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 #include "netns.h"
14
15 /*
16 * Representation of a reply cache entry.
17 *
18 * Note that we use a sockaddr_in6 to hold the address instead of the more
19 * typical sockaddr_storage. This is for space reasons, since sockaddr_storage
20 * is much larger than a sockaddr_in6.
21 */
22 struct nfsd_cacherep {
23 struct {
24 /* Keep often-read xid, csum in the same cache line: */
25 __be32 k_xid;
26 __wsum k_csum;
27 u32 k_proc;
28 u32 k_prot;
29 u32 k_vers;
30 unsigned int k_len;
31 struct sockaddr_in6 k_addr;
32 } c_key;
33
34 struct rb_node c_node;
35 struct list_head c_lru;
36 unsigned char c_state, /* unused, inprog, done */
37 c_type, /* status, buffer */
38 c_secure : 1; /* req came from port < 1024 */
39 unsigned long c_timestamp;
40 union {
41 struct kvec u_vec;
42 __be32 u_status;
43 } c_u;
44 };
45
46 #define c_replvec c_u.u_vec
47 #define c_replstat c_u.u_status
48
49 /* cache entry states */
50 enum {
51 RC_UNUSED,
52 RC_INPROG,
53 RC_DONE
54 };
55
56 /* return values */
57 enum {
58 RC_DROPIT,
59 RC_REPLY,
60 RC_DOIT
61 };
62
63 /*
64 * Cache types.
65 * We may want to add more types one day, e.g. for diropres and
66 * attrstat replies. Using cache entries with fixed length instead
67 * of buffer pointers may be more efficient.
68 */
69 enum {
70 RC_NOCACHE,
71 RC_REPLSTAT,
72 RC_REPLBUFF,
73 };
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
81 int nfsd_drc_slab_create(void);
82 void nfsd_drc_slab_free(void);
83 int nfsd_reply_cache_init(struct nfsd_net *);
84 void nfsd_reply_cache_shutdown(struct nfsd_net *);
85 int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start,
86 unsigned int len, struct nfsd_cacherep **cacherep);
87 void nfsd_cache_update(struct svc_rqst *rqstp, struct nfsd_cacherep *rp,
88 int cachetype, __be32 *statp);
89 int nfsd_reply_cache_stats_show(struct seq_file *m, void *v);
90
91 #endif /* NFSCACHE_H */
92
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