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/smp_lock.h>
  13 #include <linux/sunrpc/svc.h>
  14 #include <linux/sunrpc/svcsock.h>
  15 #include <linux/nfs_fs.h>
  16 #include <linux/mutex.h>
  17 #include <linux/freezer.h>
  18 #include <linux/kthread.h>
  19 #include <linux/sunrpc/svcauth_gss.h>
  20 #if defined(CONFIG_NFS_V4_1)
  21 #include <linux/sunrpc/bc_xprt.h>
  22 #endif
  23
  24 #include <net/inet_sock.h>
  25
  26 #include "nfs4_fs.h"
  27 #include "callback.h"
  28 #include "internal.h"
  29
  30 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  31
  32 struct nfs_callback_data {
  33         unsigned int users;
  34         struct svc_serv *serv;
  35         struct svc_rqst *rqst;
  36         struct task_struct *task;
  37 };
  38
  39 static struct nfs_callback_data nfs_callback_info[NFS4_MAX_MINOR_VERSION + 1];
  40 static DEFINE_MUTEX(nfs_callback_mutex);
  41 static struct svc_program nfs4_callback_program;
  42
  43 unsigned int nfs_callback_set_tcpport;
  44 unsigned short nfs_callback_tcpport;
  45 unsigned short nfs_callback_tcpport6;
  46 #define NFS_CALLBACK_MAXPORTNR (65535U)
  47
  48 static int param_set_portnr(const char *val, struct kernel_param *kp)
  49 {
  50         unsigned long num;
  51         int ret;
  52
  53         if (!val)
  54                 return -EINVAL;
  55         ret = strict_strtoul(val, 0, &num);
  56         if (ret == -EINVAL || num > NFS_CALLBACK_MAXPORTNR)
  57                 return -EINVAL;
  58         *((unsigned int *)kp->arg) = num;
  59         return 0;
  60 }
  61
  62 static int param_get_portnr(char *buffer, struct kernel_param *kp)
  63 {
  64         return param_get_uint(buffer, kp);
  65 }
  66 #define param_check_portnr(name, p) __param_check(name, p, unsigned int);
  67
  68 module_param_named(callback_tcpport, nfs_callback_set_tcpport, portnr, 0644);
  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 "%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 struct svc_rqst *
 109 nfs4_callback_up(struct svc_serv *serv)
 110 {
 111         int ret;
 112
 113         ret = svc_create_xprt(serv, "tcp", PF_INET,
 114                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
 115         if (ret <= 0)
 116                 goto out_err;
 117         nfs_callback_tcpport = ret;
 118         dprintk("NFS: Callback listener port = %u (af %u)\n",
 119                         nfs_callback_tcpport, PF_INET);
 120
 121         ret = svc_create_xprt(serv, "tcp", PF_INET6,
 122                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
 123         if (ret > 0) {
 124                 nfs_callback_tcpport6 = ret;
 125                 dprintk("NFS: Callback listener port = %u (af %u)\n",
 126                                 nfs_callback_tcpport6, PF_INET6);
 127         } else if (ret == -EAFNOSUPPORT)
 128                 ret = 0;
 129         else
 130                 goto out_err;
 131
 132         return svc_prepare_thread(serv, &serv->sv_pools[0]);
 133
 134 out_err:
 135         if (ret == 0)
 136                 ret = -ENOMEM;
 137         return ERR_PTR(ret);
 138 }
 139
 140 #if defined(CONFIG_NFS_V4_1)
 141 /*
 142  * The callback service for NFSv4.1 callbacks
 143  */
 144 static int
 145 nfs41_callback_svc(void *vrqstp)
 146 {
 147         struct svc_rqst *rqstp = vrqstp;
 148         struct svc_serv *serv = rqstp->rq_server;
 149         struct rpc_rqst *req;
 150         int error;
 151         DEFINE_WAIT(wq);
 152
 153         set_freezable();
 154
 155         while (!kthread_should_stop()) {
 156                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 157                 spin_lock_bh(&serv->sv_cb_lock);
 158                 if (!list_empty(&serv->sv_cb_list)) {
 159                         req = list_first_entry(&serv->sv_cb_list,
 160                                         struct rpc_rqst, rq_bc_list);
 161                         list_del(&req->rq_bc_list);
 162                         spin_unlock_bh(&serv->sv_cb_lock);
 163                         dprintk("Invoking bc_svc_process()\n");
 164                         error = bc_svc_process(serv, req, rqstp);
 165                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 166                                 error);
 167                 } else {
 168                         spin_unlock_bh(&serv->sv_cb_lock);
 169                         schedule();
 170                 }
