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 */ 20 struct svc_cacherep { 21 struct list_head c_lru; 22 23 unsigned char c_state, /* unused, inprog, done */ 24 c_type, /* status, buffer */ 25 c_secure : 1; /* req came from port < 1024 */ 26 struct sockaddr_in6 c_addr; 27 __be32 c_xid; 28 u32 c_prot; 29 u32 c_proc; 30 u32 c_vers; 31 unsigned int c_len; 32 __wsum c_csum; 33 unsigned long c_timestamp; 34 union { 35 struct kvec u_vec; 36 __be32 u_status; 37 } c_u; 38 }; 39 40 #define c_replvec c_u.u_vec 41 #define c_replstat c_u.u_status 42 43 /* cache entry states */ 44 enum { 45 RC_UNUSED, 46 RC_INPROG, 47 RC_DONE 48 }; 49 50 /* return values */ 51 enum { 52 RC_DROPIT, 53 RC_REPLY, 54 RC_DOIT 55 }; 56 57 /* 58 * Cache types. 59 * We may want to add more types one day, e.g. for diropres and 60 * attrstat replies. Using cache entries with fixed length instead 61 * of buffer pointers may be more efficient. 62 */ 63 enum { 64 RC_NOCACHE, 65 RC_REPLSTAT, 66 RC_REPLBUFF, 67 }; 68 69 /* 70 * If requests are retransmitted within this interval, they're dropped. 71 */ 72 #define RC_DELAY (HZ/5) 73 74 /* Cache entries expire after this time period */ 75 #define RC_EXPIRE (120 * HZ) 76 77 /* Checksum this amount of the request */ 78 #define RC_CSUMLEN (256U) 79 80 int nfsd_reply_cache_init(void); 81 void nfsd_reply_cache_shutdown(void); 82 int nfsd_cache_lookup(struct svc_rqst *); 83 void nfsd_cache_update(struct svc_rqst *, int, __be32 *); 84 int nfsd_reply_cache_stats_open(struct inode *, struct file *); 85 86 #endif /* NFSCACHE_H */ 87