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   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
  18 #include <net/inet_sock.h>
  19
  20 #include "nfs4_fs.h"
  21 #include "callback.h"
  22
  23 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  24
  25 struct nfs_callback_data {
  26         unsigned int users;
  27         struct svc_serv *serv;
  28         pid_t pid;
  29         struct completion started;
  30         struct completion stopped;
  31 };
  32
  33 static struct nfs_callback_data nfs_callback_info;
  34 static DEFINE_MUTEX(nfs_callback_mutex);
  35 static struct svc_program nfs4_callback_program;
  36
  37 unsigned int nfs_callback_set_tcpport;
  38 unsigned short nfs_callback_tcpport;
  39
  40 /*
  41  * This is the callback kernel thread.
  42  */
  43 static void nfs_callback_svc(struct svc_rqst *rqstp)
  44 {
  45         struct svc_serv *serv = rqstp->rq_server;
  46         int err;
  47
  48         __module_get(THIS_MODULE);
  49         lock_kernel();
  50
  51         nfs_callback_info.pid = current->pid;
  52         daemonize("nfsv4-svc");
  53         /* Process request with signals blocked, but allow SIGKILL.  */
  54         allow_signal(SIGKILL);
  55
  56         complete(&nfs_callback_info.started);
  57
  58         for(;;) {
  59                 if (signalled()) {
  60                         if (nfs_callback_info.users == 0)
  61                                 break;
  62                         flush_signals(current);
  63                 }
  64                 /*
  65                  * Listen for a request on the socket
  66                  */
  67                 err = svc_recv(serv, rqstp, MAX_SCHEDULE_TIMEOUT);
  68                 if (err == -EAGAIN || err == -EINTR)
  69                         continue;
  70                 if (err < 0) {
  71                         printk(KERN_WARNING
  72                                         "%s: terminating on error %d\n",
  73                                         __FUNCTION__, -err);
  74                         break;
  75                 }
  76                 dprintk("%s: request from %u.%u.%u.%u\n", __FUNCTION__,
  77                                 NIPQUAD(rqstp->rq_addr.sin_addr.s_addr));
  78                 svc_process(serv, rqstp);
  79         }
  80
  81         svc_exit_thread(rqstp);
  82         nfs_callback_info.pid = 0;
  83         complete(&nfs_callback_info.stopped);
  84         unlock_kernel();
  85         module_put_and_exit(0);
  86 }
  87
  88 /*
  89  * Bring up the server process if it is not already up.
  90  */
  91 int nfs_callback_up(void)
  92 {
  93         struct svc_serv *serv;
  94         struct svc_sock *svsk;
  95         int ret = 0;
  96
  97         lock_kernel();
  98         mutex_lock(&nfs_callback_mutex);
  99         if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
 100                 goto out;
 101         init_completion(&nfs_callback_info.started);
 102         init_completion(&nfs_callback_info.stopped);
 103         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE);
 104         ret = -ENOMEM;
 105         if (!serv)
 106                 goto out_err;
 107         /* FIXME: We don't want to register this socket with the portmapper */
 108         ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport);
 109         if (ret < 0)
 110                 goto out_destroy;
 111         if (!list_empty(&serv->sv_permsocks)) {
 112                 svsk = list_entry(serv->sv_permsocks.next,
 113                                 struct svc_sock, sk_list);
 114                 nfs_callback_tcpport = ntohs(inet_sk(svsk->sk_sk)->sport);
 115                 dprintk ("Callback port = 0x%x\n", nfs_callback_tcpport);
 116         } else
 117                 BUG();
 118         ret = svc_create_thread(nfs_callback_svc, serv);
 119         if (ret < 0)
 120                 goto out_destroy;
 121         nfs_callback_info.serv = serv;
 122         wait_for_completion(&nfs_callback_info.started);
 123 out:
 124         mutex_unlock(&nfs_callback_mutex);
 125         unlock_kernel();
 126         return ret;
 127 out_destroy:
 128         svc_destroy(serv);
 129 out_err:
 130         nfs_callback_info.users--;
 131         goto out;
 132 }
 133
 134 /*
 135  * Kill the server process if it is not already up.
 136  */
 137 int nfs_callback_down(void)
 138 {
 139         int ret = 0;
 140
 141         lock_kernel();
 142         mutex_lock(&nfs_callback_mutex);
 143         nfs_callback_info.users--;
 144         do {
 145                 if (nfs_callback_info.users != 0 || nfs_callback_info.pid == 0)
 146                         break;
 147                 if (kill_proc(nfs_callback_info.pid, SIGKILL, 1) < 0)
 148                         break;
 149         } while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0);
 150         mutex_unlock(&nfs_callback_mutex);
 151         unlock_kernel();
 152         return ret;
 153 }
 154
 155 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 156 {
 157         struct in_addr *addr = &rqstp->rq_addr.sin_addr;
 158         struct nfs4_client *clp;
 159
 160         /* Don't talk to strangers */
 161         clp = nfs4_find_client(addr);
 162         if (clp == NULL)
 163                 return SVC_DROP;
 164         dprintk("%s: %u.%u.%u.%u NFSv4 callback!\n", __FUNCTION__, NIPQUAD(addr));
 165         nfs4_put_client(clp);
 166         switch (rqstp->rq_authop->flavour) {
 167                 case RPC_AUTH_NULL:
 168                         if (rqstp->rq_proc != CB_NULL)
 169                                 return SVC_DENIED;
 170                         break;
 171                 case RPC_AUTH_UNIX:
 172                         break;
 173                 case RPC_AUTH_GSS:
 174                         /* FIXME: RPCSEC_GSS handling? */
 175                 default:
 176                         return SVC_DENIED;
 177         }
 178         return SVC_OK;
 179 }
 180
 181 /*
 182  * Define NFS4 callback program
 183  */
 184 static struct svc_version *nfs4_callback_version[] = {
 185         [1] = &nfs4_callback_version1,
 186 };
 187
 188 static struct svc_stat nfs4_callback_stats;
 189
 190 static struct svc_program nfs4_callback_program = {
 191         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 192         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 193         .pg_vers = nfs4_callback_version,               /* version table */
 194         .pg_name = "NFSv4 callback",                    /* service name */
 195         .pg_class = "nfs",                              /* authentication class */
 196         .pg_stats = &nfs4_callback_stats,
 197         .pg_authenticate = nfs_callback_authenticate,
 198 };