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/mutex.h>
  16 #include <linux/freezer.h>
  17 #include <linux/kthread.h>
  18 #include <linux/sunrpc/svcauth_gss.h>
  19 #include <linux/sunrpc/bc_xprt.h>
  20
  21 #include <net/inet_sock.h>
  22
  23 #include "nfs4_fs.h"
  24 #include "callback.h"
  25 #include "internal.h"
  26 #include "netns.h"
  27
  28 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  29
  30 struct nfs_callback_data {
  31         unsigned int users;
  32         struct svc_serv *serv;
  33         struct svc_rqst *rqst;
  34         struct task_struct *task;
  35 };
  36
  37 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
  38 static DEFINE_MUTEX(nfs_callback_mutex);
  39 static struct svc_program nfs4_callback_program;
  40
  41 static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
  42 {
  43         int ret;
  44         struct nfs_net *nn = net_generic(net, nfs_net_id);
  45
  46         ret = svc_create_xprt(serv, "tcp", net, PF_INET,
  47                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  48         if (ret <= 0)
  49                 goto out_err;
  50         nn->nfs_callback_tcpport = ret;
  51         dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  52                         nn->nfs_callback_tcpport, PF_INET, net);
  53
  54         ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
  55                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  56         if (ret > 0) {
  57                 nn->nfs_callback_tcpport6 = ret;
  58                 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  59                                 nn->nfs_callback_tcpport6, PF_INET6, net);
  60         } else if (ret != -EAFNOSUPPORT)
  61                 goto out_err;
  62         return 0;
  63
  64 out_err:
  65         return (ret) ? ret : -ENOMEM;
  66 }
  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 "NFS: %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 static struct svc_rqst *
 107 nfs4_callback_up(struct svc_serv *serv)
 108 {
 109         return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 110 }
 111
 112 #if defined(CONFIG_NFS_V4_1)
 113 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 114 {
 115         /*
 116          * Create an svc_sock for the back channel service that shares the
 117          * fore channel connection.
 118          * Returns the input port (0) and sets the svc_serv bc_xprt on success
 119          */
 120         return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
 121                               SVC_SOCK_ANONYMOUS);
 122 }
 123
 124 /*
 125  * The callback service for NFSv4.1 callbacks
 126  */
 127 static int
 128 nfs41_callback_svc(void *vrqstp)
 129 {
 130         struct svc_rqst *rqstp = vrqstp;
 131         struct svc_serv *serv = rqstp->rq_server;
 132         struct rpc_rqst *req;
 133         int error;
 134         DEFINE_WAIT(wq);
 135
 136         set_freezable();
 137
 138         while (!kthread_should_stop()) {
 139                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 140                 spin_lock_bh(&serv->sv_cb_lock);
 141                 if (!list_empty(&serv->sv_cb_list)) {
 142                         req = list_first_entry(&serv->sv_cb_list,
 143                                         struct rpc_rqst, rq_bc_list);
 144                         list_del(&req->rq_bc_list);
 145                         spin_unlock_bh(&serv->sv_cb_lock);
 146                         dprintk("Invoking bc_svc_process()\n");
 147                         error = bc_svc_process(serv, req, rqstp);
 148                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 149                                 error);
 150                 } else {
 151                         spin_unlock_bh(&serv->sv_cb_lock);
 152                         schedule();
 153                 }
 154                 finish_wait(&serv->sv_cb_waitq, &wq);
 155         }
 156         return 0;
 157 }
 158
 159 /*
 160  * Bring up the NFSv4.1 callback service
 161  */
 162 static struct svc_rqst *
 163 nfs41_callback_up(struct svc_serv *serv)
 164 {
 165         struct svc_rqst *rqstp;
 166
 167         INIT_LIST_HEAD(&serv->sv_cb_list);
 168         spin_lock_init(&serv->sv_cb_lock);
 169         init_waitqueue_head(&serv->sv_cb_waitq);
 170         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 171         if (IS_ERR(rqstp)) {
 172                 svc_xprt_put(serv->sv_bc_xprt);
 173                 serv->sv_bc_xprt = NULL;
 174         }
 175         dprintk("--> %s return %ld\n", __func__,
 176                 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
 177         return rqstp;
 178 }
 179
 180 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 181                 struct svc_serv *serv,
 182                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 183 {
 184         if (minorversion) {
 185                 *rqstpp = nfs41_callback_up(serv);
 186                 *callback_svc = nfs41_callback_svc;
 187         }
 188         return minorversion;
 189 }
 190
 191 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 192                 struct svc_serv *serv)
 193 {
 194         if (minorversion)
 195                 /*
 196                  * Save the svc_serv in the transport so that it can
 197                  * be referenced when the session backchannel is initialized
 198                  */
