判断两个 IP 地址是否在同一子网 C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>

// 将点分十进制的 IP 地址转换为 32 位无符号整数
unsigned int ip_to_uint(const char *ip) {
    struct in_addr addr;
    if (inet_pton(AF_INET, ip, &addr) <= 0) {
        fprintf(stderr, "Invalid IP address: %s\n", ip);
        return 0;
    }
    return ntohl(addr.s_addr);
}

// 判断两个 IP 地址是否在同一子网
int is_same_subnet(const char *ip1, const char *ip2, const char *subnet_mask) {
    unsigned int ip1_int = ip_to_uint(ip1);
    unsigned int ip2_int = ip_to_uint(ip2);
    unsigned int mask_int = ip_to_uint(subnet_mask);

    if (ip1_int == 0 || ip2_int == 0 || mask_int == 0) {
        return 0;
    }

    // 计算网络地址
    unsigned int network1 = ip1_int & mask_int;
    unsigned int network2 = ip2_int & mask_int;

    return network1 == network2;
}

int main() {
    const char *ip1 = "192.168.1.100";
    const char *ip2 = "192.168.1.200";
    const char *subnet_mask = "255.255.255.0";

    if (is_same_subnet(ip1, ip2, subnet_mask)) {
        printf("%s 和 %s 属于同一子网。\n", ip1, ip2);
    } else {
        printf("%s 和 %s 不属于同一子网。\n", ip1, ip2);
    }

    return 0;
}