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 */ 21 struct 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 */ 45 enum { 46 RC_UNUSED, 47 RC_INPROG, 48 RC_DONE 49 }; 50 51 /* return values */ 52 enum { 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 */ 64 enum { 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 76 int nfsd_reply_cache_init(void); 77 void nfsd_reply_cache_shutdown(void); 78 int nfsd_cache_lookup(struct svc_rqst *); 79 void nfsd_cache_update(struct svc_rqst *, int, __be32 *); 80 int nfsd_reply_cache_stats_open(struct inode *, struct file *); 81 82 #endif /* NFSCACHE_H */ 83