[client] Ignore irrelevant route changes to tracked network monitor routes (#3796)

This commit is contained in:
Viktor Liu 2025-05-09 14:01:21 +02:00 committed by GitHub
parent cad2fe1f39
commit d5b52e86b6
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GPG Key ID: B5690EEEBB952194
6 changed files with 464 additions and 29 deletions

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@ -19,7 +19,7 @@ import (
func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop) error {
fd, err := unix.Socket(syscall.AF_ROUTE, syscall.SOCK_RAW, syscall.AF_UNSPEC)
if err != nil {
return fmt.Errorf("failed to open routing socket: %v", err)
return fmt.Errorf("open routing socket: %v", err)
}
defer func() {
err := unix.Close(fd)

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@ -13,7 +13,7 @@ import (
func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop) error {
routeMonitor, err := systemops.NewRouteMonitor(ctx)
if err != nil {
return fmt.Errorf("failed to create route monitor: %w", err)
return fmt.Errorf("create route monitor: %w", err)
}
defer func() {
if err := routeMonitor.Stop(); err != nil {
@ -38,35 +38,49 @@ func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop) er
}
func routeChanged(route systemops.RouteUpdate, nexthopv4, nexthopv6 systemops.Nexthop) bool {
intf := "<nil>"
if route.Interface != nil {
intf = route.Interface.Name
if isSoftInterface(intf) {
log.Debugf("Network monitor: ignoring default route change for soft interface %s", intf)
return false
}
if intf := route.NextHop.Intf; intf != nil && isSoftInterface(intf.Name) {
log.Debugf("Network monitor: ignoring default route change for next hop with soft interface %s", route.NextHop)
return false
}
// TODO: for the empty nexthop ip (on-link), determine the family differently
nexthop := nexthopv4
if route.NextHop.IP.Is6() {
nexthop = nexthopv6
}
switch route.Type {
case systemops.RouteModified:
// TODO: get routing table to figure out if our route is affected for modified routes
log.Infof("Network monitor: default route changed: via %s, interface %s", route.NextHop, intf)
return true
case systemops.RouteAdded:
if route.NextHop.Is4() && route.NextHop != nexthopv4.IP || route.NextHop.Is6() && route.NextHop != nexthopv6.IP {
log.Infof("Network monitor: default route added: via %s, interface %s", route.NextHop, intf)
return true
}
case systemops.RouteModified, systemops.RouteAdded:
return handleRouteAddedOrModified(route, nexthop)
case systemops.RouteDeleted:
if nexthopv4.Intf != nil && route.NextHop == nexthopv4.IP || nexthopv6.Intf != nil && route.NextHop == nexthopv6.IP {
log.Infof("Network monitor: default route removed: via %s, interface %s", route.NextHop, intf)
return true
}
return handleRouteDeleted(route, nexthop)
}
return false
}
func handleRouteAddedOrModified(route systemops.RouteUpdate, nexthop systemops.Nexthop) bool {
// For added/modified routes, we care about different next hops
if !nexthop.Equal(route.NextHop) {
action := "changed"
if route.Type == systemops.RouteAdded {
action = "added"
}
log.Infof("Network monitor: default route %s: via %s", action, route.NextHop)
return true
}
return false
}
func handleRouteDeleted(route systemops.RouteUpdate, nexthop systemops.Nexthop) bool {
// For deleted routes, we care about our tracked next hop being deleted
if nexthop.Equal(route.NextHop) {
log.Infof("Network monitor: default route removed: via %s", route.NextHop)
return true
}
return false
}
func isSoftInterface(name string) bool {
return strings.Contains(strings.ToLower(name), "isatap") || strings.Contains(strings.ToLower(name), "teredo")
}

