replay.c revision 211830 
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 211830 2010-08-25 23:23:00Z rmacklem $");
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	mtx_lock(&rc->rc_lock);
94	rc->rc_maxsize = newmaxsize;
95	replay_prune(rc);
96	mtx_unlock(&rc->rc_lock);
97}
98
99void
100replay_freecache(struct replay_cache *rc)
101{
102
103	mtx_lock(&rc->rc_lock);
104	while (TAILQ_FIRST(&rc->rc_all))
105		replay_free(rc, TAILQ_FIRST(&rc->rc_all));
106	mtx_destroy(&rc->rc_lock);
107	free(rc, M_RPC);
108}
109
110static struct replay_cache_entry *
111replay_alloc(struct replay_cache *rc,
112    struct rpc_msg *msg, struct sockaddr *addr, int h)
113{
114	struct replay_cache_entry *rce;
115
116	rc->rc_count++;
117	rce = malloc(sizeof(*rce), M_RPC, M_NOWAIT|M_ZERO);
118	rce->rce_hash = h;
119	rce->rce_msg = *msg;
120	bcopy(addr, &rce->rce_addr, addr->sa_len);
121
122	TAILQ_INSERT_HEAD(&rc->rc_cache[h], rce, rce_link);
123	TAILQ_INSERT_HEAD(&rc->rc_all, rce, rce_alllink);
124
125	return (rce);
126}
127
128static void
129replay_free(struct replay_cache *rc, struct replay_cache_entry *rce)
130{
131
132	rc->rc_count--;
133	TAILQ_REMOVE(&rc->rc_cache[rce->rce_hash], rce, rce_link);
134	TAILQ_REMOVE(&rc->rc_all, rce, rce_alllink);
135	if (rce->rce_repbody) {
136		rc->rc_size -= m_length(rce->rce_repbody, NULL);
137		m_freem(rce->rce_repbody);
138	}
139	free(rce, M_RPC);
140}
141
142static void
143replay_prune(struct replay_cache *rc)
144{
145	struct replay_cache_entry *rce;
146	bool_t freed_one;
147
148	if (rc->rc_count >= REPLAY_MAX || rc->rc_size > rc->rc_maxsize) {
149		do {
150			freed_one = FALSE;
151			/*
152			 * Try to free an entry. Don't free in-progress entries
153			 */
154			TAILQ_FOREACH_REVERSE(rce, &rc->rc_all,
155			    replay_cache_list, rce_alllink) {
156				if (rce->rce_repmsg.rm_xid) {
157					replay_free(rc, rce);
158					freed_one = TRUE;
159					break;
160				}
161			}
162		} while (freed_one
163		    && (rc->rc_count >= REPLAY_MAX
164			|| rc->rc_size > rc->rc_maxsize));
165	}
166}
167
168enum replay_state
169replay_find(struct replay_cache *rc, struct rpc_msg *msg,
170    struct sockaddr *addr, struct rpc_msg *repmsg, struct mbuf **mp)
171{
172	int h = HASHSTEP(HASHINIT, msg->rm_xid) % REPLAY_HASH_SIZE;
173	struct replay_cache_entry *rce;
174
175	mtx_lock(&rc->rc_lock);
176	TAILQ_FOREACH(rce, &rc->rc_cache[h], rce_link) {
177		if (rce->rce_msg.rm_xid == msg->rm_xid
178		    && rce->rce_msg.rm_call.cb_prog == msg->rm_call.cb_prog
179		    && rce->rce_msg.rm_call.cb_vers == msg->rm_call.cb_vers
180		    && rce->rce_msg.rm_call.cb_proc == msg->rm_call.cb_proc
181		    && rce->rce_addr.ss_len == addr->sa_len
182		    && bcmp(&rce->rce_addr, addr, addr->sa_len) == 0) {
183			if (rce->rce_repmsg.rm_xid) {
184				/*
185				 * We have a reply for this
186				 * message. Copy it and return. Keep
187				 * replay_all LRU sorted
188				 */
189				TAILQ_REMOVE(&rc->rc_all, rce, rce_alllink);
190				TAILQ_INSERT_HEAD(&rc->rc_all, rce,
191				    rce_alllink);
192				*repmsg = rce->rce_repmsg;
193				if (rce->rce_repbody) {
194					*mp = m_copym(rce->rce_repbody,
195					    0, M_COPYALL, M_NOWAIT);
196					mtx_unlock(&rc->rc_lock);
197					if (!*mp)
198						return (RS_ERROR);
199				} else {
200					mtx_unlock(&rc->rc_lock);
201				}
202				return (RS_DONE);
203			} else {
204				mtx_unlock(&rc->rc_lock);
205				return (RS_INPROGRESS);
206			}
207		}
208	}
209
210	replay_prune(rc);
211
212	rce = replay_alloc(rc, msg, addr, h);
213
214	mtx_unlock(&rc->rc_lock);
215
216	if (!rce)
217		return (RS_ERROR);
218	else
219		return (RS_NEW);
220}
221
222void
223replay_setreply(struct replay_cache *rc,
224    struct rpc_msg *repmsg, struct sockaddr *addr, struct mbuf *m)
225{
226	int h = HASHSTEP(HASHINIT, repmsg->rm_xid) % REPLAY_HASH_SIZE;
227	struct replay_cache_entry *rce;
228
229	/*
230	 * Copy the reply before the lock so we can sleep.
231	 */
232	if (m)
233		m = m_copym(m, 0, M_COPYALL, M_WAITOK);
234
235	mtx_lock(&rc->rc_lock);
236	TAILQ_FOREACH(rce, &rc->rc_cache[h], rce_link) {
237		if (rce->rce_msg.rm_xid == repmsg->rm_xid
238		    && rce->rce_addr.ss_len == addr->sa_len
239		    && bcmp(&rce->rce_addr, addr, addr->sa_len) == 0) {
240			break;
241		}
242	}
243	if (rce) {
244		rce->rce_repmsg = *repmsg;
245		rce->rce_repbody = m;
246		if (m)
247			rc->rc_size += m_length(m, NULL);
248	}
249	mtx_unlock(&rc->rc_lock);
250}
251