SAFE public projects git trees. - safe/jmp/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
  20 #include <net/inet_sock.h>
  21
  22 #include "nfs4_fs.h"
  23 #include "callback.h"
  24 #include "internal.h"
  25
  26 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  27
  28 struct nfs_callback_data {
  29         unsigned int users;
  30         struct svc_serv *serv;
  31         struct task_struct *task;
  32 };
  33
  34 static struct nfs_callback_data nfs_callback_info;
  35 static DEFINE_MUTEX(nfs_callback_mutex);
  36 static struct svc_program nfs4_callback_program;
  37
  38 unsigned int nfs_callback_set_tcpport;
  39 unsigned short nfs_callback_tcpport;
  40 static const int nfs_set_port_min = 0;
  41 static const int nfs_set_port_max = 65535;
  42
  43 static int param_set_port(const char *val, struct kernel_param *kp)
  44 {
  45         char *endp;
  46         int num = simple_strtol(val, &endp, 0);
  47         if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
  48                 return -EINVAL;
  49         *((int *)kp->arg) = num;
  50         return 0;
  51 }
  52
  53 module_param_call(callback_tcpport, param_set_port, param_get_int,
  54                  &nfs_callback_set_tcpport, 0644);
  55
  56 /*
  57  * This is the callback kernel thread.
  58  */
  59 static int
  60 nfs_callback_svc(void *vrqstp)
  61 {
  62         int err;
  63         struct svc_rqst *rqstp = vrqstp;
  64
  65         set_freezable();
  66
  67         /*
  68          * FIXME: do we really need to run this under the BKL? If so, please
  69          * add a comment about what it's intended to protect.
  70          */
  71         lock_kernel();
  72         while (!kthread_should_stop()) {
  73                 /*
  74                  * Listen for a request on the socket
  75                  */
  76                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  77                 if (err == -EAGAIN || err == -EINTR)
  78                         continue;
  79                 if (err < 0) {
  80                         printk(KERN_WARNING
  81                                         "%s: terminating on error %d\n",
  82                                         __FUNCTION__, -err);
  83                         break;
  84                 }
  85                 svc_process(rqstp);
  86         }
  87         unlock_kernel();
  88         nfs_callback_info.task = NULL;
  89         svc_exit_thread(rqstp);
  90         return 0;
  91 }
  92
  93 /*
  94  * Bring up the server process if it is not already up.
  95  */
  96 int nfs_callback_up(void)
  97 {
  98         struct svc_serv *serv = NULL;
  99         struct svc_rqst *rqstp;
 100         int ret = 0;
 101
 102         lock_kernel();
 103         mutex_lock(&nfs_callback_mutex);
 104         if (nfs_callback_info.users++ || nfs_callback_info.task != NULL)
 105                 goto out;
 106         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 107         ret = -ENOMEM;
 108         if (!serv)
 109                 goto out_err;
 110
 111         ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport,
 112                               SVC_SOCK_ANONYMOUS);
 113         if (ret <= 0)
 114                 goto out_err;
 115         nfs_callback_tcpport = ret;
 116         dprintk("Callback port = 0x%x\n", nfs_callback_tcpport);
 117
 118         rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]);
 119         if (IS_ERR(rqstp)) {
 120                 ret = PTR_ERR(rqstp);
 121                 goto out_err;
 122         }
 123
 124         svc_sock_update_bufs(serv);
 125         nfs_callback_info.serv = serv;
 126
 127         nfs_callback_info.task = kthread_run(nfs_callback_svc, rqstp,
 128                                              "nfsv4-svc");
 129         if (IS_ERR(nfs_callback_info.task)) {
 130                 ret = PTR_ERR(nfs_callback_info.task);
 131                 nfs_callback_info.serv = NULL;
 132                 nfs_callback_info.task = NULL;
 133                 svc_exit_thread(rqstp);
 134                 goto out_err;
 135         }
 136 out:
 137         /*
 138          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
 139          * svc_prepare_thread increments that. So we need to call svc_destroy
 140          * on both success and failure so that the refcount is 1 when the
 141          * thread exits.
 142          */
 143         if (serv)
 144                 svc_destroy(serv);
 145         mutex_unlock(&nfs_callback_mutex);
 146         unlock_kernel();
 147         return ret;
 148 out_err:
 149         dprintk("Couldn't create callback socket or server thread; err = %d\n",
 150                 ret);
 151         nfs_callback_info.users--;
 152         goto out;
 153 }
 154
 155 /*
 156  * Kill the server process if it is not already down.
 157  */
 158 void nfs_callback_down(void)
 159 {
 160         lock_kernel();
 161         mutex_lock(&nfs_callback_mutex);
 162         nfs_callback_info.users--;
 163         if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL)
 164                 kthread_stop(nfs_callback_info.task);
 165         mutex_unlock(&nfs_callback_mutex);
 166         unlock_kernel();
 167 }
 168
 169 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 170 {
 171         struct nfs_client *clp;
 172         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 173
 174         /* Don't talk to strangers */
 175         clp = nfs_find_client(svc_addr(rqstp), 4);
 176         if (clp == NULL)
 177                 return SVC_DROP;
 178
 179         dprintk("%s: %s NFSv4 callback!\n", __FUNCTION__,
 180                         svc_print_addr(rqstp, buf, sizeof(buf)));
 181         nfs_put_client(clp);
 182
 183         switch (rqstp->rq_authop->flavour) {
 184                 case RPC_AUTH_NULL:
 185                         if (rqstp->rq_proc != CB_NULL)
 186                                 return SVC_DENIED;
 187                         break;
 188                 case RPC_AUTH_UNIX:
 189                         break;
 190                 case RPC_AUTH_GSS:
 191                         /* FIXME: RPCSEC_GSS handling? */
 192                 default:
 193                         return SVC_DENIED;
 194         }
 195         return SVC_OK;
 196 }
 197
 198 /*
 199  * Define NFS4 callback program
 200  */
 201 static struct svc_version *nfs4_callback_version[] = {
 202         [1] = &nfs4_callback_version1,
 203 };
 204
 205 static struct svc_stat nfs4_callback_stats;
 206
 207 static struct svc_program nfs4_callback_program = {
 208         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 209         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 210         .pg_vers = nfs4_callback_version,               /* version table */
 211         .pg_name = "NFSv4 callback",                    /* service name */
 212         .pg_class = "nfs",                              /* authentication class */
 213         .pg_stats = &nfs4_callback_stats,
 214         .pg_authenticate = nfs_callback_authenticate,
 215 };