ref: 6ebb8b9e357944cc29ae3fafc0900ee3e325ed39
parent: 55c3138c640967ae82b21feb4c33acb9edcbc75b
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Sun Oct 3 11:58:58 EDT 2021
devip: use better hashipa() macro, use RWlock for arp cache
--- a/sys/src/9/ip/arp.c
+++ b/sys/src/9/ip/arp.c
@@ -33,7 +33,7 @@
*/
struct Arp
{
- QLock;
+ RWlock;
Fs *f;
Arpent *hash[NHASH];
Arpent cache[NCACHE];
@@ -45,7 +45,8 @@
char *Ebadarp = "bad arp";
-#define haship(s) ((s)[IPaddrlen-1]%NHASH)
+/* quick hash for ip addresses */
+#define hashipa(a) (((a)[IPaddrlen-2] + (a)[IPaddrlen-1])%NHASH)
static void rxmitproc(void*);
@@ -95,7 +96,7 @@
Block *bp;
/* take out of current chain */
- for(l = &arp->hash[haship(a->ip)]; *l != nil; l = &((*l)->hash)){
+ for(l = &arp->hash[hashipa(a->ip)]; *l != nil; l = &((*l)->hash)){
if(*l == a){
*l = a->hash;
break;
@@ -127,9 +128,6 @@
a->utime = 0;
a->ctime = 0;
-
- memset(a->ip, 0, sizeof(a->ip));
- memset(a->mac, 0, sizeof(a->mac));
}
/*
@@ -158,7 +156,7 @@
a->ifcid = ifc->ifcid;
/* insert into new chain */
- l = &arp->hash[haship(ip)];
+ l = &arp->hash[hashipa(ip)];
a->hash = *l;
*l = a;
@@ -165,7 +163,18 @@
return a;
}
+static Arpent*
+arplookup(Arp *arp, Ipifc *ifc, uchar *ip)
+{
+ Arpent *a;
+ for(a = arp->hash[hashipa(ip)]; a != nil; a = a->hash){
+ if(a->ifc == ifc && a->ifcid == ifc->ifcid && ipcmp(ip, a->ip) == 0)
+ return a;
+ }
+ return nil;
+}
+
/*
* fill in the media address if we have it. Otherwise return an
* Arpent that represents the state of the address resolution FSM
@@ -175,44 +184,39 @@
Arpent*
arpget(Arp *arp, Block *bp, int version, Ipifc *ifc, uchar *ip, uchar *mac)
{
- Arpent *a;
uchar v6ip[IPaddrlen];
+ Arpent *a;
if(version == V4){
v4tov6(v6ip, ip);
ip = v6ip;
}
-
- qlock(arp);
- for(a = arp->hash[haship(ip)]; a != nil; a = a->hash){
- if(a->ifc == ifc && a->ifcid == ifc->ifcid && ipcmp(ip, a->ip) == 0)
- break;
+ rlock(arp);
+ if((a = arplookup(arp, ifc, ip)) != nil && a->state == AOK){
+ memmove(mac, a->mac, ifc->m->maclen);
+ a->utime = NOW;
+ if(a->utime - a->ctime < 15*60*1000){
+ runlock(arp);
+ return nil;
+ }
}
- if(a == nil){
+ runlock(arp);
+ wlock(arp);
+ if((a = arplookup(arp, ifc, ip)) == nil)
a = newarpent(arp, ip, ifc);
- a->state = AWAIT;
- }
+ a->state = AWAIT;
a->utime = NOW;
- if(a->state == AWAIT){
- if(bp != nil){
- bp->list = nil;
- if(a->hold == nil)
- a->hold = bp;
- else
- a->last->list = bp;
- a->last = bp;
- }
- return a; /* return with arp qlocked */
- }
+ if(bp != nil){
+ /* needs to be a single block */
+ assert(bp->list == nil);
- memmove(mac, a->mac, ifc->m->maclen);
-
- /* remove old entries */
- if(NOW - a->ctime > 15*60*1000)
- cleanarpent(arp, a);
-
- qunlock(arp);
- return nil;
+ if(a->hold == nil)
+ a->hold = bp;
+ else
+ a->last->list = bp;
+ a->last = bp;
+ }
+ return a; /* return with arp locked */
}
/*
@@ -226,9 +230,6 @@
Arpent **l;
Block *bp;
- /* try to keep it around for a second more */
- a->ctime = NOW;
-
/* remove all but the last message */
while((bp = a->hold) != nil){
if(bp == a->last)
@@ -237,6 +238,9 @@
freeblist(bp);
}
+ /* try to keep it around for a second more */
+ a->ctime = a->utime = NOW;
+
/* put on end of re-transmit / timeout chain */
for(l = rxmtunchain(arp, a); *l != nil; l = &(*l)->nextrxt)
;
@@ -245,7 +249,7 @@
if(l == &arp->rxmt[0] || l == &arp->rxmt[1])
wakeup(&arp->rxmtq);
- qunlock(arp);
+ wunlock(arp);
}
/*
@@ -254,7 +258,7 @@
void
arprelease(Arp *arp, Arpent*)
{
- qunlock(arp);
+ wunlock(arp);
}
@@ -274,11 +278,11 @@
rxmtunchain(arp, a);
a->rxtsrem = 0;
}
- a->state = AOK;
- a->ctime = a->utime = NOW;
bp = a->hold;
a->hold = a->last = nil;
- qunlock(arp);
+ a->ctime = a->utime = NOW;
+ a->state = AOK;
+ wunlock(arp);
