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 #include <linux/nsproxy.h>
  21
  22 #include <net/inet_sock.h>
  23
  24 #include "nfs4_fs.h"
  25 #include "callback.h"
  26 #include "internal.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 int nfs_callback_set_tcpport;
  42 unsigned short nfs_callback_tcpport;
  43 unsigned short nfs_callback_tcpport6;
  44 #define NFS_CALLBACK_MAXPORTNR (65535U)
  45
  46 static int param_set_portnr(const char *val, const struct kernel_param *kp)
  47 {
  48         unsigned long num;
  49         int ret;
  50
  51         if (!val)
  52                 return -EINVAL;
  53         ret = strict_strtoul(val, 0, &num);
  54         if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR)
  55                 return -EINVAL;
  56         *((unsigned int *)kp->arg) = num;
  57         return 0;
  58 }
  59 static struct kernel_param_ops param_ops_portnr = {
  60         .set = param_set_portnr,
  61         .get = param_get_uint,
  62 };
  63 #define param_check_portnr(name, p) __param_check(name, p, unsigned int);
  64
  65 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
  66
  67 /*
  68  * This is the NFSv4 callback kernel thread.
  69  */
  70 static int
  71 nfs4_callback_svc(void *vrqstp)
  72 {
  73         int err, preverr = 0;
  74         struct svc_rqst *rqstp = vrqstp;
  75
  76         set_freezable();
  77
  78         while (!kthread_should_stop()) {
  79                 /*
  80                  * Listen for a request on the socket
  81                  */
  82                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  83                 if (err == -EAGAIN || err == -EINTR) {
  84                         preverr = err;
  85                         continue;
  86                 }
  87                 if (err < 0) {
  88                         if (err != preverr) {
  89                                 printk(KERN_WARNING "NFS: %s: unexpected error "
  90                                         "from svc_recv (%d)\n", __func__, err);
  91                                 preverr = err;
  92                         }
  93                         schedule_timeout_uninterruptible(HZ);
  94                         continue;
  95                 }
  96                 preverr = err;
  97                 svc_process(rqstp);
  98         }
  99         return 0;
 100 }
 101
 102 /*
 103  * Prepare to bring up the NFSv4 callback service
 104  */
 105 static struct svc_rqst *
 106 nfs4_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
 107 {
 108         int ret;
 109
 110         ret = svc_create_xprt(serv, "tcp", xprt->xprt_net, PF_INET,
 111                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
 112         if (ret <= 0)
 113                 goto out_err;
 114         nfs_callback_tcpport = ret;
 115         dprintk("NFS: Callback listener port = %u (af %u)\n",
 116                         nfs_callback_tcpport, PF_INET);
 117
 118         ret = svc_create_xprt(serv, "tcp", xprt->xprt_net, PF_INET6,
 119                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
 120         if (ret > 0) {
 121                 nfs_callback_tcpport6 = ret;
 122                 dprintk("NFS: Callback listener port = %u (af %u)\n",
 123                                 nfs_callback_tcpport6, PF_INET6);
 124         } else if (ret == -EAFNOSUPPORT)
 125                 ret = 0;
 126         else
 127                 goto out_err;
 128
 129         return svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 130
 131 out_err:
 132         if (ret == 0)
 133                 ret = -ENOMEM;
 134         return ERR_PTR(ret);
 135 }
 136
 137 #if defined(CONFIG_NFS_V4_1)
 138 /*
 139  * The callback service for NFSv4.1 callbacks
 140  */
 141 static int
 142 nfs41_callback_svc(void *vrqstp)
 143 {
 144         struct svc_rqst *rqstp = vrqstp;
 145         struct svc_serv *serv = rqstp->rq_server;
 146         struct rpc_rqst *req;
 147         int error;
 148         DEFINE_WAIT(wq);
 149
 150         set_freezable();
 151
 152         while (!kthread_should_stop()) {
 153                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 154                 spin_lock_bh(&serv->sv_cb_lock);
 155                 if (!list_empty(&serv->sv_cb_list)) {
 156                         req = list_first_entry(&serv->sv_cb_list,
 157                                         struct rpc_rqst, rq_bc_list);
 158                         list_del(&req->rq_bc_list);
 159                         spin_unlock_bh(&serv->sv_cb_lock);
 160                         dprintk("Invoking bc_svc_process()\n");
 161                         error = bc_svc_process(serv, req, rqstp);
 162                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 163                                 error);
 164                 } else {
 165                         spin_unlock_bh(&serv->sv_cb_lock);
 166                         schedule();
 167                 }
 168                 finish_wait(&serv->sv_cb_waitq, &wq);
 169         }
 170         return 0;
 171 }
 172
 173 /*
 174  * Bring up the NFSv4.1 callback service
 175  */
 176 static struct svc_rqst *
 177 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
 178 {
 179         struct svc_rqst *rqstp;
 180         int ret;
 181
 182         /*
 183          * Create an svc_sock for the back channel service that shares the
 184          * fore channel connection.
