Revert "les: remove obsolete code related to PoW header syncing (ethe…

…reum#27737)"

This reverts commit d84ccdb.

cmd/geth/main.go

@@ -93,6 +93,9 @@ var (
 		utils.LightMaxPeersFlag,
 		utils.LightNoPruneFlag,
 		utils.LightKDFFlag,
+		utils.UltraLightServersFlag,
+		utils.UltraLightFractionFlag,
+		utils.UltraLightOnlyAnnounceFlag,
 		utils.LightNoSyncServeFlag,
 		utils.EthRequiredBlocksFlag,
 		utils.LegacyWhitelistFlag,

cmd/utils/flags.go

@@ -61,6 +61,7 @@ import (
 	"github.com/ethereum/go-ethereum/internal/ethapi"
 	"github.com/ethereum/go-ethereum/internal/flags"
 	"github.com/ethereum/go-ethereum/les"
+	lescatalyst "github.com/ethereum/go-ethereum/les/catalyst"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/metrics/exp"
@@ -293,6 +294,23 @@ var (
 		Value:    ethconfig.Defaults.LightPeers,
 		Category: flags.LightCategory,
 	}
+	UltraLightServersFlag = &cli.StringFlag{
+		Name:     "ulc.servers",
+		Usage:    "List of trusted ultra-light servers",
+		Value:    strings.Join(ethconfig.Defaults.UltraLightServers, ","),
+		Category: flags.LightCategory,
+	}
+	UltraLightFractionFlag = &cli.IntFlag{
+		Name:     "ulc.fraction",
+		Usage:    "Minimum % of trusted ultra-light servers required to announce a new head",
+		Value:    ethconfig.Defaults.UltraLightFraction,
+		Category: flags.LightCategory,
+	}
+	UltraLightOnlyAnnounceFlag = &cli.BoolFlag{
+		Name:     "ulc.onlyannounce",
+		Usage:    "Ultra light server sends announcements only",
+		Category: flags.LightCategory,
+	}
 	LightNoPruneFlag = &cli.BoolFlag{
 		Name:     "light.nopruning",
 		Usage:    "Disable ancient light chain data pruning",
@@ -1193,6 +1211,19 @@ func setLes(ctx *cli.Context, cfg *ethconfig.Config) {
 	if ctx.IsSet(LightMaxPeersFlag.Name) {
 		cfg.LightPeers = ctx.Int(LightMaxPeersFlag.Name)
 	}
+	if ctx.IsSet(UltraLightServersFlag.Name) {
+		cfg.UltraLightServers = strings.Split(ctx.String(UltraLightServersFlag.Name), ",")
+	}
+	if ctx.IsSet(UltraLightFractionFlag.Name) {
+		cfg.UltraLightFraction = ctx.Int(UltraLightFractionFlag.Name)
+	}
+	if cfg.UltraLightFraction <= 0 && cfg.UltraLightFraction > 100 {
+		log.Error("Ultra light fraction is invalid", "had", cfg.UltraLightFraction, "updated", ethconfig.Defaults.UltraLightFraction)
+		cfg.UltraLightFraction = ethconfig.Defaults.UltraLightFraction
+	}
+	if ctx.IsSet(UltraLightOnlyAnnounceFlag.Name) {
+		cfg.UltraLightOnlyAnnounce = ctx.Bool(UltraLightOnlyAnnounceFlag.Name)
+	}
 	if ctx.IsSet(LightNoPruneFlag.Name) {
 		cfg.LightNoPrune = ctx.Bool(LightNoPruneFlag.Name)
 	}
@@ -1853,6 +1884,9 @@ func RegisterEthService(stack *node.Node, cfg *ethconfig.Config) (ethapi.Backend
 			Fatalf("Failed to register the Ethereum service: %v", err)
 		}
 		stack.RegisterAPIs(tracers.APIs(backend.ApiBackend))
+		if err := lescatalyst.Register(stack, backend); err != nil {
+			Fatalf("Failed to register the Engine API service: %v", err)
+		}
 		return backend.ApiBackend, nil
 	}
 	backend, err := eth.New(stack, cfg)

eth/ethconfig/config.go

@@ -61,6 +61,7 @@ var Defaults = Config{
 	NetworkId:          1,
 	TxLookupLimit:      2350000,
 	LightPeers:         100,
+	UltraLightFraction: 75,
 	DatabaseCache:      512,
 	TrieCleanCache:     154,
 	TrieDirtyCache:     256,
@@ -110,6 +111,11 @@ type Config struct {
 	LightNoPrune     bool `toml:",omitempty"` // Whether to disable light chain pruning
 	LightNoSyncServe bool `toml:",omitempty"` // Whether to serve light clients before syncing
 
+	// Ultra Light client options
+	UltraLightServers      []string `toml:",omitempty"` // List of trusted ultra light servers
+	UltraLightFraction     int      `toml:",omitempty"` // Percentage of trusted servers to accept an announcement
+	UltraLightOnlyAnnounce bool     `toml:",omitempty"` // Whether to only announce headers, or also serve them
+
 	// Database options
 	SkipBcVersionCheck bool `toml:"-"`
 	DatabaseHandles    int  `toml:"-"`

les/api_backend.go

@@ -57,6 +57,7 @@ func (b *LesApiBackend) CurrentBlock() *types.Header {
 }
 
 func (b *LesApiBackend) SetHead(number uint64) {
+	b.eth.handler.downloader.Cancel()
 	b.eth.blockchain.SetHead(number)
 }
 
@@ -263,7 +264,7 @@ func (b *LesApiBackend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEven
 }
 
 func (b *LesApiBackend) SyncProgress() ethereum.SyncProgress {
-	return ethereum.SyncProgress{}
+	return b.eth.Downloader().Progress()
 }
 
 func (b *LesApiBackend) ProtocolVersion() int {

les/api_test.go

@@ -31,8 +31,9 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/eth"
-	"github.com/ethereum/go-ethereum/eth/downloader"
+	ethdownloader "github.com/ethereum/go-ethereum/eth/downloader"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
+	"github.com/ethereum/go-ethereum/les/downloader"
 	"github.com/ethereum/go-ethereum/les/flowcontrol"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/node"
@@ -492,13 +493,13 @@ func testSim(t *testing.T, serverCount, clientCount int, serverDir, clientDir []
 
 func newLesClientService(ctx *adapters.ServiceContext, stack *node.Node) (node.Lifecycle, error) {
 	config := ethconfig.Defaults
-	config.SyncMode = downloader.LightSync
+	config.SyncMode = (ethdownloader.SyncMode)(downloader.LightSync)
 	return New(stack, &config)
 }
 
 func newLesServerService(ctx *adapters.ServiceContext, stack *node.Node) (node.Lifecycle, error) {
 	config := ethconfig.Defaults
-	config.SyncMode = downloader.FullSync
+	config.SyncMode = (ethdownloader.SyncMode)(downloader.FullSync)
 	config.LightServ = testServerCapacity
 	config.LightPeers = testMaxClients
 	ethereum, err := eth.New(stack, &config)