git.oblomov.eu Git - linux-2.6/blob - 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
  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_rqst *rqst;
  32         struct task_struct *task;
  33 };
  34
  35 static struct nfs_callback_data nfs_callback_info;
  36 static DEFINE_MUTEX(nfs_callback_mutex);
  37 static struct svc_program nfs4_callback_program;
  38
  39 unsigned int nfs_callback_set_tcpport;
  40 unsigned short nfs_callback_tcpport;
  41 unsigned short nfs_callback_tcpport6;
  42 static const int nfs_set_port_min = 0;
  43 static const int nfs_set_port_max = 65535;
  44
  45 static int param_set_port(const char *val, struct kernel_param *kp)
  46 {
  47         char *endp;
  48         int num = simple_strtol(val, &endp, 0);
  49         if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
  50                 return -EINVAL;
  51         *((int *)kp->arg) = num;
  52         return 0;
  53 }
  54
  55 module_param_call(callback_tcpport, param_set_port, param_get_int,
  56                  &nfs_callback_set_tcpport, 0644);
  57
  58 /*
  59  * This is the callback kernel thread.
  60  */
  61 static int
  62 nfs4_callback_svc(void *vrqstp)
  63 {
  64         int err, preverr = 0;
  65         struct svc_rqst *rqstp = vrqstp;
  66
  67         set_freezable();
  68
  69         /*
  70          * FIXME: do we really need to run this under the BKL? If so, please
  71          * add a comment about what it's intended to protect.
  72          */
  73         lock_kernel();
  74         while (!kthread_should_stop()) {
  75                 /*
  76                  * Listen for a request on the socket
  77                  */
  78                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  79                 if (err == -EAGAIN || err == -EINTR) {
  80                         preverr = err;
  81                         continue;
  82                 }
  83                 if (err < 0) {
  84                         if (err != preverr) {
  85                                 printk(KERN_WARNING "%s: unexpected error "
  86                                         "from svc_recv (%d)\n", __func__, err);
  87                                 preverr = err;
  88                         }
  89                         schedule_timeout_uninterruptible(HZ);
  90                         continue;
  91                 }
  92                 preverr = err;
  93                 svc_process(rqstp);
  94         }
  95         unlock_kernel();
  96         return 0;
  97 }
  98
  99 /*
 100  * Prepare to bring up the NFSv4 callback service
 101  */
 102 struct svc_rqst *
 103 nfs4_callback_up(struct svc_serv *serv)
 104 {
 105         int ret;
 106
 107         ret = svc_create_xprt(serv, "tcp", PF_INET,
 108                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
 109         if (ret <= 0)
 110                 goto out_err;
 111         nfs_callback_tcpport = ret;
 112         dprintk("NFS: Callback listener port = %u (af %u)\n",
 113                         nfs_callback_tcpport, PF_INET);
 114
 115 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 116         ret = svc_create_xprt(serv, "tcp", PF_INET6,
 117                                 nfs_callback_set_tcpport, SVC_SOCK_ANONYMOUS);
 118         if (ret > 0) {
 119                 nfs_callback_tcpport6 = ret;
 120                 dprintk("NFS: Callback listener port = %u (af %u)\n",
 121                                 nfs_callback_tcpport6, PF_INET6);
 122         } else if (ret != -EAFNOSUPPORT)
 123                 goto out_err;
 124 #endif  /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
 125
 126         return svc_prepare_thread(serv, &serv->sv_pools[0]);
 127
 128 out_err:
 129         if (ret == 0)
 130                 ret = -ENOMEM;
 131         return ERR_PTR(ret);
 132 }
 133
 134 /*
 135  * Bring up the callback thread if it is not already up.
