func (c Chaos) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := middleware.State{W: w, Req: r}
if state.QClass() != dns.ClassCHAOS || state.QType() != dns.TypeTXT {
return c.Next.ServeDNS(ctx, w, r)
}
m := new(dns.Msg)
m.SetReply(r)
hdr := dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeTXT, Class: dns.ClassCHAOS, Ttl: 0}
switch state.Name() {
default:
return c.Next.ServeDNS(ctx, w, r)
case "authors.bind.":
for a, _ := range c.Authors {
m.Answer = append(m.Answer, &dns.TXT{Hdr: hdr, Txt: []string{trim(a)}})
}
case "version.bind.", "version.server.":
m.Answer = []dns.RR{&dns.TXT{Hdr: hdr, Txt: []string{trim(c.Version)}}}
case "hostname.bind.", "id.server.":
hostname, err := os.Hostname()
if err != nil {
hostname = "localhost"
}
m.Answer = []dns.RR{&dns.TXT{Hdr: hdr, Txt: []string{trim(hostname)}}}
}
state.SizeAndDo(m)
w.WriteMsg(m)
return 0, nil
}
func (e Etcd) AAAA(zone string, state middleware.State, previousRecords []dns.RR) (records []dns.RR, debug []msg.Service, err error) {
services, debug, err := e.records(state, false)
if err != nil {
return nil, debug, err
}
for _, serv := range services {
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
// Try to resolve as CNAME if it's not an IP, but only if we don't create loops.
if middleware.Name(state.Name()).Matches(dns.Fqdn(serv.Host)) {
// x CNAME x is a direct loop, don't add those
continue
}
newRecord := serv.NewCNAME(state.QName(), serv.Host)
if len(previousRecords) > 7 {
// don't add it, and just continue
continue
}
if isDuplicateCNAME(newRecord, previousRecords) {
continue
}
state1 := copyState(state, serv.Host, state.QType())
nextRecords, nextDebug, err := e.AAAA(zone, state1, append(previousRecords, newRecord))
if err == nil {
// Not only have we found something we should add the CNAME and the IP addresses.
if len(nextRecords) > 0 {
records = append(records, newRecord)
records = append(records, nextRecords...)
debug = append(debug, nextDebug...)
}
continue
}
// This means we can not complete the CNAME, try to look else where.
target := newRecord.Target
if dns.IsSubDomain(zone, target) {
// We should already have found it
continue
}
m1, e1 := e.Proxy.Lookup(state, target, state.QType())
if e1 != nil {
continue
}
// Len(m1.Answer) > 0 here is well?
records = append(records, newRecord)
records = append(records, m1.Answer...)
continue
// both here again
case ip.To4() != nil:
// nada?
case ip.To4() == nil:
records = append(records, serv.NewAAAA(state.QName(), ip.To16()))
}
}
return records, debug, nil
}
func (k Kubernetes) A(zone string, state middleware.State, previousRecords []dns.RR) (records []dns.RR, err error) {
services, err := k.records(state, false)
if err != nil {
return nil, err
}
for _, serv := range services {
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
// TODO(miek): lowercasing? Should lowercase in everything see #85
if middleware.Name(state.Name()).Matches(dns.Fqdn(serv.Host)) {
// x CNAME x is a direct loop, don't add those
continue
}
newRecord := serv.NewCNAME(state.QName(), serv.Host)
if len(previousRecords) > 7 {
// don't add it, and just continue
continue
}
if isDuplicateCNAME(newRecord, previousRecords) {
continue
}
state1 := copyState(state, serv.Host, state.QType())
nextRecords, err := k.A(zone, state1, append(previousRecords, newRecord))
if err == nil {
// Not only have we found something we should add the CNAME and the IP addresses.
if len(nextRecords) > 0 {
records = append(records, newRecord)
records = append(records, nextRecords...)
}
continue
}
// This means we can not complete the CNAME, try to look else where.
target := newRecord.Target
if dns.IsSubDomain(zone, target) {
// We should already have found it
continue
}
m1, e1 := k.Proxy.Lookup(state, target, state.QType())
if e1 != nil {
continue
}
// Len(m1.Answer) > 0 here is well?
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:
// nodata?
}
}
return records, nil
}
// PTR returns the PTR records, only services that have a domain name as host are included.
func (e Etcd) PTR(zone string, state middleware.State) (records []dns.RR, debug []msg.Service, err error) {
services, debug, err := e.records(state, true)
if err != nil {
return nil, debug, err
}
for _, serv := range services {
if ip := net.ParseIP(serv.Host); ip == nil {
records = append(records, serv.NewPTR(state.QName(), serv.Host))
}
}
return records, debug, nil
}
func (e Etcd) TXT(zone string, state middleware.State) (records []dns.RR, debug []msg.Service, err error) {
services, debug, err := e.records(state, false)
if err != nil {
return nil, debug, err
}
for _, serv := range services {
if serv.Text == "" {
continue
}
records = append(records, serv.NewTXT(state.QName()))
}
return records, debug, nil
}
func (e Etcd) CNAME(zone string, state middleware.State) (records []dns.RR, debug []msg.Service, err error) {
services, debug, err := e.records(state, true)
if err != nil {
return nil, debug, err
}
if len(services) > 0 {
serv := services[0]
if ip := net.ParseIP(serv.Host); ip == nil {
records = append(records, serv.NewCNAME(state.QName(), serv.Host))
}
}
return records, debug, nil
}
func (m Metrics) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := middleware.State{W: w, Req: r}
qname := state.QName()
zone := middleware.Zones(m.ZoneNames).Matches(qname)
if zone == "" {
zone = "."
