/* *	Handle incoming frames *	Linux ethernet bridge * *	Authors: *	Lennert Buytenhek		<buytenh@gnu.org> * *	$Id: br_input.c,v 1.10 2001/12/24 04:50:20 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/netfilter_bridge.h>#include "br_private.h" /* Bridge group multicast address 802.1d (pg 51). */const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; 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; 	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,		netif_receive_skb);} /* note: already called with rcu_read_lock (preempt_disabled) */int br_handle_frame_finish(struct sk_buff *skb){	const unsigned char *dest = eth_hdr(skb)->h_dest;	struct net_bridge_port *p = rcu_dereference(skb->dev->br_port);	struct net_bridge *br;	struct net_bridge_fdb_entry *dst;	int passedup = 0; 	if (!p || p->state == BR_STATE_DISABLED)		goto drop; 	/* insert into forwarding database after filtering to avoid spoofing */	br = p->br;	br_fdb_update(br, p, eth_hdr(skb)->h_source); 	if (p->state == BR_STATE_LEARNING)		goto drop; 	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 (is_multicast_ether_addr(dest)) {		br->statistics.multicast++;		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);		goto out;	} 	if (dst != NULL) {		br_forward(dst->dst, skb);		goto out;	} 	br_flood_forward(br, skb, 0); out:	return 0;drop:	kfree_skb(skb);	goto out;} /* note: already called with rcu_read_lock (preempt_disabled) */static int br_handle_local_finish(struct sk_buff *skb){	struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); 	if (p && p->state != BR_STATE_DISABLED)		br_fdb_update(p->br, p, eth_hdr(skb)->h_source); 	return 0;	 /* process further */} /* Does address match the link local multicast address. * 01:80:c2:00:00:0X */static inline int is_link_local(const unsigned char *dest){	return memcmp(dest, br_group_address, 5) == 0 && (dest[5] & 0xf0) == 0;} /* * Called via br_handle_frame_hook. * Return 0 if *pskb should be processed furthur *	  1 if *pskb is handled * note: already called with rcu_read_lock (preempt_disabled)  */int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb){	struct sk_buff *skb = *pskb;	const unsigned char *dest = eth_hdr(skb)->h_dest; 	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))		goto err; 	if (unlikely(is_link_local(dest))) {		skb->pkt_type = PACKET_HOST;		return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,			       NULL, br_handle_local_finish) != 0;	} 	if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) {		if (br_should_route_hook) {			if (br_should_route_hook(pskb)) 				return 0;			skb = *pskb;			dest = eth_hdr(skb)->h_dest;		} 		if (!compare_ether_addr(p->br->dev->dev_addr, dest))			skb->pkt_type = PACKET_HOST; 		NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,			br_handle_frame_finish);		return 1;	} err:	kfree_skb(skb);	return 1;}