syscall: add if_announce support for openbsd

Update #4866.

R=golang-dev
CC=golang-dev
https://golang.org/cl/7382053

src/pkg/syscall/types_openbsd.go

@@ -187,11 +187,12 @@ type FdSet C.fd_set
 // Routing and interface messages
 
 const (
-	SizeofIfMsghdr  = C.sizeof_struct_if_msghdr
-	SizeofIfData    = C.sizeof_struct_if_data
-	SizeofIfaMsghdr = C.sizeof_struct_ifa_msghdr
-	SizeofRtMsghdr  = C.sizeof_struct_rt_msghdr
-	SizeofRtMetrics = C.sizeof_struct_rt_metrics
+	SizeofIfMsghdr         = C.sizeof_struct_if_msghdr
+	SizeofIfData           = C.sizeof_struct_if_data
+	SizeofIfaMsghdr        = C.sizeof_struct_ifa_msghdr
+	SizeofIfAnnounceMsghdr = C.sizeof_struct_if_announcemsghdr
+	SizeofRtMsghdr         = C.sizeof_struct_rt_msghdr
+	SizeofRtMetrics        = C.sizeof_struct_rt_metrics
 )
 
 type IfMsghdr C.struct_if_msghdr
@@ -200,6 +201,8 @@ type IfData C.struct_if_data
 
 type IfaMsghdr C.struct_ifa_msghdr
 
+type IfAnnounceMsghdr C.struct_if_announcemsghdr
+
 type RtMsghdr C.struct_rt_msghdr
 
 type RtMetrics C.struct_rt_metrics

src/pkg/syscall/zerrors_openbsd_386.go

@@ -441,6 +441,8 @@ const (
 	ICANON                            = 0x100
 	ICRNL                             = 0x100
 	IEXTEN                            = 0x400
+	IFAN_ARRIVAL                      = 0x0
+	IFAN_DEPARTURE                    = 0x1
 	IFA_ROUTE                         = 0x1
 	IFF_ALLMULTI                      = 0x200
 	IFF_BROADCAST                     = 0x2

src/pkg/syscall/zerrors_openbsd_amd64.go

@@ -447,6 +447,8 @@ const (
 	ICANON                            = 0x100
 	ICRNL                             = 0x100
 	IEXTEN                            = 0x400
+	IFAN_ARRIVAL                      = 0x0
+	IFAN_DEPARTURE                    = 0x1
 	IFA_ROUTE                         = 0x1
 	IFF_ALLMULTI                      = 0x200
 	IFF_BROADCAST                     = 0x2

src/pkg/syscall/ztypes_openbsd_386.go

@@ -260,11 +260,12 @@ type FdSet struct {
 }
 
 const (
-	SizeofIfMsghdr  = 0xe8
-	SizeofIfData    = 0xd0
-	SizeofIfaMsghdr = 0x18
-	SizeofRtMsghdr  = 0x58
-	SizeofRtMetrics = 0x30
+	SizeofIfMsghdr         = 0xe8
+	SizeofIfData           = 0xd0
+	SizeofIfaMsghdr        = 0x18
+	SizeofIfAnnounceMsghdr = 0x1a
+	SizeofRtMsghdr         = 0x58
+	SizeofRtMetrics        = 0x30
 )
 
 type IfMsghdr struct {
@@ -321,6 +322,16 @@ type IfaMsghdr struct {
 	Metric  int32
 }
 
+type IfAnnounceMsghdr struct {
+	Msglen  uint16
+	Version uint8
+	Type    uint8
+	Hdrlen  uint16
+	Index   uint16
+	What    uint16
+	Name    [16]int8
+}
+
 type RtMsghdr struct {
 	Msglen   uint16
 	Version  uint8

src/pkg/syscall/ztypes_openbsd_amd64.go

@@ -265,11 +265,12 @@ type FdSet struct {
 }
 
 const (
-	SizeofIfMsghdr  = 0xf8
-	SizeofIfData    = 0xe0
-	SizeofIfaMsghdr = 0x18
-	SizeofRtMsghdr  = 0x58
-	SizeofRtMetrics = 0x30
+	SizeofIfMsghdr         = 0xf8
+	SizeofIfData           = 0xe0
+	SizeofIfaMsghdr        = 0x18
+	SizeofIfAnnounceMsghdr = 0x1a
+	SizeofRtMsghdr         = 0x58
+	SizeofRtMetrics        = 0x30
 )
 
 type IfMsghdr struct {
@@ -328,6 +329,16 @@ type IfaMsghdr struct {
 	Metric  int32
 }
 
+type IfAnnounceMsghdr struct {
+	Msglen  uint16
+	Version uint8
+	Type    uint8
+	Hdrlen  uint16
+	Index   uint16
+	What    uint16
+	Name    [16]int8
+}
+
 type RtMsghdr struct {
 	Msglen   uint16
 	Version  uint8