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, 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 "NFS: %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 static struct svc_rqst *
 108 nfs4_callback_up(struct svc_serv *serv)
 109 {
 110         return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 111 }
 112
 113 #if defined(CONFIG_NFS_V4_1)
 114 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 115 {
 116         /*
 117          * Create an svc_sock for the back channel service that shares the
 118          * fore channel connection.
 119          * Returns the input port (0) and sets the svc_serv bc_xprt on success
 120          */
 121         return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
 122                               SVC_SOCK_ANONYMOUS);
 123 }
 124
 125 /*
 126  * The callback service for NFSv4.1 callbacks
 127  */
 128 static int
 129 nfs41_callback_svc(void *vrqstp)
 130 {
 131         struct svc_rqst *rqstp = vrqstp;
 132         struct svc_serv *serv = rqstp->rq_server;
 133         struct rpc_rqst *req;
 134         int error;
 135         DEFINE_WAIT(wq);
 136
 137         set_freezable();
 138
 139         while (!kthread_should_stop()) {
 140                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 141                 spin_lock_bh(&serv->sv_cb_lock);
 142                 if (!list_empty(&serv->sv_cb_list)) {
 143                         req = list_first_entry(&serv->sv_cb_list,
 144                                         struct rpc_rqst, rq_bc_list);
 145                         list_del(&req->rq_bc_list);
 146                         spin_unlock_bh(&serv->sv_cb_lock);
 147                         dprintk("Invoking bc_svc_process()\n");
 148                         error = bc_svc_process(serv, req, rqstp);
 149                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 150                                 error);
 151                 } else {
 152                         spin_unlock_bh(&serv->sv_cb_lock);
 153                         schedule();
 154                 }
 155                 finish_wait(&serv->sv_cb_waitq, &wq);
 156         }
 157         return 0;
 158 }
 159
 160 /*
 161  * Bring up the NFSv4.1 callback service
 162  */
 163 static struct svc_rqst *
 164 nfs41_callback_up(struct svc_serv *serv)
 165 {
 166         struct svc_rqst *rqstp;
 167
 168         INIT_LIST_HEAD(&serv->sv_cb_list);
 169         spin_lock_init(&serv->sv_cb_lock);
 170         init_waitqueue_head(&serv->sv_cb_waitq);
 171         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 172         if (IS_ERR(rqstp)) {
 173                 svc_xprt_put(serv->sv_bc_xprt);
 174                 serv->sv_bc_xprt = NULL;
 175         }
 176         dprintk("--> %s return %ld\n", __func__,
 177                 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
 178         return rqstp;
 179 }
 180
 181 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 182                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 183 {
 184         *rqstpp = nfs41_callback_up(serv);
 185         *callback_svc = nfs41_callback_svc;
 186 }
 187
 188 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 189                 struct svc_serv *serv)
 190 {
 191         if (minorversion)
 192                 /*
 193                  * Save the svc_serv in the transport so that it can
 194                  * be referenced when the session backchannel is initialized
 195                  */
 196                 xprt->bc_serv = serv;
 197 }
 198 #else
 199 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 200 {
 201         return 0;
 202 }
 203
 204 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 205                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 206 {
 207         *rqstpp = ERR_PTR(-ENOTSUPP);
 208         *callback_svc = ERR_PTR(-ENOTSUPP);
 209 }
 210
 211 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 212                 struct svc_serv *serv)
 213 {
 214 }
 215 #endif /* CONFIG_NFS_V4_1 */
 216
 217 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 218                                   struct svc_serv *serv)
 219 {
 220         struct svc_rqst *rqstp;
 221         int (*callback_svc)(void *vrqstp);
 222         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 223         char svc_name[12];
 224         int ret;
 225
 226         nfs_callback_bc_serv(minorversion, xprt, serv);
 227
 228         if (cb_info->task)
