Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/nfs/callback.c
4 *
5 * Copyright (C) 2004 Trond Myklebust
6 *
7 * NFSv4 callback handling
8 */
9
10#include <linux/completion.h>
11#include <linux/ip.h>
12#include <linux/module.h>
13#include <linux/sched/signal.h>
14#include <linux/sunrpc/svc.h>
15#include <linux/sunrpc/svcsock.h>
16#include <linux/nfs_fs.h>
17#include <linux/errno.h>
18#include <linux/mutex.h>
19#include <linux/freezer.h>
20#include <linux/sunrpc/svcauth_gss.h>
21#include <linux/sunrpc/bc_xprt.h>
22
23#include <net/inet_sock.h>
24
25#include "nfs4_fs.h"
26#include "callback.h"
27#include "internal.h"
28#include "netns.h"
29
30#define NFSDBG_FACILITY NFSDBG_CALLBACK
31
32struct nfs_callback_data {
33 unsigned int users;
34 struct svc_serv *serv;
35};
36
37static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
38static DEFINE_MUTEX(nfs_callback_mutex);
39static struct svc_program nfs4_callback_program;
40
41static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
42{
43 const struct cred *cred = current_cred();
44 int ret;
45 struct nfs_net *nn = net_generic(net, nfs_net_id);
46
47 ret = svc_xprt_create(serv, "tcp", net, PF_INET,
48 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
49 cred);
50 if (ret <= 0)
51 goto out_err;
52 nn->nfs_callback_tcpport = ret;
53 dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
54 nn->nfs_callback_tcpport, PF_INET, net->ns.inum);
55
56 ret = svc_xprt_create(serv, "tcp", net, PF_INET6,
57 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS,
58 cred);
59 if (ret > 0) {
60 nn->nfs_callback_tcpport6 = ret;
61 dprintk("NFS: Callback listener port = %u (af %u, net %x)\n",
62 nn->nfs_callback_tcpport6, PF_INET6, net->ns.inum);
63 } else if (ret != -EAFNOSUPPORT)
64 goto out_err;
65 return 0;
66
67out_err:
68 return (ret) ? ret : -ENOMEM;
69}
70
71/*
72 * This is the NFSv4 callback kernel thread.
73 */
74static int
75nfs4_callback_svc(void *vrqstp)
76{
77 int err;
78 struct svc_rqst *rqstp = vrqstp;
79
80 set_freezable();
81
82 while (!kthread_freezable_should_stop(NULL)) {
83
84 if (signal_pending(current))
85 flush_signals(current);
86 /*
87 * Listen for a request on the socket
88 */
89 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
90 if (err == -EAGAIN || err == -EINTR)
91 continue;
92 svc_process(rqstp);
93 }
94
95 svc_exit_thread(rqstp);
96 return 0;
97}
98
99#if defined(CONFIG_NFS_V4_1)
100/*
101 * The callback service for NFSv4.1 callbacks
102 */
103static int
104nfs41_callback_svc(void *vrqstp)
105{
106 struct svc_rqst *rqstp = vrqstp;
107 struct svc_serv *serv = rqstp->rq_server;
108 struct rpc_rqst *req;
109 int error;
110 DEFINE_WAIT(wq);
111
112 set_freezable();
113
114 while (!kthread_freezable_should_stop(NULL)) {
115
116 if (signal_pending(current))
117 flush_signals(current);
118
119 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
120 spin_lock_bh(&serv->sv_cb_lock);
121 if (!list_empty(&serv->sv_cb_list)) {
122 req = list_first_entry(&serv->sv_cb_list,
123 struct rpc_rqst, rq_bc_list);
124 list_del(&req->rq_bc_list);
125 spin_unlock_bh(&serv->sv_cb_lock);
126 finish_wait(&serv->sv_cb_waitq, &wq);
127 dprintk("Invoking bc_svc_process()\n");
128 error = bc_svc_process(serv, req, rqstp);
129 dprintk("bc_svc_process() returned w/ error code= %d\n",
130 error);
131 } else {
132 spin_unlock_bh(&serv->sv_cb_lock);
133 if (!kthread_should_stop())
134 schedule();
135 finish_wait(&serv->sv_cb_waitq, &wq);
136 }
137 }
138
139 svc_exit_thread(rqstp);
140 return 0;
141}
142
