vendor/golang.org/x/net/ipv4/control_unix.go

   1 // Copyright 2012 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 dragonfly freebsd linux netbsd openbsd solaris
   6
   7 package ipv4
   8
   9 import (
  10         "unsafe"
  11
  12         "golang.org/x/net/internal/iana"
  13         "golang.org/x/net/internal/socket"
  14 )
  15
  16 func setControlMessage(c *socket.Conn, opt *rawOpt, cf ControlFlags, on bool) error {
  17         opt.Lock()
  18         defer opt.Unlock()
  19         if so, ok := sockOpts[ssoReceiveTTL]; ok && cf&FlagTTL != 0 {
  20                 if err := so.SetInt(c, boolint(on)); err != nil {
  21                         return err
  22                 }
  23                 if on {
  24                         opt.set(FlagTTL)
  25                 } else {
  26                         opt.clear(FlagTTL)
  27                 }
  28         }
  29         if so, ok := sockOpts[ssoPacketInfo]; ok {
  30                 if cf&(FlagSrc|FlagDst|FlagInterface) != 0 {
  31                         if err := so.SetInt(c, boolint(on)); err != nil {
  32                                 return err
  33                         }
  34                         if on {
  35                                 opt.set(cf & (FlagSrc | FlagDst | FlagInterface))
  36                         } else {
  37                                 opt.clear(cf & (FlagSrc | FlagDst | FlagInterface))
  38                         }
  39                 }
  40         } else {
  41                 if so, ok := sockOpts[ssoReceiveDst]; ok && cf&FlagDst != 0 {
  42                         if err := so.SetInt(c, boolint(on)); err != nil {
  43                                 return err
  44                         }
  45                         if on {
  46                                 opt.set(FlagDst)
  47                         } else {
  48                                 opt.clear(FlagDst)
  49                         }
  50                 }
  51                 if so, ok := sockOpts[ssoReceiveInterface]; ok && cf&FlagInterface != 0 {
  52                         if err := so.SetInt(c, boolint(on)); err != nil {
  53                                 return err
  54                         }
  55                         if on {
  56                                 opt.set(FlagInterface)
  57                         } else {
  58                                 opt.clear(FlagInterface)
  59                         }
  60                 }
  61         }
  62         return nil
  63 }
  64
  65 func marshalTTL(b []byte, cm *ControlMessage) []byte {
  66         m := socket.ControlMessage(b)
  67         m.MarshalHeader(iana.ProtocolIP, sysIP_RECVTTL, 1)
  68         return m.Next(1)
  69 }
  70
  71 func parseTTL(cm *ControlMessage, b []byte) {
  72         cm.TTL = int(*(*byte)(unsafe.Pointer(&b[:1][0])))
  73 }