1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 * Copyright (c) 2012 by Delphix. All rights reserved.
25 */
26
27 #include <sys/param.h>
28 #include <sys/systm.h>
29 #include <sys/socket.h>
30 #include <sys/syslog.h>
31 #include <sys/systm.h>
32 #include <sys/unistd.h>
33 #include <sys/queue.h>
34 #include <sys/sdt.h>
35 #include <netinet/in.h>
36
37 #include <rpc/rpc.h>
38 #include <rpc/xdr.h>
39 #include <rpc/pmap_prot.h>
40 #include <rpc/pmap_clnt.h>
41 #include <rpc/rpcb_prot.h>
42
43 #include <rpcsvc/nlm_prot.h>
44 #include <rpcsvc/sm_inter.h>
45
46 #include "nlm_impl.h"
47
48 /*
49 * The following errors codes from nlm_null_rpc indicate that the port we have
50 * cached for the client's NLM service is stale and that we need to establish
51 * a new RPC client.
52 */
53 #define NLM_STALE_CLNT(_status) \
54 ((_status) == RPC_PROGUNAVAIL || \
55 (_status) == RPC_PROGVERSMISMATCH || \
56 (_status) == RPC_PROCUNAVAIL || \
57 (_status) == RPC_CANTCONNECT || \
58 (_status) == RPC_XPRTFAILED)
59
60 static struct kmem_cache *nlm_rpch_cache = NULL;
61
62 static int nlm_rpch_ctor(void *, void *, int);
63 static void nlm_rpch_dtor(void *, void *);
64 static void destroy_rpch(nlm_rpc_t *);
65 static nlm_rpc_t *get_nlm_rpc_fromcache(struct nlm_host *, int);
66 static void update_host_rpcbinding(struct nlm_host *, int);
67 static int refresh_nlm_rpc(struct nlm_host *, nlm_rpc_t *);
68 static void nlm_host_rele_rpc_locked(struct nlm_host *, nlm_rpc_t *);
69
70 static nlm_rpc_t *
71 get_nlm_rpc_fromcache(struct nlm_host *hostp, int vers)
72 {
73 nlm_rpc_t *rpcp;
74 bool_t found = FALSE;
75
76 ASSERT(MUTEX_HELD(&hostp->nh_lock));
77 if (TAILQ_EMPTY(&hostp->nh_rpchc))
78 return (NULL);
79
80 TAILQ_FOREACH(rpcp, &hostp->nh_rpchc, nr_link) {
81 if (rpcp->nr_vers == vers) {
82 found = TRUE;
83 break;
84 }
85 }
86
87 if (!found)
88 return (NULL);
89
90 TAILQ_REMOVE(&hostp->nh_rpchc, rpcp, nr_link);
91 return (rpcp);
92 }
93
94 /*
95 * Update host's RPC binding (host->nh_addr).
96 * The function is executed by only one thread at time.
97 */
98 static void
99 update_host_rpcbinding(struct nlm_host *hostp, int vers)
100 {
101 enum clnt_stat stat;
102
103 ASSERT(MUTEX_HELD(&hostp->nh_lock));
104
105 /*
106 * Mark RPC binding state as "update in progress" in order
107 * to say other threads that they need to wait until binding
108 * is fully updated.
109 */
110 hostp->nh_rpcb_state = NRPCB_UPDATE_INPROGRESS;
111 hostp->nh_rpcb_ustat = RPC_SUCCESS;
112 mutex_exit(&hostp->nh_lock);
113
114 stat = rpcbind_getaddr(&hostp->nh_knc, NLM_PROG, vers, &hostp->nh_addr);
115 mutex_enter(&hostp->nh_lock);
116
117 hostp->nh_rpcb_state = ((stat == RPC_SUCCESS) ?
118 NRPCB_UPDATED : NRPCB_NEED_UPDATE);
119
120 hostp->nh_rpcb_ustat = stat;
121 cv_broadcast(&hostp->nh_rpcb_cv);
122 }
123
124 /*
125 * Refresh RPC handle taken from host handles cache.
126 * This function is called when an RPC handle is either
127 * uninitialized or was initialized using a binding that's
128 * no longer current.