 171                 finish_wait(&serv->sv_cb_waitq, &wq);
 172         }
 173         return 0;
 174 }
 175
 176 /*
 177  * Bring up the NFSv4.1 callback service
 178  */
 179 struct svc_rqst *
 180 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
 181 {
 182         struct svc_xprt *bc_xprt;
 183         struct svc_rqst *rqstp = ERR_PTR(-ENOMEM);
 184
 185         dprintk("--> %s\n", __func__);
 186         /* Create a svc_sock for the service */
 187         bc_xprt = svc_sock_create(serv, xprt->prot);
 188         if (!bc_xprt)
 189                 goto out;
 190
 191         /*
 192          * Save the svc_serv in the transport so that it can
 193          * be referenced when the session backchannel is initialized
 194          */
 195         serv->bc_xprt = bc_xprt;
 196         xprt->bc_serv = serv;
 197
 198         INIT_LIST_HEAD(&serv->sv_cb_list);
 199         spin_lock_init(&serv->sv_cb_lock);
 200         init_waitqueue_head(&serv->sv_cb_waitq);
 201         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
 202         if (IS_ERR(rqstp))
 203                 svc_sock_destroy(bc_xprt);
 204 out:
 205         dprintk("--> %s return %p\n", __func__, rqstp);
 206         return rqstp;
 207 }
 208
 209 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 210                 struct svc_serv *serv, struct rpc_xprt *xprt,
 211                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 212 {
 213         if (minorversion) {
 214                 *rqstpp = nfs41_callback_up(serv, xprt);
 215                 *callback_svc = nfs41_callback_svc;
 216         }
 217         return minorversion;
 218 }
 219
 220 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 221                 struct nfs_callback_data *cb_info)
 222 {
 223         if (minorversion)
 224                 xprt->bc_serv = cb_info->serv;
 225 }
 226 #else
 227 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 228                 struct svc_serv *serv, struct rpc_xprt *xprt,
 229                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 230 {
 231         return 0;
 232 }
 233
 234 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 235                 struct nfs_callback_data *cb_info)
 236 {
 237 }
 238 #endif /* CONFIG_NFS_V4_1 */
 239
 240 /*
 241  * Bring up the callback thread if it is not already up.
 242  */
 243 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 244 {
 245         struct svc_serv *serv = NULL;
 246         struct svc_rqst *rqstp;
 247         int (*callback_svc)(void *vrqstp);
 248         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 249         char svc_name[12];
 250         int ret = 0;
 251         int minorversion_setup;
 252
 253         mutex_lock(&nfs_callback_mutex);
 254         if (cb_info->users++ || cb_info->task != NULL) {
 255                 nfs_callback_bc_serv(minorversion, xprt, cb_info);
 256                 goto out;
 257         }
 258         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 259         if (!serv) {
 260                 ret = -ENOMEM;
 261                 goto out_err;
 262         }
 263
 264         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
 265                                         serv, xprt, &rqstp, &callback_svc);
 266         if (!minorversion_setup) {
 267                 /* v4.0 callback setup */
 268                 rqstp = nfs4_callback_up(serv);
 269                 callback_svc = nfs4_callback_svc;
 270         }
 271
 272         if (IS_ERR(rqstp)) {
 273                 ret = PTR_ERR(rqstp);
 274                 goto out_err;
 275         }
 276
 277         svc_sock_update_bufs(serv);
 278
 279         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 280         cb_info->serv = serv;
 281         cb_info->rqst = rqstp;
 282         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 283         if (IS_ERR(cb_info->task)) {
 284                 ret = PTR_ERR(cb_info->task);
 285                 svc_exit_thread(cb_info->rqst);
 286                 cb_info->rqst = NULL;
 287                 cb_info->task = NULL;
 288                 goto out_err;
 289         }
 290 out:
 291         /*
 292          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 293          * svc_prepare_thread increments that. So we need to call svc_destroy
 294          * on both success and failure so that the refcount is 1 when the
 295          * thread exits.
