fs/nfs/callback.c

   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                         finish_wait(&serv->sv_cb_waitq, &wq);
 139                         dprintk("Invoking bc_svc_process()\n");
 140                         error = bc_svc_process(serv, req, rqstp);
 141                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 142                                 error);
 143                 } else {
 144                         spin_unlock_bh(&serv->sv_cb_lock);
 145                         schedule();
 146                         finish_wait(&serv->sv_cb_waitq, &wq);
 147                 }
 148                 flush_signals(current);
 149         }
 150         return 0;
 151 }
 152
 153 /*
 154  * Bring up the NFSv4.1 callback service
 155  */
 156 static struct svc_rqst *
 157 nfs41_callback_up(struct svc_serv *serv)
 158 {
 159         struct svc_rqst *rqstp;
 160
 161         INIT_LIST_HEAD(&serv->sv_cb_list);
 162         spin_lock_init(&serv->sv_cb_lock);
 163         init_waitqueue_head(&serv->sv_cb_waitq);
 164         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 165         if (IS_ERR(rqstp)) {
 166                 svc_xprt_put(serv->sv_bc_xprt);
 167                 serv->sv_bc_xprt = NULL;
 168         }
 169         dprintk("--> %s return %d\n", __func__, PTR_ERR_OR_ZERO(rqstp));
 170         return rqstp;
 171 }
 172
 173 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 174                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 175 {
 176         *rqstpp = nfs41_callback_up(serv);
 177         *callback_svc = nfs41_callback_svc;
 178 }
 179
 180 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 181                 struct svc_serv *serv)
 182 {
 183         if (minorversion)
 184                 /*
 185                  * Save the svc_serv in the transport so that it can
 186                  * be referenced when the session backchannel is initialized
 187                  */
 188                 xprt->bc_serv = serv;
 189 }
 190 #else
 191 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 192 {
 193         return 0;
 194 }
 195
 196 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 197                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 198 {
 199         *rqstpp = ERR_PTR(-ENOTSUPP);
 200         *callback_svc = ERR_PTR(-ENOTSUPP);
 201 }
 202
 203 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 204                 struct svc_serv *serv)
 205 {
 206 }
 207 #endif /* CONFIG_NFS_V4_1 */
 208
 209 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 210                                   struct svc_serv *serv)
 211 {
 212         struct svc_rqst *rqstp;
 213         int (*callback_svc)(void *vrqstp);
 214         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 215         int ret;
 216
 217         nfs_callback_bc_serv(minorversion, xprt, serv);
 218
 219         if (cb_info->task)
 220                 return 0;
 221
 222         switch (minorversion) {
 223         case 0:
 224                 /* v4.0 callback setup */
 225                 rqstp = nfs4_callback_up(serv);
 226                 callback_svc = nfs4_callback_svc;
 227                 break;
 228         default:
 229                 nfs_minorversion_callback_svc_setup(serv,
 230                                 &rqstp, &callback_svc);
 231         }
 232
 233         if (IS_ERR(rqstp))
 234                 return PTR_ERR(rqstp);
 235
 236         svc_sock_update_bufs(serv);
 237
 238         cb_info->serv = serv;
 239         cb_info->rqst = rqstp;
 240         cb_info->task = kthread_create(callback_svc, cb_info->rqst,
 241                                     "nfsv4.%u-svc", minorversion);
 242         if (IS_ERR(cb_info->task)) {
 243                 ret = PTR_ERR(cb_info->task);
 244                 svc_exit_thread(cb_info->rqst);
 245                 cb_info->rqst = NULL;
 246                 cb_info->task = NULL;
 247                 return ret;
 248         }
 249         rqstp->rq_task = cb_info->task;
 250         wake_up_process(cb_info->task);
 251         dprintk("nfs_callback_up: service started\n");
 252         return 0;
 253 }
 254
 255 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
 256 {
 257         struct nfs_net *nn = net_generic(net, nfs_net_id);
 258
 259         if (--nn->cb_users[minorversion])
 260                 return;
 261
 262         dprintk("NFS: destroy per-net callback data; net=%p\n", net);
 263         svc_shutdown_net(serv, net);
 264 }
 265
 266 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 267 {
 268         struct nfs_net *nn = net_generic(net, nfs_net_id);
 269         int ret;
 270
 271         if (nn->cb_users[minorversion]++)
 272                 return 0;
 273
 274         dprintk("NFS: create per-net callback data; net=%p\n", net);
 275
 276         ret = svc_bind(serv, net);
 277         if (ret < 0) {
 278                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 279                 goto err_bind;
 280         }
 281
 282         switch (minorversion) {
 283                 case 0:
 284                         ret = nfs4_callback_up_net(serv, net);
 285                         break;
 286                 case 1:
 287                 case 2:
 288                         ret = nfs41_callback_up_net(serv, net);
 289                         break;
 290                 default:
 291                         printk(KERN_ERR "NFS: unknown callback version: %d\n",
 292                                         minorversion);
 293                         ret = -EINVAL;
 294                         break;
 295         }
 296
 297         if (ret < 0) {
 298                 printk(KERN_ERR "NFS: callback service start failed\n");
 299                 goto err_socks;
 300         }
 301         return 0;
 302
 303 err_socks:
 304         svc_rpcb_cleanup(serv, net);
 305 err_bind:
 306         dprintk("NFS: Couldn't create callback socket: err = %d; "
 307                         "net = %p\n", ret, net);
 308         return ret;
 309 }
 310
 311 static struct svc_serv_ops nfs_cb_sv_ops = {
 312         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
 313 };
 314
 315 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 316 {
 317         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 318         struct svc_serv *serv;
 319
 320         /*
 321          * Check whether we're already up and running.
