eth/catalyst: add catalyst API prototype (#22641)

This change adds the --catalyst flag, enabling an RPC API for eth2 integration.
In this initial version, catalyst mode also disables all peer-to-peer networking.

Co-authored-by: Mikhail Kalinin <noblesse.knight@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>

cmd/geth/config.go

@@ -28,6 +28,7 @@ import (
 	"gopkg.in/urfave/cli.v1"
 
 	"github.com/ethereum/go-ethereum/cmd/utils"
+	"github.com/ethereum/go-ethereum/eth/catalyst"
 	"github.com/ethereum/go-ethereum/eth/ethconfig"
 	"github.com/ethereum/go-ethereum/internal/ethapi"
 	"github.com/ethereum/go-ethereum/metrics"
@@ -143,7 +144,17 @@ func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend) {
 	if ctx.GlobalIsSet(utils.OverrideBerlinFlag.Name) {
 		cfg.Eth.OverrideBerlin = new(big.Int).SetUint64(ctx.GlobalUint64(utils.OverrideBerlinFlag.Name))
 	}
-	backend := utils.RegisterEthService(stack, &cfg.Eth)
+	backend, eth := utils.RegisterEthService(stack, &cfg.Eth)
+
+	// Configure catalyst.
+	if ctx.GlobalBool(utils.CatalystFlag.Name) {
+		if eth == nil {
+			utils.Fatalf("Catalyst does not work in light client mode.")
+		}
+		if err := catalyst.Register(stack, eth); err != nil {
+			utils.Fatalf("%v", err)
+		}
+	}
 
 	// Configure GraphQL if requested
 	if ctx.GlobalIsSet(utils.GraphQLEnabledFlag.Name) {

cmd/geth/main.go

@@ -151,6 +151,7 @@ var (
 		utils.EVMInterpreterFlag,
 		utils.MinerNotifyFullFlag,
 		configFileFlag,
+		utils.CatalystFlag,
 	}
 
 	rpcFlags = []cli.Flag{

cmd/geth/usage.go

@@ -235,6 +235,7 @@ var AppHelpFlagGroups = []flags.FlagGroup{
 			utils.SnapshotFlag,
 			utils.BloomFilterSizeFlag,
 			cli.HelpFlag,
+			utils.CatalystFlag,
 		},
 	},
 }