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 /*
 103  * The callback service for NFSv4.1 callbacks
 104  */
 105 static int
 106 nfs41_callback_svc(void *vrqstp)
 107 {
 108         struct svc_rqst *rqstp = vrqstp;
 109         struct svc_serv *serv = rqstp->rq_server;
 110         struct rpc_rqst *req;
 111         int error;
 112         DEFINE_WAIT(wq);
 113
 114         set_freezable();
 115
 116         while (!kthread_should_stop()) {
 117                 if (try_to_freeze())
 118                         continue;
 119
 120                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 121                 spin_lock_bh(&serv->sv_cb_lock);
 122                 if (!list_empty(&serv->sv_cb_list)) {
 123                         req = list_first_entry(&serv->sv_cb_list,
 124                                         struct rpc_rqst, rq_bc_list);
 125                         list_del(&req->rq_bc_list);
 126                         spin_unlock_bh(&serv->sv_cb_lock);
 127                         finish_wait(&serv->sv_cb_waitq, &wq);
 128                         dprintk("Invoking bc_svc_process()\n");
 129                         error = bc_svc_process(serv, req, rqstp);
 130                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 131                                 error);
 132                 } else {
 133                         spin_unlock_bh(&serv->sv_cb_lock);
 134                         schedule();
 135                         finish_wait(&serv->sv_cb_waitq, &wq);
 136                 }
 137                 flush_signals(current);
 138         }
 139         return 0;
 140 }
 141
 142 /*
 143  * Bring up the NFSv4.1 callback service
 144  */
 145 static struct svc_rqst *
 146 nfs41_callback_up(struct svc_serv *serv)
 147 {
 148         struct svc_rqst *rqstp;
 149
 150         INIT_LIST_HEAD(&serv->sv_cb_list);
 151         spin_lock_init(&serv->sv_cb_lock);
 152         init_waitqueue_head(&serv->sv_cb_waitq);
 153         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 154         dprintk("--> %s return %d\n", __func__, PTR_ERR_OR_ZERO(rqstp));
 155         return rqstp;
 156 }
 157
 158 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 159                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 160 {
 161         *rqstpp = nfs41_callback_up(serv);
 162         *callback_svc = nfs41_callback_svc;
 163 }
 164
 165 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 166                 struct svc_serv *serv)
 167 {
 168         if (minorversion)
 169                 /*
 170                  * Save the svc_serv in the transport so that it can
 171                  * be referenced when the session backchannel is initialized
 172                  */
 173                 xprt->bc_serv = serv;
 174 }
 175 #else
 176 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 177                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 178 {
 179         *rqstpp = ERR_PTR(-ENOTSUPP);
 180         *callback_svc = ERR_PTR(-ENOTSUPP);
 181 }
 182
 183 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 184                 struct svc_serv *serv)
 185 {
 186 }
 187 #endif /* CONFIG_NFS_V4_1 */
 188
 189 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 190                                   struct svc_serv *serv)
 191 {
 192         struct svc_rqst *rqstp;
 193         int (*callback_svc)(void *vrqstp);
 194         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 195         int ret;
 196
 197         nfs_callback_bc_serv(minorversion, xprt, serv);
 198
 199         if (cb_info->task)
 200                 return 0;
 201
 202         switch (minorversion) {
 203         case 0:
 204                 /* v4.0 callback setup */
 205                 rqstp = nfs4_callback_up(serv);
 206                 callback_svc = nfs4_callback_svc;
 207                 break;
 208         default:
 209                 nfs_minorversion_callback_svc_setup(serv,
 210                                 &rqstp, &callback_svc);
 211         }
 212
 213         if (IS_ERR(rqstp))
 214                 return PTR_ERR(rqstp);
 215
 216         svc_sock_update_bufs(serv);
 217
 218         cb_info->serv = serv;
 219         cb_info->rqst = rqstp;
 220         cb_info->task = kthread_create(callback_svc, cb_info->rqst,
 221                                     "nfsv4.%u-svc", minorversion);
 222         if (IS_ERR(cb_info->task)) {
 223                 ret = PTR_ERR(cb_info->task);
 224                 svc_exit_thread(cb_info->rqst);
