如何向 ipv4 数据包添加选项？

问：

我正在用 C 语言开发一个网络工具，它允许我向主机发送自定义数据包。到目前为止，一切都很好，但我决定实施 IPv4 选项，但我没有找到任何关于如何做到这一点的信息。

我找到了，但我不知道如何使用它来实现它：struct optionsstruct iphdr

struct options {
__u32       faddr;              /* Saved first hop address */
unsigned char   optlen;
unsigned char srr;
unsigned char rr;
unsigned char ts;
unsigned char is_setbyuser:1,           /* Set by setsockopt?           */
            is_data:1,          /* Options in __data, rather than skb   */
            is_strictroute:1,       /* Strict source route          */
            srr_is_hit:1,           /* Packet destination addr was our one  */
            is_changed:1,           /* IP checksum more not valid       */  
            rr_needaddr:1,          /* Need to record addr of outgoing dev  */
            ts_needtime:1,          /* Need to record timestamp     */
            ts_needaddr:1;          /* Need to record addr of outgoing dev  */
 unsigned char __pad1;
 unsigned char __pad2;
 unsigned char __pad3;
 unsigned char __data[0];
 };