用C/C++实现linux下检测网络接口状态

#include <sys/types.h>
#include <string.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <errno.h>
#include <net/if.h>
 
struct ethtool_value 
{
 __uint32_t cmd;
 __uint32_t data;
};
 
/*return 1:has cable; return 0:no cable*/
int detect_eth_cable(char *ifname) 
{
 struct ethtool_value edata;
 struct ifreq ifr;
 int fd = -1, err = 0;
 
 memset(&ifr, 0, sizeof(ifr));
 strcpy(ifr.ifr_name, ifname);
 
 fd = socket(AF_INET, SOCK_DGRAM, 0);
 if (fd < 0) {
  //perror("Cannot get control socket");
  return -1;
  }
 edata.cmd = 0x0000000A;
 ifr.ifr_data = (caddr_t)&edata;
 err = ioctl(fd, 0x8946, &ifr);
 if (err == 0) {
  fprintf(stdout, "Link detected: %s\n", edata.data ? "yes":"no");
 } else if (errno != EOPNOTSUPP) {
  perror("Cannot get link status");
  }
 return(edata.data==1 ? 1:0);
}
int main(int argc, char**argv)
{
 detect_eth_cable("p1p1");
 return 0;
}

int get_netportstatus(const char *interface) {
 char cmd[1024];
 char *tt;
 FILE *fp;
 int devflag;
 devflag=get_netflag(interface);
 if (devflag==DEV_DOWN) {
 sprintf(cmd,"ifconfig %s up",interface);
 system(cmd);
 }
 sprintf(cmd,"ethtool %s | grep \"Link detected\" > /tmp/eth.temp",interface);
 system(cmd);
 if (devflag==DEV_DOWN) {
 sprintf(cmd,"ifconfig %s down",interface);
 system(cmd);
 }
 fp=fopen("/tmp/eth.temp","r");
 if (fp==NULL) {
 system("rm -rf /tmp/eth.temp");
 return -1;
 }
 fgets(cmd,1024,fp);
 fclose(fp);
 system("rm -rf /tmp/eth.temp");
 tt=strstr(cmd,"no");
 if (tt!=NULL) return LINK_DOWN;
 tt=strstr(cmd,"yes");
 if (tt!=NULL) return LINK_UP;
 return -1;
}

#include <sys/types.h>
#include <string.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <errno.h>
#include <net/if.h>
 
 
struct ethtool_value {
  __uint32_t  cmd;
  __uint32_t  data;
};
 
 
int main(int , char* [])
{
 struct ethtool_value edata;
 int fd = -1, err = 0;
 struct ifreq ifr;
 
 
  memset(&ifr, 0, sizeof(ifr));
  strcpy(ifr.ifr_name, "eth0");
  fd = socket(AF_INET, SOCK_DGRAM, 0);
  if (fd < 0) {
    perror("Cannot get control socket");
    return 70;
  }
  edata.cmd = 0x0000000a;
  ifr.ifr_data = (caddr_t)&edata;
  err = ioctl(fd, 0x8946, &ifr);
  if (err == 0) {
    fprintf(stdout, "Link detected: %s\n",
      edata.data ? "yes":"no");
  } else if (errno != EOPNOTSUPP) {
    perror("Cannot get link status");
  }
 return 0;
}

#include <net if.h=""> // IFF_RUNNING
 
//如果网卡已脸上网线，返回0，否则返回-1.
int check_nic(char *nic)
{
 struct ifreq ifr;
 int skfd = socket(AF_INET, SOCK_DGRAM, 0);
 
 strcpy(ifr.ifr_name, nic_name);
 if (ioctl(skfd, SIOCGIFFLAGS, &ifr) < 0)
 {
  return -1;
 }
 if(ifr.ifr_flags & IFF_RUNNING)
  return 0; // 网卡已插上网线
 else return -1;
}
</net>