xref: /openbmc/linux/fs/nfs/callback.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * linux/fs/nfs/callback.c
3  *
4  * Copyright (C) 2004 Trond Myklebust
5  *
6  * NFSv4 callback handling
7  */
8 
9 #include <linux/config.h>
10 #include <linux/completion.h>
11 #include <linux/ip.h>
12 #include <linux/module.h>
13 #include <linux/smp_lock.h>
14 #include <linux/sunrpc/svc.h>
15 #include <linux/sunrpc/svcsock.h>
16 #include <linux/nfs_fs.h>
17 #include "nfs4_fs.h"
18 #include "callback.h"
19 
20 #define NFSDBG_FACILITY NFSDBG_CALLBACK
21 
22 struct nfs_callback_data {
23 	unsigned int users;
24 	struct svc_serv *serv;
25 	pid_t pid;
26 	struct completion started;
27 	struct completion stopped;
28 };
29 
30 static struct nfs_callback_data nfs_callback_info;
31 static DECLARE_MUTEX(nfs_callback_sema);
32 static struct svc_program nfs4_callback_program;
33 
34 unsigned short nfs_callback_tcpport;
35 
36 /*
37  * This is the callback kernel thread.
38  */
39 static void nfs_callback_svc(struct svc_rqst *rqstp)
40 {
41 	struct svc_serv *serv = rqstp->rq_server;
42 	int err;
43 
44 	__module_get(THIS_MODULE);
45 	lock_kernel();
46 
47 	nfs_callback_info.pid = current->pid;
48 	daemonize("nfsv4-svc");
49 	/* Process request with signals blocked, but allow SIGKILL.  */
50 	allow_signal(SIGKILL);
51 
52 	complete(&nfs_callback_info.started);
53 
54 	while (nfs_callback_info.users != 0 || !signalled()) {
55 		/*
56 		 * Listen for a request on the socket
57 		 */
58 		err = svc_recv(serv, rqstp, MAX_SCHEDULE_TIMEOUT);
59 		if (err == -EAGAIN || err == -EINTR)
60 			continue;
61 		if (err < 0) {
62 			printk(KERN_WARNING
63 					"%s: terminating on error %d\n",
64 					__FUNCTION__, -err);
65 			break;
66 		}
67 		dprintk("%s: request from %u.%u.%u.%u\n", __FUNCTION__,
68 				NIPQUAD(rqstp->rq_addr.sin_addr.s_addr));
69 		svc_process(serv, rqstp);
70 	}
71 
72 	nfs_callback_info.pid = 0;
73 	complete(&nfs_callback_info.stopped);
74 	unlock_kernel();
75 	module_put_and_exit(0);
76 }
77 
78 /*
79  * Bring up the server process if it is not already up.
80  */
81 int nfs_callback_up(void)
82 {
83 	struct svc_serv *serv;
84 	struct svc_sock *svsk;
85 	int ret = 0;
86 
87 	lock_kernel();
88 	down(&nfs_callback_sema);
89 	if (nfs_callback_info.users++ || nfs_callback_info.pid != 0)
90 		goto out;
91 	init_completion(&nfs_callback_info.started);
92 	init_completion(&nfs_callback_info.stopped);
93 	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE);
94 	ret = -ENOMEM;
95 	if (!serv)
96 		goto out_err;
97 	/* FIXME: We don't want to register this socket with the portmapper */
98 	ret = svc_makesock(serv, IPPROTO_TCP, 0);
99 	if (ret < 0)
100 		goto out_destroy;
101 	if (!list_empty(&serv->sv_permsocks)) {
102 		svsk = list_entry(serv->sv_permsocks.next,
103 				struct svc_sock, sk_list);
104 		nfs_callback_tcpport = ntohs(inet_sk(svsk->sk_sk)->sport);
105 		dprintk ("Callback port = 0x%x\n", nfs_callback_tcpport);
106 	} else
107 		BUG();
108 	ret = svc_create_thread(nfs_callback_svc, serv);
109 	if (ret < 0)
110 		goto out_destroy;
111 	nfs_callback_info.serv = serv;
112 	wait_for_completion(&nfs_callback_info.started);
113 out:
114 	up(&nfs_callback_sema);
115 	unlock_kernel();
116 	return ret;
117 out_destroy:
118 	svc_destroy(serv);
119 out_err:
120 	nfs_callback_info.users--;
121 	goto out;
122 }
123 
124 /*
125  * Kill the server process if it is not already up.
126  */
127 int nfs_callback_down(void)
128 {
129 	int ret = 0;
130 
131 	lock_kernel();
132 	down(&nfs_callback_sema);
133 	if (--nfs_callback_info.users || nfs_callback_info.pid == 0)
134 		goto out;
135 	kill_proc(nfs_callback_info.pid, SIGKILL, 1);
136 	wait_for_completion(&nfs_callback_info.stopped);
137 out:
138 	up(&nfs_callback_sema);
139 	unlock_kernel();
140 	return ret;
141 }
142 
143 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
144 {
145 	struct in_addr *addr = &rqstp->rq_addr.sin_addr;
146 	struct nfs4_client *clp;
147 
148 	/* Don't talk to strangers */
149 	clp = nfs4_find_client(addr);
150 	if (clp == NULL)
151 		return SVC_DROP;
152 	dprintk("%s: %u.%u.%u.%u NFSv4 callback!\n", __FUNCTION__, NIPQUAD(addr));
153 	nfs4_put_client(clp);
154 	switch (rqstp->rq_authop->flavour) {
155 		case RPC_AUTH_NULL:
156 			if (rqstp->rq_proc != CB_NULL)
157 				return SVC_DENIED;
158 			break;
159 		case RPC_AUTH_UNIX:
160 			break;
161 		case RPC_AUTH_GSS:
162 			/* FIXME: RPCSEC_GSS handling? */
163 		default:
164 			return SVC_DENIED;
165 	}
166 	return SVC_OK;
167 }
168 
169 /*
170  * Define NFS4 callback program
171  */
172 extern struct svc_version nfs4_callback_version1;
173 
174 static struct svc_version *nfs4_callback_version[] = {
175 	[1] = &nfs4_callback_version1,
176 };
177 
178 static struct svc_stat nfs4_callback_stats;
179 
180 static struct svc_program nfs4_callback_program = {
181 	.pg_prog = NFS4_CALLBACK,			/* RPC service number */
182 	.pg_nvers = ARRAY_SIZE(nfs4_callback_version),	/* Number of entries */
183 	.pg_vers = nfs4_callback_version,		/* version table */
184 	.pg_name = "NFSv4 callback",			/* service name */
185 	.pg_class = "nfs",				/* authentication class */
186 	.pg_stats = &nfs4_callback_stats,
187 	.pg_authenticate = nfs_callback_authenticate,
188 };
189