chinaip

common/net/ipnet.go

@@ -0,0 +1,97 @@
+package net
+
+import (
+	"net"
+)
+
+var (
+	onesCount = make(map[byte]byte)
+)
+
+type IPNet struct {
+	cache map[uint32]byte
+}
+
+func NewIPNet() *IPNet {
+	return NewIPNetInitialValue(make(map[uint32]byte, 1024))
+}
+
+func NewIPNetInitialValue(data map[uint32]byte) *IPNet {
+	return &IPNet{
+		cache: data,
+	}
+}
+
+func ipToUint32(ip net.IP) uint32 {
+	value := uint32(0)
+	for _, b := range []byte(ip) {
+		value <<= 8
+		value += uint32(b)
+	}
+	return value
+}
+
+func ipMaskToByte(mask net.IPMask) byte {
+	value := byte(0)
+	for _, b := range []byte(mask) {
+		value += onesCount[b]
+	}
+	return value
+}
+
+func (this *IPNet) Add(ipNet *net.IPNet) {
+	ipv4 := ipNet.IP.To4()
+	if ipv4 == nil {
+		// For now, we don't support IPv6
+		return
+	}
+	value := ipToUint32(ipv4)
+	mask := ipMaskToByte(ipNet.Mask)
+	existing, found := this.cache[value]
+	if !found || existing > mask {
+		this.cache[value] = mask
+	}
+}
+
+func (this *IPNet) Contains(ip net.IP) bool {
+	ipv4 := ip.To4()
+	if ipv4 == nil {
+		return false
+	}
+	originalValue := ipToUint32(ipv4)
+
+	if entry, found := this.cache[originalValue]; found {
+		if entry == 0 {
+			return true
+		}
+	}
+
+	mask := uint32(0)
+	for maskbit := byte(1); maskbit <= 32; maskbit++ {
+		mask += 1 << uint32(32-maskbit)
+
+		maskedValue := originalValue & mask
+		if entry, found := this.cache[maskedValue]; found {
+			if entry == maskbit {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func (this *IPNet) Serialize() []uint32 {
+	content := make([]uint32, 0, 2*len(this.cache))
+	for key, value := range this.cache {
+		content = append(content, uint32(key), uint32(value))
+	}
+	return content
+}
+
+func init() {
+	value := byte(0)
+	for mask := byte(1); mask <= 8; mask++ {
+		value += 1 << byte(8-mask)
+		onesCount[value] = mask
+	}
+}