126 lines
2.7 KiB
Go
126 lines
2.7 KiB
Go
package tendrils
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import "fmt"
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type Link struct {
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NodeA *Node
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InterfaceA string
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NodeB *Node
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InterfaceB string
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}
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func (l *Link) String() string {
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nameA := l.NodeA.DisplayName()
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if nameA == "" {
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nameA = l.NodeA.FirstMAC()
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}
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nameB := l.NodeB.DisplayName()
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if nameB == "" {
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nameB = l.NodeB.FirstMAC()
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}
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sideA := nameA
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if l.InterfaceA != "" {
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sideA = nameA + ":" + l.InterfaceA
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}
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sideB := nameB
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if l.InterfaceB != "" {
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sideB = nameB + ":" + l.InterfaceB
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}
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return fmt.Sprintf("%s <-> %s", sideA, sideB)
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}
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func (n *Nodes) getDirectLinks() []*Link {
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macToNode := map[string]*Node{}
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for _, node := range n.nodes {
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for _, iface := range node.Interfaces {
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if iface.MAC != nil {
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macToNode[iface.MAC.String()] = node
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}
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}
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}
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seen := map[string]bool{}
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var links []*Link
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for _, target := range n.nodes {
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seenMACs := map[string]bool{}
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for _, iface := range target.Interfaces {
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if iface.MAC == nil {
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continue
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}
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mac := iface.MAC.String()
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if seenMACs[mac] {
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continue
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}
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seenMACs[mac] = true
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lastHop, lastPort := n.findLastHop(target, mac, macToNode)
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if lastHop == nil {
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continue
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}
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targetIface := n.findTargetInterface(target, lastHop, macToNode)
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key := makeLinkKey(lastHop, lastPort, target, targetIface)
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if !seen[key] {
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seen[key] = true
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links = append(links, &Link{
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NodeA: lastHop,
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InterfaceA: lastPort,
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NodeB: target,
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InterfaceB: targetIface,
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})
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}
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}
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}
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return links
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}
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func (n *Nodes) findLastHop(target *Node, mac string, macToNode map[string]*Node) (*Node, string) {
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for _, node := range n.nodes {
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port, sees := node.MACTable[mac]
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if !sees || node == target {
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continue
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}
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if !n.hasCloserNode(node, target, mac, port, macToNode) {
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return node, port
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}
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}
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return nil, ""
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}
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func (n *Nodes) hasCloserNode(node, target *Node, mac, port string, macToNode map[string]*Node) bool {
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for otherMAC, otherPort := range node.MACTable {
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if otherPort != port {
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continue
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}
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otherNode := macToNode[otherMAC]
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if otherNode == nil || otherNode == node || otherNode == target {
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continue
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}
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if _, alsoSees := otherNode.MACTable[mac]; alsoSees {
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return true
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}
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}
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return false
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}
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func (n *Nodes) findTargetInterface(target, lastHop *Node, macToNode map[string]*Node) string {
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for lastHopMAC, targetPort := range target.MACTable {
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if macToNode[lastHopMAC] == lastHop {
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return targetPort
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}
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}
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return ""
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}
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func makeLinkKey(nodeA *Node, ifaceA string, nodeB *Node, ifaceB string) string {
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ptrA := fmt.Sprintf("%p", nodeA)
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ptrB := fmt.Sprintf("%p", nodeB)
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if ptrA < ptrB {
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return ptrA + ":" + ifaceA + "-" + ptrB + ":" + ifaceB
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}
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return ptrB + ":" + ifaceB + "-" + ptrA + ":" + ifaceA
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}
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