 296          */
 297         if (serv)
 298                 svc_destroy(serv);
 299         mutex_unlock(&nfs_callback_mutex);
 300         return ret;
 301 out_err:
 302         dprintk("NFS: Couldn't create callback socket or server thread; "
 303                 "err = %d\n", ret);
 304         cb_info->users--;
 305         goto out;
 306 }
 307
 308 /*
 309  * Kill the callback thread if it's no longer being used.
 310  */
 311 void nfs_callback_down(int minorversion)
 312 {
 313         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 314
 315         mutex_lock(&nfs_callback_mutex);
 316         cb_info->users--;
 317         if (cb_info->users == 0 && cb_info->task != NULL) {
 318                 kthread_stop(cb_info->task);
 319                 svc_exit_thread(cb_info->rqst);
 320                 cb_info->serv = NULL;
 321                 cb_info->rqst = NULL;
 322                 cb_info->task = NULL;
 323         }
 324         mutex_unlock(&nfs_callback_mutex);
 325 }
 326
 327 static int check_gss_callback_principal(struct nfs_client *clp,
 328                                         struct svc_rqst *rqstp)
 329 {
 330         struct rpc_clnt *r = clp->cl_rpcclient;
 331         char *p = svc_gss_principal(rqstp);
 332
 333         /*
 334          * It might just be a normal user principal, in which case
 335          * userspace won't bother to tell us the name at all.
 336          */
 337         if (p == NULL)
 338                 return SVC_DENIED;
 339
 340         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 341
 342         if (memcmp(p, "nfs@", 4) != 0)
 343                 return SVC_DENIED;
 344         p += 4;
 345         if (strcmp(p, r->cl_server) != 0)
 346                 return SVC_DENIED;
 347         return SVC_OK;
 348 }
 349
 350 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 351 {
 352         struct nfs_client *clp;
 353         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 354         int ret = SVC_OK;
 355
 356         /* Don't talk to strangers */
 357         clp = nfs_find_client(svc_addr(rqstp), 4);
 358         if (clp == NULL)
 359                 return SVC_DROP;
 360
 361         dprintk("%s: %s NFSv4 callback!\n", __func__,
 362                         svc_print_addr(rqstp, buf, sizeof(buf)));
 363
 364         switch (rqstp->rq_authop->flavour) {
 365                 case RPC_AUTH_NULL:
 366                         if (rqstp->rq_proc != CB_NULL)
 367                                 ret = SVC_DENIED;
 368                         break;
 369                 case RPC_AUTH_UNIX:
 370                         break;
 371                 case RPC_AUTH_GSS:
 372                         ret = check_gss_callback_principal(clp, rqstp);
 373                         break;
 374                 default:
 375                         ret = SVC_DENIED;
 376         }
 377         nfs_put_client(clp);
 378         return ret;
 379 }
 380
 381 /*
 382  * Define NFS4 callback program
 383  */
 384 static struct svc_version *nfs4_callback_version[] = {
 385         [1] = &nfs4_callback_version1,
 386         [4] = &nfs4_callback_version4,
 387 };
 388
 389 static struct svc_stat nfs4_callback_stats;
 390
 391 static struct svc_program nfs4_callback_program = {
 392         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 393         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 394         .pg_vers = nfs4_callback_version,               /* version table */
 395         .pg_name = "NFSv4 callback",                    /* service name */
 396         .pg_class = "nfs",                              /* authentication class */
 397         .pg_stats = &nfs4_callback_stats,
 398         .pg_authenticate = nfs_callback_authenticate,
 399 };