introduce mapper package

The mapper package contains functions related to creating and marshalling
reponses to machines.

Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>

hscontrol/protocol_common_utils.go

@@ -1,157 +1 @@
 package hscontrol
-
-import (
-	"encoding/binary"
-	"encoding/json"
-	"sync"
-
-	"github.com/juanfont/headscale/hscontrol/types"
-	"github.com/juanfont/headscale/hscontrol/util"
-	"github.com/klauspost/compress/zstd"
-	"github.com/rs/zerolog/log"
-	"tailscale.com/smallzstd"
-	"tailscale.com/tailcfg"
-	"tailscale.com/types/key"
-)
-
-func (h *Headscale) getMapResponseData(
-	mapRequest tailcfg.MapRequest,
-	machine *types.Machine,
-	isNoise bool,
-) ([]byte, error) {
-	mapResponse, err := h.generateMapResponse(mapRequest, machine)
-	if err != nil {
-		return nil, err
-	}
-
-	if isNoise {
-		return h.marshalMapResponse(mapResponse, key.MachinePublic{}, mapRequest.Compress, isNoise)
-	}
-
-	var machineKey key.MachinePublic
-	err = machineKey.UnmarshalText([]byte(util.MachinePublicKeyEnsurePrefix(machine.MachineKey)))
-	if err != nil {
-		log.Error().
-			Caller().
-			Err(err).
-			Msg("Cannot parse client key")
-
-		return nil, err
-	}
-
-	return h.marshalMapResponse(mapResponse, machineKey, mapRequest.Compress, isNoise)
-}
-
-func (h *Headscale) getMapKeepAliveResponseData(
-	mapRequest tailcfg.MapRequest,
-	machine *types.Machine,
-	isNoise bool,
-) ([]byte, error) {
-	keepAliveResponse := tailcfg.MapResponse{
-		KeepAlive: true,
-	}
-
-	if isNoise {
-		return h.marshalMapResponse(
-			keepAliveResponse,
-			key.MachinePublic{},
-			mapRequest.Compress,
-			isNoise,
-		)
-	}
-
-	var machineKey key.MachinePublic
-	err := machineKey.UnmarshalText([]byte(util.MachinePublicKeyEnsurePrefix(machine.MachineKey)))
-	if err != nil {
-		log.Error().
-			Caller().
-			Err(err).
-			Msg("Cannot parse client key")
-
-		return nil, err
-	}
-
-	return h.marshalMapResponse(keepAliveResponse, machineKey, mapRequest.Compress, isNoise)
-}
-
-func (h *Headscale) marshalResponse(
-	resp interface{},
-	machineKey key.MachinePublic,
-	isNoise bool,
-) ([]byte, error) {
-	jsonBody, err := json.Marshal(resp)
-	if err != nil {
-		log.Error().
-			Caller().
-			Err(err).
-			Msg("Cannot marshal response")
-
-		return nil, err
-	}
-
-	if isNoise {
-		return jsonBody, nil
-	}
-
-	return h.privateKey.SealTo(machineKey, jsonBody), nil
-}
-
-func (h *Headscale) marshalMapResponse(
-	resp interface{},
-	machineKey key.MachinePublic,
-	compression string,
-	isNoise bool,
-) ([]byte, error) {
-	jsonBody, err := json.Marshal(resp)
-	if err != nil {
-		log.Error().
-			Caller().
-			Err(err).
-			Msg("Cannot marshal map response")
-	}
-
-	var respBody []byte
-	if compression == util.ZstdCompression {
-		respBody = zstdEncode(jsonBody)
-		if !isNoise { // if legacy protocol
-			respBody = h.privateKey.SealTo(machineKey, respBody)
-		}
-	} else {
-		if !isNoise { // if legacy protocol
-			respBody = h.privateKey.SealTo(machineKey, jsonBody)
-		} else {
-			respBody = jsonBody
-		}
-	}
-
-	data := make([]byte, reservedResponseHeaderSize)
-	binary.LittleEndian.PutUint32(data, uint32(len(respBody)))
-	data = append(data, respBody...)
-
-	return data, nil
-}
-
-func zstdEncode(in []byte) []byte {
-	encoder, ok := zstdEncoderPool.Get().(*zstd.Encoder)
-	if !ok {
-		panic("invalid type in sync pool")
-	}
-	out := encoder.EncodeAll(in, nil)
-	_ = encoder.Close()
-	zstdEncoderPool.Put(encoder)
-
-	return out
-}
-
-var zstdEncoderPool = &sync.Pool{
-	New: func() any {
-		encoder, err := smallzstd.NewEncoder(
-			nil,
-			zstd.WithEncoderLevel(zstd.SpeedFastest))
-		if err != nil {
-			panic(err)
-		}
-
-		return encoder
-	},
-}