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 unsigned short nfs_callback_tcpport6;
  42
  43 static int nfs4_callback_up_net(struct svc_serv *serv, struct net *net)
  44 {
  45         int ret;
  46         struct nfs_net *nn = net_generic(net, nfs_net_id);
  47
  48         ret = svc_create_xprt(serv, "tcp", net, PF_INET,
  49                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  50         if (ret <= 0)
  51                 goto out_err;
  52         nn->nfs_callback_tcpport = ret;
  53         dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  54                         nn->nfs_callback_tcpport, PF_INET, net);
  55
  56         ret = svc_create_xprt(serv, "tcp", net, PF_INET6,
  57                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
  58         if (ret > 0) {
  59                 nfs_callback_tcpport6 = ret;
  60                 dprintk("NFS: Callback listener port = %u (af %u, net %p)\n",
  61                                 nfs_callback_tcpport6, PF_INET6, net);
  62         } else if (ret != -EAFNOSUPPORT)
  63                 goto out_err;
  64         return 0;
  65
  66 out_err:
  67         return (ret) ? ret : -ENOMEM;
  68 }
  69
  70 /*
  71  * This is the NFSv4 callback kernel thread.
  72  */
  73 static int
  74 nfs4_callback_svc(void *vrqstp)
  75 {
  76         int err, preverr = 0;
  77         struct svc_rqst *rqstp = vrqstp;
  78
  79         set_freezable();
  80
  81         while (!kthread_should_stop()) {
  82                 /*
  83                  * Listen for a request on the socket
  84                  */
  85                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  86                 if (err == -EAGAIN || err == -EINTR) {
  87                         preverr = err;
  88                         continue;
  89                 }
  90                 if (err < 0) {
  91                         if (err != preverr) {
  92                                 printk(KERN_WARNING "NFS: %s: unexpected error "
  93                                         "from svc_recv (%d)\n", __func__, err);
  94                                 preverr = err;
  95                         }
  96                         schedule_timeout_uninterruptible(HZ);
  97                         continue;
  98                 }
  99                 preverr = err;
 100                 svc_process(rqstp);
 101         }
 102         return 0;
 103 }
 104
 105 /*
 106  * Prepare to bring up the NFSv4 callback service
 107  */
 108 static struct svc_rqst *
 109 nfs4_callback_up(struct svc_serv *serv)
 110 {
 111         return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 112 }
 113
 114 #if defined(CONFIG_NFS_V4_1)
 115 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 116 {
 117         /*
 118          * Create an svc_sock for the back channel service that shares the
 119          * fore channel connection.
 120          * Returns the input port (0) and sets the svc_serv bc_xprt on success
 121          */
 122         return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
 123                               SVC_SOCK_ANONYMOUS);
 124 }
 125
 126 /*
 127  * The callback service for NFSv4.1 callbacks
 128  */
 129 static int
 130 nfs41_callback_svc(void *vrqstp)
 131 {
 132         struct svc_rqst *rqstp = vrqstp;
 133         struct svc_serv *serv = rqstp->rq_server;
 134         struct rpc_rqst *req;
 135         int error;
 136         DEFINE_WAIT(wq);
 137
 138         set_freezable();
 139
 140         while (!kthread_should_stop()) {
 141                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 142                 spin_lock_bh(&serv->sv_cb_lock);
 143                 if (!list_empty(&serv->sv_cb_list)) {
 144                         req = list_first_entry(&serv->sv_cb_list,
 145                                         struct rpc_rqst, rq_bc_list);
 146                         list_del(&req->rq_bc_list);
 147                         spin_unlock_bh(&serv->sv_cb_lock);
 148                         dprintk("Invoking bc_svc_process()\n");
 149                         error = bc_svc_process(serv, req, rqstp);
 150                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 151                                 error);
 152                 } else {
 153                         spin_unlock_bh(&serv->sv_cb_lock);
 154                         schedule();
 155                 }
 156                 finish_wait(&serv->sv_cb_waitq, &wq);
 157         }
 158         return 0;
 159 }
 160
 161 /*
 162  * Bring up the NFSv4.1 callback service
 163  */
 164 static struct svc_rqst *
 165 nfs41_callback_up(struct svc_serv *serv)
 166 {
 167         struct svc_rqst *rqstp;
 168
 169         INIT_LIST_HEAD(&serv->sv_cb_list);
 170         spin_lock_init(&serv->sv_cb_lock);
 171         init_waitqueue_head(&serv->sv_cb_waitq);
 172         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 173         if (IS_ERR(rqstp)) {
 174                 svc_xprt_put(serv->sv_bc_xprt);
 175                 serv->sv_bc_xprt = NULL;
 176         }
 177         dprintk("--> %s return %ld\n", __func__,
 178                 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
 179         return rqstp;
 180 }
 181
 182 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 183                 struct svc_serv *serv,
 184                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 185 {
 186         if (minorversion) {
 187                 *rqstpp = nfs41_callback_up(serv);
 188                 *callback_svc = nfs41_callback_svc;
 189         }
 190         return minorversion;
 191 }
 192
 193 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 194                 struct svc_serv *serv)
 195 {
 196         if (minorversion)
 197                 /*
 198                  * Save the svc_serv in the transport so that it can
 199                  * be referenced when the session backchannel is initialized
 200                  */
 201                 xprt->bc_serv = serv;
 202 }
 203 #else
 204 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 205 {
 206         return 0;
 207 }
 208