143static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
144 struct svc_serv *serv)
145{
146 if (minorversion)
147 /*
148 * Save the svc_serv in the transport so that it can
149 * be referenced when the session backchannel is initialized
150 */
151 xprt->bc_serv = serv;
152}
153#else
154static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
155 struct svc_serv *serv)
156{
157}
158#endif /* CONFIG_NFS_V4_1 */
159
160static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
161 struct svc_serv *serv)
162{
163 int nrservs = nfs_callback_nr_threads;
164 int ret;
165
166 nfs_callback_bc_serv(minorversion, xprt, serv);
167
168 if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS)
169 nrservs = NFS4_MIN_NR_CALLBACK_THREADS;
170
171 if (serv->sv_nrthreads == nrservs)
172 return 0;
173
174 ret = svc_set_num_threads(serv, NULL, nrservs);
175 if (ret) {
176 svc_set_num_threads(serv, NULL, 0);
177 return ret;
178 }
179 dprintk("nfs_callback_up: service started\n");
180 return 0;
181}
182
183static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
184{
185 struct nfs_net *nn = net_generic(net, nfs_net_id);
186
187 if (--nn->cb_users[minorversion])
188 return;
189
190 dprintk("NFS: destroy per-net callback data; net=%x\n", net->ns.inum);
191 svc_xprt_destroy_all(serv, net);
192}
193
194static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
195 struct net *net, struct rpc_xprt *xprt)
196{
197 struct nfs_net *nn = net_generic(net, nfs_net_id);
198 int ret;
199
200 if (nn->cb_users[minorversion]++)
201 return 0;
202
203 dprintk("NFS: create per-net callback data; net=%x\n", net->ns.inum);
204
205 ret = svc_bind(serv, net);
206 if (ret < 0) {
207 printk(KERN_WARNING "NFS: bind callback service failed\n");
208 goto err_bind;
209 }
210
211 ret = 0;
212 if (!IS_ENABLED(CONFIG_NFS_V4_1) || minorversion == 0)
213 ret = nfs4_callback_up_net(serv, net);
214 else if (xprt->ops->bc_setup)
215 set_bc_enabled(serv);
216 else
217 ret = -EPROTONOSUPPORT;
218
219 if (ret < 0) {
220 printk(KERN_ERR "NFS: callback service start failed\n");
221 goto err_socks;
222 }
223 return 0;
224
225err_socks:
226 svc_rpcb_cleanup(serv, net);
227err_bind:
228 nn->cb_users[minorversion]--;
229 dprintk("NFS: Couldn't create callback socket: err = %d; "
230 "net = %x\n", ret, net->ns.inum);
231 return ret;
232}
233
234static struct svc_serv *nfs_callback_create_svc(int minorversion)
235{
236 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
237 int (*threadfn)(void *data);
238 struct svc_serv *serv;
239
240 /*
241 * Check whether we're already up and running.
242 */
243 if (cb_info->serv)
244 return svc_get(cb_info->serv);
245
246 /*
247 * Sanity check: if there's no task,
248 * we should be the first user ...
249 */
250 if (cb_info->users)
251 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
252 cb_info->users);
253
254 threadfn = nfs4_callback_svc;
255#if defined(CONFIG_NFS_V4_1)
256 if (minorversion)
257 threadfn = nfs41_callback_svc;
258#else
259 if (minorversion)
260 return ERR_PTR(-ENOTSUPP);
261#endif
262 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
263 threadfn);
264 if (!serv) {
265 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
266 return ERR_PTR(-ENOMEM);
267 }
268 cb_info->serv = serv;
269 /* As there is only one thread we need to over-ride the
270 * default maximum of 80 connections
271 */
272 serv->sv_maxconn = 1024;
273 dprintk("nfs_callback_create_svc: service created\n");
274 return serv;
275}
276
277/*
278 * Bring up the callback thread if it is not already up.
