60 lines
1.9 KiB
Go
60 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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"github.com/lucas-clemente/quic-go/internal/protocol"
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"github.com/lucas-clemente/quic-go/internal/utils"
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)
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// ComposeGQUICVersionNegotiation composes a Version Negotiation Packet for gQUIC
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func ComposeGQUICVersionNegotiation(connID protocol.ConnectionID, versions []protocol.VersionNumber) []byte {
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fullReply := &bytes.Buffer{}
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ph := Header{
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ConnectionID: connID,
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PacketNumber: 1,
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VersionFlag: true,
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IsVersionNegotiation: true,
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}
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if err := ph.writePublicHeader(fullReply, protocol.PerspectiveServer, protocol.VersionWhatever); err != nil {
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utils.Errorf("error composing version negotiation packet: %s", err.Error())
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return nil
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}
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writeVersions(fullReply, versions)
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return fullReply.Bytes()
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}
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// ComposeVersionNegotiation composes a Version Negotiation according to the IETF draft
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func ComposeVersionNegotiation(
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connID protocol.ConnectionID,
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pn protocol.PacketNumber,
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versions []protocol.VersionNumber,
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) []byte {
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fullReply := &bytes.Buffer{}
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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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h := Header{
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IsLongHeader: true,
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Type: protocol.PacketType(r[0] | 0x80),
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ConnectionID: connID,
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PacketNumber: pn,
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Version: 0,
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IsVersionNegotiation: true,
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}
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if err := h.writeHeader(fullReply); err != nil {
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utils.Errorf("error composing version negotiation packet: %s", err.Error())
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return nil
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}
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writeVersions(fullReply, versions)
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return fullReply.Bytes()
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}
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// writeVersions writes the versions for a Version Negotiation Packet.
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// It inserts one reserved version number at a random position.
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func writeVersions(buf *bytes.Buffer, supported []protocol.VersionNumber) {
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for _, v := range protocol.GetGreasedVersions(supported) {
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utils.BigEndian.WriteUint32(buf, uint32(v))
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}
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}
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