公网私网IP地址判断

/** 
 * 10.0.0.0    - 10.255.255.255
 * 172.16.0.0  - 172.31.255.255
 * 192.168.0.0 - 192.168.255.255
 */ 
static bool is_private_address(QString ip)
{
    uint32_t address = QHostAddress(ip).toIPv4Address();

    uint32_t check1 = (10 << 24);                // 0x0a000000
    uint32_t check2 = (172 << 24) + (16 << 16);  // 0xac100000
    uint32_t check3 = (192 << 24) + (168 << 16); // 0xc0a80000

    /* 10.0.0.0 - 10.255.255.255 */
    if ((address & 0x0f000000) == check1)
        return true;

    /* 172.16.0.0 - 172.31.255.255 */
    if ((address & 0xfff00000) == check2)
        return true;

    /* 192.168.0.0 - 192.168.255.255 */
    if ((address & 0xffff0000) == check3)
        return true;

    return false;
}