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         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 int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 264 {
 265         int ret;
 266
 267         dprintk("NFS: create per-net callback data; net=%p\n", net);
 268
 269         ret = svc_bind(serv, net);
 270         if (ret < 0) {
 271                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 272                 goto err_bind;
 273         }
 274
 275         switch (minorversion) {
 276                 case 0:
 277                         ret = nfs4_callback_up_net(serv, net);
 278                         break;
 279                 case 1:
 280                         ret = nfs41_callback_up_net(serv, net);
 281                         break;
 282                 default:
 283                         printk(KERN_ERR "NFS: unknown callback version: %d\n",
 284                                         minorversion);
 285                         ret = -EINVAL;
 286                         break;
 287         }
 288
 289         if (ret < 0) {
 290                 printk(KERN_ERR "NFS: callback service start failed\n");
 291                 goto err_socks;
 292         }
 293         return 0;
 294
 295 err_socks:
 296         svc_rpcb_cleanup(serv, net);
 297 err_bind:
 298         dprintk("NFS: Couldn't create callback socket: err = %d; "
 299                         "net = %p\n", ret, net);
 300         return ret;
 301 }
 302
 303 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 304 {
 305         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 306         struct svc_serv *serv;
 307
 308         /*
 309          * Check whether we're already up and running.
 310          */
 311         if (cb_info->task) {
 312                 /*
 313                  * Note: increase service usage, because later in case of error
 314                  * svc_destroy() will be called.
 315                  */
 316                 svc_get(cb_info->serv);
 317                 return cb_info->serv;
 318         }
 319
 320         /*
 321          * Sanity check: if there's no task,
 322          * we should be the first user ...
 323          */
 324         if (cb_info->users)
 325                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 326                         cb_info->users);
 327
 328         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 329         if (!serv) {
 330                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 331                 return ERR_PTR(-ENOMEM);
 332         }
 333         /* As there is only one thread we need to over-ride the
 334          * default maximum of 80 connections
 335          */
 336         serv->sv_maxconn = 1024;
 337         dprintk("nfs_callback_create_svc: service created\n");
 338         return serv;
 339 }
 340
 341 /*
 342  * Bring up the callback thread if it is not already up.
 343  */
 344 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 345 {
 346         struct svc_serv *serv;
 347         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 348         int ret;
 349         struct net *net = xprt->xprt_net;
 350
 351         mutex_lock(&nfs_callback_mutex);
 352
 353         serv = nfs_callback_create_svc(minorversion);
 354         if (IS_ERR(serv)) {
 355                 ret = PTR_ERR(serv);
 356                 goto err_create;
 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         cb_info->users++;
 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 err_net:
 375         svc_destroy(serv);
 376 err_create:
 377         mutex_unlock(&nfs_callback_mutex);
 378         return ret;
 379
 380 err_start:
 381         svc_shutdown_net(serv, net);
 382         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 383         goto err_net;
 384 }
 385
 386 /*
 387  * Kill the callback thread if it's no longer being used.
 388  */
 389 void nfs_callback_down(int minorversion, struct net *net)
 390 {
 391         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 392
 393         mutex_lock(&nfs_callback_mutex);
 394         cb_info->users--;
 395         if (cb_info->users == 0 && cb_info->task != NULL) {
 396                 kthread_stop(cb_info->task);
 397                 svc_shutdown_net(cb_info->serv, net);
 398                 svc_exit_thread(cb_info->rqst);
 399                 cb_info->serv = NULL;
 400                 cb_info->rqst = NULL;
 401                 cb_info->task = NULL;
 402         }
 403         mutex_unlock(&nfs_callback_mutex);
 404 }
 405
 406 /* Boolean check of RPC_AUTH_GSS principal */
 407 int
 408 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 409 {
 410         char *p = rqstp->rq_cred.cr_principal;
 411
 412         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 413                 return 1;
 414
 415         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 416         if (clp->cl_minorversion != 0)
 417                 return 0;
 418         /*
 419          * It might just be a normal user principal, in which case
 420          * userspace won't bother to tell us the name at all.
 421          */
 422         if (p == NULL)
 423                 return 0;
 424
 425         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 426
 427         if (memcmp(p, "nfs@", 4) != 0)
 428                 return 0;
 429         p += 4;
 430         if (strcmp(p, clp->cl_hostname) != 0)
 431                 return 0;
 432         return 1;
 433 }
 434
 435 /*
 436  * pg_authenticate method for nfsv4 callback threads.
 437  *
 438  * The authflavor has been negotiated, so an incorrect flavor is a server
 439  * bug. Drop packets with incorrect authflavor.
 440  *
 441  * All other checking done after NFS decoding where the nfs_client can be
 442  * found in nfs4_callback_compound
 443  */
 444 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 445 {
 446         switch (rqstp->rq_authop->flavour) {
 447         case RPC_AUTH_NULL:
 448                 if (rqstp->rq_proc != CB_NULL)
 449                         return SVC_DROP;
 450                 break;
 451         case RPC_AUTH_GSS:
 452                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 453                  if (svc_is_backchannel(rqstp))
 454                         return SVC_DROP;
 455         }
 456         return SVC_OK;
 457 }
 458
 459 /*
 460  * Define NFS4 callback program
 461  */
 462 static struct svc_version *nfs4_callback_version[] = {
 463         [1] = &nfs4_callback_version1,
 464         [4] = &nfs4_callback_version4,
 465 };
 466
 467 static struct svc_stat nfs4_callback_stats;
 468
 469 static struct svc_program nfs4_callback_program = {
 470         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 471         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 472         .pg_vers = nfs4_callback_version,               /* version table */
 473         .pg_name = "NFSv4 callback",                    /* service name */
 474         .pg_class = "nfs",                              /* authentication class */
 475         .pg_stats = &nfs4_callback_stats,
 476         .pg_authenticate = nfs_callback_authenticate,
 477 };