root/include/linux/netfilter_ipv4/ip_queue.h

INCLUDED FROM

/*
 * This is a module which is used for queueing IPv4 packets and
 * communicating with userspace via netlink.
 *
 * (C) 2000 James Morris, this code is GPL.
 */
#ifndef _IP_QUEUE_H
#define _IP_QUEUE_H

#ifdef __KERNEL__
#ifdef DEBUG_IPQ
#define QDEBUG(x...) printk(KERN_DEBUG ## x)
#else
#define QDEBUG(x...)
#endif  /* DEBUG_IPQ */
#else
#include <net/if.h>
#endif  /* ! __KERNEL__ */

/* Messages sent from kernel */
typedef struct ipq_packet_msg {
        unsigned long packet_id;        /* ID of queued packet */
        unsigned long mark;             /* Netfilter mark value */
        long timestamp_sec;             /* Packet arrival time (seconds) */
        long timestamp_usec;            /* Packet arrvial time (+useconds) */
        unsigned int hook;              /* Netfilter hook we rode in on */
        char indev_name[IFNAMSIZ];      /* Name of incoming interface */
        char outdev_name[IFNAMSIZ];     /* Name of outgoing interface */
        __be16 hw_protocol;             /* Hardware protocol (network order) */
        unsigned short hw_type;         /* Hardware type */
        unsigned char hw_addrlen;       /* Hardware address length */
        unsigned char hw_addr[8];       /* Hardware address */
        size_t data_len;                /* Length of packet data */
        unsigned char payload[0];       /* Optional packet data */
} ipq_packet_msg_t;

/* Messages sent from userspace */
typedef struct ipq_mode_msg {
        unsigned char value;            /* Requested mode */
        size_t range;                   /* Optional range of packet requested */
} ipq_mode_msg_t;

typedef struct ipq_verdict_msg {
        unsigned int value;             /* Verdict to hand to netfilter */
        unsigned long id;               /* Packet ID for this verdict */
        size_t data_len;                /* Length of replacement data */
        unsigned char payload[0];       /* Optional replacement packet */
} ipq_verdict_msg_t;

typedef struct ipq_peer_msg {
        union {
                ipq_verdict_msg_t verdict;
                ipq_mode_msg_t mode;
        } msg;
} ipq_peer_msg_t;

/* Packet delivery modes */
enum {
        IPQ_COPY_NONE,          /* Initial mode, packets are dropped */
        IPQ_COPY_META,          /* Copy metadata */
        IPQ_COPY_PACKET         /* Copy metadata + packet (range) */
};
#define IPQ_COPY_MAX IPQ_COPY_PACKET

/* Types of messages */
#define IPQM_BASE       0x10    /* standard netlink messages below this */
#define IPQM_MODE       (IPQM_BASE + 1)         /* Mode request from peer */
#define IPQM_VERDICT    (IPQM_BASE + 2)         /* Verdict from peer */ 
#define IPQM_PACKET     (IPQM_BASE + 3)         /* Packet from kernel */
#define IPQM_MAX        (IPQM_BASE + 4)

#endif /*_IP_QUEUE_H*/