unix: add IPMreqn and {Get,Set}sockoptIPMreqn on darwin

Change-Id: Id145cc8d86b71ff3ef603b5d0aae4bdd0e4c3f2b
Reviewed-on: https://go-review.googlesource.com/c/sys/+/312410
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/syscall_darwin.go

@@ -378,6 +378,17 @@ func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 	return
 }
 
+func GetsockoptIPMreqn(fd, level, opt int) (*IPMreqn, error) {
+	var value IPMreqn
+	vallen := _Socklen(SizeofIPMreqn)
+	errno := getsockopt(fd, level, opt, unsafe.Pointer(&value), &vallen)
+	return &value, errno
+}
+
+func SetsockoptIPMreqn(fd, level, opt int, mreq *IPMreqn) (err error) {
+	return setsockopt(fd, level, opt, unsafe.Pointer(mreq), unsafe.Sizeof(*mreq))
+}
+
 // GetsockoptXucred is a getsockopt wrapper that returns an Xucred struct.
 // The usual level and opt are SOL_LOCAL and LOCAL_PEERCRED, respectively.
 func GetsockoptXucred(fd, level, opt int) (*Xucred, error) {

unix/types_darwin.go

@@ -160,6 +160,8 @@ type Iovec C.struct_iovec
 
 type IPMreq C.struct_ip_mreq
 
+type IPMreqn C.struct_ip_mreqn
+
 type IPv6Mreq C.struct_ipv6_mreq
 
 type Msghdr C.struct_msghdr
@@ -185,6 +187,7 @@ const (
 	SizeofLinger           = C.sizeof_struct_linger
 	SizeofIovec            = C.sizeof_struct_iovec
 	SizeofIPMreq           = C.sizeof_struct_ip_mreq
+	SizeofIPMreqn          = C.sizeof_struct_ip_mreqn
 	SizeofIPv6Mreq         = C.sizeof_struct_ipv6_mreq
 	SizeofMsghdr           = C.sizeof_struct_msghdr
 	SizeofCmsghdr          = C.sizeof_struct_cmsghdr

unix/ztypes_darwin_386.go

@@ -221,6 +221,12 @@ type IPMreq struct {
 	Interface [4]byte /* in_addr */
 }
 
+type IPMreqn struct {
+	Multiaddr [4]byte /* in_addr */
+	Address   [4]byte /* in_addr */
+	Ifindex   int32
+}
+
 type IPv6Mreq struct {
 	Multiaddr [16]byte /* in6_addr */
 	Interface uint32
@@ -272,6 +278,7 @@ const (
 	SizeofLinger           = 0x8
 	SizeofIovec            = 0x8
 	SizeofIPMreq           = 0x8
+	SizeofIPMreqn          = 0xc
 	SizeofIPv6Mreq         = 0x14
 	SizeofMsghdr           = 0x1c
 	SizeofCmsghdr          = 0xc

unix/ztypes_darwin_amd64.go

@@ -233,6 +233,12 @@ type IPMreq struct {
 	Interface [4]byte /* in_addr */
 }
 
+type IPMreqn struct {
+	Multiaddr [4]byte /* in_addr */
+	Address   [4]byte /* in_addr */
+	Ifindex   int32
+}
+
 type IPv6Mreq struct {
 	Multiaddr [16]byte /* in6_addr */
 	Interface uint32
@@ -285,6 +291,7 @@ const (
 	SizeofLinger           = 0x8
 	SizeofIovec            = 0x10
 	SizeofIPMreq           = 0x8
+	SizeofIPMreqn          = 0xc
 	SizeofIPv6Mreq         = 0x14
 	SizeofMsghdr           = 0x30
 	SizeofCmsghdr          = 0xc

unix/ztypes_darwin_arm.go

@@ -221,6 +221,12 @@ type IPMreq struct {
 	Interface [4]byte /* in_addr */
 }
 
+type IPMreqn struct {
+	Multiaddr [4]byte /* in_addr */
+	Address   [4]byte /* in_addr */
+	Ifindex   int32
+}
+
 type IPv6Mreq struct {
 	Multiaddr [16]byte /* in6_addr */
 	Interface uint32
@@ -272,6 +278,7 @@ const (
 	SizeofLinger           = 0x8
 	SizeofIovec            = 0x8
 	SizeofIPMreq           = 0x8
+	SizeofIPMreqn          = 0xc
 	SizeofIPv6Mreq         = 0x14
 	SizeofMsghdr           = 0x1c
 	SizeofCmsghdr          = 0xc

unix/ztypes_darwin_arm64.go

@@ -233,6 +233,12 @@ type IPMreq struct {
 	Interface [4]byte /* in_addr */
 }
 
+type IPMreqn struct {
+	Multiaddr [4]byte /* in_addr */
+	Address   [4]byte /* in_addr */
+	Ifindex   int32
+}
+
 type IPv6Mreq struct {
 	Multiaddr [16]byte /* in6_addr */
 	Interface uint32
@@ -285,6 +291,7 @@ const (
 	SizeofLinger           = 0x8
 	SizeofIovec            = 0x10
 	SizeofIPMreq           = 0x8
+	SizeofIPMreqn          = 0xc
 	SizeofIPv6Mreq         = 0x14
 	SizeofMsghdr           = 0x30
 	SizeofCmsghdr          = 0xc