diff --git a/ipv6/control_rfc2292_unix.go b/ipv6/control_rfc2292_unix.go
index dd5fdc3..2733ddb 100644
--- a/ipv6/control_rfc2292_unix.go
+++ b/ipv6/control_rfc2292_unix.go
@@ -12,11 +12,13 @@
 
 	"golang.org/x/net/internal/iana"
 	"golang.org/x/net/internal/socket"
+
+	"golang.org/x/sys/unix"
 )
 
 func marshal2292HopLimit(b []byte, cm *ControlMessage) []byte {
 	m := socket.ControlMessage(b)
-	m.MarshalHeader(iana.ProtocolIPv6, sysIPV6_2292HOPLIMIT, 4)
+	m.MarshalHeader(iana.ProtocolIPv6, unix.IPV6_2292HOPLIMIT, 4)
 	if cm != nil {
 		socket.NativeEndian.PutUint32(m.Data(4), uint32(cm.HopLimit))
 	}
@@ -25,7 +27,7 @@
 
 func marshal2292PacketInfo(b []byte, cm *ControlMessage) []byte {
 	m := socket.ControlMessage(b)
-	m.MarshalHeader(iana.ProtocolIPv6, sysIPV6_2292PKTINFO, sizeofInet6Pktinfo)
+	m.MarshalHeader(iana.ProtocolIPv6, unix.IPV6_2292PKTINFO, sizeofInet6Pktinfo)
 	if cm != nil {
 		pi := (*inet6Pktinfo)(unsafe.Pointer(&m.Data(sizeofInet6Pktinfo)[0]))
 		if ip := cm.Src.To16(); ip != nil && ip.To4() == nil {
@@ -40,7 +42,7 @@
 
 func marshal2292NextHop(b []byte, cm *ControlMessage) []byte {
 	m := socket.ControlMessage(b)
-	m.MarshalHeader(iana.ProtocolIPv6, sysIPV6_2292NEXTHOP, sizeofSockaddrInet6)
+	m.MarshalHeader(iana.ProtocolIPv6, unix.IPV6_2292NEXTHOP, sizeofSockaddrInet6)
 	if cm != nil {
 		sa := (*sockaddrInet6)(unsafe.Pointer(&m.Data(sizeofSockaddrInet6)[0]))
 		sa.setSockaddr(cm.NextHop, cm.IfIndex)
diff --git a/ipv6/defs_darwin.go b/ipv6/defs_darwin.go
index f2d9e85..6821c3f 100644
--- a/ipv6/defs_darwin.go
+++ b/ipv6/defs_darwin.go
@@ -17,72 +17,11 @@
 import "C"
 
