David K. Bainbridge | 215e024 | 2017-09-05 23:18:24 -0700 | [diff] [blame] | 1 | // Copyright 2014 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // +build darwin linux solaris |
| 6 | |
| 7 | package ipv4 |
| 8 | |
| 9 | import ( |
| 10 | "net" |
| 11 | "unsafe" |
| 12 | |
| 13 | "golang.org/x/net/internal/iana" |
| 14 | "golang.org/x/net/internal/socket" |
| 15 | ) |
| 16 | |
| 17 | func marshalPacketInfo(b []byte, cm *ControlMessage) []byte { |
| 18 | m := socket.ControlMessage(b) |
| 19 | m.MarshalHeader(iana.ProtocolIP, sysIP_PKTINFO, sizeofInetPktinfo) |
| 20 | if cm != nil { |
| 21 | pi := (*inetPktinfo)(unsafe.Pointer(&m.Data(sizeofInetPktinfo)[0])) |
| 22 | if ip := cm.Src.To4(); ip != nil { |
| 23 | copy(pi.Spec_dst[:], ip) |
| 24 | } |
| 25 | if cm.IfIndex > 0 { |
| 26 | pi.setIfindex(cm.IfIndex) |
| 27 | } |
| 28 | } |
| 29 | return m.Next(sizeofInetPktinfo) |
| 30 | } |
| 31 | |
| 32 | func parsePacketInfo(cm *ControlMessage, b []byte) { |
| 33 | pi := (*inetPktinfo)(unsafe.Pointer(&b[0])) |
| 34 | cm.IfIndex = int(pi.Ifindex) |
| 35 | if len(cm.Dst) < net.IPv4len { |
| 36 | cm.Dst = make(net.IP, net.IPv4len) |
| 37 | } |
| 38 | copy(cm.Dst, pi.Addr[:]) |
| 39 | } |