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 31 struct nfs_callback_data { 32 unsigned int users; 33 struct svc_serv *serv; 34 struct svc_rqst *rqst; 35 struct task_struct *task; 36 }; 37 38 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1]; 39 static DEFINE_MUTEX(nfs_callback_mutex); 40 static struct svc_program nfs4_callback_program; 41 42 static 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 65 out_err: 66 return (ret) ? ret : -ENOMEM; 67 } 68 69 /* 70 * This is the NFSv4 callback kernel thread. 71 */ 72 static int 73 nfs4_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 */ 95 static struct svc_rqst * 96 nfs4_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) 102 static 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 */ 116 static int 117 nfs41_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 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 129 spin_lock_bh(&serv->sv_cb_lock); 130 if (!list_empty(&serv->sv_cb_list)) { 131 req = list_first_entry(&serv->sv_cb_list, 132 struct rpc_rqst, rq_bc_list); 133 list_del(&req->rq_bc_list); 134 spin_unlock_bh(&serv->sv_cb_lock); 135 dprintk("Invoking bc_svc_process()\n"); 136 error = bc_svc_process(serv, req, rqstp); 137 dprintk("bc_svc_process() returned w/ error code= %d\n", 138 error); 139 } else { 140 spin_unlock_bh(&serv->sv_cb_lock); 141 schedule(); 142 } 143 finish_wait(&serv->sv_cb_waitq, &wq); 144 } 145 return 0; 146 } 147 148 /* 149 * Bring up the NFSv4.1 callback service 150 */ 151 static struct svc_rqst * 152 nfs41_callback_up(struct svc_serv *serv) 153 { 154 struct svc_rqst *rqstp; 155 156 INIT_LIST_HEAD(&serv->sv_cb_list); 157 spin_lock_init(&serv->sv_cb_lock); 158 init_waitqueue_head(&serv->sv_cb_waitq); 159 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE); 160 if (IS_ERR(rqstp)) { 161 svc_xprt_put(serv->sv_bc_xprt); 162 serv->sv_bc_xprt = NULL; 163 } 164 dprintk("--> %s return %ld\n", __func__, 165 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0); 166 return rqstp; 167 } 168 169 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv, 170 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 171 { 172 *rqstpp = nfs41_callback_up(serv); 173 *callback_svc = nfs41_callback_svc; 174 } 175 176 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 177 struct svc_serv *serv) 178 { 179 if (minorversion) 180 /* 181 * Save the svc_serv in the transport so that it can 182 * be referenced when the session backchannel is initialized 183 */ 184 xprt->bc_serv = serv; 185 } 186 #else 187 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net) 188 { 189 return 0; 190 } 191 192 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv, 193 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 194 { 195 *rqstpp = ERR_PTR(-ENOTSUPP); 196 *callback_svc = ERR_PTR(-ENOTSUPP); 197 } 198 199 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 200 struct svc_serv *serv) 201 { 202 } 203 #endif /* CONFIG_NFS_V4_1 */ 204 205 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt, 206 struct svc_serv *serv) 207 { 208 struct svc_rqst *rqstp; 209 int (*callback_svc)(void *vrqstp); 210 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 211 char svc_name[12]; 212 int ret; 213 214 nfs_callback_bc_serv(minorversion, xprt, serv); 215 216 if (cb_info->task) 217 return 0; 218 219 switch (minorversion) { 220 case 0: 221 /* v4.0 callback setup */ 222 rqstp = nfs4_callback_up(serv); 223 callback_svc = nfs4_callback_svc; 224 break; 225 default: 226 nfs_minorversion_callback_svc_setup(serv, 227 &rqstp, &callback_svc); 228 } 229 230 if (IS_ERR(rqstp)) 231 return PTR_ERR(rqstp); 232 233 svc_sock_update_bufs(serv); 234 235 sprintf(svc_name, "nfsv4.%u-svc", minorversion); 236 cb_info->serv = serv; 237 cb_info->rqst = rqstp; 238 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); 239 if (IS_ERR(cb_info->task)) { 240 ret = PTR_ERR(cb_info->task); 241 svc_exit_thread(cb_info->rqst); 242 cb_info->rqst = NULL; 243 cb_info->task = NULL; 244 return ret; 245 } 246 dprintk("nfs_callback_up: service started\n"); 247 return 0; 248 } 249 250 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net) 251 { 252 struct nfs_net *nn = net_generic(net, nfs_net_id); 253 254 if (--nn->cb_users[minorversion]) 255 return; 256 257 dprintk("NFS: destroy per-net callback data; net=%p\n", net); 258 svc_shutdown_net(serv, net); 259 } 260 261 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net) 262 { 263 struct nfs_net *nn = net_generic(net, nfs_net_id); 264 int ret; 265 266 if (nn->cb_users[minorversion]++) 267 return 0; 268 269 dprintk("NFS: create per-net callback data; net=%p\n", net); 270 271 ret = svc_bind(serv, net); 272 if (ret < 0) { 273 printk(KERN_WARNING "NFS: bind callback service failed\n"); 274 goto err_bind; 275 } 276 277 switch (minorversion) { 278 case 0: 279 ret = nfs4_callback_up_net(serv, net); 280 break; 281 case 1: 282 ret = nfs41_callback_up_net(serv, net); 283 break; 284 default: 285 printk(KERN_ERR "NFS: unknown callback version: %d\n", 286 minorversion); 287 ret = -EINVAL; 288 break; 289 } 290 291 if (ret < 0) { 292 printk(KERN_ERR "NFS: callback service start failed\n"); 293 goto err_socks; 294 } 295 return 0; 296 297 err_socks: 298 svc_rpcb_cleanup(serv, net); 299 err_bind: 300 dprintk("NFS: Couldn't create callback socket: err = %d; " 301 "net = %p\n", ret, net); 302 return ret; 303 } 304 305 static struct svc_serv *nfs_callback_create_svc(int minorversion) 306 { 307 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 308 struct svc_serv *serv; 309 310 /* 311 * Check whether we're already up and running. 