129 */
130 static int
131 refresh_nlm_rpc(struct nlm_host *hostp, nlm_rpc_t *rpcp)
132 {
133 int ret;
134
135 if (rpcp->nr_handle == NULL) {
136 bool_t clset = TRUE;
137
138 ret = clnt_tli_kcreate(&hostp->nh_knc, &hostp->nh_addr,
139 NLM_PROG, rpcp->nr_vers, 0, NLM_RPC_RETRIES,
140 CRED(), &rpcp->nr_handle);
141
142 /*
143 * Set the client's CLSET_NODELAYONERR option to true. The
144 * RPC clnt_call interface creates an artificial delay for
145 * certain call errors in order to prevent RPC consumers
146 * from getting into tight retry loops. Since this function is
147 * called by the NLM service routines we would like to avoid
148 * this artificial delay when possible. We do not retry if the
149 * NULL request fails so it is safe for us to turn this option
150 * on.
151 */
152 if (clnt_control(rpcp->nr_handle, CLSET_NODELAYONERR,
153 (char *)&clset)) {
154 NLM_ERR("Unable to set CLSET_NODELAYONERR\n");
155 }
156 } else {
157 ret = clnt_tli_kinit(rpcp->nr_handle, &hostp->nh_knc,
158 &hostp->nh_addr, 0, NLM_RPC_RETRIES, CRED());
159 if (ret == 0) {
160 enum clnt_stat stat;
161
162 /*
163 * Check whether host's RPC binding is still
164 * fresh, i.e. if remote program is still sits
165 * on the same port we assume. Call NULL proc
166 * to do it.
167 *
168 * Note: Even though we set no delay on error on the
169 * client handle the call to nlm_null_rpc can still
170 * delay for 10 seconds before returning an error. For
171 * example the no delay on error option is not honored
172 * for RPC_XPRTFAILED errors (see clnt_cots_kcallit).
173 */
174 stat = nlm_null_rpc(rpcp->nr_handle, rpcp->nr_vers);
175 if (NLM_STALE_CLNT(stat)) {
176 ret = ESTALE;
177 }
178 }
179 }
180
181 return (ret);
182 }
183
184 /*
185 * Get RPC handle that can be used to talk to the NLM
186 * of given version running on given host.
187 * Saves obtained RPC handle to rpcpp argument.
188 *
189 * If error occures, return nonzero error code.
190 */
191 int
192 nlm_host_get_rpc(struct nlm_host *hostp, int vers, nlm_rpc_t **rpcpp)
193 {
194 nlm_rpc_t *rpcp = NULL;
195 int rc;
196
197 mutex_enter(&hostp->nh_lock);
198
199 /*
200 * If this handle is either uninitialized, or was
201 * initialized using binding that's now stale
202 * do the init or re-init.
203 * See comments to enum nlm_rpcb_state for more
204 * details.
205 */
206 again:
207 while (hostp->nh_rpcb_state != NRPCB_UPDATED) {
208 if (hostp->nh_rpcb_state == NRPCB_UPDATE_INPROGRESS) {
209 rc = cv_wait_sig(&hostp->nh_rpcb_cv, &hostp->nh_lock);
210 if (rc == 0) {
211 mutex_exit(&hostp->nh_lock);
212 return (EINTR);
213 }
214 }
215
216 /*
217 * Check if RPC binding was marked for update.
218 * If so, start RPC binding update operation.
219 * NOTE: the operation can be executed by only
220 * one thread at time.
221 */
222 if (hostp->nh_rpcb_state == NRPCB_NEED_UPDATE)
223 update_host_rpcbinding(hostp, vers);
224
225 /*
226 * Check if RPC error occured during RPC binding
227 * update operation. If so, report a correspoding
228 * error.
229 */
230 if (hostp->nh_rpcb_ustat != RPC_SUCCESS) {
231 mutex_exit(&hostp->nh_lock);
232 return (ENOENT);
233 }
234 }
235
236 rpcp = get_nlm_rpc_fromcache(hostp, vers);
237 mutex_exit(&hostp->nh_lock);
238 if (rpcp == NULL) {
239 /*
240 * There weren't any RPC handles in a host
241 * cache. No luck, just create a new one.
