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package kubernetes
import (
"github.com/coredns/coredns/middleware/pkg/dnsutil"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
type recordRequest struct {
// The named port from the kubernetes DNS spec, this is the service part (think _https) from a well formed
// SRV record.
port string
// The protocol is usually _udp or _tcp (if set), and comes from the protocol part of a well formed
// SRV record.
protocol string
endpoint string
service string
namespace string
// A each name can be for a pod or a service, here we track what we've seen. This value is true for
// pods and false for services. If we ever need to extend this well use a typed value.
podOrSvc string
zone string
federation string
}
// parseRequest parses the qname to find all the elements we need for querying k8s.
func (k *Kubernetes) parseRequest(state request.Request) (r recordRequest, err error) {
// 3 Possible cases
// SRV Request: _port._protocol.service.namespace.[federation.]type.zone
// A Request (endpoint): endpoint.service.namespace.[federation.]type.zone
// A Request (service): service.namespace.[federation.]type.zone
base, _ := dnsutil.TrimZone(state.Name(), state.Zone)
segs := dns.SplitDomainName(base)
r.zone = state.Zone
r.federation, segs = k.stripFederation(segs)
if state.QType() == dns.TypeNS {
return r, nil
}
if state.QType() == dns.TypeA && isDefaultNS(state.Name(), r) {
return r, nil
}
offset := 0
if state.QType() == dns.TypeSRV {
// The kubernetes peer-finder expects queries with empty port and service to resolve
// If neither is specified, treat it as a wildcard
if len(segs) == 3 {
r.port = "*"
r.service = "*"
offset = 0
} else {
if len(segs) != 5 {
return r, errInvalidRequest
}
// This is a SRV style request, get first two elements as port and
// protocol, stripping leading underscores if present.
if segs[0][0] == '_' {
r.port = segs[0][1:]
} else {
r.port = segs[0]
if !wildcard(r.port) {
return r, errInvalidRequest
}
}
if segs[1][0] == '_' {
r.protocol = segs[1][1:]
if r.protocol != "tcp" && r.protocol != "udp" {
return r, errInvalidRequest
}
} else {
r.protocol = segs[1]
if !wildcard(r.protocol) {
return r, errInvalidRequest
}
}
if r.port == "" || r.protocol == "" {
return r, errInvalidRequest
}
offset = 2
}
}
if (state.QType() == dns.TypeA || state.QType() == dns.TypeAAAA) && len(segs) == 4 {
// This is an endpoint A/AAAA record request. Get first element as endpoint.
r.endpoint = segs[0]
offset = 1
}
if len(segs) == (offset + 3) {
r.service = segs[offset]
r.namespace = segs[offset+1]
r.podOrSvc = segs[offset+2]
return r, nil
}
return r, errInvalidRequest
}
// String return a string representation of r, it just returns all
// fields concatenated with dots.
// This is mostly used in tests.
func (r recordRequest) String() string {
s := r.port
s += "." + r.protocol
s += "." + r.endpoint
s += "." + r.service
s += "." + r.namespace
s += "." + r.podOrSvc
s += "." + r.zone
s += "." + r.federation
return s
}
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