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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         int err;
  62
  63         __module_get(THIS_MODULE);
  64         lock_kernel();
  65
  66         nfs_callback_info.pid = current->pid;
  67         daemonize("nfsv4-svc");
  68         /* Process request with signals blocked, but allow SIGKILL.  */
  69         allow_signal(SIGKILL);
  70
  71         complete(&nfs_callback_info.started);
  72
  73         for(;;) {
  74                 char buf[RPC_MAX_ADDRBUFLEN];
  75
  76                 if (signalled()) {
  77                         if (nfs_callback_info.users == 0)
  78                                 break;
  79                         flush_signals(current);
  80                 }
  81                 /*
  82                  * Listen for a request on the socket
  83                  */
  84                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  85                 if (err == -EAGAIN || err == -EINTR)
  86                         continue;
  87                 if (err < 0) {
  88                         printk(KERN_WARNING
  89                                         "%s: terminating on error %d\n",
  90                                         __FUNCTION__, -err);
  91                         break;
  92                 }
  93                 dprintk("%s: request from %s\n", __FUNCTION__,
  94                                 svc_print_addr(rqstp, buf, sizeof(buf)));
  95                 svc_process(rqstp);
  96         }
  97
  98         svc_exit_thread(rqstp);
  99         nfs_callback_info.pid = 0;
 100         complete(&nfs_callback_info.stopped);
 101         unlock_kernel();
 102         module_put_and_exit(0);
 103 }
 104
 105 /*
 106  * Bring up the server process if it is not already up.
 107  */
 108 int nfs_callback_up(void)
 109 {
 110         struct svc_serv *serv;
 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, NULL);
 120         ret = -ENOMEM;
 121         if (!serv)
 122                 goto out_err;
 123
 124         ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport,
 125                                                         SVC_SOCK_ANONYMOUS);
 126         if (ret <= 0)
 127                 goto out_destroy;
 128         nfs_callback_tcpport = ret;
 129         dprintk("Callback port = 0x%x\n", nfs_callback_tcpport);
 130
 131         ret = svc_create_thread(nfs_callback_svc, serv);
 132         if (ret < 0)
 133                 goto out_destroy;
 134         nfs_callback_info.serv = serv;
 135         wait_for_completion(&nfs_callback_info.started);
 136 out:
 137         mutex_unlock(&nfs_callback_mutex);
 138         unlock_kernel();
 139         return ret;
 140 out_destroy:
 141         dprintk("Couldn't create callback socket or server thread; err = %d\n",
 142                 ret);
 143         svc_destroy(serv);
 144 out_err:
 145         nfs_callback_info.users--;
 146         goto out;
 147 }
 148
 149 /*
 150  * Kill the server process if it is not already up.
 151  */
 152 void nfs_callback_down(void)
 153 {
 154         lock_kernel();
 155         mutex_lock(&nfs_callback_mutex);
 156         nfs_callback_info.users--;
 157         do {
 158                 if (nfs_callback_info.users != 0 || nfs_callback_info.pid == 0)
 159                         break;
 160                 if (kill_proc(nfs_callback_info.pid, SIGKILL, 1) < 0)
 161                         break;
 162         } while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0);
 163         mutex_unlock(&nfs_callback_mutex);
 164         unlock_kernel();
 165 }
 166
 167 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 168 {
 169         struct sockaddr_in *addr = svc_addr_in(rqstp);
 170         struct nfs_client *clp;
 171         char buf[RPC_MAX_ADDRBUFLEN];
 172
 173         /* Don't talk to strangers */
 174         clp = nfs_find_client(addr, 4);
 175         if (clp == NULL)
 176                 return SVC_DROP;
 177
 178         dprintk("%s: %s NFSv4 callback!\n", __FUNCTION__,
 179                         svc_print_addr(rqstp, buf, sizeof(buf)));
 180         nfs_put_client(clp);
 181
 182         switch (rqstp->rq_authop->flavour) {
 183                 case RPC_AUTH_NULL:
 184                         if (rqstp->rq_proc != CB_NULL)
 185                                 return SVC_DENIED;
 186                         break;
 187                 case RPC_AUTH_UNIX:
 188                         break;
 189                 case RPC_AUTH_GSS:
 190                         /* FIXME: RPCSEC_GSS handling? */
 191                 default:
 192                         return SVC_DENIED;
 193         }
 194         return SVC_OK;
 195 }
 196
 197 /*
 198  * Define NFS4 callback program
 199  */
 200 static struct svc_version *nfs4_callback_version[] = {
 201         [1] = &nfs4_callback_version1,
 202 };
 203
 204 static struct svc_stat nfs4_callback_stats;
 205
 206 static struct svc_program nfs4_callback_program = {
 207         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 208         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 209         .pg_vers = nfs4_callback_version,               /* version table */
 210         .pg_name = "NFSv4 callback",                    /* service name */
 211         .pg_class = "nfs",                              /* authentication class */
 212         .pg_stats = &nfs4_callback_stats,
 213         .pg_authenticate = nfs_callback_authenticate,
 214 };