 185          * Returns the input port (0) and sets the svc_serv bc_xprt on success
 186          */
 187         ret = svc_create_xprt(serv, "tcp-bc", xprt->xprt_net, PF_INET, 0,
 188                               SVC_SOCK_ANONYMOUS);
 189         if (ret < 0) {
 190                 rqstp = ERR_PTR(ret);
 191                 goto out;
 192         }
 193
 194         /*
 195          * Save the svc_serv in the transport so that it can
 196          * be referenced when the session backchannel is initialized
 197          */
 198         xprt->bc_serv = serv;
 199
 200         INIT_LIST_HEAD(&serv->sv_cb_list);
 201         spin_lock_init(&serv->sv_cb_lock);
 202         init_waitqueue_head(&serv->sv_cb_waitq);
 203         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);
 204         if (IS_ERR(rqstp)) {
 205                 svc_xprt_put(serv->sv_bc_xprt);
 206                 serv->sv_bc_xprt = NULL;
 207         }
 208 out:
 209         dprintk("--> %s return %ld\n", __func__,
 210                 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
 211         return rqstp;
 212 }
 213
 214 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 215                 struct svc_serv *serv, struct rpc_xprt *xprt,
 216                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 217 {
 218         if (minorversion) {
 219                 *rqstpp = nfs41_callback_up(serv, xprt);
 220                 *callback_svc = nfs41_callback_svc;
 221         }
 222         return minorversion;
 223 }
 224
 225 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 226                 struct nfs_callback_data *cb_info)
 227 {
 228         if (minorversion)
 229                 xprt->bc_serv = cb_info->serv;
 230 }
 231 #else
 232 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 233                 struct svc_serv *serv, struct rpc_xprt *xprt,
 234                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 235 {
 236         return 0;
 237 }
 238
 239 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 240                 struct nfs_callback_data *cb_info)
 241 {
 242 }
 243 #endif /* CONFIG_NFS_V4_1 */
 244
 245 /*
 246  * Bring up the callback thread if it is not already up.
 247  */
 248 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 249 {
 250         struct svc_serv *serv = NULL;
 251         struct svc_rqst *rqstp;
 252         int (*callback_svc)(void *vrqstp);
 253         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 254         char svc_name[12];
 255         int ret = 0;
 256         int minorversion_setup;
 257         struct net *net = current->nsproxy->net_ns;
 258
 259         mutex_lock(&nfs_callback_mutex);
 260         if (cb_info->users++ || cb_info->task != NULL) {
 261                 nfs_callback_bc_serv(minorversion, xprt, cb_info);
 262                 goto out;
 263         }
 264         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 265         if (!serv) {
 266                 ret = -ENOMEM;
 267                 goto out_err;
 268         }
 269
 270         ret = svc_bind(serv, net);
 271         if (ret < 0) {
 272                 printk(KERN_WARNING "NFS: bind callback service failed\n");
 273                 goto out_err;
 274         }
 275
 276         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
 277                                         serv, xprt, &rqstp, &callback_svc);
 278         if (!minorversion_setup) {
 279                 /* v4.0 callback setup */
 280                 rqstp = nfs4_callback_up(serv, xprt);
 281                 callback_svc = nfs4_callback_svc;
 282         }
 283
 284         if (IS_ERR(rqstp)) {
 285                 ret = PTR_ERR(rqstp);
 286                 goto out_err;
 287         }
 288
 289         svc_sock_update_bufs(serv);
 290
 291         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 292         cb_info->serv = serv;
 293         cb_info->rqst = rqstp;
 294         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 295         if (IS_ERR(cb_info->task)) {
 296                 ret = PTR_ERR(cb_info->task);
 297                 svc_exit_thread(cb_info->rqst);
 298                 cb_info->rqst = NULL;
 299                 cb_info->task = NULL;
 300                 goto out_err;
 301         }
 302 out:
 303         /*
 304          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 305          * svc_prepare_thread increments that. So we need to call svc_destroy
 306          * on both success and failure so that the refcount is 1 when the
 307          * thread exits.
