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/mutex.h> 16 #include <linux/freezer.h> 17 #include <linux/kthread.h> 18 #include <linux/sunrpc/svcauth_gss.h> 19 #if defined(CONFIG_NFS_V4_1) 20 #include <linux/sunrpc/bc_xprt.h> 21 #endif 22 23 #include <net/inet_sock.h> 24 25 #include "nfs4_fs.h" 26 #include "callback.h" 27 #include "internal.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 unsigned int nfs_callback_set_tcpport; 43 unsigned short nfs_callback_tcpport; 44 unsigned short nfs_callback_tcpport6; 45 #define NFS_CALLBACK_MAXPORTNR (65535U) 46 47 static int param_set_portnr(const char *val, const struct kernel_param *kp) 48 { 49 unsigned long num; 50 int ret; 51 52 if (!val) 53 return -EINVAL; 54 ret = strict_strtoul(val, 0, &num); 55 if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR) 56 return -EINVAL; 57 *((unsigned int *)kp->arg) = num; 58 return 0; 59 } 60 static struct kernel_param_ops param_ops_portnr = { 61 .set = param_set_portnr, 62 .get = param_get_uint, 63 }; 64 #define param_check_portnr(name, p) __param_check(name, p, unsigned int); 65 66 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644); 67 68 /* 69 * This is the NFSv4 callback kernel thread. 70 */ 71 static int 72 nfs4_callback_svc(void *vrqstp) 73 { 74 int err, preverr = 0; 75 struct svc_rqst *rqstp = vrqstp; 76 77 set_freezable(); 78 79 while (!kthread_should_stop()) { 80 /* 81 * Listen for a request on the socket 82 */ 83 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); 84 if (err == -EAGAIN || err == -EINTR) { 85 preverr = err; 86 continue; 87 } 88 if (err < 0) { 89 if (err != preverr) { 90 printk(KERN_WARNING "%s: unexpected error " 91 "from svc_recv (%d)\n", __func__, err); 92 preverr = err; 93 } 94 schedule_timeout_uninterruptible(HZ); 95 continue; 96 } 97 preverr = err; 98 svc_process(rqstp); 99 } 100 return 0; 101 } 102 103 /* 104 * Prepare to bring up the NFSv4 callback service 105 */ 106 struct svc_rqst * 107 nfs4_callback_up(struct svc_serv *serv) 108 { 109 int ret; 110 111 ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET, 112 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 113 if (ret <= 0) 114 goto out_err; 115 nfs_callback_tcpport = ret; 116 dprintk("NFS: Callback listener port = %u (af %u)\n", 117 nfs_callback_tcpport, PF_INET); 118 119 ret = svc_create_xprt(serv, "tcp", &init_net, PF_INET6, 120 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS); 121 if (ret > 0) { 122 nfs_callback_tcpport6 = ret; 123 dprintk("NFS: Callback listener port = %u (af %u)\n", 124 nfs_callback_tcpport6, PF_INET6); 125 } else if (ret == -EAFNOSUPPORT) 126 ret = 0; 127 else 128 goto out_err; 129 130 return svc_prepare_thread(serv, &serv->sv_pools[0]); 131 132 out_err: 133 if (ret == 0) 134 ret = -ENOMEM; 135 return ERR_PTR(ret); 136 } 137 138 #if defined(CONFIG_NFS_V4_1) 139 /* 140 * The callback service for NFSv4.1 callbacks 141 */ 142 static int 143 nfs41_callback_svc(void *vrqstp) 144 { 145 struct svc_rqst *rqstp = vrqstp; 146 struct svc_serv *serv = rqstp->rq_server; 147 struct rpc_rqst *req; 148 int error; 149 DEFINE_WAIT(wq); 150 151 set_freezable(); 152 153 while (!kthread_should_stop()) { 154 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE); 155 spin_lock_bh(&serv->sv_cb_lock); 156 if (!list_empty(&serv->sv_cb_list)) { 157 req = list_first_entry(&serv->sv_cb_list, 158 struct rpc_rqst, rq_bc_list); 159 list_del(&req->rq_bc_list); 160 spin_unlock_bh(&serv->sv_cb_lock); 161 dprintk("Invoking bc_svc_process()\n"); 162 error = bc_svc_process(serv, req, rqstp); 163 dprintk("bc_svc_process() returned w/ error code= %d\n", 164 error); 165 } else { 166 spin_unlock_bh(&serv->sv_cb_lock); 167 schedule(); 168 } 169 finish_wait(&serv->sv_cb_waitq, &wq); 170 } 171 return 0; 172 } 173 174 /* 175 * Bring up the NFSv4.1 callback service 176 */ 177 struct svc_rqst * 178 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt) 179 { 180 struct svc_xprt *bc_xprt; 181 struct svc_rqst *rqstp = ERR_PTR(-ENOMEM); 182 183 dprintk("--> %s\n", __func__); 184 /* Create a svc_sock for the service */ 185 bc_xprt = svc_sock_create(serv, xprt->prot); 186 if (!bc_xprt) 187 goto out; 188 189 /* 190 * Save the svc_serv in the transport so that it can 191 * be referenced when the session backchannel is initialized 192 */ 193 serv->bc_xprt = bc_xprt; 194 xprt->bc_serv = serv; 195 196 INIT_LIST_HEAD(&serv->sv_cb_list); 197 spin_lock_init(&serv->sv_cb_lock); 198 init_waitqueue_head(&serv->sv_cb_waitq); 199 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]); 200 if (IS_ERR(rqstp)) 201 svc_sock_destroy(bc_xprt); 202 out: 203 dprintk("--> %s return %p\n", __func__, rqstp); 204 return rqstp; 205 } 206 207 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 208 struct svc_serv *serv, struct rpc_xprt *xprt, 209 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 210 { 211 if (minorversion) { 212 *rqstpp = nfs41_callback_up(serv, xprt); 213 *callback_svc = nfs41_callback_svc; 214 } 215 return minorversion; 216 } 217 218 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 219 struct nfs_callback_data *cb_info) 220 { 221 if (minorversion) 222 xprt->bc_serv = cb_info->serv; 223 } 224 #else 225 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion, 226 struct svc_serv *serv, struct rpc_xprt *xprt, 227 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp)) 228 { 229 return 0; 230 } 231 232 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt, 233 struct nfs_callback_data *cb_info) 234 { 235 } 236 #endif /* CONFIG_NFS_V4_1 */ 237 238 /* 239 * Bring up the callback thread if it is not already up. 240 */ 241 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt) 242 { 243 struct svc_serv *serv = NULL; 244 struct svc_rqst *rqstp; 245 int (*callback_svc)(void *vrqstp); 246 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 247 char svc_name[12]; 248 int ret = 0; 249 int minorversion_setup; 250 251 mutex_lock(&nfs_callback_mutex); 252 if (cb_info->users++ || cb_info->task != NULL) { 253 nfs_callback_bc_serv(minorversion, xprt, cb_info); 254 goto out; 255 } 256 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 257 if (!serv) { 258 ret = -ENOMEM; 259 goto out_err; 260 } 261 262 minorversion_setup = nfs_minorversion_callback_svc_setup(minorversion, 263 serv, xprt, &rqstp, &callback_svc); 264 if (!minorversion_setup) { 265 /* v4.0 callback setup */ 266 rqstp = nfs4_callback_up(serv); 267 callback_svc = nfs4_callback_svc; 268 } 269 270 if (IS_ERR(rqstp)) { 271 ret = PTR_ERR(rqstp); 272 goto out_err; 273 } 274 275 svc_sock_update_bufs(serv); 276 277 sprintf(svc_name, "nfsv4.%u-svc", minorversion); 278 cb_info->serv = serv; 279 cb_info->rqst = rqstp; 280 cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name); 281 if (IS_ERR(cb_info->task)) { 282 ret = PTR_ERR(cb_info->task); 283 svc_exit_thread(cb_info->rqst); 284 cb_info->rqst = NULL; 285 cb_info->task = NULL; 286 goto out_err; 287 } 288 out: 289 /* 290 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 291 * svc_prepare_thread increments that. So we need to call svc_destroy 292 * on both success and failure so that the refcount is 1 when the 293 * thread exits. 294 */ 295 if (serv) 296 svc_destroy(serv); 297 mutex_unlock(&nfs_callback_mutex); 298 return ret; 299 out_err: 300 dprintk("NFS: Couldn't create callback socket or server thread; " 301 "err = %d\n", ret); 302 cb_info->users--; 303 goto out; 304 } 305 306 /* 307 * Kill the callback thread if it's no longer being used. 308 */ 309 void nfs_callback_down(int minorversion) 310 { 311 struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion]; 312 313 mutex_lock(&nfs_callback_mutex); 314 cb_info->users--; 315 if (cb_info->users == 0 && cb_info->task != NULL) { 316 kthread_stop(cb_info->task); 317 svc_exit_thread(cb_info->rqst); 318 cb_info->serv = NULL; 319 cb_info->rqst = NULL; 320 cb_info->task = NULL; 321 } 322 mutex_unlock(&nfs_callback_mutex); 323 } 324 325 static int check_gss_callback_principal(struct nfs_client *clp, 326 struct svc_rqst *rqstp) 327 { 328 struct rpc_clnt *r = clp->cl_rpcclient; 329 char *p = svc_gss_principal(rqstp); 330 331 /* 332 * It might just be a normal user principal, in which case 333 * userspace won't bother to tell us the name at all. 334 */ 335 if (p == NULL) 336 return SVC_DENIED; 337 338 /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */ 339 340 if (memcmp(p, "nfs@", 4) != 0) 341 return SVC_DENIED; 342 p += 4; 343 if (strcmp(p, r->cl_server) != 0) 344 return SVC_DENIED; 345 return SVC_OK; 346 } 347 348 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 349 { 350 struct nfs_client *clp; 351 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 352 int ret = SVC_OK; 353 354 /* Don't talk to strangers */ 355 clp = nfs_find_client(svc_addr(rqstp), 4); 356 if (clp == NULL) 357 return SVC_DROP; 358 359 dprintk("%s: %s NFSv4 callback!\n", __func__, 360 svc_print_addr(rqstp, buf, sizeof(buf))); 361 362 switch (rqstp->rq_authop->flavour) { 363 case RPC_AUTH_NULL: 364 if (rqstp->rq_proc != CB_NULL) 365 ret = SVC_DENIED; 366 break; 367 case RPC_AUTH_UNIX: 368 break; 369 case RPC_AUTH_GSS: 370 ret = check_gss_callback_principal(clp, rqstp); 371 break; 372 default: 373 ret = SVC_DENIED; 374 } 375 nfs_put_client(clp); 376 return ret; 377 } 378 379 /* 380 * Define NFS4 callback program 381 */ 382 static struct svc_version *nfs4_callback_version[] = { 383 [1] = &nfs4_callback_version1, 384 [4] = &nfs4_callback_version4, 385 }; 386 387 static struct svc_stat nfs4_callback_stats; 388 389 static struct svc_program nfs4_callback_program = { 390 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 391 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 392 .pg_vers = nfs4_callback_version, /* version table */ 393 .pg_name = "NFSv4 callback", /* service name */ 394 .pg_class = "nfs", /* authentication class */ 395 .pg_stats = &nfs4_callback_stats, 396 .pg_authenticate = nfs_callback_authenticate, 397 }; 398