go.net/ipv6: make it work with Go 1.1
This CL makes use of built-in syscall stuff to allow go.net/ipv6
to work together with Go 1.1. Also it's able to improve the package
without churning the Go standard library.
Fixes golang/go#6548.
R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/15040044
diff --git a/ipv6/control_rfc2292_unix.go b/ipv6/control_rfc2292_unix.go
new file mode 100644
index 0000000..eef3968
--- /dev/null
+++ b/ipv6/control_rfc2292_unix.go
@@ -0,0 +1,153 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin
+
+package ipv6
+
+import (
+ "net"
+ "os"
+ "syscall"
+ "unsafe"
+)
+
+const pktinfo = FlagDst | FlagInterface
+
+func setControlMessage(fd int, opt *rawOpt, cf ControlFlags, on bool) error {
+ opt.Lock()
+ defer opt.Unlock()
+ if cf&FlagHopLimit != 0 {
+ if err := setIPv6ReceiveHopLimit(fd, on); err != nil {
+ return err
+ }
+ if on {
+ opt.set(FlagHopLimit)
+ } else {
+ opt.clear(FlagHopLimit)
+ }
+ }
+ if cf&pktinfo != 0 {
+ if err := setIPv6ReceivePacketInfo(fd, on); err != nil {
+ return err
+ }
+ if on {
+ opt.set(cf & pktinfo)
+ } else {
+ opt.clear(cf & pktinfo)
+ }
+ }
+ return nil
+}
+
+func newControlMessage(opt *rawOpt) (oob []byte) {
+ opt.Lock()
+ defer opt.Unlock()
+ l, off := 0, 0
+ if opt.isset(FlagHopLimit) {
+ l += syscall.CmsgSpace(4)
+ }
+ if opt.isset(pktinfo) {
+ l += syscall.CmsgSpace(sysSizeofPacketInfo)
+ }
+ if l > 0 {
+ oob = make([]byte, l)
+ if opt.isset(FlagHopLimit) {
+ m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+ m.Level = ianaProtocolIPv6
+ m.Type = sysSockopt2292HopLimit
+ m.SetLen(syscall.CmsgLen(4))
+ off += syscall.CmsgSpace(4)
+ }
+ if opt.isset(pktinfo) {
+ m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+ m.Level = ianaProtocolIPv6
+ m.Type = sysSockopt2292PacketInfo
+ m.SetLen(syscall.CmsgLen(sysSizeofPacketInfo))
+ off += syscall.CmsgSpace(sysSizeofPacketInfo)
+ }
+ }
+ return
+}
+
+func parseControlMessage(b []byte) (*ControlMessage, error) {
+ if len(b) == 0 {
+ return nil, nil
+ }
+ cmsgs, err := syscall.ParseSocketControlMessage(b)
+ if err != nil {
+ return nil, os.NewSyscallError("parse socket control message", err)
+ }
+ cm := &ControlMessage{}
+ for _, m := range cmsgs {
+ if m.Header.Level != ianaProtocolIPv6 {
+ continue
+ }
+ switch m.Header.Type {
+ case sysSockopt2292HopLimit:
+ cm.HopLimit = int(*(*byte)(unsafe.Pointer(&m.Data[:1][0])))
+ case sysSockopt2292PacketInfo:
+ pi := (*sysPacketInfo)(unsafe.Pointer(&m.Data[0]))
+ cm.IfIndex = int(pi.IfIndex)
+ cm.Dst = pi.IP[:]
+ }
+ }
+ return cm, nil
+}
+
+func marshalControlMessage(cm *ControlMessage) (oob []byte) {
+ if cm == nil {
+ return
+ }
+ l, off := 0, 0
+ if cm.HopLimit > 0 {
+ l += syscall.CmsgSpace(4)
+ }
+ pion := false
+ if cm.Src.To4() == nil && cm.Src.To16() != nil || cm.IfIndex != 0 {
+ pion = true
+ l += syscall.CmsgSpace(sysSizeofPacketInfo)
+ }
+ if len(cm.NextHop) == net.IPv6len {
+ l += syscall.CmsgSpace(syscall.SizeofSockaddrInet6)
+ }
+ if l > 0 {
+ oob = make([]byte, l)
+ if cm.HopLimit > 0 {
+ m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+ m.Level = ianaProtocolIPv6
+ m.Type = sysSockopt2292HopLimit
+ m.SetLen(syscall.CmsgLen(4))
+ data := oob[off+syscall.CmsgLen(0):]
+ *(*byte)(unsafe.Pointer(&data[:1][0])) = byte(cm.HopLimit)
+ off += syscall.CmsgSpace(4)
+ }
+ if pion {
+ m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+ m.Level = ianaProtocolIPv6
+ m.Type = sysSockopt2292PacketInfo
+ m.SetLen(syscall.CmsgLen(sysSizeofPacketInfo))
+ pi := (*sysPacketInfo)(unsafe.Pointer(&oob[off+syscall.CmsgLen(0)]))
+ if ip := cm.Src.To16(); ip != nil && ip.To4() == nil {
+ copy(pi.IP[:], ip)
+ }
+ if cm.IfIndex != 0 {
+ pi.IfIndex = uint32(cm.IfIndex)
+ }
+ off += syscall.CmsgSpace(sysSizeofPacketInfo)
+ }
+ if len(cm.NextHop) == net.IPv6len {
+ m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+ m.Level = ianaProtocolIPv6
+ m.Type = sysSockopt2292NextHop
+ m.SetLen(syscall.CmsgLen(syscall.SizeofSockaddrInet6))
+ sa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(&oob[off+syscall.CmsgLen(0)]))
+ sa.Len = syscall.SizeofSockaddrInet6
+ sa.Family = syscall.AF_INET6
+ copy(sa.Addr[:], cm.NextHop)
+ off += syscall.CmsgSpace(syscall.SizeofSockaddrInet6)
+ }
+ }
+ return
+}
