Create controlplane API to enable HA CloudAgent without FailOver Clus…

…ter (#12)

* add cloudagent/cloud/controlplane API

* update cloudagent/cloud/controlplane API

* use ip instead of fqdn

* enable dhcp and static ip addresses to coexist

* use fqdn rather than ip and remove isLeader

* avoid introducing new dependencies on moc-pkg

* add netsh command for deleting ip address (it works when PS command fails)

* move code to staticip in moc-pkg

* remove certificate and authport

* add state parameter to controlplane to track active/leader/unknown

* currently only exposing leader/nonleader

* retrieve the network interface corresponding to getipaddress

* fix typo

* rename type conversion variable

* add comments to controlplane proto

pkg/net/net.go

@@ -3,6 +3,7 @@
 package net
 
 import (
+	"fmt"
 	"math/big"
 	"net"
 )
@@ -111,3 +112,56 @@ func PrefixesOverlap(cidr1 net.IPNet, cidr2 net.IPNet) bool {
 	}
 	return false
 }
+
+func GetNetworkInterface() (string, error) {
+	// get primary public IP address
+	primaryPublicIP, err := GetIPAddress()
+	if err != nil {
+		return "", err
+	}
+
+	networkInterfaces, err := net.Interfaces()
+	if err != nil {
+		return "", err
+	}
+
+	for _, networkInterface := range networkInterfaces {
+		// return this interface iff it contains the
+		// primary public IP address
+
+		// skip down interface
+		if networkInterface.Flags&net.FlagUp == 0 {
+			continue
+		}
+		// skip loopback
+		if networkInterface.Flags&net.FlagLoopback != 0 {
+			continue
+		}
+		// list of unicast interface addresses for specific interface
+		addresses, err := networkInterface.Addrs()
+		if err != nil {
+			return "", err
+		}
+		// network end point address
+		for _, address := range addresses {
+			var ip net.IP
+			switch typedAddress := address.(type) {
+			case *net.IPNet:
+				ip = typedAddress.IP
+			case *net.IPAddr:
+				ip = typedAddress.IP
+			}
+			// skip loopback or wrong type
+			if ip == nil || ip.IsLoopback() {
+				continue
+			}
+
+			if ip.String() == primaryPublicIP {
+				// return this interface
+				return networkInterface.Name, nil
+			}
+		}
+	}
+
+	return "", fmt.Errorf("No network interfaces found")
+}