send_arp.c

这是linux下关于C的编程

/*
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. [e-mail] 
运行方法./send_arp my_ip my_eth_addr network_ip broadcast_eth_addr
如本机ip为192.168.0.1,eth_addr 为 10：24：26：97：00：21
则运行 ./send_arp 192.168.0.1   10：24：26：97：00：21 192.168.0.255 ff:ff:ff:ff:ff:ff
*/ 
#include <netdb.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <signal.h>
#include <netinet/ip.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>
#include <netinet/ip_icmp.h>
#include <linux/if_ether.h>
#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<number;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++; 
} 
}