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 * $FreeBSD$
28 */
29
30#ifndef _RPC_REPLAY_H
31#define _RPC_REPLAY_H
32
33enum replay_state {
34	RS_NEW,			/* new request - caller should execute */
35	RS_DONE,		/* request was executed and reply sent */
36	RS_INPROGRESS,		/* request is being executed now */
37	RS_ERROR		/* allocation or other failure */
38};
39
40struct replay_cache;
41
42/*
43 * Create a new replay cache.
44 */
45struct replay_cache	*replay_newcache(size_t);
46
47/*
48 * Set the replay cache size.
49 */
50void			replay_setsize(struct replay_cache *, size_t);
51
52/*
53 * Free a replay cache. Caller must ensure that no cache entries are
54 * in-progress.
55 */
56void			replay_freecache(struct replay_cache *rc);
57
58/*
59 * Check a replay cache for a message from a given address.
60 *
61 * If this is a new request, RS_NEW is returned. Caller should call
62 * replay_setreply with the results of the request.
63 *
64 * If this is a request which is currently executing
65 * (i.e. replay_setreply hasn't been called for it yet), RS_INPROGRESS
66 * is returned. The caller should silently drop the request.
67 *
68 * If a reply to this message already exists, *repmsg and *mp are set
69 * to point at the reply and, RS_DONE is returned. The caller should
70 * re-send this reply.
71 *
72 * If the attempt to update the replay cache or copy a replay failed
73 * for some reason (typically memory shortage), RS_ERROR is returned.
74 */
75enum replay_state	replay_find(struct replay_cache *rc,
76    struct rpc_msg *msg, struct sockaddr *addr,
77    struct rpc_msg *repmsg, struct mbuf **mp);
78
79/*
80 * Call this after executing a request to record the reply.
81 */
82void			replay_setreply(struct replay_cache *rc,
83    struct rpc_msg *repmsg,  struct sockaddr *addr, struct mbuf *m);
84
85#endif /* !_RPC_REPLAY_H */
86