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 }; 217