bump(code.google.com/p/go.net): ca4c826193c2

third_party/code.google.com/p/go.net/ipv4/control_linux.go

@@ -0,0 +1,126 @@
+// 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 (
+	"os"
+	"syscall"
+	"unsafe"
+)
+
+// Linux provides a convenient path control option IP_PKTINFO that
+// contains IP_SENDSRCADDR, IP_RECVDSTADDR, IP_RECVIF and IP_SENDIF.
+const pktinfo = FlagSrc | FlagDst | FlagInterface
+
+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&pktinfo != 0 {
+		if err := setIPv4PacketInfo(fd, on); err != nil {
+			return err
+		}
+		if on {
+			opt.set(cf & pktinfo)
+		} else {
+			opt.clear(cf & pktinfo)
+		}
+	}
+	return nil
+}
+
+func newControlMessage(opt *rawOpt) (oob []byte) {
+	opt.Lock()
+	defer opt.Unlock()
+	l, off := 0, 0
+	if opt.isset(FlagTTL) {
+		l += syscall.CmsgSpace(1)
+	}
+	if opt.isset(pktinfo) {
+		l += syscall.CmsgSpace(syscall.SizeofInet4Pktinfo)
+	}
+	if l > 0 {
+		oob = make([]byte, l)
+		if opt.isset(FlagTTL) {
+			m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+			m.Level = ianaProtocolIP
+			m.Type = syscall.IP_RECVTTL
+			m.SetLen(syscall.CmsgLen(1))
+			off += syscall.CmsgSpace(1)
+		}
+		if opt.isset(pktinfo) {
+			m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+			m.Level = ianaProtocolIP
+			m.Type = syscall.IP_PKTINFO
+			m.SetLen(syscall.CmsgLen(syscall.SizeofInet4Pktinfo))
+			off += syscall.CmsgSpace(syscall.SizeofInet4Pktinfo)
+		}
+	}
+	return
+}
+
+func parseControlMessage(b []byte) (*ControlMessage, error) {
+	if len(b) == 0 {
+		return nil, nil
+	}
+	cmsgs, err := syscall.ParseSocketControlMessage(b)
+	if err != nil {
+		return nil, os.NewSyscallError("parse socket control message", err)
+	}
+	cm := &ControlMessage{}
+	for _, m := range cmsgs {
+		if m.Header.Level != ianaProtocolIP {
+			continue
+		}
+		switch m.Header.Type {
+		case syscall.IP_TTL:
+			cm.TTL = int(*(*byte)(unsafe.Pointer(&m.Data[:1][0])))
+		case syscall.IP_PKTINFO:
+			pi := (*syscall.Inet4Pktinfo)(unsafe.Pointer(&m.Data[0]))
+			cm.IfIndex = int(pi.Ifindex)
+			cm.Dst = pi.Addr[:]
+		}
+	}
+	return cm, nil
+}
+
+func marshalControlMessage(cm *ControlMessage) (oob []byte) {
+	if cm == nil {
+		return
+	}
+	l, off := 0, 0
+	pion := false
+	if cm.Src.To4() != nil || cm.IfIndex != 0 {
+		pion = true
+		l += syscall.CmsgSpace(syscall.SizeofInet4Pktinfo)
+	}
+	if l > 0 {
+		oob = make([]byte, l)
+		if pion {
+			m := (*syscall.Cmsghdr)(unsafe.Pointer(&oob[off]))
+			m.Level = ianaProtocolIP
+			m.Type = syscall.IP_PKTINFO
+			m.SetLen(syscall.CmsgLen(syscall.SizeofInet4Pktinfo))
+			pi := (*syscall.Inet4Pktinfo)(unsafe.Pointer(&oob[off+syscall.CmsgLen(0)]))
+			if ip := cm.Src.To4(); ip != nil {
+				copy(pi.Addr[:], ip)
+			}
+			if cm.IfIndex != 0 {
+				pi.Ifindex = int32(cm.IfIndex)
+			}
+			off += syscall.CmsgSpace(syscall.SizeofInet4Pktinfo)
+		}
+	}
+	return
+}