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