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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/completion.h>
  10 #include <linux/ip.h>
  11 #include <linux/module.h>
  12 #include <linux/smp_lock.h>
  13 #include <linux/sunrpc/svc.h>
  14 #include <linux/sunrpc/svcsock.h>
  15 #include <linux/nfs_fs.h>
  16 #include <linux/mutex.h>
  17
  18 #include <net/inet_sock.h>
  19
  20 #include "nfs4_fs.h"
  21 #include "callback.h"
  22 #include "internal.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 static const int nfs_set_port_min = 0;
  41 static const int nfs_set_port_max = 65535;
  42
  43 static int param_set_port(const char *val, struct kernel_param *kp)
  44 {
  45         char *endp;
  46         int num = simple_strtol(val, &endp, 0);
  47         if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
  48                 return -EINVAL;
  49         *((int *)kp->arg) = num;
  50         return 0;
  51 }
  52
  53 module_param_call(callback_tcpport, param_set_port, param_get_int,
  54                  &nfs_callback_set_tcpport, 0644);
  55
  56 /*
  57  * This is the callback kernel thread.
  58  */
  59 static void nfs_callback_svc(struct svc_rqst *rqstp)
  60 {
  61         struct svc_serv *serv = rqstp->rq_server;
  62         int err;
  63
  64         __module_get(THIS_MODULE);
  65         lock_kernel();
  66
  67         nfs_callback_info.pid = current->pid;
  68         daemonize("nfsv4-svc");
  69         /* Process request with signals blocked, but allow SIGKILL.  */
  70         allow_signal(SIGKILL);
  71
  72         complete(&nfs_callback_info.started);
  73
  74         for(;;) {
  75                 if (signalled()) {
  76                         if (nfs_callback_info.users == 0)
  77                                 break;
  78                         flush_signals(current);
  79                 }
  80                 /*
  81                  * Listen for a request on the socket
  82                  */
  83                 err = svc_recv(serv, rqstp, MAX_SCHEDULE_TIMEOUT);
  84                 if (err == -EAGAIN || err == -EINTR)
  85                         continue;
  86                 if (err < 0) {
  87                         printk(KERN_WARNING
  88                                         "%s: terminating on error %d\n",
  89                                         __FUNCTION__, -err);
  90                         break;
  91                 }
  92                 dprintk("%s: request from %u.%u.%u.%u\n", __FUNCTION__,
  93                                 NIPQUAD(rqstp->rq_addr.sin_addr.s_addr));
  94                 svc_process(serv, rqstp);
  95         }
  96
  97         svc_exit_thread(rqstp);
  98         nfs_callback_info.pid = 0;
  99         complete(&nfs_callback_info.stopped);
 100         unlock_kernel();
 101         module_put_and_exit(0);
 102 }
 103
 104 /*
 105  * Bring up the server process if it is not already up.
 106  */
 107 int nfs_callback_up(void)
 108 {
 109         struct svc_serv *serv;
 110         struct svc_sock *svsk;
 111         int ret = 0;
 112
 113         lock_kernel();
 114         mutex_lock(&nfs_callback_mutex);
 115         if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
 116                 goto out;
 117         init_completion(&nfs_callback_info.started);
 118         init_completion(&nfs_callback_info.stopped);
 119         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE);
 120         ret = -ENOMEM;
 121         if (!serv)
 122                 goto out_err;
 123         /* FIXME: We don't want to register this socket with the portmapper */
 124         ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport);
 125         if (ret < 0)
 126                 goto out_destroy;
 127         if (!list_empty(&serv->sv_permsocks)) {
 128                 svsk = list_entry(serv->sv_permsocks.next,
 129                                 struct svc_sock, sk_list);
 130                 nfs_callback_tcpport = ntohs(inet_sk(svsk->sk_sk)->sport);
 131                 dprintk ("Callback port = 0x%x\n", nfs_callback_tcpport);
 132         } else
 133                 BUG();
 134         ret = svc_create_thread(nfs_callback_svc, serv);
 135         if (ret < 0)
 136                 goto out_destroy;
 137         nfs_callback_info.serv = serv;
 138         wait_for_completion(&nfs_callback_info.started);
 139 out:
 140         mutex_unlock(&nfs_callback_mutex);
 141         unlock_kernel();
 142         return ret;
 143 out_destroy:
 144         svc_destroy(serv);
 145 out_err:
 146         nfs_callback_info.users--;
 147         goto out;
 148 }
 149
 150 /*
 151  * Kill the server process if it is not already up.
 152  */
 153 void nfs_callback_down(void)
 154 {
 155         lock_kernel();
 156         mutex_lock(&nfs_callback_mutex);
 157         nfs_callback_info.users--;
 158         do {
 159                 if (nfs_callback_info.users != 0 || nfs_callback_info.pid == 0)
 160                         break;
 161                 if (kill_proc(nfs_callback_info.pid, SIGKILL, 1) < 0)
 162                         break;
 163         } while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0);
 164         mutex_unlock(&nfs_callback_mutex);
 165         unlock_kernel();
 166 }
 167
 168 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 169 {
 170         struct sockaddr_in *addr = &rqstp->rq_addr;
 171         struct nfs_client *clp;
 172
 173         /* Don't talk to strangers */
 174         clp = nfs_find_client(addr, 4);
 175         if (clp == NULL)
 176                 return SVC_DROP;
 177         dprintk("%s: %u.%u.%u.%u NFSv4 callback!\n", __FUNCTION__, NIPQUAD(addr->sin_addr));
 178         nfs_put_client(clp);
 179         switch (rqstp->rq_authop->flavour) {
 180                 case RPC_AUTH_NULL:
 181                         if (rqstp->rq_proc != CB_NULL)
 182                                 return SVC_DENIED;
 183                         break;
 184                 case RPC_AUTH_UNIX:
 185                         break;
 186                 case RPC_AUTH_GSS:
 187                         /* FIXME: RPCSEC_GSS handling? */
 188                 default:
 189                         return SVC_DENIED;
 190         }
 191         return SVC_OK;
 192 }
 193
 194 /*
 195  * Define NFS4 callback program
 196  */
 197 static struct svc_version *nfs4_callback_version[] = {
 198         [1] = &nfs4_callback_version1,
 199 };
 200
 201 static struct svc_stat nfs4_callback_stats;
 202
 203 static struct svc_program nfs4_callback_program = {
 204         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 205         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 206         .pg_vers = nfs4_callback_version,               /* version table */
 207         .pg_name = "NFSv4 callback",                    /* service name */
 208         .pg_class = "nfs",                              /* authentication class */
 209         .pg_stats = &nfs4_callback_stats,
 210         .pg_authenticate = nfs_callback_authenticate,
 211 };