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;
  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                         continue;
  87                 svc_process(rqstp);
  88         }
  89         return 0;
  90 }
  91
  92 /*
  93  * Prepare to bring up the NFSv4 callback service
  94  */
  95 static struct svc_rqst *
  96 nfs4_callback_up(struct svc_serv *serv)
  97 {
  98         return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
  99 }
 100
 101 #if defined(CONFIG_NFS_V4_1)
 102 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 103 {
 104         /*
 105          * Create an svc_sock for the back channel service that shares the
 106          * fore channel connection.
 107          * Returns the input port (0) and sets the svc_serv bc_xprt on success
 108          */
 109         return svc_create_xprt(serv, "tcp-bc", net, PF_INET, 0,
 110                               SVC_SOCK_ANONYMOUS);
 111 }
 112
 113 /*
 114  * The callback service for NFSv4.1 callbacks
 115  */
 116 static int
 117 nfs41_callback_svc(void *vrqstp)
 118 {
 119         struct svc_rqst *rqstp = vrqstp;
 120         struct svc_serv *serv = rqstp->rq_server;
 121         struct rpc_rqst *req;
 122         int error;
 123         DEFINE_WAIT(wq);
 124
 125         set_freezable();
 126
 127         while (!kthread_should_stop()) {
 128                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 129                 spin_lock_bh(&serv->sv_cb_lock);
 130                 if (!list_empty(&serv->sv_cb_list)) {
 131                         req = list_first_entry(&serv->sv_cb_list,
 132                                         struct rpc_rqst, rq_bc_list);
 133                         list_del(&req->rq_bc_list);
 134                         spin_unlock_bh(&serv->sv_cb_lock);
 135                         dprintk("Invoking bc_svc_process()\n");
 136                         error = bc_svc_process(serv, req, rqstp);
 137                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 138                                 error);
 139                 } else {
 140                         spin_unlock_bh(&serv->sv_cb_lock);
 141                         schedule();
 142                 }
 143                 finish_wait(&serv->sv_cb_waitq, &wq);
 144         }
 145         return 0;
 146 }
 147
 148 /*
 149  * Bring up the NFSv4.1 callback service
 150  */
 151 static struct svc_rqst *
 152 nfs41_callback_up(struct svc_serv *serv)
 153 {
 154         struct svc_rqst *rqstp;
 155
 156         INIT_LIST_HEAD(&serv->sv_cb_list);
 157         spin_lock_init(&serv->sv_cb_lock);
 158         init_waitqueue_head(&serv->sv_cb_waitq);
 159         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 160         if (IS_ERR(rqstp)) {
 161                 svc_xprt_put(serv->sv_bc_xprt);
 162                 serv->sv_bc_xprt = NULL;
 163         }
 164         dprintk("--> %s return %ld\n", __func__,
 165                 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
 166         return rqstp;
 167 }
 168
 169 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 170                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 171 {
 172         *rqstpp = nfs41_callback_up(serv);
 173         *callback_svc = nfs41_callback_svc;
 174 }
 175
 176 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 177                 struct svc_serv *serv)
 178 {
 179         if (minorversion)
 180                 /*
 181                  * Save the svc_serv in the transport so that it can
 182                  * be referenced when the session backchannel is initialized
 183                  */
 184                 xprt->bc_serv = serv;
 185 }
 186 #else
 187 static int nfs41_callback_up_net(struct svc_serv *serv, struct net *net)
 188 {
 189         return 0;
 190 }
 191
 192 static void nfs_minorversion_callback_svc_setup(struct svc_serv *serv,
 193                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 194 {
 195         *rqstpp = ERR_PTR(-ENOTSUPP);
 196         *callback_svc = ERR_PTR(-ENOTSUPP);
 197 }
 198
 199 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 200                 struct svc_serv *serv)
 201 {
 202 }
 203 #endif /* CONFIG_NFS_V4_1 */
 204
 205 static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
 206                                   struct svc_serv *serv)
 207 {
 208         struct svc_rqst *rqstp;
 209         int (*callback_svc)(void *vrqstp);
 210         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 211         char svc_name[12];
 212         int ret;
 213
 214         nfs_callback_bc_serv(minorversion, xprt, serv);
 215
 216         if (cb_info->task)
 217                 return 0;
 218
 219         switch (minorversion) {
 220         case 0:
 221                 /* v4.0 callback setup */
 222                 rqstp = nfs4_callback_up(serv);
 223                 callback_svc = nfs4_callback_svc;
