mirror of
https://github.com/v2fly/v2ray-core.git
synced 2024-12-23 02:26:49 -05:00
76 lines
1.4 KiB
Go
76 lines
1.4 KiB
Go
package io
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import (
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"errors"
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"hash/fnv"
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"io"
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"github.com/v2ray/v2ray-core/common/alloc"
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"github.com/v2ray/v2ray-core/transport"
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)
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var (
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TruncatedPayload = errors.New("Truncated payload.")
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)
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type ValidationReader struct {
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reader io.Reader
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buffer *alloc.Buffer
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}
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func NewValidationReader(reader io.Reader) *ValidationReader {
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return &ValidationReader{
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reader: reader,
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buffer: alloc.NewLargeBuffer().Clear(),
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}
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}
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func (this *ValidationReader) Read(data []byte) (int, error) {
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nBytes, err := this.reader.Read(data)
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if err != nil {
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return nBytes, err
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}
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nBytesActual := 0
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dataActual := data[:]
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for {
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payload, rest, err := parsePayload(data)
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if err != nil {
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return nBytesActual, err
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}
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copy(dataActual, payload)
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nBytesActual += len(payload)
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dataActual = dataActual[nBytesActual:]
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if len(rest) == 0 {
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break
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}
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data = rest
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}
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return nBytesActual, nil
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}
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func parsePayload(data []byte) (payload []byte, rest []byte, err error) {
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dataLen := len(data)
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if dataLen < 6 {
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err = TruncatedPayload
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return
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}
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payloadLen := int(data[0])<<8 + int(data[1])
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if dataLen < payloadLen+6 {
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err = TruncatedPayload
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return
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}
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payload = data[6 : 6+payloadLen]
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rest = data[6+payloadLen:]
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fnv1a := fnv.New32a()
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fnv1a.Write(payload)
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actualHash := fnv1a.Sum32()
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expectedHash := uint32(data[2])<<24 + uint32(data[3])<<16 + uint32(data[4])<<8 + uint32(data[5])
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if actualHash != expectedHash {
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err = transport.CorruptedPacket
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return
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}
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return
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}
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