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/smp_lock.h> 13 #include <linux/sunrpc/svc.h> 14 #include <linux/sunrpc/svcsock.h> 15 #include <linux/nfs_fs.h> 16 #include <linux/mutex.h> 17 #include <linux/freezer.h> 18 #include <linux/kthread.h> 19 #include <linux/sunrpc/svcauth_gss.h> 20 #if defined(CONFIG_NFS_V4_1) 21 #include <linux/sunrpc/bc_xprt.h> 22 #endif 23 24 #include <net/inet_sock.h> 25 26 #include "nfs4_fs.h" 27 #include "callback.h" 28 #include "internal.h" 29 30 #define NFSDBG_FACILITY NFSDBG_CALLBACK 31 32 struct nfs_callback_data { 33 unsigned int users; 34 struct svc_serv *serv; 35 struct svc_rqst *rqst; 36 struct task_struct *task; 37 }; 38 39 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1]; 40 static DEFINE_MUTEX(nfs_callback_mutex); 41 static struct svc_program nfs4_callback_program; 42 43 unsigned int nfs_callback_set_tcpport; 44 unsigned short nfs_callback_tcpport; 45 unsigned short nfs_callback_tcpport6; 46 #define NFS_CALLBACK_MAXPORTNR (65535U) 47 48 static int param_set_portnr(const char *val, struct kernel_param *kp) 49 { 50 unsigned long num; 51 int ret; 52 53 if (!val) 54 return -EINVAL; 55 ret = strict_strtoul(val, 0, &num); 56 if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR) 57 return -EINVAL; 58 *((unsigned int *)kp->arg) = num; 59 return 0; 60 } 61 62 static int param_get_portnr(char *buffer, struct kernel_param *kp) 63 { 64 return param_get_uint(buffer, kp); 65 } 66 #define param_check_portnr(name, p) __param_check(name, p, unsigned int); 67 68 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644); 69 70 /* 71 * This is the NFSv4 callback kernel thread. 72 */ 73 static int 74 nfs4_callback_svc(void *vrqstp) 75 { 76 int err, preverr = 0; 77 struct svc_rqst *rqstp = vrqstp; 78 79 set_freezable(); 80 81 /* 82 * FIXME: do we really need to run this under the BKL? If so, please 83 * add a comment about what it's intended to protect. 84 */ 85 lock_kernel(); 86 while (!kthread_should_stop()) { 87 /* 88 * Listen for a request on the socket 89 */ 90 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); 91 if (err == -EAGAIN || err == -EINTR) { 92 preverr = err; 93 continue; 94 } 95 if (err < 0) { 96 if (err != preverr) { 97 printk(KERN_WARNING "%s: unexpected error " 98 "from svc_recv (%d)\n", __func__, err); 99 preverr = err; 100 } 101 schedule_timeout_uninterruptible(HZ); 102 continue; 103 } 104 preverr = err; 105 svc_process(rqstp); 106 } 107 unlock_kernel(); 108 return 0; 109 } 110 111 /* 112 * Prepare to bring up the NFSv4 callback service 113 */ 114 struct svc_rqst * 115 nfs4_callback_up(struct svc_serv *serv) 116 { 117 int ret; 118 119 ret = svc_create_xprt(serv, "tcp", PF_INET, 120 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 121 if (ret <= 0) 122 goto out_err; 123 nfs_callback_tcpport = ret; 124 dprintk("NFS: Callback listener port = %u (af %u)\n", 125 nfs_callback_tcpport, PF_INET); 126 127 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 128 ret = svc_create_xprt(serv, "tcp", PF_INET6, 129 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 130 if (ret > 0) { 131 nfs_callback_tcpport6 = ret; 132 dprintk("NFS: Callback listener port = %u (af %u)\n", 133 nfs_callback_tcpport6, PF_INET6); 134 } else if (ret == -EAFNOSUPPORT) 135 ret = 0; 136 else 137 goto out_err; 138 #endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */ 139 140 return svc_prepare_thread(serv, &serv->sv_pools[0]); 141 142 out_err: 143 if (ret == 0) 144 ret = -ENOMEM; 145 return ERR_PTR(ret); 146 } 147 148 #if defined(CONFIG_NFS_V4_1) 149 /* 150 * The callback service for NFSv4.1 callbacks 151 */ 152 static int 153 nfs41_callback_svc(void *vrqstp) 154 { 155 struct svc_rqst *rqstp = vrqstp; 156 struct svc_serv *serv = rqstp->rq_server; 157 struct rpc_rqst *req; 158 int error; 159 DEFINE_WAIT(wq); 160 161 set_freezable(); 162 163 /* 164 * FIXME: do we really need to run this under the BKL? If so, please 165 * add a comment about what it's intended to protect. 166 */ 167 lock_kernel(); 168 while (!kthread_should_stop()) { 169 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 170 spin_lock_bh(&serv->sv_cb_lock); 171 if (!list_empty(&serv->sv_cb_list)) { 172 req = list_first_entry(&serv->sv_cb_list, 173 struct rpc_rqst, rq_bc_list); 174 list_del(&req->rq_bc_list); 175 spin_unlock_bh(&serv->sv_cb_lock); 176 dprintk("Invoking bc_svc_process()\n"); 177 error = bc_svc_process(serv, req, rqstp); 178 dprintk("bc_svc_process() returned w/ error code= %d\n", 179 error); 180 } else { 181 spin_unlock_bh(&serv->sv_cb_lock); 182 schedule(); 183 } 184 finish_wait(&serv->sv_cb_waitq, &wq); 185 } 186 unlock_kernel(); 187 return 0; 188 } 189 190 /* 191 * Bring up the NFSv4.1 callback service 192 */ 193 struct svc_rqst * 194 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) 195 { 196 struct svc_xprt *bc_xprt; 197 struct svc_rqst *rqstp = ERR_PTR(-ENOMEM); 198 199 dprintk("--> %s\n", __func__); 200 /* Create a svc_sock for the service */ 201 bc_xprt = svc_sock_create(serv, xprt->prot); 202 if (!bc_xprt) 203 goto out; 204 205 /* 206 * Save the svc_serv in the transport so that it can 207 * be referenced when the session backchannel is initialized 208 */ 209 serv->bc_xprt = bc_xprt; 210 xprt->bc_serv = serv; 211 212 INIT_LIST_HEAD(&serv->sv_cb_list); 213 spin_lock_init(&serv->sv_cb_lock); 214 init_waitqueue_head(&serv->sv_cb_waitq); 215 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]); 216 if (IS_ERR(rqstp)) 217 svc_sock_destroy(bc_xprt); 218 out: 219 dprintk("--> %s return %p\n", __func__, rqstp); 220 return rqstp; 221 } 222 223 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 224 struct svc_serv *serv, struct rpc_xprt *xprt, 225 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 226 { 227 if (minorversion) { 228 *rqstpp = nfs41_callback_up(serv, xprt); 229 *callback_svc = nfs41_callback_svc; 230 } 231 return minorversion; 232 } 233 234 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 235 struct nfs_callback_data *cb_info) 236 { 237 if (minorversion) 238 xprt->bc_serv = cb_info->serv; 239 } 240 #else 241 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 242 struct svc_serv *serv, struct rpc_xprt *xprt, 243 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 244 { 245 return 0; 246 } 247 248 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 249 struct nfs_callback_data *cb_info) 250 { 251 } 252 #endif /* CONFIG_NFS_V4_1 */ 253 254 /* 255 * Bring up the callback thread if it is not already up. 256 */ 257 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 258 { 259 struct svc_serv *serv = NULL; 260 struct svc_rqst *rqstp; 261 int (*callback_svc)(void *vrqstp); 262 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 263 char svc_name[12]; 264 int ret = 0; 265 int minorversion_setup; 266 267 mutex_lock(&nfs_callback_mutex); 268 if (cb_info->users++ || cb_info->task != NULL) { 269 nfs_callback_bc_serv(minorversion, xprt, cb_info); 270 goto out; 271 } 272 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 273 if (!serv) { 274 ret = -ENOMEM; 275 goto out_err; 276 } 277 278 minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion, 279 serv, xprt, &rqstp, &callback_svc); 280 if (!minorversion_setup) { 281 /* v4.0 callback setup */ 282 rqstp = nfs4_callback_up(serv); 283 callback_svc = nfs4_callback_svc; 284 } 285 286 if (IS_ERR(rqstp)) { 287 ret = PTR_ERR(rqstp); 288 goto out_err; 289 } 290 291 svc_sock_update_bufs(serv); 292 293 sprintf(svc_name, "nfsv4.%u-svc", minorversion); 294 cb_info->serv = serv; 295 cb_info->rqst = rqstp; 296 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); 297 if (IS_ERR(cb_info->task)) { 298 ret = PTR_ERR(cb_info->task); 299 svc_exit_thread(cb_info->rqst); 300 cb_info->rqst = NULL; 301 cb_info->task = NULL; 302 goto out_err; 303 } 304 out: 305 /* 306 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 307 * svc_prepare_thread increments that. So we need to call svc_destroy 308 * on both success and failure so that the refcount is 1 when the 309 * thread exits. 310 */ 311 if (serv) 312 svc_destroy(serv); 313 mutex_unlock(&nfs_callback_mutex); 314 return ret; 315 out_err: 316 dprintk("NFS: Couldn't create callback socket or server thread; " 317 "err = %d\n", ret); 318 cb_info->users--; 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_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 static int check_gss_callback_principal(struct nfs_client *clp, 342 struct svc_rqst *rqstp) 343 { 344 struct rpc_clnt *r = clp->cl_rpcclient; 345 char *p = svc_gss_principal(rqstp); 346 347 /* 348 * It might just be a normal user principal, in which case 349 * userspace won't bother to tell us the name at all. 350 */ 351 if (p == NULL) 352 return SVC_DENIED; 353 354 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 355 356 if (memcmp(p, "nfs@", 4) != 0) 357 return SVC_DENIED; 358 p += 4; 359 if (strcmp(p, r->cl_server) != 0) 360 return SVC_DENIED; 361 return SVC_OK; 362 } 363 364 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 365 { 366 struct nfs_client *clp; 367 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 368 int ret = SVC_OK; 369 370 /* Don't talk to strangers */ 371 clp = nfs_find_client(svc_addr(rqstp), 4); 372 if (clp == NULL) 373 return SVC_DROP; 374 375 dprintk("%s: %s NFSv4 callback!\n", __func__, 376 svc_print_addr(rqstp, buf, sizeof(buf))); 377 378 switch (rqstp->rq_authop->flavour) { 379 case RPC_AUTH_NULL: 380 if (rqstp->rq_proc != CB_NULL) 381 ret = SVC_DENIED; 382 break; 383 case RPC_AUTH_UNIX: 384 break; 385 case RPC_AUTH_GSS: 386 ret = check_gss_callback_principal(clp, rqstp); 387 break; 388 default: 389 ret = SVC_DENIED; 390 } 391 nfs_put_client(clp); 392 return ret; 393 } 394 395 /* 396 * Define NFS4 callback program 397 */ 398 static struct svc_version *nfs4_callback_version[] = { 399 [1] = &nfs4_callback_version1, 400 }; 401 402 static struct svc_stat nfs4_callback_stats; 403 404 static 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 }; 413