les: fix les/1 CHT compatibility issue (#15692)

les/handler.go

@@ -846,8 +846,8 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
 			}
 
 			if header := pm.blockchain.GetHeaderByNumber(req.BlockNum); header != nil {
-				sectionHead := core.GetCanonicalHash(pm.chainDb, (req.ChtNum+1)*light.ChtV1Frequency-1)
-				if root := light.GetChtRoot(pm.chainDb, req.ChtNum, sectionHead); root != (common.Hash{}) {
+				sectionHead := core.GetCanonicalHash(pm.chainDb, req.ChtNum*light.ChtV1Frequency-1)
+				if root := light.GetChtRoot(pm.chainDb, req.ChtNum-1, sectionHead); root != (common.Hash{}) {
 					if tr, _ := trie.New(root, trieDb); tr != nil {
 						var encNumber [8]byte
 						binary.BigEndian.PutUint64(encNumber[:], req.BlockNum)

les/peer.go

@@ -296,7 +296,7 @@ func (p *peer) RequestHelperTrieProofs(reqID, cost uint64, reqs []HelperTrieReq)
 			}
 			blockNum := binary.BigEndian.Uint64(req.Key)
 			// convert HelperTrie request to old CHT request
-			reqsV1[i] = ChtReq{ChtNum: (req.TrieIdx+1)*(light.ChtFrequency/light.ChtV1Frequency) - 1, BlockNum: blockNum, FromLevel: req.FromLevel}
+			reqsV1[i] = ChtReq{ChtNum: (req.TrieIdx + 1) * (light.ChtFrequency / light.ChtV1Frequency), BlockNum: blockNum, FromLevel: req.FromLevel}
 		}
 		return sendRequest(p.rw, GetHeaderProofsMsg, reqID, cost, reqsV1)
 	case lpv2: