coredns/middleware/etcd/lookup.go
Miek Gieben e62eb2cde0 Bugfix: bx in etcd.go didn't get Key
Thus record only diffing in the Key were seen as identical and not
included in the end results. Of course this being a map when and if
this would happen was rather random.

Fixed by including Key. Further small tweaks and code refactors.
2016-03-25 15:30:44 +00:00

342 lines
9.1 KiB
Go

package etcd
import (
"math"
"net"
"github.com/miekg/coredns/middleware"
"github.com/miekg/coredns/middleware/etcd/msg"
"github.com/miekg/dns"
)
func (e Etcd) records(state middleware.State, exact bool) ([]msg.Service, error) {
services, err := e.Records(state.Name(), exact)
if err != nil {
return nil, err
}
services = msg.Group(services)
return services, nil
}
func (e Etcd) A(zone string, state middleware.State, previousRecords []dns.RR) (records []dns.RR, err error) {
services, err := e.records(state, false)
if err != nil {
return nil, 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.
// TODO(miek): lowercasing, use Match in middleware?
if state.Name() == 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 := e.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 := 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
case ip.To4() != nil:
records = append(records, serv.NewA(state.QName(), ip.To4()))
case ip.To4() == nil:
// noda?
}
}
return records, nil
}
func (e Etcd) AAAA(zone string, state middleware.State, previousRecords []dns.RR) (records []dns.RR, err error) {
services, err := e.records(state, false)
if err != nil {
return nil, 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.
// TODO(miek): lowercasing, use Match in middleware/
if state.Name() == 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 := 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 {
// TODO(miek): sorting here?
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 := 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, 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 []dns.RR, extra []dns.RR, err error) {
services, err := e.records(state, false)
if err != nil {
return 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, e1 := e.A(zone, state1, nil)
if e1 == nil {
extra = append(extra, addr...)
}
// e.AAA(zone, state1, nil) as well...?
case ip.To4() != nil:
serv.Host = e.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 = e.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, 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 []dns.RR, extra []dns.RR, err error) {
services, err := e.records(state, false)
if err != nil {
return nil, nil, 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, e1 := e.A(zone, state1, nil)
if e1 == nil {
extra = append(extra, addr...)
}
// e.AAAA as well
case ip.To4() != nil:
serv.Host = e.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 = e.Domain(serv.Key)
records = append(records, serv.NewMX(state.QName()))
extra = append(extra, serv.NewAAAA(serv.Host, ip.To16()))
}
}
return records, extra, nil
}
func (e Etcd) CNAME(zone string, state middleware.State) (records []dns.RR, err error) {
services, err := e.records(state, true)
if err != nil {
return nil, 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, nil
}
func (e Etcd) TXT(zone string, state middleware.State) (records []dns.RR, err error) {
services, err := e.records(state, false)
if err != nil {
return nil, err
}
for _, serv := range services {
if serv.Text == "" {
continue
}
records = append(records, serv.NewTXT(state.QName()))
}
return records, nil
}
// synthesis a SOA Record.
// TODO(miek): finish
func (e Etcd) SOA(zone string, state middleware.State) *dns.SOA {
header := dns.RR_Header{Name: zone, Rrtype: dns.TypeSOA, Ttl: 300, Class: dns.ClassINET}
return &dns.SOA{Hdr: header, Mbox: "hostmaster." + zone, Ns: "ns.dns." + zone}
}
// TODO(miek): NS records, DS and DNSKEY ones...? prolly so that the signing will
// work...
func isDuplicateCNAME(r *dns.CNAME, records []dns.RR) bool {
for _, rec := range records {
if v, ok := rec.(*dns.CNAME); ok {
if v.Target == r.Target {
return true
}
}
}
return false
}
func copyState(state middleware.State, target string, typ uint16) middleware.State {
state1 := middleware.State{W: state.W, Req: state.Req.Copy()}
state1.Req.Question[0] = dns.Question{dns.Fqdn(target), dns.ClassINET, typ}
return state1
}