tailscale/net/interfaces/interfaces_test.go
Josh Bleecher Snyder ad5e04249b wgengine/monitor: ignore adding/removing uninteresting IPs
One of the most common "unexpected" log lines is:

"network state changed, but stringification didn't"

One way that this can occur is if an interesting interface
(non-Tailscale, has interesting IP address)
gains or loses an uninteresting IP address (link local or loopback).

The fact that the interface is interesting is enough for EqualFiltered
to inspect it. The fact that an IP address changed is enough for
EqualFiltered to declare that the interfaces are not equal.

But the State.String method reasonably declines to print any
uninteresting IP addresses. As a result, the network state appears
to have changed, but the stringification did not.

The String method is correct; nothing interesting happened.

This change fixes this by adding an IP address filter to EqualFiltered
in addition to the interface filter. This lets the network monitor
ignore the addition/removal of uninteresting IP addresses.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-11-22 16:33:15 -08:00

107 lines
2.9 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package interfaces
import (
"encoding/json"
"net"
"testing"
"inet.af/netaddr"
)
func TestGetState(t *testing.T) {
st, err := GetState()
if err != nil {
t.Fatal(err)
}
j, err := json.MarshalIndent(st, "", "\t")
if err != nil {
t.Errorf("JSON: %v", err)
}
t.Logf("Got: %s", j)
t.Logf("As string: %s", st)
st2, err := GetState()
if err != nil {
t.Fatal(err)
}
if !st.EqualFiltered(st2, UseAllInterfaces, UseAllIPs) {
// let's assume nobody was changing the system network interfaces between
// the two GetState calls.
t.Fatal("two States back-to-back were not equal")
}
t.Logf("As string:\n\t%s", st)
}
func TestLikelyHomeRouterIP(t *testing.T) {
gw, my, ok := LikelyHomeRouterIP()
if !ok {
t.Logf("no result")
return
}
t.Logf("myIP = %v; gw = %v", my, gw)
}
func TestIsUsableV6(t *testing.T) {
tests := []struct {
name string
ip string
want bool
}{
{"first ULA", "fc00::1", true},
{"Tailscale", "fd7a:115c:a1e0::1", false},
{"Cloud Run", "fddf:3978:feb1:d745::1", true},
{"zeros", "0000:0000:0000:0000:0000:0000:0000:0000", false},
{"Link Local", "fe80::1", false},
{"Global", "2602::1", true},
{"IPv4 public", "192.0.2.1", false},
{"IPv4 private", "192.168.1.1", false},
}
for _, test := range tests {
if got := isUsableV6(netaddr.MustParseIP(test.ip)); got != test.want {
t.Errorf("isUsableV6(%s) = %v, want %v", test.name, got, test.want)
}
}
}
func TestStateEqualFilteredIPFilter(t *testing.T) {
// s1 and s2 are identical, except that an "interesting" interface
// has gained an "uninteresting" IP address.
s1 := &State{
InterfaceIPs: map[string][]netaddr.IPPrefix{"x": {
netaddr.MustParseIPPrefix("42.0.0.0/8"),
netaddr.MustParseIPPrefix("169.254.0.0/16"), // link local unicast
}},
Interface: map[string]Interface{"x": {Interface: &net.Interface{Name: "x"}}},
}
s2 := &State{
InterfaceIPs: map[string][]netaddr.IPPrefix{"x": {
netaddr.MustParseIPPrefix("42.0.0.0/8"),
netaddr.MustParseIPPrefix("169.254.0.0/16"), // link local unicast
netaddr.MustParseIPPrefix("127.0.0.0/8"), // loopback (added)
}},
Interface: map[string]Interface{"x": {Interface: &net.Interface{Name: "x"}}},
}
// s1 and s2 are different...
if s1.EqualFiltered(s2, UseAllInterfaces, UseAllIPs) {
t.Errorf("%+v != %+v", s1, s2)
}
// ...and they look different if you only restrict to interesting interfaces...
if s1.EqualFiltered(s2, UseInterestingInterfaces, UseAllIPs) {
t.Errorf("%+v != %+v when restricting to interesting interfaces _but not_ IPs", s1, s2)
}
// ...but because the additional IP address is uninteresting, we should treat them as the same.
if !s1.EqualFiltered(s2, UseInterestingInterfaces, UseInterestingIPs) {
t.Errorf("%+v == %+v when restricting to interesting interfaces and IPs", s1, s2)
}
}