linux 设置网络API --- 开/关网卡、设置/获取Mac地址

最近在做项目过程中，由于在多线程中使用system函数，有时候出现莫名程序异常终止，最后决定替换所有的system函数，但是对于设置mac地址这个函数试了很多次都没有成功；今天在此总结下原因：

1. 编写的关闭/打开网卡函数没有延时；（一般情况设置开关网卡可能需要初始化，所以如果开关连续可能没有初始化成功，你可以试试在嵌入式Linux命令行下快速的开关网卡，也是没有反应的）

2. 类型转换问题；（由于为了便捷，使用sscanf提取mac字符串，如果使用8bit提取%x,转换出错，最后只能使用32bit，再一个个赋值即可）

#include <stdio.h>#include <stdlib.h>#include <sys/ioctl.h>#include <string.h>#include <sys/types.h>#include <sys/socket.h>#include <net/if.h>#include <netinet/in.h>typedef signed   char   INT8S;typedef unsigned char INT8U;typedef signed   short  INT16S;typedef unsigned short  INT16U;typedef signed  int    INT32S;typedef unsigned int    INT32U;//add by lightd, 2014-06-04//============================================================================//Function:    ifconfig_ethx_down_API //Description: 关闭本地指定网卡 - eg: ifconfig eth0 down//Input:  //Output:  //Return:  //Others:   None//============================================================================INT8S ifconfig_ethx_down_API(const INT8U *interface_name){INT32S  sock_fd;struct ifreq ifr;int selector;  //传入参数合法性检测if(interface_name == NULL){fprintf(stdout, "%s:%d: args invalid!", __FUNCTION__, __LINE__);return -1;}//禁止关闭回环if(strncmp((char *)interface_name, (char *)"lo", 2) == 0)    {       fprintf(stdout, "%s:%d: You can't pull down interface lo!",  __FUNCTION__, __LINE__);       return 0;        }       sock_fd = socket(AF_INET, SOCK_DGRAM, 0);    if(sock_fd < 0)    {        fprintf(stdout, "%s:%d: socket failed!",  __FUNCTION__, __LINE__);        return -2;    }    sprintf(ifr.ifr_name, "%s", interface_name);       if(ioctl(sock_fd, SIOCGIFFLAGS, &ifr) < 0)    {        fprintf(stdout, "%s:%d: ioctl failed 1!",  __FUNCTION__, __LINE__);        return -3;    }selector = IFF_UP;    ifr.ifr_flags &= ~selector;     if(ioctl(sock_fd, SIOCSIFFLAGS, &ifr) < 0)    {        fprintf(stdout, "%s:%d: ioctl failed 2!",  __FUNCTION__, __LINE__);        return -4;    }close( sock_fd );    return 0;}//add by lightd, 2014-06-04//============================================================================//Function:    ifconfig_ethx_up_API //Description: 打开本地指定网卡 - eg: ifconfig eth0 up//Input:  //Output:  //Return:  //Others: None//============================================================================INT8S ifconfig_ethx_up_API(const INT8U *interface_name){INT32S sock_fd;struct ifreq ifr;int selector; //传入参数合法性检测if(interface_name == NULL){fprintf(stdout, "%s:%d: args invalid!",  __FUNCTION__, __LINE__);return -1;}sock_fd = socket(AF_INET, SOCK_DGRAM, 0);if(sock_fd < 0){fprintf(stdout, "%s:%d: create socket failed!",  __FUNCTION__, __LINE__);return -2;}sprintf(ifr.ifr_name, "%s", interface_name);if(ioctl(sock_fd, SIOCGIFFLAGS, &ifr) < 0){fprintf(stdout, "%s:%d: ioctl error 1",  __FUNCTION__, __LINE__);return -3;}selector = (IFF_UP | IFF_RUNNING);ifr.ifr_flags |= selector;  if(ioctl(sock_fd, SIOCSIFFLAGS, &ifr) < 0){fprintf(stdout, "%s:%d: ioctl error 2",  __FUNCTION__, __LINE__);return -4;}close( sock_fd );return 0;}//add by lightd, 2014-06-04//============================================================================//Function:    SetLocalMACAddr_API //Description: 设置本地指定网卡的MAC//Input:  //Output:  //Return:  //Others:   None//Test result: 测试结果 - 连续调用20次不出错//============================================================================INT8S SetLocalMACAddr_API(const INT8U *interface_name, const INT8U *str_macaddr)  {int ret;  int sock_fd;      struct ifreq ifr;      INT32U mac2bit[6];//传入参数合法性检测if(interface_name == NULL || str_macaddr == NULL){fprintf(stdout, "%s:%d: args invalid!",  __FUNCTION__, __LINE__);return -1;}//提取mac格式 sscanf((char *)str_macaddr, "%02X:%02X:%02X:%02X:%02X:%02X", (INT8U *)&mac2bit[0], (INT8U *)&mac2bit[1], (INT8U *)&mac2bit[2], (INT8U *)&mac2bit[3], (INT8U *)&mac2bit[4], (INT8U *)&mac2bit[5]);    sock_fd = socket(PF_INET, SOCK_DGRAM, 0);      if (sock_fd < 0)      {  perror("socket error");            return -2;      }  //设置mac前，必须关闭对应的网卡 - 否则出错    ret = ifconfig_ethx_down_API( interface_name );if(ret < 0){fprintf(stdout, "%s:%d: close eth0 error",  __FUNCTION__, __LINE__);return -3;}sleep(1); //等待网卡关闭OK    sprintf(ifr.ifr_ifrn.ifrn_name, "%s", interface_name);      ifr.ifr_ifru.ifru_hwaddr.sa_family = 1;  ifr.ifr_ifru.ifru_hwaddr.sa_data[0] = mac2bit[0];ifr.ifr_ifru.ifru_hwaddr.sa_data[1] = mac2bit[1];ifr.ifr_ifru.ifru_hwaddr.sa_data[2] = mac2bit[2];ifr.ifr_ifru.ifru_hwaddr.sa_data[3] = mac2bit[3];ifr.ifr_ifru.ifru_hwaddr.sa_data[4] = mac2bit[4];ifr.ifr_ifru.ifru_hwaddr.sa_data[5] = mac2bit[5];    ret = ioctl(sock_fd, SIOCSIFHWADDR, &ifr);      if (ret != 0)      {  perror("set mac address erorr");        return -4;      }  close( sock_fd );    ret = ifconfig_ethx_up_API( interface_name );if(ret < 0){fprintf(stdout, "%s:%d: open eth0 error!",  __FUNCTION__, __LINE__);return -5;}sleep(2); //等待网卡打开OK    return 0;  }//add by lightd, 2014-06-04//============================================================================//Function:    GetLocalMACAddr_API //Description: 获取本地指定网卡的MAC//Input:  //Output:  //Return:  //Others:   None//============================================================================INT8S GetLocalMACAddr_API(const INT8U *interface_name, INT8U *str_macaddr)  {      INT32S  sock_fd;      struct ifreq ifr_mac;  //传入参数合法性检测if(interface_name == NULL || str_macaddr == NULL){fprintf(stdout, "%s:%d: args invalid!",  __FUNCTION__, __LINE__);return -1;}    sock_fd = socket( AF_INET, SOCK_STREAM, 0 );      if( sock_fd == -1)      {          perror("create socket failed");  sprintf((char *)str_macaddr, "00:00:00:00:00:00");        return -2;      }        //指定网卡    memset(&ifr_mac, 0, sizeof(ifr_mac));         sprintf(ifr_mac.ifr_name, "%s", interface_name);       //获取指定网卡的mac地址    if( (ioctl( sock_fd, SIOCGIFHWADDR, &ifr_mac)) < 0 )     {          perror("mac ioctl error");  sprintf((char *)str_macaddr, "00:00:00:00:00:00");        return -3;      }        close( sock_fd );      sprintf((char *)str_macaddr,"%02x:%02x:%02x:%02x:%02x:%02x",              (unsigned char)ifr_mac.ifr_hwaddr.sa_data[0],              (unsigned char)ifr_mac.ifr_hwaddr.sa_data[1],              (unsigned char)ifr_mac.ifr_hwaddr.sa_data[2],              (unsigned char)ifr_mac.ifr_hwaddr.sa_data[3],              (unsigned char)ifr_mac.ifr_hwaddr.sa_data[4],              (unsigned char)ifr_mac.ifr_hwaddr.sa_data[5]);        printf("local mac:<%s> \n", str_macaddr);              return 0;}int main(void){INT8U str_macaddr[20];memset(str_macaddr, 0, sizeof(str_macaddr));GetLocalMACAddr_API("eth0", str_macaddr);fprintf(stdout, "1 mac: %s\n", str_macaddr);//ifconfig_ethx_down_API("eth0");//system("ifconfig eth0 down");//usleep(500000);//system("ifconfig eth0 up");//usleep(500000);//sleep(1); //10ms//ifconfig_ethx_down_API("eth0");//sleep(1);SetLocalMACAddr_API("eth0", "08:00:11:22:33:44");//ifconfig_ethx_up_API("eth0");//ifconfig_ethx_up_API("eth0");//sleep(2); memset(str_macaddr, 0, sizeof(str_macaddr));GetLocalMACAddr_API("eth0", str_macaddr);fprintf(stdout, "2 mac: %s\n", str_macaddr);system("ping 200.200.200.100");//usleep(50000); //ifconfig_ethx_down_API("eth0");//ifconfig_ethx_up_API("eth0");//memset(str_macaddr, 0, sizeof(str_macaddr));//GetLocalMACAddr_API("eth0", str_macaddr);fprintf(stdout, "2 mac: %s\n", str_macaddr);return 0;}