#define TCP_CTL(flags, offset) (htons((flags) | ((offset) << 12)))
#define TCP_FLAGS(tcp_ctl) (ntohs(tcp_ctl) & 0x0fff)
+#define TCP_FLAGS_BE16(tcp_ctl) ((tcp_ctl) & htons(0x0fff))
#define TCP_OFFSET(tcp_ctl) (ntohs(tcp_ctl) >> 12)
#define TCP_HEADER_LEN 20