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