Merge pull request #141 from squat/fix_graph

pkg/mesh: fix panic in graph

pkg/mesh/graph.go

@@ -27,7 +27,7 @@ import (
 func (t *Topology) Dot() (string, error) {
 	g := gographviz.NewGraph()
 	g.Name = "kilo"
-	if err := g.AddAttr("kilo", string(gographviz.Label), graphEscape(t.wireGuardCIDR.String())); err != nil {
+	if err := g.AddAttr("kilo", string(gographviz.Label), graphEscape((&net.IPNet{IP: t.wireGuardCIDR.IP.Mask(t.wireGuardCIDR.Mask), Mask: t.wireGuardCIDR.Mask}).String())); err != nil {
 		return "", fmt.Errorf("failed to add label to graph")
 	}
 	if err := g.AddAttr("kilo", string(gographviz.LabelLOC), "t"); err != nil {

pkg/mesh/mesh.go

@@ -477,7 +477,11 @@ func (m *Mesh) applyTopology() {
 		return
 	}
 	// Update the node's WireGuard IP.
-	m.wireGuardIP = t.wireGuardCIDR
+	if t.leader {
+		m.wireGuardIP = t.wireGuardCIDR
+	} else {
+		m.wireGuardIP = nil
+	}
 	conf := t.Conf()
 	buf, err := conf.Bytes()
 	if err != nil {

pkg/mesh/topology.go

@@ -50,8 +50,10 @@ type Topology struct {
 	// subnet is the Pod subnet of the local node.
 	subnet *net.IPNet
 	// wireGuardCIDR is the allocated CIDR of the WireGuard
-	// interface of the local node. If the local node is not
-	// the leader, then it is nil.
+	// interface of the local node within the Kilo subnet.
+	// If the local node is not the leader of a location, then
+	// the IP is the 0th address in the subnet, i.e. the CIDR
+	// is equal to the Kilo subnet.
 	wireGuardCIDR *net.IPNet
 }
 
@@ -104,7 +106,7 @@ func NewTopology(nodes map[string]*Node, peers map[string]*Peer, granularity Gra
 		localLocation = nodeLocationPrefix + hostname
 	}
 
-	t := Topology{key: key, port: port, hostname: hostname, location: localLocation, persistentKeepalive: persistentKeepalive, privateIP: nodes[hostname].InternalIP, subnet: nodes[hostname].Subnet}
+	t := Topology{key: key, port: port, hostname: hostname, location: localLocation, persistentKeepalive: persistentKeepalive, privateIP: nodes[hostname].InternalIP, subnet: nodes[hostname].Subnet, wireGuardCIDR: subnet}
 	for location := range topoMap {
 		// Sort the location so the result is stable.
 		sort.Slice(topoMap[location], func(i, j int) bool {

pkg/mesh/topology_test.go

@@ -215,7 +215,7 @@ func TestNewTopology(t *testing.T) {
 				location:      logicalLocationPrefix + nodes["b"].Location,
 				subnet:        nodes["c"].Subnet,
 				privateIP:     nodes["c"].InternalIP,
-				wireGuardCIDR: nil,
+				wireGuardCIDR: DefaultKiloSubnet,
 				segments: []*segment{
 					{
 						allowedIPs:  []*net.IPNet{nodes["a"].Subnet, nodes["a"].InternalIP, {IP: w1, Mask: net.CIDRMask(32, 32)}},