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

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// 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 (
	"net"
	"time"

	"golang.org/x/net/internal/socket"
)

// BUG(mikio): On Windows, the JoinSourceSpecificGroup,
// LeaveSourceSpecificGroup, ExcludeSourceSpecificGroup and
// IncludeSourceSpecificGroup methods of PacketConn and RawConn are
// not implemented.

// A Conn represents a network endpoint that uses the IPv4 transport.
// It is used to control basic IP-level socket options such as TOS and
// TTL.
type Conn struct {
	genericOpt
}

type genericOpt struct {
	*socket.Conn
}

func (c *genericOpt) ok() bool { return c != nil && c.Conn != nil }

// NewConn returns a new Conn.
func NewConn(c net.Conn) *Conn {
	cc, _ := socket.NewConn(c)
	return &Conn{
		genericOpt: genericOpt{Conn: cc},
	}
}

// A PacketConn represents a packet network endpoint that uses the
// IPv4 transport. It is used to control several IP-level socket
// options including multicasting. It also provides datagram based
// network I/O methods specific to the IPv4 and higher layer protocols
// such as UDP.
type PacketConn struct {
	genericOpt
	dgramOpt
	payloadHandler
}

type dgramOpt struct {
	*socket.Conn
}

func (c *dgramOpt) ok() bool { return c != nil && c.Conn != nil }

// SetControlMessage sets the per packet IP-level socket options.
func (c *PacketConn) SetControlMessage(cf ControlFlags, on bool) error {
	if !c.payloadHandler.ok() {
		return errInvalidConn