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  *  * CB_SEQUENCE operations will fail until the callback sessionid is set.
 139  *   */
 140 int nfs4_set_callback_sessionid(struct nfs_client *clp)
 141 {
 142         struct svc_serv *serv = clp->cl_rpcclient->cl_xprt->bc_serv;
 143         struct nfs4_sessionid *bc_sid;
 144
 145         if (!serv->sv_bc_xprt)
 146                 return -EINVAL;
 147
 148         /* on success freed in xprt_free */
 149         bc_sid = kmalloc(sizeof(struct nfs4_sessionid), GFP_KERNEL);
 150         if (!bc_sid)
 151                 return -ENOMEM;
 152         memcpy(bc_sid->data, &clp->cl_session->sess_id.data,
 153                 NFS4_MAX_SESSIONID_LEN);
 154         spin_lock_bh(&serv->sv_cb_lock);
 155         serv->sv_bc_xprt->xpt_bc_sid = bc_sid;
 156         spin_unlock_bh(&serv->sv_cb_lock);
 157         dprintk("%s set xpt_bc_sid=%u:%u:%u:%u for sv_bc_xprt %p\n", __func__,
 158                 ((u32 *)bc_sid->data)[0], ((u32 *)bc_sid->data)[1],
 159                 ((u32 *)bc_sid->data)[2], ((u32 *)bc_sid->data)[3],
 160                 serv->sv_bc_xprt);
 161         return 0;
 162 }
 163
 164 /*
 165  * The callback service for NFSv4.1 callbacks
 166  */
 167 static int
 168 nfs41_callback_svc(void *vrqstp)
 169 {
 170         struct svc_rqst *rqstp = vrqstp;
 171         struct svc_serv *serv = rqstp->rq_server;
 172         struct rpc_rqst *req;
 173         int error;
 174         DEFINE_WAIT(wq);
 175
 176         set_freezable();
 177
 178         while (!kthread_should_stop()) {
 179                 prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
 180                 spin_lock_bh(&serv->sv_cb_lock);
 181                 if (!list_empty(&serv->sv_cb_list)) {
 182                         req = list_first_entry(&serv->sv_cb_list,
 183                                         struct rpc_rqst, rq_bc_list);
 184                         list_del(&req->rq_bc_list);
 185                         spin_unlock_bh(&serv->sv_cb_lock);
 186                         dprintk("Invoking bc_svc_process()\n");
 187                         error = bc_svc_process(serv, req, rqstp);
 188                         dprintk("bc_svc_process() returned w/ error code= %d\n",
 189                                 error);
 190                 } else {
 191                         spin_unlock_bh(&serv->sv_cb_lock);
 192                         schedule();
 193                 }
 194                 finish_wait(&serv->sv_cb_waitq, &wq);
 195         }
 196         return 0;
 197 }
 198
 199 /*
 200  * Bring up the NFSv4.1 callback service
 201  */
 202 struct svc_rqst *
 203 nfs41_callback_up(struct svc_serv *serv, struct rpc_xprt *xprt)
 204 {
 205         struct svc_rqst *rqstp;
 206         int ret;
 207
 208         /*
 209          * Create an svc_sock for the back channel service that shares the
 210          * fore channel connection.
