xref: /freebsd/sys/rpc/replay.h (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
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 
33 enum 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 
40 struct replay_cache;
41 
42 /*
43  * Create a new replay cache.
44  */
45 struct replay_cache	*replay_newcache(size_t);
46 
47 /*
48  * Set the replay cache size.
49  */
50 void			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  */
56 void			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  */
75 enum 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  */
82 void			replay_setreply(struct replay_cache *rc,
83     struct rpc_msg *repmsg,  struct sockaddr *addr, struct mbuf *m);
84 
85 #endif /* !_RPC_REPLAY_H */
86