 322          */
 323         if (cb_info->task) {
 324                 /*
 325                  * Note: increase service usage, because later in case of error
 326                  * svc_destroy() will be called.
 327                  */
 328                 svc_get(cb_info->serv);
 329                 return cb_info->serv;
 330         }
 331
 332         /*
 333          * Sanity check: if there's no task,
 334          * we should be the first user ...
 335          */
 336         if (cb_info->users)
 337                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 338                         cb_info->users);
 339
 340         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, &nfs_cb_sv_ops);
 341         if (!serv) {
 342                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 343                 return ERR_PTR(-ENOMEM);
 344         }
 345         /* As there is only one thread we need to over-ride the
 346          * default maximum of 80 connections
 347          */
 348         serv->sv_maxconn = 1024;
 349         dprintk("nfs_callback_create_svc: service created\n");
 350         return serv;
 351 }
 352
 353 /*
 354  * Bring up the callback thread if it is not already up.
 355  */
 356 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 357 {
 358         struct svc_serv *serv;
 359         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 360         int ret;
 361         struct net *net = xprt->xprt_net;
 362
 363         mutex_lock(&nfs_callback_mutex);
 364
 365         serv = nfs_callback_create_svc(minorversion);
 366         if (IS_ERR(serv)) {
 367                 ret = PTR_ERR(serv);
 368                 goto err_create;
 369         }
 370
 371         ret = nfs_callback_up_net(minorversion, serv, net);
 372         if (ret < 0)
 373                 goto err_net;
 374
 375         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 376         if (ret < 0)
 377                 goto err_start;
 378
 379         cb_info->users++;
 380         /*
 381          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 382          * svc_prepare_thread increments that. So we need to call svc_destroy
 383          * on both success and failure so that the refcount is 1 when the
 384          * thread exits.
 385          */
 386 err_net:
 387         svc_destroy(serv);
 388 err_create:
 389         mutex_unlock(&nfs_callback_mutex);
 390         return ret;
 391
 392 err_start:
 393         nfs_callback_down_net(minorversion, serv, net);
 394         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 395         goto err_net;
 396 }
 397
 398 /*
 399  * Kill the callback thread if it's no longer being used.
 400  */
 401 void nfs_callback_down(int minorversion, struct net *net)
 402 {
 403         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 404
 405         mutex_lock(&nfs_callback_mutex);
 406         nfs_callback_down_net(minorversion, cb_info->serv, net);
 407         cb_info->users--;
 408         if (cb_info->users == 0 && cb_info->task != NULL) {
 409                 kthread_stop(cb_info->task);
 410                 dprintk("nfs_callback_down: service stopped\n");
 411                 svc_exit_thread(cb_info->rqst);
 412                 dprintk("nfs_callback_down: service destroyed\n");
 413                 cb_info->serv = NULL;
 414                 cb_info->rqst = NULL;
 415                 cb_info->task = NULL;
 416         }
 417         mutex_unlock(&nfs_callback_mutex);
 418 }
 419
 420 /* Boolean check of RPC_AUTH_GSS principal */
 421 int
 422 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 423 {
 424         char *p = rqstp->rq_cred.cr_principal;
 425
 426         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 427                 return 1;
 428
 429         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 430         if (clp->cl_minorversion != 0)
 431                 return 0;
 432         /*
 433          * It might just be a normal user principal, in which case
 434          * userspace won't bother to tell us the name at all.
 435          */
 436         if (p == NULL)
 437                 return 0;
 438
 439         /*
 440          * Did we get the acceptor from userland during the SETCLIENID
 441          * negotiation?
 442          */
 443         if (clp->cl_acceptor)
 444                 return !strcmp(p, clp->cl_acceptor);
 445
 446         /*
 447          * Otherwise try to verify it using the cl_hostname. Note that this
 448          * doesn't work if a non-canonical hostname was used in the devname.
 449          */
 450
 451         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 452
 453         if (memcmp(p, "nfs@", 4) != 0)
 454                 return 0;
 455         p += 4;
 456         if (strcmp(p, clp->cl_hostname) != 0)
 457                 return 0;
 458         return 1;
 459 }
 460
 461 /*
 462  * pg_authenticate method for nfsv4 callback threads.
 463  *
 464  * The authflavor has been negotiated, so an incorrect flavor is a server
 465  * bug. Deny packets with incorrect authflavor.
 466  *
 467  * All other checking done after NFS decoding where the nfs_client can be
 468  * found in nfs4_callback_compound
 469  */
 470 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 471 {
 472         switch (rqstp->rq_authop->flavour) {
 473         case RPC_AUTH_NULL:
 474                 if (rqstp->rq_proc != CB_NULL)
 475                         return SVC_DENIED;
 476                 break;
 477         case RPC_AUTH_GSS:
 478                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 479                  if (svc_is_backchannel(rqstp))
 480                         return SVC_DENIED;
 481         }
 482         return SVC_OK;
 483 }
 484
 485 /*
 486  * Define NFS4 callback program
 487  */
 488 static struct svc_version *nfs4_callback_version[] = {
 489         [1] = &nfs4_callback_version1,
 490         [4] = &nfs4_callback_version4,
 491 };
 492
 493 static struct svc_stat nfs4_callback_stats;
 494
 495 static struct svc_program nfs4_callback_program = {
 496         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 497         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 498         .pg_vers = nfs4_callback_version,               /* version table */
 499         .pg_name = "NFSv4 callback",                    /* service name */
 500         .pg_class = "nfs",                              /* authentication class */
 501         .pg_stats = &nfs4_callback_stats,
 502         .pg_authenticate = nfs_callback_authenticate,
 503 };