 211          * Returns the input port (0) and sets the svc_serv bc_xprt on success
 212          */
 213         ret = svc_create_xprt(serv, "tcp-bc", &init_net, PF_INET, 0,
 214                               SVC_SOCK_ANONYMOUS);
 215         if (ret < 0) {
 216                 rqstp = ERR_PTR(ret);
 217                 goto out;
 218         }
 219
 220         /*
 221          * Save the svc_serv in the transport so that it can
 222          * be referenced when the session backchannel is initialized
 223          */
 224         xprt->bc_serv = serv;
 225
 226         INIT_LIST_HEAD(&serv->sv_cb_list);
 227         spin_lock_init(&serv->sv_cb_lock);
 228         init_waitqueue_head(&serv->sv_cb_waitq);
 229         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
 230         if (IS_ERR(rqstp)) {
 231                 svc_xprt_put(serv->sv_bc_xprt);
 232                 serv->sv_bc_xprt = NULL;
 233         }
 234 out:
 235         dprintk("--> %s return %ld\n", __func__,
 236                 IS_ERR(rqstp) ? PTR_ERR(rqstp) : 0);
 237         return rqstp;
 238 }
 239
 240 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 241                 struct svc_serv *serv, struct rpc_xprt *xprt,
 242                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 243 {
 244         if (minorversion) {
 245                 *rqstpp = nfs41_callback_up(serv, xprt);
 246                 *callback_svc = nfs41_callback_svc;
 247         }
 248         return minorversion;
 249 }
 250
 251 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 252                 struct nfs_callback_data *cb_info)
 253 {
 254         if (minorversion)
 255                 xprt->bc_serv = cb_info->serv;
 256 }
 257 #else
 258 static inline int nfs_minorversion_callback_svc_setup(u32 minorversion,
 259                 struct svc_serv *serv, struct rpc_xprt *xprt,
 260                 struct svc_rqst **rqstpp, int (**callback_svc)(void *vrqstp))
 261 {
 262         return 0;
 263 }
 264
 265 static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
 266                 struct nfs_callback_data *cb_info)
 267 {
 268 }
 269 int nfs4_set_callback_sessionid(struct nfs_client *clp)
 270 {
 271         return 0;
 272 }
 273 #endif /* CONFIG_NFS_V4_1 */
 274
 275 /*
 276  * Bring up the callback thread if it is not already up.
 277  */
 278 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 279 {
 280         struct svc_serv *serv = NULL;
 281         struct svc_rqst *rqstp;
 282         int (*callback_svc)(void *vrqstp);
 283         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 284         char svc_name[12];
 285         int ret = 0;
 286         int minorversion_setup;
 287
 288         mutex_lock(&nfs_callback_mutex);
 289         if (cb_info->users++ || cb_info->task != NULL) {
 290                 nfs_callback_bc_serv(minorversion, xprt, cb_info);
 291                 goto out;
 292         }
 293         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 294         if (!serv) {
 295                 ret = -ENOMEM;
 296                 goto out_err;
 297         }
 298
 299         minorversion_setup =  nfs_minorversion_callback_svc_setup(minorversion,
 300                                         serv, xprt, &rqstp, &callback_svc);
 301         if (!minorversion_setup) {
 302                 /* v4.0 callback setup */
 303                 rqstp = nfs4_callback_up(serv);
 304                 callback_svc = nfs4_callback_svc;
 305         }
 306
 307         if (IS_ERR(rqstp)) {
 308                 ret = PTR_ERR(rqstp);
 309                 goto out_err;
 310         }
 311
 312         svc_sock_update_bufs(serv);
 313
 314         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 315         cb_info->serv = serv;
 316         cb_info->rqst = rqstp;
 317         cb_info->task = kthread_run(callback_svc, cb_info->rqst, svc_name);
 318         if (IS_ERR(cb_info->task)) {
 319                 ret = PTR_ERR(cb_info->task);
 320                 svc_exit_thread(cb_info->rqst);
 321                 cb_info->rqst = NULL;
 322                 cb_info->task = NULL;
 323                 goto out_err;
 324         }
 325 out:
 326         /*
 327          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 328          * svc_prepare_thread increments that. So we need to call svc_destroy
 329          * on both success and failure so that the refcount is 1 when the
 330          * thread exits.
 331          */
 332         if (serv)
 333                 svc_destroy(serv);
 334         mutex_unlock(&nfs_callback_mutex);
 335         return ret;
 336 out_err:
 337         dprintk("NFS: Couldn't create callback socket or server thread; "
 338                 "err = %d\n", ret);
 339         cb_info->users--;
 340         goto out;
 341 }
 342
 343 /*
 344  * Kill the callback thread if it's no longer being used.
