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