// Copyright 2009 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 net

import (
	
	
)

// BUG(mikio): On Plan 9, the ReadMsgUDP and
// WriteMsgUDP methods of UDPConn are not implemented.

// BUG(mikio): On Windows, the File method of UDPConn is not
// implemented.

// BUG(mikio): On JS, methods and functions related to UDPConn are not
// implemented.

// UDPAddr represents the address of a UDP end point.
type UDPAddr struct {
	IP   IP
	Port int
	Zone string // IPv6 scoped addressing zone
}

// Network returns the address's network name, "udp".
func ( *UDPAddr) () string { return "udp" }

func ( *UDPAddr) () string {
	if  == nil {
		return "<nil>"
	}
	 := ipEmptyString(.IP)
	if .Zone != "" {
		return JoinHostPort(+"%"+.Zone, itoa(.Port))
	}
	return JoinHostPort(, itoa(.Port))
}

func ( *UDPAddr) () bool {
	if  == nil || .IP == nil {
		return true
	}
	return .IP.IsUnspecified()
}

func ( *UDPAddr) () Addr {
	if  == nil {
		return nil
	}
	return 
}

// ResolveUDPAddr returns an address of UDP end point.
//
// The network must be a UDP network name.
//
// If the host in the address parameter is not a literal IP address or
// the port is not a literal port number, ResolveUDPAddr resolves the
// address to an address of UDP end point.
// Otherwise, it parses the address as a pair of literal IP address
// and port number.
// The address parameter can use a host name, but this is not
// recommended, because it will return at most one of the host name's
// IP addresses.
//
// See func Dial for a description of the network and address
// parameters.
func (,  string) (*UDPAddr, error) {
	switch  {
	case "udp", "udp4", "udp6":
	case "": // a hint wildcard for Go 1.0 undocumented behavior
		 = "udp"
	default:
		return nil, UnknownNetworkError()
	}
	,  := DefaultResolver.internetAddrList(context.Background(), , )
	if  != nil {
		return nil, 
	}
	return .forResolve(, ).(*UDPAddr), nil
}

// UDPConn is the implementation of the Conn and PacketConn interfaces
// for UDP network connections.
type UDPConn struct {
	conn
}

// SyscallConn returns a raw network connection.
// This implements the syscall.Conn interface.
func ( *UDPConn) () (syscall.RawConn, error) {
	if !.ok() {
		return nil, syscall.EINVAL
	}
	return newRawConn(.fd)
}

// ReadFromUDP acts like ReadFrom but returns a UDPAddr.
func ( *UDPConn) ( []byte) (int, *UDPAddr, error) {
	if !.ok() {
		return 0, nil, syscall.EINVAL
	}
	, ,  := .readFrom()
	if  != nil {
		 = &OpError{Op: "read", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return , , 
}

// ReadFrom implements the PacketConn ReadFrom method.
func ( *UDPConn) ( []byte) (int, Addr, error) {
	if !.ok() {
		return 0, nil, syscall.EINVAL
	}
	, ,  := .readFrom()
	if  != nil {
		 = &OpError{Op: "read", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	if  == nil {
		return , nil, 
	}
	return , , 
}

// ReadMsgUDP reads a message from c, copying the payload into b and
// the associated out-of-band data into oob. It returns the number of
// bytes copied into b, the number of bytes copied into oob, the flags
// that were set on the message and the source address of the message.
//
// The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
// used to manipulate IP-level socket options in oob.
func ( *UDPConn) (,  []byte) (, ,  int,  *UDPAddr,  error) {
	if !.ok() {
		return 0, 0, 0, nil, syscall.EINVAL
	}
	, , , ,  = .readMsg(, )
	if  != nil {
		 = &OpError{Op: "read", Net: .fd.net, Source: .fd.laddr, Addr: .fd.raddr, Err: }
	}
	return
}

// WriteToUDP acts like WriteTo but takes a UDPAddr.
func ( *UDPConn) ( []byte,  *UDPAddr) (int, error) {
	if !.ok() {
		return 0, syscall.EINVAL
	}
	,  := .writeTo(, )
	if  != nil {
		 = &OpError{Op: "write", Net: .fd.net, Source: .fd.laddr, Addr: .opAddr(), Err: }
	}
	return , 
}

// WriteTo implements the PacketConn WriteTo method.
func ( *UDPConn) ( []byte,  Addr) (int, error) {
	if !.ok() {
		return 0, syscall.EINVAL
	}
	,  := .(*UDPAddr)
	if ! {
		return 0, &OpError{Op: "write", Net: .fd.net, Source: .fd.laddr, Addr: , Err: syscall.EINVAL}
	}
	,  := .writeTo(, )
	if  != nil {
		 = &OpError{Op: "write", Net: .fd.net, Source: .fd.laddr, Addr: .opAddr(), Err: }
	}
	return , 
}

