xt_tcpudp.h

实现路由功能,nat地址转换,端口映射,网络放火墙功能.

#ifndef _XT_TCPUDP_H
#define _XT_TCPUDP_H

/* TCP matching stuff */
struct xt_tcp
{
	u_int16_t spts[2];			/* Source port range. */
	u_int16_t dpts[2];			/* Destination port range. */
	u_int8_t option;			/* TCP Option iff non-zero*/
	u_int8_t flg_mask;			/* TCP flags mask byte */
	u_int8_t flg_cmp;			/* TCP flags compare byte */
	u_int8_t invflags;			/* Inverse flags */
};

/* Values for "inv" field in struct ipt_tcp. */
#define XT_TCP_INV_SRCPT	0x01	/* Invert the sense of source ports. */
#define XT_TCP_INV_DSTPT	0x02	/* Invert the sense of dest ports. */
#define XT_TCP_INV_FLAGS	0x04	/* Invert the sense of TCP flags. */
#define XT_TCP_INV_OPTION	0x08	/* Invert the sense of option test. */
#define XT_TCP_INV_MASK		0x0F	/* All possible flags. */

/* UDP matching stuff */
struct xt_udp
{
	u_int16_t spts[2];			/* Source port range. */
	u_int16_t dpts[2];			/* Destination port range. */
	u_int8_t invflags;			/* Inverse flags */
};

/* Values for "invflags" field in struct ipt_udp. */
#define XT_UDP_INV_SRCPT	0x01	/* Invert the sense of source ports. */
#define XT_UDP_INV_DSTPT	0x02	/* Invert the sense of dest ports. */
#define XT_UDP_INV_MASK	0x03	/* All possible flags. */


#endif