/* *	Forwarding decision *	Linux ethernet bridge * *	Authors: *	Lennert Buytenhek		<buytenh@gnu.org> * *	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/err.h>#include <linux/slab.h>#include <linux/kernel.h>#include <linux/netdevice.h>#include <linux/netpoll.h>#include <linux/skbuff.h>#include <linux/if_vlan.h>#include <linux/netfilter_bridge.h>#include "br_private.h" static int deliver_clone(const struct net_bridge_port *prev,			 struct sk_buff *skb,			 void (*__packet_hook)(const struct net_bridge_port *p,					       struct sk_buff *skb)); /* 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 (((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&		p->state == BR_STATE_FORWARDING);} static inline unsigned int 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){	/* ip_fragment doesn't copy the MAC header */	if (nf_bridge_maybe_copy_header(skb) ||	    (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))) {		kfree_skb(skb);	} else {		skb_push(skb, ETH_HLEN);		br_drop_fake_rtable(skb);		dev_queue_xmit(skb);	} 	return 0;} int br_forward_finish(struct sk_buff *skb){	return NF_HOOK(NFPROTO_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; 	if (unlikely(netpoll_tx_running(to->dev))) {		if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))			kfree_skb(skb);		else {			skb_push(skb, ETH_HLEN);			br_netpoll_send_skb(to, skb);		}		return;	} 	NF_HOOK(NFPROTO_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; 	if (skb_warn_if_lro(skb)) {		kfree_skb(skb);		return;	} 	indev = skb->dev;	skb->dev = to->dev;	skb_forward_csum(skb); 	NF_HOOK(NFPROTO_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 (to && 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, struct sk_buff *skb0){	if (should_deliver(to, skb)) {		if (skb0)			deliver_clone(to, skb, __br_forward);		else			__br_forward(to, skb);		return;	} 	if (!skb0)		kfree_skb(skb);} static int deliver_clone(const struct net_bridge_port *prev,			 struct sk_buff *skb,			 void (*__packet_hook)(const struct net_bridge_port *p,					       struct sk_buff *skb)){	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev; 	skb = skb_clone(skb, GFP_ATOMIC);	if (!skb) {		dev->stats.tx_dropped++;		return -ENOMEM;	} 	__packet_hook(prev, skb);	return 0;} static struct net_bridge_port *maybe_deliver(	struct net_bridge_port *prev, struct net_bridge_port *p,	struct sk_buff *skb,	void (*__packet_hook)(const struct net_bridge_port *p,			      struct sk_buff *skb)){	int err; 	if (!should_deliver(p, skb))		return prev; 	if (!prev)		goto out; 	err = deliver_clone(prev, skb, __packet_hook);	if (err)		return ERR_PTR(err); out:	return p;} /* called under bridge lock */static void br_flood(struct net_bridge *br, struct sk_buff *skb,		     struct sk_buff *skb0,		     void (*__packet_hook)(const struct net_bridge_port *p,					   struct sk_buff *skb)){	struct net_bridge_port *p;	struct net_bridge_port *prev; 	prev = NULL; 	list_for_each_entry_rcu(p, &br->port_list, list) {		prev = maybe_deliver(prev, p, skb, __packet_hook);		if (IS_ERR(prev))			goto out;	} 	if (!prev)		goto out; 	if (skb0)		deliver_clone(prev, skb, __packet_hook);	else		__packet_hook(prev, skb);	return; out:	if (!skb0)		kfree_skb(skb);}  /* called with rcu_read_lock */void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb){	br_flood(br, skb, NULL, __br_deliver);} /* called under bridge lock */void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,		      struct sk_buff *skb2){	br_flood(br, skb, skb2, __br_forward);} #ifdef CONFIG_BRIDGE_IGMP_SNOOPING/* called with rcu_read_lock */static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,			       struct sk_buff *skb, struct sk_buff *skb0,			       void (*__packet_hook)(					const struct net_bridge_port *p,					struct sk_buff *skb)){	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;	struct net_bridge *br = netdev_priv(dev);	struct net_bridge_port *prev = NULL;	struct net_bridge_port_group *p;	struct hlist_node *rp; 	rp = rcu_dereference(hlist_first_rcu(&br->router_list));	p = mdst ? rcu_dereference(mdst->ports) : NULL;	while (p || rp) {		struct net_bridge_port *port, *lport, *rport; 		lport = p ? p->port : NULL;		rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :			     NULL; 		port = (unsigned long)lport > (unsigned long)rport ?		       lport : rport; 		prev = maybe_deliver(prev, port, skb, __packet_hook);		if (IS_ERR(prev))			goto out; 		if ((unsigned long)lport >= (unsigned long)port)			p = rcu_dereference(p->next);		if ((unsigned long)rport >= (unsigned long)port)			rp = rcu_dereference(hlist_next_rcu(rp));	} 	if (!prev)		goto out; 	if (skb0)		deliver_clone(prev, skb, __packet_hook);	else		__packet_hook(prev, skb);	return; out:	if (!skb0)		kfree_skb(skb);} /* called with rcu_read_lock */void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,			  struct sk_buff *skb){	br_multicast_flood(mdst, skb, NULL, __br_deliver);} /* called with rcu_read_lock */void br_multicast_forward(struct net_bridge_mdb_entry *mdst,			  struct sk_buff *skb, struct sk_buff *skb2){	br_multicast_flood(mdst, skb, skb2, __br_forward);}#endif