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// Copyright 2020 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 (
"net"
"unsafe"
"golang.org/x/net/internal/iana"
"golang.org/x/net/internal/socket"
"golang.org/x/sys/unix"
)
func marshalPacketInfo(b []byte, cm *ControlMessage) []byte {
m := socket.ControlMessage(b)
m.MarshalHeader(iana.ProtocolIP, unix.IP_PKTINFO, sizeofInetPktinfo)
if cm != nil {
pi := (*inetPktinfo)(unsafe.Pointer(&m.Data(sizeofInetPktinfo)[0]))
if ip := cm.Src.To4(); ip != nil {
copy(pi.Addr[:], ip)
}
if cm.IfIndex > 0 {
pi.setIfindex(cm.IfIndex)
}
}
return m.Next(sizeofInetPktinfo)
}
func parsePacketInfo(cm *ControlMessage, b []byte) {
pi := (*inetPktinfo)(unsafe.Pointer(&b[0]))
cm.IfIndex = int(pi.Ifindex)
if len(cm.Dst) < net.IPv4len {
cm.Dst = make(net.IP, net.IPv4len)
}
copy(cm.Dst, pi.Addr[:])
}
func setControlMessage(c *socket.Conn, opt *rawOpt, cf ControlFlags, on bool) error {
opt.Lock()
defer opt.Unlock()
if so, ok := sockOpts[ssoReceiveTTL]; ok && cf&FlagTTL != 0 {
if err := so.SetInt(c, boolint(on)); err != nil {
return err
}
if on {
opt.set(FlagTTL)
} else {
opt.clear(FlagTTL)
}
}
if so, ok := sockOpts[ssoPacketInfo]; ok {
if cf&(FlagSrc|FlagDst|FlagInterface) != 0 {
if err := so.SetInt(c, boolint(on)); err != nil {
return err
}
if on {
opt.set(cf & (FlagSrc | FlagDst | FlagInterface))
} else {
opt.clear(cf & (FlagSrc | FlagDst | FlagInterface))
}
}
} else {
if so, ok := sockOpts[ssoReceiveDst]; ok && cf&FlagDst != 0 {
if err := so.SetInt(c, boolint(on)); err != nil {
return err
}
if on {
opt.set(FlagDst)
} else {
opt.clear(FlagDst)
}
}
if so, ok := sockOpts[ssoReceiveInterface]; ok && cf&FlagInterface != 0 {
if err := so.SetInt(c, boolint(on)); err != nil {
return err
}
if on {
opt.set(FlagInterface)
} else {
opt.clear(FlagInterface)
}
}
}
return nil
}
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