46 lines
1.1 KiB
Go
46 lines
1.1 KiB
Go
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// Copyright 2015 The Chihaya Authors. All rights reserved.
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// Use of this source code is governed by the BSD 2-Clause license,
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// which can be found in the LICENSE file.
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package udp
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import (
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"bytes"
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"encoding/binary"
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"net"
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)
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var initialConnectionID = []byte{0x04, 0x17, 0x27, 0x10, 0x19, 0x80}
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func (srv *Server) handlePacket(packet []byte, addr *net.UDPAddr) (response []byte) {
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if len(packet) < 16 {
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return nil // Malformed, no client packets are less than 16 bytes.
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}
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connID := packet[0:8]
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action := binary.BigEndian.Uint32(packet[8:12])
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transactionID := packet[12:16]
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generatedConnID := GenerateConnectionID(addr.IP)
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switch action {
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case 0:
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// Connect request.
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if !bytes.Equal(connID, initialConnectionID) {
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return nil // Malformed packet.
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}
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response = make([]byte, 16)
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writeHeader(response, action, transactionID)
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copy(response[8:], generatedConnID)
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case 1:
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// Announce request.
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}
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return
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}
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func writeHeader(response []byte, action uint32, transactionID []byte) {
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binary.BigEndian.PutUint32(response, action)
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copy(response[4:], transactionID)
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}
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