 225                 cb_info->rqst = NULL;
 226                 cb_info->task = NULL;
 227                 return ret;
 228         }
 229         rqstp->rq_task = cb_info->task;
 230         wake_up_process(cb_info->task);
 231         dprintk("nfs_callback_up: service started\n");
 232         return 0;
 233 }
 234
 235 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
 236 {
 237         struct nfs_net *nn = net_generic(net, nfs_net_id);
 238
 239         if (--nn->cb_users[minorversion])
 240                 return;
 241
 242         dprintk("NFS: destroy per-net callback data; net=%p\n", net);
 243         svc_shutdown_net(serv, net);
 244 }
 245
 246 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
 247                                struct net *net, struct rpc_xprt *xprt)
 248 {
 249         struct nfs_net *nn = net_generic(net, nfs_net_id);
 250         int ret;
 251
 252         if (nn->cb_users[minorversion]++)
 253                 return 0;
 254
 255         dprintk("NFS: create per-net callback data; net=%p\n", net);
 256
 257         ret = svc_bind(serv, net);
 258         if (ret < 0) {
 259                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 260                 goto err_bind;
 261         }
 262
 263         ret = -EPROTONOSUPPORT;
 264         if (minorversion == 0)
 265                 ret = nfs4_callback_up_net(serv, net);
 266         else if (xprt->ops->bc_up)
 267                 ret = xprt->ops->bc_up(serv, net);
 268
 269         if (ret < 0) {
 270                 printk(KERN_ERR "NFS: callback service start failed\n");
 271                 goto err_socks;
 272         }
 273         return 0;
 274
 275 err_socks:
 276         svc_rpcb_cleanup(serv, net);
 277 err_bind:
 278         dprintk("NFS: Couldn't create callback socket: err = %d; "
 279                         "net = %p\n", ret, net);
 280         return ret;
 281 }
 282
 283 static struct svc_serv_ops nfs_cb_sv_ops = {
 284         .svo_enqueue_xprt       = svc_xprt_do_enqueue,
 285 };
 286
 287 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 288 {
 289         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 290         struct svc_serv *serv;
 291
 292         /*
 293          * Check whether we're already up and running.
 294          */
 295         if (cb_info->task) {
 296                 /*
 297                  * Note: increase service usage, because later in case of error
 298                  * svc_destroy() will be called.
 299                  */
 300                 svc_get(cb_info->serv);
 301                 return cb_info->serv;
 302         }
 303
 304         /*
 305          * Sanity check: if there's no task,
 306          * we should be the first user ...
 307          */
 308         if (cb_info->users)
 309                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 310                         cb_info->users);
 311
 312         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, &nfs_cb_sv_ops);
 313         if (!serv) {
 314                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 315                 return ERR_PTR(-ENOMEM);
 316         }
 317         /* As there is only one thread we need to over-ride the
 318          * default maximum of 80 connections
 319          */
 320         serv->sv_maxconn = 1024;
 321         dprintk("nfs_callback_create_svc: service created\n");
 322         return serv;
 323 }
 324
 325 /*
 326  * Bring up the callback thread if it is not already up.
 327  */
 328 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 329 {
 330         struct svc_serv *serv;
 331         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 332         int ret;
 333         struct net *net = xprt->xprt_net;
 334
 335         mutex_lock(&nfs_callback_mutex);
 336
 337         serv = nfs_callback_create_svc(minorversion);
 338         if (IS_ERR(serv)) {
 339                 ret = PTR_ERR(serv);
 340                 goto err_create;
 341         }
 342
 343         ret = nfs_callback_up_net(minorversion, serv, net, xprt);
 344         if (ret < 0)
 345                 goto err_net;
 346
 347         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 348         if (ret < 0)
 349                 goto err_start;
 350
 351         cb_info->users++;
 352         /*
 353          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 354          * svc_prepare_thread increments that. So we need to call svc_destroy
 355          * on both success and failure so that the refcount is 1 when the
 356          * thread exits.