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@ -0,0 +1,404 @@
package networkmonitor
import (
"net"
"net/netip"
"testing"
"github.com/stretchr/testify/assert"
"github.com/netbirdio/netbird/client/internal/routemanager/systemops"
)
func TestRouteChanged(t *testing.T) {
tests := []struct {
name string
route systemops.RouteUpdate
nexthopv4 systemops.Nexthop
nexthopv6 systemops.Nexthop
expected bool
}{
{
name: "soft interface should be ignored",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{
Name: "ISATAP-Interface", // isSoftInterface checks name
},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.2"),
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
},
expected: false,
},
{
name: "modified route with different v4 nexthop IP should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.2"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
},
expected: true,
},
{
name: "modified route with same v4 nexthop (IP and Intf Index) should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
},
expected: false,
},
{
name: "added route with different v6 nexthop IP should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteAdded,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::2"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
expected: true,
},
{
name: "added route with same v6 nexthop (IP and Intf Index) should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteAdded,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
expected: false,
},
{
name: "deleted route matching tracked v4 nexthop (IP and Intf Index) should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteDeleted,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
},
expected: true,
},
{
name: "deleted route not matching tracked v4 nexthop (different IP) should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteDeleted,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.3"), // Different IP
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{
Index: 1, Name: "eth0",
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
},
expected: false,
},
{
name: "modified v4 route with same IP, different Intf Index should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 2, Name: "eth1"}, // Different Intf Index
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: true,
},
{
name: "modified v4 route with same IP, one Intf nil, other non-nil should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: nil, // Intf is nil
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 1, Name: "eth0"}, // Tracked Intf is not nil
},
expected: true,
},
{
name: "added v4 route with same IP, different Intf Index should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteAdded,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 2, Name: "eth1"}, // Different Intf Index
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: true,
},
{
name: "deleted v4 route with same IP, different Intf Index should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteDeleted,
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{ // This is the route being deleted
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
},
nexthopv4: systemops.Nexthop{ // This is our tracked nexthop
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 2, Name: "eth1"}, // Different Intf Index
},
expected: false, // Because nexthopv4.Equal(route.NextHop) will be false
},
{
name: "modified v6 route with different IP, same Intf Index should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::3"), // Different IP
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: true,
},
{
name: "modified v6 route with same IP, different Intf Index should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 2, Name: "eth1"}, // Different Intf Index
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: true,
},
{
name: "modified v6 route with same IP, same Intf Index should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteModified,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: false,
},
{
name: "deleted v6 route matching tracked nexthop (IP and Intf Index) should return true",
route: systemops.RouteUpdate{
Type: systemops.RouteDeleted,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: true,
},
{
name: "deleted v6 route not matching tracked nexthop (different IP) should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteDeleted,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::3"), // Different IP
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
},
nexthopv6: systemops.Nexthop{
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: false,
},
{
name: "deleted v6 route not matching tracked nexthop (same IP, different Intf Index) should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteDeleted,
Destination: netip.PrefixFrom(netip.IPv6Unspecified(), 0),
NextHop: systemops.Nexthop{ // This is the route being deleted
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
},
nexthopv6: systemops.Nexthop{ // This is our tracked nexthop
IP: netip.MustParseAddr("2001:db8::1"),
Intf: &net.Interface{Index: 2, Name: "eth1"}, // Different Intf Index
},
expected: false,
},
{
name: "unknown route type should return false",
route: systemops.RouteUpdate{
Type: systemops.RouteUpdateType(99), // Unknown type
Destination: netip.PrefixFrom(netip.IPv4Unspecified(), 0),
NextHop: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.1"),
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
},
nexthopv4: systemops.Nexthop{
IP: netip.MustParseAddr("192.168.1.2"), // Different from route.NextHop
Intf: &net.Interface{Index: 1, Name: "eth0"},
},
expected: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
result := routeChanged(tt.route, tt.nexthopv4, tt.nexthopv6)
assert.Equal(t, tt.expected, result)
})
}
}
func TestIsSoftInterface(t *testing.T) {
tests := []struct {
name string
ifname string
expected bool
}{
{
name: "ISATAP interface should be detected",
ifname: "ISATAP tunnel adapter",
expected: true,
},
{
name: "lowercase soft interface should be detected",
ifname: "isatap.{14A5CF17-CA72-43EC-B4EA-B4B093641B7D}",
expected: true,
},
{
name: "Teredo interface should be detected",
ifname: "Teredo Tunneling Pseudo-Interface",
expected: true,
},
{
name: "regular interface should not be detected as soft",
ifname: "eth0",
expected: false,
},
{
name: "another regular interface should not be detected as soft",
ifname: "wlan0",
expected: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
result := isSoftInterface(tt.ifname)
assert.Equal(t, tt.expected, result)
})
}
}

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@ -118,9 +118,12 @@ func (nw *NetworkMonitor) Stop() {
}
func (nw *NetworkMonitor) checkChanges(ctx context.Context, event chan struct{}, nexthop4 systemops.Nexthop, nexthop6 systemops.Nexthop) {
defer close(event)
for {
if err := checkChangeFn(ctx, nexthop4, nexthop6); err != nil {
close(event)
if !errors.Is(err, context.Canceled) {
log.Errorf("Network monitor: failed to check for changes: %v", err)
}
return
}
// prevent blocking

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@ -1,6 +1,7 @@
package systemops
import (
"fmt"
"net"
"net/netip"
"sync"
@ -15,6 +16,20 @@ type Nexthop struct {
Intf *net.Interface
}
// Equal checks if two nexthops are equal.
func (n Nexthop) Equal(other Nexthop) bool {
return n.IP == other.IP && (n.Intf == nil && other.Intf == nil ||
n.Intf != nil && other.Intf != nil && n.Intf.Index == other.Intf.Index)
}
// String returns a string representation of the nexthop.
func (n Nexthop) String() string {
if n.Intf == nil {
return n.IP.String()
}
return fmt.Sprintf("%s @ %d (%s)", n.IP.String(), n.Intf.Index, n.Intf.Name)
}
type ExclusionCounter = refcounter.Counter[netip.Prefix, struct{}, Nexthop]
type SysOps struct {

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@ -33,8 +33,7 @@ type RouteUpdateType int
type RouteUpdate struct {
Type RouteUpdateType
Destination netip.Prefix
NextHop netip.Addr
Interface *net.Interface
NextHop Nexthop
}
// RouteMonitor provides a way to monitor changes in the routing table.
@ -231,15 +230,15 @@ func (rm *RouteMonitor) parseUpdate(row *MIB_IPFORWARD_ROW2, notificationType MI
intf, err := net.InterfaceByIndex(idx)
if err != nil {
log.Warnf("failed to get interface name for index %d: %v", idx, err)
update.Interface = &net.Interface{
update.NextHop.Intf = &net.Interface{
Index: idx,
}
} else {
update.Interface = intf
update.NextHop.Intf = intf
}
}
log.Tracef("Received route update with destination %v, next hop %v, interface %v", row.DestinationPrefix, row.NextHop, update.Interface)
log.Tracef("Received route update with destination %v, next hop %v, interface %v", row.DestinationPrefix, row.NextHop, update.NextHop.Intf)
dest := parseIPPrefix(row.DestinationPrefix, idx)
if !dest.Addr().IsValid() {
return RouteUpdate{}, fmt.Errorf("invalid destination: %v", row)
@ -262,7 +261,7 @@ func (rm *RouteMonitor) parseUpdate(row *MIB_IPFORWARD_ROW2, notificationType MI
update.Type = updateType
update.Destination = dest
update.NextHop = nexthop
update.NextHop.IP = nexthop
return update, nil
}