further updates

server/utils/file_transfer.go

@@ -0,0 +1,39 @@
+package utils
+
+import (
+	"log"
+	"github.com/google/gopacket"
+
+	"saprusserver/structs"
+)
+
+func (c* SocketCall) FileTransferPacket(message string) gopacket.SerializeBuffer {
+        eth, ip, udp := basePacket(c)
+
+        sapFile := structs.SaprusFileTransfer {
+                Flag:           [1]byte{0x11},
+                Sequence:       [2]byte{0x22, 0x33},
+                Checksum:       [2]byte{0x44, 0x44},
+                Payload:        []byte(message),
+        }
+
+        sapHeader := structs.SaprusHeaderFrame {
+                PacketType:     [2]byte{0x88, 0x88},
+                Length:         c.saprusPayloadLength(sapFile.Bytes()),
+                Payload:        sapFile.Bytes(),
+        }
+
+        buf := gopacket.NewSerializeBuffer()
+        opts := gopacket.SerializeOptions {
+                ComputeChecksums:       true,
+                FixLengths:             true,
+        }
+
+        udp.SetNetworkLayerForChecksum(&ip)
+        err := gopacket.SerializeLayers(buf, opts, &eth, &ip, &udp, gopacket.Payload(sapHeader.Bytes()))
+        if err != nil {
+                log.Panic(err)
+        }
+        return buf
+}
+

server/utils/packet_helper.go

@@ -0,0 +1,27 @@
+package utils
+
+import (
+	"github.com/google/gopacket/layers"
+)
+
+func basePacket(c* SocketCall) (layers.Ethernet, layers.IPv4, layers.UDP) {
+        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,
+        }
+
+        return eth, ip, udp
+}
+

server/utils/raw_packet_send.go

@@ -68,6 +68,7 @@ func (c* SocketCall) saprusPayloadLength(pkt []byte) [2]byte{
 	return length
 }
 
+/*
 func (c* SocketCall)init(data string) {
         iface, _ := net.InterfaceByName("virbr0")
         conn, err := packet.Listen(iface, packet.Raw, int(layers.EthernetTypeIPv4), nil)
@@ -96,7 +97,6 @@ func (c* SocketCall)init(data string) {
                 DstPort: 6767,
         }
 
-	// FUCK THIS
 	saprusPayloadLength := make([]byte, 2)
 	binary.BigEndian.PutUint16(saprusPayloadLength, uint16(len(data)))
 	var saprusPayloadLengthTwo [2]byte
@@ -128,4 +128,4 @@ func (c* SocketCall)init(data string) {
 
         return
 }
-
+*/