 345  */
 346 void nfs_callback_down(int minorversion)
 347 {
 348         struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 349
 350         mutex_lock(&nfs_callback_mutex);
 351         cb_info->users--;
 352         if (cb_info->users == 0 && cb_info->task != NULL) {
 353                 kthread_stop(cb_info->task);
 354                 svc_exit_thread(cb_info->rqst);
 355                 cb_info->serv = NULL;
 356                 cb_info->rqst = NULL;
 357                 cb_info->task = NULL;
 358         }
 359         mutex_unlock(&nfs_callback_mutex);
 360 }
 361
 362 static int check_gss_callback_principal(struct nfs_client *clp,
 363                                         struct svc_rqst *rqstp)
 364 {
 365         struct rpc_clnt *r = clp->cl_rpcclient;
 366         char *p = svc_gss_principal(rqstp);
 367
 368         /* No RPC_AUTH_GSS on NFSv4.1 back channel yet */
 369         if (clp->cl_minorversion != 0)
 370                 return SVC_DROP;
 371         /*
 372          * It might just be a normal user principal, in which case
 373          * userspace won't bother to tell us the name at all.
 374          */
 375         if (p == NULL)
 376                 return SVC_DENIED;
 377
 378         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 379
 380         if (memcmp(p, "nfs@", 4) != 0)
 381                 return SVC_DENIED;
 382         p += 4;
 383         if (strcmp(p, r->cl_server) != 0)
 384                 return SVC_DENIED;
 385         return SVC_OK;
 386 }
 387
 388 /* pg_authenticate method helper */
 389 static struct nfs_client *nfs_cb_find_client(struct svc_rqst *rqstp)
 390 {
 391         struct nfs4_sessionid *sessionid = bc_xprt_sid(rqstp);
 392         int is_cb_compound = rqstp->rq_proc == CB_COMPOUND ? 1 : 0;
 393
 394         dprintk("--> %s rq_proc %d\n", __func__, rqstp->rq_proc);
 395         if (svc_is_backchannel(rqstp))
 396                 /* Sessionid (usually) set after CB_NULL ping */
 397                 return nfs4_find_client_sessionid(svc_addr(rqstp), sessionid,
 398                                                   is_cb_compound);
 399         else
 400                 /* No callback identifier in pg_authenticate */
 401                 return nfs4_find_client_no_ident(svc_addr(rqstp));
 402 }
 403
 404 /* pg_authenticate method for nfsv4 callback threads. */
 405 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 406 {
 407         struct nfs_client *clp;
 408         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 409         int ret = SVC_OK;
 410
 411         /* Don't talk to strangers */
 412         clp = nfs_cb_find_client(rqstp);
 413         if (clp == NULL)
 414                 return SVC_DROP;
 415
 416         dprintk("%s: %s NFSv4 callback!\n", __func__,
 417                         svc_print_addr(rqstp, buf, sizeof(buf)));
 418
 419         switch (rqstp->rq_authop->flavour) {
 420                 case RPC_AUTH_NULL:
 421                         if (rqstp->rq_proc != CB_NULL)
 422                                 ret = SVC_DENIED;
 423                         break;
 424                 case RPC_AUTH_UNIX:
 425                         break;
 426                 case RPC_AUTH_GSS:
 427                         ret = check_gss_callback_principal(clp, rqstp);
 428                         break;
 429                 default:
 430                         ret = SVC_DENIED;
 431         }
 432         nfs_put_client(clp);
 433         return ret;
 434 }
 435
 436 /*
 437  * Define NFS4 callback program
 438  */
 439 static struct svc_version *nfs4_callback_version[] = {
 440         [1] = &nfs4_callback_version1,
 441         [4] = &nfs4_callback_version4,
 442 };
 443
 444 static struct svc_stat nfs4_callback_stats;
 445
 446 static struct svc_program nfs4_callback_program = {
 447         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 448         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 449         .pg_vers = nfs4_callback_version,               /* version table */
 450         .pg_name = "NFSv4 callback",                    /* service name */
 451         .pg_class = "nfs",                              /* authentication class */
 452         .pg_stats = &nfs4_callback_stats,
 453         .pg_authenticate = nfs_callback_authenticate,
 454 };