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