[client] Replace windows network monitor implementation (#2450)

This new one uses functions from netioapi.h to monitor route changes.
This change ensures that we include routes that point to virtual
interfaces, such as vEthernet created by the Hyper-V Virtual Switch.
This commit is contained in:
Viktor Liu 2024-08-20 19:13:16 +02:00 committed by GitHub
parent 2a30db02bb
commit 80b0db80bc
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
4 changed files with 338 additions and 269 deletions

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@ -65,7 +65,7 @@ func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop, ca
continue
}
if !route.Dst.Addr().IsUnspecified() {
if route.Dst.Bits() != 0 {
continue
}

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@ -59,7 +59,7 @@ func (nw *NetworkMonitor) Start(ctx context.Context, callback func()) (err error
// recover in case sys ops panic
defer func() {
if r := recover(); r != nil {
err = fmt.Errorf("panic occurred: %v, stack trace: %s", r, string(debug.Stack()))
err = fmt.Errorf("panic occurred: %v, stack trace: %s", r, debug.Stack())
}
}()

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@ -3,252 +3,73 @@ package networkmonitor
import (
"context"
"fmt"
"net"
"net/netip"
"strings"
"time"
log "github.com/sirupsen/logrus"
"github.com/netbirdio/netbird/client/internal/routemanager/systemops"
)
const (
unreachable = 0
incomplete = 1
probe = 2
delay = 3
stale = 4
reachable = 5
permanent = 6
tbd = 7
)
const interval = 10 * time.Second
func checkChange(ctx context.Context, nexthopv4, nexthopv6 systemops.Nexthop, callback func()) error {
var neighborv4, neighborv6 *systemops.Neighbor
{
initialNeighbors, err := getNeighbors()
routeMonitor, err := systemops.NewRouteMonitor(ctx)
if err != nil {
return fmt.Errorf("get neighbors: %w", err)
return fmt.Errorf("failed to create route monitor: %w", err)
}
neighborv4 = assignNeighbor(nexthopv4, initialNeighbors)
neighborv6 = assignNeighbor(nexthopv6, initialNeighbors)
defer func() {
if err := routeMonitor.Stop(); err != nil {
log.Errorf("Network monitor: failed to stop route monitor: %v", err)
}
log.Debugf("Network monitor: initial IPv4 neighbor: %v, IPv6 neighbor: %v", neighborv4, neighborv6)
ticker := time.NewTicker(interval)
defer ticker.Stop()
}()
for {
select {
case <-ctx.Done():
return ErrStopped
case <-ticker.C:
if changed(nexthopv4, neighborv4, nexthopv6, neighborv6) {
case route := <-routeMonitor.RouteUpdates():
if route.Destination.Bits() != 0 {
continue
}
if routeChanged(route, nexthopv4, nexthopv6, callback) {
break
}
}
}
}
func routeChanged(route systemops.RouteUpdate, nexthopv4, nexthopv6 systemops.Nexthop, callback func()) 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
}
}
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)
go callback()
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)
go callback()
return nil
}
}
}
}
func assignNeighbor(nexthop systemops.Nexthop, initialNeighbors map[netip.Addr]systemops.Neighbor) *systemops.Neighbor {
if n, ok := initialNeighbors[nexthop.IP]; ok &&
n.State != unreachable &&
n.State != incomplete &&
n.State != tbd {
return &n
}
return nil
}
func changed(
nexthopv4 systemops.Nexthop,
neighborv4 *systemops.Neighbor,
nexthopv6 systemops.Nexthop,
neighborv6 *systemops.Neighbor,
) bool {
neighbors, err := getNeighbors()
if err != nil {
log.Errorf("network monitor: error fetching current neighbors: %v", err)
return false
}
if neighborChanged(nexthopv4, neighborv4, neighbors) || neighborChanged(nexthopv6, neighborv6, neighbors) {
return true
}
routes, err := getRoutes()
if err != nil {
log.Errorf("network monitor: error fetching current routes: %v", err)
return false
}
if routeChanged(nexthopv4, nexthopv4.Intf, routes) || routeChanged(nexthopv6, nexthopv6.Intf, routes) {
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)
go callback()
return true
}
return false
}
// routeChanged checks if the default routes still point to our nexthop/interface
func routeChanged(nexthop systemops.Nexthop, intf *net.Interface, routes []systemops.Route) bool {
if !nexthop.IP.IsValid() {
return false
}
if isSoftInterface(nexthop.Intf.Name) {
