linux 下获取当前网络连接状态的两种方法
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#include
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#include
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#include
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#include
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#include
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#include
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#include
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#include
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#define ETHTOOL_GLINK 0x0000000a /* Get link status (ethtool_value) */
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typedef
enum { IFSTATUS_UP, IFSTATUS_DOWN, IFSTATUS_ERR }
interface_status_t;
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typedef
signed
int u32;
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/* for passing single values */
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struct ethtool_value
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{
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u32 cmd;
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u32 data;
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};
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interface_status_t interface_detect_beat_ethtool(
int fd,
char *iface)
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{
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struct ifreq ifr;
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struct ethtool_value edata;
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memset(&ifr,
0,
sizeof(ifr));
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strncpy(ifr.ifr_name, iface,
sizeof(ifr.ifr_name)
-1);
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edata.cmd = ETHTOOL_GLINK;
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ifr.ifr_data = (
caddr_t) &edata;
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if (ioctl(fd, SIOCETHTOOL, &ifr) ==
-1)
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{
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perror(
"ETHTOOL_GLINK failed ");
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return IFSTATUS_ERR;
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}
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return edata.data ? IFSTATUS_UP : IFSTATUS_DOWN;
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}
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int main (int argc, char *argv[])
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{
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FILE *fp;
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interface_status_t status;
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char buf[
512] = {
'\0'};
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char hw_name[
10] = {
'\0'};
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char *token =
NULL;
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/* 获取网卡名称 */
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if ((fp = fopen(
"/proc/net/dev",
"r")) !=
NULL)
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{
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while (fgets(buf,
sizeof(buf), fp) !=
NULL)
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{
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if(
strstr(buf,
"eth") !=
NULL)
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{
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token = strtok(buf,
":");
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while (*token ==
' ') ++token;
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strncpy(hw_name, token,
strlen(token));
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}
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}
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}
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fclose(fp);
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//方法一：查看一个文件文件，相对来说比较简单
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#if 1
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char carrier_path[
512] = {
'\0'};
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memset(buf,
0,
sizeof(buf));
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snprintf(carrier_path,
sizeof(carrier_path),
"/sys/class/net/%s/carrier", hw_name);
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if ((fp = fopen(carrier_path,
"r")) !=
NULL)
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{
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while (fgets(buf,
sizeof(buf), fp) !=
NULL)
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{
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if (buf[
0] ==
'0')
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{
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status = IFSTATUS_DOWN;
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}
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else
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{
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status = IFSTATUS_UP;
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}
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}
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}
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else
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{
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perror(
"Open carrier ");
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}
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fclose(fp);
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#endif
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//方法二：用函数吧！有点复杂，但是也是一种有效的办法
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#if 1
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int fd;
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if((fd = socket(AF_INET, SOCK_STREAM,
0)) ==
-1)
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{
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perror(
"socket ");
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exit(
0);
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}
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status = interface_detect_beat_ethtool(fd, hw_name);
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close(fd);
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#endif
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switch (status)
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{
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case IFSTATUS_UP:
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printf(
"%s : link up\n", hw_name);
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break;
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case IFSTATUS_DOWN:
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printf(
"%s : link down\n", hw_name);
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break;
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default:
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printf(
"Detect Error\n");
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break;
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}
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return
0;
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}