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https://github.com/v2fly/v2ray-core.git
synced 2024-09-14 07:58:16 -04:00
72 lines
1.9 KiB
Go
72 lines
1.9 KiB
Go
package wire
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import (
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"bytes"
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"io"
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"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/protocol"
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"v2ray.com/core/external/github.com/lucas-clemente/quic-go/internal/utils"
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)
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// A CryptoFrame is a CRYPTO frame
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type CryptoFrame struct {
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Offset protocol.ByteCount
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Data []byte
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}
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func parseCryptoFrame(r *bytes.Reader, _ protocol.VersionNumber) (*CryptoFrame, error) {
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if _, err := r.ReadByte(); err != nil {
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return nil, err
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}
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frame := &CryptoFrame{}
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offset, err := utils.ReadVarInt(r)
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if err != nil {
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return nil, err
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}
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frame.Offset = protocol.ByteCount(offset)
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dataLen, err := utils.ReadVarInt(r)
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if err != nil {
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return nil, err
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}
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if dataLen > uint64(r.Len()) {
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return nil, io.EOF
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}
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if dataLen != 0 {
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frame.Data = make([]byte, dataLen)
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if _, err := io.ReadFull(r, frame.Data); err != nil {
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// this should never happen, since we already checked the dataLen earlier
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return nil, err
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}
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}
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return frame, nil
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}
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func (f *CryptoFrame) Write(b *bytes.Buffer, _ protocol.VersionNumber) error {
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b.WriteByte(0x6)
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utils.WriteVarInt(b, uint64(f.Offset))
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utils.WriteVarInt(b, uint64(len(f.Data)))
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b.Write(f.Data)
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return nil
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}
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// Length of a written frame
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func (f *CryptoFrame) Length(_ protocol.VersionNumber) protocol.ByteCount {
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return 1 + utils.VarIntLen(uint64(f.Offset)) + utils.VarIntLen(uint64(len(f.Data))) + protocol.ByteCount(len(f.Data))
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}
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// MaxDataLen returns the maximum data length
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func (f *CryptoFrame) MaxDataLen(maxSize protocol.ByteCount) protocol.ByteCount {
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// pretend that the data size will be 1 bytes
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// if it turns out that varint encoding the length will consume 2 bytes, we need to adjust the data length afterwards
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headerLen := 1 + utils.VarIntLen(uint64(f.Offset)) + 1
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if headerLen > maxSize {
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return 0
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}
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maxDataLen := maxSize - headerLen
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if utils.VarIntLen(uint64(maxDataLen)) != 1 {
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maxDataLen--
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}
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return maxDataLen
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}
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