TrueCloudLab/coredns
16
0
Fork 2
Code Issues Pull requests 1 Projects Releases Packages Wiki Activity Actions

msg.Service: add HostType() method (#627)

Browse source 
This method parses the Host field in the service. It returns 1 or 3
things 1) it is a host 2) an IPv4 address or an 3) IPv6 address.
This simplifies some code a bit and allows for 1 way of parsing the Host
field.

This *only* parse the Host field, Mail and/or Text values should be
checked separately.

We reuse the dns.TypeXXX values for this as to not invent anything new.
This commit is contained in:
Miek Gieben 2017-04-22 07:58:30 +01:00 • committed by GitHub
parent 320cf97868
commit 4c9351b0a3
3 changed files with 115 additions and 41 deletions
Download patch file Download diff file Expand all files Collapse all files

92
middleware/backend_lookup.go
View file

@ -21,9 +21,11 @@ func A(b ServiceBackend, zone string, state request.Request, previousRecords []d
}
for _, serv := range services {
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
what, ip := serv.HostType()
switch what {
case dns.TypeANY:
if Name(state.Name()).Matches(dns.Fqdn(serv.Host)) {
// x CNAME x is a direct loop, don't add those
continue
@ -67,9 +69,11 @@ func A(b ServiceBackend, zone string, state request.Request, previousRecords []d
records = append(records, newRecord)
records = append(records, m1.Answer...)
continue
case ip.To4() != nil:
records = append(records, serv.NewA(state.QName(), ip.To4()))
case ip.To4() == nil:
case dns.TypeA:
records = append(records, serv.NewA(state.QName(), ip))
case dns.TypeAAAA:
// nodata?
}
}
@ -84,9 +88,11 @@ func AAAA(b ServiceBackend, zone string, state request.Request, previousRecords
}
for _, serv := range services {
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
what, ip := serv.HostType()
switch what {
case dns.TypeANY:
// Try to resolve as CNAME if it's not an IP, but only if we don't create loops.
if Name(state.Name()).Matches(dns.Fqdn(serv.Host)) {
// x CNAME x is a direct loop, don't add those
@ -131,10 +137,12 @@ func AAAA(b ServiceBackend, zone string, state request.Request, previousRecords
records = append(records, m1.Answer...)
continue
// both here again
case ip.To4() != nil:
case dns.TypeA:
// nada?
case ip.To4() == nil:
records = append(records, serv.NewAAAA(state.QName(), ip.To16()))
case dns.TypeAAAA:
records = append(records, serv.NewAAAA(state.QName(), ip))
}
}
return records, debug, nil
@ -170,9 +178,11 @@ func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (rec
w1 *= float64(serv.Weight)
}
weight := uint16(math.Floor(w1))
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
what, ip := serv.HostType()
switch what {
case dns.TypeANY:
srv := serv.NewSRV(state.QName(), weight)
records = append(records, srv)
@ -214,18 +224,13 @@ func SRV(b ServiceBackend, zone string, state request.Request, opt Options) (rec
debug = append(debug, debugAddr...)
}
// IPv6 lookups here as well? AAAA(zone, state1, nil).
case ip.To4() != nil:
case dns.TypeA, dns.TypeAAAA:
serv.Host = msg.Domain(serv.Key)
srv := serv.NewSRV(state.QName(), weight)
records = append(records, srv)
extra = append(extra, serv.NewA(srv.Target, ip.To4()))
case ip.To4() == nil:
serv.Host = msg.Domain(serv.Key)
srv := serv.NewSRV(state.QName(), weight)
records = append(records, srv)
extra = append(extra, serv.NewAAAA(srv.Target, ip.To16()))
extra = append(extra, newAddress(serv, srv.Target, ip, what))
}
}
return records, extra, debug, nil
@ -243,9 +248,9 @@ func MX(b ServiceBackend, zone string, state request.Request, opt Options) (reco
if !serv.Mail {
continue
}
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
what, ip := serv.HostType()
switch what {
case dns.TypeANY:
mx := serv.NewMX(state.QName())
records = append(records, mx)
if _, ok := lookup[mx.Mx]; ok {
@ -284,14 +289,11 @@ func MX(b ServiceBackend, zone string, state request.Request, opt Options) (reco
debug = append(debug, debugAddr...)
}
// e.AAAA as well
case ip.To4() != nil:
case dns.TypeA, dns.TypeAAAA:
serv.Host = msg.Domain(serv.Key)
records = append(records, serv.NewMX(state.QName()))
extra = append(extra, serv.NewA(serv.Host, ip.To4()))
case ip.To4() == nil:
serv.Host = msg.Domain(serv.Key)
records = append(records, serv.NewMX(state.QName()))
extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
extra = append(extra, newAddress(serv, serv.Host, ip, what))
}
}
return records, extra, debug, nil
@ -360,18 +362,15 @@ func NS(b ServiceBackend, zone string, state request.Request, opt Options) (reco
state.Req.Question[0].Name = old
for _, serv := range services {
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
what, ip := serv.HostType()
switch what {
case dns.TypeANY:
return nil, nil, debug, fmt.Errorf("NS record must be an IP address: %s", serv.Host)
case ip.To4() != nil:
case dns.TypeA, dns.TypeAAAA:
serv.Host = msg.Domain(serv.Key)
records = append(records, serv.NewNS(state.QName()))
extra = append(extra, serv.NewA(serv.Host, ip.To4()))
case ip.To4() == nil:
serv.Host = msg.Domain(serv.Key)
records = append(records, serv.NewNS(state.QName()))
extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
extra = append(extra, newAddress(serv, serv.Host, ip, what))
}
}
return records, extra, debug, nil
@ -445,6 +444,17 @@ func ErrorToTxt(err error) dns.RR {
return t
}
func newAddress(s msg.Service, name string, ip net.IP, what uint16) dns.RR {
hdr := dns.RR_Header{Name: name, Rrtype: what, Class: dns.ClassINET, Ttl: s.TTL}
if what == dns.TypeA {
return &dns.A{Hdr: hdr, A: ip}
}
// Should always be dns.TypeAAAA
return &dns.AAAA{Hdr: hdr, AAAA: ip}
}
const (
minTTL = 60
hostmaster = "hostmaster"