1 /*
2 * linux/fs/lockd/host.c
3 *
4 * Management for NLM peer hosts. The nlm_host struct is shared
5 * between client and server implementation. The only reason to
6 * do so is to reduce code bloat.
7 *
8 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
9 */
10
11 #include <linux/types.h>
12 #include <linux/sched.h>
13 #include <linux/slab.h>
14 #include <linux/in.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/sunrpc/svc.h>
17 #include <linux/lockd/lockd.h>
18 #include <linux/lockd/sm_inter.h>
19
20
21 #define NLMDBG_FACILITY NLMDBG_HOSTCACHE
22 #define NLM_HOST_MAX 64
23 #define NLM_HOST_NRHASH 32
24 #define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1))
25 #define NLM_PTRHASH(ptr) ((((u32)(unsigned long) ptr) / 32) & (NLM_HOST_NRHASH-1))
26 #define NLM_HOST_REBIND (60 * HZ)
27 #define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
28 #define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ)
29 #define NLM_HOST_ADDR(sv) (&(sv)->s_nlmclnt->cl_xprt->addr)
30
31 static struct nlm_host * nlm_hosts[NLM_HOST_NRHASH];
32 static unsigned long next_gc;
33 static int nrhosts;
34 static DECLARE_MUTEX(nlm_host_sema);
35
36
37 static void nlm_gc_hosts(void);
38
39 /*
40 * Find an NLM server handle in the cache. If there is none, create it.
41 */
42 struct nlm_host *
nlmclnt_lookup_host(struct sockaddr_in * sin,int proto,int version)43 nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version)
44 {
45 return nlm_lookup_host(NULL, sin, proto, version);
46 }
47
48 /*
49 * Find an NLM client handle in the cache. If there is none, create it.
50 */
51 struct nlm_host *
nlmsvc_lookup_host(struct svc_rqst * rqstp)52 nlmsvc_lookup_host(struct svc_rqst *rqstp)
53 {
54 return nlm_lookup_host(rqstp->rq_client, &rqstp->rq_addr,
55 rqstp->rq_prot, rqstp->rq_vers);
56 }
57
58 /*
59 * Match the given host against client/address
60 */
61 static inline int
nlm_match_host(struct nlm_host * host,struct svc_client * clnt,struct sockaddr_in * sin)62 nlm_match_host(struct nlm_host *host, struct svc_client *clnt,
63 struct sockaddr_in *sin)
64 {
65 if (clnt)
66 return host->h_exportent == clnt;
67 return nlm_cmp_addr(&host->h_addr, sin);
68 }
69
70 /*
71 * Common host lookup routine for server & client
72 */
73 struct nlm_host *
nlm_lookup_host(struct svc_client * clnt,struct sockaddr_in * sin,int proto,int version)74 nlm_lookup_host(struct svc_client *clnt, struct sockaddr_in *sin,
75 int proto, int version)
76 {
77 struct nlm_host *host, **hp;
78 u32 addr;
79 int hash;
80
81 if (!clnt && !sin) {
82 printk(KERN_NOTICE "lockd: no clnt or addr in lookup_host!\n");
83 return NULL;
84 }
85
86 dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
87 (unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
88
89 if (clnt)
90 hash = NLM_PTRHASH(clnt);
91 else
92 hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
93
94 /* Lock hash table */
95 down(&nlm_host_sema);
96
97 if (time_after_eq(jiffies, next_gc))
98 nlm_gc_hosts();
99
100 for (hp = &nlm_hosts[hash]; (host = *hp); hp = &host->h_next) {
101 if (proto && host->h_proto != proto)
102 continue;
103 if (version && host->h_version != version)
104 continue;
105
106 if (nlm_match_host(host, clnt, sin)) {
107 if (hp != nlm_hosts + hash) {
108 *hp = host->h_next;
109 host->h_next = nlm_hosts[hash];
110 nlm_hosts[hash] = host;
111 }
112 nlm_get_host(host);
113 up(&nlm_host_sema);
114 return host;
115 }
116 }
117
118 /* special hack for nlmsvc_invalidate_client */
119 if (sin == NULL)
120 goto nohost;
121
122 /* Ooops, no host found, create it */
123 dprintk("lockd: creating host entry\n");
124
125 if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
126 goto nohost;
127 memset(host, 0, sizeof(*host));
128
129 addr = sin->sin_addr.s_addr;
130 sprintf(host->h_name, "%d.%d.%d.%d",
131 (unsigned char) (ntohl(addr) >> 24),
132 (unsigned char) (ntohl(addr) >> 16),
133 (unsigned char) (ntohl(addr) >> 8),
134 (unsigned char) (ntohl(addr) >> 0));
135
136 host->h_addr = *sin;
137 host->h_addr.sin_port = 0; /* ouch! */
138 host->h_version = version;
139 host->h_proto = proto;
140 host->h_authflavor = RPC_AUTH_UNIX;
141 host->h_rpcclnt = NULL;
142 init_MUTEX(&host->h_sema);
143 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
144 host->h_expires = jiffies + NLM_HOST_EXPIRE;
145 host->h_count = 1;
146 init_waitqueue_head(&host->h_gracewait);
147 host->h_state = 0; /* pseudo NSM state */
148 host->h_nsmstate = 0; /* real NSM state */
149 host->h_exportent = clnt;
150
151 host->h_next = nlm_hosts[hash];
152 nlm_hosts[hash] = host;
153
154 if (++nrhosts > NLM_HOST_MAX)
155 next_gc = 0;
156
157 nohost:
158 up(&nlm_host_sema);
159 return host;
160 }
161
162 /*
163 * Create the NLM RPC client for an NLM peer
164 */
165 struct rpc_clnt *
nlm_bind_host(struct nlm_host * host)166 nlm_bind_host(struct nlm_host *host)
167 {
168 struct rpc_clnt *clnt;
169 struct rpc_xprt *xprt;
170
171 dprintk("lockd: nlm_bind_host(%08x)\n",
172 (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
173
174 /* Lock host handle */
175 down(&host->h_sema);
176
177 /* If we've already created an RPC client, check whether
178 * RPC rebind is required
179 * Note: why keep rebinding if we're on a tcp connection?