 357          */
 358 err_net:
 359         svc_destroy(serv);
 360 err_create:
 361         mutex_unlock(&nfs_callback_mutex);
 362         return ret;
 363
 364 err_start:
 365         nfs_callback_down_net(minorversion, serv, net);
 366         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 367         goto err_net;
 368 }
 369
 370 /*
 371  * Kill the callback thread if it's no longer being used.
 372  */
 373 void nfs_callback_down(int minorversion, struct net *net)
 374 {
 375         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 376
 377         mutex_lock(&nfs_callback_mutex);
 378         nfs_callback_down_net(minorversion, cb_info->serv, net);
 379         cb_info->users--;
 380         if (cb_info->users == 0 && cb_info->task != NULL) {
 381                 kthread_stop(cb_info->task);
 382                 dprintk("nfs_callback_down: service stopped\n");
 383                 svc_exit_thread(cb_info->rqst);
 384                 dprintk("nfs_callback_down: service destroyed\n");
 385                 cb_info->serv = NULL;
 386                 cb_info->rqst = NULL;
 387                 cb_info->task = NULL;
 388         }
 389         mutex_unlock(&nfs_callback_mutex);
 390 }
 391
 392 /* Boolean check of RPC_AUTH_GSS principal */
 393 int
 394 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 395 {
 396         char *p = rqstp->rq_cred.cr_principal;
 397
 398         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 399                 return 1;
 400
 401         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 402         if (clp->cl_minorversion != 0)
 403                 return 0;
 404         /*
 405          * It might just be a normal user principal, in which case
 406          * userspace won't bother to tell us the name at all.
 407          */
 408         if (p == NULL)
 409                 return 0;
 410
 411         /*
 412          * Did we get the acceptor from userland during the SETCLIENID
 413          * negotiation?
 414          */
 415         if (clp->cl_acceptor)
 416                 return !strcmp(p, clp->cl_acceptor);
 417
 418         /*
 419          * Otherwise try to verify it using the cl_hostname. Note that this
 420          * doesn't work if a non-canonical hostname was used in the devname.
 421          */
 422
 423         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 424
 425         if (memcmp(p, "nfs@", 4) != 0)
 426                 return 0;
 427         p += 4;
 428         if (strcmp(p, clp->cl_hostname) != 0)
 429                 return 0;
 430         return 1;
 431 }
 432
 433 /*
 434  * pg_authenticate method for nfsv4 callback threads.
 435  *
 436  * The authflavor has been negotiated, so an incorrect flavor is a server
 437  * bug. Deny packets with incorrect authflavor.
 438  *
 439  * All other checking done after NFS decoding where the nfs_client can be
 440  * found in nfs4_callback_compound
 441  */
 442 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 443 {
 444         switch (rqstp->rq_authop->flavour) {
 445         case RPC_AUTH_NULL:
 446                 if (rqstp->rq_proc != CB_NULL)
 447                         return SVC_DENIED;
 448                 break;
 449         case RPC_AUTH_GSS:
 450                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 451                  if (svc_is_backchannel(rqstp))
 452                         return SVC_DENIED;
 453         }
 454         return SVC_OK;
 455 }
 456
 457 /*
 458  * Define NFS4 callback program
 459  */
 460 static struct svc_version *nfs4_callback_version[] = {
 461         [1] = &nfs4_callback_version1,
 462         [4] = &nfs4_callback_version4,
 463 };
 464
 465 static struct svc_stat nfs4_callback_stats;
 466
 467 static struct svc_program nfs4_callback_program = {
 468         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 469         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 470         .pg_vers = nfs4_callback_version,               /* version table */
 471         .pg_name = "NFSv4 callback",                    /* service name */
 472         .pg_class = "nfs",                              /* authentication class */
 473         .pg_stats = &nfs4_callback_stats,
 474         .pg_authenticate = nfs_callback_authenticate,
 475 };