通過arp實現輸入ip地址輸出mac地址

           當一台手機連上wifi熱點時，想通過ip知道對方的mac地址，之前網路上找了篇通過netbios實現通過ip尋找mac地址，然而該方法只局限於windows系統，後來瞭解到通過arp協議可以實現這個功能。於是就有如下的代碼：

ipmac.c：

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <netdb.h>#include <sys/stat.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <net/if.h> #include <netinet/if_ether.h> #include <sys/ioctl.h>#include <net/if_arp.h>struct arpreq arpreq; int main(int argc, char* argv[]){        if(argc < 2)        {                printf("Usage: %s IP\n",argv[0]);                return 0;        }  int sd;  struct arpreq arpreq;  struct sockaddr_in *sin;  struct in_addr ina;  unsigned char *hw_addr;  sd = socket(AF_INET, SOCK_DGRAM, 0);  if (sd < 0)  {      perror("socket() error\n");      exit(1);  }  printf("IP : %s\n", argv[1]);  memset(&arpreq, 0, sizeof(struct arpreq));  sin = (struct sockaddr_in *) &arpreq.arp_pa;  memset(sin, 0, sizeof(struct sockaddr_in));  sin->sin_family = AF_INET;  ina.s_addr = inet_addr(argv[1]);  memcpy(&sin->sin_addr, (char *)&ina, sizeof(struct in_addr));  strcpy(arpreq.arp_dev, "wl0.1"); //wifi熱點所用的網卡為wl0.1  ioctl(sd, SIOCGARP, &arpreq);     printf("\nentry has been successfully retreived\n");  hw_addr = (unsigned char *) arpreq.arp_ha.sa_data;  printf("MAC: %x:%x:%x:%x:%x:%x\n",    hw_addr[0], hw_addr[1], hw_addr[2], hw_addr[3], hw_addr[4], hw_addr[5]);  return 0;} 

Android.mk：

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_ARM_MODE := armLOCAL_SRC_FILES := \        ipmac.cLOCAL_MODULE:= ipmacLOCAL_PRELINK_MODULE := falseLOCAL_C_INCLUDES += \        $(LOCAL_PATH)/includeinclude $(BUILD_EXECUTABLE) //編譯成可執行檔

編譯後執行該./ipmac xxx .xxx.xxx.xxx（ip） 即可列印出該ip的mac地址。