Mirrors/coredns
1
0
Fork 0
mirror of https://github.com/coredns/coredns.git synced 2026-08-20 23:08:28 -04:00
Code Issues Packages Projects Releases Wiki Activity

plugin/file: return referrals after alias resolution (#8341)

Browse Source 
Detect zone cuts while following CNAME and DNAME targets so partial answers carry the child NS and glue records instead of returning SERVFAIL or apex authority. Keep AA set for authoritative alias partial answers while clearing it for referral-only responses.

Fixes #6405
Fixes #6627

Signed-off-by: houyuwushang <liuluoqianqiu@outlook.com>
This commit is contained in:
houyuwushang
2026-07-30 09:12:07 +08:00
committed by GitHub
parent 73cd1efe5b
commit 3c2c33bb50
3 changed files with 329 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
plugin/file/lookup.go
View File

@@ -126,7 +126,7 @@ func (z *Zone) Lookup(ctx context.Context, state request.Request, qname string)
rcode = Success
} else {
ctx = context.WithValue(ctx, dnsserver.LoopKey{}, loop+1)
answer, ns, extra, rcode = z.externalLookup(ctx, state, elem, []dns.RR{cname})
answer, ns, extra, rcode = z.externalLookup(ctx, state, tr, elem, []dns.RR{cname})
}
if do {
@@ -146,22 +146,8 @@ func (z *Zone) Lookup(ctx context.Context, state request.Request, qname string)
// with (e.g. another DNAME). So there is nothing special left here.
}
// If we see NS records, it means the name as been delegated, and we should return the delegation.
if nsrrs := elem.Type(dns.TypeNS); nsrrs != nil {
// If the query is specifically for DS and the qname matches the delegated name, we should
// return the DS in the answer section and leave the rest empty, i.e. just continue the loop
// and continue searching.
if qtype == dns.TypeDS && elem.Name() == qname {
i++
continue
}
glue := tr.Glue(nsrrs, do)
if do {
dss := typeFromElem(elem, dns.TypeDS, do)
nsrrs = append(nsrrs, dss...)
}
// If we see NS records, it means the name has been delegated.
if nsrrs, glue, ok := delegationFromElem(tr, elem, qname, qtype, do); ok {
return nil, nsrrs, glue, Delegation
}
@@ -172,7 +158,7 @@ func (z *Zone) Lookup(ctx context.Context, state request.Request, qname string)
if found && shot {
if rrs := elem.Type(dns.TypeCNAME); len(rrs) > 0 && qtype != dns.TypeCNAME {
ctx = context.WithValue(ctx, dnsserver.LoopKey{}, loop+1)
return z.externalLookup(ctx, state, elem, rrs)
return z.externalLookup(ctx, state, tr, elem, rrs)
}
rrs := elem.Type(qtype)
@@ -211,7 +197,7 @@ func (z *Zone) Lookup(ctx context.Context, state request.Request, qname string)
if rrs := wildElem.TypeForWildcard(dns.TypeCNAME, qname); len(rrs) > 0 && qtype != dns.TypeCNAME {
ctx = context.WithValue(ctx, dnsserver.LoopKey{}, loop+1)
return z.externalLookup(ctx, state, wildElem, rrs)
return z.externalLookup(ctx, state, tr, wildElem, rrs)
}
rrs := wildElem.TypeForWildcard(qtype, qname)
@@ -353,7 +339,7 @@ func (z *Zone) authority(do bool, result Result) []dns.RR {
}
// externalLookup adds signatures and tries to resolve CNAMEs that point to external names.
func (z *Zone) externalLookup(ctx context.Context, state request.Request, elem *tree.Elem, rrs []dns.RR) ([]dns.RR, []dns.RR, []dns.RR, Result) {
func (z *Zone) externalLookup(ctx context.Context, state request.Request, tr *tree.Tree, elem *tree.Elem, rrs []dns.RR) ([]dns.RR, []dns.RR, []dns.RR, Result) {
qtype := state.QType()
do := state.Do()
@@ -364,7 +350,10 @@ func (z *Zone) externalLookup(ctx context.Context, state request.Request, elem *
}
targetName := rrs[0].(*dns.CNAME).Target
elem, _ = z.Search(targetName)
elem, _ = tr.Search(targetName)
if ns, extra, ok := z.findDelegation(tr, targetName, qtype, do, elem); ok {
return rrs, ns, extra, Delegation
}
if elem == nil || (qtype == dns.TypeNS || qtype == dns.TypeSOA && targetName == z.origin) {
lookupRRs, result := z.doLookup(ctx, state, targetName, qtype)
rrs = append(rrs, lookupRRs...)
@@ -384,7 +373,10 @@ Redo:
rrs = append(rrs, sigs...)
}
targetName := cname[0].(*dns.CNAME).Target
elem, _ = z.Search(targetName)
elem, _ = tr.Search(targetName)
if ns, extra, ok := z.findDelegation(tr, targetName, qtype, do, elem); ok {
return rrs, ns, extra, Delegation
}
if elem == nil || (qtype == dns.TypeNS || qtype == dns.TypeSOA && targetName == z.origin) {
lookupRRs, result := z.doLookup(ctx, state, targetName, qtype)
rrs = append(rrs, lookupRRs...)
@@ -413,6 +405,44 @@ Redo:
return rrs, z.ns(do), nil, Success
}
// findDelegation returns the first zone cut between the zone apex and qname.
func (z *Zone) findDelegation(tr *tree.Tree, qname string, qtype uint16, do bool, exact *tree.Elem) (ns, extra []dns.RR, ok bool) {
for i := 1; ; i++ {
name, shot := z.nameFromRight(qname, i)
if shot {
return nil, nil, false
}
if name == qname {
if exact == nil {
return nil, nil, false
}
return delegationFromElem(tr, exact, qname, qtype, do)
}
elem, found := tr.Search(name)
if !found {
continue
}
if ns, extra, ok := delegationFromElem(tr, elem, qname, qtype, do); ok {
return ns, extra, true
}
}
}
// delegationFromElem builds a referral from a zone-cut element. A DS query at
// the cut itself is answered by the parent zone instead of returning a referral.
func delegationFromElem(tr *tree.Tree, elem *tree.Elem, qname string, qtype uint16, do bool) (ns, extra []dns.RR, ok bool) {
ns = elem.Type(dns.TypeNS)
if ns == nil || (qtype == dns.TypeDS && elem.Name() == qname) {
return nil, nil, false
}
extra = tr.Glue(ns, do)
if do {
ns = append(ns, typeFromElem(elem, dns.TypeDS, do)...)
}
return ns, extra, true
}
func (z *Zone) doLookup(ctx context.Context, state request.Request, target string, qtype uint16) ([]dns.RR, Result) {
m, e := z.Upstream.Lookup(ctx, state, target, qtype)
if e != nil {