| // Copyright 2014 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 linux solaris |
| |
| package ipv4 |
| |
| import ( |
| "net" |
| "unsafe" |
| |
| "golang.org/x/net/internal/iana" |
| "golang.org/x/net/internal/socket" |
| ) |
| |
| func marshalPacketInfo(b []byte, cm *ControlMessage) []byte { |
| m := socket.ControlMessage(b) |
| m.MarshalHeader(iana.ProtocolIP, sysIP_PKTINFO, sizeofInetPktinfo) |
| if cm != nil { |
| pi := (*inetPktinfo)(unsafe.Pointer(&m.Data(sizeofInetPktinfo)[0])) |
| if ip := cm.Src.To4(); ip != nil { |
| copy(pi.Spec_dst[:], 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[:]) |
| } |