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 #include <linux/kthread.h> 19 20 #include <net/inet_sock.h> 21 22 #include "nfs4_fs.h" 23 #include "callback.h" 24 #include "internal.h" 25 26 #define NFSDBG_FACILITY NFSDBG_CALLBACK 27 28 struct nfs_callback_data { 29 unsigned int users; 30 struct svc_serv *serv; 31 struct task_struct *task; 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 int 60 nfs_callback_svc(void *vrqstp) 61 { 62 int err, preverr = 0; 63 struct svc_rqst *rqstp = vrqstp; 64 65 set_freezable(); 66 67 /* 68 * FIXME: do we really need to run this under the BKL? If so, please 69 * add a comment about what it's intended to protect. 70 */ 71 lock_kernel(); 72 while (!kthread_should_stop()) { 73 /* 74 * Listen for a request on the socket 75 */ 76 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT); 77 if (err == -EAGAIN || err == -EINTR) { 78 preverr = err; 79 continue; 80 } 81 if (err < 0) { 82 if (err != preverr) { 83 printk(KERN_WARNING "%s: unexpected error " 84 "from svc_recv (%d)\n", __func__, err); 85 preverr = err; 86 } 87 schedule_timeout_uninterruptible(HZ); 88 continue; 89 } 90 preverr = err; 91 svc_process(rqstp); 92 } 93 unlock_kernel(); 94 nfs_callback_info.task = NULL; 95 svc_exit_thread(rqstp); 96 return 0; 97 } 98 99 /* 100 * Bring up the server process if it is not already up. 101 */ 102 int nfs_callback_up(void) 103 { 104 struct svc_serv *serv = NULL; 105 struct svc_rqst *rqstp; 106 int ret = 0; 107 108 lock_kernel(); 109 mutex_lock(&nfs_callback_mutex); 110 if (nfs_callback_info.users++ || nfs_callback_info.task != NULL) 111 goto out; 112 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL); 113 ret = -ENOMEM; 114 if (!serv) 115 goto out_err; 116 117 ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport, 118 SVC_SOCK_ANONYMOUS); 119 if (ret <= 0) 120 goto out_err; 121 nfs_callback_tcpport = ret; 122 dprintk("Callback port = 0x%x\n", nfs_callback_tcpport); 123 124 rqstp = svc_prepare_thread(serv, &serv->sv_pools[0]); 125 if (IS_ERR(rqstp)) { 126 ret = PTR_ERR(rqstp); 127 goto out_err; 128 } 129 130 svc_sock_update_bufs(serv); 131 nfs_callback_info.serv = serv; 132 133 nfs_callback_info.task = kthread_run(nfs_callback_svc, rqstp, 134 "nfsv4-svc"); 135 if (IS_ERR(nfs_callback_info.task)) { 136 ret = PTR_ERR(nfs_callback_info.task); 137 nfs_callback_info.serv = NULL; 138 nfs_callback_info.task = NULL; 139 svc_exit_thread(rqstp); 140 goto out_err; 141 } 142 out: 143 /* 144 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 145 * svc_prepare_thread increments that. So we need to call svc_destroy 146 * on both success and failure so that the refcount is 1 when the 147 * thread exits. 148 */ 149 if (serv) 150 svc_destroy(serv); 151 mutex_unlock(&nfs_callback_mutex); 152 unlock_kernel(); 153 return ret; 154 out_err: 155 dprintk("Couldn't create callback socket or server thread; err = %d\n", 156 ret); 157 nfs_callback_info.users--; 158 goto out; 159 } 160 161 /* 162 * Kill the server process if it is not already down. 163 */ 164 void nfs_callback_down(void) 165 { 166 lock_kernel(); 167 mutex_lock(&nfs_callback_mutex); 168 nfs_callback_info.users--; 169 if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) 170 kthread_stop(nfs_callback_info.task); 171 mutex_unlock(&nfs_callback_mutex); 172 unlock_kernel(); 173 } 174 175 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 176 { 177 struct nfs_client *clp; 178 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 179 180 /* Don't talk to strangers */ 181 clp = nfs_find_client(svc_addr(rqstp), 4); 182 if (clp == NULL) 183 return SVC_DROP; 184 185 dprintk("%s: %s NFSv4 callback!\n", __func__, 186 svc_print_addr(rqstp, buf, sizeof(buf))); 187 nfs_put_client(clp); 188 189 switch (rqstp->rq_authop->flavour) { 190 case RPC_AUTH_NULL: 191 if (rqstp->rq_proc != CB_NULL) 192 return SVC_DENIED; 193 break; 194 case RPC_AUTH_UNIX: 195 break; 196 case RPC_AUTH_GSS: 197 /* FIXME: RPCSEC_GSS handling? */ 198 default: 199 return SVC_DENIED; 200 } 201 return SVC_OK; 202 } 203 204 /* 205 * Define NFS4 callback program 206 */ 207 static struct svc_version *nfs4_callback_version[] = { 208 [1] = &nfs4_callback_version1, 209 }; 210 211 static struct svc_stat nfs4_callback_stats; 212 213 static struct svc_program nfs4_callback_program = { 214 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 215 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 216 .pg_vers = nfs4_callback_version, /* version table */ 217 .pg_name = "NFSv4 callback", /* service name */ 218 .pg_class = "nfs", /* authentication class */ 219 .pg_stats = &nfs4_callback_stats, 220 .pg_authenticate = nfs_callback_authenticate, 221 }; 222