log.Tracef("network monitor: ignoring default route change for soft interface %s", nexthop.Intf.Name)
return false
}
unspec := getUnspecifiedPrefix(nexthop.IP)
defaultRoutes, foundMatchingRoute := processRoutes(nexthop, intf, routes, unspec)
log.Tracef("network monitor: all default routes:\n%s", strings.Join(defaultRoutes, "\n"))
if !foundMatchingRoute {
logRouteChange(nexthop.IP, intf)
return true
}
return false
}
func getUnspecifiedPrefix(ip netip.Addr) netip.Prefix {
if ip.Is6() {
return netip.PrefixFrom(netip.IPv6Unspecified(), 0)
}
return netip.PrefixFrom(netip.IPv4Unspecified(), 0)
}
func processRoutes(nexthop systemops.Nexthop, nexthopIntf *net.Interface, routes []systemops.Route, unspec netip.Prefix) ([]string, bool) {
var defaultRoutes []string
foundMatchingRoute := false
for _, r := range routes {
if r.Destination == unspec {
routeInfo := formatRouteInfo(r)
defaultRoutes = append(defaultRoutes, routeInfo)
if r.Nexthop == nexthop.IP && compareIntf(r.Interface, nexthopIntf) == 0 {
foundMatchingRoute = true
log.Debugf("network monitor: found matching default route: %s", routeInfo)
}
}
}
return defaultRoutes, foundMatchingRoute
}
func formatRouteInfo(r systemops.Route) string {
newIntf := "<nil>"
if r.Interface != nil {
newIntf = r.Interface.Name
}
return fmt.Sprintf("Nexthop: %s, Interface: %s", r.Nexthop, newIntf)
}
func logRouteChange(ip netip.Addr, intf *net.Interface) {
oldIntf := "<nil>"
if intf != nil {
oldIntf = intf.Name
}
log.Infof("network monitor: default route for %s (%s) is gone or changed", ip, oldIntf)
}
func neighborChanged(nexthop systemops.Nexthop, neighbor *systemops.Neighbor, neighbors map[netip.Addr]systemops.Neighbor) bool {
if neighbor == nil {
return false
}
// TODO: consider non-local nexthops, e.g. on point-to-point interfaces
if n, ok := neighbors[nexthop.IP]; ok {
if n.State == unreachable || n.State == incomplete {
log.Infof("network monitor: neighbor %s (%s) is not reachable: %s", neighbor.IPAddress, neighbor.LinkLayerAddress, stateFromInt(n.State))
return true
} else if n.InterfaceIndex != neighbor.InterfaceIndex {
log.Infof(
"network monitor: neighbor %s (%s) changed interface from '%s' (%d) to '%s' (%d): %s",
neighbor.IPAddress,
neighbor.LinkLayerAddress,
neighbor.InterfaceAlias,
neighbor.InterfaceIndex,
n.InterfaceAlias,
n.InterfaceIndex,
stateFromInt(n.State),
)
return true
}
} else {
log.Infof("network monitor: neighbor %s (%s) is gone", neighbor.IPAddress, neighbor.LinkLayerAddress)
return true
}
return false
}
func getNeighbors() (map[netip.Addr]systemops.Neighbor, error) {
entries, err := systemops.GetNeighbors()
if err != nil {
return nil, fmt.Errorf("get neighbors: %w", err)
}
neighbours := make(map[netip.Addr]systemops.Neighbor, len(entries))
for _, entry := range entries {
neighbours[entry.IPAddress] = entry
}
return neighbours, nil
}
func getRoutes() ([]systemops.Route, error) {
entries, err := systemops.GetRoutes()
if err != nil {
return nil, fmt.Errorf("get routes: %w", err)
}
return entries, nil
}
func stateFromInt(state uint8) string {
switch state {
case unreachable:
return "unreachable"
case incomplete:
return "incomplete"
case probe:
return "probe"
case delay:
return "delay"
case stale:
return "stale"
case reachable:
return "reachable"
case permanent:
return "permanent"
case tbd:
return "tbd"
default:
return "unknown"
}
}
func compareIntf(a, b *net.Interface) int {
switch {
case a == nil && b == nil:
return 0
case a == nil:
return -1
case b == nil:
return 1
default:
return a.Index - b.Index
}
}
func isSoftInterface(name string) bool {
return strings.Contains(strings.ToLower(name), "isatap") || strings.Contains(strings.ToLower(name), "teredo")
}

View File

@ -3,6 +3,8 @@
package systemops
import (
"context"
"encoding/binary"
"fmt"
"net"
"net/netip"
@ -11,15 +13,43 @@ import (
"strconv"
"strings"
"sync"
"syscall"
"time"
"unsafe"
log "github.com/sirupsen/logrus"
"github.com/yusufpapurcu/wmi"
"golang.org/x/sys/windows"
"github.com/netbirdio/netbird/client/firewall/uspfilter"
nbnet "github.com/netbirdio/netbird/util/net"
)
type RouteUpdateType int
// RouteUpdate represents a change in the routing table.
