cmd, contracts, les: discard stale checkpoint

cmd/registrar/query.go

@@ -19,7 +19,6 @@ package main
 import (
 	"errors"
 	"fmt"
-	"math/big"
 
 	"github.com/ethereum/go-ethereum/cmd/utils"
 	"github.com/ethereum/go-ethereum/common"
@@ -46,7 +45,6 @@ var commandQueryCheckpoint = cli.Command{
 Fetch the registered checkpoint with the specified index.
 `,
 	Flags: []cli.Flag{
-		checkpointIndexFlag,
 		clientURLFlag,
 	},
 	Action: utils.MigrateFlags(queryCheckpoint),
@@ -84,20 +82,11 @@ func queryAdmin(ctx *cli.Context) error {
 // registrar contract.
 func queryCheckpoint(ctx *cli.Context) error {
 	contract := setupContract(setupDialContext(ctx))
-	if ctx.GlobalIsSet(checkpointIndexFlag.Name) {
+	index, checkpoint, height, err := contract.Contract().GetLatestCheckpoint(nil)
-		index := ctx.GlobalInt64(checkpointIndexFlag.Name)
+	if err != nil {
-		checkpoint, height, err := contract.Contract().GetCheckpoint(nil, big.NewInt(index))
+		return err
-		if err != nil {
-			return err
-		}
-		fmt.Printf("Checkpoint(registered at height #%d) %d => %s\n", height, index, common.Hash(checkpoint).Hex())
-	} else {
-		index, checkpoint, height, err := contract.Contract().GetLatestCheckpoint(nil)
-		if err != nil {
-			return err
-		}
-		fmt.Printf("Latest checkpoint(registered at height #%d) %d => %s\n", height, index, common.Hash(checkpoint).Hex())
 	}
+	fmt.Printf("Latest checkpoint(registered at height #%d) %d => %s\n", height, index, common.Hash(checkpoint).Hex())
 	return nil
 }
 

contracts/registrar/contract/registrar.sol

@@ -68,22 +68,7 @@ contract Registrar {
     view
     public
     returns(uint, bytes32, uint) {
-        (bytes32 hash, uint height) = GetCheckpoint(latest);
+        return (sectionIndex, hash, height);
-        return (latest, hash, height);
-    }
-
-    /**
-     * @dev Get a stable checkpoint information with specified section index.
-     * @param _sectionIndex section index
-     * @return checkpoint hash
-     * @return the associated register block height
-     */
-    function GetCheckpoint(uint _sectionIndex)
-    view
-    public
-    returns(bytes32, uint)
-    {
-        return (checkpoints[_sectionIndex], register_height[_sectionIndex]);
     }
 
     /**
@@ -115,7 +100,7 @@ contract Registrar {
             return false;
         }
         // Filter out stale announcement
-        if (_sectionIndex == latest && (latest != 0 || register_height[0] != 0)) {
+        if (_sectionIndex == sectionIndex && (sectionIndex != 0 || height != 0)) {
             return false;
         }
         // Filter out invalid announcement
@@ -134,7 +119,15 @@ contract Registrar {
         bool isNew = (old == "");
         pending_proposal.usermap[msg.sender] = _hash;
 
-        if (!isNew) {
+        if (isNew) {
+            // New checkpoint announcement
+            pending_proposal.count += 1;
+            pending_proposal.index = _sectionIndex;
+            pending_proposal.votemap[_hash].push(Vote({
+                addr: msg.sender,
+                sig:  _sig
+            }));
+        } else {
             // Checkpoint modification
             Vote[] storage votes = pending_proposal.votemap[old];
             for (uint i = 0; i < votes.length - 1; i++) {
@@ -149,21 +142,14 @@ contract Registrar {
                 addr: msg.sender,
                 sig:  _sig
             }));
-        } else {
-            // New checkpoint announcement
-            pending_proposal.count += 1;
-            pending_proposal.index = _sectionIndex;
-            pending_proposal.votemap[_hash].push(Vote({
-                addr: msg.sender,
-                sig:  _sig
-            }));
         }
         if (pending_proposal.votemap[_hash].length < threshold) {
            return true;
         }
-        checkpoints[_sectionIndex] = _hash;
+        // Update latest checkpoint
-        register_height[_sectionIndex] = block.number;
+        hash = _hash;
-        latest = _sectionIndex;
+        height = block.number;
+        sectionIndex = _sectionIndex;
 
         bytes memory sigs;
         for (uint idx = 0; idx < threshold; idx++) {
@@ -243,15 +229,15 @@ contract Registrar {
     // A list of admin users so that we can obtain all admin users.
     address[] adminList;
 
-    // Registered checkpoint information
-    mapping(uint => bytes32) checkpoints;
-
     // Latest stored section id
     // Note all registered checkpoint information should continuous with previous one.
-    uint latest;
+    uint sectionIndex;
 
     // The block height associated with latest registered checkpoint.
-    mapping(uint => uint) register_height;
+    uint height;
+
+    // The hash of latest registered checkpoint.
+    bytes32 hash;
 
     // The frequency for creating a checkpoint
     //

les/registrar.go

@@ -18,7 +18,6 @@
 package les
 
 import (
-	"math/big"
 	"sync/atomic"
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
@@ -87,21 +86,22 @@ func (reg *checkpointRegistrar) isRunning() bool {
 // stableCheckpoint returns the stable checkpoint which generated by local indexers
 // and announced by trusted signers.
 func (reg *checkpointRegistrar) stableCheckpoint() (*params.TrustedCheckpoint, uint64) {
-	latest, hash, _, err := reg.contract.Contract().GetLatestCheckpoint(nil)
+	latest, hash, height, err := reg.contract.Contract().GetLatestCheckpoint(nil)
+	// Short circuit if the checkpoint contract is empty.
 	if err != nil || latest.Uint64() == 0 && hash == [32]byte{} {
 		return nil, 0
 	}
-	index := latest.Uint64()
+	local := reg.getLocal(latest.Uint64())
-	for {
+	// The following scenarios may occur:
-		local := reg.getLocal(index)
+	//
-		hash, height, err := reg.contract.Contract().GetCheckpoint(nil, big.NewInt(int64(index)))
+	// * local node is out of sync so that it doesn't have the
-		if err == nil && local.HashEqual(common.Hash(hash)) {
+	//   checkpoint which registered in the contract.
-			return &local, height.Uint64()
+	// * local checkpoint doesn't match with the registered one.
-		}
+	//
-		if index == 0 {
+	// In both cases, server won't send the **stable** checkpoint
-			break
+	// to the client(no worry, client can use hardcoded one instead).
-		}
+	if local.HashEqual(common.Hash(hash)) {
-		index -= 1
+		return &local, height.Uint64()
 	}
 	return nil, 0
 }