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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Request reply cache. This was heavily inspired by the
4 * implementation in 4.3BSD/4.4BSD.
5 *
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7 */
8
9#ifndef NFSCACHE_H
10#define NFSCACHE_H
11
12#include <linux/sunrpc/svc.h>
13
14/*
15 * Representation of a reply cache entry.
16 *
17 * Note that we use a sockaddr_in6 to hold the address instead of the more
18 * typical sockaddr_storage. This is for space reasons, since sockaddr_storage
19 * is much larger than a sockaddr_in6.
20 */
21struct svc_cacherep {
22 struct list_head c_lru;
23
24 unsigned char c_state, /* unused, inprog, done */
25 c_type, /* status, buffer */
26 c_secure : 1; /* req came from port < 1024 */
27 struct sockaddr_in6 c_addr;
28 __be32 c_xid;
29 u32 c_prot;
30 u32 c_proc;
31 u32 c_vers;
32 unsigned int c_len;
33 __wsum c_csum;
34 unsigned long c_timestamp;
35 union {
36 struct kvec u_vec;
37 __be32 u_status;
38 } c_u;
39};
40
41#define c_replvec c_u.u_vec
42#define c_replstat c_u.u_status
43
44/* cache entry states */
45enum {
46 RC_UNUSED,
47 RC_INPROG,
48 RC_DONE
49};
50
51/* return values */
52enum {
53 RC_DROPIT,
54 RC_REPLY,
55 RC_DOIT
56};
57
58/*
59 * Cache types.
60 * We may want to add more types one day, e.g. for diropres and
61 * attrstat replies. Using cache entries with fixed length instead
62 * of buffer pointers may be more efficient.
63 */
64enum {
65 RC_NOCACHE,
66 RC_REPLSTAT,
67 RC_REPLBUFF,
68};
69
70/* Cache entries expire after this time period */
71#define RC_EXPIRE (120 * HZ)
72
73/* Checksum this amount of the request */
74#define RC_CSUMLEN (256U)
75
76int nfsd_reply_cache_init(void);
77void nfsd_reply_cache_shutdown(void);
78int nfsd_cache_lookup(struct svc_rqst *);
79void nfsd_cache_update(struct svc_rqst *, int, __be32 *);
80int nfsd_reply_cache_stats_open(struct inode *, struct file *);
81
82#endif /* NFSCACHE_H */