122 lines
3.9 KiB
Go
122 lines
3.9 KiB
Go
package main
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import (
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"fmt"
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"net"
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"strings"
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)
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func getASNRepresentation(asn string) string {
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records, err := net.LookupTXT(fmt.Sprintf("AS%s.%s", asn, setting.dnsInterface))
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if err != nil {
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// DNS query failed, only use ASN as output
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return fmt.Sprintf("AS%s", asn)
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}
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result := strings.Join(records, " ")
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if resultSplit := strings.Split(result, " | "); len(resultSplit) > 1 {
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result = strings.Join(resultSplit[1:], "\\n")
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}
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return fmt.Sprintf("AS%s\\n%s", asn, result)
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}
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func birdRouteToGraphviz(servers []string, responses []string, target string) string {
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graph := make(map[string]string)
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// Helper to add an edge
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addEdge := func(src string, dest string, attr string) {
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key := "\"" + src + "\" -> \"" + dest + "\""
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_, present := graph[key]
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// Do not remove edge's attributes if it's already present
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if present && len(attr) == 0 {
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return
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}
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graph[key] = attr
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}
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// Helper to set attribute for a point in graph
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addPoint := func(name string, attr string) {
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key := "\"" + name + "\""
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_, present := graph[key]
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// Do not remove point's attributes if it's already present
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if present && len(attr) == 0 {
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return
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}
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graph[key] = attr
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}
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addPoint("Target: "+target, "[color=red,shape=diamond]")
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for serverID, server := range servers {
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response := responses[serverID]
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if len(response) == 0 {
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continue
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}
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addPoint(server, "[color=blue,shape=box]")
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// This is the best split point I can find for bird2
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routes := strings.Split(response, "\tvia ")
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routeFound := false
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for routeIndex, route := range routes {
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var routeNexthop string
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var routeASPath string
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var routePreferred bool = routeIndex > 0 && strings.Contains(routes[routeIndex-1], "*")
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// Have to look at previous slice to determine if route is preferred, due to bad split point selection
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for _, routeParameter := range strings.Split(route, "\n") {
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if strings.HasPrefix(routeParameter, "\tBGP.next_hop: ") {
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routeNexthop = strings.TrimPrefix(routeParameter, "\tBGP.next_hop: ")
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} else if strings.HasPrefix(routeParameter, "\tBGP.as_path: ") {
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routeASPath = strings.TrimPrefix(routeParameter, "\tBGP.as_path: ")
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}
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}
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if len(routeASPath) == 0 {
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// Either this is not a BGP route, or the information is incomplete
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continue
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}
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// Connect each node on AS path
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paths := strings.Split(strings.TrimSpace(routeASPath), " ")
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for pathIndex := range paths {
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paths[pathIndex] = strings.TrimPrefix(paths[pathIndex], "(")
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paths[pathIndex] = strings.TrimSuffix(paths[pathIndex], ")")
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}
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// First step starting from originating server
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if len(paths) > 0 {
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if len(routeNexthop) > 0 {
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// Edge from originating server to nexthop
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addEdge(server, "Nexthop:\\n"+routeNexthop, (map[bool]string{true: "[color=red]"})[routePreferred])
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// and from nexthop to AS
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addEdge("Nexthop:\\n"+routeNexthop, getASNRepresentation(paths[0]), (map[bool]string{true: "[color=red]"})[routePreferred])
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addPoint("Nexthop:\\n"+routeNexthop, "[shape=diamond]")
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routeFound = true
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} else {
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// Edge from originating server to AS
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addEdge(server, getASNRepresentation(paths[0]), (map[bool]string{true: "[color=red]"})[routePreferred])
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routeFound = true
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}
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}
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// Following steps, edges between AS
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for pathIndex := range paths {
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if pathIndex == 0 {
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continue
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}
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addEdge(getASNRepresentation(paths[pathIndex-1]), getASNRepresentation(paths[pathIndex]), (map[bool]string{true: "[color=red]"})[routePreferred])
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}
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// Last AS to destination
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addEdge(getASNRepresentation(paths[len(paths)-1]), "Target: "+target, (map[bool]string{true: "[color=red]"})[routePreferred])
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}
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if !routeFound {
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// Cannot find a path starting from this server
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addEdge(server, "Target: "+target, "[color=gray,label=\"?\"]")
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}
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}
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// Combine all graphviz commands
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var result string
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for edge, attr := range graph {
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result += edge + " " + attr + ";\n"
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}
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return "digraph {\n" + result + "}\n"
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}
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