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, const 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 static struct kernel_param_ops param_ops_portnr = { 62 .set = param_set_portnr, 63 .get = param_get_uint, 64 }; 65 #define param_check_portnr(name, p) __param_check(name, p, unsigned int); 66 67 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644); 68 69 /* 70 * This is the NFSv4 callback kernel thread. 71 */ 72 static int 73 nfs4_callback_svc(void *vrqstp) 74 { 75 int err, preverr = 0; 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 preverr = err; 87 continue; 88 } 89 if (err < 0) { 90 if (err != preverr) { 91 printk(KERN_WARNING "%s: unexpected error " 92 "from svc_recv (%d)\n", __func__, err); 93 preverr = err; 94 } 95 schedule_timeout_uninterruptible(HZ); 96 continue; 97 } 98 preverr = err; 99 svc_process(rqstp); 100 } 101 return 0; 102 } 103 104 /* 105 * Prepare to bring up the NFSv4 callback service 106 */ 107 struct svc_rqst * 108 nfs4_callback_up(struct svc_serv *serv) 109 { 110 int ret; 111 112 ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET, 113 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 114 if (ret <= 0) 115 goto out_err; 116 nfs_callback_tcpport = ret; 117 dprintk("NFS: Callback listener port = %u (af %u)\n", 118 nfs_callback_tcpport, PF_INET); 119 120 ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET6, 121 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 122 if (ret > 0) { 123 nfs_callback_tcpport6 = ret; 124 dprintk("NFS: Callback listener port = %u (af %u)\n", 125 nfs_callback_tcpport6, PF_INET6); 126 } else if (ret == -EAFNOSUPPORT) 127 ret = 0; 128 else 129 goto out_err; 130 131 return svc_prepare_thread(serv, &serv->sv_pools[0]); 132 133 out_err: 134 if (ret == 0) 135 ret = -ENOMEM; 136 return ERR_PTR(ret); 137 } 138 139 #if defined(CONFIG_NFS_V4_1) 140 /* 141 * The callback service for NFSv4.1 callbacks 142 */ 143 static int 144 nfs41_callback_svc(void *vrqstp) 145 { 146 struct svc_rqst *rqstp = vrqstp; 147 struct svc_serv *serv = rqstp->rq_server; 148 struct rpc_rqst *req; 149 int error; 150 DEFINE_WAIT(wq); 151 152 set_freezable(); 153 154 while (!kthread_should_stop()) { 155 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 156 spin_lock_bh(&serv->sv_cb_lock); 157 if (!list_empty(&serv->sv_cb_list)) { 158 req = list_first_entry(&serv->sv_cb_list, 159 struct rpc_rqst, rq_bc_list); 160 list_del(&req->rq_bc_list); 161 spin_unlock_bh(&serv->sv_cb_lock); 162 dprintk("Invoking bc_svc_process()\n"); 163 error = bc_svc_process(serv, req, rqstp); 164 dprintk("bc_svc_process() returned w/ error code= %d\n", 165 error); 166 } else { 167 spin_unlock_bh(&serv->sv_cb_lock); 168 schedule(); 169 } 170 finish_wait(&serv->sv_cb_waitq, &wq); 171 } 172 return 0; 173 } 174 175 /* 176 * Bring up the NFSv4.1 callback service 177 */ 178 struct svc_rqst * 179 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) 180 { 181 struct svc_xprt *bc_xprt; 182 struct svc_rqst *rqstp = ERR_PTR(-ENOMEM); 183 184 dprintk("--> %s\n", __func__); 185 /* Create a svc_sock for the service */ 186 bc_xprt = svc_sock_create(serv, xprt->prot); 187 if (!bc_xprt) 188 goto out; 189 190 /* 191 * Save the svc_serv in the transport so that it can 192 * be referenced when the session backchannel is initialized 193 */ 194 serv->bc_xprt = bc_xprt; 195 xprt->bc_serv = serv; 196 197 INIT_LIST_HEAD(&serv->sv_cb_list); 198 spin_lock_init(&serv->sv_cb_lock); 199 init_waitqueue_head(&serv->sv_cb_waitq); 200 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]); 201 if (IS_ERR(rqstp)) 202 svc_sock_destroy(bc_xprt); 203 out: 204 dprintk("--> %s return %p\n", __func__, rqstp); 205 return rqstp; 206 } 207 208 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 209 struct svc_serv *serv, struct rpc_xprt *xprt, 210 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 211 { 212 if (minorversion) { 213 *rqstpp = nfs41_callback_up(serv, xprt); 214 *callback_svc = nfs41_callback_svc; 215 } 216 return minorversion; 217 } 218 219 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 220 struct nfs_callback_data *cb_info) 221 { 222 if (minorversion) 223 xprt->bc_serv = cb_info->serv; 224 } 225 #else 226 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 227 struct svc_serv *serv, struct rpc_xprt *xprt, 228 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 229 { 230 return 0; 231 } 232 233 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 234 