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发信人: gon.bbs@bbs.cqupt.edu.cn (人浮于世), 信区: Linux
标 题: 贴一个通过arp广播抢ip的程序
发信站: 幽幽黄桷兰 (Fri May 2 19:10:03 2003)
转信站: SZU!news.tiaozhan.com!news.happynet.org!CQUPT
/send an arp broadcast
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <netdb.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if_arp.h>
#include <net/ethernet.h>
#include <string.h>
#include <errno.h>
#define LINELENGTH 32
#define ETH_HW_ADDR_LEN 6
#define IP_ADDR_LEN 4
#define DEV_LEN 10
struct arp_packet
{
u_char targ_hw_addr[ETH_HW_ADDR_LEN];
u_char src_hw_addr[ETH_HW_ADDR_LEN];
u_short frame_type;
u_short hw_type;
u_short prot_type;
u_char hw_addr_size;
u_char prot_addr_size;
u_short op;
u_char sndr_hw_addr[ETH_HW_ADDR_LEN];
u_char sndr_ip_addr[IP_ADDR_LEN];
u_char rcpt_hw_addr[ETH_HW_ADDR_LEN];
u_char rcpt_ip_addr[IP_ADDR_LEN];
u_char padding[18]; //'cos the minimum ether packet length is 60 bytes.
};
struct ifconf ifc;
int GetIfconf();
int send_arp (unsigned char*, unsigned char*, char*);
int main()
{
struct ifreq *ifr;
int sockfd, flags;
void *ptr;
char *pdev;
char dev[DEV_LEN], temp[16];
unsigned char mac[ETH_HW_ADDR_LEN], ip[IP_ADDR_LEN];
if(GetIfconf() == -1)
//Warning: the result between kernel 2.0 and 2.2 is not the same!!!
//In kernel 2.0, it doesn't display the netcard name whose status
//is down.
return -1;
if((sockfd=socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
free(ifc.ifc_buf);
ifc.ifc_req = NULL;
return -1;
}
for(ptr=ifc.ifc_buf; (caddr_t)ptr < ifc.ifc_buf+ifc.ifc_len; ){
ifr=(struct ifreq *)ptr;
//for the next one in buffer
ptr += sizeof(ifr->ifr_name)+sizeof(struct sockaddr);
strncpy(dev, ifr->ifr_name, DEV_LEN-1);
if(strcmp(dev, "lo") == 0) //loopback device
continue;
else if((pdev = strchr(dev, ':')) != NULL)
//virtual device
*pdev = 0;
//get the ip address
if(ioctl(sockfd, SIOCGIFADDR, ifr) == -1) {
free(ifc.ifc_buf);
ifc.ifc_req = NULL;
close(sockfd);
return -1;
}
memcpy(ip, (void *)&((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr
.s_a
dd
r, sizeof(ip));
//get the hardware address
if(ioctl(sockfd, SIOCGIFHWADDR, ifr) == -1) {
free(ifc.ifc_buf);
ifc.ifc_req = NULL;
close(sockfd);
return -1;
}
memcpy(mac, ifr->ifr_hwaddr.sa_data, ETH_HW_ADDR_LEN);
printf("%s ", dev);
inet_ntop(AF_INET, ip, temp, sizeof(temp));
printf("%s ", temp);
printf("%x:%x:%x:%x:%x:%x\n", *mac, *(mac+1), *(mac+2), *(mac+3), *(
mac+
4)
, *(mac+5));
//send arp broadcast
if(send_arp(ip, mac, dev) == -1) {
printf("send arp broadcast fail in dev: %s\n", dev);
} else {
printf("send arp broadcast success in dev: %s\n", dev);
}
} //end for of struct ifreq
free(ifc.ifc_buf);
ifc.ifc_req = NULL;
close(sockfd);
return 0;
}
//get the value of struct ifconf ifc
//global variable: struct ifconf ifc
int GetIfconf()
{
int sockfd;
int len, lastlen;
void *buf;
if((sockfd=socket(AF_INET, SOCK_DGRAM, 0)) == -1)
return -1;
lastlen=0;
len=10*sizeof(struct ifconf);
//size of struct ifconf: 8
//size of struct ifreq: 32
for(;;){
buf=malloc(len);
ifc.ifc_len=len;
ifc.ifc_buf=buf;
if(ioctl(sockfd, SIOCGIFCONF, &ifc) <0) {
free(buf);
return -1;
}
else{
if(ifc.ifc_len == lastlen)
break; //success, the only point to exit for()
lastlen=ifc.ifc_len;
}
len += 10*sizeof(struct ifconf);
free(buf);
}
return 0;
}
//Arp reply to a broadcast MAC address, the target ip address is the same
//with source address. :)
int send_arp (unsigned char *sip, unsigned char *shwa, char *dev)
{
struct arp_packet pkt;
struct sockaddr sa;
int sock;
sock = socket(AF_INET, SOCK_PACKET, htons(ETH_P_ARP));
if (sock < 0) {
printf("create socket error, this program need root privilege.\n");
exit(1);
}
memset(pkt.targ_hw_addr, 0xff, ETH_HW_ADDR_LEN);
memcpy(pkt.src_hw_addr, shwa, ETH_HW_ADDR_LEN);
pkt.frame_type = htons(ETHERTYPE_ARP); //0x0806
pkt.hw_type = htons(ARPHRD_ETHER); //1
pkt.prot_type = htons(ETHERTYPE_IP); //0x0800
pkt.hw_addr_size = ETH_HW_ADDR_LEN; //6
pkt.prot_addr_size = IP_ADDR_LEN; //4
pkt.op = htons(ARPOP_REPLY); //arp reply
memcpy(pkt.sndr_hw_addr, shwa, ETH_HW_ADDR_LEN);
memcpy(pkt.sndr_ip_addr, sip, IP_ADDR_LEN);
memcpy(pkt.rcpt_hw_addr, shwa, ETH_HW_ADDR_LEN);
memcpy(pkt.rcpt_ip_addr, sip, IP_ADDR_LEN);
bzero(pkt.padding,18);
strcpy(sa.sa_data,dev);
if (sendto(sock,&pkt,sizeof(pkt),0,&sa,sizeof(sa)) < 0) {
printf("sendto error\n");
close(sock);
return -1;
}
close(sock);
return 0;
}
The result the program:
eth0 192.168.1.69 0:10:b2:4c:68:a
send arp broadcast success in dev: eth0
//eth0:1 192.168.3.69 is a virtual netcard
eth0 192.168.3.69 0:10:b2:4c:68:a
send arp broadcast success in dev: eth0
eth1 192.168.2.69 0:d0:b7:e0:8f:e1
send arp broadcast success in dev: eth1
The packets captured through: #tcpdump -b arp
15:42:07.789273 eth1 B arp reply 192.168.1.69 is-at 0:10:b2:4c:68:a (0:10:b2
:4c:68:a)
15:42:07.789273 eth1 B arp reply 192.168.3.69 is-at 0:10:b2:4c:68:a (0:10:b2
:4c:68:a)
15:42:07.789273 eth0 B arp reply 192.168.2.69 is-at 0:d0:b7:e0:8f:e1 (0:d0:b
7:e0:8f:e1)
--
※ 来源:·幽幽黄桷兰 bbs.cqupt.edu.cn·[FROM: missyou.net]
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