279 */
280int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
281{
282 struct svc_serv *serv;
283 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
284 int ret;
285 struct net *net = xprt->xprt_net;
286
287 mutex_lock(&nfs_callback_mutex);
288
289 serv = nfs_callback_create_svc(minorversion);
290 if (IS_ERR(serv)) {
291 ret = PTR_ERR(serv);
292 goto err_create;
293 }
294
295 ret = nfs_callback_up_net(minorversion, serv, net, xprt);
296 if (ret < 0)
297 goto err_net;
298
299 ret = nfs_callback_start_svc(minorversion, xprt, serv);
300 if (ret < 0)
301 goto err_start;
302
303 cb_info->users++;
304err_net:
305 if (!cb_info->users)
306 cb_info->serv = NULL;
307 svc_put(serv);
308err_create:
309 mutex_unlock(&nfs_callback_mutex);
310 return ret;
311
312err_start:
313 nfs_callback_down_net(minorversion, serv, net);
314 dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
315 goto err_net;
316}
317
318/*
319 * Kill the callback thread if it's no longer being used.
320 */
321void nfs_callback_down(int minorversion, struct net *net)
322{
323 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
324 struct svc_serv *serv;
325
326 mutex_lock(&nfs_callback_mutex);
327 serv = cb_info->serv;
328 nfs_callback_down_net(minorversion, serv, net);
329 cb_info->users--;
330 if (cb_info->users == 0) {
331 svc_get(serv);
332 svc_set_num_threads(serv, NULL, 0);
333 svc_put(serv);
334 dprintk("nfs_callback_down: service destroyed\n");
335 cb_info->serv = NULL;
336 }
337 mutex_unlock(&nfs_callback_mutex);
338}
339
340/* Boolean check of RPC_AUTH_GSS principal */
341int
342check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
343{
344 char *p = rqstp->rq_cred.cr_principal;
345
346 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
347 return 1;
348
349 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
350 if (clp->cl_minorversion != 0)
351 return 0;
352 /*
353 * It might just be a normal user principal, in which case
354 * userspace won't bother to tell us the name at all.
355 */
356 if (p == NULL)
357 return 0;
358
359 /*
360 * Did we get the acceptor from userland during the SETCLIENID
361 * negotiation?
362 */
363 if (clp->cl_acceptor)
364 return !strcmp(p, clp->cl_acceptor);
365
366 /*
367 * Otherwise try to verify it using the cl_hostname. Note that this
368 * doesn't work if a non-canonical hostname was used in the devname.
369 */
370
371 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
372
373 if (memcmp(p, "nfs@", 4) != 0)
374 return 0;
375 p += 4;
376 if (strcmp(p, clp->cl_hostname) != 0)
377 return 0;
378 return 1;
379}
380
381/*
382 * pg_authenticate method for nfsv4 callback threads.
383 *
384 * The authflavor has been negotiated, so an incorrect flavor is a server
385 * bug. Deny packets with incorrect authflavor.
386 *
387 * All other checking done after NFS decoding where the nfs_client can be
388 * found in nfs4_callback_compound
389 */
390static int nfs_callback_authenticate(struct svc_rqst *rqstp)
391{
392 rqstp->rq_auth_stat = rpc_autherr_badcred;
393
394 switch (rqstp->rq_authop->flavour) {
395 case RPC_AUTH_NULL:
396 if (rqstp->rq_proc != CB_NULL)
397 return SVC_DENIED;
398 break;
399 case RPC_AUTH_GSS:
400 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
401 if (svc_is_backchannel(rqstp))
402 return SVC_DENIED;
403 }
404
405 rqstp->rq_auth_stat = rpc_auth_ok;
406 return SVC_OK;
407}
408
409/*
410 * Define NFS4 callback program
411 */
412static const struct svc_version *nfs4_callback_version[] = {
413 [1] = &nfs4_callback_version1,
414 [4] = &nfs4_callback_version4,
415};
416
417static struct svc_stat nfs4_callback_stats;
418
419static struct svc_program nfs4_callback_program = {
420 .pg_prog = NFS4_CALLBACK, /* RPC service number */
421 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
422 .pg_vers = nfs4_callback_version, /* version table */
423 .pg_name = "NFSv4 callback", /* service name */
424 .pg_class = "nfs", /* authentication class */
425 .pg_stats = &nfs4_callback_stats,
426 .pg_authenticate = nfs_callback_authenticate,
427 .pg_init_request = svc_generic_init_request,
428 .pg_rpcbind_set = svc_generic_rpcbind_set,
429};
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};