 199                 xprt->bc_serv = serv;
 200 }
 201 #else
 202 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 203 {
 204         return 0;
 205 }
 206
 207 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 208                 struct svc_serv *serv,
 209                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 210 {
 211         return 0;
 212 }
 213
 214 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 215                 struct svc_serv *serv)
 216 {
 217 }
 218 #endif /* CONFIG_NFS_V4_1 */
 219
 220 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 221                                   struct svc_serv *serv)
 222 {
 223         struct svc_rqst *rqstp;
 224         int (*callback_svc)(void *vrqstp);
 225         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 226         char svc_name[12];
 227         int ret;
 228         int minorversion_setup;
 229
 230         nfs_callback_bc_serv(minorversion, xprt, serv);
 231
 232         if (cb_info->task)
 233                 return 0;
 234
 235         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
 236                                         serv, &rqstp, &callback_svc);
 237         if (!minorversion_setup) {
 238                 /* v4.0 callback setup */
 239                 rqstp = nfs4_callback_up(serv);
 240                 callback_svc = nfs4_callback_svc;
 241         }
 242
 243         if (IS_ERR(rqstp))
 244                 return PTR_ERR(rqstp);
 245
 246         svc_sock_update_bufs(serv);
 247
 248         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 249         cb_info->serv = serv;
 250         cb_info->rqst = rqstp;
 251         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 252         if (IS_ERR(cb_info->task)) {
 253                 ret = PTR_ERR(cb_info->task);
 254                 svc_exit_thread(cb_info->rqst);
 255                 cb_info->rqst = NULL;
 256                 cb_info->task = NULL;
 257                 return PTR_ERR(cb_info->task);
 258         }
 259         dprintk("nfs_callback_up: service started\n");
 260         return 0;
 261 }
 262
 263 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
 264 {
 265         struct nfs_net *nn = net_generic(net, nfs_net_id);
 266
 267         if (--nn->cb_users[minorversion])
 268                 return;
 269
 270         dprintk("NFS: destroy per-net callback data; net=%p\n", net);
 271         svc_shutdown_net(serv, net);
 272 }
 273
 274 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 275 {
 276         struct nfs_net *nn = net_generic(net, nfs_net_id);
 277         int ret;
 278
 279         if (nn->cb_users[minorversion]++)
 280                 return 0;
 281
 282         dprintk("NFS: create per-net callback data; net=%p\n", net);
 283
 284         ret = svc_bind(serv, net);
 285         if (ret < 0) {
 286                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 287                 goto err_bind;
 288         }
 289
 290         switch (minorversion) {
 291                 case 0:
 292                         ret = nfs4_callback_up_net(serv, net);
 293                         break;
 294                 case 1:
 295                         ret = nfs41_callback_up_net(serv, net);
 296                         break;
 297                 default:
 298                         printk(KERN_ERR "NFS: unknown callback version: %d\n",
 299                                         minorversion);
 300                         ret = -EINVAL;
 301                         break;
 302         }
 303
 304         if (ret < 0) {
 305                 printk(KERN_ERR "NFS: callback service start failed\n");
 306                 goto err_socks;
 307         }
 308         return 0;
 309
 310 err_socks:
 311         svc_rpcb_cleanup(serv, net);
 312 err_bind:
 313         dprintk("NFS: Couldn't create callback socket: err = %d; "
 314                         "net = %p\n", ret, net);
 315         return ret;
 316 }
 317
 318 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 319 {
 320         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 321         struct svc_serv *serv;
 322
 323         /*
 324          * Check whether we're already up and running.
 325          */
 326         if (cb_info->task) {
 327                 /*
 328                  * Note: increase service usage, because later in case of error
 329                  * svc_destroy() will be called.
 330                  */
 331                 svc_get(cb_info->serv);
 332                 return cb_info->serv;
 333         }
 334
 335         /*
 336          * Sanity check: if there's no task,
 337          * we should be the first user ...
 338          */
 339         if (cb_info->users)
 340                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 341                         cb_info->users);
 342
 343         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 344         if (!serv) {
 345                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 346                 return ERR_PTR(-ENOMEM);
 347         }
 348         /* As there is only one thread we need to over-ride the
 349          * default maximum of 80 connections
 350          */
 351         serv->sv_maxconn = 1024;
 352         dprintk("nfs_callback_create_svc: service created\n");
 353         return serv;
 354 }
 355
 356 /*
 357  * Bring up the callback thread if it is not already up.
