1 files changed, 120 insertions, 0 deletions
diff --git a/middleware/kubernetes/parse.go b/middleware/kubernetes/parse.go
new file mode 100644
index 000000000..790060896
--- /dev/null
+++ b/middleware/kubernetes/parse.go
@@ -0,0 +1,120 @@
+package kubernetes
+
+import (
+	"github.com/coredns/coredns/middleware/pkg/dnsutil"
+
+	"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
+}
+
+// TODO(miek): make it use request.Request.
+func (k *Kubernetes) parseRequest(lowerCasedName string, qtype uint16, zone ...string) (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
+
+	if len(zone) == 0 {
+		panic("parseRequest must be called with a zone")
+	}
+
+	base, _ := dnsutil.TrimZone(lowerCasedName, zone[0])
+	segs := dns.SplitDomainName(base)
+
+	r.zone = zone[0]
+	r.federation, segs = k.stripFederation(segs)
+
+	if qtype == dns.TypeNS {
+		return r, nil
+	}
+
+	if qtype == dns.TypeA && isDefaultNS(lowerCasedName, r) {
+		return r, nil
+	}
+
+	offset := 0
+	if 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 (qtype == dns.TypeA || 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
+}