 209 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 210                 struct svc_serv *serv,
 211                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 212 {
 213         return 0;
 214 }
 215
 216 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 217                 struct svc_serv *serv)
 218 {
 219 }
 220 #endif /* CONFIG_NFS_V4_1 */
 221
 222 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 223                                   struct svc_serv *serv)
 224 {
 225         struct svc_rqst *rqstp;
 226         int (*callback_svc)(void *vrqstp);
 227         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 228         char svc_name[12];
 229         int ret;
 230         int minorversion_setup;
 231
 232         nfs_callback_bc_serv(minorversion, xprt, serv);
 233
 234         if (cb_info->task)
 235                 return 0;
 236
 237         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
 238                                         serv, &rqstp, &callback_svc);
 239         if (!minorversion_setup) {
 240                 /* v4.0 callback setup */
 241                 rqstp = nfs4_callback_up(serv);
 242                 callback_svc = nfs4_callback_svc;
 243         }
 244
 245         if (IS_ERR(rqstp))
 246                 return PTR_ERR(rqstp);
 247
 248         svc_sock_update_bufs(serv);
 249
 250         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 251         cb_info->serv = serv;
 252         cb_info->rqst = rqstp;
 253         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 254         if (IS_ERR(cb_info->task)) {
 255                 ret = PTR_ERR(cb_info->task);
 256                 svc_exit_thread(cb_info->rqst);
 257                 cb_info->rqst = NULL;
 258                 cb_info->task = NULL;
 259                 return PTR_ERR(cb_info->task);
 260         }
 261         dprintk("nfs_callback_up: service started\n");
 262         return 0;
 263 }
 264
 265 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 266 {
 267         int ret;
 268
 269         dprintk("NFS: create per-net callback data; net=%p\n", net);
 270
 271         ret = svc_bind(serv, net);
 272         if (ret < 0) {
 273                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 274                 goto err_bind;
 275         }
 276
 277         switch (minorversion) {
 278                 case 0:
 279                         ret = nfs4_callback_up_net(serv, net);
 280                         break;
 281                 case 1:
 282                         ret = nfs41_callback_up_net(serv, net);
 283                         break;
 284                 default:
 285                         printk(KERN_ERR "NFS: unknown callback version: %d\n",
 286                                         minorversion);
 287                         ret = -EINVAL;
 288                         break;
 289         }
 290
 291         if (ret < 0) {
 292                 printk(KERN_ERR "NFS: callback service start failed\n");
 293                 goto err_socks;
 294         }
 295         return 0;
 296
 297 err_socks:
 298         svc_rpcb_cleanup(serv, net);
 299 err_bind:
 300         dprintk("NFS: Couldn't create callback socket: err = %d; "
 301                         "net = %p\n", ret, net);
 302         return ret;
 303 }
 304
 305 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 306 {
 307         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 308         struct svc_serv *serv;
 309
 310         /*
 311          * Check whether we're already up and running.
 312          */
 313         if (cb_info->task) {
 314                 /*
 315                  * Note: increase service usage, because later in case of error
 316                  * svc_destroy() will be called.
 317                  */
 318                 svc_get(cb_info->serv);
 319                 return cb_info->serv;
 320         }
 321
 322         /*
 323          * Sanity check: if there's no task,
 324          * we should be the first user ...
 325          */
 326         if (cb_info->users)
 327                 printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 328                         cb_info->users);
 329
 330         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 331         if (!serv) {
 332                 printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 333                 return ERR_PTR(-ENOMEM);
 334         }
 335         /* As there is only one thread we need to over-ride the
 336          * default maximum of 80 connections
 337          */
 338         serv->sv_maxconn = 1024;
 339         dprintk("nfs_callback_create_svc: service created\n");
 340         return serv;
 341 }
 342
 343 /*
 344  * Bring up the callback thread if it is not already up.
 345  */
 346 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 347 {
 348         struct svc_serv *serv;
 349         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 350         int ret;
 351         struct net *net = xprt->xprt_net;
 352
 353         mutex_lock(&nfs_callback_mutex);
 354
 355         serv = nfs_callback_create_svc(minorversion);
 356         if (IS_ERR(serv)) {
 357                 ret = PTR_ERR(serv);
 358                 goto err_create;
 359         }
 360
 361         ret = nfs_callback_up_net(minorversion, serv, net);
 362         if (ret < 0)
 363                 goto err_net;
 364
 365         ret = nfs_callback_start_svc(minorversion, xprt, serv);
 366         if (ret < 0)
 367                 goto err_start;
 368
 369         cb_info->users++;
 370         /*
 371          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 372          * svc_prepare_thread increments that. So we need to call svc_destroy
 373          * on both success and failure so that the refcount is 1 when the
 374          * thread exits.
 375          */
 376 err_net:
 377         svc_destroy(serv);
 378 err_create:
 379         mutex_unlock(&nfs_callback_mutex);
 380         return ret;
 381
 382 err_start:
 383         svc_shutdown_net(serv, net);
 384         dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
 385         goto err_net;
 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 };