// Copyright 2012 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. package ipv4 import ( "syscall" "unsafe") func setControlMessage(fd int, opt *rawOpt, cf ControlFlags, on bool) error { opt.Lock() defer opt.Unlock() if cf&FlagTTL != 0 { if err := setIPv4ReceiveTTL(fd, on); err != nil { return err } if on { opt.set(FlagTTL) } else { opt.clear(FlagTTL) } } if cf&(FlagSrc|FlagDst|FlagInterface) != 0 { if err := setIPv4PacketInfo(fd, on); err != nil { return err } if on { opt.set(cf & (FlagSrc | FlagDst | FlagInterface)) } else { opt.clear(cf & (FlagSrc | FlagDst | FlagInterface)) } } return nil} func (opt *rawOpt) oobLen() (l int) { if opt.isset(FlagTTL) { l += syscall.CmsgSpace(1) } if opt.isset(FlagSrc | FlagDst | FlagInterface) { l += syscall.CmsgSpace(sysSizeofPacketInfo) } return} func (opt *rawOpt) marshalControlMessage() (oob []byte) { var off int oob = make([]byte, opt.oobLen()) if opt.isset(FlagTTL) { m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off])) m.Level = ianaProtocolIP m.Type = sysSockoptReceiveTTL m.SetLen(syscall.CmsgLen(1)) off += syscall.CmsgSpace(1) } if opt.isset(FlagSrc | FlagDst | FlagInterface) { m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[0])) m.Level = ianaProtocolIP m.Type = sysSockoptPacketInfo m.SetLen(syscall.CmsgLen(sysSizeofPacketInfo)) off += syscall.CmsgSpace(sysSizeofPacketInfo) } return} func (cm *ControlMessage) oobLen() (l int) { if cm.Src.To4() != nil || cm.IfIndex != 0 { l += syscall.CmsgSpace(sysSizeofPacketInfo) } return} func (cm *ControlMessage) parseControlMessage(m *syscall.SocketControlMessage) { switch m.Header.Type { case sysSockoptTTL: cm.TTL = int(*(*byte)(unsafe.Pointer(&m.Data[:1][0]))) case sysSockoptPacketInfo: pi := (*sysPacketInfo)(unsafe.Pointer(&m.Data[0])) cm.IfIndex = int(pi.IfIndex) cm.Dst = pi.IP[:] }}
// Copyright 2012 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.
package ipv4
import (
"syscall"
"unsafe"
)
func setControlMessage(fd int, opt *rawOpt, cf ControlFlags, on bool) error {
opt.Lock()
defer opt.Unlock()
if cf&FlagTTL != 0 {
if err := setIPv4ReceiveTTL(fd, on); err != nil {
return err
}
if on {
opt.set(FlagTTL)
} else {
opt.clear(FlagTTL)
}
}
if cf&(FlagSrc|FlagDst|FlagInterface) != 0 {
if err := setIPv4PacketInfo(fd, on); err != nil {
return err
}
if on {
opt.set(cf & (FlagSrc | FlagDst | FlagInterface))
} else {
opt.clear(cf & (FlagSrc | FlagDst | FlagInterface))
}
}
return nil
}
func (opt *rawOpt) oobLen() (l int) {
if opt.isset(FlagTTL) {
l += syscall.CmsgSpace(1)
}
if opt.isset(FlagSrc | FlagDst | FlagInterface) {
l += syscall.CmsgSpace(sysSizeofPacketInfo)
}
return
}
func (opt *rawOpt) marshalControlMessage() (oob []byte) {
var off int
oob = make([]byte, opt.oobLen())
if opt.isset(FlagTTL) {
m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
m.Level = ianaProtocolIP
m.Type = sysSockoptReceiveTTL
m.SetLen(syscall.CmsgLen(1))
off += syscall.CmsgSpace(1)
}
if opt.isset(FlagSrc | FlagDst | FlagInterface) {
m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[0]))
m.Level = ianaProtocolIP
m.Type = sysSockoptPacketInfo
m.SetLen(syscall.CmsgLen(sysSizeofPacketInfo))
off += syscall.CmsgSpace(sysSizeofPacketInfo)
}
return
}
func (cm *ControlMessage) oobLen() (l int) {
if cm.Src.To4() != nil || cm.IfIndex != 0 {
l += syscall.CmsgSpace(sysSizeofPacketInfo)
}
return
}
func (cm *ControlMessage) parseControlMessage(m *syscall.SocketControlMessage) {
switch m.Header.Type {
case sysSockoptTTL:
cm.TTL = int(*(*byte)(unsafe.Pointer(&m.Data[:1][0])))
case sysSockoptPacketInfo:
pi := (*sysPacketInfo)(unsafe.Pointer(&m.Data[0]))
cm.IfIndex = int(pi.IfIndex)
cm.Dst = pi.IP[:]
}
}