[C++]VC自定义发IP包例子-优快云博客

本文介绍了一个自定义TCP/IP包发送的例子，通过构造IP头部和TCP头部来实现向指定目标发送SYN请求的功能。该示例展示了如何设置源IP、目标IP及端口等参数，并使用校验和函数确保数据包的正确性。
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/************************************
*自定义发IP包例子(TCP/IP包发送)
*给目标主机的端口发送一个 syn请求,
*注意目标主机的信息会发给发送IP地址的主机
*这说明TCP/IP协议本身有IP期骗的漏洞
*这种方运可以自己写成特殊的基于IP协议上层的自定义协议
************************************/
 
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netinet/ip.h>   //ip
#include <netinet/tcp.h> //tcp
#include <stdlib.h>
 
//发送端IP

char srcip[]="100.100.100.100";
//目标端IP

char dstip[]="192.168.11.220";
//发送端IP端口

int srcport=25;
//目标IP端口

int dstport=99;
 
//以下是从ip.h和tcp.h取的,但BSD和LINUX用的名称有些不一样主要是TCP不一样
 
typedef struct _IP
{
#if __BYTE_ORDER == __LITTLE_ENDIAN

    unsigned int ip_hl:4;               //little-endian IP头长度(单位为32位)4位

    unsigned int ip_v:4;                //版本号4 IP4用4
#endif
#if __BYTE_ORDER == __BIG_ENDIAN

    unsigned int ip_v:4;                // version

    unsigned int ip_hl:4;               // header length
#endif

    u_int8_t ip_tos;                    //服务类型  一般为0

    u_short ip_len;                     //数据总长度 (单位为32位)

    u_short ip_id;                      //标识16

    u_short ip_off;                     //分段偏移
#define IP_RF 0x8000                    // reserved fragment flag  //标志
#define IP_DF 0x4000                    // dont fragment flag
#define IP_MF 0x2000                    // more fragments flag
#define IP_OFFMASK 0x1fff               // mask for fragmenting bits

    u_int8_t ip_ttl;                    //生存时间

    u_int8_t ip_p;                      //传输协议 tcp是6

    u_short ip_sum;                     //头校验和

    struct in_addr ip_src, ip_dst;      // 源地址 目标地址
}IP;
 
typedef struct _TCPHeader
{

    u_int16_t source;               // 源端口

    u_int16_t dest;                 // 目的端口

    tcp_seq seq;                    // 序号

    tcp_seq ack_seq;                // 确认号 收到的TCP信息的序号+1
#if __BYTE_ORDER == __LITTLE_ENDIAN

    u_int16_t res1:4;               //保留

    u_int16_t doff:4;               //保留

    u_int16_t fin:1;                //标志 结束

    u_int16_t syn:1;                //标志 同步

    u_int16_t rst:1;                //标志 重置

    u_int16_t psh:1;                //标志 入栈

    u_int16_t ack:1;                //标志 确认

    u_int16_t urg:1;                //标志 紧急

    u_int16_t res2:2;
#elif __BYTE_ORDER == __BIG_ENDIAN

    u_int16_t doff:4;

    u_int16_t res1:4;

    u_int16_t res2:2;

    u_int16_t urg:1;

    u_int16_t ack:1;

    u_int16_t psh:1;

    u_int16_t rst:1;

    u_int16_t syn:1;

    u_int16_t fin:1;
#else
#error  "Adjust your <bits/endian.h> defines"
#endif

    u_int16_t window;           //窗口

    u_int16_t check;            //校验和

    u_int16_t urg_ptr;          //紧急指针
}TCPHeader;
 
//校验和函数 ip头

unsigned short IPCheakSum (unsigned short *packet, int packlen) 
{

    register unsigned long sum = 0;

    while (packlen > 1) {

        sum+= *(packet++);

        packlen-=2;

    }

    if (packlen > 0)

        sum += *(unsigned char *)packet;

    while (sum >> 16)

        sum = (sum & 0xffff) + (sum >> 16);
 
    return (unsigned short) ~sum;
}
//校验和函数 tcp头

unsigned short TCPCheckSum (unsigned char *iphdr, unsigned short *packet,int packlen) 
{

    unsigned short *buf;

    unsigned short res;

    buf = malloc(packlen+12);

    if(buf == NULL) return 0;

    memcpy(buf,iphdr+12,8); //源IP地址和目标IP地址

    *(buf+4)=htons((unsigned short)(*(iphdr+9)));

    *(buf+5)=htons((unsigned short)packlen);

    memcpy(buf+6,packet,packlen);

    res = IPCheakSum(buf,packlen+12);

    free(buf);

    return res;
}
 
int main()
{

    int sock, bytes_send, fromlen,n,id,s;

    unsigned char buffer[65535];

    sockaddr_in toaddr;

    IP *ip;

    TCPHeader *tcp;

    for (n=0;n<60000;n++ )

    {

        buffer[n]=0;

    }

    //发送地址

    toaddr.sin_family =AF_INET;

    //        inet_aton("192.168.11.38",&toaddr.sin_addr);   //字符串转入地址

    inet_aton(dstip,&toaddr.sin_addr);   //字符串转入地址

    //建立原始TCP包方式IP+TCP信息包

    sock = socket(AF_INET, SOCK_RAW,IPPROTO_RAW);   //IP方式

    //     sock = socket(AF_INET, SOCK_RAW, IPPROTO_TCP);

    if (sock>0) {printf("socket ok\n");}

    else {printf ("socket error \n");}

    n=1;

    if (setsockopt(sock, IPPROTO_IP, IP_HDRINCL, &n, sizeof(n)) < 0) {

        printf("2");

        perror("IP_HDRINCL");

        exit(1);

    }

    ip=(struct ip *)buffer;

    ip->ip_id=0x9911;               

    ip->ip_v=4;

    ip->ip_hl=5;                           

    ip->ip_ttl=36;                         

    ip->ip_p=6;     //tcp 为6

    ip->ip_len=htons(60);

    inet_aton(dstip,&ip->ip_dst);

    //        inet_aton("192.168.11.38",&ip->ip_dst);

    tcp = (struct tcphdr *)(buffer + (4*ip->ip_hl));

    tcp->source=htons(srcport);                            //源端口

    tcp->dest=htons(dstport);  

    tcp->seq=htons(0x9990);

    tcp->doff=0x15;

    tcp->ack_seq=0;

    tcp->syn=1;

    tcp->window=htons(0x20);

    inet_aton(srcip,&ip->ip_src);
 
    //        ip->ip_src.s_addr=htonl(0x09010101+n);

    tcp->check=0x0;       

    tcp->check=TCPCheckSum((unsigned char *)buffer, (unsigned short *)tcp,40);

    ip->ip_sum=0;

    ip->ip_sum=IPCheakSum((unsigned short *)buffer,20);

    bytes_send=sendto(sock,buffer,60,0,(struct sockaddr *)&toaddr,sizeof(toaddr));    
 
    if (bytes_send>0)

    {

        printf("OK bytes_send %d \n",bytes_send);

        printf("IP_source address ::: %s \n",inet_ntoa(ip->ip_src));

        printf("IP_dest address ::: %s \n",inet_ntoa(ip->ip_dst));

    }
}