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frontend: BGPmap improvements (#36)

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* bgpmap: Compact nexthop info into an edge label

* bgpmap: parse and show non-BGP routes

* bgpmap: Misc tweaks

- Show the protocol name instead of the ASN in edge labels
- Correctly draw only the primary path if there are multiple routes to the first neighbour ASN in a path
- Use a smaller font size for edge labels

* bgpmap_test: update to match new changes

* bgpmap: Split route info on all (non-empty) rta_dest_names values
This commit is contained in:
James Lu 2021-08-31 07:44:14 -07:00 committed by GitHub
parent fbd190628c
commit 1a3c618522
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 56 additions and 27 deletions
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77
frontend/bgpmap.go
View File

@ -4,6 +4,7 @@ import (
"fmt"
"html"
"net"
"regexp"
"strings"
)
@ -48,8 +49,8 @@ func birdRouteToGraphviz(servers []string, responses []string, target string) st
addEdge := func(src string, dest string, attr string) {
key := "\"" + html.EscapeString(src) + "\" -> \"" + html.EscapeString(dest) + "\""
_, present := graph[key]
// Do not remove edge's attributes if it's already present
if present && len(attr) == 0 {
// If there are multiple edges / routes between 2 nodes, only pick the first one
if present {
return
}
graph[key] = attr
@ -64,6 +65,12 @@ func birdRouteToGraphviz(servers []string, responses []string, target string) st
}
graph[key] = attr
}
// The protocol name for each route (e.g. "ibgp_sea02") is encoded in the form:
// unicast [ibgp_sea02 2021-08-27 from fd86:bad:11b7:1::1] * (100/1015) [i]
protocolNameRe := regexp.MustCompile(`\[(.*?) .*\]`)
// Try to split the output into one chunk for each route.
// Possible values are defined at https://gitlab.nic.cz/labs/bird/-/blob/v2.0.8/nest/rt-attr.c#L81-87
routeSplitRe := regexp.MustCompile("(unicast|blackhole|unreachable|prohibited)")
addPoint("Target: "+target, "[color=red,shape=diamond]")
for serverID, server := range servers {
@ -72,24 +79,44 @@ func birdRouteToGraphviz(servers []string, responses []string, target string) st
continue
}
addPoint(server, "[color=blue,shape=box]")
// This is the best split point I can find for bird2
routes := strings.Split(response, "\tvia ")
routeFound := false
routes := routeSplitRe.Split(response, -1)
targetNodeName := "Target: " + target
var nonBGPRoutes []string
var nonBGPRoutePreferred bool
for routeIndex, route := range routes {
var routeNexthop string
var routeASPath string
var routePreferred bool = routeIndex > 0 && strings.Contains(routes[routeIndex-1], "*")
// Have to look at previous slice to determine if route is preferred, due to bad split point selection
var routePreferred bool = routeIndex > 0 && strings.Contains(route, "*")
// Track non-BGP routes in the output by their protocol name, but draw them altogether in one line
// so that there are no conflicts in the edge label
var protocolName string
for _, routeParameter := range strings.Split(route, "\n") {
if strings.HasPrefix(routeParameter, "\tBGP.next_hop: ") {
routeNexthop = strings.TrimPrefix(routeParameter, "\tBGP.next_hop: ")
} else if strings.HasPrefix(routeParameter, "\tBGP.as_path: ") {
routeASPath = strings.TrimPrefix(routeParameter, "\tBGP.as_path: ")
} else {
match := protocolNameRe.FindStringSubmatch(routeParameter)
if len(match) >= 2 {
protocolName = match[1]
}
}
}
if routePreferred {
protocolName = protocolName + "*"
}
if len(routeASPath) == 0 {
// Either this is not a BGP route, or the information is incomplete
if routeIndex == 0 {
// The first string split includes the target prefix and isn't a valid route
continue
}
if routePreferred {
nonBGPRoutePreferred = true
}
nonBGPRoutes = append(nonBGPRoutes, protocolName)
continue
}
@ -103,18 +130,15 @@ func birdRouteToGraphviz(servers []string, responses []string, target string) st
// First step starting from originating server
if len(paths) > 0 {
if len(routeNexthop) > 0 {
// Edge from originating server to nexthop
addEdge(server, "Nexthop:\\n"+routeNexthop, (map[bool]string{true: "[color=red]"})[routePreferred])
// and from nexthop to AS
addEdge("Nexthop:\\n"+routeNexthop, getASNRepresentation(paths[0]), (map[bool]string{true: "[color=red]"})[routePreferred])
addPoint("Nexthop:\\n"+routeNexthop, "[shape=diamond]")
routeFound = true
} else {
// Edge from originating server to AS
addEdge(server, getASNRepresentation(paths[0]), (map[bool]string{true: "[color=red]"})[routePreferred])
routeFound = true
attrs := []string{"fontsize=12.0"}
if routePreferred {
attrs = append(attrs, "color=red")
}
if len(routeNexthop) > 0 {
attrs = append(attrs, fmt.Sprintf("label=\"%s\\n%s\"", protocolName, routeNexthop))
}
formattedAttr := fmt.Sprintf("[%s]", strings.Join(attrs, ","))
addEdge(server, getASNRepresentation(paths[0]), formattedAttr)
}
// Following steps, edges between AS
@ -125,12 +149,19 @@ func birdRouteToGraphviz(servers []string, responses []string, target string) st
addEdge(getASNRepresentation(paths[pathIndex-1]), getASNRepresentation(paths[pathIndex]), (map[bool]string{true: "[color=red]"})[routePreferred])
}
// Last AS to destination
addEdge(getASNRepresentation(paths[len(paths)-1]), "Target: "+target, (map[bool]string{true: "[color=red]"})[routePreferred])
addEdge(getASNRepresentation(paths[len(paths)-1]), targetNodeName, (map[bool]string{true: "[color=red]"})[routePreferred])
}
if !routeFound {
// Cannot find a path starting from this server
addEdge(server, "Target: "+target, "[color=gray,label=\"?\"]")
if len(nonBGPRoutes) > 0 {
protocolsForRoute := fmt.Sprintf("label=\"%s\"", strings.Join(nonBGPRoutes, "\\n"))
attrs := []string{protocolsForRoute, "fontsize=12.0"}
if nonBGPRoutePreferred {
attrs = append(attrs, "color=red")
}
formattedAttr := fmt.Sprintf("[%s]", strings.Join(attrs, ","))
addEdge(server, targetNodeName, formattedAttr)
}
}

6
frontend/bgpmap_test.go
View File

@ -45,12 +45,10 @@ func TestBirdRouteToGraphviz(t *testing.T) {
BGP.next_hop: 172.18.0.2`
expectedResult := `digraph {
"Nexthop:\n172.18.0.2" -> "AS4242422601" [color=red];
"Nexthop:\n172.18.0.2" [shape=diamond];
"AS4242422601" -> "Target: 192.168.0.1" [color=red];
"Target: 192.168.0.1" [color=red,shape=diamond];
"alpha" [color=blue,shape=box];
"alpha" -> "Nexthop:\n172.18.0.2" [color=red];
"alpha" -> "AS4242422601" [fontsize=12.0,color=red,label="alpha*\n172.18.0.2"];
"AS4242422601" -> "Target: 192.168.0.1" [color=red];
}`
result := birdRouteToGraphviz([]string{