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