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 /* 44 * If the kernel has IPv6 support available, always listen for 45 * both AF_INET and AF_INET6 requests. 46 */ 47 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 48 static const sa_family_t nfs_callback_family = AF_INET6; 49 #else 50 static const sa_family_t nfs_callback_family = AF_INET; 51 #endif 52 53 static int param_set_port(const char *val, struct kernel_param *kp) 54 { 55 char *endp; 56 int num = simple_strtol(val, &endp, 0); 57 if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max) 58 return -EINVAL; 59 *((int *)kp->arg) = num; 60 return 0; 61 } 62 63 module_param_call(callback_tcpport, param_set_port, param_get_int, 64 &nfs_callback_set_tcpport, 0644); 65 66 /* 67 * This is the callback kernel thread. 68 */ 69 static int 70 nfs_callback_svc(void *vrqstp) 71 { 72 int err, preverr = 0; 73 struct svc_rqst *rqstp = vrqstp; 74 75 set_freezable(); 76 77 /* 78 * FIXME: do we really need to run this under the BKL? If so, please 79 * add a comment about what it's intended to protect. 80 */ 81 lock_kernel(); 82 while (!kthread_should_stop()) { 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 preverr = err; 89 continue; 90 } 91 if (err < 0) { 92 if (err != preverr) { 93 printk(KERN_WARNING "%s: unexpected error " 94 "from svc_recv (%d)\n", __func__, err); 95 preverr = err; 96 } 97 schedule_timeout_uninterruptible(HZ); 98 continue; 99 } 100 preverr = err; 101 svc_process(rqstp); 102 } 103 unlock_kernel(); 104 return 0; 105 } 106 107 /* 108 * Bring up the callback thread if it is not already up. 109 */ 110 int nfs_callback_up(void) 111 { 112 struct svc_serv *serv = NULL; 113 int ret = 0; 114 115 mutex_lock(&nfs_callback_mutex); 116 if (nfs_callback_info.users++ || nfs_callback_info.task != NULL) 117 goto out; 118 serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, 119 nfs_callback_family, NULL); 120 ret = -ENOMEM; 121 if (!serv) 122 goto out_err; 123 124 ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport, 125 SVC_SOCK_ANONYMOUS); 126 if (ret <= 0) 127 goto out_err; 128 nfs_callback_tcpport = ret; 129 dprintk("NFS: Callback listener port = %u (af %u)\n", 130 nfs_callback_tcpport, nfs_callback_family); 131 132 nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]); 133 if (IS_ERR(nfs_callback_info.rqst)) { 134 ret = PTR_ERR(nfs_callback_info.rqst); 135 nfs_callback_info.rqst = NULL; 136 goto out_err; 137 } 138 139 svc_sock_update_bufs(serv); 140 141 nfs_callback_info.task = kthread_run(nfs_callback_svc, 142 nfs_callback_info.rqst, 143 "nfsv4-svc"); 144 if (IS_ERR(nfs_callback_info.task)) { 145 ret = PTR_ERR(nfs_callback_info.task); 146 svc_exit_thread(nfs_callback_info.rqst); 147 nfs_callback_info.rqst = NULL; 148 nfs_callback_info.task = NULL; 149 goto out_err; 150 } 151 out: 152 /* 153 * svc_create creates the svc_serv with sv_nrthreads == 1, and then 154 * svc_prepare_thread increments that. So we need to call svc_destroy 155 * on both success and failure so that the refcount is 1 when the 156 * thread exits. 157 */ 158 if (serv) 159 svc_destroy(serv); 160 mutex_unlock(&nfs_callback_mutex); 161 return ret; 162 out_err: 163 dprintk("NFS: Couldn't create callback socket or server thread; " 164 "err = %d\n", ret); 165 nfs_callback_info.users--; 166 goto out; 167 } 168 169 /* 170 * Kill the callback thread if it's no longer being used. 171 */ 172 void nfs_callback_down(void) 173 { 174 mutex_lock(&nfs_callback_mutex); 175 nfs_callback_info.users--; 176 if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) { 177 kthread_stop(nfs_callback_info.task); 178 svc_exit_thread(nfs_callback_info.rqst); 179 nfs_callback_info.rqst = NULL; 180 nfs_callback_info.task = NULL; 181 } 182 mutex_unlock(&nfs_callback_mutex); 183 } 184 185 static int nfs_callback_authenticate(struct svc_rqst *rqstp) 186 { 187 struct nfs_client *clp; 188 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]); 189 190 /* Don't talk to strangers */ 191 clp = nfs_find_client(svc_addr(rqstp), 4); 192 if (clp == NULL) 193 return SVC_DROP; 194 195 dprintk("%s: %s NFSv4 callback!\n", __func__, 196 svc_print_addr(rqstp, buf, sizeof(buf))); 197 nfs_put_client(clp); 198 199 switch (rqstp->rq_authop->flavour) { 200 case RPC_AUTH_NULL: 201 if (rqstp->rq_proc != CB_NULL) 202 return SVC_DENIED; 203 break; 204 case RPC_AUTH_UNIX: 205 break; 206 case RPC_AUTH_GSS: 207 /* FIXME: RPCSEC_GSS handling? */ 208 default: 209 return SVC_DENIED; 210 } 211 return SVC_OK; 212 } 213 214 /* 215 * Define NFS4 callback program 216 */ 217 static struct svc_version *nfs4_callback_version[] = { 218 [1] = &nfs4_callback_version1, 219 }; 220 221 static struct svc_stat nfs4_callback_stats; 222 223 static struct svc_program nfs4_callback_program = { 224 .pg_prog = NFS4_CALLBACK, /* RPC service number */ 225 .pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */ 226 .pg_vers = nfs4_callback_version, /* version table */ 227 .pg_name = "NFSv4 callback", /* service name */ 228 .pg_class = "nfs", /* authentication class */ 229 .pg_stats = &nfs4_callback_stats, 230 .pg_authenticate = nfs_callback_authenticate, 231 }; 232