new: updated mac vendor lookup with IEEE datasets

network/manuf.go.template

@@ -1,28 +1,21 @@
 package network
 
 import (
-    "fmt"
 	"strings"
-    "math/big"
 )
 
 var manuf = #MAP#
 
 func ManufLookup(mac string) string {
-    macHex := strings.Replace(mac, ":", "", -1)
-    macInt := new(big.Int)
+	macHex := strings.ToUpper(strings.Replace(mac, ":", "", -1))
+	macLen := len(macHex)
 
-    if _, ok := macInt.SetString(macHex, 16); ok == false {
-        return ""
-    }
-
-    for mask := uint(0); mask < 48; mask++ {
-        shifted := new(big.Int).Rsh(macInt, mask)
-        key := fmt.Sprintf("%d.%s", mask, shifted)
-        if vendor, found := manuf[key]; found {
-            return vendor
-        }   
-    }
+	for offset := macLen; offset >= 2; offset -= 2 {
+		part := macHex[0:offset]
+		if vendor, found := manuf[part]; found {
+			return vendor
+		}
+	}
 
 	return ""
-}
+}