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 #include <linux/nsproxy.h> 21 22 #include <net/inet_sock.h> 23 24 #include "nfs4_fs.h" 25 #include "callback.h" 26 #include "internal.h" 27 28 #define NFSDBG_FACILITY NFSDBG_CALLBACK 29 30 struct nfs_callback_data { 31 unsigned int users; 32 struct svc_serv *serv; 33 struct svc_rqst *rqst; 34 struct task_struct *task; 35 }; 36 37 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1]; 38 static DEFINE_MUTEX(nfs_callback_mutex); 39 static struct svc_program nfs4_callback_program; 40 41 unsigned int nfs_callback_set_tcpport; 42 unsigned short nfs_callback_tcpport; 43 unsigned short nfs_callback_tcpport6; 44 #define NFS_CALLBACK_MAXPORTNR (65535U) 45 46 static int param_set_portnr(const char *val, const struct kernel_param *kp) 47 { 48 unsigned long num; 49 int ret; 50 51 if (!val) 52 return -EINVAL; 53 ret = strict_strtoul(val, 0, &num); 54 if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR) 55 return -EINVAL; 56 *((unsigned int *)kp->arg) = num; 57 return 0; 58 } 59 static struct kernel_param_ops param_ops_portnr = { 60 .set = param_set_portnr, 61 .get = param_get_uint, 62 }; 63 #define param_check_portnr(name, p) __param_check(name, p, unsigned int); 64 65 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644); 66 67 /* 68 * This is the NFSv4 callback kernel thread. 69 */ 70 static int 71 nfs4_callback_svc(void *vrqstp) 72 { 73 int err, preverr = 0; 74 struct svc_rqst *rqstp = vrqstp; 75 76 set_freezable(); 77 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 "NFS: %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 return 0; 100 } 101 102 /* 103 * Prepare to bring up the NFSv4 callback service 104 */ 105 static struct svc_rqst * 106 nfs4_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) 107 { 108 int ret; 109 110 ret = svc_create_xprt(serv, "tcp", xprt->xprt_net, PF_INET, 111 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 112 if (ret <= 0) 113 goto out_err; 114 nfs_callback_tcpport = ret; 115 dprintk("NFS: Callback listener port = %u (af %u)\n", 116 nfs_callback_tcpport, PF_INET); 117 118 ret = svc_create_xprt(serv, "tcp", xprt->xprt_net, PF_INET6, 119 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 120 if (ret > 0) { 121 nfs_callback_tcpport6 = ret; 122 dprintk("NFS: Callback listener port = %u (af %u)\n", 123 nfs_callback_tcpport6, PF_INET6); 124 } else if (ret == -EAFNOSUPPORT) 125 ret = 0; 126 else 127 goto out_err; 128 129 return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE); 130 131 out_err: 132 if (ret == 0) 133 ret = -ENOMEM; 134 return ERR_PTR(ret); 135 } 136 137 #if defined(CONFIG_NFS_V4_1) 138 /* 139 * The callback service for NFSv4.1 callbacks 140 */ 141 static int 142 nfs41_callback_svc(void *vrqstp) 143 { 144 struct svc_rqst *rqstp = vrqstp; 145 struct svc_serv *serv = rqstp->rq_server; 146 struct rpc_rqst *req; 147 int error; 148 DEFINE_WAIT(wq); 149 150 set_freezable(); 151 152 while (!kthread_should_stop()) { 153 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 154 spin_lock_bh(&serv->sv_cb_lock); 155 if (!list_empty(&serv->sv_cb_list)) { 156 req = list_first_entry(&serv->sv_cb_list, 157 struct rpc_rqst, rq_bc_list); 158 list_del(&req->rq_bc_list); 159 spin_unlock_bh(&serv->sv_cb_lock); 160 dprintk("Invoking bc_svc_process()\n"); 161 error = bc_svc_process(serv, req, rqstp); 162 dprintk("bc_svc_process() returned w/ error code= %d\n", 163 error); 164 } else { 165 spin_unlock_bh(&serv->sv_cb_lock); 166 schedule(); 167 } 168 finish_wait(&serv->sv_cb_waitq, &wq); 169 } 170 return 0; 171 } 172 173 /* 174 * Bring up the NFSv4.1 callback service 175 */ 176 static struct svc_rqst * 177 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) 178 { 179 struct svc_rqst *rqstp; 180 int ret; 181 182 /* 183 * Create an svc_sock for the back channel service that shares the 184 * fore channel connection. 185 * Returns the input port (0) and sets the svc_serv bc_xprt on success 186 */ 187 ret = svc_create_xprt(serv, "tcp-bc", xprt->xprt_net, PF_INET, 0, 188 SVC_SOCK_ANONYMOUS); 189 if (ret < 0) { 190 rqstp = ERR_PTR(ret); 191 goto out; 192 } 193 194 /* 195 * Save the svc_serv in the transport so that it can 196 * be referenced when the session backchannel is initialized 197 */ 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], NUMA_NO_NODE); 204 if (IS_ERR(rqstp)) { 205 svc_xprt_put(serv->sv_bc_xprt); 206 serv->sv_bc_xprt = NULL; 207 } 208 out: 209 dprintk("--> %s return %ld\n", __func__, 210 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0); 211 return rqstp; 212 } 213 214 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 215 struct svc_serv *serv, struct rpc_xprt *xprt, 216 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 217 { 218 if (minorversion) { 219 *rqstpp = nfs41_callback_up(serv, xprt); 220 *callback_svc = nfs41_callback_svc; 221 } 222 return minorversion; 223 } 224 225 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 226 struct