 const (
-	sysIPV6_UNICAST_HOPS   = C.IPV6_UNICAST_HOPS
-	sysIPV6_MULTICAST_IF   = C.IPV6_MULTICAST_IF
-	sysIPV6_MULTICAST_HOPS = C.IPV6_MULTICAST_HOPS
-	sysIPV6_MULTICAST_LOOP = C.IPV6_MULTICAST_LOOP
-	sysIPV6_JOIN_GROUP     = C.IPV6_JOIN_GROUP
-	sysIPV6_LEAVE_GROUP    = C.IPV6_LEAVE_GROUP
-
-	sysIPV6_PORTRANGE    = C.IPV6_PORTRANGE
-	sysICMP6_FILTER      = C.ICMP6_FILTER
-	sysIPV6_2292PKTINFO  = C.IPV6_2292PKTINFO
-	sysIPV6_2292HOPLIMIT = C.IPV6_2292HOPLIMIT
-	sysIPV6_2292NEXTHOP  = C.IPV6_2292NEXTHOP
-	sysIPV6_2292HOPOPTS  = C.IPV6_2292HOPOPTS
-	sysIPV6_2292DSTOPTS  = C.IPV6_2292DSTOPTS
-	sysIPV6_2292RTHDR    = C.IPV6_2292RTHDR
-
-	sysIPV6_2292PKTOPTIONS = C.IPV6_2292PKTOPTIONS
-
-	sysIPV6_CHECKSUM = C.IPV6_CHECKSUM
-	sysIPV6_V6ONLY   = C.IPV6_V6ONLY
-
-	sysIPV6_IPSEC_POLICY = C.IPV6_IPSEC_POLICY
-
-	sysIPV6_RECVTCLASS = C.IPV6_RECVTCLASS
-	sysIPV6_TCLASS     = C.IPV6_TCLASS
-
-	sysIPV6_RTHDRDSTOPTS = C.IPV6_RTHDRDSTOPTS
-
-	sysIPV6_RECVPKTINFO = C.IPV6_RECVPKTINFO
-
-	sysIPV6_RECVHOPLIMIT = C.IPV6_RECVHOPLIMIT
-	sysIPV6_RECVRTHDR    = C.IPV6_RECVRTHDR
-	sysIPV6_RECVHOPOPTS  = C.IPV6_RECVHOPOPTS
-	sysIPV6_RECVDSTOPTS  = C.IPV6_RECVDSTOPTS
-
-	sysIPV6_USE_MIN_MTU = C.IPV6_USE_MIN_MTU
-	sysIPV6_RECVPATHMTU = C.IPV6_RECVPATHMTU
-
-	sysIPV6_PATHMTU = C.IPV6_PATHMTU
-
+	sysIPV6_TCLASS   = C.IPV6_TCLASS
+	sysIPV6_PATHMTU  = C.IPV6_PATHMTU
 	sysIPV6_PKTINFO  = C.IPV6_PKTINFO
 	sysIPV6_HOPLIMIT = C.IPV6_HOPLIMIT
 	sysIPV6_NEXTHOP  = C.IPV6_NEXTHOP
-	sysIPV6_HOPOPTS  = C.IPV6_HOPOPTS
-	sysIPV6_DSTOPTS  = C.IPV6_DSTOPTS
-	sysIPV6_RTHDR    = C.IPV6_RTHDR
-
-	sysIPV6_AUTOFLOWLABEL = C.IPV6_AUTOFLOWLABEL
-
-	sysIPV6_DONTFRAG = C.IPV6_DONTFRAG
-
-	sysIPV6_PREFER_TEMPADDR = C.IPV6_PREFER_TEMPADDR
-
-	sysIPV6_MSFILTER            = C.IPV6_MSFILTER
-	sysMCAST_JOIN_GROUP         = C.MCAST_JOIN_GROUP
-	sysMCAST_LEAVE_GROUP        = C.MCAST_LEAVE_GROUP
-	sysMCAST_JOIN_SOURCE_GROUP  = C.MCAST_JOIN_SOURCE_GROUP
-	sysMCAST_LEAVE_SOURCE_GROUP = C.MCAST_LEAVE_SOURCE_GROUP
-	sysMCAST_BLOCK_SOURCE       = C.MCAST_BLOCK_SOURCE
-	sysMCAST_UNBLOCK_SOURCE     = C.MCAST_UNBLOCK_SOURCE
-
-	sysIPV6_BOUND_IF = C.IPV6_BOUND_IF
-
-	sysIPV6_PORTRANGE_DEFAULT = C.IPV6_PORTRANGE_DEFAULT
-	sysIPV6_PORTRANGE_HIGH    = C.IPV6_PORTRANGE_HIGH
-	sysIPV6_PORTRANGE_LOW     = C.IPV6_PORTRANGE_LOW
 
 	sizeofSockaddrStorage = C.sizeof_struct_sockaddr_storage
 	sizeofSockaddrInet6   = C.sizeof_struct_sockaddr_in6
diff --git a/ipv6/sys_darwin.go b/ipv6/sys_darwin.go
index 12cc5cb..b80ec80 100644
--- a/ipv6/sys_darwin.go
+++ b/ipv6/sys_darwin.go
@@ -11,36 +11,38 @@
 
 	"golang.org/x/net/internal/iana"
 	"golang.org/x/net/internal/socket"
+
+	"golang.org/x/sys/unix"
 )
 