// The interface field contains the index only.
type RouteUpdate struct {
Type RouteUpdateType
Destination netip.Prefix
NextHop netip.Addr
Interface *net.Interface
}
// RouteMonitor provides a way to monitor changes in the routing table.
type RouteMonitor struct {
updates chan RouteUpdate
handle windows.Handle
done chan struct{}
}
// Route represents a single routing table entry.
type Route struct {
Destination netip.Prefix
Nexthop netip.Addr
Interface *net.Interface
}
type MSFT_NetRoute struct {
DestinationPrefix string
NextHop string
@ -28,33 +58,77 @@ type MSFT_NetRoute struct {
AddressFamily uint16
}
type Route struct {
Destination netip.Prefix
Nexthop netip.Addr
Interface *net.Interface
}
type MSFT_NetNeighbor struct {
IPAddress string
LinkLayerAddress string
State uint8
AddressFamily uint16
// MIB_IPFORWARD_ROW2 is defined in https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ns-netioapi-mib_ipforward_row2
type MIB_IPFORWARD_ROW2 struct {
InterfaceLuid uint64
InterfaceIndex uint32
InterfaceAlias string
DestinationPrefix IP_ADDRESS_PREFIX
NextHop SOCKADDR_INET_NEXTHOP
SitePrefixLength uint8
ValidLifetime uint32
PreferredLifetime uint32
Metric uint32
Protocol uint32
Loopback uint8
AutoconfigureAddress uint8
Publish uint8
Immortal uint8
Age uint32
Origin uint32
}
type Neighbor struct {
IPAddress netip.Addr
LinkLayerAddress string
State uint8
AddressFamily uint16
InterfaceIndex uint32
InterfaceAlias string
// IP_ADDRESS_PREFIX is defined in https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ns-netioapi-ip_address_prefix
type IP_ADDRESS_PREFIX struct {
Prefix SOCKADDR_INET
PrefixLength uint8
}
var prefixList []netip.Prefix
var lastUpdate time.Time
var mux = sync.Mutex{}
// SOCKADDR_INET is defined in https://learn.microsoft.com/en-us/windows/win32/api/ws2ipdef/ns-ws2ipdef-sockaddr_inet
// It represents the union of IPv4 and IPv6 socket addresses
type SOCKADDR_INET struct {
sin6_family int16
// nolint:unused
sin6_port uint16
// 4 bytes ipv4 or 4 bytes flowinfo + 16 bytes ipv6 + 4 bytes scope_id
data [24]byte
}
// SOCKADDR_INET_NEXTHOP is the same as SOCKADDR_INET but offset by 2 bytes
type SOCKADDR_INET_NEXTHOP struct {
// nolint:unused
pad [2]byte
sin6_family int16
// nolint:unused
sin6_port uint16
// 4 bytes ipv4 or 4 bytes flowinfo + 16 bytes ipv6 + 4 bytes scope_id
data [24]byte
}
// MIB_NOTIFICATION_TYPE is defined in https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ne-netioapi-mib_notification_type
type MIB_NOTIFICATION_TYPE int32
var (
modiphlpapi = windows.NewLazyDLL("iphlpapi.dll")
procNotifyRouteChange2 = modiphlpapi.NewProc("NotifyRouteChange2")
procCancelMibChangeNotify2 = modiphlpapi.NewProc("CancelMibChangeNotify2")
prefixList []netip.Prefix
lastUpdate time.Time
mux sync.Mutex
)
const (
MibParemeterModification MIB_NOTIFICATION_TYPE = iota
MibAddInstance
MibDeleteInstance
MibInitialNotification
)
const (
RouteModified RouteUpdateType = iota
RouteAdded
RouteDeleted
)
func (r *SysOps) SetupRouting(initAddresses []net.IP) (nbnet.AddHookFunc, nbnet.RemoveHookFunc, error) {
return r.setupRefCounter(initAddresses)
@ -94,6 +168,155 @@ func (r *SysOps) removeFromRouteTable(prefix netip.Prefix, nexthop Nexthop) erro
return nil
}
// NewRouteMonitor creates and starts a new RouteMonitor.
