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/* $OpenBSD: nfs_srvcache.c,v 1.29 2019/12/05 10:41:57 mpi Exp $ */
/* $NetBSD: nfs_srvcache.c,v 1.12 1996/02/18 11:53:49 fvdl Exp $ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)nfs_srvcache.c 8.3 (Berkeley) 3/30/95
*/
/*
* Reference: Chet Juszczak, "Improving the Performance and Correctness
* of an NFS Server", in Proc. Winter 1989 USENIX Conference,
* pages 53-63. San Diego, February 1989.
*/
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/queue.h>
#include <crypto/siphash.h>
#include <netinet/in.h>
#include <nfs/nfsproto.h>
#include <nfs/nfs.h>
#include <nfs/nfsrvcache.h>
#include <nfs/nfs_var.h>
extern struct nfsstats nfsstats;
extern int nfsv2_procid[NFS_NPROCS];
long numnfsrvcache, desirednfsrvcache = NFSRVCACHESIZ;
struct nfsrvcache *nfsrv_lookupcache(struct nfsrv_descript *);
void nfsrv_cleanentry(struct nfsrvcache *);
LIST_HEAD(nfsrvhash, nfsrvcache) *nfsrvhashtbl;
SIPHASH_KEY nfsrvhashkey;
TAILQ_HEAD(nfsrvlru, nfsrvcache) nfsrvlruhead;
u_long nfsrvhash;
#define NFSRCHASH(xid) \
(&nfsrvhashtbl[SipHash24(&nfsrvhashkey, &(xid), sizeof(xid)) & nfsrvhash])
#define NETFAMILY(rp) \
(((rp)->rc_flag & RC_INETADDR) ? AF_INET : AF_UNSPEC)
/* Array that defines which nfs rpc's are nonidempotent */
int nonidempotent[NFS_NPROCS] = {
0, 0, 1, 0, 0, 0, 0, 1,
1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0
};
/* True iff the rpc reply is an nfs status ONLY! */
int nfsv2_repstat[NFS_NPROCS] = {
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 1, 1, 1, 0, 1,
0, 0
};
void
nfsrv_cleanentry(struct nfsrvcache *rp)
{
if ((rp->rc_flag & RC_REPMBUF) != 0)
m_freem(rp->rc_reply);
if ((rp->rc_flag & RC_NAM) != 0)
m_free(rp->rc_nam);
rp->rc_flag &= ~(RC_REPSTATUS|RC_REPMBUF);
}
/* Initialize the server request cache list */
void
nfsrv_initcache(void)
{
nfsrvhashtbl = hashinit(desirednfsrvcache, M_NFSD, M_WAITOK, &nfsrvhash);
arc4random_buf(&nfsrvhashkey, sizeof(nfsrvhashkey));
TAILQ_INIT(&nfsrvlruhead);
}
/*
* Look for the request in the cache
* If found then
* return action and optionally reply
* else
* insert it in the cache
*
* The rules are as follows:
* - if in progress, return DROP request
* - if completed within DELAY of the current time, return DROP it
* - if completed a longer time ago return REPLY if the reply was cached or
* return DOIT
* Update/add new request at end of lru list
*/
int
nfsrv_getcache(struct nfsrv_descript *nd, struct nfssvc_sock *slp,
struct mbuf **repp)
{
struct nfsrvhash *hash;
struct nfsrvcache *rp;
struct mbuf *mb;
struct sockaddr_in *saddr;
int ret;
/*
* Don't cache recent requests for reliable transport protocols.
* (Maybe we should for the case of a reconnect, but..)
