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_rqst *rqst; 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 return 0; 95 } 96 97 /* 98 * Bring up the callback thread if it is not already up. 99 */ 100 int nfs_callback_up(void) 101 { 102 struct svc_serv *serv = NULL; 103 int ret = 0; 104 105 mutex_lock(&nfs_callback_mutex); 106 if (nfs_callback_info.users++ || nfs_callback_info.task != NULL) 107 goto out; 108 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, 109 AF_INET, NULL); 110 ret = -ENOMEM; 111 if (!serv) 112 goto out_err; 113 114 ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport, 115 SVC_SOCK_ANONYMOUS); 116 if (ret <= 0) 117 goto out_err; 118 nfs_callback_tcpport = ret; 119 dprintk("Callback port = 0x%x\n", nfs_callback_tcpport); 120 121 nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]); 122 if (IS_ERR(nfs_callback_info.rqst)) { 123 ret = PTR_ERR(nfs_callback_info.rqst); 124 nfs_callback_info.rqst = NULL; 125 goto out_err; 126 } 127 128 svc_sock_update_bufs(serv); 129 130 nfs_callback_info.task = kthread_run(nfs_callback_svc, 131 nfs_callback_info.rqst, 132 "nfsv4-svc"); 133 if (IS_ERR(nfs_callback_info.task)) { 134 ret = PTR_ERR(nfs_callback_info.task); 135 svc_exit_thread(nfs_callback_info.rqst); 136 nfs_callback_info.rqst = NULL; 137 nfs_callback_info.task = NULL; 138 goto out_err; 139 } 140 out: 141 /* 142 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 143 * svc_prepare_thread increments that. So we need to call svc_destroy 144 * on both success and failure so that the refcount is 1 when the 145 * thread exits. 146 */ 147 if (serv) 148 svc_destroy(serv); 149 mutex_unlock(&nfs_callback_mutex); 150 return ret; 151 out_err: 152 dprintk("Couldn't create callback socket or server thread; err = %d\n", 153 ret); 154 nfs_callback_info.users--; 155 goto out; 156 } 157 158 /* 159 * Kill the callback thread if it's no longer being used. 160 */ 161 void nfs_callback_down(void) 162 { 163 mutex_lock(&nfs_callback_mutex); 164 nfs_callback_info.users--; 165 if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) { 166 kthread_stop(nfs_callback_info.task); 167 svc_exit_thread(nfs_callback_info.rqst); 168 nfs_callback_info.rqst = NULL; 169 nfs_callback_info.task = NULL; 170 } 171 mutex_unlock(&nfs_callback_mutex); 172 } 173 174 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 175 { 176 struct nfs_client *clp; 177 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 178 179 /* Don't talk to strangers */ 180 clp = nfs_find_client(svc_addr(rqstp), 4); 181 if (clp == NULL) 182 return SVC_DROP; 183 184 dprintk("%s: %s NFSv4 callback!\n", __func__, 185 svc_print_addr(rqstp, buf, sizeof(buf))); 186 nfs_put_client(clp); 187 188 switch (rqstp->rq_authop->flavour) { 189 case RPC_AUTH_NULL: 190 if (rqstp->rq_proc != CB_NULL) 191 return SVC_DENIED; 192 break; 193 case RPC_AUTH_UNIX: 194 break; 195 case RPC_AUTH_GSS: 196 /* FIXME: RPCSEC_GSS handling? */ 197 default: 198 return SVC_DENIED; 199 } 200 return SVC_OK; 201 } 202 203 /* 204 * Define NFS4 callback program 205 */ 206 static struct svc_version *nfs4_callback_version[] = { 207 [1] = &nfs4_callback_version1, 208 }; 209 210 static struct svc_stat nfs4_callback_stats; 211 212 static struct svc_program nfs4_callback_program = { 213 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 214 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 215 .pg_vers = nfs4_callback_version, /* version table */ 216 .pg_name = "NFSv4 callback", /* service name */ 217 .pg_class = "nfs", /* authentication class */ 218 .pg_stats = &nfs4_callback_stats, 219 .pg_authenticate = nfs_callback_authenticate, 220 }; 221