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net/{interfaces,netmon}: remove "interesting", EqualFiltered API

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This removes a lot of API from net/interfaces (including all the
filter types, EqualFiltered, active Tailscale interface func, etc) and
moves the "major" change detection to net/netmon which knows more
about the world and the previous/new states.

Updates #9040

Change-Id: I7fe66a23039c6347ae5458745b709e7ebdcce245
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
2023-08-23 11:48:05 -07:00
committed by Brad Fitzpatrick
parent 6dfa403e6b
commit 11ece02f52
7 changed files with 476 additions and 196 deletions
Download Patch File Download Diff File Expand all files Collapse all files
net/netmon/netmon.go
+97 -3
View File
@@ -55,6 +55,10 @@ type Monitor struct {
change chan bool // send false to wake poller, true to also force ChangeDeltas be sent
stop chan struct{} // closed on Stop
// Things that must be set early, before use,
// and not change at runtime.
tsIfName string // tailscale interface name, if known/set ("tailscale0", "utun3", ...)
mu sync.Mutex // guards all following fields
cbs set.HandleSet[ChangeFunc]
ruleDelCB set.HandleSet[RuleDeleteCallback]
@@ -76,6 +80,9 @@ type ChangeFunc func(*ChangeDelta)
// ChangeDelta describes the difference between two network states.
type ChangeDelta struct {
// Monitor is the network monitor that sent this delta.
Monitor *Monitor
// Old is the old interface state, if known.
// It's nil if the old state is unknown.
// Do not mutate it.
@@ -145,6 +152,15 @@ func (m *Monitor) interfaceStateUncached() (*interfaces.State, error) {
return interfaces.GetState()
}
// SetTailscaleInterfaceName sets the name of the Tailscale interface. For
// example, "tailscale0", "tun0", "utun3", etc.
//
// This must be called only early in tailscaled startup before the monitor is
// used.
func (m *Monitor) SetTailscaleInterfaceName(ifName string) {
m.tsIfName = ifName
}
// GatewayAndSelfIP returns the current network's default gateway, and
// the machine's default IP for that gateway.
//
@@ -320,7 +336,11 @@ func (m *Monitor) notifyRuleDeleted(rdm ipRuleDeletedMessage) {
// considered when checking for network state changes.
// The ips parameter should be the IPs of the provided interface.
func (m *Monitor) isInterestingInterface(i interfaces.Interface, ips []netip.Prefix) bool {
return m.om.IsInterestingInterface(i.Name) && interfaces.UseInterestingInterfaces(i, ips)
if !m.om.IsInterestingInterface(i.Name) {
return false
}
return true
}
// debounce calls the callback function with a delay between events
@@ -358,18 +378,19 @@ func (m *Monitor) handlePotentialChange(newState *interfaces.State, forceCallbac
defer m.mu.Unlock()
oldState := m.ifState
timeJumped := shouldMonitorTimeJump && m.checkWallTimeAdvanceLocked()
if !timeJumped && !forceCallbacks && oldState.EqualFiltered(newState, interfaces.UseAllInterfaces, interfaces.UseAllIPs) {
if !timeJumped && !forceCallbacks && oldState.Equal(newState) {
// Exactly equal. Nothing to do.
return
}
delta := &ChangeDelta{
Monitor: m,
Old: oldState,
New: newState,
TimeJumped: timeJumped,
}
delta.Major = !newState.EqualFiltered(oldState, m.isInterestingInterface, interfaces.UseInterestingIPs)
delta.Major = m.IsMajorChangeFrom(oldState, newState)
if delta.Major {
m.gwValid = false
m.ifState = newState
@@ -394,6 +415,79 @@ func (m *Monitor) handlePotentialChange(newState *interfaces.State, forceCallbac
}
}
// IsMajorChangeFrom reports whether the transition from s1 to s2 is
// a "major" change, where major roughly means it's worth tearing down
// a bunch of connections and rebinding.
//
// TODO(bradiftz): tigten this definition.
func (m *Monitor) IsMajorChangeFrom(s1, s2 *interfaces.State) bool {
if s1 == nil && s2 == nil {
return false
}
if s1 == nil || s2 == nil {
return true
}
if s1.HaveV6 != s2.HaveV6 ||
s1.HaveV4 != s2.HaveV4 ||
s1.IsExpensive != s2.IsExpensive ||
s1.DefaultRouteInterface != s2.DefaultRouteInterface ||
s1.HTTPProxy != s2.HTTPProxy ||
