From 4b1a7abb42a1cc85e4862906b7b694b89e6cc12d Mon Sep 17 00:00:00 2001
From: Milos Gajdos <milosgajdos83@gmail.com>
Date: Thu, 5 Sep 2019 00:16:22 +0100
Subject: [PATCH] Freeze network graph when building full network topology

Also added some comments and debug logs
---
 network/default.go         | 77 ++++++++++++++++++++++----------------
 network/handler/handler.go |  1 +
 2 files changed, 46 insertions(+), 32 deletions(-)

diff --git a/network/default.go b/network/default.go
index 4a6d4bb4..94ee1d25 100644
--- a/network/default.go
+++ b/network/default.go
@@ -300,7 +300,7 @@ func (n *network) processNetChan(l tunnel.Listener) {
 					continue
 				}
 				n.Lock()
-				log.Debugf("Network connect message received from: %s", pbNetConnect.Node.Id)
+				log.Debugf("Network received connect message from: %s", pbNetConnect.Node.Id)
 				// if the entry already exists skip adding it
 				if neighbour, ok := n.neighbours[pbNetConnect.Node.Id]; ok {
 					// update lastSeen timestamp
@@ -332,8 +332,8 @@ func (n *network) processNetChan(l tunnel.Listener) {
 					continue
 				}
 				n.Lock()
-				log.Debugf("Network neighbour message received from: %s", pbNetNeighbour.Node.Id)
-				// only add the neighbour if it's not already in the neighbourhood
+				log.Debugf("Network received neighbour message from: %s", pbNetNeighbour.Node.Id)
+				// only add the neighbour if it is NOT already in node's list of neighbours
 				if _, ok := n.neighbours[pbNetNeighbour.Node.Id]; !ok {
 					n.neighbours[pbNetNeighbour.Node.Id] = &node{
 						id:         pbNetNeighbour.Node.Id,
@@ -347,10 +347,14 @@ func (n *network) processNetChan(l tunnel.Listener) {
 					n.neighbours[pbNetNeighbour.Node.Id].lastSeen = now
 				}
 				// update/store the neighbour node neighbours
+				// NOTE: * we dont update lastSeen time for the neighbours of the neighbour
+				//	 * even though we are NOT interested in neighbours of neighbours here
+				// 	   we still allocate the map of neighbours for each of them
 				for _, pbNeighbour := range pbNetNeighbour.Neighbours {
 					neighbourNode := &node{
-						id:      pbNeighbour.Id,
-						address: pbNeighbour.Address,
+						id:         pbNeighbour.Id,
+						address:    pbNeighbour.Address,
+						neighbours: make(map[string]*node),
 					}
 					n.neighbours[pbNetNeighbour.Node.Id].neighbours[neighbourNode.id] = neighbourNode
 				}
@@ -366,6 +370,7 @@ func (n *network) processNetChan(l tunnel.Listener) {
 					continue
 				}
 				n.Lock()
+				log.Debugf("Network received close message from: %s", pbNetClose.Node.Id)
 				if err := n.pruneNode(pbNetClose.Node.Id); err != nil {
 					log.Debugf("Network failed to prune the node %s: %v", pbNetClose.Node.Id, err)
 					continue
@@ -423,6 +428,7 @@ func (n *network) announce(client transport.Client) {
 				Body: body,
 			}
 
+			log.Debugf("Network sending neighbour message from: %s", node.Id)
 			if err := client.Send(&m); err != nil {
 				log.Debugf("Network failed to send neighbour messsage: %v", err)
 				continue
@@ -704,6 +710,7 @@ func (n *network) advertise(client transport.Client, advertChan <-chan *router.A
 				Body: body,
 			}
 
+			log.Debugf("Network sending advert message from: %s", pbRtrAdvert.Id)
 			if err := client.Send(&m); err != nil {
 				log.Debugf("Network failed to send advert %s: %v", pbRtrAdvert.Id, err)
 				continue
@@ -839,6 +846,12 @@ func (n *network) Nodes() []Node {
 	visited := make(map[string]*node)
 	// queue of the nodes to visit
 	queue := list.New()
+
+	// we need to freeze the network graph here
+	// otherwise we might get invalid results
+	n.RLock()
+	defer n.RUnlock()
+
 	// push network node to the back of queue
 	queue.PushBack(n.node)
 	// mark the node as visited
@@ -898,39 +911,39 @@ func (n *network) Close() error {
 	case <-n.closed:
 		return nil
 	default:
+		// send close message only if we managed to connect to NetworkChannel
+		if netClient, ok := n.tunClient[NetworkChannel]; ok {
+			// send connect message to NetworkChannel
+			node := &pbNet.Node{
+				Id:      n.options.Id,
+				Address: n.options.Address,
+			}
+			pbNetClose := &pbNet.Close{
+				Node: node,
+			}
+
+			// only proceed with sending to NetworkChannel if marshal succeeds
+			if body, err := proto.Marshal(pbNetClose); err == nil {
+				// create transport message and chuck it down the pipe
+				m := transport.Message{
+					Header: map[string]string{
+						"Micro-Method": "close",
+					},
+					Body: body,
+				}
+
+				log.Debugf("Network sending close message from: %s", node.Id)
+				if err := netClient.Send(&m); err != nil {
+					log.Debugf("Network failed to send close messsage: %v", err)
+				}
+			}
+		}
 		// TODO: send close message to the network channel
 		close(n.closed)
 		// set connected to false
 		n.connected = false
 	}
 
-	// send close message only if we managed to connect to NetworkChannel
-	if netClient, ok := n.tunClient[NetworkChannel]; ok {
-		// send connect message to NetworkChannel
-		node := &pbNet.Node{
-			Id:      n.options.Id,
-			Address: n.options.Address,
-		}
-		pbNetClose := &pbNet.Close{
-			Node: node,
-		}
-
-		// only proceed with sending to NetworkChannel if marshal succeeds
-		if body, err := proto.Marshal(pbNetClose); err == nil {
-			// create transport message and chuck it down the pipe
-			m := transport.Message{
-				Header: map[string]string{
-					"Micro-Method": "close",
-				},
-				Body: body,
-			}
-
-			if err := netClient.Send(&m); err != nil {
-				log.Debugf("Network failed to send close messsage: %v", err)
-			}
-		}
-	}
-
 	return n.close()
 }
 
diff --git a/network/handler/handler.go b/network/handler/handler.go
index 3740d4a9..1d8d74a8 100644
--- a/network/handler/handler.go
+++ b/network/handler/handler.go
@@ -1,3 +1,4 @@
+// Package handler implements network RPC handler
 package handler
 
 import (