*/
if (!nd->nd_nam2)
return (RC_DOIT);
rp = nfsrv_lookupcache(nd);
if (rp) {
/* If not at end of LRU chain, move it there */
if (TAILQ_NEXT(rp, rc_lru)) {
TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
}
if (rp->rc_state == RC_UNUSED)
panic("nfsrv cache");
if (rp->rc_state == RC_INPROG) {
nfsstats.srvcache_inproghits++;
ret = RC_DROPIT;
} else if (rp->rc_flag & RC_REPSTATUS) {
nfsstats.srvcache_nonidemdonehits++;
nfs_rephead(0, nd, slp, rp->rc_status, repp, &mb);
ret = RC_REPLY;
} else if (rp->rc_flag & RC_REPMBUF) {
nfsstats.srvcache_nonidemdonehits++;
*repp = m_copym(rp->rc_reply, 0, M_COPYALL, M_WAIT);
ret = RC_REPLY;
} else {
nfsstats.srvcache_idemdonehits++;
rp->rc_state = RC_INPROG;
ret = RC_DOIT;
}
rp->rc_flag &= ~RC_LOCKED;
if (rp->rc_flag & RC_WANTED) {
rp->rc_flag &= ~RC_WANTED;
wakeup(rp);
}
return (ret);
}
nfsstats.srvcache_misses++;
if (numnfsrvcache < desirednfsrvcache) {
rp = malloc(sizeof(*rp), M_NFSD, M_WAITOK|M_ZERO);
numnfsrvcache++;
rp->rc_flag = RC_LOCKED;
} else {
rp = TAILQ_FIRST(&nfsrvlruhead);
while ((rp->rc_flag & RC_LOCKED) != 0) {
rp->rc_flag |= RC_WANTED;
tsleep_nsec(rp, PZERO-1, "nfsrc", INFSLP);
rp = TAILQ_FIRST(&nfsrvlruhead);
}
rp->rc_flag |= RC_LOCKED;
LIST_REMOVE(rp, rc_hash);
TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
nfsrv_cleanentry(rp);
rp->rc_flag &= (RC_LOCKED | RC_WANTED);
}
TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
rp->rc_state = RC_INPROG;
rp->rc_xid = nd->nd_retxid;
saddr = mtod(nd->nd_nam, struct sockaddr_in *);
switch (saddr->sin_family) {
case AF_INET:
rp->rc_flag |= RC_INETADDR;
rp->rc_inetaddr = saddr->sin_addr.s_addr;
break;
default:
rp->rc_flag |= RC_NAM;
rp->rc_nam = m_copym(nd->nd_nam, 0, M_COPYALL, M_WAIT);
break;
};
rp->rc_proc = nd->nd_procnum;
hash = NFSRCHASH(nd->nd_retxid);
LIST_INSERT_HEAD(hash, rp, rc_hash);
rp->rc_flag &= ~RC_LOCKED;
if (rp->rc_flag & RC_WANTED) {
rp->rc_flag &= ~RC_WANTED;
wakeup(rp);
}
return (RC_DOIT);
}
/* Update a request cache entry after the rpc has been done */
void
nfsrv_updatecache(struct nfsrv_descript *nd, int repvalid,
struct mbuf *repmbuf)
{
struct nfsrvcache *rp;
if (!nd->nd_nam2)
return;
rp = nfsrv_lookupcache(nd);
if (rp) {
nfsrv_cleanentry(rp);
rp->rc_state = RC_DONE;
/*
* If we have a valid reply update status and save
* the reply for non-idempotent rpc's.
*/
if (repvalid && nonidempotent[nd->nd_procnum]) {
if ((nd->nd_flag & ND_NFSV3) == 0 &&
nfsv2_repstat[nfsv2_procid[nd->nd_procnum]]) {
rp->rc_status = nd->nd_repstat;
rp->rc_flag |= RC_REPSTATUS;
} else {
rp->rc_reply = m_copym(repmbuf, 0, M_COPYALL,
M_WAIT);
rp->rc_flag |= RC_REPMBUF;
}
}
rp->rc_flag &= ~RC_LOCKED;
if (rp->rc_flag & RC_WANTED) {
rp->rc_flag &= ~RC_WANTED;
wakeup(rp);
}
return;
}
}
/* Clean out the cache. Called when the last nfsd terminates. */
void
nfsrv_cleancache(void)
{
struct nfsrvcache *rp, *nextrp;
for (rp = TAILQ_FIRST(&nfsrvlruhead); rp != NULL; rp = nextrp) {
nextrp = TAILQ_NEXT(rp, rc_lru);
LIST_REMOVE(rp, rc_hash);
TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
nfsrv_cleanentry(rp);
free(rp, M_NFSD, sizeof(*rp));
}
numnfsrvcache = 0;
}
struct nfsrvcache *
nfsrv_lookupcache(struct nfsrv_descript *nd)
{
struct nfsrvhash *hash;
struct nfsrvcache *rp;
hash = NFSRCHASH(nd->nd_retxid);
loop:
LIST_FOREACH(rp, hash, rc_hash) {
if (nd->nd_retxid == rp->rc_xid &&
nd->nd_procnum == rp->rc_proc &&
netaddr_match(NETFAMILY(rp), &rp->rc_haddr, nd->nd_nam)) {
if ((rp->rc_flag & RC_LOCKED)) {
rp->rc_flag |= RC_WANTED;
tsleep_nsec(rp, PZERO - 1, "nfsrc", INFSLP);
goto loop;
}
rp->rc_flag |= RC_LOCKED;
return (rp);
}
}
return (NULL);
}
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