C/C++ snippet: between_addr()

#include <errno.h> /* errno */
#include <arpa/inet.h> /* htonl */
#include <netinet/in.h> /* in_addr_t */

/**
 * @param start start IP adress in host byte order
 * @param end end IP address in host byte order
 * @param addr_cb callback
 * @param data callback argument.
 * @return If failed, between_addr() returns -1. Otherwise, retrun a value from callback
 */
int between_addr(uint32_t start, uint32_t end, int (*addr_cb)(in_add_t, const void *), void *data)
{
    int ret = -1;
    uint32_t addr, limit;

    if (!addr_cb) {
        errno = EINVAL;
        return ret;
    }

    addr = start < end ? start : end;
    limit = start > end ? end : start;

    for (; addr < limit; addr++) {
        ret = addr_cb(htonl(addr), data);
        if (!ret)
            break;
    }

    return ret;
}

C/C++ snippet: calc_network(), calc_broadcast()

計算網段

#include <netinet/in.h> /* in_addr_t */

in_addr_t calc_network(in_addr_t addr, in_addr_t netmask)
{
        return addr & netmask;
}

計算 broadcast

#include <netinet/in.h> /* in_addr_t */

in_addr_t calc_broadcast(in_addr_t addr, in_addr_t netmask)
{
        return addr | ~netmask;
}