IPv6子网计算器

讯享网

/* * CREATE BY BCTECH * * * @Author: Gu * * @Date: 2021-06-04 08:41:51 * * @Last Modified by: Gu * * @Last Modified time: 2021-06-07 21:31:24 */ #include <stdio.h> #include <stdlib.h> #include <math.h> #include <arpa/inet.h> #include <string.h> //网络字节序 / * [ip_to_str description] * @Author gu * @DateTime 2021-06-04T08:43:20+0800 * @Description 整型数IP转成字符串 * @param str [description] * @param ip [description] * @return [description] */ int ip_to_str(char *str, unsigned int *ip) { 
    int domain; unsigned int ipv6add[4]; if (ip[0] == 0 && ip[1] == 0 && ip[2] == 0) { 
    domain = AF_INET; ipv6add[0] = ip[3]; ipv6add[1] = 0; ipv6add[2] = 0; ipv6add[3] = 0; } else { 
    domain = AF_INET6; ipv6add[0] = ip[0]; ipv6add[1] = ip[1]; ipv6add[2] = ip[2]; ipv6add[3] = ip[3]; } if (inet_ntop(domain, ipv6add, str, INET6_ADDRSTRLEN) == NULL) { 
    return -1; } return 0; } //网络字节序 / * [str_to_ip description] * @Author gu * @DateTime 2021-06-04T08:43:49+0800 * @Description IP地址转成整型数 * @param str [description] * @param ip [description] * @return [description] */ int str_to_ip(char *str, unsigned int *ip) { 
    int Afamily; ip[0] = 0; ip[1] = 0; ip[2] = 0; ip[3] = 0; if (strstr(str, ":") != NULL) { 
    Afamily = AF_INET6; } else { 
    Afamily = AF_INET; } if (inet_pton(Afamily, str, ip) <= 0) { 
    return -1; } else { 
    // ntohl(ip);//网络字节序转主机字节序 } return 0; } //gcc -Wall -o subnet_calculat subnet_calculat.c -lm int main(int argc, char const *argv[]) { 
    char *ipstr = argv[1];//IP地址 int changenum = 0;//用来求划分后的前缀 int prefix = atoi(argv[2]);//IP子网 int need_prefix = 0;//划分后的子网前缀 int movenum = 0, runmove = 0;//二进制移动值 unsigned int tmpvalue = 0;//公用临时变量 unsigned int tmpvalue2 = 0; unsigned int tmpvalue3 = 0; unsigned int tmpvalue4 = 0; long long int run = 0;//遍历子网个数变量 long long int runtime = 0;//子网个数 unsigned int ip[4] = { 
   0}; int res = -1; char iptemp[64]; unsigned int need_ip[4] = { 
   0};//IP中转变量 if (strstr(argv[3], "/")) { 
   //按子网前缀划分 changenum = atoi(argv[3] + 1) - prefix; if (changenum < 0) { 
    printf("error select prefix should be more than ip_prefix!\n"); return 1; } } else { 
   //按需要的子网个数划分 int testnum = atoi(argv[3]); //要划分的个数/划分的子网 double lognum = (log10(testnum) / log10(2)); if (floor(lognum + 0.5) == (lognum)) { 
   //取整 changenum = round(lognum); //取划分的子网数跟2的对数 } else { 
    changenum = round(lognum + 0.5); //取划分的子网数跟2的对数 } } need_prefix = prefix + changenum; res = str_to_ip(ipstr, ip); if (res < 0) { 
    printf("str_to_ip error!\n"); return 0; } runtime = pow(2, changenum); if (runtime <= 0) { 
    runtime = 1; } for (run = 0; run < runtime ; run++) { 
    need_ip[0] = ip[0]; need_ip[1] = ip[1]; need_ip[2] = ip[2]; need_ip[3] = ip[3]; if (need_prefix <= 32) { 
   //结果子网小于等于32，操作整型IP地址的第一位 tmpvalue = htonl(need_ip[0]);//主机字节序转网络字节序 movenum = 32 + changenum - need_prefix; if (movenum < 0) { 
    printf("error no more subnet!\n"); return 0; } tmpvalue2 = (((tmpvalue >> (movenum)) << changenum) | run) << (movenum - changenum); need_ip[0] = ntohl(tmpvalue2); } else if (need_prefix <= 64) { 
   //结果子网小于等于64大于32，操作整型IP地址的第一和二位 movenum = 64 - need_prefix; if (movenum < 0) { 
    printf("error no more subnet!\n"); return 0; } runmove = need_prefix - 64; tmpvalue = htonl(need_ip[0]); tmpvalue2 = (tmpvalue | (run >> runmove)); need_ip[0] = ntohl(tmpvalue2); tmpvalue3 = htonl(need_ip[1]); tmpvalue4 = (((tmpvalue3 >> (movenum - 1)) + run) << movenum); need_ip[1] = (ntohl(tmpvalue4)); } else if (need_prefix <= 96) { 
   //结果子网小于等于96大于64，操作整型IP地址的第一和三位 movenum = 96 - need_prefix; if (movenum < 0) { 
    printf("error no more subnet!\n"); return 0; } runmove = need_prefix - 96; tmpvalue = htonl(need_ip[1]); tmpvalue2 = (tmpvalue | (run >> runmove)); need_ip[1] = ntohl(tmpvalue2); tmpvalue3 = htonl(need_ip[2]); tmpvalue4 = (((tmpvalue3 >> (movenum - 1)) + run) << movenum); need_ip[2] = (ntohl(tmpvalue4));//网络字节序转主机字节序 } else { 
   //结果子网大于96，操作整型IP地址的第一和四位 movenum = 128 - need_prefix; if (movenum < 0) { 
    printf("error no more subnet!\n"); return 0; } else { 
    tmpvalue2 = (((tmpvalue >> (movenum - 1)) + run) << movenum); } runmove = need_prefix - 128; tmpvalue = htonl(need_ip[2]); tmpvalue2 = (tmpvalue | (run >> runmove)); need_ip[2] = ntohl(tmpvalue2); tmpvalue3 = htonl(need_ip[3]); tmpvalue4 = (((tmpvalue3 >> (movenum - 1)) + run) << movenum); need_ip[3] = (ntohl(tmpvalue4)); } memset(iptemp, 0, sizeof(iptemp)); res = ip_to_str(iptemp, need_ip); if (res < 0) { 
    printf("ip_to_str error!\n"); return 0; } } return 0; } 

我自己的基本测试是没什么问题的，有的问题就是当子网的地址数或者子网数过多超过double最大值时，会有问题，所以如果使用尽量不要计算过大的子网。（其实我也是一知半解，所以不太好描述为什么这样写，反正代码他就是能用了哈哈哈哈哈哈哈哈）等我真的搞懂了我就再解释下吧。哈哈哈！