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
  27 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  28
  29 struct nfs_callback_data {
  30         unsigned int users;
  31         struct svc_serv *serv;
  32         struct svc_rqst *rqst;
  33         struct task_struct *task;
  34 };
  35
  36 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
  37 static DEFINE_MUTEX(nfs_callback_mutex);
  38 static struct svc_program nfs4_callback_program;
  39
  40 unsigned short nfs_callback_tcpport6;
  41
  42 static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
  43 {
  44         int ret;
  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         nfs_callback_tcpport = ret;
  51         dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  52                         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                 nfs_callback_tcpport6 = ret;
  58                 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  59                                 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         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
 233                                         serv, &rqstp, &callback_svc);
 234         if (!minorversion_setup) {
 235                 /* v4.0 callback setup */
 236                 rqstp = nfs4_callback_up(serv);
 237                 callback_svc = nfs4_callback_svc;
 238         }
 239
 240         if (IS_ERR(rqstp))
 241                 return PTR_ERR(rqstp);
 242
 243         svc_sock_update_bufs(serv);
 244
 245         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 246         cb_info->serv = serv;
 247         cb_info->rqst = rqstp;
 248         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 249         if (IS_ERR(cb_info->task)) {
 250                 ret = PTR_ERR(cb_info->task);
 251                 svc_exit_thread(cb_info->rqst);
 252                 cb_info->rqst = NULL;
 253                 cb_info->task = NULL;
 254                 return PTR_ERR(cb_info->task);
 255         }
 256         dprintk("nfs_callback_up: service started\n");
 257         return 0;
 258 }
 259
 260 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 261 {
 262         int ret;
 263
 264         dprintk("NFS: create per-net callback data; net=%p\n", net);
 265
 266         ret = svc_bind(serv, net);
 267         if (ret < 0) {
 268                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 269                 goto err_bind;
 270         }
 271
 272         switch (minorversion) {
 273                 case 0:
 274                         ret = nfs4_callback_up_net(serv, net);
 275                         break;
 276                 case 1:
 277                         ret = nfs41_callback_up_net(serv, net);
 278                         break;
 279                 default:
 280                         printk(KERN_ERR "NFS: unknown callback version: %d\n",
 281                                         minorversion);
 282                         ret = -EINVAL;
 283                         break;
 284         }
 285
 286         if (ret < 0) {
 287                 printk(KERN_ERR "NFS: callback service start failed\n");
 288                 goto err_socks;
 289         }
 290         return 0;
 291
 292 err_socks:
 293         svc_rpcb_cleanup(serv, net);
 294 err_bind:
 295         return ret;
 296 }
 297
 298 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 299 {
 300         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 301         struct svc_serv *serv;
 302
 303         /*
 304          * Check whether we're already up and running.
 305          */
 306         if (cb_info->task) {
 307                 /*
 308                  * Note: increase service usage, because later in case of error
 309                  * svc_destroy() will be called.
 310                  */
 311                 svc_get(cb_info->serv);
 312                 return cb_info->serv;
 313         }
 314
 315         /*
 316          * Sanity check: if there's no task,
 317          * we should be the first user ...
 318          */
 319         if (cb_info->users)
 320                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 321                         cb_info->users);
 322
 323         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 324         if (!serv) {
 325                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 326                 return ERR_PTR(-ENOMEM);
 327         }
 328         /* As there is only one thread we need to over-ride the
 329          * default maximum of 80 connections
 330          */
 331         serv->sv_maxconn = 1024;
 332         dprintk("nfs_callback_create_svc: service created\n");
 333         return serv;
 334 }
 335
 336 /*
 337  * Bring up the callback thread if it is not already up.
