forked from quic-go/quic-go
73 lines
1.4 KiB
Go
73 lines
1.4 KiB
Go
package quic
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import "io"
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// The PublicHeader of a QUIC packet
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type PublicHeader struct {
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VersionFlag bool
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ResetFlag bool
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ConnectionIDLength uint8
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ConnectionID uint64
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QuicVersion uint32
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PacketNumberLength uint8
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PacketNumber uint64
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}
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// ParsePublicHeader parses a QUIC packet's public header
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func ParsePublicHeader(b io.ByteReader) (*PublicHeader, error) {
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header := &PublicHeader{}
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// First byte
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publicFlagByte, err := b.ReadByte()
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if err != nil {
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return nil, err
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}
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header.VersionFlag = publicFlagByte&0x01 > 0
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header.ResetFlag = publicFlagByte&0x02 > 0
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switch publicFlagByte & 0x0C {
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case 0x0C:
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header.ConnectionIDLength = 8
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case 0x08:
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header.ConnectionIDLength = 4
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case 0x04:
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header.ConnectionIDLength = 1
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}
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switch publicFlagByte & 0x30 {
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case 0x30:
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header.PacketNumberLength = 6
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case 0x20:
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header.PacketNumberLength = 4
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case 0x10:
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header.PacketNumberLength = 2
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case 0x00:
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header.PacketNumberLength = 1
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}
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// Connection ID
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header.ConnectionID, err = readUintN(b, header.ConnectionIDLength)
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if err != nil {
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return nil, err
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}
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// Version (optional)
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if header.VersionFlag {
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var v uint64
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v, err = readUintN(b, 4)
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if err != nil {
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return nil, err
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}
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header.QuicVersion = uint32(v)
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}
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// Packet number
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header.PacketNumber, err = readUintN(b, header.PacketNumberLength)
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if err != nil {
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return nil, err
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}
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return header, nil
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}
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