback_svc = nfs4_callback_svc;
281 }
282
283 if (IS_ERR(rqstp)) {
284 ret = PTR_ERR(rqstp);
285 goto out_err;
286 }
287
288 svc_sock_update_bufs(serv);
289
290 sprintf(svc_name, "nfsv4.%u-svc", minorversion);
291 cb_info->serv = serv;
292 cb_info->rqst = rqstp;
293 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
294 if (IS_ERR(cb_info->task)) {
295 ret = PTR_ERR(cb_info->task);
296 svc_exit_thread(cb_info->rqst);
297 cb_info->rqst = NULL;
298 cb_info->task = NULL;
299 goto out_err;
300 }
301out:
302 /*
303 * svc_create creates the svc_serv with sv_nrthreads == 1, and then
304 * svc_prepare_thread increments that. So we need to call svc_destroy
305 * on both success and failure so that the refcount is 1 when the
306 * thread exits.
307 */
308 if (serv)
309 svc_destroy(serv);
310 mutex_unlock(&nfs_callback_mutex);
311 return ret;
312out_err:
313 dprintk("NFS: Couldn't create callback socket or server thread; "
314 "err = %d\n", ret);
315 cb_info->users--;
316 if (serv)
317 svc_shutdown_net(serv, net);
318 goto out;
319}
320
321/*
322 * Kill the callback thread if it's no longer being used.
323 */
324void nfs_callback_down(int minorversion)
325{
326 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
327
328 mutex_lock(&nfs_callback_mutex);
329 cb_info->users--;
330 if (cb_info->users == 0 && cb_info->task != NULL) {
331 kthread_stop(cb_info->task);
332 svc_shutdown_net(cb_info->serv, &init_net);
333 svc_exit_thread(cb_info->rqst);
334 cb_info->serv = NULL;
335 cb_info->rqst = NULL;
336 cb_info->task = NULL;
337 }
338 mutex_unlock(&nfs_callback_mutex);
339}
340
341/* Boolean check of RPC_AUTH_GSS principal */
342int
343check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
344{
345 char *p = rqstp->rq_cred.cr_principal;
346
347 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
348 return 1;
349
350 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
351 if (clp->cl_minorversion != 0)
352 return 0;
353 /*
354 * It might just be a normal user principal, in which case
355 * userspace won't bother to tell us the name at all.
356 */
357 if (p == NULL)
358 return 0;
359
360 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
361
362 if (memcmp(p, "nfs@", 4) != 0)
363 return 0;
364 p += 4;
365 if (strcmp(p, clp->cl_hostname) != 0)
366 return 0;
367 return 1;
368}
369
370/*
371 * pg_authenticate method for nfsv4 callback threads.
372 *
373 * The authflavor has been negotiated, so an incorrect flavor is a server
374 * bug. Drop packets with incorrect authflavor.
375 *
376 * All other checking done after NFS decoding where the nfs_client can be
377 * found in nfs4_callback_compound
378 */
379static int nfs_callback_authenticate(struct svc_rqst *rqstp)
380{
381 switch (rqstp->rq_authop->flavour) {
382 case RPC_AUTH_NULL:
383 if (rqstp->rq_proc != CB_NULL)
384 return SVC_DROP;
385 break;
386 case RPC_AUTH_GSS:
387 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
388 if (svc_is_backchannel(rqstp))
389 return SVC_DROP;
390 }
391 return SVC_OK;
392}
393
394/*
395 * Define NFS4 callback program
396 */
397static struct svc_version *nfs4_callback_version[] = {
398 [1] = &nfs4_callback_version1,
399 [4] = &nfs4_callback_version4,
400};
401
402static struct svc_stat nfs4_callback_stats;
403
404static struct svc_program nfs4_callback_program = {
405 .pg_prog = NFS4_CALLBACK, /* RPC service number */
406 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
407 .pg_vers = nfs4_callback_version, /* version table */
408 .pg_name = "NFSv4 callback", /* service name */
409 .pg_class = "nfs", /* authentication class */
410 .pg_stats = &nfs4_callback_stats,
411 .pg_authenticate = nfs_callback_authenticate,
412};
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/sunrpc/svc.h>
13#include <linux/sunrpc/svcsock.h>
14#include <linux/nfs_fs.h>
15#include <linux/errno.h>
16#include <linux/mutex.h>
17#include <linux/freezer.h>
18#include <linux/kthread.h>
19#include <linux/sunrpc/svcauth_gss.h>
20#include <linux/sunrpc/bc_xprt.h>
21
