通过IP或socket获取对方的MAC地址

 1。通过已经连接的socket文件获取：

  int getpeermac( int sockfd, char *buf ){int ret =0;struct arpreq arpreq;struct sockaddr_in dstadd_in; socklen_t len = 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;} 

 

2。 通过IP获取：

int getpeermac_by_ip(char *ipaddr, char* buf){int sockfd;unsigned char *ptr;struct arpreq arpreq;struct sockaddr_in *sin;struct sockaddr_storage ss;char addr[INET_ADDRSTRLEN+1];memset(addr, 0, INET_ADDRSTRLEN+1);memset(&ss, 0, sizeof(ss));if (argc != 2) {printf("USAGE arpg ip_addr/n");return -1;}sockfd = socket(AF_INET, SOCK_DGRAM, 0);if (sockfd == -1) {perror("socket error");return -1;}sin = (struct sockaddr_in *) &ss;sin->sin_family = AF_INET;if (inet_pton(AF_INET, argv[1], &(sin->sin_addr)) <= 0) {perror("inet_pton error");return -1;}sin = (struct sockaddr_in *) &arpreq.arp_pa;memcpy(sin, &ss, sizeof(struct sockaddr_in));strcpy(arpreq.arp_dev, "eth1");arpreq.arp_ha.sa_family = AF_UNSPEC;if (ioctl(sockfd, SIOCGARP, &arpreq) < 0) {perror("ioctl SIOCGARP: ");return -1;}ptr = (unsigned char *)arpreq.arp_ha.sa_data;sprintf(buf,"%x:%x:%x:%x:%x:%x", *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5));return 0;}