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/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
  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 DECLARE_MUTEX(nfs_callback_sema);
  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         while (nfs_callback_info.users != 0 || !signalled()) {
  59                 /*
  60                  * Listen for a request on the socket
  61                  */
  62                 err = svc_recv(serv, rqstp, MAX_SCHEDULE_TIMEOUT);
  63                 if (err == -EAGAIN || err == -EINTR)
  64                         continue;
  65                 if (err < 0) {
  66                         printk(KERN_WARNING
  67                                         "%s: terminating on error %d\n",
  68                                         __FUNCTION__, -err);
  69                         break;
  70                 }
  71                 dprintk("%s: request from %u.%u.%u.%u\n", __FUNCTION__,
  72                                 NIPQUAD(rqstp->rq_addr.sin_addr.s_addr));
  73                 svc_process(serv, rqstp);
  74         }
  75
  76         svc_exit_thread(rqstp);
  77         nfs_callback_info.pid = 0;
  78         complete(&nfs_callback_info.stopped);
  79         unlock_kernel();
  80         module_put_and_exit(0);
  81 }
  82
  83 /*
  84  * Bring up the server process if it is not already up.
  85  */
  86 int nfs_callback_up(void)
  87 {
  88         struct svc_serv *serv;
  89         struct svc_sock *svsk;
  90         int ret = 0;
  91
  92         lock_kernel();
  93         down(&nfs_callback_sema);
  94         if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
  95                 goto out;
  96         init_completion(&nfs_callback_info.started);
  97         init_completion(&nfs_callback_info.stopped);
  98         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE);
  99         ret = -ENOMEM;
 100         if (!serv)
 101                 goto out_err;
 102         /* FIXME: We don't want to register this socket with the portmapper */
 103         ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport);
 104         if (ret < 0)
 105                 goto out_destroy;
 106         if (!list_empty(&serv->sv_permsocks)) {
 107                 svsk = list_entry(serv->sv_permsocks.next,
 108                                 struct svc_sock, sk_list);
 109                 nfs_callback_tcpport = ntohs(inet_sk(svsk->sk_sk)->sport);
 110                 dprintk ("Callback port = 0x%x\n", nfs_callback_tcpport);
 111         } else
 112                 BUG();
 113         ret = svc_create_thread(nfs_callback_svc, serv);
 114         if (ret < 0)
 115                 goto out_destroy;
 116         nfs_callback_info.serv = serv;
 117         wait_for_completion(&nfs_callback_info.started);
 118 out:
 119         up(&nfs_callback_sema);
 120         unlock_kernel();
 121         return ret;
 122 out_destroy:
 123         svc_destroy(serv);
 124 out_err:
 125         nfs_callback_info.users--;
 126         goto out;
 127 }
 128
 129 /*
 130  * Kill the server process if it is not already up.
 131  */
 132 int nfs_callback_down(void)
 133 {
 134         int ret = 0;
 135
 136         lock_kernel();
 137         down(&nfs_callback_sema);
 138         if (--nfs_callback_info.users || nfs_callback_info.pid == 0)
 139                 goto out;
 140         kill_proc(nfs_callback_info.pid, SIGKILL, 1);
 141         wait_for_completion(&nfs_callback_info.stopped);
 142 out:
 143         up(&nfs_callback_sema);
 144         unlock_kernel();
 145         return ret;
 146 }
 147
 148 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 149 {
 150         struct in_addr *addr = &rqstp->rq_addr.sin_addr;
 151         struct nfs4_client *clp;
 152
 153         /* Don't talk to strangers */
 154         clp = nfs4_find_client(addr);
 155         if (clp == NULL)
 156                 return SVC_DROP;
 157         dprintk("%s: %u.%u.%u.%u NFSv4 callback!\n", __FUNCTION__, NIPQUAD(addr));
 158         nfs4_put_client(clp);
 159         switch (rqstp->rq_authop->flavour) {
 160                 case RPC_AUTH_NULL:
 161                         if (rqstp->rq_proc != CB_NULL)
 162                                 return SVC_DENIED;
 163                         break;
 164                 case RPC_AUTH_UNIX:
 165                         break;
 166                 case RPC_AUTH_GSS:
 167                         /* FIXME: RPCSEC_GSS handling? */
 168                 default:
 169                         return SVC_DENIED;
 170         }
 171         return SVC_OK;
 172 }
 173
 174 /*
 175  * Define NFS4 callback program
 176  */
 177 extern struct svc_version nfs4_callback_version1;
 178
 179 static struct svc_version *nfs4_callback_version[] = {
 180         [1] = &nfs4_callback_version1,
 181 };
 182
 183 static struct svc_stat nfs4_callback_stats;
 184
 185 static struct svc_program nfs4_callback_program = {
 186         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 187         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 188         .pg_vers = nfs4_callback_version,               /* version table */
 189         .pg_name = "NFSv4 callback",                    /* service name */
 190         .pg_class = "nfs",                              /* authentication class */
 191         .pg_stats = &nfs4_callback_stats,
 192         .pg_authenticate = nfs_callback_authenticate,
 193 };