ndb/dns: various changes

stop absolute/relative dual use of RR.ttl. now RR.ttl is
*always* the *relative* ttl value. we derive absolute
timeout in RR.expire.

remove unused lookuptime field in DN. replace refs and
keep with mark field in DN. we do not care about the
number of references. only *iff* it is referenced, so
use a single bit for that (bit 0). for keep, we use
bit 1.

remove dolock parameter in dnagenever(), it is not
needed. we always need to lock.

mark local dns servers and domains as never to be aged.

the keeper bit is *just* a cache optimization, preventing
the domain and the domains it points to from being flushed.
it should not be used as a write protect bit in rrattach()
for preventing spoofing as it will prevent updates of say,
cname domains.

remove "removing spam ..." message. these are usualy just
hints, so normal. still, remove the hint as we currently
do no check if the nameserver has authority over the
cname domain.

remove "mydnsquery: trying to send to myself (%s); bzzzt"
message. this can happen when myaddr() fails for other
reasons. myaddr() will print error for us anyway.

1 files changed, 6 insertions, 11 deletions

diff --git a/sys/src/cmd/ndb/dnresolve.c b/sys/src/cmd/ndb/dnresolve.c
index b21289c2b..6e8709e94 100644
--- a/sys/src/cmd/ndb/dnresolve.c
+++ b/sys/src/cmd/ndb/dnresolve.c
@@ -346,7 +346,7 @@ issuequery(Query *qp, char *name, int class, int depth, int recurse)
 			nsrp = randomize(rrlookup(nsdp, Tns, NOneg));
 
 		/* if the entry timed out, ignore it */
-		if(nsrp && nsrp->ttl < now)
+		if(nsrp && !nsrp->db && (long)(nsrp->expire - now) <= 0)
 			rrfreelistptr(&nsrp);
 
 		if(nsrp){
@@ -397,7 +397,7 @@ dnresolve1(char *name, int class, int type, Request *req, int depth,
 			}
 		} else
 			/* cached entry must still be valid */
-			if(rp->ttl > now)
+			if((long)(rp->expire - now) > 0)
 				/* but Tall entries are special */
 				if(type != Tall || rp->query == Tall) {
 					noteinmem();
@@ -850,7 +850,7 @@ cacheneg(DN *dp, int type, int rcode, RR *soarr)
 
 	/* the attach can cause soarr to be freed so mine it now */
 	if(soarr != nil && soarr->soa != nil)
-		ttl = soarr->soa->minttl+now;
+		ttl = soarr->soa->minttl;
 	else
 		ttl = 5*Min;
 
@@ -893,11 +893,8 @@ mydnsquery(Query *qp, int medium, uchar *udppkt, int len)
 
 	rv = -1;
 	snprint(domain, sizeof(domain), "%I", udppkt);
-	if (myaddr(domain)) {
-		dnslog("mydnsquery: trying to send to myself (%s); bzzzt",
-			domain);
+	if (myaddr(domain))
 		return rv;
-	}
 	switch (medium) {
 	case Udp:
 		nfd = dup(qp->udpfd, -1);
@@ -1094,13 +1091,11 @@ procansw(Query *qp, DNSmsg *mp, uchar *srcip, int depth, Dest *p)
 	if(mp->an){
 		/*
 		 * only use cname answer when returned. some dns servers
-		 * attach spam address records which poisons the cache.
+		 * attach (potential) spam hint address records which poisons the cache.
 		 */
 		if((tp = rrremtype(&mp->an, Tcname)) != 0){
-			if(mp->an){
-				dnslog("removing spam %Q for %Q from %I", mp->an, tp, srcip);
+			if(mp->an)
 				rrfreelist(mp->an);
-			}
 			mp->an = tp;
 		}
 		rrattach(mp->an, (mp->flags & Fauth) != 0);