 var (
 	ctlOpts = [ctlMax]ctlOpt{
-		ctlTrafficClass: {sysIPV6_TCLASS, 4, marshalTrafficClass, parseTrafficClass},
-		ctlHopLimit:     {sysIPV6_HOPLIMIT, 4, marshalHopLimit, parseHopLimit},
-		ctlPacketInfo:   {sysIPV6_PKTINFO, sizeofInet6Pktinfo, marshalPacketInfo, parsePacketInfo},
-		ctlNextHop:      {sysIPV6_NEXTHOP, sizeofSockaddrInet6, marshalNextHop, parseNextHop},
-		ctlPathMTU:      {sysIPV6_PATHMTU, sizeofIPv6Mtuinfo, marshalPathMTU, parsePathMTU},
+		ctlTrafficClass: {unix.IPV6_TCLASS, 4, marshalTrafficClass, parseTrafficClass},
+		ctlHopLimit:     {unix.IPV6_HOPLIMIT, 4, marshalHopLimit, parseHopLimit},
+		ctlPacketInfo:   {unix.IPV6_PKTINFO, sizeofInet6Pktinfo, marshalPacketInfo, parsePacketInfo},
+		ctlNextHop:      {unix.IPV6_NEXTHOP, sizeofSockaddrInet6, marshalNextHop, parseNextHop},
+		ctlPathMTU:      {unix.IPV6_PATHMTU, sizeofIPv6Mtuinfo, marshalPathMTU, parsePathMTU},
 	}
 
 	sockOpts = map[int]*sockOpt{
-		ssoHopLimit:            {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_UNICAST_HOPS, Len: 4}},
-		ssoMulticastInterface:  {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_MULTICAST_IF, Len: 4}},
-		ssoMulticastHopLimit:   {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_MULTICAST_HOPS, Len: 4}},
-		ssoMulticastLoopback:   {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_MULTICAST_LOOP, Len: 4}},
-		ssoTrafficClass:        {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_TCLASS, Len: 4}},
-		ssoReceiveTrafficClass: {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_RECVTCLASS, Len: 4}},
-		ssoReceiveHopLimit:     {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_RECVHOPLIMIT, Len: 4}},
-		ssoReceivePacketInfo:   {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_RECVPKTINFO, Len: 4}},
-		ssoReceivePathMTU:      {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_RECVPATHMTU, Len: 4}},
-		ssoPathMTU:             {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_PATHMTU, Len: sizeofIPv6Mtuinfo}},
-		ssoChecksum:            {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysIPV6_CHECKSUM, Len: 4}},
-		ssoICMPFilter:          {Option: socket.Option{Level: iana.ProtocolIPv6ICMP, Name: sysICMP6_FILTER, Len: sizeofICMPv6Filter}},
-		ssoJoinGroup:           {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysMCAST_JOIN_GROUP, Len: sizeofGroupReq}, typ: ssoTypeGroupReq},
-		ssoLeaveGroup:          {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysMCAST_LEAVE_GROUP, Len: sizeofGroupReq}, typ: ssoTypeGroupReq},
-		ssoJoinSourceGroup:     {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysMCAST_JOIN_SOURCE_GROUP, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
-		ssoLeaveSourceGroup:    {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysMCAST_LEAVE_SOURCE_GROUP, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
-		ssoBlockSourceGroup:    {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysMCAST_BLOCK_SOURCE, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
-		ssoUnblockSourceGroup:  {Option: socket.Option{Level: iana.ProtocolIPv6, Name: sysMCAST_UNBLOCK_SOURCE, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
+		ssoHopLimit:            {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_UNICAST_HOPS, Len: 4}},
+		ssoMulticastInterface:  {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_MULTICAST_IF, Len: 4}},
+		ssoMulticastHopLimit:   {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_MULTICAST_HOPS, Len: 4}},
+		ssoMulticastLoopback:   {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_MULTICAST_LOOP, Len: 4}},
+		ssoTrafficClass:        {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_TCLASS, Len: 4}},
+		ssoReceiveTrafficClass: {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_RECVTCLASS, Len: 4}},
+		ssoReceiveHopLimit:     {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_RECVHOPLIMIT, Len: 4}},
+		ssoReceivePacketInfo:   {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_RECVPKTINFO, Len: 4}},
+		ssoReceivePathMTU:      {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_RECVPATHMTU, Len: 4}},
+		ssoPathMTU:             {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_PATHMTU, Len: sizeofIPv6Mtuinfo}},
+		ssoChecksum:            {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.IPV6_CHECKSUM, Len: 4}},
+		ssoICMPFilter:          {Option: socket.Option{Level: iana.ProtocolIPv6ICMP, Name: unix.ICMP6_FILTER, Len: sizeofICMPv6Filter}},
+		ssoJoinGroup:           {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.MCAST_JOIN_GROUP, Len: sizeofGroupReq}, typ: ssoTypeGroupReq},
+		ssoLeaveGroup:          {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.MCAST_LEAVE_GROUP, Len: sizeofGroupReq}, typ: ssoTypeGroupReq},
+		ssoJoinSourceGroup:     {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.MCAST_JOIN_SOURCE_GROUP, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
+		ssoLeaveSourceGroup:    {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.MCAST_LEAVE_SOURCE_GROUP, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
+		ssoBlockSourceGroup:    {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.MCAST_BLOCK_SOURCE, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
+		ssoUnblockSourceGroup:  {Option: socket.Option{Level: iana.ProtocolIPv6, Name: unix.MCAST_UNBLOCK_SOURCE, Len: sizeofGroupSourceReq}, typ: ssoTypeGroupSourceReq},
 	}
 )
 
