windows: add iphlpapi functions for change notifications

The NotifyIpInterfaceChange and NotifyUnicastIpAddressChange functions register a user-defined callback function for receiving network interface and IP address change notifications. The GetIfEntry2Ex and GetUnicastIpAddressEntry functions can be called to retrieve complete information about the changed interface or address.

The CancelMibChangeNotify2 function deregisters for change notifications.

Author: database64128

windows/syscall_windows.go

@@ -886,6 +886,11 @@ const socket_error = uintptr(^uint32(0))
 //sys	GetACP() (acp uint32) = kernel32.GetACP
 //sys	MultiByteToWideChar(codePage uint32, dwFlags uint32, str *byte, nstr int32, wchar *uint16, nwchar int32) (nwrite int32, err error) = kernel32.MultiByteToWideChar
 //sys	getBestInterfaceEx(sockaddr unsafe.Pointer, pdwBestIfIndex *uint32) (errcode error) = iphlpapi.GetBestInterfaceEx
+//sys   GetIfEntry2Ex(level uint32, row *MibIfRow2) (errcode error) = iphlpapi.GetIfEntry2Ex
+//sys   GetUnicastIpAddressEntry(row *MibUnicastIpAddressRow) (errcode error) = iphlpapi.GetUnicastIpAddressEntry
+//sys   NotifyIpInterfaceChange(family uint16, callback uintptr, callerContext unsafe.Pointer, initialNotification bool, notificationHandle *Handle) (errcode error) = iphlpapi.NotifyIpInterfaceChange
+//sys   NotifyUnicastIpAddressChange(family uint16, callback uintptr, callerContext unsafe.Pointer, initialNotification bool, notificationHandle *Handle) (errcode error) = iphlpapi.NotifyUnicastIpAddressChange
+//sys   CancelMibChangeNotify2(notificationHandle Handle) (errcode error) = iphlpapi.CancelMibChangeNotify2
 
 // For testing: clients can set this flag to force
 // creation of IPv6 sockets to return EAFNOSUPPORT.

windows/types_windows.go

@@ -2203,6 +2203,132 @@ const (
 	IfOperStatusLowerLayerDown = 7
 )
 
+const (
+	IF_MAX_PHYS_ADDRESS_LENGTH = 32
+	IF_MAX_STRING_SIZE         = 256
+)
+
+// MIB_IF_ENTRY_LEVEL enumeration from netioapi.h or
+// https://learn.microsoft.com/en-us/windows/win32/api/netioapi/nf-netioapi-getifentry2ex.
+const (
+	MibIfEntryNormal                  = 0
+	MibIfEntryNormalWithoutStatistics = 2
+)
+
+// MIB_NOTIFICATION_TYPE enumeration from netioapi.h or
+// https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ne-netioapi-mib_notification_type.
+const (
+	MibParameterNotification = 0
+	MibAddInstance           = 1
+	MibDeleteInstance        = 2
+	MibInitialNotification   = 3
+)
+
+// MibIfRow2 stores information about a particular interface. See
+// https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ns-netioapi-mib_if_row2.
+type MibIfRow2 struct {
+	InterfaceLuid               uint64
+	InterfaceIndex              uint32
+	InterfaceGuid               GUID
+	Alias                       [IF_MAX_STRING_SIZE + 1]uint16
+	Description                 [IF_MAX_STRING_SIZE + 1]uint16
+	PhysicalAddressLength       uint32
+	PhysicalAddress             [IF_MAX_PHYS_ADDRESS_LENGTH]uint8
+	PermanentPhysicalAddress    [IF_MAX_PHYS_ADDRESS_LENGTH]uint8
+	Mtu                         uint32
+	Type                        uint32
+	TunnelType                  uint32
+	MediaType                   uint32
+	PhysicalMediumType          uint32
+	AccessType                  uint32
+	DirectionType               uint32
+	InterfaceAndOperStatusFlags uint8
+	OperStatus                  uint32
+	AdminStatus                 uint32
+	MediaConnectState           uint32
+	NetworkGuid                 GUID
+	ConnectionType              uint32
+	TransmitLinkSpeed           uint64
+	ReceiveLinkSpeed            uint64
+	InOctets                    uint64
+	InUcastPkts                 uint64
+	InNUcastPkts                uint64
+	InDiscards                  uint64
+	InErrors                    uint64
+	InUnknownProtos             uint64
+	InUcastOctets               uint64
+	InMulticastOctets           uint64
+	InBroadcastOctets           uint64
+	OutOctets                   uint64
+	OutUcastPkts                uint64
+	OutNUcastPkts               uint64
+	OutDiscards                 uint64
+	OutErrors                   uint64
+	OutUcastOctets              uint64
+	OutMulticastOctets          uint64
+	OutBroadcastOctets          uint64
+	OutQLen                     uint64
+}
+
+// MIB_UNICASTIPADDRESS_ROW stores information about a unicast IP address. See
+// https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ns-netioapi-mib_unicastipaddress_row.
+type MibUnicastIpAddressRow struct {
+	Address            RawSockaddrInet6 // SOCKADDR_INET union
+	InterfaceLuid      uint64
+	InterfaceIndex     uint32
+	PrefixOrigin       uint32
+	SuffixOrigin       uint32
+	ValidLifetime      uint32
+	PreferredLifetime  uint32
+	OnLinkPrefixLength uint8
+	SkipAsSource       uint8
+	DadState           uint32
+	ScopeId            uint32
+	CreationTimeStamp  Filetime
+}
+
+const ScopeLevelCount = 16
+
+// MIB_IPINTERFACE_ROW stores interface management information for a particular IP address family on a network interface.
+// See https://learn.microsoft.com/en-us/windows/win32/api/netioapi/ns-netioapi-mib_ipinterface_row.
+type MibIpInterfaceRow struct {
+	Family                               uint16
+	InterfaceLuid                        uint64
+	InterfaceIndex                       uint32
+	MaxReassemblySize                    uint32
+	InterfaceIdentifier                  uint64
+	MinRouterAdvertisementInterval       uint32
+	MaxRouterAdvertisementInterval       uint32
+	AdvertisingEnabled                   uint8
+	ForwardingEnabled                    uint8
+	WeakHostSend                         uint8
+	WeakHostReceive                      uint8
+	UseAutomaticMetric                   uint8
+	UseNeighborUnreachabilityDetection   uint8
+	ManagedAddressConfigurationSupported uint8
+	OtherStatefulConfigurationSupported  uint8
+	AdvertiseDefaultRoute                uint8
+	RouterDiscoveryBehavior              uint32
+	DadTransmits                         uint32
+	BaseReachableTime                    uint32
+	RetransmitTime                       uint32
+	PathMtuDiscoveryTimeout              uint32
+	LinkLocalAddressBehavior             uint32
+	LinkLocalAddressTimeout              uint32
+	ZoneIndices                          [ScopeLevelCount]uint32
+	SitePrefixLength                     uint32
+	Metric                               uint32
+	NlMtu                                uint32
+	Connected                            uint8
+	SupportsWakeUpPatterns               uint8
+	SupportsNeighborDiscovery            uint8
+	SupportsRouterDiscovery              uint8
+	ReachableTime                        uint32
+	TransmitOffload                      uint32
+	ReceiveOffload                       uint32
+	DisableDefaultRoutes                 uint8
+}
+
 // Console related constants used for the mode parameter to SetConsoleMode. See
 // https://docs.microsoft.com/en-us/windows/console/setconsolemode for details.