TUN-4597: Add a QUIC server skeleton

- Added a QUIC server to accept streams
- Unit test for this server also tests ALPN
- Temporary echo capability for HTTP ConnectionType

vendor/github.com/lucas-clemente/quic-go/internal/wire/version_negotiation.go

@@ -0,0 +1,54 @@
+package wire
+
+import (
+	"bytes"
+	"crypto/rand"
+	"errors"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/utils"
+)
+
+// ParseVersionNegotiationPacket parses a Version Negotiation packet.
+func ParseVersionNegotiationPacket(b *bytes.Reader) (*Header, []protocol.VersionNumber, error) {
+	hdr, err := parseHeader(b, 0)
+	if err != nil {
+		return nil, nil, err
+	}
+	if b.Len() == 0 {
+		//nolint:stylecheck
+		return nil, nil, errors.New("Version Negotiation packet has empty version list")
+	}
+	if b.Len()%4 != 0 {
+		//nolint:stylecheck
+		return nil, nil, errors.New("Version Negotiation packet has a version list with an invalid length")
+	}
+	versions := make([]protocol.VersionNumber, b.Len()/4)
+	for i := 0; b.Len() > 0; i++ {
+		v, err := utils.BigEndian.ReadUint32(b)
+		if err != nil {
+			return nil, nil, err
+		}
+		versions[i] = protocol.VersionNumber(v)
+	}
+	return hdr, versions, nil
+}
+
+// ComposeVersionNegotiation composes a Version Negotiation
+func ComposeVersionNegotiation(destConnID, srcConnID protocol.ConnectionID, versions []protocol.VersionNumber) ([]byte, error) {
+	greasedVersions := protocol.GetGreasedVersions(versions)
+	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
+	buf := bytes.NewBuffer(make([]byte, 0, expectedLen))
+	r := make([]byte, 1)
+	_, _ = rand.Read(r) // ignore the error here. It is not critical to have perfect random here.
+	buf.WriteByte(r[0] | 0x80)
+	utils.BigEndian.WriteUint32(buf, 0) // version 0
+	buf.WriteByte(uint8(destConnID.Len()))
+	buf.Write(destConnID)
+	buf.WriteByte(uint8(srcConnID.Len()))
+	buf.Write(srcConnID)
+	for _, v := range greasedVersions {
+		utils.BigEndian.WriteUint32(buf, uint32(v))
+	}
+	return buf.Bytes(), nil
+}