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1/*
2 * Request reply cache. This was heavily inspired by the
3 * implementation in 4.3BSD/4.4BSD.
4 *
5 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
6 */
7
8#ifndef NFSCACHE_H
9#define NFSCACHE_H
10
11#include <linux/sunrpc/svc.h>
12
13/*
14 * Representation of a reply cache entry.
15 *
16 * Note that we use a sockaddr_in6 to hold the address instead of the more
17 * typical sockaddr_storage. This is for space reasons, since sockaddr_storage
18 * is much larger than a sockaddr_in6.
19 */
20struct svc_cacherep {
21 struct hlist_node c_hash;
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/*
71 * If requests are retransmitted within this interval, they're dropped.
72 */
73#define RC_DELAY (HZ/5)
74
75/* Cache entries expire after this time period */
76#define RC_EXPIRE (120 * HZ)
77
78/* Checksum this amount of the request */
79#define RC_CSUMLEN (256U)
80
81int nfsd_reply_cache_init(void);
82void nfsd_reply_cache_shutdown(void);
83int nfsd_cache_lookup(struct svc_rqst *);
84void nfsd_cache_update(struct svc_rqst *, int, __be32 *);
85
86#ifdef CONFIG_NFSD_V4
87void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp);
88#else /* CONFIG_NFSD_V4 */
89static inline void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
90{
91}
92#endif /* CONFIG_NFSD_V4 */
93
94#endif /* NFSCACHE_H */