 358  */
 359 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 360 {
 361         struct svc_serv *serv;
 362         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 363         int ret;
 364         struct net *net = xprt->xprt_net;
 365
 366         mutex_lock(&nfs_callback_mutex);
 367
 368         serv = nfs_callback_create_svc(minorversion);
 369         if (IS_ERR(serv)) {
 370                 ret = PTR_ERR(serv);
 371                 goto err_create;
 372         }
 373
 374         ret = nfs_callback_up_net(minorversion, serv, net);
 375         if (ret < 0)
 376                 goto err_net;
 377
 378         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 379         if (ret < 0)
 380                 goto err_start;
 381
 382         cb_info->users++;
 383         /*
 384          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 385          * svc_prepare_thread increments that. So we need to call svc_destroy
 386          * on both success and failure so that the refcount is 1 when the
 387          * thread exits.
 388          */
 389 err_net:
 390         svc_destroy(serv);
 391 err_create:
 392         mutex_unlock(&nfs_callback_mutex);
 393         return ret;
 394
 395 err_start:
 396         nfs_callback_down_net(minorversion, serv, net);
 397         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 398         goto err_net;
 399 }
 400
 401 /*
 402  * Kill the callback thread if it's no longer being used.
 403  */
 404 void nfs_callback_down(int minorversion, struct net *net)
 405 {
 406         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 407
 408         mutex_lock(&nfs_callback_mutex);
 409         nfs_callback_down_net(minorversion, cb_info->serv, net);
 410         cb_info->users--;
 411         if (cb_info->users == 0 && cb_info->task != NULL) {
 412                 kthread_stop(cb_info->task);
 413                 dprintk("nfs_callback_down: service stopped\n");
 414                 svc_exit_thread(cb_info->rqst);
 415                 dprintk("nfs_callback_down: service destroyed\n");
 416                 cb_info->serv = NULL;
 417                 cb_info->rqst = NULL;
 418                 cb_info->task = NULL;
 419         }
 420         mutex_unlock(&nfs_callback_mutex);
 421 }
 422
 423 /* Boolean check of RPC_AUTH_GSS principal */
 424 int
 425 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 426 {
 427         char *p = rqstp->rq_cred.cr_principal;
 428
 429         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 430                 return 1;
 431
 432         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 433         if (clp->cl_minorversion != 0)
 434                 return 0;
 435         /*
 436          * It might just be a normal user principal, in which case
 437          * userspace won't bother to tell us the name at all.
 438          */
 439         if (p == NULL)
 440                 return 0;
 441
 442         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 443
 444         if (memcmp(p, "nfs@", 4) != 0)
 445                 return 0;
 446         p += 4;
 447         if (strcmp(p, clp->cl_hostname) != 0)
 448                 return 0;
 449         return 1;
 450 }
 451
 452 /*
 453  * pg_authenticate method for nfsv4 callback threads.
 454  *
 455  * The authflavor has been negotiated, so an incorrect flavor is a server
 456  * bug. Drop packets with incorrect authflavor.
 457  *
 458  * All other checking done after NFS decoding where the nfs_client can be
 459  * found in nfs4_callback_compound
 460  */
 461 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 462 {
 463         switch (rqstp->rq_authop->flavour) {
 464         case RPC_AUTH_NULL:
 465                 if (rqstp->rq_proc != CB_NULL)
 466                         return SVC_DROP;
 467                 break;
 468         case RPC_AUTH_GSS:
 469                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 470                  if (svc_is_backchannel(rqstp))
 471                         return SVC_DROP;
 472         }
 473         return SVC_OK;
 474 }
 475
 476 /*
 477  * Define NFS4 callback program
 478  */
 479 static struct svc_version *nfs4_callback_version[] = {
 480         [1] = &nfs4_callback_version1,
 481         [4] = &nfs4_callback_version4,
 482 };
 483
 484 static struct svc_stat nfs4_callback_stats;
 485
 486 static struct svc_program nfs4_callback_program = {
 487         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 488         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 489         .pg_vers = nfs4_callback_version,               /* version table */
 490         .pg_name = "NFSv4 callback",                    /* service name */
 491         .pg_class = "nfs",                              /* authentication class */
 492         .pg_stats = &nfs4_callback_stats,
 493         .pg_authenticate = nfs_callback_authenticate,
 494 };