 224                 break;
 225         default:
 226                 nfs_minorversion_callback_svc_setup(serv,
 227                                 &rqstp, &callback_svc);
 228         }
 229
 230         if (IS_ERR(rqstp))
 231                 return PTR_ERR(rqstp);
 232
 233         svc_sock_update_bufs(serv);
 234
 235         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 236         cb_info->serv = serv;
 237         cb_info->rqst = rqstp;
 238         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 239         if (IS_ERR(cb_info->task)) {
 240                 ret = PTR_ERR(cb_info->task);
 241                 svc_exit_thread(cb_info->rqst);
 242                 cb_info->rqst = NULL;
 243                 cb_info->task = NULL;
 244                 return ret;
 245         }
 246         dprintk("nfs_callback_up: service started\n");
 247         return 0;
 248 }
 249
 250 static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
 251 {
 252         struct nfs_net *nn = net_generic(net, nfs_net_id);
 253
 254         if (--nn->cb_users[minorversion])
 255                 return;
 256
 257         dprintk("NFS: destroy per-net callback data; net=%p\n", net);
 258         svc_shutdown_net(serv, net);
 259 }
 260
 261 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 262 {
 263         struct nfs_net *nn = net_generic(net, nfs_net_id);
 264         int ret;
 265
 266         if (nn->cb_users[minorversion]++)
 267                 return 0;
 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         nfs_callback_down_net(minorversion, 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         nfs_callback_down_net(minorversion, cb_info->serv, net);
 397         cb_info->users--;
 398         if (cb_info->users == 0 && cb_info->task != NULL) {
 399                 kthread_stop(cb_info->task);
 400                 dprintk("nfs_callback_down: service stopped\n");
 401                 svc_exit_thread(cb_info->rqst);
 402                 dprintk("nfs_callback_down: service destroyed\n");
 403                 cb_info->serv = NULL;
 404                 cb_info->rqst = NULL;
 405                 cb_info->task = NULL;
 406         }
 407         mutex_unlock(&nfs_callback_mutex);
 408 }
 409
 410 /* Boolean check of RPC_AUTH_GSS principal */
 411 int
 412 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 413 {
 414         char *p = rqstp->rq_cred.cr_principal;
 415
 416         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 417                 return 1;
 418
 419         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 420         if (clp->cl_minorversion != 0)
 421                 return 0;
 422         /*
 423          * It might just be a normal user principal, in which case
 424          * userspace won't bother to tell us the name at all.
 425          */
 426         if (p == NULL)
 427                 return 0;
 428
 429         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 430
 431         if (memcmp(p, "nfs@", 4) != 0)
 432                 return 0;
 433         p += 4;
 434         if (strcmp(p, clp->cl_hostname) != 0)
 435                 return 0;
 436         return 1;
 437 }
 438
 439 /*
 440  * pg_authenticate method for nfsv4 callback threads.
 441  *
 442  * The authflavor has been negotiated, so an incorrect flavor is a server
 443  * bug. Drop packets with incorrect authflavor.
 444  *
 445  * All other checking done after NFS decoding where the nfs_client can be
 446  * found in nfs4_callback_compound
 447  */
 448 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 449 {
 450         switch (rqstp->rq_authop->flavour) {
 451         case RPC_AUTH_NULL:
 452                 if (rqstp->rq_proc != CB_NULL)
 453                         return SVC_DROP;
 454                 break;
 455         case RPC_AUTH_GSS:
 456                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 457                  if (svc_is_backchannel(rqstp))
 458                         return SVC_DROP;
 459         }
 460         return SVC_OK;
 461 }
 462
 463 /*
 464  * Define NFS4 callback program
 465  */
 466 static struct svc_version *nfs4_callback_version[] = {
 467         [1] = &nfs4_callback_version1,
 468         [4] = &nfs4_callback_version4,
 469 };
 470
 471 static struct svc_stat nfs4_callback_stats;
 472
 473 static struct svc_program nfs4_callback_program = {
 474         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 475         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 476         .pg_vers = nfs4_callback_version,               /* version table */
 477         .pg_name = "NFSv4 callback",                    /* service name */
 478         .pg_class = "nfs",                              /* authentication class */
 479         .pg_stats = &nfs4_callback_stats,
 480         .pg_authenticate = nfs_callback_authenticate,
 481 };