mirror of
https://github.com/bolkedebruin/rdpgw.git
synced 2025-08-17 05:53:50 +02:00
71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
package protocol
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"github.com/bolkedebruin/rdpgw/transport"
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"io"
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"log"
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"net"
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)
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func createPacket(pktType uint16, data []byte) (packet []byte) {
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size := len(data) + 8
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buf := new(bytes.Buffer)
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binary.Write(buf, binary.LittleEndian, uint16(pktType))
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binary.Write(buf, binary.LittleEndian, uint16(0)) // reserved
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binary.Write(buf, binary.LittleEndian, uint32(size))
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buf.Write(data)
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return buf.Bytes()
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}
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func readHeader(data []byte) (packetType uint16, size uint32, packet []byte, err error) {
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// header needs to be 8 min
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if len(data) < 8 {
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return 0, 0, nil, errors.New("header too short, fragment likely")
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}
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r := bytes.NewReader(data)
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binary.Read(r, binary.LittleEndian, &packetType)
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r.Seek(4, io.SeekStart)
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binary.Read(r, binary.LittleEndian, &size)
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if len(data) < int(size) {
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return packetType, size, data[8:], errors.New("data incomplete, fragment received")
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}
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return packetType, size, data[8:], nil
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}
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// sends data wrapped inside the rdpgw protocol
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func forward(in net.Conn, out transport.Transport) {
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defer in.Close()
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b1 := new(bytes.Buffer)
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buf := make([]byte, 4086)
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for {
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n, err := in.Read(buf)
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if err != nil {
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log.Printf("Error reading from local conn %s", err)
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break
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}
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binary.Write(b1, binary.LittleEndian, uint16(n))
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b1.Write(buf[:n])
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out.WritePacket(createPacket(PKT_TYPE_DATA, b1.Bytes()))
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b1.Reset()
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}
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}
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// receive data from the wire, unwrap and forward to the client
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func receive(data []byte, out net.Conn) {
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buf := bytes.NewReader(data)
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var cblen uint16
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binary.Read(buf, binary.LittleEndian, &cblen)
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pkt := make([]byte, cblen)
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binary.Read(buf, binary.LittleEndian, &pkt)
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out.Write(pkt)
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}
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