Chore: IpToAddr

common/nnip/netip.go

@@ -0,0 +1,53 @@
+package nnip
+
+import (
+	"encoding/binary"
+	"net"
+	"net/netip"
+)
+
+// IpToAddr converts the net.IP to netip.Addr.
+// If slice's length is not 4 or 16, IpToAddr returns netip.Addr{}
+func IpToAddr(slice net.IP) netip.Addr {
+	ip := slice
+	if len(ip) != 4 {
+		if ip = slice.To4(); ip == nil {
+			ip = slice
+		}
+	}
+
+	if addr, ok := netip.AddrFromSlice(ip); ok {
+		return addr
+	}
+	return netip.Addr{}
+}
+
+// UnMasked returns p's last IP address.
+// If p is invalid, UnMasked returns netip.Addr{}
+func UnMasked(p netip.Prefix) netip.Addr {
+	if !p.IsValid() {
+		return netip.Addr{}
+	}
+
+	buf := p.Addr().As16()
+
+	hi := binary.BigEndian.Uint64(buf[:8])
+	lo := binary.BigEndian.Uint64(buf[8:])
+
+	bits := p.Bits()
+	if bits <= 32 {
+		bits += 96
+	}
+
+	hi = hi | ^uint64(0)>>bits
+	lo = lo | ^(^uint64(0) << (128 - bits))
+
+	binary.BigEndian.PutUint64(buf[:8], hi)
+	binary.BigEndian.PutUint64(buf[8:], lo)
+
+	addr := netip.AddrFrom16(buf)
+	if p.Addr().Is4() {
+		return addr.Unmap()
+	}
+	return addr
+}