#include?
#include?
#include?
#include?
#include?
#define?DataSize?5000
#define?MTU?60
using?namespace?std;

//?IP頭部結(jié)構(gòu)
typedef?struct?header
{
????unsigned?char?VIHL;????????????????????????????//?Version?and?IHL
????unsigned?char?ToS;?????????????????????????????//?Type?of?Service
????unsigned?short?TotalLen;???????????????????????//?Total?Length
????unsigned?short?ID;?????????????????????????????//?Identfication
????unsigned?short?FlagOff;????????????????????????//?Flags?and?Fragment?Offset
????unsigned?char?TTL;?????????????????????????????//?Time?to?Live
????unsigned?char?Protocol;????????????????????????//?Protocol
????unsigned?short?Checksum;???????????????????????//?Checksum
????unsigned?long?SrcAddr;?????????????????????????//?Source?Address
????unsigned?long?DstAddr;?????????????????????????//?Destination?Address
char?*Data;????????????????????????????????????????//?data
}IPHeader*pIPHeader;

//?重組資源結(jié)構(gòu)
typedef?struct?buf
{
????????char?*Data;????????????????????????????????//?數(shù)據(jù)緩沖
????????IPHeader?ipHeader;?????????????????????????//?頭部緩沖
????????unsigned?char?*RCVBT;??????????????????????//?分片塊位表
????????unsigned?int?TDL;??????????????????????????//?總數(shù)據(jù)長度頭部
????????unsigned?short?TIMER;??????????????????????//?定時(shí)器
????????unsigned?int?BUFID;????????????????????????//?BUFID
}BUFFER?*pBUFFER;

/*****************************************************************
函數(shù)聲明
*****************************************************************/
short?CheckSum（IPHeader?ipHeader）;?????????????????//?校驗(yàn)和計(jì)算函數(shù)
void?bit_set（void?*buf?int?offset）;???????????????//?置1函數(shù)
int?bit_isset（void?*buf?int?offset）;??????????????//?置1判斷函數(shù)
void?Fragment（IPHeader?ipHeader）;??????????????????//?分片函數(shù)
void?Reassembly（IPHeader?ipHeader）;????????????????//?重組函數(shù)
void?read（）;???????????????????????????????????????//?讀取分片函數(shù)

/*****************************************************************
函數(shù)名：CheckSum
描述：校驗(yàn)和計(jì)算
參數(shù)：IPHeader?ipHeader
return：unsigned?short?checkSum
*****************************************************************/
short?CheckSum（IPHeader?ipHeader）????
{
????????unsigned?short?checkSum;
????????int?sum;

????????sum?=?（（ipHeader.VIHL<<8）+ipHeader.ToS）?
????????????????+ipHeader.TotalLen?
????????????????+?ipHeader.ID?
????????????????+?ipHeader.FlagOff?
????????????????+?（（ipHeader.TTL<<8）+ipHeader.Protocol）
????????????????+?（ipHeader.SrcAddr>>16）?
????????????????+（ipHeader.SrcAddr&65535）?
????????????????+（ipHeader.DstAddr>>16）?
????????????????+?（ipHeader.DstAddr&65535）;
????????while?（sum>65535）
????????{
????????????????sum?=?（sum>>16）?+?（sum&65535）;
????????}
????????checkSum?=?（unsigned?short）~sum;
????????return?checkSum;
}

/*****************************************************************
函數(shù)名：bit_set
描述：位置1函數(shù)
參數(shù)：void?*buf?int?offset
return：NULL
*****************************************************************/
void?bit_set（void?

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2012-10-18?10:14??分片\
?????文件???????14630??2012-10-16?17:18??分片\fragment.cpp