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

void network4(const char* network, int prefix) {
        struct in_addr inaddr;
        // Convert from human view to network bytes
        if (inet_pton(AF_INET, network, &inaddr) == 0) {
                printf("Invalid IP address\n");
                return;
        }
        // Convert from network bytes to local
        uint32_t ip = ntohl(inaddr.s_addr);

        // Calculate mask and net
        uint32_t mask = (prefix == 0) ? 0 : (~0U << (32 - prefix));
        uint32_t net = ip & mask;
        uint32_t fip = net + 1;

        // Convert net address bytes to network order
        struct in_addr net_addr;
        net_addr.s_addr = htonl(net);
        // Convert mask bytes to network order
        struct in_addr mask_addr;
        mask_addr.s_addr = htonl(mask);
        // Convert mask bytes to network order
        struct in_addr fip_addr;
        fip_addr.s_addr = htonl(fip);

        printf("IP:      %s/%d\n", network, prefix);
        printf("Netmask: %s\n", inet_ntoa(mask_addr));
        printf("Network: %s\n", inet_ntoa(net_addr));
        printf("First:   %s\n", inet_ntoa(fip_addr));
}

int main() {
        network4("192.168.1.154", 26);
        return 0;
}