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