xref: /openbmc/linux/fs/nfs/callback.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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