replay.c revision 184588 
1/*-
2 * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
3 * Authors: Doug Rabson <dfr@rabson.org>
4 * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/sys/rpc/replay.c 184588 2008-11-03 10:38:00Z dfr $");
30
31#include <sys/param.h>
32#include <sys/hash.h>
33#include <sys/kernel.h>
34#include <sys/lock.h>
35#include <sys/mbuf.h>
36#include <sys/mutex.h>
37#include <sys/queue.h>
38
39#include <rpc/rpc.h>
40#include <rpc/replay.h>
41
42struct replay_cache_entry {
43	int		rce_hash;
44	struct rpc_msg	rce_msg;
45	struct sockaddr_storage rce_addr;
46	struct rpc_msg	rce_repmsg;
47	struct mbuf	*rce_repbody;
48
49	TAILQ_ENTRY(replay_cache_entry) rce_link;
50	TAILQ_ENTRY(replay_cache_entry) rce_alllink;
51};
52TAILQ_HEAD(replay_cache_list, replay_cache_entry);
53
54static struct replay_cache_entry *
55		replay_alloc(struct replay_cache *rc, struct rpc_msg *msg,
56		    struct sockaddr *addr, int h);
57static void	replay_free(struct replay_cache *rc,
58    struct replay_cache_entry *rce);
59static void	replay_prune(struct replay_cache *rc);
60
61#define REPLAY_HASH_SIZE	256
62#define REPLAY_MAX		1024
63
64struct replay_cache {
65	struct replay_cache_list	rc_cache[REPLAY_HASH_SIZE];
66	struct replay_cache_list	rc_all;
67	struct mtx			rc_lock;
68	int				rc_count;
69	size_t				rc_size;
70	size_t				rc_maxsize;
71};
72
73struct replay_cache *
74replay_newcache(size_t maxsize)
75{
76	struct replay_cache *rc;
77	int i;
78
79	rc = malloc(sizeof(*rc), M_RPC, M_WAITOK|M_ZERO);
80	for (i = 0; i < REPLAY_HASH_SIZE; i++)
81		TAILQ_INIT(&rc->rc_cache[i]);
82	TAILQ_INIT(&rc->rc_all);
83	mtx_init(&rc->rc_lock, "rc_lock", NULL, MTX_DEF);
84	rc->rc_maxsize = maxsize;
85
86	return (rc);
87}
88
89void
90replay_setsize(struct replay_cache *rc, size_t newmaxsize)
91{
92
93	rc->rc_maxsize = newmaxsize;
94	replay_prune(rc);
95}
96
97void
98replay_freecache(struct replay_cache *rc)
99{
100
101	mtx_lock(&rc->rc_lock);
102	while (TAILQ_FIRST(&rc->rc_all))
103		replay_free(rc, TAILQ_FIRST(&rc->rc_all));
104	mtx_destroy(&rc->rc_lock);
105	free(rc, M_RPC);
106}
107
108static struct replay_cache_entry *
109replay_alloc(struct replay_cache *rc,
110    struct rpc_msg *msg, struct sockaddr *addr, int h)
111{
112	struct replay_cache_entry *rce;
113
114	rc->rc_count++;
115	rce = malloc(sizeof(*rce), M_RPC, M_NOWAIT|M_ZERO);
116	rce->rce_hash = h;
117	rce->rce_msg = *msg;
118	bcopy(addr, &rce->rce_addr, addr->sa_len);
119
120	TAILQ_INSERT_HEAD(&rc->rc_cache[h], rce, rce_link);
121	TAILQ_INSERT_HEAD(&rc->rc_all, rce, rce_alllink);
122
123	return (rce);
124}
125
126static void
127replay_free(struct replay_cache *rc, struct replay_cache_entry *rce)
128{
129
130	rc->rc_count--;
131	TAILQ_REMOVE(&rc->rc_cache[rce->rce_hash], rce, rce_link);
132	TAILQ_REMOVE(&rc->rc_all, rce, rce_alllink);
133	if (rce->rce_repbody) {
134		rc->rc_size -= m_length(rce->rce_repbody, NULL);
135		m_freem(rce->rce_repbody);
136	}
137	free(rce, M_RPC);
138}
139
140static void