// It returns a pointer to the RouteMonitor and an error if the monitor couldn't be started.
func NewRouteMonitor(ctx context.Context) (*RouteMonitor, error) {
rm := &RouteMonitor{
updates: make(chan RouteUpdate, 5),
done: make(chan struct{}),
}
if err := rm.start(ctx); err != nil {
return nil, err
}
return rm, nil
}
func (rm *RouteMonitor) start(ctx context.Context) error {
if ctx.Err() != nil {
return ctx.Err()
}
callbackPtr := windows.NewCallback(func(callerContext uintptr, row *MIB_IPFORWARD_ROW2, notificationType MIB_NOTIFICATION_TYPE) uintptr {
if ctx.Err() != nil {
return 0
}
update, err := rm.parseUpdate(row, notificationType)
if err != nil {
log.Errorf("Failed to parse route update: %v", err)
return 0
}
select {
case <-rm.done:
return 0
case rm.updates <- update:
default:
log.Warn("Route update channel is full, dropping update")
}
return 0
})
var handle windows.Handle
if err := notifyRouteChange2(windows.AF_UNSPEC, callbackPtr, 0, false, &handle); err != nil {
return fmt.Errorf("NotifyRouteChange2 failed: %w", err)
}
rm.handle = handle
return nil
}
func (rm *RouteMonitor) parseUpdate(row *MIB_IPFORWARD_ROW2, notificationType MIB_NOTIFICATION_TYPE) (RouteUpdate, error) {
// destination prefix, next hop, interface index, interface luid are guaranteed to be there
// GetIpForwardEntry2 is not needed
var update RouteUpdate
idx := int(row.InterfaceIndex)
if idx != 0 {
intf, err := net.InterfaceByIndex(idx)
if err != nil {
return update, fmt.Errorf("get interface name: %w", err)
}
update.Interface = intf
}
log.Tracef("Received route update with destination %v, next hop %v, interface %v", row.DestinationPrefix, row.NextHop, update.Interface)
dest := parseIPPrefix(row.DestinationPrefix, idx)
if !dest.Addr().IsValid() {
return RouteUpdate{}, fmt.Errorf("invalid destination: %v", row)
}
nexthop := parseIPNexthop(row.NextHop, idx)
if !nexthop.IsValid() {
return RouteUpdate{}, fmt.Errorf("invalid next hop %v", row)
}
updateType := RouteModified
switch notificationType {
case MibParemeterModification:
updateType = RouteModified
case MibAddInstance:
updateType = RouteAdded
case MibDeleteInstance:
updateType = RouteDeleted
}
update.Type = updateType
update.Destination = dest
update.NextHop = nexthop
return update, nil
}
// Stop stops the RouteMonitor.
func (rm *RouteMonitor) Stop() error {
if rm.handle != 0 {
if err := cancelMibChangeNotify2(rm.handle); err != nil {
return fmt.Errorf("CancelMibChangeNotify2 failed: %w", err)
}
rm.handle = 0
}
close(rm.done)
close(rm.updates)
return nil
}
// RouteUpdates returns a channel that receives RouteUpdate messages.
func (rm *RouteMonitor) RouteUpdates() <-chan RouteUpdate {
return rm.updates
}
func notifyRouteChange2(family uint32, callback uintptr, callerContext uintptr, initialNotification bool, handle *windows.Handle) error {
var initNotif uint32
if initialNotification {
initNotif = 1
}
r1, _, e1 := syscall.SyscallN(
procNotifyRouteChange2.Addr(),
uintptr(family),
callback,
callerContext,
uintptr(initNotif),
uintptr(unsafe.Pointer(handle)),
)
if r1 != 0 {
if e1 != 0 {
return e1
}
return syscall.EINVAL
}
return nil
}
func cancelMibChangeNotify2(handle windows.Handle) error {
r1, _, e1 := syscall.SyscallN(procCancelMibChangeNotify2.Addr(), uintptr(handle))
if r1 != 0 {
if e1 != 0 {
return e1
}
return syscall.EINVAL
}
return nil
}
// GetRoutesFromTable returns the current routing table from with prefixes only.
