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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/config.h>
  10 #include <linux/completion.h>
  11 #include <linux/ip.h>
  12 #include <linux/module.h>
  13 #include <linux/smp_lock.h>
  14 #include <linux/sunrpc/svc.h>
  15 #include <linux/sunrpc/svcsock.h>
  16 #include <linux/nfs_fs.h>
  17 #include <linux/mutex.h>
  18
  19 #include <net/inet_sock.h>
  20
  21 #include "nfs4_fs.h"
  22 #include "callback.h"
  23
  24 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  25
  26 struct nfs_callback_data {
  27         unsigned int users;
  28         struct svc_serv *serv;
  29         pid_t pid;
  30         struct completion started;
  31         struct completion stopped;
  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
  41 /*
  42  * This is the callback kernel thread.
  43  */
  44 static void nfs_callback_svc(struct svc_rqst *rqstp)
  45 {
  46         struct svc_serv *serv = rqstp->rq_server;
  47         int err;
  48
  49         __module_get(THIS_MODULE);
  50         lock_kernel();
  51
  52         nfs_callback_info.pid = current->pid;
  53         daemonize("nfsv4-svc");
  54         /* Process request with signals blocked, but allow SIGKILL.  */
  55         allow_signal(SIGKILL);
  56
  57         complete(&nfs_callback_info.started);
  58
  59         for(;;) {
  60                 if (signalled()) {
  61                         if (nfs_callback_info.users == 0)
  62                                 break;
  63                         flush_signals(current);
  64                 }
  65                 /*
  66                  * Listen for a request on the socket
  67                  */
  68                 err = svc_recv(serv, rqstp, MAX_SCHEDULE_TIMEOUT);
  69                 if (err == -EAGAIN || err == -EINTR)
  70                         continue;
  71                 if (err < 0) {
  72                         printk(KERN_WARNING
  73                                         "%s: terminating on error %d\n",
  74                                         __FUNCTION__, -err);
  75                         break;
  76                 }
  77                 dprintk("%s: request from %u.%u.%u.%u\n", __FUNCTION__,
  78                                 NIPQUAD(rqstp->rq_addr.sin_addr.s_addr));
  79                 svc_process(serv, rqstp);
  80         }
  81
  82         svc_exit_thread(rqstp);
  83         nfs_callback_info.pid = 0;
  84         complete(&nfs_callback_info.stopped);
  85         unlock_kernel();
  86         module_put_and_exit(0);
  87 }
  88
  89 /*
  90  * Bring up the server process if it is not already up.
  91  */
  92 int nfs_callback_up(void)
  93 {
  94         struct svc_serv *serv;
  95         struct svc_sock *svsk;
  96         int ret = 0;
  97
  98         lock_kernel();
  99         mutex_lock(&nfs_callback_mutex);
 100         if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
 101                 goto out;
 102         init_completion(&nfs_callback_info.started);
 103         init_completion(&nfs_callback_info.stopped);
 104         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE);
 105         ret = -ENOMEM;
 106         if (!serv)
 107                 goto out_err;
 108         /* FIXME: We don't want to register this socket with the portmapper */
 109         ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport);
 110         if (ret < 0)
 111                 goto out_destroy;
 112         if (!list_empty(&serv->sv_permsocks)) {
 113                 svsk = list_entry(serv->sv_permsocks.next,
 114                                 struct svc_sock, sk_list);
 115                 nfs_callback_tcpport = ntohs(inet_sk(svsk->sk_sk)->sport);
 116                 dprintk ("Callback port = 0x%x\n", nfs_callback_tcpport);
 117         } else
 118                 BUG();
 119         ret = svc_create_thread(nfs_callback_svc, serv);
 120         if (ret < 0)
 121                 goto out_destroy;
 122         nfs_callback_info.serv = serv;
 123         wait_for_completion(&nfs_callback_info.started);
 124 out:
 125         mutex_unlock(&nfs_callback_mutex);
 126         unlock_kernel();
 127         return ret;
 128 out_destroy:
 129         svc_destroy(serv);
 130 out_err:
 131         nfs_callback_info.users--;
 132         goto out;
 133 }
 134
 135 /*
 136  * Kill the server process if it is not already up.
 137  */
 138 int nfs_callback_down(void)
 139 {
 140         int ret = 0;
 141
 142         lock_kernel();
 143         mutex_lock(&nfs_callback_mutex);
 144         nfs_callback_info.users--;
 145         do {
 146                 if (nfs_callback_info.users != 0 || nfs_callback_info.pid == 0)
 147                         break;
 148                 if (kill_proc(nfs_callback_info.pid, SIGKILL, 1) < 0)
 149                         break;
 150         } while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0);
 151         mutex_unlock(&nfs_callback_mutex);
 152         unlock_kernel();
 153         return ret;
 154 }
 155
 156 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 157 {
 158         struct in_addr *addr = &rqstp->rq_addr.sin_addr;
 159         struct nfs4_client *clp;
 160
 161         /* Don't talk to strangers */
 162         clp = nfs4_find_client(addr);
 163         if (clp == NULL)
 164                 return SVC_DROP;
 165         dprintk("%s: %u.%u.%u.%u NFSv4 callback!\n", __FUNCTION__, NIPQUAD(addr));
 166         nfs4_put_client(clp);
 167         switch (rqstp->rq_authop->flavour) {
 168                 case RPC_AUTH_NULL:
 169                         if (rqstp->rq_proc != CB_NULL)
 170                                 return SVC_DENIED;
 171                         break;
 172                 case RPC_AUTH_UNIX:
 173                         break;
 174                 case RPC_AUTH_GSS:
 175                         /* FIXME: RPCSEC_GSS handling? */
 176                 default:
 177                         return SVC_DENIED;
 178         }
 179         return SVC_OK;
 180 }
 181
 182 /*
 183  * Define NFS4 callback program
 184  */
 185 extern struct svc_version nfs4_callback_version1;
 186
 187 static struct svc_version *nfs4_callback_version[] = {
 188         [1] = &nfs4_callback_version1,
 189 };
 190
 191 static struct svc_stat nfs4_callback_stats;
 192
 193 static struct svc_program nfs4_callback_program = {
 194         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 195         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 196         .pg_vers = nfs4_callback_version,               /* version table */
 197         .pg_name = "NFSv4 callback",                    /* service name */
 198         .pg_class = "nfs",                              /* authentication class */
 199         .pg_stats = &nfs4_callback_stats,
 200         .pg_authenticate = nfs_callback_authenticate,
 201 };