linux下 C语言 获取网卡信息：网卡名字 ipv4 ipv6。

#define _GNU_SOURCE    # required for NI_NUMERICHOST
#include <arpa/inet.h>
#include <sys/socket.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <netdb.h>

int main ()
{
  struct ifaddrs *ifap, *ifa;
  struct sockaddr_in6 *sa;
  struct sockaddr_in *sa4;
  char addr[INET6_ADDRSTRLEN];
  char addr4[INET_ADDRSTRLEN];

  getifaddrs (&ifap);
  for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
    if (ifa->ifa_addr->sa_family==AF_INET6) {
      sa = (struct sockaddr_in6 *) ifa->ifa_addr;
      getnameinfo(ifa->ifa_addr, sizeof(struct sockaddr_in6), addr,
                  sizeof(addr), NULL, 0, NI_NUMERICHOST);
      printf("Interface: %s\tAddress: %s\n", ifa->ifa_name, addr);
    } else if(ifa->ifa_addr->sa_family == AF_INET){
		sa4 = (struct sockaddr_in *)ifa->ifa_addr;
		getnameinfo(ifa->ifa_addr, sizeof(struct sockaddr_in), addr4,
                  sizeof(addr4), NULL, 0, NI_NUMERICHOST);
		/*inet_ntop(AF_INET, sa4, addr4, INET_ADDRSTRLEN);*/
		 printf("Interface: %s\tAddress: %s\n", ifa->ifa_name, addr4);
	}
  }

  freeifaddrs(ifap);
  return 0;
}