return bp;
}
@@ -313,37 +317,29 @@
return -1;
arp = fs->arp;
- qlock(arp);
- for(a = arp->hash[haship(ip)]; a != nil; a = a->hash){
- if(a->ifc != ifc || a->ifcid != ifc->ifcid)
- continue;
- if(ipcmp(a->ip, ip) == 0){
- if(version == V4)
- ip += IPv4off;
- bp = arpresolve(arp, a, ifc->m, mac); /* unlocks arp */
- for(; bp != nil; bp = next){
- next = bp->list;
- bp->list = nil;
- if(waserror()){
- freeblistchain(next);
- break;
- }
- ipifcoput(ifc, bp, version, ip);
- poperror();
- }
- return 1;
- }
- }
- if(refresh == 0){
+ wlock(arp);
+ if((a = arplookup(arp, ifc, ip)) == nil){
+ if(refresh){
+ wunlock(arp);
+ return 0;
+ }
a = newarpent(arp, ip, ifc);
- a->state = AOK;
- a->ctime = a->utime = NOW;
- memmove(a->mac, mac, n);
}
- qunlock(arp);
-
- return refresh == 0;
+ if(version == V4)
+ ip += IPv4off;
+ bp = arpresolve(arp, a, ifc->m, mac); /* unlocks arp */
+ for(; bp != nil; bp = next){
+ next = bp->list;
+ bp->list = nil;
+ if(waserror()){
+ freeblistchain(next);
+ break;
+ }
+ ipifcoput(ifc, bp, version, ip);
+ poperror();
+ }
+ return 1;
}
int
@@ -370,10 +366,8 @@
n = getfields(buf, f, nelem(f), 1, " ");
if(strcmp(f[0], "flush") == 0){
- qlock(arp);
+ wlock(arp);
for(a = arp->cache; a < &arp->cache[NCACHE]; a++){
- memset(a->ip, 0, sizeof(a->ip));
- memset(a->mac, 0, sizeof(a->mac));
a->hash = nil;
a->nextrxt = nil;
a->ifc = nil;
@@ -389,7 +383,7 @@
freeblistchain(arp->dropf);
arp->dropf = arp->dropl = nil;
arp->rxmt[0] = arp->rxmt[1] = nil;
- qunlock(arp);
+ wunlock(arp);
} else if(strcmp(f[0], "add") == 0){
switch(n){
default:
@@ -436,13 +430,13 @@
error(Ebadarg);
if (parseip(ip, f[1]) == -1)
error(Ebadip);
- qlock(arp);
- for(a = arp->hash[haship(ip)]; a != nil; a = x){
+ wlock(arp);
+ for(a = arp->hash[hashipa(ip)]; a != nil; a = x){
x = a->hash;
if(ipcmp(ip, a->ip) == 0)
cleanarpent(arp, a);
}
- qunlock(arp);
+ wunlock(arp);
} else
error(Ebadarp);
@@ -472,17 +466,17 @@
continue;
rlock(ifc);
- qlock(arp);
- state = arpstate[a->state];
+ rlock(arp);
ipmove(ip, a->ip);
- if(ifc->m == nil || a->ifcid != ifc->ifcid || !ipv6local(ifc, ia, 0, ip)){
- qunlock(arp);
+ if(ifc->m == nil || a->state == 0 || a->ifc != ifc || a->ifcid != ifc->ifcid || !ipv6local(ifc, ia, 0, ip)){
+ runlock(arp);
runlock(ifc);
continue;
}
mname = ifc->m->name;
+ state = arpstate[a->state];
convmac(mac, a->mac, ifc->m->maclen);
- qunlock(arp);
+ runlock(arp);
runlock(ifc);
n = snprint(up->genbuf, sizeof up->genbuf,
@@ -538,7 +532,7 @@
Block *bp;
Ipifc *ifc;
- qlock(arp);
+ wlock(arp);
/* retransmit ipv6 solicitations */
while((a = arp->rxmt[0]) != nil && NOW - a->ctime > 3*RETRANS_TIMER/4){
@@ -546,7 +540,8 @@
if(a->ifcid == ifc->ifcid){
ndpsendsol(arp->f, ifc, a); /* unlocks arp */
runlock(ifc);
- qlock(arp);
+
+ wlock(arp);
continue;
}
runlock(ifc);
@@ -561,7 +556,7 @@
bp = arp->dropf;
arp->dropf = arp->dropl = nil;
- qunlock(arp);
+ wunlock(arp);
return bp;
}
--- a/sys/src/9/ip/ethermedium.c
+++ b/sys/src/9/ip/ethermedium.c
@@ -267,7 +267,7 @@
bp = multicastarp(er->f, a, ifc->m, mac);
if(bp == nil){
/* don't do anything if it's been less than a second since the last */
- if(NOW - a->ctime < RETRANS_TIMER){
+ if(a->utime - a->ctime < RETRANS_TIMER){
arprelease(er->f->arp, a);
return;
}
@@ -284,6 +284,9 @@
return;
}
}
+
+ /* need to have single block */
+ assert(bp->list == nil);
/* make it a single block with space for the ether header */
bp = padblock(bp, ifc->m->hsize);
--- a/sys/src/9/ip/ipifc.c
+++ b/sys/src/9/ip/ipifc.c
@@ -53,7 +53,7 @@
};
/* quick hash for ip addresses */
-#define hashipa(a) ( ( ((a)[IPaddrlen-2]<<8) | (a)[IPaddrlen-1] )%NHASH )
+#define hashipa(a) (((a)[IPaddrlen-2] + (a)[IPaddrlen-1])%NHASH)
static char tifc[] = "ifc ";