141replay_prune(struct replay_cache *rc)
142{
143	struct replay_cache_entry *rce;
144	bool_t freed_one;
145
146	if (rc->rc_count >= REPLAY_MAX || rc->rc_size > rc->rc_maxsize) {
147		freed_one = FALSE;
148		do {
149			/*
150			 * Try to free an entry. Don't free in-progress entries
151			 */
152			TAILQ_FOREACH_REVERSE(rce, &rc->rc_all,
153			    replay_cache_list, rce_alllink) {
154				if (rce->rce_repmsg.rm_xid) {
155					replay_free(rc, rce);
156					freed_one = TRUE;
157					break;
158				}
159			}
160		} while (freed_one
161		    && (rc->rc_count >= REPLAY_MAX
162			|| rc->rc_size > rc->rc_maxsize));
163	}
164}
165
166enum replay_state
167replay_find(struct replay_cache *rc, struct rpc_msg *msg,
168    struct sockaddr *addr, struct rpc_msg *repmsg, struct mbuf **mp)
169{
170	int h = HASHSTEP(HASHINIT, msg->rm_xid) % REPLAY_HASH_SIZE;
171	struct replay_cache_entry *rce;
172
173	mtx_lock(&rc->rc_lock);
174	TAILQ_FOREACH(rce, &rc->rc_cache[h], rce_link) {
175		if (rce->rce_msg.rm_xid == msg->rm_xid
176		    && rce->rce_msg.rm_call.cb_prog == msg->rm_call.cb_prog
177		    && rce->rce_msg.rm_call.cb_vers == msg->rm_call.cb_vers
178		    && rce->rce_msg.rm_call.cb_proc == msg->rm_call.cb_proc
179		    && rce->rce_addr.ss_len == addr->sa_len
180		    && bcmp(&rce->rce_addr, addr, addr->sa_len) == 0) {
181			if (rce->rce_repmsg.rm_xid) {
182				/*
183				 * We have a reply for this
184				 * message. Copy it and return. Keep
185				 * replay_all LRU sorted
186				 */
187				TAILQ_REMOVE(&rc->rc_all, rce, rce_alllink);
188				TAILQ_INSERT_HEAD(&rc->rc_all, rce,
189				    rce_alllink);
190				*repmsg = rce->rce_repmsg;
191				if (rce->rce_repbody) {
192					*mp = m_copym(rce->rce_repbody,
193					    0, M_COPYALL, M_NOWAIT);
194					mtx_unlock(&rc->rc_lock);
195					if (!*mp)
196						return (RS_ERROR);
197				} else {
198					mtx_unlock(&rc->rc_lock);
199				}
200				return (RS_DONE);
201			} else {
202				mtx_unlock(&rc->rc_lock);
203				return (RS_INPROGRESS);
204			}
205		}
206	}
207
208	replay_prune(rc);
209
210	rce = replay_alloc(rc, msg, addr, h);
211
212	mtx_unlock(&rc->rc_lock);
213
214	if (!rce)
215		return (RS_ERROR);
216	else
217		return (RS_NEW);
218}
219
220void
221replay_setreply(struct replay_cache *rc,
222    struct rpc_msg *repmsg, struct sockaddr *addr, struct mbuf *m)
223{
224	int h = HASHSTEP(HASHINIT, repmsg->rm_xid) % REPLAY_HASH_SIZE;
225	struct replay_cache_entry *rce;
226
227	/*
228	 * Copy the reply before the lock so we can sleep.
229	 */
230	if (m)
231		m = m_copym(m, 0, M_COPYALL, M_WAITOK);
232
233	mtx_lock(&rc->rc_lock);
234	TAILQ_FOREACH(rce, &rc->rc_cache[h], rce_link) {
235		if (rce->rce_msg.rm_xid == repmsg->rm_xid
236		    && rce->rce_addr.ss_len == addr->sa_len
237		    && bcmp(&rce->rce_addr, addr, addr->sa_len) == 0) {
238			break;
239		}
240	}
241	if (rce) {
242		rce->rce_repmsg = *repmsg;
243		rce->rce_repbody = m;
244		if (m)
245			rc->rc_size += m_length(m, NULL);
246	}
247	mtx_unlock(&rc->rc_lock);
248}
249