22#include <net/inet_sock.h>
23
24#include "nfs4_fs.h"
25#include "callback.h"
26#include "internal.h"
27#include "netns.h"
28
29#define NFSDBG_FACILITY NFSDBG_CALLBACK
30
31struct nfs_callback_data {
32 unsigned int users;
33 struct svc_serv *serv;
34 struct svc_rqst *rqst;
35 struct task_struct *task;
36};
37
38static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
39static DEFINE_MUTEX(nfs_callback_mutex);
40static struct svc_program nfs4_callback_program;
41
42static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
43{
44 int ret;
45 struct nfs_net *nn = net_generic(net, nfs_net_id);
46
47 ret = svc_create_xprt(serv, "tcp", net, PF_INET,
48 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
49 if (ret <= 0)
50 goto out_err;
51 nn->nfs_callback_tcpport = ret;
52 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
53 nn->nfs_callback_tcpport, PF_INET, net);
54
55 ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
56 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
57 if (ret > 0) {
58 nn->nfs_callback_tcpport6 = ret;
59 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
60 nn->nfs_callback_tcpport6, PF_INET6, net);
61 } else if (ret != -EAFNOSUPPORT)
62 goto out_err;
63 return 0;
64
65out_err:
66 return (ret) ? ret : -ENOMEM;
67}
68
69/*
70 * This is the NFSv4 callback kernel thread.
71 */
72static int
73nfs4_callback_svc(void *vrqstp)
74{
75 int err;
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 continue;
87 svc_process(rqstp);
88 }
89 return 0;
90}
91
92/*
93 * Prepare to bring up the NFSv4 callback service
94 */
95static struct svc_rqst *
96nfs4_callback_up(struct svc_serv *serv)
97{
98 return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
99}
100
101#if defined(CONFIG_NFS_V4_1)
102static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
103{
104 /*
105 * Create an svc_sock for the back channel service that shares the
106 * fore channel connection.
107 * Returns the input port (0) and sets the svc_serv bc_xprt on success
108 */
109 return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
110 SVC_SOCK_ANONYMOUS);
111}
112
113/*
114 * The callback service for NFSv4.1 callbacks
115 */
116static int
117nfs41_callback_svc(void *vrqstp)
118{
119 struct svc_rqst *rqstp = vrqstp;
120 struct svc_serv *serv = rqstp->rq_server;
121 struct rpc_rqst *req;
122 int error;
123 DEFINE_WAIT(wq);
124
125 set_freezable();
126
127 while (!kthread_should_stop()) {
128 if (try_to_freeze())
129 continue;
130
131 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
132 spin_lock_bh(&serv->sv_cb_lock);
133 if (!list_empty(&serv->sv_cb_list)) {
134 req = list_first_entry(&serv->sv_cb_list,
135 struct rpc_rqst, rq_bc_list);
136 list_del(&req->rq_bc_list);
137 spin_unlock_bh(&serv->sv_cb_lock);
138 dprintk("Invoking bc_svc_process()\n");
139 error = bc_svc_process(serv, req, rqstp);
140 dprintk("bc_svc_process() returned w/ error code= %d\n",
141 error);
142 } else {
143 spin_unlock_bh(&serv->sv_cb_lock);
144 schedule();
145 }
146 finish_wait(&serv->sv_cb_waitq, &wq);
147 }
148 return 0;
149}
150
151/*
152 * Bring up the NFSv4.1 callback service
153 */
154static struct svc_rqst *
155nfs41_callback_up(struct svc_serv *serv)
156{
157 struct svc_rqst *rqstp;
158
159 INIT_LIST_HEAD(&serv->sv_cb_list);
160 spin_lock_init(&serv->sv_cb_lock);
161 init_waitqueue_head(&serv->sv_cb_waitq);
162 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
163 if (IS_ERR(rqstp)) {
164 svc_xprt_put(serv->sv_bc_xprt);
165 serv->sv_bc_xprt = NULL;
166 }
167 dprintk("--> %s return %d\n", __func__, PTR_ERR_OR_ZERO(rqstp));
168 return rqstp;
169}
170
171static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
172 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
173{
174 *rqstpp = nfs41_callback_up(serv);
175 *callback_svc = nfs41_callback_svc;
176}
177
178static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
179 struct svc_serv *serv)
180{
181 if (minorversion)
182 /*
183 * Save the svc_serv in the transport so that it can
