route-test.go

package main

import (
	"fmt"
	"github.com/miekg/bitradix"
	"net"
	"reflect"
)

type ASN uint32

func IPToUint(ip net.IP) (i uint64) {
	ip = ip.To4()
	fv := reflect.ValueOf(&i).Elem()
	fv.SetUint(uint64(uint32(ip[0])<<24 | uint32(ip[1])<<16 | uint32(ip[2])<<8 | uint32(ip[+3])))
	fmt.Printf("%s becomes %d\n", ip.String(), i)
	return
}

func AddRouteString(t *bitradix.Radix, s string, asn ASN) {
	fmt.Println("Adding route for", s)
	_, ipnet, err := net.ParseCIDR(s)
	if err != nil {
		panic("bad network")
	}
	fmt.Printf("ipnet %#v\n", ipnet)
	fmt.Printf("ip %#v\n", ipnet.IP)
	ip := IPToUint(ipnet.IP)
	fmt.Printf("inserting ip %#v\n", ip)
	t.Insert(ip, uint32(asn))
}

func FindRoute(t *bitradix.Radix, ipStr string) int {
	fmt.Println("=== Looking for route for", ipStr)
	_, target, err := net.ParseCIDR(ipStr)
	if err != nil {
		panic("could not parse target")
	}
	iTarget := IPToUint(target.IP)

	node, asn := t.Find(iTarget)
	fmt.Println("Found node", node, "ASN", asn)
	return asn
}

func check(tree *bitradix.Radix, s string, expected_asn int) {
	asn := FindRoute(tree, s)
	fmt.Println("= Got ASN", asn, "expected", expected_asn)
	if asn != expected_asn {
		// panic("wrong asn")
	}
}

func main() {
	tree := bitradix.New()

	AddRouteString(tree, "10.0.0.2/8", 10)
	AddRouteString(tree, "10.20.0.0/14", 20)
	AddRouteString(tree, "10.21.0.0/16", 21)
	AddRouteString(tree, "192.168.0.0/16", 192)
	AddRouteString(tree, "192.168.2.0/24", 1922)

	check(tree, "10.20.1.2/32", 20)
	check(tree, "10.22.1.2/32", 20)
	check(tree, "10.19.0.1/32", 10)
	check(tree, "10.21.0.1/32", 21)
	check(tree, "192.168.2.3/32", 1922)
	check(tree, "230.0.0.1/32", 0)
}