 338  */
 339 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 340 {
 341         struct svc_serv *serv;
 342         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 343         int ret = 0;
 344         struct net *net = xprt->xprt_net;
 345
 346         mutex_lock(&nfs_callback_mutex);
 347
 348         serv = nfs_callback_create_svc(minorversion);
 349         if (IS_ERR(serv)) {
 350                 ret = PTR_ERR(serv);
 351                 goto err_create;
 352         }
 353
 354         if (cb_info->users++ || cb_info->task != NULL) {
 355                 nfs_callback_bc_serv(minorversion, xprt, serv);
 356                 goto out;
 357         }
 358
 359         ret = nfs_callback_up_net(minorversion, serv, net);
 360         if (ret < 0)
 361                 goto err_net;
 362
 363         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 364         if (ret < 0)
 365                 goto err_start;
 366
 367 out:
 368         /*
 369          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 370          * svc_prepare_thread increments that. So we need to call svc_destroy
 371          * on both success and failure so that the refcount is 1 when the
 372          * thread exits.
 373          */
 374         svc_destroy(serv);
 375 err_create:
 376         mutex_unlock(&nfs_callback_mutex);
 377         return ret;
 378
 379 err_start:
 380         svc_shutdown_net(serv, net);
 381 err_net:
 382         dprintk("NFS: Couldn't create callback socket or server thread; "
 383                 "err = %d\n", ret);
 384         cb_info->users--;
 385         goto out;
 386 }
 387
 388 /*
 389  * Kill the callback thread if it's no longer being used.
 390  */
 391 void nfs_callback_down(int minorversion, struct net *net)
 392 {
 393         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 394
 395         mutex_lock(&nfs_callback_mutex);
 396         cb_info->users--;
 397         if (cb_info->users == 0 && cb_info->task != NULL) {
 398                 kthread_stop(cb_info->task);
 399                 svc_shutdown_net(cb_info->serv, net);
 400                 svc_exit_thread(cb_info->rqst);
 401                 cb_info->serv = NULL;
 402                 cb_info->rqst = NULL;
 403                 cb_info->task = NULL;
 404         }
 405         mutex_unlock(&nfs_callback_mutex);
 406 }
 407
 408 /* Boolean check of RPC_AUTH_GSS principal */
 409 int
 410 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 411 {
 412         char *p = rqstp->rq_cred.cr_principal;
 413
 414         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 415                 return 1;
 416
 417         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 418         if (clp->cl_minorversion != 0)
 419                 return 0;
 420         /*
 421          * It might just be a normal user principal, in which case
 422          * userspace won't bother to tell us the name at all.
 423          */
 424         if (p == NULL)
 425                 return 0;
 426
 427         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 428
 429         if (memcmp(p, "nfs@", 4) != 0)
 430                 return 0;
 431         p += 4;
 432         if (strcmp(p, clp->cl_hostname) != 0)
 433                 return 0;
 434         return 1;
 435 }
 436
 437 /*
 438  * pg_authenticate method for nfsv4 callback threads.
 439  *
 440  * The authflavor has been negotiated, so an incorrect flavor is a server
 441  * bug. Drop packets with incorrect authflavor.
 442  *
 443  * All other checking done after NFS decoding where the nfs_client can be
 444  * found in nfs4_callback_compound
 445  */
 446 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 447 {
 448         switch (rqstp->rq_authop->flavour) {
 449         case RPC_AUTH_NULL:
 450                 if (rqstp->rq_proc != CB_NULL)
 451                         return SVC_DROP;
 452                 break;
 453         case RPC_AUTH_GSS:
 454                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 455                  if (svc_is_backchannel(rqstp))
 456                         return SVC_DROP;
 457         }
 458         return SVC_OK;
 459 }
 460
 461 /*
 462  * Define NFS4 callback program
 463  */
 464 static struct svc_version *nfs4_callback_version[] = {
 465         [1] = &nfs4_callback_version1,
 466         [4] = &nfs4_callback_version4,
 467 };
 468
 469 static struct svc_stat nfs4_callback_stats;
 470
 471 static struct svc_program nfs4_callback_program = {
 472         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 473         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 474         .pg_vers = nfs4_callback_version,               /* version table */
 475         .pg_name = "NFSv4 callback",                    /* service name */
 476         .pg_class = "nfs",                              /* authentication class */
 477         .pg_stats = &nfs4_callback_stats,
 478         .pg_authenticate = nfs_callback_authenticate,
 479 };