mirror of
https://github.com/refraction-networking/uquic.git
synced 2025-04-04 20:57:36 +03:00
95575f5fe7
uTLS is not yet bumped to the new version, so this commit breaks the dependencies relationship by getting rid of the local replace.
53 lines
1.9 KiB
Go
53 lines
1.9 KiB
Go
package wire
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import (
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"bytes"
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"crypto/rand"
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"encoding/binary"
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"errors"
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"github.com/refraction-networking/uquic/internal/protocol"
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"github.com/refraction-networking/uquic/internal/utils"
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)
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// ParseVersionNegotiationPacket parses a Version Negotiation packet.
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func ParseVersionNegotiationPacket(b []byte) (dest, src protocol.ArbitraryLenConnectionID, _ []protocol.VersionNumber, _ error) {
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n, dest, src, err := ParseArbitraryLenConnectionIDs(b)
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if err != nil {
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return nil, nil, nil, err
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}
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b = b[n:]
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if len(b) == 0 {
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//nolint:stylecheck
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return nil, nil, nil, errors.New("Version Negotiation packet has empty version list")
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}
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if len(b)%4 != 0 {
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//nolint:stylecheck
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return nil, nil, nil, errors.New("Version Negotiation packet has a version list with an invalid length")
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}
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versions := make([]protocol.VersionNumber, len(b)/4)
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for i := 0; len(b) > 0; i++ {
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versions[i] = protocol.VersionNumber(binary.BigEndian.Uint32(b[:4]))
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b = b[4:]
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}
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return dest, src, versions, nil
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}
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// ComposeVersionNegotiation composes a Version Negotiation
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func ComposeVersionNegotiation(destConnID, srcConnID protocol.ArbitraryLenConnectionID, versions []protocol.VersionNumber) []byte {
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greasedVersions := protocol.GetGreasedVersions(versions)
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expectedLen := 1 /* type byte */ + 4 /* version field */ + 1 /* dest connection ID length field */ + destConnID.Len() + 1 /* src connection ID length field */ + srcConnID.Len() + len(greasedVersions)*4
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buf := bytes.NewBuffer(make([]byte, 0, expectedLen))
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r := make([]byte, 1)
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_, _ = rand.Read(r) // ignore the error here. It is not critical to have perfect random here.
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buf.WriteByte(r[0] | 0x80)
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utils.BigEndian.WriteUint32(buf, 0) // version 0
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buf.WriteByte(uint8(destConnID.Len()))
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buf.Write(destConnID.Bytes())
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buf.WriteByte(uint8(srcConnID.Len()))
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buf.Write(srcConnID.Bytes())
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for _, v := range greasedVersions {
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utils.BigEndian.WriteUint32(buf, uint32(v))
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}
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return buf.Bytes()
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}
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