les: implement ultralight client (#16904)

For more information about this light client mode, read
https://hackmd.io/s/HJy7jjZpm

les/fetcher_test.go

@@ -0,0 +1,155 @@
+package les
+
+import (
+	"math/big"
+	"testing"
+
+	"net"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/p2p/enode"
+)
+
+func TestFetcherULCPeerSelector(t *testing.T) {
+
+	var (
+		id1 enode.ID = newNodeID(t).ID()
+		id2 enode.ID = newNodeID(t).ID()
+		id3 enode.ID = newNodeID(t).ID()
+		id4 enode.ID = newNodeID(t).ID()
+	)
+
+	ftn1 := &fetcherTreeNode{
+		hash: common.HexToHash("1"),
+		td:   big.NewInt(1),
+	}
+	ftn2 := &fetcherTreeNode{
+		hash:   common.HexToHash("2"),
+		td:     big.NewInt(2),
+		parent: ftn1,
+	}
+	ftn3 := &fetcherTreeNode{
+		hash:   common.HexToHash("3"),
+		td:     big.NewInt(3),
+		parent: ftn2,
+	}
+	lf := lightFetcher{
+		pm: &ProtocolManager{
+			ulc: &ulc{
+				trustedKeys: map[string]struct{}{
+					id1.String(): {},
+					id2.String(): {},
+					id3.String(): {},
+					id4.String(): {},
+				},
+				minTrustedFraction: 70,
+			},
+		},
+		maxConfirmedTd: ftn1.td,
+
+		peers: map[*peer]*fetcherPeerInfo{
+			{
+				id:        "peer1",
+				Peer:      p2p.NewPeer(id1, "peer1", []p2p.Cap{}),
+				isTrusted: true,
+			}: {
+				nodeByHash: map[common.Hash]*fetcherTreeNode{
+					ftn1.hash: ftn1,
+					ftn2.hash: ftn2,
+				},
+			},
+			{
+				Peer:      p2p.NewPeer(id2, "peer2", []p2p.Cap{}),
+				id:        "peer2",
+				isTrusted: true,
+			}: {
+				nodeByHash: map[common.Hash]*fetcherTreeNode{
+					ftn1.hash: ftn1,
+					ftn2.hash: ftn2,
+				},
+			},
+			{
+				id:        "peer3",
+				Peer:      p2p.NewPeer(id3, "peer3", []p2p.Cap{}),
+				isTrusted: true,
+			}: {
+				nodeByHash: map[common.Hash]*fetcherTreeNode{
+					ftn1.hash: ftn1,
+					ftn2.hash: ftn2,
+					ftn3.hash: ftn3,
+				},
+			},
+			{
+				id:        "peer4",
+				Peer:      p2p.NewPeer(id4, "peer4", []p2p.Cap{}),
+				isTrusted: true,
+			}: {
+				nodeByHash: map[common.Hash]*fetcherTreeNode{
+					ftn1.hash: ftn1,
+				},
+			},
+		},
+		chain: &lightChainStub{
+			tds: map[common.Hash]*big.Int{},
+			headers: map[common.Hash]*types.Header{
+				ftn1.hash: {},
+				ftn2.hash: {},
+				ftn3.hash: {},
+			},
+		},
+	}
+	bestHash, bestAmount, bestTD, sync := lf.findBestRequest()
+
+	if bestTD == nil {
+		t.Fatal("Empty result")
+	}
+
+	if bestTD.Cmp(ftn2.td) != 0 {
+		t.Fatal("bad td", bestTD)
+	}
+	if bestHash != ftn2.hash {
+		t.Fatal("bad hash", bestTD)
+	}
+
+	_, _ = bestAmount, sync
+}
+
+type lightChainStub struct {
+	BlockChain
+	tds                         map[common.Hash]*big.Int
+	headers                     map[common.Hash]*types.Header
+	insertHeaderChainAssertFunc func(chain []*types.Header, checkFreq int) (int, error)
+}
+
+func (l *lightChainStub) GetHeader(hash common.Hash, number uint64) *types.Header {
+	if h, ok := l.headers[hash]; ok {
+		return h
+	}
+
+	return nil
+}
+
+func (l *lightChainStub) LockChain()   {}
+func (l *lightChainStub) UnlockChain() {}
+
+func (l *lightChainStub) GetTd(hash common.Hash, number uint64) *big.Int {
+	if td, ok := l.tds[hash]; ok {
+		return td
+	}
+	return nil
+}
+
+func (l *lightChainStub) InsertHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
+	return l.insertHeaderChainAssertFunc(chain, checkFreq)
+}
+
+func newNodeID(t *testing.T) *enode.Node {
+	key, err := crypto.GenerateKey()
+	if err != nil {
+		t.Fatal("generate key err:", err)
+	}
+	return enode.NewV4(&key.PublicKey, net.IP{}, 35000, 35000)
+}