Print NIC hardware address

It helps with debugging in case if a host has multiple network cards

Issue #155

init/network.go

@@ -93,11 +93,19 @@ func shutdownNetwork() {
 var initializedIfnames []string
 
 func initializeNetworkInterface(ifname string) error {
-	debug("%s: start initializing network interface", ifname)
 	link, err := netlink.LinkByName(ifname)
 	if err != nil {
 		return err
 	}
+	hardwareAddr := link.Attrs().HardwareAddr
+	debug("detected network interface %s (%s)", ifname, hardwareAddr)
+
+	if len(config.Network.Interfaces) > 0 {
+		if !macListContains(hardwareAddr, config.Network.Interfaces) {
+			info("interface %s (%s) is not in 'active' list, skipping it", ifname, hardwareAddr)
+			return nil
+		}
+	}
 
 	ch := make(chan netlink.LinkUpdate)
 	done := make(chan struct{})

init/udev.go

@@ -3,7 +3,6 @@ package main
 import (
 	"fmt"
 	"io"
-	"net"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -123,18 +122,6 @@ func handleNetworkUevent(ev *uevent.Uevent) error {
 		return nil
 	}
 
-	if len(config.Network.Interfaces) > 0 {
-		i, err := net.InterfaceByName(ifname)
-		if err != nil {
-			return err
-		}
-
-		if !macListContains(i.HardwareAddr, config.Network.Interfaces) {
-			info("interface %s is not in 'active' list, skipping it", ifname)
-			return nil
-		}
-	}
-
 	return initializeNetworkInterface(ifname)
 }