/*
 *	Handle incoming frames
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<buytenh@gnu.org>
 *
 *	$Id: br_input.c,v 1.9.2.1 2001/12/24 04:50:05 davem Exp $
 *
 *	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 (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_bridge.h>
#include <linux/netfilter_bridge.h>
#include "br_private.h"
#ifdef BR_CRYPT_IP
#include <linux/ip.h>
#endif

unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };

static int br_pass_frame_up_finish(struct sk_buff *skb)
{
#ifdef CONFIG_NETFILTER_DEBUG
	skb->nf_debug = 0;
#endif
	netif_rx(skb);

	return 0;
}

static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
{
	struct net_device *indev;

	br->statistics.rx_packets++;
	br->statistics.rx_bytes += skb->len;

	indev = skb->dev;
	skb->dev = &br->dev;
	skb->pkt_type = PACKET_HOST;
	skb_push(skb, ETH_HLEN);
	skb->protocol = eth_type_trans(skb, &br->dev);

	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
			br_pass_frame_up_finish);
}

int br_handle_frame_finish(struct sk_buff *skb)
{
	struct net_bridge *br;
	unsigned char *dest;
	struct net_bridge_fdb_entry *dst;
	struct net_bridge_port *p;
	int passedup;

	dest = skb->mac.ethernet->h_dest;

	p = skb->dev->br_port;
	if (p == NULL)
		goto err_nolock;

	br = p->br;
	read_lock(&br->lock);
	if (skb->dev->br_port == NULL)
		goto err;

	passedup = 0;
	if (br->dev.flags & IFF_PROMISC) {
		struct sk_buff *skb2;

		skb2 = skb_clone(skb, GFP_ATOMIC);
		if (skb2 != NULL) {
			passedup = 1;
			br_pass_frame_up(br, skb2);
		}
	}

	if (dest[0] & 1) {
		br_flood_forward(br, skb, !passedup);
		if (!passedup)
			br_pass_frame_up(br, skb);
		goto out;
	}

	dst = br_fdb_get(br, dest);
	if (dst != NULL && dst->is_local) {
		if (!passedup)
			br_pass_frame_up(br, skb);
		else
			kfree_skb(skb);
		br_fdb_put(dst);
		goto out;
	}

	if (dst != NULL) {
		br_forward(dst->dst, skb);
		br_fdb_put(dst);
		goto out;
	}

	br_flood_forward(br, skb, 0);

out:
	read_unlock(&br->lock);
	return 0;

err:
	read_unlock(&br->lock);
err_nolock:
	kfree_skb(skb);
	return 0;
}

int br_handle_frame(struct sk_buff *skb)
{
	struct net_bridge *br;
	struct net_bridge_port *p;
	unsigned char *dest;
	aes_ctx *context;

#ifdef BR_CRYPT_IP
	__u32 daddr;
	static unsigned char ipdest[ETH_ALEN];
#endif

	dest = skb->mac.ethernet->h_dest;

	p = skb->dev->br_port;
	if (p == NULL)
		goto err_nolock;

	br = p->br;
	read_lock(&br->lock);
	if (skb->dev->br_port == NULL)
		goto err;

	if (!(br->dev.flags & IFF_UP) ||
	    p->state == BR_STATE_DISABLED)
		goto err;

	if (skb->mac.ethernet->h_source[0] & 1)
		goto err;

	if (p->state == BR_STATE_LEARNING ||
	    p->state == BR_STATE_FORWARDING)
		br_fdb_insert(br, p, skb->mac.ethernet->h_source, 0);

	if (br->stp_enabled &&
	    !memcmp(dest, bridge_ula, 5) &&
	    !(dest[5] & 0xF0))
		goto handle_special_frame;

#ifdef BR_CRYPT_IP
	/* Encrypt or decrypt by destination IP. */
	if (ntohs(skb->protocol) != ETH_P_IP)
		goto forward;
	
	/* get the destination IP and pretend it's a MAC address */
	daddr = (skb->nh.iph)->daddr;
	ipdest[0] = (unsigned char)daddr;
	ipdest[1] = (unsigned char)(daddr >> 8);
	ipdest[2] = (unsigned char)(daddr >> 16);
	ipdest[3] = (unsigned char)(daddr >> 24);
	ipdest[4] = 0;
	ipdest[5] = 0;

	dest = ipdest;
#endif

	/* if not forwarding, don't encrypt or decrypt */
	if (p->state == BR_STATE_FORWARDING) {
		if ((context = br_chash_get_enc(br, dest))) {
			if (br_aes_encrypt_frame(context, skb) < 0)
				goto err;
		}
		/*
		else if ((context = br_chash_get_dec(br, dest))) {
			if (br_aes_decrypt_frame(context, skb) < 0)
				goto err;
		}
		*/
	}

 forward:	
	if (p->state == BR_STATE_FORWARDING) {
		if (br_should_route_hook && br_should_route_hook(&skb)) {
			read_unlock(&br->lock);
			return -1;
		}

		NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
			br_handle_frame_finish);
		read_unlock(&br->lock);
		return 0;
	}

 err:
	read_unlock(&br->lock);
 err_nolock:
	kfree_skb(skb);
	return 0;

handle_special_frame:
	if (!dest[5]) {
		NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,NULL,
			br_stp_handle_bpdu);
		read_unlock(&br->lock);
		return 0;
	}

	read_unlock(&br->lock);
	kfree_skb(skb);
	return 0;
}