180 */
181 if ((clnt = host->h_rpcclnt) != NULL) {
182 xprt = clnt->cl_xprt;
183 if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
184 clnt->cl_port = 0;
185 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
186 dprintk("lockd: next rebind in %ld jiffies\n",
187 host->h_nextrebind - jiffies);
188 }
189 } else {
190 xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
191 if (xprt == NULL)
192 goto forgetit;
193
194 xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
195
196 clnt = rpc_create_client(xprt, host->h_name, &nlm_program,
197 host->h_version, host->h_authflavor);
198 if (clnt == NULL) {
199 xprt_destroy(xprt);
200 goto forgetit;
201 }
202 clnt->cl_autobind = 1; /* turn on pmap queries */
203 xprt->nocong = 1; /* No congestion control for NLM */
204 xprt->resvport = 1; /* NLM requires a reserved port */
205
206 host->h_rpcclnt = clnt;
207 }
208
209 up(&host->h_sema);
210 return clnt;
211
212 forgetit:
213 printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
214 up(&host->h_sema);
215 return NULL;
216 }
217
218 /*
219 * Force a portmap lookup of the remote lockd port
220 */
221 void
nlm_rebind_host(struct nlm_host * host)222 nlm_rebind_host(struct nlm_host *host)
223 {
224 dprintk("lockd: rebind host %s\n", host->h_name);
225 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
226 host->h_rpcclnt->cl_port = 0;
227 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
228 }
229 }
230
231 /*
232 * Increment NLM host count
233 */
nlm_get_host(struct nlm_host * host)234 struct nlm_host * nlm_get_host(struct nlm_host *host)
235 {
236 if (host) {
237 dprintk("lockd: get host %s\n", host->h_name);
238 host->h_count ++;
239 host->h_expires = jiffies + NLM_HOST_EXPIRE;
240 }
241 return host;
242 }
243
244 /*
245 * Release NLM host after use
246 */
nlm_release_host(struct nlm_host * host)247 void nlm_release_host(struct nlm_host *host)
248 {
249 if (host && host->h_count) {
250 dprintk("lockd: release host %s\n", host->h_name);
251 host->h_count --;
252 }
253 }
254
255 /*
256 * Shut down the hosts module.
257 * Note that this routine is called only at server shutdown time.
258 */
259 void
nlm_shutdown_hosts(void)260 nlm_shutdown_hosts(void)
261 {
262 struct nlm_host *host;
263 int i;
264
265 dprintk("lockd: shutting down host module\n");
266 down(&nlm_host_sema);
267
268 /* First, make all hosts eligible for gc */
269 dprintk("lockd: nuking all hosts...\n");
270 for (i = 0; i < NLM_HOST_NRHASH; i++) {
271 for (host = nlm_hosts[i]; host; host = host->h_next)
272 host->h_expires = 0;
273 }
274
275 /* Then, perform a garbage collection pass */
276 nlm_gc_hosts();
277 up(&nlm_host_sema);
278
279 /* complain if any hosts are left */
280 if (nrhosts) {
281 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
282 dprintk("lockd: %d hosts left:\n", nrhosts);
283 for (i = 0; i < NLM_HOST_NRHASH; i++) {
284 for (host = nlm_hosts[i]; host; host = host->h_next) {
285 dprintk(" %s (cnt %d use %d exp %ld)\n",
286 host->h_name, host->h_count,
287 host->h_inuse, host->h_expires);
288 }
289 }
290 }
291 }
292
293 /*
294 * Garbage collect any unused NLM hosts.
295 * This GC combines reference counting for async operations with
296 * mark & sweep for resources held by remote clients.
297 */
298 static void
nlm_gc_hosts(void)299 nlm_gc_hosts(void)
300 {
301 struct nlm_host **q, *host;
302 struct rpc_clnt *clnt;
303 int i;
304
305 dprintk("lockd: host garbage collection\n");
306 for (i = 0; i < NLM_HOST_NRHASH; i++) {
307 for (host = nlm_hosts[i]; host; host = host->h_next)
308 host->h_inuse = 0;
309 }
310
311 /* Mark all hosts that hold locks, blocks or shares */
312 nlmsvc_mark_resources();
313
314 for (i = 0; i < NLM_HOST_NRHASH; i++) {
315 q = &nlm_hosts[i];
316 while ((host = *q) != NULL) {
317 if (host->h_count || host->h_inuse
318 || time_before(jiffies, host->h_expires)) {
319 q = &host->h_next;
320 continue;
321 }
322 dprintk("lockd: delete host %s\n", host->h_name);
323 *q = host->h_next;
324 /* Don't unmonitor hosts that have been invalidated */
325 if (host->h_monitored && !host->h_killed)
326 nsm_unmonitor(host);
327 if ((clnt = host->h_rpcclnt) != NULL) {
328 if (atomic_read(&clnt->cl_users)) {
329 printk(KERN_WARNING
330 "lockd: active RPC handle\n");
331 clnt->cl_dead = 1;
332 } else {
333 rpc_destroy_client(host->h_rpcclnt);
334 }
335 }
336 kfree(host);
337 nrhosts--;
338 }
339 }
340
341 next_gc = jiffies + NLM_HOST_COLLECT;
342 }
343
344