 308          */
 309         if (serv)
 310                 svc_destroy(serv);
 311         mutex_unlock(&nfs_callback_mutex);
 312         return ret;
 313 out_err:
 314         dprintk("NFS: Couldn't create callback socket or server thread; "
 315                 "err = %d\n", ret);
 316         cb_info->users--;
 317         if (serv)
 318                 svc_shutdown_net(serv, net);
 319         goto out;
 320 }
 321
 322 /*
 323  * Kill the callback thread if it's no longer being used.
 324  */
 325 void nfs_callback_down(int minorversion)
 326 {
 327         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 328
 329         mutex_lock(&nfs_callback_mutex);
 330         cb_info->users--;
 331         if (cb_info->users == 0 && cb_info->task != NULL) {
 332                 kthread_stop(cb_info->task);
 333                 svc_shutdown_net(cb_info->serv, current->nsproxy->net_ns);
 334                 svc_exit_thread(cb_info->rqst);
 335                 cb_info->serv = NULL;
 336                 cb_info->rqst = NULL;
 337                 cb_info->task = NULL;
 338         }
 339         mutex_unlock(&nfs_callback_mutex);
 340 }
 341
 342 /* Boolean check of RPC_AUTH_GSS principal */
 343 int
 344 check_gss_callback_principal(struct nfs_client *clp, struct svc_rqst *rqstp)
 345 {
 346         char *p = rqstp->rq_cred.cr_principal;
 347
 348         if (rqstp->rq_authop->flavour != RPC_AUTH_GSS)
 349                 return 1;
 350
 351         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 352         if (clp->cl_minorversion != 0)
 353                 return 0;
 354         /*
 355          * It might just be a normal user principal, in which case
 356          * userspace won't bother to tell us the name at all.
 357          */
 358         if (p == NULL)
 359                 return 0;
 360
 361         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 362
 363         if (memcmp(p, "nfs@", 4) != 0)
 364                 return 0;
 365         p += 4;
 366         if (strcmp(p, clp->cl_hostname) != 0)
 367                 return 0;
 368         return 1;
 369 }
 370
 371 /*
 372  * pg_authenticate method for nfsv4 callback threads.
 373  *
 374  * The authflavor has been negotiated, so an incorrect flavor is a server
 375  * bug. Drop packets with incorrect authflavor.
 376  *
 377  * All other checking done after NFS decoding where the nfs_client can be
 378  * found in nfs4_callback_compound
 379  */
 380 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 381 {
 382         switch (rqstp->rq_authop->flavour) {
 383         case RPC_AUTH_NULL:
 384                 if (rqstp->rq_proc != CB_NULL)
 385                         return SVC_DROP;
 386                 break;
 387         case RPC_AUTH_GSS:
 388                 /* No RPC_AUTH_GSS support yet in NFSv4.1 */
 389                  if (svc_is_backchannel(rqstp))
 390                         return SVC_DROP;
 391         }
 392         return SVC_OK;
 393 }
 394
 395 /*
 396  * Define NFS4 callback program
 397  */
 398 static struct svc_version *nfs4_callback_version[] = {
 399         [1] = &nfs4_callback_version1,
 400         [4] = &nfs4_callback_version4,
 401 };
 402
 403 static struct svc_stat nfs4_callback_stats;
 404
 405 static struct svc_program nfs4_callback_program = {
 406         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 407         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 408         .pg_vers = nfs4_callback_version,               /* version table */
 409         .pg_name = "NFSv4 callback",                    /* service name */
 410         .pg_class = "nfs",                              /* authentication class */
 411         .pg_stats = &nfs4_callback_stats,
 412         .pg_authenticate = nfs_callback_authenticate,
 413 };