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 struct nfsd_net; 15 16 /* 17 * Representation of a reply cache entry. 18 * 19 * Note that we use a sockaddr_in6 to hold the address instead of the more 20 * typical sockaddr_storage. This is for space reasons, since sockaddr_storage 21 * is much larger than a sockaddr_in6. 22 */ 23 struct nfsd_cacherep { 24 struct { 25 /* Keep often-read xid, csum in the same cache line: */ 26 __be32 k_xid; 27 __wsum k_csum; 28 u32 k_proc; 29 u32 k_prot; 30 u32 k_vers; 31 unsigned int k_len; 32 struct sockaddr_in6 k_addr; 33 } c_key; 34 35 struct rb_node c_node; 36 struct list_head c_lru; 37 unsigned char c_state, /* unused, inprog, done */ 38 c_type, /* status, buffer */ 39 c_secure : 1; /* req came from port < 1024 */ 40 unsigned long c_timestamp; 41 union { 42 struct kvec u_vec; 43 __be32 u_status; 44 } c_u; 45 }; 46 47 #define c_replvec c_u.u_vec 48 #define c_replstat c_u.u_status 49 50 /* cache entry states */ 51 enum { 52 RC_UNUSED, 53 RC_INPROG, 54 RC_DONE 55 }; 56 57 /* return values */ 58 enum { 59 RC_DROPIT, 60 RC_REPLY, 61 RC_DOIT 62 }; 63 64 /* 65 * Cache types. 66 * We may want to add more types one day, e.g. for diropres and 67 * attrstat replies. Using cache entries with fixed length instead 68 * of buffer pointers may be more efficient. 69 */ 70 enum { 71 RC_NOCACHE, 72 RC_REPLSTAT, 73 RC_REPLBUFF, 74 }; 75 76 /* Cache entries expire after this time period */ 77 #define RC_EXPIRE (120 * HZ) 78 79 /* Checksum this amount of the request */ 80 #define RC_CSUMLEN (256U) 81 82 int nfsd_drc_slab_create(void); 83 void nfsd_drc_slab_free(void); 84 int nfsd_reply_cache_init(struct nfsd_net *); 85 void nfsd_reply_cache_shutdown(struct nfsd_net *); 86 int nfsd_cache_lookup(struct svc_rqst *rqstp, unsigned int start, 87 unsigned int len, struct nfsd_cacherep **cacherep); 88 void nfsd_cache_update(struct svc_rqst *rqstp, struct nfsd_cacherep *rp, 89 int cachetype, __be32 *statp); 90 int nfsd_reply_cache_stats_show(struct seq_file *m, void *v); 91 92 #endif /* NFSCACHE_H */ 93