 136  */
 137 int nfs_callback_up(u32 minorversion, struct rpc_xprt *xprt)
 138 {
 139         struct svc_serv *serv = NULL;
 140         struct svc_rqst *rqstp;
 141         int (*callback_svc)(void *vrqstp);
 142         char svc_name[12];
 143         int ret = 0;
 144
 145         mutex_lock(&nfs_callback_mutex);
 146         if (nfs_callback_info.users++ || nfs_callback_info.task != NULL)
 147                 goto out;
 148         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 149         if (!serv) {
 150                 ret = -ENOMEM;
 151                 goto out_err;
 152         }
 153
 154         if (!minorversion) {
 155                 rqstp = nfs4_callback_up(serv);
 156                 callback_svc = nfs4_callback_svc;
 157         } else {
 158                 BUG();  /* for now */
 159         }
 160
 161         if (IS_ERR(rqstp)) {
 162                 ret = PTR_ERR(rqstp);
 163                 goto out_err;
 164         }
 165
 166         svc_sock_update_bufs(serv);
 167
 168         sprintf(svc_name, "nfsv4.%u-svc", minorversion);
 169         nfs_callback_info.rqst = rqstp;
 170         nfs_callback_info.task = kthread_run(callback_svc,
 171                                              nfs_callback_info.rqst,
 172                                              svc_name);
 173         if (IS_ERR(nfs_callback_info.task)) {
 174                 ret = PTR_ERR(nfs_callback_info.task);
 175                 svc_exit_thread(nfs_callback_info.rqst);
 176                 nfs_callback_info.rqst = NULL;
 177                 nfs_callback_info.task = NULL;
 178                 goto out_err;
 179         }
 180 out:
 181         /*
 182          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 183          * svc_prepare_thread increments that. So we need to call svc_destroy
 184          * on both success and failure so that the refcount is 1 when the
 185          * thread exits.
 186          */
 187         if (serv)
 188                 svc_destroy(serv);
 189         mutex_unlock(&nfs_callback_mutex);
 190         return ret;
 191 out_err:
 192         dprintk("NFS: Couldn't create callback socket or server thread; "
 193                 "err = %d\n", ret);
 194         nfs_callback_info.users--;
 195         goto out;
 196 }
 197
 198 /*
 199  * Kill the callback thread if it's no longer being used.
 200  */
 201 void nfs_callback_down(void)
 202 {
 203         mutex_lock(&nfs_callback_mutex);
 204         nfs_callback_info.users--;
 205         if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) {
 206                 kthread_stop(nfs_callback_info.task);
 207                 svc_exit_thread(nfs_callback_info.rqst);
 208                 nfs_callback_info.rqst = NULL;
 209                 nfs_callback_info.task = NULL;
 210         }
 211         mutex_unlock(&nfs_callback_mutex);
 212 }
 213
 214 static int check_gss_callback_principal(struct nfs_client *clp,
 215                                         struct svc_rqst *rqstp)
 216 {
 217         struct rpc_clnt *r = clp->cl_rpcclient;
 218         char *p = svc_gss_principal(rqstp);
 219
 220         /*
 221          * It might just be a normal user principal, in which case
 222          * userspace won't bother to tell us the name at all.
 223          */
 224         if (p == NULL)
 225                 return SVC_DENIED;
 226
 227         /* Expect a GSS_C_NT_HOSTBASED_NAME like "nfs@serverhostname" */
 228
 229         if (memcmp(p, "nfs@", 4) != 0)
 230                 return SVC_DENIED;
 231         p += 4;
 232         if (strcmp(p, r->cl_server) != 0)
 233                 return SVC_DENIED;
 234         return SVC_OK;
 235 }
 236
 237 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 238 {
 239         struct nfs_client *clp;
 240         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 241         int ret = SVC_OK;
 242
 243         /* Don't talk to strangers */
 244         clp = nfs_find_client(svc_addr(rqstp), 4);
 245         if (clp == NULL)
 246                 return SVC_DROP;
 247
 248         dprintk("%s: %s NFSv4 callback!\n", __func__,
 249                         svc_print_addr(rqstp, buf, sizeof(buf)));
 250
 251         switch (rqstp->rq_authop->flavour) {
 252                 case RPC_AUTH_NULL:
 253                         if (rqstp->rq_proc != CB_NULL)
 254                                 ret = SVC_DENIED;
 255                         break;
 256                 case RPC_AUTH_UNIX:
 257                         break;
 258                 case RPC_AUTH_GSS:
 259                         ret = check_gss_callback_principal(clp, rqstp);
 260                         break;
 261                 default:
 262                         ret = SVC_DENIED;
 263         }
 264         nfs_put_client(clp);
 265         return ret;
 266 }
 267
 268 /*
 269  * Define NFS4 callback program
 270  */
 271 static struct svc_version *nfs4_callback_version[] = {
 272         [1] = &nfs4_callback_version1,
 273 };
 274
 275 static struct svc_stat nfs4_callback_stats;
 276
 277 static struct svc_program nfs4_callback_program = {
 278         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 279         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 280         .pg_vers = nfs4_callback_version,               /* version table */
 281         .pg_name = "NFSv4 callback",                    /* service name */
 282         .pg_class = "nfs",                              /* authentication class */
 283         .pg_stats = &nfs4_callback_stats,
 284         .pg_authenticate = nfs_callback_authenticate,
 285 };