mirror of https://github.com/XTLS/Xray-core
91 lines
1.9 KiB
Go
91 lines
1.9 KiB
Go
package bittorrent
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import (
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"encoding/binary"
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"errors"
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"math"
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"time"
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"github.com/xtls/xray-core/common"
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"github.com/xtls/xray-core/common/buf"
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)
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type SniffHeader struct{}
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func (h *SniffHeader) Protocol() string {
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return "bittorrent"
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}
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func (h *SniffHeader) Domain() string {
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return ""
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}
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var errNotBittorrent = errors.New("not bittorrent header")
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func SniffBittorrent(b []byte) (*SniffHeader, error) {
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if len(b) < 20 {
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return nil, common.ErrNoClue
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}
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if b[0] == 19 && string(b[1:20]) == "BitTorrent protocol" {
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return &SniffHeader{}, nil
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}
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return nil, errNotBittorrent
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}
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func SniffUTP(b []byte) (*SniffHeader, error) {
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if len(b) < 20 {
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return nil, common.ErrNoClue
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}
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buffer := buf.FromBytes(b)
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var typeAndVersion uint8
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if binary.Read(buffer, binary.BigEndian, &typeAndVersion) != nil {
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return nil, common.ErrNoClue
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} else if b[0]>>4&0xF > 4 || b[0]&0xF != 1 {
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return nil, errNotBittorrent
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}
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var extension uint8
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if binary.Read(buffer, binary.BigEndian, &extension) != nil {
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return nil, common.ErrNoClue
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} else if extension != 0 && extension != 1 {
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return nil, errNotBittorrent
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}
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for extension != 0 {
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if extension != 1 {
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return nil, errNotBittorrent
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}
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if binary.Read(buffer, binary.BigEndian, &extension) != nil {
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return nil, common.ErrNoClue
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}
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var length uint8
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if err := binary.Read(buffer, binary.BigEndian, &length); err != nil {
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return nil, common.ErrNoClue
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}
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if common.Error2(buffer.ReadBytes(int32(length))) != nil {
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return nil, common.ErrNoClue
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}
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}
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if common.Error2(buffer.ReadBytes(2)) != nil {
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return nil, common.ErrNoClue
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}
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var timestamp uint32
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if err := binary.Read(buffer, binary.BigEndian, ×tamp); err != nil {
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return nil, common.ErrNoClue
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}
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if math.Abs(float64(time.Now().UnixMicro()-int64(timestamp))) > float64(24*time.Hour) {
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return nil, errNotBittorrent
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}
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return &SniffHeader{}, nil
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}
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