// WriteMsgUDP writes a message to addr via c if c isn't connected, or
// to c's remote address if c is connected (in which case addr must be
// nil). The payload is copied from b and the associated out-of-band
// data is copied from oob. It returns the number of payload and
// out-of-band bytes written.
//
// The packages golang.org/x/net/ipv4 and golang.org/x/net/ipv6 can be
// used to manipulate IP-level socket options in oob.
func ( *UDPConn) (,  []byte,  *UDPAddr) (,  int,  error) {
	if !.ok() {
		return 0, 0, syscall.EINVAL
	}
	, ,  = .writeMsg(, , )
	if  != nil {
		 = &OpError{Op: "write", Net: .fd.net, Source: .fd.laddr, Addr: .opAddr(), Err: }
	}
	return
}

func newUDPConn( *netFD) *UDPConn { return &UDPConn{conn{}} }

// DialUDP acts like Dial for UDP networks.
//
// The network must be a UDP network name; see func Dial for details.
//
// If laddr is nil, a local address is automatically chosen.
// If the IP field of raddr is nil or an unspecified IP address, the
// local system is assumed.
func ( string, ,  *UDPAddr) (*UDPConn, error) {
	switch  {
	case "udp", "udp4", "udp6":
	default:
		return nil, &OpError{Op: "dial", Net: , Source: .opAddr(), Addr: .opAddr(), Err: UnknownNetworkError()}
	}
	if  == nil {
		return nil, &OpError{Op: "dial", Net: , Source: .opAddr(), Addr: nil, Err: errMissingAddress}
	}
	 := &sysDialer{network: , address: .String()}
	,  := .dialUDP(context.Background(), , )
	if  != nil {
		return nil, &OpError{Op: "dial", Net: , Source: .opAddr(), Addr: .opAddr(), Err: }
	}
	return , nil
}

// ListenUDP acts like ListenPacket for UDP networks.
//
// The network must be a UDP network name; see func Dial for details.
//
// If the IP field of laddr is nil or an unspecified IP address,
// ListenUDP listens on all available IP addresses of the local system
// except multicast IP addresses.
// If the Port field of laddr is 0, a port number is automatically
// chosen.
func ( string,  *UDPAddr) (*UDPConn, error) {
	switch  {
	case "udp", "udp4", "udp6":
	default:
		return nil, &OpError{Op: "listen", Net: , Source: nil, Addr: .opAddr(), Err: UnknownNetworkError()}
	}
	if  == nil {
		 = &UDPAddr{}
	}
	 := &sysListener{network: , address: .String()}
	,  := .listenUDP(context.Background(), )
	if  != nil {
		return nil, &OpError{Op: "listen", Net: , Source: nil, Addr: .opAddr(), Err: }
	}
	return , nil
}

// ListenMulticastUDP acts like ListenPacket for UDP networks but
// takes a group address on a specific network interface.
//
// The network must be a UDP network name; see func Dial for details.
//
// ListenMulticastUDP listens on all available IP addresses of the
// local system including the group, multicast IP address.
// If ifi is nil, ListenMulticastUDP uses the system-assigned
// multicast interface, although this is not recommended because the
// assignment depends on platforms and sometimes it might require
// routing configuration.
// If the Port field of gaddr is 0, a port number is automatically
// chosen.
//
// ListenMulticastUDP is just for convenience of simple, small
// applications. There are golang.org/x/net/ipv4 and
// golang.org/x/net/ipv6 packages for general purpose uses.
//
// Note that ListenMulticastUDP will set the IP_MULTICAST_LOOP socket option
// to 0 under IPPROTO_IP, to disable loopback of multicast packets.
func ( string,  *Interface,  *UDPAddr) (*UDPConn, error) {
	switch  {
	case "udp", "udp4", "udp6":
	default:
		return nil, &OpError{Op: "listen", Net: , Source: nil, Addr: .opAddr(), Err: UnknownNetworkError()}
	}
	if  == nil || .IP == nil {
		return nil, &OpError{Op: "listen", Net: , Source: nil, Addr: .opAddr(), Err: errMissingAddress}
	}
	 := &sysListener{network: , address: .String()}
	,  := .listenMulticastUDP(context.Background(), , )
	if  != nil {
		return nil, &OpError{Op: "listen", Net: , Source: nil, Addr: .opAddr(), Err: }
	}
	return , nil
}