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 while (!kthread_should_stop()) { 82 /* 83 * Listen for a request on the socket 84 */ 85 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); 86 if (err == -EAGAIN || err == -EINTR) { 87 preverr = err; 88 continue; 89 } 90 if (err < 0) { 91 if (err != preverr) { 92 printk(KERN_WARNING "%s: unexpected error " 93 "from svc_recv (%d)\n", __func__, err); 94 preverr = err; 95 } 96 schedule_timeout_uninterruptible(HZ); 97 continue; 98 } 99 preverr = err; 100 svc_process(rqstp); 101 } 102 return 0; 103 } 104 105 /* 106 * Prepare to bring up the NFSv4 callback service 107 */ 108 struct svc_rqst * 109 nfs4_callback_up(struct svc_serv *serv) 110 { 111 int ret; 112 113 ret = svc_create_xprt(serv, "tcp", PF_INET, 114 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 115 if (ret <= 0) 116 goto out_err; 117 nfs_callback_tcpport = ret; 118 dprintk("NFS: Callback listener port = %u (af %u)\n", 119 nfs_callback_tcpport, PF_INET); 120 121 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 122 ret = svc_create_xprt(serv, "tcp", PF_INET6, 123 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 124 if (ret > 0) { 125 nfs_callback_tcpport6 = ret; 126 dprintk("NFS: Callback listener port = %u (af %u)\n", 127 nfs_callback_tcpport6, PF_INET6); 128 } else if (ret == -EAFNOSUPPORT) 129 ret = 0; 130 else 131 goto out_err; 132 #endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */ 133 134 return svc_prepare_thread(serv, &serv->sv_pools[0]); 135 136 out_err: 137 if (ret == 0) 138 ret = -ENOMEM; 139 return ERR_PTR(ret); 140 } 141 142 #if defined(CONFIG_NFS_V4_1) 143 /* 144 * The callback service for NFSv4.1 callbacks 145 */ 146 static int 147 nfs41_callback_svc(void *vrqstp) 148 { 149 struct svc_rqst *rqstp = vrqstp; 150 struct svc_serv *serv = rqstp->rq_server; 151 struct rpc_rqst *req; 152 int error; 153 DEFINE_WAIT(wq); 154 155 set_freezable(); 156 157 while (!kthread_should_stop()) { 158 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 159 spin_lock_bh(&serv->sv_cb_lock); 160 if (!list_empty(&serv->sv_cb_list)) { 161 req = list_first_entry(&serv->sv_cb_list, 162 struct rpc_rqst, rq_bc_list); 163 list_del(&req->rq_bc_list); 164 spin_unlock_bh(&serv->sv_cb_lock); 165 dprintk("Invoking bc_svc_process()\n"); 166 error = bc_svc_process(serv, req, rqstp); 167 dprintk("bc_svc_process() returned w/ error code= %d\n", 168 error); 169 } else { 170 spin_unlock_bh(&serv->sv_cb_lock); 171 schedule(); 172 } 173 finish_wait(&serv->sv_cb_waitq, &wq); 174 } 175 return 0; 176 } 177 178 /* 179 * Bring up the NFSv4.1 callback service 180 */ 181 struct svc_rqst * 182 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) 183 { 184 struct svc_xprt *bc_xprt; 185 struct svc_rqst *rqstp = ERR_PTR(-ENOMEM); 186 187 dprintk("--> %s\n", __func__); 188 /* Create a svc_sock for the service */ 189 bc_xprt = svc_sock_create(serv, xprt->prot); 190 if (!bc_xprt) 191 goto out; 192 193 /* 194 * Save the svc_serv in the transport so that it can 195 * be referenced when the session backchannel is initialized 196 */ 197 serv->bc_xprt = bc_xprt; 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]); 204 if (IS_ERR(rqstp)) 205 svc_sock_destroy(bc_xprt); 206 out: 207 dprintk("--> %s return %p\n", __func__, rqstp); 208 return rqstp; 209 } 210 211 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 212 struct svc_serv *serv, struct rpc_xprt *xprt, 213 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 214 { 215 if (minorversion) { 216 *rqstpp = nfs41_callback_up(serv, xprt); 217 *callback_svc = nfs41_callback_svc; 218 } 219 return minorversion; 220 } 221 222 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 223 struct nfs_callback_data *cb_info) 224 { 225 if (minorversion) 226 xprt->bc_serv = cb_info->serv; 227 } 228 #else 229 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 230 struct svc_serv *serv, struct rpc_xprt *xprt, 231 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 232 { 233 return 0; 234 } 235 236 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 237 struct nfs_callback_data *cb_info) 238 { 239 } 240 #endif /* CONFIG_NFS_V4_1 */ 241 242 /* 243 * Bring up the callback thread if it is not already up. 244 */ 245 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 