Add tests for dns snooper.

probe/endpoint/dns_snooper_test.go

@@ -0,0 +1,74 @@
+// +build linux,amd64 linux,ppc64le
+package endpoint
+
+import (
+	"net"
+	"testing"
+
+	"github.com/google/gopacket/layers"
+)
+
+func TestprocessDNSMessageMultipleCNAME(t *testing.T) {
+	domain := "dummy.com"
+	question := layers.DNSQuestion{
+		Name: []byte(domain),
+		Type: layers.DNSTypeA,
+	}
+
+	ipAddressCNAME := "127.0.0.1"
+	ipAddress := "127.0.1.1"
+	answers := []layers.DNSResourceRecord{
+		layers.DNSResourceRecord{
+			Name:  []byte("api.dummy.com"),
+			Type:  layers.DNSTypeCNAME,
+			Class: layers.DNSClassIN,
+		},
+		layers.DNSResourceRecord{
+			Name:  []byte("star.c10r.dummy.com"),
+			Type:  layers.DNSTypeCNAME,
+			Class: layers.DNSClassIN,
+		},
+		layers.DNSResourceRecord{
+			Name:  []byte("dummy.com"),
+			Type:  layers.DNSTypeA,
+			Class: layers.DNSClassIN,
+			IP:    net.ParseIP(ipAddress),
+		},
+		layers.DNSResourceRecord{
+			Name:  []byte("star.c10r.dummy.com"),
+			Type:  layers.DNSTypeA,
+			Class: layers.DNSClassIN,
+			IP:    net.ParseIP(ipAddressCNAME),
+		},
+	}
+
+	dns := layers.DNS{
+		ResponseCode: layers.DNSResponseCodeNoErr,
+		Questions:    []layers.DNSQuestion{question},
+		Answers:      answers,
+	}
+
+	snooper := &DNSSnooper{}
+
+	snooper.processDNSMessage(&dns)
+
+	existingDomains, err := snooper.reverseDNSCache.Get(ipAddressCNAME)
+
+	if err != nil {
+		t.Errorf("A domain should have been inserted for the given CNAME IP:%v", err)
+	}
+
+	if _, ok := existingDomains.(map[string]struct{})[domain]; !ok {
+		t.Errorf("Domain %s should have been inserted", domain)
+	}
+
+	existingDomains, err = snooper.reverseDNSCache.Get(ipAddress)
+
+	if err != nil {
+		t.Errorf("A domain should have been inserted for the given IP:%v", err)
+	}
+
+	if _, ok := existingDomains.(map[string]struct{})[domain]; !ok {
+		t.Errorf("Domain %s should have been inserted", domain)
+	}
+}