[linux-block.git] / net / bridge / br_forward.c

/*
 *	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/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 (((p->flags & BR_HAIRPIN_MODE) || 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 gso */
	if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
		kfree_skb(skb);
	else {
		/* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
		if (nf_bridge_maybe_copy_header(skb))
			kfree_skb(skb);
		else {
			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;

	if (skb_warn_if_lro(skb)) {
		kfree_skb(skb);
		return;
	}

	indev = skb->dev;
	skb->dev = to->dev;
	skb_forward_csum(skb);

	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,
	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) {
		if (should_deliver(p, skb)) {
			if (prev != NULL) {
				struct sk_buff *skb2;

				if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
					br->dev->stats.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)
{
	br_flood(br, skb, __br_deliver);
}

/* called under bridge lock */
void br_flood_forward(struct net_bridge *br, struct sk_buff *skb)
{
	br_flood(br, skb, __br_forward);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Forwarding decision
	3	* Linux ethernet bridge
	4	*
	5	* Authors:
	6	* Lennert Buytenhek <buytenh@gnu.org>
	7	*
1da177e4 LT	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the License, or (at your option) any later version.
	12	*/
	13
	14	#include <linux/kernel.h>
	15	#include <linux/netdevice.h>
	16	#include <linux/skbuff.h>
85ca719e	17	#include <linux/if_vlan.h>
1da177e4 LT	18	#include <linux/netfilter_bridge.h>
	19	#include "br_private.h"
	20
9ef513be	21	/* Don't forward packets to originating port or forwarding diasabled */
9d6f229f	22	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	23	const struct sk_buff *skb)
1da177e4 LT	24	{
3982d3d2 FA	25	return (((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
3982d3d2 FA	26	p->state == BR_STATE_FORWARDING);
1da177e4 LT	27	}
1da177e4 LT	28
85ca719e SH	29	static inline unsigned packet_length(const struct sk_buff *skb)
	30	{
	31	return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
	32	}
	33
1da177e4 LT	34	int br_dev_queue_push_xmit(struct sk_buff *skb)
1da177e4 LT	35	{
7967168c	36	/* drop mtu oversized packets except gso */
89114afd	37	if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
1da177e4 LT	38	kfree_skb(skb);
1da177e4 LT	39	else {
1da177e4	40	/* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
3a13813e SH	41	if (nf_bridge_maybe_copy_header(skb))
3a13813e SH	42	kfree_skb(skb);
07317621	43	else {
3a13813e	44	skb_push(skb, ETH_HLEN);
1da177e4	45
3a13813e SH	46	dev_queue_xmit(skb);
3a13813e SH	47	}
1da177e4 LT	48	}
	49
	50	return 0;
	51	}
	52
	53	int br_forward_finish(struct sk_buff *skb)
	54	{
9ef513be SH	55	return NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
9ef513be SH	56	br_dev_queue_push_xmit);
1da177e4	57
1da177e4 LT	58	}
	59
	60	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	61	{
	62	skb->dev = to->dev;
1da177e4 LT	63	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
	64	br_forward_finish);
	65	}
	66
	67	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	68	{
	69	struct net_device *indev;
	70
4906f998 HX	71	if (skb_warn_if_lro(skb)) {
	72	kfree_skb(skb);
	73	return;
	74	}
	75
1da177e4 LT	76	indev = skb->dev;
1da177e4 LT	77	skb->dev = to->dev;
35fc92a9	78	skb_forward_csum(skb);
1da177e4 LT	79
	80	NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
	81	br_forward_finish);
	82	}
	83
	84	/* called with rcu_read_lock */
	85	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	86	{
	87	if (should_deliver(to, skb)) {
	88	__br_deliver(to, skb);
	89	return;
	90	}
	91
	92	kfree_skb(skb);
	93	}
	94
	95	/* called with rcu_read_lock */
	96	void br_forward(const struct net_bridge_port to, struct sk_buff skb)
	97	{
4906f998	98	if (should_deliver(to, skb)) {
1da177e4 LT	99	__br_forward(to, skb);
	100	return;
	101	}
	102
	103	kfree_skb(skb);
	104	}
	105
	106	/* called under bridge lock */
e081e1e3	107	static void br_flood(struct net_bridge br, struct sk_buff skb,
9d6f229f	108	void (__packet_hook)(const struct net_bridge_port p,
1da177e4 LT	109	struct sk_buff *skb))
	110	{
	111	struct net_bridge_port *p;
	112	struct net_bridge_port *prev;
	113
1da177e4 LT	114	prev = NULL;
	115
	116	list_for_each_entry_rcu(p, &br->port_list, list) {
	117	if (should_deliver(p, skb)) {
	118	if (prev != NULL) {
	119	struct sk_buff *skb2;
	120
	121	if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL) {
a339f1c8	122	br->dev->stats.tx_dropped++;
1da177e4 LT	123	kfree_skb(skb);
	124	return;
	125	}
	126
	127	__packet_hook(prev, skb2);
	128	}
	129
	130	prev = p;
	131	}
	132	}
	133
	134	if (prev != NULL) {
	135	__packet_hook(prev, skb);
	136	return;
	137	}
	138
	139	kfree_skb(skb);
	140	}
	141
	142
	143	/* called with rcu_read_lock */
e081e1e3	144	void br_flood_deliver(struct net_bridge br, struct sk_buff skb)
1da177e4	145	{
e081e1e3	146	br_flood(br, skb, __br_deliver);
1da177e4 LT	147	}
	148
	149	/* called under bridge lock */
e081e1e3	150	void br_flood_forward(struct net_bridge br, struct sk_buff skb)
1da177e4	151	{
e081e1e3	152	br_flood(br, skb, __br_forward);
1da177e4	153	}