312 */ 313 if (cb_info->task) { 314 /* 315 * Note: increase service usage, because later in case of error 316 * svc_destroy() will be called. 317 */ 318 svc_get(cb_info->serv); 319 return cb_info->serv; 320 } 321 322 /* 323 * Sanity check: if there's no task, 324 * we should be the first user ... 325 */ 326 if (cb_info->users) 327 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n", 328 cb_info->users); 329 330 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 331 if (!serv) { 332 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n"); 333 return ERR_PTR(-ENOMEM); 334 } 335 /* As there is only one thread we need to over-ride the 336 * default maximum of 80 connections 337 */ 338 serv->sv_maxconn = 1024; 339 dprintk("nfs_callback_create_svc: service created\n"); 340 return serv; 341 } 342 343 /* 344 * Bring up the callback thread if it is not already up. 345 */ 346 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 347 { 348 struct svc_serv *serv; 349 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 350 int ret; 351 struct net *net = xprt->xprt_net; 352 353 mutex_lock(&nfs_callback_mutex); 354 355 serv = nfs_callback_create_svc(minorversion); 356 if (IS_ERR(serv)) { 357 ret = PTR_ERR(serv); 358 goto err_create; 359 } 360 361 ret = nfs_callback_up_net(minorversion, serv, net); 362 if (ret < 0) 363 goto err_net; 364 365 ret = nfs_callback_start_svc(minorversion, xprt, serv); 366 if (ret < 0) 367 goto err_start; 368 369 cb_info->users++; 370 /* 371 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 372 * svc_prepare_thread increments that. So we need to call svc_destroy 373 * on both success and failure so that the refcount is 1 when the 374 * thread exits. 375 */ 376 err_net: 377 svc_destroy(serv); 378 err_create: 379 mutex_unlock(&nfs_callback_mutex); 380 return ret; 381 382 err_start: 383 nfs_callback_down_net(minorversion, serv, net); 384 dprintk("NFS: Couldn't create server thread; err = %d\n", ret); 385 goto err_net; 386 } 387 388 /* 389 * Kill the callback thread if it's no longer being used. 390 */ 391 void nfs_callback_down(int minorversion, struct net *net) 392 { 393 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 394 395 mutex_lock(&nfs_callback_mutex); 396 nfs_callback_down_net(minorversion, cb_info->serv, net); 397 cb_info->users--; 398 if (cb_info->users == 0 && cb_info->task != NULL) { 399 kthread_stop(cb_info->task); 400 dprintk("nfs_callback_down: service stopped\n"); 401 svc_exit_thread(cb_info->rqst); 402 dprintk("nfs_callback_down: service destroyed\n"); 403 cb_info->serv = NULL; 404 cb_info->rqst = NULL; 405 cb_info->task = NULL; 406 } 407 mutex_unlock(&nfs_callback_mutex); 408 } 409 410 /* Boolean check of RPC_AUTH_GSS principal */ 411 int 412 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp) 413 { 414 char *p = rqstp->rq_cred.cr_principal; 415 416 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS) 417 return 1; 418 419 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */ 420 if (clp->cl_minorversion != 0) 421 return 0; 422 /* 423 * It might just be a normal user principal, in which case 424 * userspace won't bother to tell us the name at all. 425 */ 426 if (p == NULL) 427 return 0; 428 429 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 430 431 if (memcmp(p, "nfs@", 4) != 0) 432 return 0; 433 p += 4; 434 if (strcmp(p, clp->cl_hostname) != 0) 435 return 0; 436 return 1; 437 } 438 439 /* 440 * pg_authenticate method for nfsv4 callback threads. 441 * 442 * The authflavor has been negotiated, so an incorrect flavor is a server 443 * bug. Drop packets with incorrect authflavor. 444 * 445 * All other checking done after NFS decoding where the nfs_client can be 446 * found in nfs4_callback_compound 447 */ 448 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 449 { 450 switch (rqstp->rq_authop->flavour) { 451 case RPC_AUTH_NULL: 452 if (rqstp->rq_proc != CB_NULL) 453 return SVC_DROP; 454 break; 455 case RPC_AUTH_GSS: 456 /* No RPC_AUTH_GSS support yet in NFSv4.1 */ 457 if (svc_is_backchannel(rqstp)) 458 return SVC_DROP; 459 } 460 return SVC_OK; 461 } 462 463 /* 464 * Define NFS4 callback program 465 */ 466 static struct svc_version *nfs4_callback_version[] = { 467 [1] = &nfs4_callback_version1, 468 [4] = &nfs4_callback_version4, 469 }; 470 471 static struct svc_stat nfs4_callback_stats; 472 473 static struct svc_program nfs4_callback_program = { 474 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 475 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 476 .pg_vers = nfs4_callback_version, /* version table */ 477 .pg_name = "NFSv4 callback", /* service name */ 478 .pg_class = "nfs", /* authentication class */ 479 .pg_stats = &nfs4_callback_stats, 480 .pg_authenticate = nfs_callback_authenticate, 481 }; 482