1. 根目录:
2. include
3. net
4. dn_route.h

#ifndef _NET_DN_ROUTE_H
#define _NET_DN_ROUTE_H

/******************************************************************************
    (c) 1995-1998 E.M. Serrat		emserrat@geocities.com
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
*******************************************************************************/

extern struct sk_buff *dn_alloc_skb(struct sock *sk, int size, gfp_t pri);
extern int dn_route_output_sock(struct dst_entry **pprt, struct flowidn *, struct sock *sk, int flags);
extern int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb);
extern void dn_rt_cache_flush(int delay);

/* Masks for flags field */
#define DN_RT_F_PID 0x07 /* Mask for packet type                      */
#define DN_RT_F_PF  0x80 /* Padding Follows                           */
#define DN_RT_F_VER 0x40 /* Version =0 discard packet if ==1          */
#define DN_RT_F_IE  0x20 /* Intra Ethernet, Reserved in short pkt     */
#define DN_RT_F_RTS 0x10 /* Packet is being returned to sender        */
#define DN_RT_F_RQR 0x08 /* Return packet to sender upon non-delivery */

/* Mask for types of routing packets */
#define DN_RT_PKT_MSK   0x06
/* Types of routing packets */
#define DN_RT_PKT_SHORT 0x02 /* Short routing packet */
#define DN_RT_PKT_LONG  0x06 /* Long routing packet  */

/* Mask for control/routing selection */
#define DN_RT_PKT_CNTL  0x01 /* Set to 1 if a control packet  */
/* Types of control packets */
#define DN_RT_CNTL_MSK  0x0f /* Mask for control packets      */
#define DN_RT_PKT_INIT  0x01 /* Initialisation packet         */
#define DN_RT_PKT_VERI  0x03 /* Verification Message          */
#define DN_RT_PKT_HELO  0x05 /* Hello and Test Message        */
#define DN_RT_PKT_L1RT  0x07 /* Level 1 Routing Message       */
#define DN_RT_PKT_L2RT  0x09 /* Level 2 Routing Message       */
#define DN_RT_PKT_ERTH  0x0b /* Ethernet Router Hello         */
#define DN_RT_PKT_EEDH  0x0d /* Ethernet EndNode Hello        */

/* Values for info field in hello message */
#define DN_RT_INFO_TYPE 0x03 /* Type mask                     */
#define DN_RT_INFO_L1RT 0x02 /* L1 Router                     */
#define DN_RT_INFO_L2RT 0x01 /* L2 Router                     */
#define DN_RT_INFO_ENDN 0x03 /* EndNode                       */
#define DN_RT_INFO_VERI 0x04 /* Verification Reqd.            */
#define DN_RT_INFO_RJCT 0x08 /* Reject Flag, Reserved         */
#define DN_RT_INFO_VFLD 0x10 /* Verification Failed, Reserved */
#define DN_RT_INFO_NOML 0x20 /* No Multicast traffic accepted */
#define DN_RT_INFO_BLKR 0x40 /* Blocking Requested            */

/*
 * The fl structure is what we used to look up the route.
 * The rt_saddr & rt_daddr entries are the same as key.saddr & key.daddr
 * except for local input routes, where the rt_saddr = fl.fld_dst and
 * rt_daddr = fl.fld_src to allow the route to be used for returning
 * packets to the originating host.
 */
struct dn_route {
	struct dst_entry dst;

	struct flowidn fld;

	__le16 rt_saddr;
	__le16 rt_daddr;
	__le16 rt_gateway;
	__le16 rt_local_src;	/* Source used for forwarding packets */
	__le16 rt_src_map;
	__le16 rt_dst_map;

	unsigned rt_flags;
	unsigned rt_type;
};

static inline bool dn_is_input_route(struct dn_route *rt)
{
	return rt->fld.flowidn_iif != 0;
}

static inline bool dn_is_output_route(struct dn_route *rt)
{
	return rt->fld.flowidn_iif == 0;
}

extern void dn_route_init(void);
extern void dn_route_cleanup(void);

#include <net/sock.h>
#include <linux/if_arp.h>

static inline void dn_rt_send(struct sk_buff *skb)
{
	dev_queue_xmit(skb);
}

static inline void dn_rt_finish_output(struct sk_buff *skb, char *dst, char *src)
{
	struct net_device *dev = skb->dev;

	if ((dev->type != ARPHRD_ETHER) && (dev->type != ARPHRD_LOOPBACK))
		dst = NULL;

	if (dev_hard_header(skb, dev, ETH_P_DNA_RT, dst, src, skb->len) >= 0)
		dn_rt_send(skb);
	else
		kfree_skb(skb);
}

#endif /* _NET_DN_ROUTE_H */