/* *	Forwarding decision *	Linux ethernet bridge * *	Authors: *	Lennert Buytenhek		<buytenh@gnu.org> * *	$Id: br_forward.c,v 1.4 2001/08/14 22:05:57 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/skbuff.h>#include <linux/if_vlan.h>#include <linux/netfilter_bridge.h>#include "br_private.h" /* Don't forward packets to originating port or forwarding diasabled */static inline int should_deliver(const struct net_bridge_port *p, 				 const struct sk_buff *skb){	return (skb->dev != p->dev && p->state == BR_STATE_FORWARDING);} static inline unsigned packet_length(const struct sk_buff *skb){	return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);} int br_dev_queue_push_xmit(struct sk_buff *skb){	/* drop mtu oversized packets except tso */	if (packet_length(skb) > skb->dev->mtu && !skb_shinfo(skb)->tso_size)		kfree_skb(skb);	else {#ifdef CONFIG_BRIDGE_NETFILTER		/* ip_refrag calls ip_fragment, doesn't copy the MAC header. */		nf_bridge_maybe_copy_header(skb);#endif		skb_push(skb, ETH_HLEN); 		dev_queue_xmit(skb);	} 	return 0;} int br_forward_finish(struct sk_buff *skb){	return NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,		       br_dev_queue_push_xmit); } static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb){	skb->dev = to->dev;	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,			br_forward_finish);} static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb){	struct net_device *indev; 	indev = skb->dev;	skb->dev = to->dev;	skb->ip_summed = CHECKSUM_NONE; 	NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,			br_forward_finish);} /* called with rcu_read_lock */void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb){	if (should_deliver(to, skb)) {		__br_deliver(to, skb);		return;	} 	kfree_skb(skb);} /* called with rcu_read_lock */void br_forward(const struct net_bridge_port *to, struct sk_buff *skb){	if (should_deliver(to, skb)) {		__br_forward(to, skb);		return;	} 	kfree_skb(skb);} /* called under bridge lock */static void br_flood(struct net_bridge *br, struct sk_buff *skb, int clone,	void (*__packet_hook)(const struct net_bridge_port *p, 			      struct sk_buff *skb)){	struct net_bridge_port *p;	struct net_bridge_port *prev; 	if (clone) {		struct sk_buff *skb2; 		if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {			br->statistics.tx_dropped++;			return;		} 		skb = skb2;	} 	prev = NULL; 	list_for_each_entry_rcu(p, &br->port_list, list) {		if (should_deliver(p, skb)) {			if (prev != NULL) {				struct sk_buff *skb2; 				if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {					br->statistics.tx_dropped++;					kfree_skb(skb);					return;				} 				__packet_hook(prev, skb2);			} 			prev = p;		}	} 	if (prev != NULL) {		__packet_hook(prev, skb);		return;	} 	kfree_skb(skb);}  /* called with rcu_read_lock */void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, int clone){	br_flood(br, skb, clone, __br_deliver);} /* called under bridge lock */void br_flood_forward(struct net_bridge *br, struct sk_buff *skb, int clone){	br_flood(br, skb, clone, __br_forward);}