nfs_callback_data *cb_info) 227 { 228 if (minorversion) 229 xprt->bc_serv = cb_info->serv; 230 } 231 #else 232 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 233 struct svc_serv *serv, struct rpc_xprt *xprt, 234 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 235 { 236 return 0; 237 } 238 239 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 240 struct nfs_callback_data *cb_info) 241 { 242 } 243 #endif /* CONFIG_NFS_V4_1 */ 244 245 /* 246 * Bring up the callback thread if it is not already up. 247 */ 248 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 249 { 250 struct svc_serv *serv = NULL; 251 struct svc_rqst *rqstp; 252 int (*callback_svc)(void *vrqstp); 253 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 254 char svc_name[12]; 255 int ret = 0; 256 int minorversion_setup; 257 struct net *net = current->nsproxy->net_ns; 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 ret = svc_bind(serv, net); 271 if (ret < 0) { 272 printk(KERN_WARNING "NFS: bind callback service failed\n"); 273 goto out_err; 274 } 275 276 minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion, 277 serv, xprt, &rqstp, &callback_svc); 278 if (!minorversion_setup) { 279 /* v4.0 callback setup */ 280 rqstp = nfs4_callback_up(serv, xprt); 281 callback_svc = nfs4_callback_svc; 282 } 283 284 if (IS_ERR(rqstp)) { 285 ret = PTR_ERR(rqstp); 286 goto out_err; 287 } 288 289 svc_sock_update_bufs(serv); 290 291 sprintf(svc_name, "nfsv4.%u-svc", minorversion); 292 cb_info->serv = serv; 293 cb_info->rqst = rqstp; 294 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); 295 if (IS_ERR(cb_info->task)) { 296 ret = PTR_ERR(cb_info->task); 297 svc_exit_thread(cb_info->rqst); 298 cb_info->rqst = NULL; 299 cb_info->task = NULL; 300 goto out_err; 301 } 302 out: 303 /* 304 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 305 * svc_prepare_thread increments that. So we need to call svc_destroy 306 * on both success and failure so that the refcount is 1 when the 307 * thread exits. 308 */ 309 if (serv) 310 svc_destroy(serv); 311 mutex_unlock(&nfs_callback_mutex); 312 return ret; 313 out_err: 314 dprintk("NFS: Couldn't create callback socket or server thread; " 315 "err = %d\n", ret); 316 cb_info->users--; 317 if (serv) 318 svc_shutdown_net(serv, net); 319 goto out; 320 } 321 322 /* 323 * Kill the callback thread if it's no longer being used. 324 */ 325 void nfs_callback_down(int minorversion) 326 { 327 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 328 329 mutex_lock(&nfs_callback_mutex); 330 cb_info->users--; 331 if (cb_info->users == 0 && cb_info->task != NULL) { 332 kthread_stop(cb_info->task); 333 svc_shutdown_net(cb_info->serv, current->nsproxy->net_ns); 334 svc_exit_thread(cb_info->rqst); 335 cb_info->serv = NULL; 336 cb_info->rqst = NULL; 337 cb_info->task = NULL; 338 } 339 mutex_unlock(&nfs_callback_mutex); 340 } 341 342 /* Boolean check of RPC_AUTH_GSS principal */ 343 int 344 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp) 345 { 346 char *p = rqstp->rq_cred.cr_principal; 347 348 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS) 349 return 1; 350 351 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */ 352 if (clp->cl_minorversion != 0) 353 return 0; 354 /* 355 * It might just be a normal user principal, in which case 356 * userspace won't bother to tell us the name at all. 357 */ 358 if (p == NULL) 359 return 0; 360 361 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 362 363 if (memcmp(p, "nfs@", 4) != 0) 364 return 0; 365 p += 4; 366 if (strcmp(p, clp->cl_hostname) != 0) 367 return 0; 368 return 1; 369 } 370 371 /* 372 * pg_authenticate method for nfsv4 callback threads. 373 * 374 * The authflavor has been negotiated, so an incorrect flavor is a server 375 * bug. Drop packets with incorrect authflavor. 376 * 377 * All other checking done after NFS decoding where the nfs_client can be 378 * found in nfs4_callback_compound 379 */ 380 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 381 { 382 switch (rqstp->rq_authop->flavour) { 383 case RPC_AUTH_NULL: 384 if (rqstp->rq_proc != CB_NULL) 385 return SVC_DROP; 386 break; 387 case RPC_AUTH_GSS: 388 /* No RPC_AUTH_GSS support yet in NFSv4.1 */ 389 if (svc_is_backchannel(rqstp)) 390 return SVC_DROP; 391 } 392 return SVC_OK; 393 } 394 395 /* 396 * Define NFS4 callback program 397 */ 398 static struct svc_version *nfs4_callback_version[] = { 399 [1] = &nfs4_callback_version1, 400 [4] = &nfs4_callback_version4, 401 }; 402 403 static struct svc_stat nfs4_callback_stats; 404 405 static struct svc_program nfs4_callback_program = { 406 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 407 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 408 .pg_vers = nfs4_callback_version, /* version table */ 409 .pg_name = "NFSv4 callback", /* service name */ 410 .pg_class = "nfs", /* authentication class */ 411 .pg_stats = &nfs4_callback_stats, 412 .pg_authenticate = nfs_callback_authenticate, 413 }; 414