 229                 return 0;
 230
 231         switch (minorversion) {
 232         case 0:
 233                 /* v4.0 callback setup */
 234                 rqstp = nfs4_callback_up(serv);
 235                 callback_svc = nfs4_callback_svc;
 236                 break;
 237         default:
 238                 nfs_minorversion_callback_svc_setup(serv,
 239                                 &rqstp, &callback_svc);
 240         }
 241
 242         if (IS_ERR(rqstp))
 243                 return PTR_ERR(rqstp);
 244
 245         svc_sock_update_bufs(serv);
 246
 247         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 248         cb_info->serv = serv;
 249         cb_info->rqst = rqstp;
 250         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 251         if (IS_ERR(cb_info->task)) {
 252                 ret = PTR_ERR(cb_info->task);
 253                 svc_exit_thread(cb_info->rqst);
 254                 cb_info->rqst = NULL;
 255                 cb_info->task = NULL;
 256                 return PTR_ERR(cb_info->task);
 257         }
 258         dprintk("nfs_callback_up: service started\n");
 259         return 0;
 260 }
 261
 262 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
 263 {
 264         struct nfs_net *nn = net_generic(net, nfs_net_id);
 265
 266         if (--nn->cb_users[minorversion])
 267                 return;
 268
 269         dprintk("NFS: destroy per-net callback data; net=%p\n", net);
 270         svc_shutdown_net(serv, net);
 271 }
 272
 273 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 274 {
 275         struct nfs_net *nn = net_generic(net, nfs_net_id);
 276         int ret;
 277
 278         if (nn->cb_users[minorversion]++)
 279                 return 0;
 280
 281         dprintk("NFS: create per-net callback data; net=%p\n", net);
 282
 283         ret = svc_bind(serv, net);
 284         if (ret < 0) {
 285                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 286                 goto err_bind;
 287         }
 288
 289         switch (minorversion) {
 290                 case 0:
 291                         ret = nfs4_callback_up_net(serv, net);
 292                         break;
 293                 case 1:
 294                         ret = nfs41_callback_up_net(serv, net);
 295                         break;
 296                 default:
 297                         printk(KERN_ERR "NFS: unknown callback version: %d\n",
 298                                         minorversion);
 299                         ret = -EINVAL;
 300                         break;
 301         }
 302
 303         if (ret < 0) {
 304                 printk(KERN_ERR "NFS: callback service start failed\n");
 305                 goto err_socks;
 306         }
 307         return 0;
 308
 309 err_socks:
 310         svc_rpcb_cleanup(serv, net);
 311 err_bind:
 312         dprintk("NFS: Couldn't create callback socket: err = %d; "
 313                         "net = %p\n", ret, net);
 314         return ret;
 315 }
 316
 317 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 318 {
 319         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 320         struct svc_serv *serv;
 321
 322         /*
 323          * Check whether we're already up and running.
 324          */
 325         if (cb_info->task) {
 326                 /*
 327                  * Note: increase service usage, because later in case of error
 328                  * svc_destroy() will be called.
 329                  */
 330                 svc_get(cb_info->serv);
 331                 return cb_info->serv;
 332         }
 333
 334         /*
 335          * Sanity check: if there's no task,
 336          * we should be the first user ...
 337          */
 338         if (cb_info->users)
 339                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 340                         cb_info->users);
 341
 342         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 343         if (!serv) {
 344                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 345                 return ERR_PTR(-ENOMEM);
 346         }
 347         /* As there is only one thread we need to over-ride the
 348          * default maximum of 80 connections
 349          */
 350         serv->sv_maxconn = 1024;
 351         dprintk("nfs_callback_create_svc: service created\n");
 352         return serv;
 353 }
 354
 355 /*
 356  * Bring up the callback thread if it is not already up.
