65 lines
1.4 KiB
Go
65 lines
1.4 KiB
Go
package transport
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import "encoding/binary"
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const kcpPacketHeaderSize = 24
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func parseKCPPacketMetadata(packet []byte) (*uint32, []KCPPacketDebugSegment) {
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conv := parseKCPConversationID(packet)
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segments, ok := parseKCPPacketSegments(packet)
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if !ok {
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return conv, nil
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}
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return conv, segments
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}
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func parseKCPConversationID(packet []byte) *uint32 {
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if len(packet) < 4 {
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return nil
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}
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conv := binary.LittleEndian.Uint32(packet[:4])
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return &conv
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}
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// ParseKCPConversationID 从原始 KCP UDP datagram 中提取 conv ID。
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func ParseKCPConversationID(packet []byte) (uint32, bool) {
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conv := parseKCPConversationID(packet)
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if conv == nil {
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return 0, false
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}
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return *conv, true
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}
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func parseKCPPacketSegments(packet []byte) ([]KCPPacketDebugSegment, bool) {
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if len(packet) == 0 {
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return nil, false
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}
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data := packet
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segments := make([]KCPPacketDebugSegment, 0, 1)
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for len(data) > 0 {
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if len(data) < kcpPacketHeaderSize {
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return nil, false
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}
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segmentLen := binary.LittleEndian.Uint32(data[20:])
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totalLen := kcpPacketHeaderSize + int(segmentLen)
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if len(data) < totalLen {
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return nil, false
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}
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segments = append(segments, KCPPacketDebugSegment{
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Cmd: data[4],
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Frg: data[5],
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Wnd: binary.LittleEndian.Uint16(data[6:8]),
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SN: binary.LittleEndian.Uint32(data[12:16]),
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UNA: binary.LittleEndian.Uint32(data[16:20]),
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Len: segmentLen,
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})
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data = data[totalLen:]
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}
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return segments, true
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}
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