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 }; 215