242 */
243 rpcp = kmem_cache_alloc(nlm_rpch_cache, KM_SLEEP);
244 rpcp->nr_vers = vers;
245 }
246
247 /*
248 * Refresh RPC binding
249 */
250 rc = refresh_nlm_rpc(hostp, rpcp);
251 if (rc != 0) {
252 if (rc == ESTALE) {
253 /*
254 * Host's RPC binding is stale, we have
255 * to update it. Put the RPC handle back
256 * to the cache and mark the host as
257 * "need update".
258 */
259 mutex_enter(&hostp->nh_lock);
260 hostp->nh_rpcb_state = NRPCB_NEED_UPDATE;
261 nlm_host_rele_rpc_locked(hostp, rpcp);
262 goto again;
263 }
264
265 destroy_rpch(rpcp);
266 return (rc);
267 }
268
269 DTRACE_PROBE2(end, struct nlm_host *, hostp,
270 nlm_rpc_t *, rpcp);
271
272 *rpcpp = rpcp;
273 return (0);
274 }
275
276 void
277 nlm_host_rele_rpc(struct nlm_host *hostp, nlm_rpc_t *rpcp)
278 {
279 mutex_enter(&hostp->nh_lock);
280 nlm_host_rele_rpc_locked(hostp, rpcp);
281 mutex_exit(&hostp->nh_lock);
282 }
283
284 static void
285 nlm_host_rele_rpc_locked(struct nlm_host *hostp, nlm_rpc_t *rpcp)
286 {
287 ASSERT(mutex_owned(&hostp->nh_lock));
288 TAILQ_INSERT_HEAD(&hostp->nh_rpchc, rpcp, nr_link);
289 }
290
291 /*
292 * The function invalidates host's RPC binding by marking it
293 * as not fresh. In this case another time thread tries to
294 * get RPC handle from host's handles cache, host's RPC binding
295 * will be updated.
296 *
297 * The function should be executed when RPC call invoked via
298 * handle taken from RPC cache returns RPC_PROCUNAVAIL.
299 */
300 void
301 nlm_host_invalidate_binding(struct nlm_host *hostp)
302 {
303 mutex_enter(&hostp->nh_lock);
304 hostp->nh_rpcb_state = NRPCB_NEED_UPDATE;
305 mutex_exit(&hostp->nh_lock);
306 }
307
308 void
309 nlm_rpc_init(void)
310 {
311 nlm_rpch_cache = kmem_cache_create("nlm_rpch_cache",
312 sizeof (nlm_rpc_t), 0, nlm_rpch_ctor, nlm_rpch_dtor,
313 NULL, NULL, NULL, 0);
314 }
315
316 void
317 nlm_rpc_cache_destroy(struct nlm_host *hostp)
318 {
319 nlm_rpc_t *rpcp;
320
321 /*
322 * There's no need to lock host's mutex here,
323 * nlm_rpc_cache_destroy() should be called from
324 * only one place: nlm_host_destroy, when all
325 * resources host owns are already cleaned up.
326 * So there shouldn't be any raises.
327 */
328 while ((rpcp = TAILQ_FIRST(&hostp->nh_rpchc)) != NULL) {
329 TAILQ_REMOVE(&hostp->nh_rpchc, rpcp, nr_link);
330 destroy_rpch(rpcp);
331 }
332 }
333
334 /* ARGSUSED */
335 static int
336 nlm_rpch_ctor(void *datap, void *cdrarg, int kmflags)
337 {
338 nlm_rpc_t *rpcp = (nlm_rpc_t *)datap;
339
340 bzero(rpcp, sizeof (*rpcp));
341 return (0);
342 }
343
344 /* ARGSUSED */
345 static void
346 nlm_rpch_dtor(void *datap, void *cdrarg)
347 {
348 nlm_rpc_t *rpcp = (nlm_rpc_t *)datap;
349 ASSERT(rpcp->nr_handle == NULL);
350 }
351
352 static void
353 destroy_rpch(nlm_rpc_t *rpcp)
354 {
355 if (rpcp->nr_handle != NULL) {
356 AUTH_DESTROY(rpcp->nr_handle->cl_auth);
357 CLNT_DESTROY(rpcp->nr_handle);
358 rpcp->nr_handle = NULL;
359 }
360
361 kmem_cache_free(nlm_rpch_cache, rpcp);
362 }