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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 #include <linux/freezer.h>
  18
  19 #include <net/inet_sock.h>
  20
  21 #include "nfs4_fs.h"
  22 #include "callback.h"
  23 #include "internal.h"
  24
  25 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  26
  27 struct nfs_callback_data {
  28         unsigned int users;
  29         struct svc_serv *serv;
  30         pid_t pid;
  31         struct completion started;
  32         struct completion stopped;
  33 };
  34
  35 static struct nfs_callback_data nfs_callback_info;
  36 static DEFINE_MUTEX(nfs_callback_mutex);
  37 static struct svc_program nfs4_callback_program;
  38
  39 unsigned int nfs_callback_set_tcpport;
  40 unsigned short nfs_callback_tcpport;
  41 static const int nfs_set_port_min = 0;
  42 static const int nfs_set_port_max = 65535;
  43
  44 static int param_set_port(const char *val, struct kernel_param *kp)
  45 {
  46         char *endp;
  47         int num = simple_strtol(val, &endp, 0);
  48         if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
  49                 return -EINVAL;
  50         *((int *)kp->arg) = num;
  51         return 0;
  52 }
  53
  54 module_param_call(callback_tcpport, param_set_port, param_get_int,
  55                  &nfs_callback_set_tcpport, 0644);
  56
  57 /*
  58  * This is the callback kernel thread.
  59  */
  60 static void nfs_callback_svc(struct svc_rqst *rqstp)
  61 {
  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         set_freezable();
  72
  73         complete(&nfs_callback_info.started);
  74
  75         for(;;) {
  76                 char buf[RPC_MAX_ADDRBUFLEN];
  77
  78                 if (signalled()) {
  79                         if (nfs_callback_info.users == 0)
  80                                 break;
  81                         flush_signals(current);
  82                 }
  83                 /*
  84                  * Listen for a request on the socket
  85                  */
  86                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
  87                 if (err == -EAGAIN || err == -EINTR)
  88                         continue;
  89                 if (err < 0) {
  90                         printk(KERN_WARNING
  91                                         "%s: terminating on error %d\n",
  92                                         __FUNCTION__, -err);
  93                         break;
  94                 }
  95                 dprintk("%s: request from %s\n", __FUNCTION__,
  96                                 svc_print_addr(rqstp, buf, sizeof(buf)));
  97                 svc_process(rqstp);
  98         }
  99
 100         svc_exit_thread(rqstp);
 101         nfs_callback_info.pid = 0;
 102         complete(&nfs_callback_info.stopped);
 103         unlock_kernel();
 104         module_put_and_exit(0);
 105 }
 106
 107 /*
 108  * Bring up the server process if it is not already up.
 109  */
 110 int nfs_callback_up(void)
 111 {
 112         struct svc_serv *serv;
 113         int ret = 0;
 114
 115         lock_kernel();
 116         mutex_lock(&nfs_callback_mutex);
 117         if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
 118                 goto out;
 119         init_completion(&nfs_callback_info.started);
 120         init_completion(&nfs_callback_info.stopped);
 121         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 122         ret = -ENOMEM;
 123         if (!serv)
 124                 goto out_err;
 125
 126         ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport,
 127                                                         SVC_SOCK_ANONYMOUS);
 128         if (ret <= 0)
 129                 goto out_destroy;
 130         nfs_callback_tcpport = ret;
 131         dprintk("Callback port = 0x%x\n", nfs_callback_tcpport);
 132
 133         ret = svc_create_thread(nfs_callback_svc, serv);
 134         if (ret < 0)
 135                 goto out_destroy;
 136         nfs_callback_info.serv = serv;
 137         wait_for_completion(&nfs_callback_info.started);
 138 out:
 139         mutex_unlock(&nfs_callback_mutex);
 140         unlock_kernel();
 141         return ret;
 142 out_destroy:
 143         dprintk("Couldn't create callback socket or server thread; err = %d\n",
 144                 ret);
 145         svc_destroy(serv);
 146 out_err:
 147         nfs_callback_info.users--;
 148         goto out;
 149 }
 150
 151 /*
 152  * Kill the server process if it is not already up.
 153  */
 154 void nfs_callback_down(void)
 155 {
 156         lock_kernel();
 157         mutex_lock(&nfs_callback_mutex);
 158         nfs_callback_info.users--;
 159         do {
 160                 if (nfs_callback_info.users != 0 || nfs_callback_info.pid == 0)
 161                         break;
 162                 if (kill_proc(nfs_callback_info.pid, SIGKILL, 1) < 0)
 163                         break;
 164         } while (wait_for_completion_timeout(&nfs_callback_info.stopped, 5*HZ) == 0);
 165         mutex_unlock(&nfs_callback_mutex);
 166         unlock_kernel();
 167 }
 168
 169 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
 170 {
 171         struct sockaddr_in *addr = svc_addr_in(rqstp);
 172         struct nfs_client *clp;
 173         char buf[RPC_MAX_ADDRBUFLEN];
 174
 175         /* Don't talk to strangers */
 176         clp = nfs_find_client(addr, 4);
 177         if (clp == NULL)
 178                 return SVC_DROP;
 179
 180         dprintk("%s: %s NFSv4 callback!\n", __FUNCTION__,
 181                         svc_print_addr(rqstp, buf, sizeof(buf)));
 182         nfs_put_client(clp);
 183
 184         switch (rqstp->rq_authop->flavour) {
 185                 case RPC_AUTH_NULL:
 186                         if (rqstp->rq_proc != CB_NULL)
 187                                 return SVC_DENIED;
 188                         break;
 189                 case RPC_AUTH_UNIX:
 190                         break;
 191                 case RPC_AUTH_GSS:
 192                         /* FIXME: RPCSEC_GSS handling? */
 193                 default:
 194                         return SVC_DENIED;
 195         }
 196         return SVC_OK;
 197 }
 198
 199 /*
 200  * Define NFS4 callback program
 201  */
 202 static struct svc_version *nfs4_callback_version[] = {
 203         [1] = &nfs4_callback_version1,
 204 };
 205
 206 static struct svc_stat nfs4_callback_stats;
 207
 208 static struct svc_program nfs4_callback_program = {
 209         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
 210         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
 211         .pg_vers = nfs4_callback_version,               /* version table */
 212         .pg_name = "NFSv4 callback",                    /* service name */
 213         .pg_class = "nfs",                              /* authentication class */
 214         .pg_stats = &nfs4_callback_stats,
 215         .pg_authenticate = nfs_callback_authenticate,
 216 };