发现一个有意思的东西【通过IP或sock取对方mac】。
/**
* @send_arp.c
* @This software is intended to be used as a example to show how to send and receive arp request with Linux * PF_PACKET interface
* @Author：xuelei
**/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include /* 需要里面的 glibc 版本号 */
#if __GLIBC__ >= 2 && __GLIBC_MINOR >= 1
#include
#include /* 链路层（L2）协议 */
#else
#include
#include
#include /* 链路层协议 */
#endif
#include
#define INLEN 4
#define MAC_BCAST_ADDR(uint8_t *) "\xff\xff\xff\xff\xff\xff"
void usage_quit(char *arg0);
int get_ifi(char *dev, char *mac, int macln, struct in_addr *lc_addr, int ipln);
void prmac(u_char *ptr);
int main(int argc, char **argv)
{
if(argc != 2)
usage_quit(argv);
int fd, salen, n;
u_char *mac;
char recv_buf, rep_addr;
struct in_addr lc_addr, req_addr;
struct sockaddr_ll reqsa, repsa;
struct arp_pkt {
struct ether_header eh;
struct ether_arp ea;
u_char padding;
} req;
bzero(&reqsa, sizeof(reqsa));
reqsa.sll_family = PF_PACKET;
reqsa.sll_ifindex = if_nametoindex("eth0");
if((fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ARP))) < 0) {
perror("Socket error");
exit(1);
}
mac = (char *)malloc(ETH_ALEN);
bzero(&req, sizeof(req));
if(get_ifi("eth0", mac, ETH_ALEN, &lc_addr, INLEN)) {
fprintf(stderr, "Error: Get host’s information failed\n");
exit(0);
}
printf(" Host MAC is: %02x:%02x:%02x:%02x:%02x:%02x\n",*mac,*(mac+1),*(mac+2),*(mac+3),*(mac+4),*(mac+5));
printf(" Host IP is: %s\n", inet_ntop(AF_INET, &lc_addr, rep_addr, 1024));
/* 填写以太网头部*/
memcpy(req.eh.ether_dhost, MAC_BCAST_ADDR, ETH_ALEN);
memcpy(req.eh.ether_shost, mac, ETH_ALEN);
req.eh.ether_type = htons(ETHERTYPE_ARP);
/* 填写arp数据 */
req.ea.arp_hrd = htons(ARPHRD_ETHER);
req.ea.arp_pro = htons(ETHERTYPE_IP);
req.ea.arp_hln = ETH_ALEN;
req.ea.arp_pln = INLEN;
req.ea.arp_op = htons(ARPOP_REQUEST);
memcpy(req.ea.arp_sha, mac, ETH_ALEN);
memcpy(req.ea.arp_spa, &lc_addr, INLEN);
inet_aton(argv, req.ea.arp_tpa);
bzero(recv_buf, sizeof(recv_buf));
bzero(&repsa, sizeof(repsa));
salen = sizeof(struct sockaddr_ll);
if((n = sendto(fd, &req, sizeof(req), 0, (struct sockaddr *)&reqsa, sizeof(reqsa))) <= 0) {
perror("Sendto error");
exit(1);
}
printf("Broadcast arp request of %s, %d bytes be sent\n\n", argv, n);
while(1) {
if((n = recvfrom(fd, recv_buf, sizeof(req), 0, (struct sockaddr *)&repsa, &salen)) <= 0) {
perror("Recvfrom error");
exit(1);
}
if(ntohs(*(__be16 *)(recv_buf + 20))==2 && !memcmp(req.ea.arp_tpa, recv_buf + 28, 4)) {
printf("Response from %s, %d bytes received\n", argv, n);
printf(" Peer IP is: %s\n", inet_ntop(AF_INET, (struct in_addr *)(recv_buf + 28), rep_addr, 1024));
prmac( (u_char *)(recv_buf + 22) ); //prmac( (u_char *)(recv_buf + 6) );
break;
}
else
{
printf("Have recive data\n");
break;
}
}
free(mac);
}
int get_ifi(char *dev, char * mac, int macln, struct in_addr *lc_addr, int ipln)
{
int reqfd, n;
struct ifreq macreq;
reqfd = socket(AF_INET, SOCK_DGRAM, 0);
strcpy(macreq.ifr_name, dev);
/* 获取本地接口MAC地址*/
if(ioctl(reqfd, SIOCGIFHWADDR, ¯eq) != 0)
return 1;
memcpy(mac, macreq.ifr_hwaddr.sa_data, macln);
/* 获取本地接口IP地址*/
if(ioctl(reqfd, SIOCGIFADDR, ¯eq) != 0)
return 1;
memcpy(lc_addr, &((struct sockaddr_in *)(¯eq.ifr_addr))->sin_addr, ipln);
return 0;
}
void prmac(u_char *ptr)
{
printf(" Peer MAC is: %02x:%02x:%02x:%02x:%02x:%02x\n",*ptr,*(ptr+1),*(ptr+2),*(ptr+3),*(ptr+4),*(ptr+5));
}
void usage_quit(char *arg0)
{
fprintf(stderr, "Usage: %s \n", arg0);
exit(1);
}
int getpeermac( int sockfd, char *buf )
{
int ret =0;
struct arpreq arpreq;
struct sockaddr_in dstadd_in;
socklen_tlen = sizeof( struct sockaddr_in );
memset( &arpreq, 0, sizeof( struct arpreq ));
memset( &dstadd_in, 0, sizeof( struct sockaddr_in ));
if( getpeername( sockfd, (struct sockaddr*)&dstadd_in, &len ) < 0 )
err_err("getpeername()");
else
{
memcpy( &arpreq.arp_pa, &dstadd_in, sizeof( struct sockaddr_in ));
strcpy(arpreq.arp_dev, "eth1");
arpreq.arp_pa.sa_family = AF_INET;
arpreq.arp_ha.sa_family = AF_UNSPEC;
if( ioctl( sockfd, SIOCGARP, &arpreq ) < 0 )
err_err("ioctl SIOCGARP");
else
{
unsigned char* ptr = (unsigned char *)arpreq.arp_ha.sa_data;
ret = sprintf(buf, "%02x%02x%02x%02x%02x%02x", *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5));
}
}
return ret;
}
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