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package azure
import (
"context"
"fmt"
"net"
"sync"
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/file"
"github.com/coredns/coredns/plugin/pkg/fall"
"github.com/coredns/coredns/plugin/pkg/upstream"
"github.com/coredns/coredns/request"
azuredns "github.com/Azure/azure-sdk-for-go/profiles/latest/dns/mgmt/dns"
"github.com/miekg/dns"
)
type zone struct {
id string
z *file.Zone
zone string
}
type zones map[string][]*zone
// Azure is the core struct of the azure plugin.
type Azure struct {
zoneNames []string
client azuredns.RecordSetsClient
upstream *upstream.Upstream
zMu sync.RWMutex
zones zones
Next plugin.Handler
Fall fall.F
}
// New validates the input DNS zones and initializes the Azure struct.
func New(ctx context.Context, dnsClient azuredns.RecordSetsClient, keys map[string][]string) (*Azure, error) {
zones := make(map[string][]*zone, len(keys))
names := make([]string, len(keys))
for resourceGroup, znames := range keys {
for _, name := range znames {
if _, err := dnsClient.ListAllByDNSZone(context.Background(), resourceGroup, name, nil, ""); err != nil {
return nil, err
}
fqdn := dns.Fqdn(name)
if _, ok := zones[fqdn]; !ok {
names = append(names, fqdn)
}
zones[fqdn] = append(zones[fqdn], &zone{id: resourceGroup, zone: fqdn, z: file.NewZone(fqdn, "")})
}
}
return &Azure{
client: dnsClient,
zones: zones,
zoneNames: names,
upstream: upstream.New(),
}, nil
}
// Run updates the zone from azure.
func (h *Azure) Run(ctx context.Context) error {
if err := h.updateZones(ctx); err != nil {
return err
}
go func() {
for {
select {
case <-ctx.Done():
log.Infof("Breaking out of Azure update loop: %v", ctx.Err())
return
case <-time.After(1 * time.Minute):
if err := h.updateZones(ctx); err != nil && ctx.Err() == nil {
log.Errorf("Failed to update zones: %v", err)
}
}
}
}()
return nil
}
func (h *Azure) updateZones(ctx context.Context) error {
errs := make([]string, 0)
for zName, z := range h.zones {
for i, hostedZone := range z {
recordSet, err := h.client.ListByDNSZone(ctx, hostedZone.id, hostedZone.zone, nil, "")
if err != nil {
errs = append(errs, fmt.Sprintf("failed to list resource records for %v from azure: %v", hostedZone.zone, err))
}
newZ := updateZoneFromResourceSet(recordSet, zName)
newZ.Upstream = h.upstream
h.zMu.Lock()
(*z[i]).z = newZ
h.zMu.Unlock()
}
}
if len(errs) != 0 {
return fmt.Errorf("errors updating zones: %v", errs)
}
return nil
}
func updateZoneFromResourceSet(recordSet azuredns.RecordSetListResultPage, zName string) *file.Zone {
newZ := file.NewZone(zName, "")
for _, result := range *(recordSet.Response().Value) {
resultFqdn := *(result.RecordSetProperties.Fqdn)
resultTTL := uint32(*(result.RecordSetProperties.TTL))
if result.RecordSetProperties.ARecords != nil {
for _, A := range *(result.RecordSetProperties.ARecords) {
a := &dns.A{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: resultTTL},
A: net.ParseIP(*(A.Ipv4Address))}
newZ.Insert(a)
}
}
if result.RecordSetProperties.AaaaRecords != nil {
for _, AAAA := range *(result.RecordSetProperties.AaaaRecords) {
aaaa := &dns.AAAA{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: resultTTL},
AAAA: net.ParseIP(*(AAAA.Ipv6Address))}
newZ.Insert(aaaa)
}
}
if result.RecordSetProperties.MxRecords != nil {
for _, MX := range *(result.RecordSetProperties.MxRecords) {
