dev

server/utils/raw_packet_send.go

@@ -0,0 +1,95 @@
+package utils
+
+import (
+        "log"
+        "net"
+        "unicode/utf8"
+
+        "github.com/google/gopacket"
+        "github.com/google/gopacket/layers"
+        "github.com/mdlayher/packet"
+)
+
+type SocketCall struct {
+        conn    *packet.Conn
+        Iface   *net.Interface
+}
+
+func splitData(message string) []string {
+        data := []string{}
+
+        var i, j int
+
+        for i, j = 0, 1458; j < len(message); i, j = j, j+1458 {
+                for !utf8.RuneStart(message[j]) {
+                        j--
+                }
+                data = append(data, message[i:j])
+        }
+        data = append(data, message[i:])
+
+        return data
+}
+
+func (c* SocketCall)SendData(message string) {
+        splitMessage := splitData(message)
+
+        for i := 0; i < len(splitMessage); i++ {
+                c.init(splitMessage[i])
+        }
+        return
+}
+
+func (c* SocketCall)init(data string) {
+        iface, _ := net.InterfaceByName("virbr0")
+        conn, err := packet.Listen(iface, packet.Raw, int(layers.EthernetTypeIPv4), nil)
+
+        payload := []byte(data)
+        if len(payload) > 1500 {
+                log.Printf("Larger than 1500 -- %d", len(payload))
+        }
+
+        if err != nil {
+                log.Panic(err)
+        }
+
+        c.Iface = iface
+        c.conn = conn
+
+        eth := layers.Ethernet{
+                EthernetType: layers.EthernetTypeIPv4,
+                SrcMAC:       c.Iface.HardwareAddr,
+                DstMAC:       layers.EthernetBroadcast,
+        }
+        ip := layers.IPv4{
+                Version:  4,
+                TTL:      64,
+                SrcIP:    []byte{0, 0, 0, 0},
+                DstIP:    []byte{255, 255, 255, 255},
+                Protocol: layers.IPProtocolUDP,
+        }
+        udp := layers.UDP{
+                SrcPort: 6868,
+                DstPort: 6767,
+        }
+
+        buf := gopacket.NewSerializeBuffer()
+        opts := gopacket.SerializeOptions{
+                ComputeChecksums: true,
+                FixLengths:       true,
+        }
+
+        udp.SetNetworkLayerForChecksum(&ip)
+        err = gopacket.SerializeLayers(buf, opts, &eth, &ip, &udp, gopacket.Payload(payload))
+        if err != nil {
+                log.Panic(err)
+        }
+
+        _, err = c.conn.WriteTo(buf.Bytes(), &packet.Addr{HardwareAddr: eth.DstMAC})
+        if err != nil {
+                log.Panic(err)
+        }
+
+        return
+}
+