Messaging service, adapters, refactoring

pkg/discovery/packet.go

@@ -0,0 +1,26 @@
+package discovery
+
+import (
+	"bytes"
+	"net"
+)
+
+var magicBytes = []byte{0x01, 0x02, 0x01}
+
+func NewPacket() Packet {
+	return make(Packet, 7) // 7 = 3 bytes of magic + 4 bytes for ipv4 address
+}
+
+func NewPacketWithIP(ip net.IP) Packet {
+	return append(magicBytes, []byte(ip.To4())...)
+}
+
+type Packet []byte
+
+func (p Packet) IP(n int) net.IP {
+	return net.IP(p[3:n])
+}
+
+func (p Packet) MagicOk() bool {
+	return bytes.Equal(p[:3], magicBytes)
+}