mirror of
https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake.git
synced 2025-10-14 05:11:19 -04:00
49 lines
1.3 KiB
Go
49 lines
1.3 KiB
Go
package packetpadding
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import "encoding/binary"
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func New() PacketPaddingContainer {
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return packetPaddingContainer{}
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}
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type packetPaddingContainer struct {
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}
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func (c packetPaddingContainer) Pack(data_OWNERSHIP_RELINQUISHED []byte, paddingLength int) []byte {
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data := append(data_OWNERSHIP_RELINQUISHED, make([]byte, paddingLength)...)
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dataLength := len(data_OWNERSHIP_RELINQUISHED)
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data = binary.BigEndian.AppendUint16(data, uint16(dataLength))
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return data
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}
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func (c packetPaddingContainer) Pad(paddingLength int) []byte {
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if assertPaddingLengthIsNotNegative := paddingLength < 0; assertPaddingLengthIsNotNegative {
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return nil
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}
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switch paddingLength {
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case 0:
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return []byte{}
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case 1:
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return []byte{0}
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case 2:
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return []byte{0, 0}
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default:
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return append(make([]byte, paddingLength-2), byte(paddingLength>>8), byte(paddingLength))
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}
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}
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func (c packetPaddingContainer) Unpack(wrappedData_OWNERSHIP_RELINQUISHED []byte) ([]byte, int) {
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dataLength := len(wrappedData_OWNERSHIP_RELINQUISHED)
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if dataLength < 2 {
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return nil, dataLength
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}
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dataLen := int(binary.BigEndian.Uint16(wrappedData_OWNERSHIP_RELINQUISHED[dataLength-2:]))
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paddingLength := dataLength - dataLen - 2
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if paddingLength < 0 {
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return nil, paddingLength
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}
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return wrappedData_OWNERSHIP_RELINQUISHED[:dataLen], paddingLength
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}
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