mx := &dns.MX{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeMX, Class: dns.ClassINET, Ttl: resultTTL},
Preference: uint16(*(MX.Preference)),
Mx: dns.Fqdn(*(MX.Exchange))}
newZ.Insert(mx)
}
}
if result.RecordSetProperties.PtrRecords != nil {
for _, PTR := range *(result.RecordSetProperties.PtrRecords) {
ptr := &dns.PTR{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypePTR, Class: dns.ClassINET, Ttl: resultTTL},
Ptr: dns.Fqdn(*(PTR.Ptrdname))}
newZ.Insert(ptr)
}
}
if result.RecordSetProperties.SrvRecords != nil {
for _, SRV := range *(result.RecordSetProperties.SrvRecords) {
srv := &dns.SRV{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeSRV, Class: dns.ClassINET, Ttl: resultTTL},
Priority: uint16(*(SRV.Priority)),
Weight: uint16(*(SRV.Weight)),
Port: uint16(*(SRV.Port)),
Target: dns.Fqdn(*(SRV.Target))}
newZ.Insert(srv)
}
}
if result.RecordSetProperties.TxtRecords != nil {
for _, TXT := range *(result.RecordSetProperties.TxtRecords) {
txt := &dns.TXT{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: resultTTL},
Txt: *(TXT.Value)}
newZ.Insert(txt)
}
}
if result.RecordSetProperties.NsRecords != nil {
for _, NS := range *(result.RecordSetProperties.NsRecords) {
ns := &dns.NS{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeNS, Class: dns.ClassINET, Ttl: resultTTL},
Ns: *(NS.Nsdname)}
newZ.Insert(ns)
}
}
if result.RecordSetProperties.SoaRecord != nil {
SOA := result.RecordSetProperties.SoaRecord
soa := &dns.SOA{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeSOA, Class: dns.ClassINET, Ttl: resultTTL},
Minttl: uint32(*(SOA.MinimumTTL)),
Expire: uint32(*(SOA.ExpireTime)),
Retry: uint32(*(SOA.RetryTime)),
Refresh: uint32(*(SOA.RefreshTime)),
Serial: uint32(*(SOA.SerialNumber)),
Mbox: dns.Fqdn(*(SOA.Email)),
Ns: *(SOA.Host)}
newZ.Insert(soa)
}
if result.RecordSetProperties.CnameRecord != nil {
CNAME := result.RecordSetProperties.CnameRecord.Cname
cname := &dns.CNAME{Hdr: dns.RR_Header{Name: resultFqdn, Rrtype: dns.TypeCNAME, Class: dns.ClassINET, Ttl: resultTTL},
Target: dns.Fqdn(*CNAME)}
newZ.Insert(cname)
}
}
return newZ
}
// ServeDNS implements the plugin.Handler interface.
func (h *Azure) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := request.Request{W: w, Req: r}
qname := state.Name()
zone := plugin.Zones(h.zoneNames).Matches(qname)
if zone == "" {
return plugin.NextOrFailure(h.Name(), h.Next, ctx, w, r)
}
zones, ok := h.zones[zone] // ok true if we are authoritative for the zone.
if !ok || zones == nil {
return dns.RcodeServerFailure, nil
}
m := new(dns.Msg)
m.SetReply(r)
m.Authoritative = true
var result file.Result
for _, z := range zones {
h.zMu.RLock()
m.Answer, m.Ns, m.Extra, result = z.z.Lookup(ctx, state, qname)
h.zMu.RUnlock()
// record type exists for this name (NODATA).
if len(m.Answer) != 0 || result == file.NoData {
break
}
}
if len(m.Answer) == 0 && result != file.NoData && h.Fall.Through(qname) {
return plugin.NextOrFailure(h.Name(), h.Next, ctx, w, r)
}
switch result {
case file.Success:
case file.NoData:
case file.NameError:
m.Rcode = dns.RcodeNameError
case file.Delegation:
m.Authoritative = false
case file.ServerFailure:
return dns.RcodeServerFailure, nil
}
w.WriteMsg(m)
return dns.RcodeSuccess, nil
}
// Name implements plugin.Handler.Name.
func (h *Azure) Name() string { return "azure" }
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