initial commit

vendor/golang.org/x/net/ipv6/control.go

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+// Copyright 2013 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 ipv6
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+)
+
+var (
+	errMissingAddress  = errors.New("missing address")
+	errInvalidConnType = errors.New("invalid conn type")
+	errNoSuchInterface = errors.New("no such interface")
+)
+
+// Note that RFC 3542 obsoletes RFC 2292 but OS X Snow Leopard and the
+// former still support RFC 2292 only.  Please be aware that almost
+// all protocol implementations prohibit using a combination of RFC
+// 2292 and RFC 3542 for some practical reasons.
+
+type rawOpt struct {
+	sync.RWMutex
+	cflags ControlFlags
+}
+
+func (c *rawOpt) set(f ControlFlags)        { c.cflags |= f }
+func (c *rawOpt) clear(f ControlFlags)      { c.cflags &^= f }
+func (c *rawOpt) isset(f ControlFlags) bool { return c.cflags&f != 0 }
+
+// A ControlFlags represents per packet basis IP-level socket option
+// control flags.
+type ControlFlags uint
+
+const (
+	FlagTrafficClass ControlFlags = 1 << iota // pass the traffic class on the received packet
+	FlagHopLimit                              // pass the hop limit on the received packet
+	FlagSrc                                   // pass the source address on the received packet
+	FlagDst                                   // pass the destination address on the received packet
+	FlagInterface                             // pass the interface index on the received packet
+	FlagPathMTU                               // pass the path MTU on the received packet path
+)
+
+const flagPacketInfo = FlagDst | FlagInterface
+
+// A ControlMessage represents per packet basis IP-level socket
+// options.
+type ControlMessage struct {
+	// Receiving socket options: SetControlMessage allows to
+	// receive the options from the protocol stack using ReadFrom
+	// method of PacketConn.
+	//
+	// Specifying socket options: ControlMessage for WriteTo
+	// method of PacketConn allows to send the options to the
+	// protocol stack.
+	//
+	TrafficClass int    // traffic class, must be 1 <= value <= 255 when specifying
+	HopLimit     int    // hop limit, must be 1 <= value <= 255 when specifying
+	Src          net.IP // source address, specifying only
+	Dst          net.IP // destination address, receiving only
+	IfIndex      int    // interface index, must be 1 <= value when specifying
+	NextHop      net.IP // next hop address, specifying only
+	MTU          int    // path MTU, receiving only
+}
+
+func (cm *ControlMessage) String() string {
+	if cm == nil {
+		return "<nil>"
+	}
+	return fmt.Sprintf("tclass: %#x, hoplim: %v, src: %v, dst: %v, ifindex: %v, nexthop: %v, mtu: %v", cm.TrafficClass, cm.HopLimit, cm.Src, cm.Dst, cm.IfIndex, cm.NextHop, cm.MTU)
+}
+
+// Ancillary data socket options
+const (
+	ctlTrafficClass = iota // header field
+	ctlHopLimit            // header field
+	ctlPacketInfo          // inbound or outbound packet path
+	ctlNextHop             // nexthop
+	ctlPathMTU             // path mtu
+	ctlMax
+)
+
+// A ctlOpt represents a binding for ancillary data socket option.
+type ctlOpt struct {
+	name    int // option name, must be equal or greater than 1
+	length  int // option length
+	marshal func([]byte, *ControlMessage) []byte
+	parse   func(*ControlMessage, []byte)
+}