[net-next-2.6.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/err.h>
#include <linux/slab.h>
#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"

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 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, 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))
{
	skb = skb_clone(skb, GFP_ATOMIC);
	if (!skb) {
		struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;

		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 *port;
	struct net_bridge_port *lport, *rport;
	struct net_bridge_port *prev;
	struct net_bridge_port_group *p;
	struct hlist_node *rp;

	prev = NULL;

	rp = br->router_list.first;
	p = mdst ? mdst->ports : NULL;
	while (p || rp) {
		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 = p->next;
		if ((unsigned long)rport >= (unsigned long)port)
			rp = rp->next;
	}

	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
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
025d89c2	14	#include <linux/err.h>
5a0e3ad6	15	#include <linux/slab.h>
1da177e4 LT	16	#include <linux/kernel.h>
	17	#include <linux/netdevice.h>
	18	#include <linux/skbuff.h>
85ca719e	19	#include <linux/if_vlan.h>
1da177e4 LT	20	#include <linux/netfilter_bridge.h>
	21	#include "br_private.h"
	22
87faf3cc DM	23	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	24	struct sk_buff *skb,
7f7708f0 MB	25	void (__packet_hook)(const struct net_bridge_port p,
	26	struct sk_buff *skb));
	27
9ef513be	28	/* Don't forward packets to originating port or forwarding diasabled */
9d6f229f	29	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	30	const struct sk_buff *skb)
1da177e4 LT	31	{
3982d3d2 FA	32	return (((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
3982d3d2 FA	33	p->state == BR_STATE_FORWARDING);
1da177e4 LT	34	}
1da177e4 LT	35
85ca719e SH	36	static inline unsigned packet_length(const struct sk_buff *skb)
	37	{
	38	return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
	39	}
	40
1da177e4 LT	41	int br_dev_queue_push_xmit(struct sk_buff *skb)
1da177e4 LT	42	{
7967168c	43	/* drop mtu oversized packets except gso */
89114afd	44	if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
1da177e4 LT	45	kfree_skb(skb);
1da177e4 LT	46	else {
1da177e4	47	/* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
3a13813e SH	48	if (nf_bridge_maybe_copy_header(skb))
3a13813e SH	49	kfree_skb(skb);
07317621	50	else {
3a13813e	51	skb_push(skb, ETH_HLEN);
1da177e4	52
3a13813e SH	53	dev_queue_xmit(skb);
3a13813e SH	54	}
1da177e4 LT	55	}
	56
	57	return 0;
	58	}
	59
	60	int br_forward_finish(struct sk_buff *skb)
	61	{
9ef513be SH	62	return NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
9ef513be SH	63	br_dev_queue_push_xmit);
1da177e4	64
1da177e4 LT	65	}
	66
	67	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	68	{
	69	skb->dev = to->dev;
1da177e4 LT	70	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
	71	br_forward_finish);
	72	}
	73
	74	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	75	{
	76	struct net_device *indev;
	77
4906f998 HX	78	if (skb_warn_if_lro(skb)) {
	79	kfree_skb(skb);
	80	return;
	81	}
	82
1da177e4 LT	83	indev = skb->dev;
1da177e4 LT	84	skb->dev = to->dev;
35fc92a9	85	skb_forward_csum(skb);
1da177e4 LT	86
	87	NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
	88	br_forward_finish);
	89	}
	90
	91	/* called with rcu_read_lock */
	92	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	93	{
	94	if (should_deliver(to, skb)) {
	95	__br_deliver(to, skb);
	96	return;
	97	}
	98
	99	kfree_skb(skb);
	100	}
	101
	102	/* called with rcu_read_lock */
7f7708f0	103	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	104	{
4906f998	105	if (should_deliver(to, skb)) {
7f7708f0 MB	106	if (skb0)
	107	deliver_clone(to, skb, __br_forward);
	108	else
	109	__br_forward(to, skb);
1da177e4 LT	110	return;
	111	}
	112
7f7708f0 MB	113	if (!skb0)
7f7708f0 MB	114	kfree_skb(skb);
1da177e4 LT	115	}
1da177e4 LT	116