// It ccaches the result for 2 seconds to avoid blocking the caller.
func GetRoutesFromTable() ([]netip.Prefix, error) {
mux.Lock()
defer mux.Unlock()
@ -117,6 +340,7 @@ func GetRoutesFromTable() ([]netip.Prefix, error) {
return prefixList, nil
}
// GetRoutes retrieves the current routing table using WMI.
func GetRoutes() ([]Route, error) {
var entries []MSFT_NetRoute
@ -146,8 +370,8 @@ func GetRoutes() ([]Route, error) {
Name: entry.InterfaceAlias,
}
if nexthop.Is6() && (nexthop.IsLinkLocalUnicast() || nexthop.IsLinkLocalMulticast()) {
nexthop = nexthop.WithZone(strconv.Itoa(int(entry.InterfaceIndex)))
if nexthop.Is6() {
nexthop = addZone(nexthop, int(entry.InterfaceIndex))
}
}
@ -161,33 +385,6 @@ func GetRoutes() ([]Route, error) {
return routes, nil
}
func GetNeighbors() ([]Neighbor, error) {
var entries []MSFT_NetNeighbor
query := `SELECT IPAddress, LinkLayerAddress, State, AddressFamily, InterfaceIndex, InterfaceAlias FROM MSFT_NetNeighbor`
if err := wmi.QueryNamespace(query, &entries, `ROOT\StandardCimv2`); err != nil {
return nil, fmt.Errorf("failed to query MSFT_NetNeighbor: %w", err)
}
var neighbors []Neighbor
for _, entry := range entries {
addr, err := netip.ParseAddr(entry.IPAddress)
if err != nil {
log.Warnf("Unable to parse neighbor IP address %s: %v", entry.IPAddress, err)
continue
}
neighbors = append(neighbors, Neighbor{
IPAddress: addr,
LinkLayerAddress: entry.LinkLayerAddress,
State: entry.State,
AddressFamily: entry.AddressFamily,
InterfaceIndex: entry.InterfaceIndex,
InterfaceAlias: entry.InterfaceAlias,
})
}
return neighbors, nil
}
func addRouteCmd(prefix netip.Prefix, nexthop Nexthop) error {
args := []string{"add", prefix.String()}
@ -220,3 +417,54 @@ func addRouteCmd(prefix netip.Prefix, nexthop Nexthop) error {
func isCacheDisabled() bool {
return os.Getenv("NB_DISABLE_ROUTE_CACHE") == "true"
}
func parseIPPrefix(prefix IP_ADDRESS_PREFIX, idx int) netip.Prefix {
ip := parseIP(prefix.Prefix, idx)
return netip.PrefixFrom(ip, int(prefix.PrefixLength))
}
func parseIP(addr SOCKADDR_INET, idx int) netip.Addr {
return parseIPGeneric(addr.sin6_family, addr.data, idx)
}
func parseIPNexthop(addr SOCKADDR_INET_NEXTHOP, idx int) netip.Addr {
return parseIPGeneric(addr.sin6_family, addr.data, idx)
}
func parseIPGeneric(family int16, data [24]byte, interfaceIndex int) netip.Addr {
switch family {
case windows.AF_INET:
ipv4 := binary.BigEndian.Uint32(data[:4])
return netip.AddrFrom4([4]byte{
byte(ipv4 >> 24),
byte(ipv4 >> 16),
byte(ipv4 >> 8),
byte(ipv4),
})
case windows.AF_INET6:
// The IPv6 address is stored after the 4-byte flowinfo field
var ipv6 [16]byte
copy(ipv6[:], data[4:20])
ip := netip.AddrFrom16(ipv6)
// Check if there's a non-zero scope_id
scopeID := binary.BigEndian.Uint32(data[20:24])
if scopeID != 0 {
ip = ip.WithZone(strconv.FormatUint(uint64(scopeID), 10))
} else if interfaceIndex != 0 {
ip = addZone(ip, interfaceIndex)
}
return ip
}
return netip.IPv4Unspecified()
}
func addZone(ip netip.Addr, interfaceIndex int) netip.Addr {
if ip.IsLinkLocalUnicast() || ip.IsLinkLocalMulticast() {
ip = ip.WithZone(strconv.Itoa(interfaceIndex))
}
return ip
}