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ndb/dns: another attempt...

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we have to fail the whole query that got no cached
nameservers and nameservers are looping, not just omit
the looping nameserver. issuequery() will refresh
nameserver info for the domain when recursing up.
This commit is contained in:
cinap_lenrek 2013-11-17 06:55:39 +01:00
parent c45386588b
commit 9155b30f6d
1 changed files with 18 additions and 12 deletions
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30
sys/src/cmd/ndb/dnresolve.c
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@ -748,24 +748,22 @@ ipisbm(uchar *ip)
static int
queryloops(Query *qp, RR *rp)
{
DN *ns;
ns = rp->host;
DN *ns = rp->host;
/*
* avoid loops looking up a server under itself
* looking up a server under itself
*/
if(subsume(rp->owner->name, ns->name))
return 1;
/*
* must not cycle on name servers refering
* cycle on name servers refering
* to each another.
*/
for(qp = qp->prev; qp; qp = qp->prev)
for(rp = qp->nsrp; rp; rp = rp->next)
if(rp->host == ns)
return 1;
for(; qp; qp = qp->prev)
if(qp->dp == ns)
return 1;
return 0;
}
@ -812,13 +810,20 @@ serveraddrs(Query *qp, int nd, int depth)
* server addresses, try resolving one via the network.
* Mark any we try to resolve so we don't try a second time.
*/
if(arp == 0)
if(arp == 0){
for(rp = qp->nsrp; rp; rp = rp->next)
if(queryloops(qp, rp))
/*
* give up as we should have got the address
* by higher up nameserver when recursing
* down, or will be queried when recursing up.
*/
return nd;
for(rp = qp->nsrp; rp; rp = rp->next){
if(rp->marker)
continue;
rp->marker = 1;
if(queryloops(qp, rp))
continue;
arp = dnresolve(rp->host->name, Cin, Ta, qp->req, 0,
depth+1, Recurse, 1, 0);
if(arp == nil)
@ -828,6 +833,7 @@ serveraddrs(Query *qp, int nd, int depth)
if(arp)
break;
}
}
/* use any addresses that we found */
for(trp = arp; trp && nd < Maxdest; trp = trp->next){