// Copyright 2014 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 (
	
	
	
)

const (
	Version   = 6  // protocol version
	HeaderLen = 40 // header length
)

// A Header represents an IPv6 base header.
type Header struct {
	Version      int    // protocol version
	TrafficClass int    // traffic class
	FlowLabel    int    // flow label
	PayloadLen   int    // payload length
	NextHeader   int    // next header
	HopLimit     int    // hop limit
	Src          net.IP // source address
	Dst          net.IP // destination address
}

func ( *Header) () string {
	if  == nil {
		return "<nil>"
	}
	return fmt.Sprintf("ver=%d tclass=%#x flowlbl=%#x payloadlen=%d nxthdr=%d hoplim=%d src=%v dst=%v", .Version, .TrafficClass, .FlowLabel, .PayloadLen, .NextHeader, .HopLimit, .Src, .Dst)
}

// ParseHeader parses b as an IPv6 base header.
func ( []byte) (*Header, error) {
	if len() < HeaderLen {
		return nil, errHeaderTooShort
	}
	 := &Header{
		Version:      int([0]) >> 4,
		TrafficClass: int([0]&0x0f)<<4 | int([1])>>4,
		FlowLabel:    int([1]&0x0f)<<16 | int([2])<<8 | int([3]),
		PayloadLen:   int(binary.BigEndian.Uint16([4:6])),
		NextHeader:   int([6]),
		HopLimit:     int([7]),
	}
	.Src = make(net.IP, net.IPv6len)
	copy(.Src, [8:24])
	.Dst = make(net.IP, net.IPv6len)
	copy(.Dst, [24:40])
	return , nil
}