diff --git a/ipv6/zsys_darwin.go b/ipv6/zsys_darwin.go
index 555744a..a121172 100644
--- a/ipv6/zsys_darwin.go
+++ b/ipv6/zsys_darwin.go
@@ -4,72 +4,11 @@
 package ipv6
 
 const (
-	sysIPV6_UNICAST_HOPS   = 0x4
-	sysIPV6_MULTICAST_IF   = 0x9
-	sysIPV6_MULTICAST_HOPS = 0xa
-	sysIPV6_MULTICAST_LOOP = 0xb
-	sysIPV6_JOIN_GROUP     = 0xc
-	sysIPV6_LEAVE_GROUP    = 0xd
-
-	sysIPV6_PORTRANGE    = 0xe
-	sysICMP6_FILTER      = 0x12
-	sysIPV6_2292PKTINFO  = 0x13
-	sysIPV6_2292HOPLIMIT = 0x14
-	sysIPV6_2292NEXTHOP  = 0x15
-	sysIPV6_2292HOPOPTS  = 0x16
-	sysIPV6_2292DSTOPTS  = 0x17
-	sysIPV6_2292RTHDR    = 0x18
-
-	sysIPV6_2292PKTOPTIONS = 0x19
-
-	sysIPV6_CHECKSUM = 0x1a
-	sysIPV6_V6ONLY   = 0x1b
-
-	sysIPV6_IPSEC_POLICY = 0x1c
-
-	sysIPV6_RECVTCLASS = 0x23
-	sysIPV6_TCLASS     = 0x24
-
-	sysIPV6_RTHDRDSTOPTS = 0x39
-
-	sysIPV6_RECVPKTINFO = 0x3d
-
-	sysIPV6_RECVHOPLIMIT = 0x25
-	sysIPV6_RECVRTHDR    = 0x26
-	sysIPV6_RECVHOPOPTS  = 0x27
-	sysIPV6_RECVDSTOPTS  = 0x28
-
-	sysIPV6_USE_MIN_MTU = 0x2a
-	sysIPV6_RECVPATHMTU = 0x2b
-
-	sysIPV6_PATHMTU = 0x2c
-
+	sysIPV6_TCLASS   = 0x24
+	sysIPV6_PATHMTU  = 0x2c
 	sysIPV6_PKTINFO  = 0x2e
 	sysIPV6_HOPLIMIT = 0x2f
 	sysIPV6_NEXTHOP  = 0x30
-	sysIPV6_HOPOPTS  = 0x31
-	sysIPV6_DSTOPTS  = 0x32
-	sysIPV6_RTHDR    = 0x33
-
-	sysIPV6_AUTOFLOWLABEL = 0x3b
-
-	sysIPV6_DONTFRAG = 0x3e
-
-	sysIPV6_PREFER_TEMPADDR = 0x3f
-
-	sysIPV6_MSFILTER            = 0x4a
-	sysMCAST_JOIN_GROUP         = 0x50
-	sysMCAST_LEAVE_GROUP        = 0x51
-	sysMCAST_JOIN_SOURCE_GROUP  = 0x52
-	sysMCAST_LEAVE_SOURCE_GROUP = 0x53
-	sysMCAST_BLOCK_SOURCE       = 0x54
-	sysMCAST_UNBLOCK_SOURCE     = 0x55
-
-	sysIPV6_BOUND_IF = 0x7d
-
-	sysIPV6_PORTRANGE_DEFAULT = 0x0
-	sysIPV6_PORTRANGE_HIGH    = 0x1
-	sysIPV6_PORTRANGE_LOW     = 0x2
 
 	sizeofSockaddrStorage = 0x80
 	sizeofSockaddrInet6   = 0x1c