184 * be referenced when the session backchannel is initialized
185 */
186 xprt->bc_serv = serv;
187}
188#else
189static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
190{
191 return 0;
192}
193
194static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
195 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
196{
197 *rqstpp = ERR_PTR(-ENOTSUPP);
198 *callback_svc = ERR_PTR(-ENOTSUPP);
199}
200
201static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
202 struct svc_serv *serv)
203{
204}
205#endif /* CONFIG_NFS_V4_1 */
206
207static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
208 struct svc_serv *serv)
209{
210 struct svc_rqst *rqstp;
211 int (*callback_svc)(void *vrqstp);
212 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
213 int ret;
214
215 nfs_callback_bc_serv(minorversion, xprt, serv);
216
217 if (cb_info->task)
218 return 0;
219
220 switch (minorversion) {
221 case 0:
222 /* v4.0 callback setup */
223 rqstp = nfs4_callback_up(serv);
224 callback_svc = nfs4_callback_svc;
225 break;
226 default:
227 nfs_minorversion_callback_svc_setup(serv,
228 &rqstp, &callback_svc);
229 }
230
231 if (IS_ERR(rqstp))
232 return PTR_ERR(rqstp);
233
234 svc_sock_update_bufs(serv);
235
236 cb_info->serv = serv;
237 cb_info->rqst = rqstp;
238 cb_info->task = kthread_run(callback_svc, cb_info->rqst,
239 "nfsv4.%u-svc", minorversion);
240 if (IS_ERR(cb_info->task)) {
241 ret = PTR_ERR(cb_info->task);
242 svc_exit_thread(cb_info->rqst);
243 cb_info->rqst = NULL;
244 cb_info->task = NULL;
245 return ret;
246 }
247 dprintk("nfs_callback_up: service started\n");
248 return 0;
249}
250
251static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
252{
253 struct nfs_net *nn = net_generic(net, nfs_net_id);
254
255 if (--nn->cb_users[minorversion])
256 return;
257
258 dprintk("NFS: destroy per-net callback data; net=%p\n", net);
259 svc_shutdown_net(serv, net);
260}
261
262static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
263{
264 struct nfs_net *nn = net_generic(net, nfs_net_id);
265 int ret;
266
267 if (nn->cb_users[minorversion]++)
268 return 0;
269
270 dprintk("NFS: create per-net callback data; net=%p\n", net);
271
272 ret = svc_bind(serv, net);
273 if (ret < 0) {
274 printk(KERN_WARNING "NFS: bind callback service failed\n");
275 goto err_bind;
276 }
277
278 switch (minorversion) {
279 case 0:
280 ret = nfs4_callback_up_net(serv, net);
281 break;
282 case 1:
283 case 2:
284 ret = nfs41_callback_up_net(serv, net);
285 break;
286 default:
287 printk(KERN_ERR "NFS: unknown callback version: %d\n",
288 minorversion);
289 ret = -EINVAL;
290 break;
291 }
292
293 if (ret < 0) {
294 printk(KERN_ERR "NFS: callback service start failed\n");
295 goto err_socks;
296 }
297 return 0;
298
299err_socks:
300 svc_rpcb_cleanup(serv, net);
301err_bind:
302 dprintk("NFS: Couldn't create callback socket: err = %d; "
303 "net = %p\n", ret, net);
304 return ret;
305}
306
307static struct svc_serv *nfs_callback_create_svc(int minorversion)
308{
309 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
310 struct svc_serv *serv;
311
312 /*
313 * Check whether we're already up and running.
314 */
315 if (cb_info->task) {
316 /*
317 * Note: increase service usage, because later in case of error
318 * svc_destroy() will be called.
319 */
320 svc_get(cb_info->serv);
321 return cb_info->serv;
322 }
323
324 /*
325 * Sanity check: if there's no task,
326 * we should be the first user ...
327 */
328 if (cb_info->users)
329 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
330 cb_info->users);
331
332 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
333 if (!serv) {
334 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
335 return ERR_PTR(-ENOMEM);
336 }
337 /* As there is only one thread we need to over-ride the
338 * default maximum of 80 connections
339 */
340 serv->sv_maxconn = 1024;
341 dprintk("nfs_callback_create_svc: service created\n");
342 return serv;
343}
344
345/*
346 * Bring up the callback thread if it is not already up.
