xref: /openbmc/linux/fs/lockd/mon.c (revision 22246614)
1 /*
2  * linux/fs/lockd/mon.c
3  *
4  * The kernel statd client.
5  *
6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
7  */
8 
9 #include <linux/types.h>
10 #include <linux/utsname.h>
11 #include <linux/kernel.h>
12 #include <linux/sunrpc/clnt.h>
13 #include <linux/sunrpc/xprtsock.h>
14 #include <linux/sunrpc/svc.h>
15 #include <linux/lockd/lockd.h>
16 #include <linux/lockd/sm_inter.h>
17 
18 
19 #define NLMDBG_FACILITY		NLMDBG_MONITOR
20 
21 #define XDR_ADDRBUF_LEN		(20)
22 
23 static struct rpc_clnt *	nsm_create(void);
24 
25 static struct rpc_program	nsm_program;
26 
27 /*
28  * Local NSM state
29  */
30 int				nsm_local_state;
31 
32 /*
33  * Common procedure for SM_MON/SM_UNMON calls
34  */
35 static int
36 nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res)
37 {
38 	struct rpc_clnt	*clnt;
39 	int		status;
40 	struct nsm_args	args;
41 	struct rpc_message msg = {
42 		.rpc_argp	= &args,
43 		.rpc_resp	= res,
44 	};
45 
46 	clnt = nsm_create();
47 	if (IS_ERR(clnt)) {
48 		status = PTR_ERR(clnt);
49 		goto out;
50 	}
51 
52 	memset(&args, 0, sizeof(args));
53 	args.mon_name = nsm->sm_name;
54 	args.addr = nsm->sm_addr.sin_addr.s_addr;
55 	args.prog = NLM_PROGRAM;
56 	args.vers = 3;
57 	args.proc = NLMPROC_NSM_NOTIFY;
58 	memset(res, 0, sizeof(*res));
59 
60 	msg.rpc_proc = &clnt->cl_procinfo[proc];
61 	status = rpc_call_sync(clnt, &msg, 0);
62 	if (status < 0)
63 		printk(KERN_DEBUG "nsm_mon_unmon: rpc failed, status=%d\n",
64 			status);
65 	else
66 		status = 0;
67 	rpc_shutdown_client(clnt);
68  out:
69 	return status;
70 }
71 
72 /*
73  * Set up monitoring of a remote host
74  */
75 int
76 nsm_monitor(struct nlm_host *host)
77 {
78 	struct nsm_handle *nsm = host->h_nsmhandle;
79 	struct nsm_res	res;
80 	int		status;
81 
82 	dprintk("lockd: nsm_monitor(%s)\n", host->h_name);
83 	BUG_ON(nsm == NULL);
84 
85 	if (nsm->sm_monitored)
86 		return 0;
87 
88 	status = nsm_mon_unmon(nsm, SM_MON, &res);
89 
90 	if (status < 0 || res.status != 0)
91 		printk(KERN_NOTICE "lockd: cannot monitor %s\n", host->h_name);
92 	else
93 		nsm->sm_monitored = 1;
94 	return status;
95 }
96 
97 /*
98  * Cease to monitor remote host
99  */
100 int
101 nsm_unmonitor(struct nlm_host *host)
102 {
103 	struct nsm_handle *nsm = host->h_nsmhandle;
104 	struct nsm_res	res;
105 	int		status = 0;
106 
107 	if (nsm == NULL)
108 		return 0;
109 	host->h_nsmhandle = NULL;
110 
111 	if (atomic_read(&nsm->sm_count) == 1
112 	 && nsm->sm_monitored && !nsm->sm_sticky) {
113 		dprintk("lockd: nsm_unmonitor(%s)\n", host->h_name);
114 
115 		status = nsm_mon_unmon(nsm, SM_UNMON, &res);
116 		if (status < 0)
117 			printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
118 					host->h_name);
119 		else
120 			nsm->sm_monitored = 0;
121 	}
122 	nsm_release(nsm);
123 	return status;
124 }
125 
126 /*
127  * Create NSM client for the local host
128  */
129 static struct rpc_clnt *
130 nsm_create(void)
131 {
132 	struct sockaddr_in	sin = {
133 		.sin_family	= AF_INET,
134 		.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
135 		.sin_port	= 0,
136 	};
137 	struct rpc_create_args args = {
138 		.protocol	= XPRT_TRANSPORT_UDP,
139 		.address	= (struct sockaddr *)&sin,
140 		.addrsize	= sizeof(sin),
141 		.servername	= "localhost",
142 		.program	= &nsm_program,
143 		.version	= SM_VERSION,
144 		.authflavor	= RPC_AUTH_NULL,
145 	};
146 
147 	return rpc_create(&args);
148 }
149 
150 /*
151  * XDR functions for NSM.
152  *
153  * See http://www.opengroup.org/ for details on the Network
154  * Status Monitor wire protocol.
155  */
156 
157 static __be32 *xdr_encode_nsm_string(__be32 *p, char *string)
158 {
159 	size_t len = strlen(string);
160 
161 	if (len > SM_MAXSTRLEN)
162 		len = SM_MAXSTRLEN;
163 	return xdr_encode_opaque(p, string, len);
164 }
165 
166 /*
167  * "mon_name" specifies the host to be monitored.
168  *
169  * Linux uses a text version of the IP address of the remote
170  * host as the host identifier (the "mon_name" argument).
171  *
172  * Linux statd always looks up the canonical hostname first for
173  * whatever remote hostname it receives, so this works alright.
