1 files changed, 176 insertions, 0 deletions
diff --git a/p2p/simulations/connect.go b/p2p/simulations/connect.go
new file mode 100644
index 000000000..606dda056
--- /dev/null
+++ b/p2p/simulations/connect.go
@@ -0,0 +1,176 @@
+// 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")
+	ErrNoPivotNode  = errors.New("no pivot node set")
+)
+
+// ConnectToPivotNode connects the node with provided NodeID
+// to the pivot node, already set by Network.SetPivotNode method.
+// It is useful when constructing a star network topology
+// when Network adds and removes nodes dynamically.
+func (net *Network) ConnectToPivotNode(id enode.ID) (err error) {
+	pivot := net.GetPivotNode()
+	if pivot == nil {
+		return ErrNoPivotNode
+	}
+	return net.connect(pivot.ID(), id)
+}
+
+// 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 in a star topology
+// with the center at provided NodeID.
+// If ids argument is nil, all nodes that are up will be connected.
+func (net *Network) ConnectNodesStar(pivot enode.ID, ids []enode.ID) (err error) {
+	if ids == nil {
+		ids = net.getUpNodeIDs()
+	}
+	for _, id := range ids {
+		if pivot == id {
+			continue
+		}
+		if err := net.connect(pivot, id); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// ConnectNodesStarPivot connects all nodes in a star topology
+// with the center at already set pivot node.
+// If ids argument is nil, all nodes that are up will be connected.
+func (net *Network) ConnectNodesStarPivot(ids []enode.ID) (err error) {
+	pivot := net.GetPivotNode()
+	if pivot == nil {
+		return ErrNoPivotNode
+	}
+	return net.ConnectNodesStar(pivot.ID(), ids)
+}
+
+// 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
+}
+
+// SetPivotNode sets the NodeID of the network's pivot node.
+// Pivot node is just a specific node that should be treated
+// differently then other nodes in test. SetPivotNode and
+// GetPivotNode are just a convenient functions to set and
+// retrieve it.
+func (net *Network) SetPivotNode(id enode.ID) {
+	net.lock.Lock()
+	defer net.lock.Unlock()
+	net.pivotNodeID = id
+}
+
+// GetPivotNode returns NodeID of the pivot node set by
+// Network.SetPivotNode method.
+func (net *Network) GetPivotNode() (node *Node) {
+	net.lock.RLock()
+	defer net.lock.RUnlock()
+	return net.getNode(net.pivotNodeID)
+}