path: root/p2p/simulations/connect.go

// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package simulations

import (
    "errors"
    "strings"

    "github.com/ethereum/go-ethereum/p2p/enode"
)

var (
    ErrNodeNotFound = errors.New("node not found")
)

// ConnectToLastNode connects the node with provided NodeID
// to the last node that is up, and avoiding connection to self.
// It is useful when constructing a chain network topology
// when Network adds and removes nodes dynamically.
func (net *Network) ConnectToLastNode(id enode.ID) (err error) {
    ids := net.getUpNodeIDs()
    l := len(ids)
    if l < 2 {
        return nil
    }
    last := ids[l-1]
    if last == id {
        last = ids[l-2]
    }
    return net.connect(last, id)
}

// ConnectToRandomNode connects the node with provided NodeID
// to a random node that is up.
func (net *Network) ConnectToRandomNode(id enode.ID) (err error) {
    selected := net.GetRandomUpNode(id)
    if selected == nil {
        return ErrNodeNotFound
    }
    return net.connect(selected.ID(), id)
}

// ConnectNodesFull connects all nodes one to another.
// It provides a complete connectivity in the network
// which should be rarely needed.
func (net *Network) ConnectNodesFull(ids []enode.ID) (err error) {
    if ids == nil {
        ids = net.getUpNodeIDs()
    }
    for i, lid := range ids {
        for _, rid := range ids[i+1:] {
            if err = net.connect(lid, rid); err != nil {
                return err
            }
        }
    }
    return nil
}

// ConnectNodesChain connects all nodes in a chain topology.
// If ids argument is nil, all nodes that are up will be connected.
func (net *Network) ConnectNodesChain(ids []enode.ID) (err error) {
    if ids == nil {
        ids = net.getUpNodeIDs()
    }
    l := len(ids)
    for i := 0; i < l-1; i++ {
        if err := net.connect(ids[i], ids[i+1]); err != nil {
            return err
        }
    }
    return nil
}

// ConnectNodesRing connects all nodes in a ring topology.
// If ids argument is nil, all nodes that are up will be connected.
func (net *Network) ConnectNodesRing(ids []enode.ID) (err error) {
    if ids == nil {
        ids = net.getUpNodeIDs()
    }
    l := len(ids)
    if l < 2 {
        return nil
    }
    if err := net.ConnectNodesChain(ids); err != nil {
        return err
    }
    return net.connect(ids[l-1], ids[0])
}

// ConnectNodesStar connects all nodes into a star topology
// If ids argument is nil, all nodes that are up will be connected.
func (net *Network) ConnectNodesStar(ids []enode.ID, center enode.ID) (err error) {
    if ids == nil {
        ids = net.getUpNodeIDs()
    }
    for _, id := range ids {
        if center == id {
            continue
        }
        if err := net.connect(center, id); err != nil {
            return err
        }
    }
    return nil
}

// connect connects two nodes but ignores already connected error.
func (net *Network) connect(oneID, otherID enode.ID) error {
    return ignoreAlreadyConnectedErr(net.Connect(oneID, otherID))
}

func ignoreAlreadyConnectedErr(err error) error {
    if err == nil || strings.Contains(err.Error(), "already connected") {
        return nil
    }
    return err
}