struct nfs_callback_data *cb_info) 235 { 236 } 237 #endif /* CONFIG_NFS_V4_1 */ 238 239 /* 240 * Bring up the callback thread if it is not already up. 241 */ 242 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 243 { 244 struct svc_serv *serv = NULL; 245 struct svc_rqst *rqstp; 246 int (*callback_svc)(void *vrqstp); 247 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 248 char svc_name[12]; 249 int ret = 0; 250 int minorversion_setup; 251 252 mutex_lock(&nfs_callback_mutex); 253 if (cb_info->users++ || cb_info->task != NULL) { 254 nfs_callback_bc_serv(minorversion, xprt, cb_info); 255 goto out; 256 } 257 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 258 if (!serv) { 259 ret = -ENOMEM; 260 goto out_err; 261 } 262 263 minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion, 264 serv, xprt, &rqstp, &callback_svc); 265 if (!minorversion_setup) { 266 /* v4.0 callback setup */ 267 rqstp = nfs4_callback_up(serv); 268 callback_svc = nfs4_callback_svc; 269 } 270 271 if (IS_ERR(rqstp)) { 272 ret = PTR_ERR(rqstp); 273 goto out_err; 274 } 275 276 svc_sock_update_bufs(serv); 277 278 sprintf(svc_name, "nfsv4.%u-svc", minorversion); 279 cb_info->serv = serv; 280 cb_info->rqst = rqstp; 281 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); 282 if (IS_ERR(cb_info->task)) { 283 ret = PTR_ERR(cb_info->task); 284 svc_exit_thread(cb_info->rqst); 285 cb_info->rqst = NULL; 286 cb_info->task = NULL; 287 goto out_err; 288 } 289 out: 290 /* 291 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 292 * svc_prepare_thread increments that. So we need to call svc_destroy 293 * on both success and failure so that the refcount is 1 when the 294 * thread exits. 295 */ 296 if (serv) 297 svc_destroy(serv); 298 mutex_unlock(&nfs_callback_mutex); 299 return ret; 300 out_err: 301 dprintk("NFS: Couldn't create callback socket or server thread; " 302 "err = %d\n", ret); 303 cb_info->users--; 304 goto out; 305 } 306 307 /* 308 * Kill the callback thread if it's no longer being used. 309 */ 310 void nfs_callback_down(int minorversion) 311 { 312 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 313 314 mutex_lock(&nfs_callback_mutex); 315 cb_info->users--; 316 if (cb_info->users == 0 && cb_info->task != NULL) { 317 kthread_stop(cb_info->task); 318 svc_exit_thread(cb_info->rqst); 319 cb_info->serv = NULL; 320 cb_info->rqst = NULL; 321 cb_info->task = NULL; 322 } 323 mutex_unlock(&nfs_callback_mutex); 324 } 325 326 static int check_gss_callback_principal(struct nfs_client *clp, 327 struct svc_rqst *rqstp) 328 { 329 struct rpc_clnt *r = clp->cl_rpcclient; 330 char *p = svc_gss_principal(rqstp); 331 332 /* 333 * It might just be a normal user principal, in which case 334 * userspace won't bother to tell us the name at all. 335 */ 336 if (p == NULL) 337 return SVC_DENIED; 338 339 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 340 341 if (memcmp(p, "nfs@", 4) != 0) 342 return SVC_DENIED; 343 p += 4; 344 if (strcmp(p, r->cl_server) != 0) 345 return SVC_DENIED; 346 return SVC_OK; 347 } 348 349 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 350 { 351 struct nfs_client *clp; 352 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 353 int ret = SVC_OK; 354 355 /* Don't talk to strangers */ 356 clp = nfs_find_client(svc_addr(rqstp), 4); 357 if (clp == NULL) 358 return SVC_DROP; 359 360 dprintk("%s: %s NFSv4 callback!\n", __func__, 361 svc_print_addr(rqstp, buf, sizeof(buf))); 362 363 switch (rqstp->rq_authop->flavour) { 364 case RPC_AUTH_NULL: 365 if (rqstp->rq_proc != CB_NULL) 366 ret = SVC_DENIED; 367 break; 368 case RPC_AUTH_UNIX: 369 break; 370 case RPC_AUTH_GSS: 371 ret = check_gss_callback_principal(clp, rqstp); 372 break; 373 default: 374 ret = SVC_DENIED; 375 } 376 nfs_put_client(clp); 377 return ret; 378 } 379 380 /* 381 * Define NFS4 callback program 382 */ 383 static struct svc_version *nfs4_callback_version[] = { 384 [1] = &nfs4_callback_version1, 385 [4] = &nfs4_callback_version4, 386 }; 387 388 static struct svc_stat nfs4_callback_stats; 389 390 static struct svc_program nfs4_callback_program = { 391 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 392 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 393 .pg_vers = nfs4_callback_version, /* version table */ 394 .pg_name = "NFSv4 callback", /* service name */ 395 .pg_class = "nfs", /* authentication class */ 396 .pg_stats = &nfs4_callback_stats, 397 .pg_authenticate = nfs_callback_authenticate, 398 }; 399