s1.PAC != s2.PAC {
return true
}
for iname, i := range s1.Interface {
if iname == m.tsIfName {
// Ignore changes in the Tailscale interface itself.
continue
}
ips := s1.InterfaceIPs[iname]
if !m.isInterestingInterface(i, ips) {
continue
}
i2, ok := s2.Interface[iname]
if !ok {
return true
}
ips2, ok := s2.InterfaceIPs[iname]
if !ok {
return true
}
if !i.Equal(i2) || !prefixesMajorEqual(ips, ips2) {
return true
}
}
return false
}
// prefixesMajorEqual reports whether a and b are equal after ignoring
// boring things like link-local, loopback, and multicast addresses.
func prefixesMajorEqual(a, b []netip.Prefix) bool {
// trim returns a subslice of p with link local unicast,
// loopback, and multicast prefixes removed from the front.
trim := func(p []netip.Prefix) []netip.Prefix {
for len(p) > 0 {
a := p[0].Addr()
if a.IsLinkLocalUnicast() || a.IsLoopback() || a.IsMulticast() {
p = p[1:]
continue
}
break
}
return p
}
for {
a = trim(a)
b = trim(b)
if len(a) == 0 || len(b) == 0 {
return len(a) == 0 && len(b) == 0
}
if a[0] != b[0] {
return false
}
a, b = a[1:], b[1:]
}
}
func jsonSummary(x any) any {
j, err := json.Marshal(x)
if err != nil {
net/netmon/netmon_test.go
+132
View File
@@ -5,9 +5,14 @@ package netmon
import (
"flag"
"net"
"net/netip"
"sync/atomic"
"testing"
"time"
"tailscale.com/net/interfaces"
"tailscale.com/util/mak"
)
func TestMonitorStartClose(t *testing.T) {
@@ -108,3 +113,130 @@ func TestMonitorMode(t *testing.T) {
t.Logf("%v callbacks", n)
}
}
// tests (*State).IsMajorChangeFrom
func TestIsMajorChangeFrom(t *testing.T) {
type State = interfaces.State
type Interface = interfaces.Interface
tests := []struct {
name string
s1, s2 *State
want bool
}{
{
name: "eq_nil",
want: false,
},
{
name: "nil_mix",
s2: new(State),
want: true,
},
{
name: "eq",
s1: &State{
DefaultRouteInterface: "foo",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {netip.MustParsePrefix("10.0.1.2/16")},
},
},
s2: &State{
DefaultRouteInterface: "foo",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {netip.MustParsePrefix("10.0.1.2/16")},
},
},
want: false,
},
{
name: "default-route-changed",
s1: &State{
DefaultRouteInterface: "foo",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {netip.MustParsePrefix("10.0.1.2/16")},
},
},
s2: &State{
DefaultRouteInterface: "bar",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {netip.MustParsePrefix("10.0.1.2/16")},
},
},
want: true,
},
{
name: "some-interesting-ip-changed",
s1: &State{
DefaultRouteInterface: "foo",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {netip.MustParsePrefix("10.0.1.2/16")},
},
},
s2: &State{
DefaultRouteInterface: "foo",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {netip.MustParsePrefix("10.0.1.3/16")},
},
},
want: true,
},
{
name: "ipv6-ula-addressed-appeared",
s1: &State{
DefaultRouteInterface: "foo",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {netip.MustParsePrefix("10.0.1.2/16")},
},
},
s2: &State{
DefaultRouteInterface: "foo",
InterfaceIPs: map[string][]netip.Prefix{
"foo": {
netip.MustParsePrefix("10.0.1.2/16"),
// Brad saw this address coming & going on his home LAN, possibly
// via an Apple TV Thread routing advertisement? (Issue 9040)
netip.MustParsePrefix("fd15:bbfa:c583:4fce:f4fb:4ff:fe1a:4148/64"),
},
},
},
want: true, // TODO(bradfitz): want false (ignore the IPv6 ULA address on foo)
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
// Populate dummy interfaces where missing.
for _, s := range []*State{tt.s1, tt.s2} {
if s == nil {
continue
}
for name := range s.InterfaceIPs {
if _, ok := s.Interface[name]; !ok {
mak.Set(&s.Interface, name, Interface{Interface: &net.Interface{
Name: name,
}})
}
}
}
var m Monitor
m.om = &testOSMon{
Interesting: func(name string) bool { return true },
}
if got := m.IsMajorChangeFrom(tt.s1, tt.s2); got != tt.want {
t.Errorf("IsMajorChange = %v; want %v", got, tt.want)
}
})
}
}
type testOSMon struct {
osMon
Interesting func(name string) bool
}
func (m *testOSMon) IsInterestingInterface(name string) bool {
if m.Interesting == nil {
return true
}
return m.Interesting(name)
}