246 { 247 struct svc_serv *serv = NULL; 248 struct svc_rqst *rqstp; 249 int (*callback_svc)(void *vrqstp); 250 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 251 char svc_name[12]; 252 int ret = 0; 253 int minorversion_setup; 254 255 mutex_lock(&nfs_callback_mutex); 256 if (cb_info->users++ || cb_info->task != NULL) { 257 nfs_callback_bc_serv(minorversion, xprt, cb_info); 258 goto out; 259 } 260 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 261 if (!serv) { 262 ret = -ENOMEM; 263 goto out_err; 264 } 265 266 minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion, 267 serv, xprt, &rqstp, &callback_svc); 268 if (!minorversion_setup) { 269 /* v4.0 callback setup */ 270 rqstp = nfs4_callback_up(serv); 271 callback_svc = nfs4_callback_svc; 272 } 273 274 if (IS_ERR(rqstp)) { 275 ret = PTR_ERR(rqstp); 276 goto out_err; 277 } 278 279 svc_sock_update_bufs(serv); 280 281 sprintf(svc_name, "nfsv4.%u-svc", minorversion); 282 cb_info->serv = serv; 283 cb_info->rqst = rqstp; 284 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); 285 if (IS_ERR(cb_info->task)) { 286 ret = PTR_ERR(cb_info->task); 287 svc_exit_thread(cb_info->rqst); 288 cb_info->rqst = NULL; 289 cb_info->task = NULL; 290 goto out_err; 291 } 292 out: 293 /* 294 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 295 * svc_prepare_thread increments that. So we need to call svc_destroy 296 * on both success and failure so that the refcount is 1 when the 297 * thread exits. 298 */ 299 if (serv) 300 svc_destroy(serv); 301 mutex_unlock(&nfs_callback_mutex); 302 return ret; 303 out_err: 304 dprintk("NFS: Couldn't create callback socket or server thread; " 305 "err = %d\n", ret); 306 cb_info->users--; 307 goto out; 308 } 309 310 /* 311 * Kill the callback thread if it's no longer being used. 312 */ 313 void nfs_callback_down(int minorversion) 314 { 315 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 316 317 mutex_lock(&nfs_callback_mutex); 318 cb_info->users--; 319 if (cb_info->users == 0 && cb_info->task != NULL) { 320 kthread_stop(cb_info->task); 321 svc_exit_thread(cb_info->rqst); 322 cb_info->serv = NULL; 323 cb_info->rqst = NULL; 324 cb_info->task = NULL; 325 } 326 mutex_unlock(&nfs_callback_mutex); 327 } 328 329 static int check_gss_callback_principal(struct nfs_client *clp, 330 struct svc_rqst *rqstp) 331 { 332 struct rpc_clnt *r = clp->cl_rpcclient; 333 char *p = svc_gss_principal(rqstp); 334 335 /* 336 * It might just be a normal user principal, in which case 337 * userspace won't bother to tell us the name at all. 338 */ 339 if (p == NULL) 340 return SVC_DENIED; 341 342 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 343 344 if (memcmp(p, "nfs@", 4) != 0) 345 return SVC_DENIED; 346 p += 4; 347 if (strcmp(p, r->cl_server) != 0) 348 return SVC_DENIED; 349 return SVC_OK; 350 } 351 352 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 353 { 354 struct nfs_client *clp; 355 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 356 int ret = SVC_OK; 357 358 /* Don't talk to strangers */ 359 clp = nfs_find_client(svc_addr(rqstp), 4); 360 if (clp == NULL) 361 return SVC_DROP; 362 363 dprintk("%s: %s NFSv4 callback!\n", __func__, 364 svc_print_addr(rqstp, buf, sizeof(buf))); 365 366 switch (rqstp->rq_authop->flavour) { 367 case RPC_AUTH_NULL: 368 if (rqstp->rq_proc != CB_NULL) 369 ret = SVC_DENIED; 370 break; 371 case RPC_AUTH_UNIX: 372 break; 373 case RPC_AUTH_GSS: 374 ret = check_gss_callback_principal(clp, rqstp); 375 break; 376 default: 377 ret = SVC_DENIED; 378 } 379 nfs_put_client(clp); 380 return ret; 381 } 382 383 /* 384 * Define NFS4 callback program 385 */ 386 static struct svc_version *nfs4_callback_version[] = { 387 [1] = &nfs4_callback_version1, 388 [4] = &nfs4_callback_version4, 389 }; 390 391 static struct svc_stat nfs4_callback_stats; 392 393 static struct svc_program nfs4_callback_program = { 394 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 395 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 396 .pg_vers = nfs4_callback_version, /* version table */ 397 .pg_name = "NFSv4 callback", /* service name */ 398 .pg_class = "nfs", /* authentication class */ 399 .pg_stats = &nfs4_callback_stats, 400 .pg_authenticate = nfs_callback_authenticate, 401 }; 402