87faf3cc DM	117	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	118	struct sk_buff *skb,
025d89c2 HX	119	void (__packet_hook)(const struct net_bridge_port p,
	120	struct sk_buff *skb))
	121	{
	122	skb = skb_clone(skb, GFP_ATOMIC);
	123	if (!skb) {
	124	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	125
	126	dev->stats.tx_dropped++;
	127	return -ENOMEM;
	128	}
	129
	130	__packet_hook(prev, skb);
	131	return 0;
	132	}
	133
	134	static struct net_bridge_port *maybe_deliver(
	135	struct net_bridge_port prev, struct net_bridge_port p,
	136	struct sk_buff *skb,
	137	void (__packet_hook)(const struct net_bridge_port p,
	138	struct sk_buff *skb))
	139	{
	140	int err;
	141
	142	if (!should_deliver(p, skb))
	143	return prev;
	144
	145	if (!prev)
	146	goto out;
	147
	148	err = deliver_clone(prev, skb, __packet_hook);
	149	if (err)
	150	return ERR_PTR(err);
	151
	152	out:
	153	return p;
	154	}
	155
1da177e4	156	/* called under bridge lock */
e081e1e3	157	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	158	struct sk_buff *skb0,
	159	void (__packet_hook)(const struct net_bridge_port p,
	160	struct sk_buff *skb))
1da177e4 LT	161	{
	162	struct net_bridge_port *p;
	163	struct net_bridge_port *prev;
	164
1da177e4 LT	165	prev = NULL;
	166
	167	list_for_each_entry_rcu(p, &br->port_list, list) {
025d89c2 HX	168	prev = maybe_deliver(prev, p, skb, __packet_hook);
	169	if (IS_ERR(prev))
	170	goto out;
1da177e4 LT	171	}
1da177e4 LT	172
b33084be HX	173	if (!prev)
	174	goto out;
	175
025d89c2 HX	176	if (skb0)
	177	deliver_clone(prev, skb, __packet_hook);
	178	else
	179	__packet_hook(prev, skb);
b33084be	180	return;
1da177e4	181
b33084be HX	182	out:
	183	if (!skb0)
	184	kfree_skb(skb);
1da177e4 LT	185	}
	186
	187
	188	/* called with rcu_read_lock */
e081e1e3	189	void br_flood_deliver(struct net_bridge br, struct sk_buff skb)
1da177e4	190	{
b33084be	191	br_flood(br, skb, NULL, __br_deliver);
1da177e4 LT	192	}
	193
	194	/* called under bridge lock */
b33084be HX	195	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
b33084be HX	196	struct sk_buff *skb2)
1da177e4	197	{
b33084be	198	br_flood(br, skb, skb2, __br_forward);
1da177e4	199	}
5cb5e947 HX	200
	201	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	202	/* called with rcu_read_lock */
	203	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	204	struct sk_buff skb, struct sk_buff skb0,
	205	void (*__packet_hook)(
	206	const struct net_bridge_port *p,
	207	struct sk_buff *skb))
	208	{
	209	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	210	struct net_bridge *br = netdev_priv(dev);
	211	struct net_bridge_port *port;
	212	struct net_bridge_port lport, rport;
	213	struct net_bridge_port *prev;
	214	struct net_bridge_port_group *p;
	215	struct hlist_node *rp;
	216
	217	prev = NULL;
	218
	219	rp = br->router_list.first;
	220	p = mdst ? mdst->ports : NULL;
	221	while (p \|\| rp) {
	222	lport = p ? p->port : NULL;
	223	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	224	NULL;
	225
	226	port = (unsigned long)lport > (unsigned long)rport ?
	227	lport : rport;
	228
	229	prev = maybe_deliver(prev, port, skb, __packet_hook);
	230	if (IS_ERR(prev))
	231	goto out;
	232
	233	if ((unsigned long)lport >= (unsigned long)port)
	234	p = p->next;
	235	if ((unsigned long)rport >= (unsigned long)port)
	236	rp = rp->next;
	237	}
	238
	239	if (!prev)
	240	goto out;
	241
	242	if (skb0)
	243	deliver_clone(prev, skb, __packet_hook);
	244	else
	245	__packet_hook(prev, skb);
	246	return;
	247
	248	out:
	249	if (!skb0)
	250	kfree_skb(skb);
	251	}
	252
	253	/* called with rcu_read_lock */
	254	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	255	struct sk_buff *skb)
	256	{
	257	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	258	}
	259
	260	/* called with rcu_read_lock */
	261	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	262	struct sk_buff skb, struct sk_buff skb2)
	263	{
264	br_multicast_flood(mdst, skb, skb2, __br_forward);
265	}
266	#endif