forked from coredns/coredns
/
ns.go
65 lines (54 loc) · 1.35 KB
/
ns.go
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package kubernetes
import (
"net"
"strings"
"github.com/miekg/dns"
api "k8s.io/api/core/v1"
)
func isDefaultNS(name, zone string) bool {
return strings.Index(name, defaultNSName) == 0 && strings.Index(name, zone) == len(defaultNSName)
}
// nsAddr return the A record for the CoreDNS service in the cluster. If it fails that it fallsback
// on the local address of the machine we're running on.
//
// This function is rather expensive to run.
func (k *Kubernetes) nsAddr() *dns.A {
var (
svcName string
svcNamespace string
)
rr := new(dns.A)
localIP := k.interfaceAddrsFunc()
rr.A = localIP
FindEndpoint:
for _, ep := range k.APIConn.EpIndexReverse(localIP.String()) {
for _, eps := range ep.Subsets {
for _, addr := range eps.Addresses {
if localIP.Equal(net.ParseIP(addr.IP)) {
svcNamespace = ep.Namespace
svcName = ep.Name
break FindEndpoint
}
}
}
}
if len(svcName) == 0 {
rr.Hdr.Name = defaultNSName
rr.A = localIP
return rr
}
FindService:
for _, svc := range k.APIConn.ServiceList() {
if svcName == svc.Name && svcNamespace == svc.Namespace {
if svc.ClusterIP == api.ClusterIPNone {
rr.A = localIP
} else {
rr.A = net.ParseIP(svc.ClusterIP)
}
break FindService
}
}
rr.Hdr.Name = strings.Join([]string{svcName, svcNamespace, "svc."}, ".")
return rr
}
const defaultNSName = "ns.dns."