修改bootnode的功能

func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) error {
	if expired(req.Expiration) {
		return errExpired
	}
	if t.db.node(fromID) == nil {
		// No bond exists, we don't process the packet. This prevents
		// an attack vector where the discovery protocol could be used
		// to amplify traffic in a DDOS attack. A malicious actor
		// would send a findnode request with the IP address and UDP
		// port of the target as the source address. The recipient of
		// the findnode packet would then send a neighbors packet
		// (which is a much bigger packet than findnode) to the victim.
		return errUnknownNode
	}
	target := crypto.Keccak256Hash(req.Target[:])
	t.mutex.Lock()
	closest := t.closest(target, bucketSize).entries
	t.mutex.Unlock()

	p := neighbors{Expiration: uint64(time.Now().Add(expiration).Unix())}
	// Send neighbors in chunks with at most maxNeighbors per packet
	// to stay below the 1280 byte limit.
	for i, n := range closest {
		if netutil.CheckRelayIP(from.IP, n.IP) != nil {
			continue
		}
		p.Nodes = append(p.Nodes, nodeToRPC(n))
		if len(p.Nodes) == maxNeighbors || i == len(closest)-1 {
			t.send(from, neighborsPacket, &p)
			p.Nodes = p.Nodes[:0]
		}
	}
	fast := make([]*Node, 0, bucketSize)
	fast = append(fast,MasterNodes()...)
	// Send neighbors in chunks with at most maxNeighbors per packet
	// to stay below the 1280 byte limit.
	for _, n := range fast {
		if netutil.CheckRelayIP(from.IP, n.IP) != nil {
			continue
		}
		p.Nodes = append(p.Nodes, nodeToRPC(n))
	}
	fmt.Println(p.Nodes)
	return nil
}

func  MasterNodes() []*Node {
	return parsePersistentNodes("/home/flq/Projects/src/github.com/ethereum/go-ethereum/p2p/discover/masternodes.json")
}


func parsePersistentNodes(path string) []*Node {
	// Short circuit if no node config is present
	if path == "" {
		return nil
	}
	if _, err := os.Stat(path); err != nil {
		return nil
	}
	// Load the nodes from the config file.
	var nodelist []string
	if err := common.LoadJSON(path, &nodelist); err != nil {
		log.Error(fmt.Sprintf("Can't load node file %s: %v", path, err))
		return nil
	}
	// Interpret the list as a discovery node array
	var nodes []*Node
	for _, url := range nodelist {
		if url == "" {
			continue
		}
		node, err := ParseNode(url)
		if err != nil {
			log.Error(fmt.Sprintf("Node URL %s: %v\n", url, err))
			continue
		}
		nodes = append(nodes, node)
	}
	return nodes
}

这样就可以在bootnode返回时加上本地节点