Bit Fields are Evil in Linux Kernel ... except linux/tcp.h has them!

but here is an example:

struct tcp_options_received {
/*  PAWS/RTTM data  */
    long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */
    u32 ts_recent;  /* Time stamp to echo next      */
    u32 rcv_tsval;  /* Time stamp value                 */
    u32 rcv_tsecr;  /* Time stamp echo reply            */
    u16     saw_tstamp : 1, /* Saw TIMESTAMP on last packet     */
        tstamp_ok : 1,  /* TIMESTAMP seen on SYN packet     */
        dsack : 1,  /* D-SACK is scheduled          */
        wscale_ok : 1,  /* Wscale seen on SYN packet        */
        sack_ok : 4,    /* SACK seen on SYN packet      */
        snd_wscale : 4, /* Window scaling received from sender  */
        rcv_wscale : 4; /* Window scaling to send to receiver   */
    u8  num_sacks;  /* Number of SACK blocks        */
    u16 user_mss;   /* mss requested by user in ioctl   */
    u16 mss_clamp;  /* Maximal mss, negotiated at connection setup */
};