174  */
175 static __be32 *xdr_encode_mon_name(__be32 *p, struct nsm_args *argp)
176 {
177 	char	buffer[XDR_ADDRBUF_LEN + 1];
178 	char	*name = argp->mon_name;
179 
180 	if (!nsm_use_hostnames) {
181 		snprintf(buffer, XDR_ADDRBUF_LEN,
182 			 NIPQUAD_FMT, NIPQUAD(argp->addr));
183 		name = buffer;
184 	}
185 
186 	return xdr_encode_nsm_string(p, name);
187 }
188 
189 /*
190  * The "my_id" argument specifies the hostname and RPC procedure
191  * to be called when the status manager receives notification
192  * (via the SM_NOTIFY call) that the state of host "mon_name"
193  * has changed.
194  */
195 static __be32 *xdr_encode_my_id(__be32 *p, struct nsm_args *argp)
196 {
197 	p = xdr_encode_nsm_string(p, utsname()->nodename);
198 	if (!p)
199 		return ERR_PTR(-EIO);
200 
201 	*p++ = htonl(argp->prog);
202 	*p++ = htonl(argp->vers);
203 	*p++ = htonl(argp->proc);
204 
205 	return p;
206 }
207 
208 /*
209  * The "mon_id" argument specifies the non-private arguments
210  * of an SM_MON or SM_UNMON call.
211  */
212 static __be32 *xdr_encode_mon_id(__be32 *p, struct nsm_args *argp)
213 {
214 	p = xdr_encode_mon_name(p, argp);
215 	if (!p)
216 		return ERR_PTR(-EIO);
217 
218 	return xdr_encode_my_id(p, argp);
219 }
220 
221 /*
222  * The "priv" argument may contain private information required
223  * by the SM_MON call. This information will be supplied in the
224  * SM_NOTIFY call.
225  *
226  * Linux provides the raw IP address of the monitored host,
227  * left in network byte order.
228  */
229 static __be32 *xdr_encode_priv(__be32 *p, struct nsm_args *argp)
230 {
231 	*p++ = argp->addr;
232 	*p++ = 0;
233 	*p++ = 0;
234 	*p++ = 0;
235 
236 	return p;
237 }
238 
239 static int
240 xdr_encode_mon(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
241 {
242 	p = xdr_encode_mon_id(p, argp);
243 	if (IS_ERR(p))
244 		return PTR_ERR(p);
245 
246 	p = xdr_encode_priv(p, argp);
247 	if (IS_ERR(p))
248 		return PTR_ERR(p);
249 
250 	rqstp->rq_slen = xdr_adjust_iovec(rqstp->rq_svec, p);
251 	return 0;
252 }
253 
254 static int
255 xdr_encode_unmon(struct rpc_rqst *rqstp, __be32 *p, struct nsm_args *argp)
256 {
257 	p = xdr_encode_mon_id(p, argp);
258 	if (IS_ERR(p))
259 		return PTR_ERR(p);
260 	rqstp->rq_slen = xdr_adjust_iovec(rqstp->rq_svec, p);
261 	return 0;
262 }
263 
264 static int
265 xdr_decode_stat_res(struct rpc_rqst *rqstp, __be32 *p, struct nsm_res *resp)
266 {
267 	resp->status = ntohl(*p++);
268 	resp->state = ntohl(*p++);
269 	dprintk("nsm: xdr_decode_stat_res status %d state %d\n",
270 			resp->status, resp->state);
271 	return 0;
272 }
273 
274 static int
275 xdr_decode_stat(struct rpc_rqst *rqstp, __be32 *p, struct nsm_res *resp)
276 {
277 	resp->state = ntohl(*p++);
278 	return 0;
279 }
280 
281 #define SM_my_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
282 #define SM_my_id_sz	(SM_my_name_sz+3)
283 #define SM_mon_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
284 #define SM_mon_id_sz	(SM_mon_name_sz+SM_my_id_sz)
285 #define SM_priv_sz	(XDR_QUADLEN(SM_PRIV_SIZE))
286 #define SM_mon_sz	(SM_mon_id_sz+SM_priv_sz)
287 #define SM_monres_sz	2
288 #define SM_unmonres_sz	1
289 
290 static struct rpc_procinfo	nsm_procedures[] = {
291 [SM_MON] = {
292 		.p_proc		= SM_MON,
293 		.p_encode	= (kxdrproc_t) xdr_encode_mon,
294 		.p_decode	= (kxdrproc_t) xdr_decode_stat_res,
295 		.p_arglen	= SM_mon_sz,
296 		.p_replen	= SM_monres_sz,
297 		.p_statidx	= SM_MON,
298 		.p_name		= "MONITOR",
299 	},
300 [SM_UNMON] = {
301 		.p_proc		= SM_UNMON,
302 		.p_encode	= (kxdrproc_t) xdr_encode_unmon,
303 		.p_decode	= (kxdrproc_t) xdr_decode_stat,
304 		.p_arglen	= SM_mon_id_sz,
305 		.p_replen	= SM_unmonres_sz,
306 		.p_statidx	= SM_UNMON,
307 		.p_name		= "UNMONITOR",
308 	},
309 };
310 
311 static struct rpc_version	nsm_version1 = {
312 		.number		= 1,
313 		.nrprocs	= ARRAY_SIZE(nsm_procedures),
314 		.procs		= nsm_procedures
315 };
316 
317 static struct rpc_version *	nsm_version[] = {
318 	[1] = &nsm_version1,
319 };
320 
321 static struct rpc_stat		nsm_stats;
322 
323 static struct rpc_program	nsm_program = {
324 		.name		= "statd",
325 		.number		= SM_PROGRAM,
326 		.nrvers		= ARRAY_SIZE(nsm_version),
327 		.version	= nsm_version,
328 		.stats		= &nsm_stats
329 };
330