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			56 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
		
		
			
		
	
	
			56 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
|  | // 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 ( | ||
|  | 	"encoding/binary" | ||
|  | 	"fmt" | ||
|  | 	"net" | ||
|  | ) | ||
|  | 
 | ||
|  | 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 (h *Header) String() string { | ||
|  | 	if h == nil { | ||
|  | 		return "<nil>" | ||
|  | 	} | ||
|  | 	return fmt.Sprintf("ver=%d tclass=%#x flowlbl=%#x payloadlen=%d nxthdr=%d hoplim=%d src=%v dst=%v", h.Version, h.TrafficClass, h.FlowLabel, h.PayloadLen, h.NextHeader, h.HopLimit, h.Src, h.Dst) | ||
|  | } | ||
|  | 
 | ||
|  | // ParseHeader parses b as an IPv6 base header. | ||
|  | func ParseHeader(b []byte) (*Header, error) { | ||
|  | 	if len(b) < HeaderLen { | ||
|  | 		return nil, errHeaderTooShort | ||
|  | 	} | ||
|  | 	h := &Header{ | ||
|  | 		Version:      int(b[0]) >> 4, | ||
|  | 		TrafficClass: int(b[0]&0x0f)<<4 | int(b[1])>>4, | ||
|  | 		FlowLabel:    int(b[1]&0x0f)<<16 | int(b[2])<<8 | int(b[3]), | ||
|  | 		PayloadLen:   int(binary.BigEndian.Uint16(b[4:6])), | ||
|  | 		NextHeader:   int(b[6]), | ||
|  | 		HopLimit:     int(b[7]), | ||
|  | 	} | ||
|  | 	h.Src = make(net.IP, net.IPv6len) | ||
|  | 	copy(h.Src, b[8:24]) | ||
|  | 	h.Dst = make(net.IP, net.IPv6len) | ||
|  | 	copy(h.Dst, b[24:40]) | ||
|  | 	return h, nil | ||
|  | } |