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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")
)
// References:
//
// RFC 2292 Advanced Sockets API for IPv6
// http://tools.ietf.org/html/rfc2292
// RFC 2460 Internet Protocol, Version 6 (IPv6) Specification
// http://tools.ietf.org/html/rfc2460
// RFC 3493 Basic Socket Interface Extensions for IPv6
// http://tools.ietf.org/html/rfc3493.html
// RFC 3542 Advanced Sockets Application Program Interface (API) for IPv6
// http://tools.ietf.org/html/rfc3542
//
// Note that RFC 3542 obsoltes 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.Mutex
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 reprensents 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
)
// 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)
}
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