linux 設定網路API --- 開/關網絡卡、設定/獲取Mac地址
阿新 • • 發佈：2019-02-03
最近在做專案過程中，由於在多執行緒中使用system函式，有時候出現莫名程式異常終止，最後決定替換所有的system函式，但是對於設定mac地址這個函式試了很多次都沒有成功；今天在此總結下原因：
1. 編寫的關閉/開啟網絡卡函式沒有延時；（一般情況設定開關網絡卡可能需要初始化，所以如果開關連續可能沒有初始化成功，你可以試試在嵌入式Linux命令列下快速的開關網絡卡，也是沒有反應的）
2. 型別轉換問題；（由於為了便捷，使用sscanf提取mac字串，如果使用8bit提取%x,轉換出錯，最後只能使用32bit，再一個個賦值即可）
#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: 關閉本地指定網絡卡 - 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; //傳入引數合法性檢測 if(interface_name == NULL) { fprintf(stdout, "%s:%d: args invalid!", __FUNCTION__, __LINE__); return -1; } //禁止關閉迴環 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: 開啟本地指定網絡卡 - 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; //傳入引數合法性檢測 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: 設定本地指定網絡卡的MAC //Input: //Output: //Return: //Others: None //Test result: 測試結果 - 連續呼叫20次不出錯 //============================================================================ INT8S SetLocalMACAddr_API(const INT8U *interface_name, const INT8U *str_macaddr) { int ret; int sock_fd; struct ifreq ifr; INT32U mac2bit[6]; //傳入引數合法性檢測 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; } //設定mac前，必須關閉對應的網絡卡 - 否則出錯 ret = ifconfig_ethx_down_API( interface_name ); if(ret < 0) { fprintf(stdout, "%s:%d: close eth0 error", __FUNCTION__, __LINE__); return -3; } sleep(1); //等待網絡卡關閉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); //等待網絡卡開啟OK return 0; } //add by lightd, 2014-06-04 //============================================================================ //Function: GetLocalMACAddr_API //Description: 獲取本地指定網絡卡的MAC //Input: //Output: //Return: //Others: None //============================================================================ INT8S GetLocalMACAddr_API(const INT8U *interface_name, INT8U *str_macaddr) { INT32S sock_fd; struct ifreq ifr_mac; //傳入引數合法性檢測 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; } //指定網絡卡 memset(&ifr_mac, 0, sizeof(ifr_mac)); sprintf(ifr_mac.ifr_name, "%s", interface_name); //獲取指定網絡卡的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; }