IP头结构&其他解析
Version???? 4????? IP頭的版本號,目前是IPv4,最新是IPv6
Header Length???? 4????? IP頭的長度,若沒有特殊選擇,IP頭總是20字節長
Type of Service???? 8????? 服務類型,定義了數據傳輸的優先級、延遲、吞吐量和可靠性等特性
Total Packet Length???? 16????? IP包的長度,若沒有特殊選項,一般為20字節長
Identification???? 16????? IP包標識,主機使用它唯一確定每個發送的數據報
Flag???? 3????? IP數據分割標志
Fragment Offset???? 13????? IP數據分割偏移
Time to Live????? 8????? 數據報在網絡上的存活時間,每通過一個路由器,該數值減一
Protocol????? 8????? TCP/IP協議類型,比如:ICMP為1,IGMP為2,TCP為6,UDP為17等
Header Checksum???? 16???? 頭部檢驗和
Source IP Address????? 32???? 源IP地址
Destination IP Address???? 32????? 目的IP地址
Other?????? 其他選項
Data????? ??數據
struct iphdr
???? {
?????? unsigned char ihl:4, version:4, tos;
?????? unsigned short tot_len, id, frag_off;
?????? unsigned char ttl, protocol;
?????? unsigned short check;
?????? unsigned int saddr, daddr;
???? };
????
???? struct igmphdr
???? {
?????? unsigned char type, code;
?????? unsigned short cksum;
?????? struct in_addr group;
???? };
typedef struct ethdr
{
???? unsigned char?? eh_dst[6];
???? unsigned char?? eh_src[6];
???? unsigned short eh_type;
}
struct udphdr
{
???? unsigned short souceport;
???? unsigned short destport;
???? unsigned short length;
???? unsigned short checksum;
}
struct tcphdr { unsigned short source;
??????? unsigned short dest;
??????? unsigned long seq;
??????? unsigned long ack_seq;???????
??????? unsigned short doff:4;
??????? unsigned char flags;
??????? unsigned short window;???????
??????? unsigned short check;
??????? unsigned short urg_ptr;
};
轉載于:https://www.cnblogs.com/voswin/articles/1271774.html
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