347 */
348int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
349{
350 struct svc_serv *serv;
351 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
352 int ret;
353 struct net *net = xprt->xprt_net;
354
355 mutex_lock(&nfs_callback_mutex);
356
357 serv = nfs_callback_create_svc(minorversion);
358 if (IS_ERR(serv)) {
359 ret = PTR_ERR(serv);
360 goto err_create;
361 }
362
363 ret = nfs_callback_up_net(minorversion, serv, net);
364 if (ret < 0)
365 goto err_net;
366
367 ret = nfs_callback_start_svc(minorversion, xprt, serv);
368 if (ret < 0)
369 goto err_start;
370
371 cb_info->users++;
372 /*
373 * svc_create creates the svc_serv with sv_nrthreads == 1, and then
374 * svc_prepare_thread increments that. So we need to call svc_destroy
375 * on both success and failure so that the refcount is 1 when the
376 * thread exits.
377 */
378err_net:
379 svc_destroy(serv);
380err_create:
381 mutex_unlock(&nfs_callback_mutex);
382 return ret;
383
384err_start:
385 nfs_callback_down_net(minorversion, serv, net);
386 dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
387 goto err_net;
388}
389
390/*
391 * Kill the callback thread if it's no longer being used.
392 */
393void nfs_callback_down(int minorversion, struct net *net)
394{
395 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
396
397 mutex_lock(&nfs_callback_mutex);
398 nfs_callback_down_net(minorversion, cb_info->serv, net);
399 cb_info->users--;
400 if (cb_info->users == 0 && cb_info->task != NULL) {
401 kthread_stop(cb_info->task);
402 dprintk("nfs_callback_down: service stopped\n");
403 svc_exit_thread(cb_info->rqst);
404 dprintk("nfs_callback_down: service destroyed\n");
405 cb_info->serv = NULL;
406 cb_info->rqst = NULL;
407 cb_info->task = NULL;
408 }
409 mutex_unlock(&nfs_callback_mutex);
410}
411
412/* Boolean check of RPC_AUTH_GSS principal */
413int
414check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
415{
416 char *p = rqstp->rq_cred.cr_principal;
417
418 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
419 return 1;
420
421 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
422 if (clp->cl_minorversion != 0)
423 return 0;
424 /*
425 * It might just be a normal user principal, in which case
426 * userspace won't bother to tell us the name at all.
427 */
428 if (p == NULL)
429 return 0;
430
431 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
432
433 if (memcmp(p, "nfs@", 4) != 0)
434 return 0;
435 p += 4;
436 if (strcmp(p, clp->cl_hostname) != 0)
437 return 0;
438 return 1;
439}
440
441/*
442 * pg_authenticate method for nfsv4 callback threads.
443 *
444 * The authflavor has been negotiated, so an incorrect flavor is a server
445 * bug. Drop packets with incorrect authflavor.
446 *
447 * All other checking done after NFS decoding where the nfs_client can be
448 * found in nfs4_callback_compound
449 */
450static int nfs_callback_authenticate(struct svc_rqst *rqstp)
451{
452 switch (rqstp->rq_authop->flavour) {
453 case RPC_AUTH_NULL:
454 if (rqstp->rq_proc != CB_NULL)
455 return SVC_DROP;
456 break;
457 case RPC_AUTH_GSS:
458 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
459 if (svc_is_backchannel(rqstp))
460 return SVC_DROP;
461 }
462 return SVC_OK;
463}
464
465/*
466 * Define NFS4 callback program
467 */
468static struct svc_version *nfs4_callback_version[] = {
469 [1] = &nfs4_callback_version1,
470 [4] = &nfs4_callback_version4,
471};
472
473static struct svc_stat nfs4_callback_stats;
474
475static struct svc_program nfs4_callback_program = {
476 .pg_prog = NFS4_CALLBACK, /* RPC service number */
477 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
478 .pg_vers = nfs4_callback_version, /* version table */
479 .pg_name = "NFSv4 callback", /* service name */
480 .pg_class = "nfs", /* authentication class */
481 .pg_stats = &nfs4_callback_stats,
482 .pg_authenticate = nfs_callback_authenticate,
483};