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 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 */ 154 static struct svc_rqst * 155 nfs41_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 } 170 171 static 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 } 177 178 static 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 189 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net) 190 { 191 return 0; 192 } 193 194 static 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 } 200 201 static 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 */ 206 207 static 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_create(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 rqstp->rq_task = cb_info->task; 248 wake_up_process(cb_info->task); 249 dprintk("nfs_callback_up: service started\n"); 250 return 0; 251 } 252 253 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net) 254 { 255 struct nfs_net *nn = net_generic(net, nfs_net_id); 256 257 if (--nn->cb_users[minorversion]) 258 return; 259 260 dprintk("NFS: destroy per-net callback data; net=%p\n", net); 261 svc_shutdown_net(serv, net); 262 } 263 264 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net) 265 { 266 struct nfs_net *nn = net_generic(net, nfs_net_id); 267 int ret; 268 269 if (nn->cb_users[minorversion]++) 270 return 0; 271 272 dprintk("NFS: create per-net callback data; net=%p\n", net); 273 274 ret = svc_bind(serv, net); 275 if (ret < 0) { 276 printk(KERN_WARNING "NFS: bind callback service failed\n"); 277 goto err_bind; 278 } 279 280 switch (minorversion) { 281 case 0: 282 ret = nfs4_callback_up_net(serv, net); 283 break; 284 case 1: 285 case 2: 286 ret = nfs41_callback_up_net(serv, net); 287 break; 288 default: 289 printk(KERN_ERR "NFS: unknown callback version: %d\n", 290 minorversion); 291 ret = -EINVAL; 292 break; 293 } 294 295 if (ret < 0) { 296 printk(KERN_ERR "NFS: callback service start failed\n"); 297 goto err_socks; 298 } 299 return 0; 300 301 err_socks: 302 svc_rpcb_cleanup(serv, net); 303 err_bind: 304 dprintk("NFS: Couldn't create callback socket: err = %d; " 305 "net = %p\n", ret, net); 306 return ret; 307 } 308 309 static struct svc_serv *nfs_callback_create_svc(int minorversion) 310 { 311 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 312 struct svc_serv *serv; 313 314 /* 315 * Check whether we're already up and running. 316 */ 317 if (cb_info->task) { 318 /* 319 * Note: increase service usage, because later in case of error 320 * svc_destroy() will be called. 321 */ 322 svc_get(cb_info->serv); 323 return cb_info->serv; 324 } 325 326 /* 327 * Sanity check: if there's no task, 328 * we should be the first user ... 329 */ 330 if (cb_info->users) 331 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n", 332 cb_info->users); 333 334 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 335 if (!serv) { 336 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n"); 337 return ERR_PTR(-ENOMEM); 338 } 339 /* As there is only one thread we need to over-ride the 340 * default maximum of 80 connections 341 */ 342 serv->sv_maxconn = 1024; 343 dprintk("nfs_callback_create_svc: service created\n"); 344 return serv; 345 } 346 347 /* 348 * Bring up the callback thread if it is not already up. 349 */ 350 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 351 { 352 struct svc_serv *serv; 353 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 354 int ret; 355 struct net *net = xprt->xprt_net; 356 357 mutex_lock(&nfs_callback_mutex); 358 359 serv = nfs_callback_create_svc(minorversion); 360 if (IS_ERR(serv)) { 361 ret = PTR_ERR(serv); 362 goto err_create; 363 } 364 365 ret = nfs_callback_up_net(minorversion, serv, net); 366 if (ret < 0) 367 goto err_net; 368 369 ret = nfs_callback_start_svc(minorversion, xprt, serv); 370 if (ret < 0) 371 goto err_start; 372 373 cb_info->users++; 374 /* 375 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 376 * svc_prepare_thread increments that. So we need to call svc_destroy 377 * on both success and failure so that the refcount is 1 when the 378 * thread exits. 379 */ 380 err_net: 381 svc_destroy(serv); 382 err_create: 383 mutex_unlock(&nfs_callback_mutex); 384 return ret; 385 386 err_start: 387 nfs_callback_down_net(minorversion, serv, net); 388 dprintk("NFS: Couldn't create server thread; err = %d\n", ret); 389 goto err_net; 390 } 391 392 /* 393 * Kill the callback thread if it's no longer being used. 394 */ 395 void nfs_callback_down(int minorversion, struct net *net) 396 { 397 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 398 399 mutex_lock(&nfs_callback_mutex); 400 nfs_callback_down_net(minorversion, cb_info->serv, net); 401 cb_info->users--; 402 if (cb_info->users == 0 && cb_info->task != NULL) { 403 kthread_stop(cb_info->task); 404 dprintk("nfs_callback_down: service stopped\n"); 405 svc_exit_thread(cb_info->rqst); 406 dprintk("nfs_callback_down: service destroyed\n"); 407 cb_info->serv = NULL; 408 cb_info->rqst = NULL; 409 cb_info->task = NULL; 410 } 411 mutex_unlock(&nfs_callback_mutex); 412 } 413 414 /* Boolean check of RPC_AUTH_GSS principal */ 415 int 416 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp) 417 { 418 char *p = rqstp->rq_cred.cr_principal; 419 420 if (rqstp->rq_authop->flavour != RPC_AUTH_GSS) 421 return 1; 422 423 /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */ 424 if (clp->cl_minorversion != 0) 425 return 0; 426 /* 427 * It might just be a normal user principal, in which case 428 * userspace won't bother to tell us the name at all. 429 */ 430 if (p == NULL) 431 return 0; 432 433 /* 434 * Did we get the acceptor from userland during the SETCLIENID 435 * negotiation? 436 */ 437 if (clp->cl_acceptor) 438 return !strcmp(p, clp->cl_acceptor); 439 440 /* 441 * Otherwise try to verify it using the cl_hostname. Note that this 442 * doesn't work if a non-canonical hostname was used in the devname. 443 */ 444 445 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 446 447 if (memcmp(p, "nfs@", 4) != 0) 448 return 0; 449 p += 4; 450 if (strcmp(p, clp->cl_hostname) != 0) 451 return 0; 452 return 1; 453 } 454 455 /* 456 * pg_authenticate method for nfsv4 callback threads. 457 * 458 * The authflavor has been negotiated, so an incorrect flavor is a server 459 * bug. Drop packets with incorrect authflavor. 460 * 461 * All other checking done after NFS decoding where the nfs_client can be 462 * found in nfs4_callback_compound 463 */ 464 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 465 { 466 switch (rqstp->rq_authop->flavour) { 467 case RPC_AUTH_NULL: 468 if (rqstp->rq_proc != CB_NULL) 469 return SVC_DROP; 470 break; 471 case RPC_AUTH_GSS: 472 /* No RPC_AUTH_GSS support yet in NFSv4.1 */ 473 if (svc_is_backchannel(rqstp)) 474 return SVC_DROP; 475 } 476 return SVC_OK; 477 } 478 479 /* 480 * Define NFS4 callback program 481 */ 482 static struct svc_version *nfs4_callback_version[] = { 483 [1] = &nfs4_callback_version1, 484 [4] = &nfs4_callback_version4, 485 }; 486 487 static struct svc_stat nfs4_callback_stats; 488 489 static struct svc_program nfs4_callback_program = { 490 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 491 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 492 .pg_vers = nfs4_callback_version, /* version table */ 493 .pg_name = "NFSv4 callback", /* service name */ 494 .pg_class = "nfs", /* authentication class */ 495 .pg_stats = &nfs4_callback_stats, 496 .pg_authenticate = nfs_callback_authenticate, 497 }; 498