Revert "fast network membership check"

This reverts commit 98f036359b.

render/container_test.go

@@ -2,6 +2,7 @@ package render_test
 
 import (
 	"fmt"
+	"net"
 	"testing"
 
 	"github.com/weaveworks/common/test"
@@ -45,10 +46,11 @@ type testcase struct {
 }
 
 func testMap(t *testing.T, f render.MapFunc, input testcase) {
-	localNetworks := report.NewNetworks()
-	if err := localNetworks.AddCIDR("1.2.3.0/16"); err != nil {
+	_, ipNet, err := net.ParseCIDR("1.2.3.0/16")
+	if err != nil {
 		t.Fatalf(err.Error())
 	}
+	localNetworks := report.Networks([]*net.IPNet{ipNet})
 	if have := f(input.n, localNetworks); input.ok != (len(have) > 0) {
 		name := input.name
 		if name == "" {

render/theinternet.go

@@ -1,6 +1,7 @@
 package render
 
 import (
+	"net"
 	"regexp"
 	"strings"
 
@@ -67,15 +68,26 @@ func isKnownService(hostname string) bool {
 // used to determine which nodes in the report are "remote", i.e. outside of
 // our infrastructure.
 func LocalNetworks(r report.Report) report.Networks {
-	networks := report.NewNetworks()
+	var (
+		result   = report.Networks{}
+		networks = map[string]struct{}{}
+	)
 
 	for _, topology := range []report.Topology{r.Host, r.Overlay} {
 		for _, md := range topology.Nodes {
 			nets, _ := md.Sets.Lookup(host.LocalNetworks)
 			for _, s := range nets {
-				networks.AddCIDR(s)
+				_, ipNet, err := net.ParseCIDR(s)
+				if err != nil {
+					continue
+				}
+				_, ok := networks[ipNet.String()]
+				if !ok {
+					result = append(result, ipNet)
+					networks[ipNet.String()] = struct{}{}
+				}
 			}
 		}
 	}
-	return networks
+	return result
 }

render/theinternet_test.go

@@ -1,6 +1,7 @@
 package render_test
 
 import (
+	"net"
 	"reflect"
 	"testing"
 
@@ -29,14 +30,21 @@ func TestReportLocalNetworks(t *testing.T) {
 			},
 		},
 	})
-	want := report.NewNetworks()
-	for _, cidr := range []string{"10.0.0.1/8", "192.168.1.1/24", "10.32.0.1/12"} {
-		if err := want.AddCIDR(cidr); err != nil {
-			panic(err)
-		}
-	}
+	want := report.Networks([]*net.IPNet{
+		mustParseCIDR("10.0.0.1/8"),
+		mustParseCIDR("192.168.1.1/24"),
+		mustParseCIDR("10.32.0.1/12"),
+	})
 	have := render.LocalNetworks(r)
 	if !reflect.DeepEqual(want, have) {
 		t.Errorf("%s", test.Diff(want, have))
 	}
 }
+
+func mustParseCIDR(s string) *net.IPNet {
+	_, ipNet, err := net.ParseCIDR(s)
+	if err != nil {
+		panic(err)
+	}
+	return ipNet
+}