linux 下ip地址转换

/*linux 下IP地址转换*/

#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>

/*1.整形转换成字符串格式*/
void ipv4_int_to_str(char *ipv4, unsigned int a)
{
    struct in_addr  addr;

    addr.s_addr =  a;
    char *ip = inet_ntoa(addr);
    strcpy(ipv4, ip);
   
}

void ipv6_int_to_str(char *IPdotdec, unsigned int ipv6_addr[])
{  
    struct in6_addr s;
    int i;
    int ipv6[4];
    for(i = 0; i < 4; i++) {
        ipv6[i] = htonl(ipv6_addr[i]);
    }
   
    memcpy(s.s6_addr,ipv6,4*sizeof(int));
   
    inet_ntop(AF_INET6, (void *)&s, IPdotdec, INET6_ADDRSTRLEN);

}

/* 2.字符串转换成整形格式*/
void ipv4_str_to_int(char *ipv4, struct in_addr *s)
{
    /*也可以使用inet_addr函数*/
    inet_pton(AF_INET, ipv4, (void*)s);

}

void ipv6_str_to_int(char *ipaddr, unsigned int *ipv6)
{
    struct in6_addr dst;
    inet_pton(AF_INET6, ipaddr, (void *)&dst);
    memcpy(ipv6, dst.s6_addr, sizeof(dst.s6_addr));

}

/*子网掩码地址, 转换为一个CIDR值*/

 int mask_to_cidr(u_int32_t mask)
{
    int i, n = 0,bits;
   
    bits = sizeof(u_int32_t) * 8;
    for(i = bits - 1; i >= 0; i--) {
        if (mask & (0x01 << i)) {
            n++;    
        }
    }
   
    return n;
}

 

int main(int argc, char **argv)
{
    /*整形转换为字符型*/
    char ipv4_s[30];
    ipv4_int_to_str(ipv4_s, 84215041);
    printf("ipv4 string addr:%s\n", ipv4_s);

    char ipv6_s[50];
    unsigned int ipv6_i[4];//以一个无符号整形数组存放ipv6地址
    ipv6_i[0] = 0x20140000;
    ipv6_i[1] = 0x0;
    ipv6_i[2] = 0x0;
    ipv6_i[3] = 0x1;
    ipv6_int_to_str(ipv6_s, ipv6_i);
    printf("ipv4 string addr:%s\n", ipv6_s);

    /*字符类型转换成整形*/
    strcpy(ipv4_s,"192.168.20.100");
    struct in_addr s;
    ipv4_str_to_int(ipv4_s,&s);
    printf("ipv4 integar addr:%x\n",s.s_addr);

    strcpy(ipv6_s,"2014::1");
    unsigned int ipv6[4];
    ipv6_str_to_int(ipv6_s, ipv6);
    int i;
    printf("ipv6 integar addr:");
    for(i=0;i<4;i++) {
        printf("%x ",htonl(ipv6[i]));
    }
    printf("\n");
   
    return 0;
}