}
// Record response to get status code and size of the reply.
rw := middleware.NewResponseRecorder(w)
status, err := m.Next.ServeDNS(ctx, rw, r)
Report(state, zone, rw.Rcode(), rw.Size(), rw.Start())
return status, err
}
func (e Etcd) NS(zone string, state middleware.State) (records, extra []dns.RR, debug []msg.Service, err error) {
// NS record for this zone live in a special place, ns.dns.<zone>. Fake our lookup.
// only a tad bit fishy...
old := state.QName()
state.Clear()
state.Req.Question[0].Name = "ns.dns." + zone
services, debug, err := e.records(state, false)
if err != nil {
return nil, nil, debug, err
}
// ... and reset
state.Req.Question[0].Name = old
for _, serv := range services {
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
return nil, nil, debug, fmt.Errorf("NS record must be an IP address: %s", serv.Host)
case ip.To4() != nil:
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()))
}
}
return records, extra, debug, nil
}
// MX returns MX records from etcd.
// If the Target is not a name but an IP address, a name is created on the fly.
func (e Etcd) MX(zone string, state middleware.State) (records, extra []dns.RR, debug []msg.Service, err error) {
services, debug, err := e.records(state, false)
if err != nil {
return nil, nil, debug, err
}
lookup := make(map[string]bool)
for _, serv := range services {
if !serv.Mail {
continue
}
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
mx := serv.NewMX(state.QName())
records = append(records, mx)
if _, ok := lookup[mx.Mx]; ok {
break
}
lookup[mx.Mx] = true
if !dns.IsSubDomain(zone, mx.Mx) {
m1, e1 := e.Proxy.Lookup(state, mx.Mx, dns.TypeA)
if e1 == nil {
extra = append(extra, m1.Answer...)
}
m1, e1 = e.Proxy.Lookup(state, mx.Mx, dns.TypeAAAA)
if e1 == nil {
// If we have seen CNAME's we *assume* that they are already added.
for _, a := range m1.Answer {
if _, ok := a.(*dns.CNAME); !ok {
extra = append(extra, a)
}
}
}
break
}
// Internal name
state1 := copyState(state, mx.Mx, dns.TypeA)
addr, debugAddr, e1 := e.A(zone, state1, nil)
if e1 == nil {
extra = append(extra, addr...)
debug = append(debug, debugAddr...)
}
// e.AAAA as well
case ip.To4() != nil:
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()))
}
}
return records, extra, debug, nil
}
// SRV returns SRV records from etcd.
// If the Target is not a name but an IP address, a name is created on the fly.
func (e Etcd) SRV(zone string, state middleware.State) (records, extra []dns.RR, debug []msg.Service, err error) {
services, debug, err := e.records(state, false)
if err != nil {
return nil, nil, nil, err
}
// Looping twice to get the right weight vs priority
w := make(map[int]int)
for _, serv := range services {
weight := 100
if serv.Weight != 0 {
weight = serv.Weight
}
if _, ok := w[serv.Priority]; !ok {
w[serv.Priority] = weight
continue
}
w[serv.Priority] += weight
}
lookup := make(map[string]bool)
for _, serv := range services {
w1 := 100.0 / float64(w[serv.Priority])
if serv.Weight == 0 {
w1 *= 100
} else {
w1 *= float64(serv.Weight)
}
weight := uint16(math.Floor(w1))
ip := net.ParseIP(serv.Host)
switch {
case ip == nil:
srv := serv.NewSRV(state.QName(), weight)
records = append(records, srv)
if _, ok := lookup[srv.Target]; ok {
break
}
lookup[srv.Target] = true
if !dns.IsSubDomain(zone, srv.Target) {
m1, e1 := e.Proxy.Lookup(state, srv.Target, dns.TypeA)
if e1 == nil {
extra = append(extra, m1.Answer...)
}
m1, e1 = e.Proxy.Lookup(state, srv.Target, dns.TypeAAAA)
if e1 == nil {
// If we have seen CNAME's we *assume* that they are already added.
for _, a := range m1.Answer {
if _, ok := a.(*dns.CNAME); !ok {
extra = append(extra, a)
}
}
}
break
}
// Internal name, we should have some info on them, either v4 or v6
// Clients expect a complete answer, because we are a recursor in their view.
state1 := copyState(state, srv.Target, dns.TypeA)
addr, debugAddr, e1 := e.A(zone, state1, nil)
if e1 == nil {
extra = append(extra, addr...)
debug = append(debug, debugAddr...)
}
// e.AAA(zone, state1, nil) as well...?
case ip.To4() != nil:
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()))
}
}
return records, extra, debug, nil
}
