获取网络接口IP地址和掩码

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ifaddrs.h>

int get_ip_mask(const char* ifname, struct sockaddr_in* addr, struct sockaddr_in* mask)
{
        struct ifaddrs *ifcs;
        struct ifaddrs *ifc;

        char ip[64] = {};
        char nm[64] = {};
        int ret = 1;

        if(0 != getifaddrs(&ifcs))
                return -1;

        for(ifc = ifcs; NULL != ifc; ifc = ifc->ifa_next)
        {
                if (strcmp(ifname, ifc->ifa_name))
                {
                        continue;
                }
                if ((NULL != ifc->ifa_addr && ((struct sockaddr_in *)ifc->ifa_addr)->sin_addr.s_addr != 0)
                    && (NULL != ifc->ifa_netmask && ((struct sockaddr_in *)ifc->ifa_netmask)->sin_addr.s_addr != 0) )
                {
                        memcpy(addr, ifc->ifa_addr, sizeof(struct sockaddr_in));
                        memcpy(mask, ifc->ifa_netmask, sizeof(struct sockaddr_in));
                        ret = 0;
                        break;
                }
        }
        freeifaddrs(ifcs);
        return ret;
}

int main(int argc, char* argv[])
{
        struct sockaddr_in addr;
        struct sockaddr_in mask;

        if ( 0== get_ip_mask("eth0", &addr, &mask))
        {
                printf("found 0x%x, 0x%x\n", addr.sin_addr.s_addr, mask.sin_addr.s_addr);
        }
    return 0;
}