 357  */
 358 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 359 {
 360         struct svc_serv *serv;
 361         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 362         int ret;
 363         struct net *net = xprt->xprt_net;
 364
 365         mutex_lock(&nfs_callback_mutex);
 366
 367         serv = nfs_callback_create_svc(minorversion);
 368         if (IS_ERR(serv)) {
 369                 ret = PTR_ERR(serv);
 370                 goto err_create;
 371         }
 372
 373         ret = nfs_callback_up_net(minorversion, serv, net);
 374         if (ret < 0)
 375                 goto err_net;
 376
 377         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 378         if (ret < 0)
 379                 goto err_start;
 380
 381         cb_info->users++;
 382         /*
 383          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 384          * svc_prepare_thread increments that. So we need to call svc_destroy
 385          * on both success and failure so that the refcount is 1 when the
 386          * thread exits.
 387          */
 388 err_net:
 389         svc_destroy(serv);
 390 err_create:
 391         mutex_unlock(&nfs_callback_mutex);
 392         return ret;
 393
 394 err_start:
 395         nfs_callback_down_net(minorversion, serv, net);
 396         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 397         goto err_net;
 398 }
 399
 400 /*
 401  * Kill the callback thread if it's no longer being used.
 402  */
 403 void nfs_callback_down(int minorversion, struct net *net)
 404 {
 405         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 406
 407         mutex_lock(&nfs_callback_mutex);
 408         nfs_callback_down_net(minorversion, cb_info->serv, net);
 409         cb_info->users--;
 410         if (cb_info->users == 0 && cb_info->task != NULL) {
 411                 kthread_stop(cb_info->task);
 412                 dprintk("nfs_callback_down: service stopped\n");
 413                 svc_exit_thread(cb_info->rqst);
 414                 dprintk("nfs_callback_down: service destroyed\n");
 415                 cb_info->serv = NULL;
 416                 cb_info->rqst = NULL;
 417                 cb_info->task = NULL;
 418         }
 419         mutex_unlock(&nfs_callback_mutex);
 420 }
 421
 422 /* Boolean check of RPC_AUTH_GSS principal */
 423 int
 424 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 425 {
 426         char *p = rqstp->rq_cred.cr_principal;
 427
 428         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 429                 return 1;
 430
 431         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 432         if (clp->cl_minorversion != 0)
 433                 return 0;
 434         /*
 435          * It might just be a normal user principal, in which case
 436          * userspace won't bother to tell us the name at all.
 437          */
 438         if (p == NULL)
 439                 return 0;
 440
 441         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 442
 443         if (memcmp(p, "nfs@", 4) != 0)
 444                 return 0;
 445         p += 4;
 446         if (strcmp(p, clp->cl_hostname) != 0)
 447                 return 0;
 448         return 1;
 449 }
 450
 451 /*
 452  * pg_authenticate method for nfsv4 callback threads.
 453  *
 454  * The authflavor has been negotiated, so an incorrect flavor is a server
 455  * bug. Drop packets with incorrect authflavor.
 456  *
 457  * All other checking done after NFS decoding where the nfs_client can be
 458  * found in nfs4_callback_compound
 459  */
 460 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 461 {
 462         switch (rqstp->rq_authop->flavour) {
 463         case RPC_AUTH_NULL:
 464                 if (rqstp->rq_proc != CB_NULL)
 465                         return SVC_DROP;
 466                 break;
 467         case RPC_AUTH_GSS:
 468                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 469                  if (svc_is_backchannel(rqstp))
 470                         return SVC_DROP;
 471         }
 472         return SVC_OK;
 473 }
 474
 475 /*
 476  * Define NFS4 callback program
 477  */
 478 static struct svc_version *nfs4_callback_version[] = {
 479         [1] = &nfs4_callback_version1,
 480         [4] = &nfs4_callback_version4,
 481 };
 482
 483 static struct svc_stat nfs4_callback_stats;
 484
 485 static struct svc_program nfs4_callback_program = {
 486         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 487         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 488         .pg_vers = nfs4_callback_version,               /* version table */
 489         .pg_name = "NFSv4 callback",                    /* service name */
 490         .pg_class = "nfs",                              /* authentication class */
 491         .pg_stats = &nfs4_callback_stats,
 492         .pg_authenticate = nfs_callback_authenticate,
 493 };