[deliverable/linux.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/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 disabled */
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) &&
		br_allowed_egress(p->br, nbp_get_vlan_info(p), skb) &&
		p->state == BR_STATE_FORWARDING;
}

int br_dev_queue_push_xmit(struct sk_buff *skb)
{
	if (!is_skb_forwardable(skb->dev, skb)) {
		kfree_skb(skb);
	} else {
		skb_push(skb, ETH_HLEN);
		br_drop_fake_rtable(skb);
		dev_queue_xmit(skb);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);

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);

}
EXPORT_SYMBOL_GPL(br_forward_finish);

static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
{
	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	if (!skb)
		return;

	skb->dev = to->dev;

	if (unlikely(netpoll_tx_running(to->br->dev))) {
		if (!is_skb_forwardable(skb->dev, 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;
	}

	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	if (!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);
}
EXPORT_SYMBOL_GPL(br_deliver);

/* 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),
		     bool unicast)
{
	struct net_bridge_port *p;
	struct net_bridge_port *prev;

	prev = NULL;

	list_for_each_entry_rcu(p, &br->port_list, list) {
		/* Do not flood unicast traffic to ports that turn it off */
		if (unicast && !(p->flags & BR_FLOOD))
			continue;

		/* Do not flood to ports that enable proxy ARP */
		if (p->flags & BR_PROXYARP)
			continue;
		if ((p->flags & BR_PROXYARP_WIFI) &&
		    BR_INPUT_SKB_CB(skb)->proxyarp_replied)
			continue;

		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, bool unicast)
{
	br_flood(br, skb, NULL, __br_deliver, unicast);
}

/* called under bridge lock */
void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
		      struct sk_buff *skb2, bool unicast)
{
	br_flood(br, skb, skb2, __br_forward, unicast);
}

#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
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>
1da177e4 LT	17	#include <linux/netdevice.h>
c06ee961	18	#include <linux/netpoll.h>
1da177e4	19	#include <linux/skbuff.h>
85ca719e	20	#include <linux/if_vlan.h>
1da177e4 LT	21	#include <linux/netfilter_bridge.h>
	22	#include "br_private.h"
	23
87faf3cc DM	24	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	25	struct sk_buff *skb,
7f7708f0 MB	26	void (__packet_hook)(const struct net_bridge_port p,
	27	struct sk_buff *skb));
	28
1a81a2e0	29	/* Don't forward packets to originating port or forwarding disabled */
9d6f229f	30	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	31	const struct sk_buff *skb)
1da177e4 LT	32	{
a97bfc1d	33	return ((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
85f46c6b	34	br_allowed_egress(p->br, nbp_get_vlan_info(p), skb) &&
a97bfc1d	35	p->state == BR_STATE_FORWARDING;
1da177e4 LT	36	}
	37
	38	int br_dev_queue_push_xmit(struct sk_buff *skb)
	39	{
8bd63cf1	40	if (!is_skb_forwardable(skb->dev, skb)) {
1da177e4	41	kfree_skb(skb);
f88de8de CG	42	} else {
f88de8de CG	43	skb_push(skb, ETH_HLEN);
a881e963	44	br_drop_fake_rtable(skb);
f88de8de	45	dev_queue_xmit(skb);
1da177e4 LT	46	}
	47
	48	return 0;
	49	}
34666d46	50	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4 LT	51
	52	int br_forward_finish(struct sk_buff *skb)
	53	{
713aefa3	54	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
9ef513be	55	br_dev_queue_push_xmit);
1da177e4	56
1da177e4	57	}
34666d46	58	EXPORT_SYMBOL_GPL(br_forward_finish);
1da177e4 LT	59
	60	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	61	{
78851988 VY	62	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	63	if (!skb)
	64	return;
	65
1da177e4	66	skb->dev = to->dev;
91d2c34a	67
e15c3c22	68	if (unlikely(netpoll_tx_running(to->br->dev))) {
f6367b46	69	if (!is_skb_forwardable(skb->dev, skb))
91d2c34a HX	70	kfree_skb(skb);
	71	else {
	72	skb_push(skb, ETH_HLEN);
	73	br_netpoll_send_skb(to, skb);
	74	}
	75	return;
	76	}
	77
713aefa3 JE	78	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
713aefa3 JE	79	br_forward_finish);
1da177e4 LT	80	}
	81
	82	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	83	{
	84	struct net_device *indev;
	85
4906f998 HX	86	if (skb_warn_if_lro(skb)) {
	87	kfree_skb(skb);
	88	return;
	89	}
	90
78851988 VY	91	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	92	if (!skb)
	93	return;
	94
1da177e4 LT	95	indev = skb->dev;
1da177e4 LT	96	skb->dev = to->dev;
35fc92a9	97	skb_forward_csum(skb);
1da177e4	98
713aefa3 JE	99	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
713aefa3 JE	100	br_forward_finish);
1da177e4 LT	101	}
	102
	103	/* called with rcu_read_lock */
	104	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	105	{
43598813	106	if (to && should_deliver(to, skb)) {
1da177e4 LT	107	__br_deliver(to, skb);
	108	return;
	109	}
	110
	111	kfree_skb(skb);
	112	}
523b929d	113	EXPORT_SYMBOL_GPL(br_deliver);
1da177e4 LT	114
1da177e4 LT	115	/* called with rcu_read_lock */
7f7708f0	116	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	117	{
4906f998	118	if (should_deliver(to, skb)) {
7f7708f0 MB	119	if (skb0)
	120	deliver_clone(to, skb, __br_forward);
	121	else
	122	__br_forward(to, skb);
1da177e4 LT	123	return;
	124	}
	125
7f7708f0 MB	126	if (!skb0)
7f7708f0 MB	127	kfree_skb(skb);
1da177e4 LT	128	}
1da177e4 LT	129
87faf3cc DM	130	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	131	struct sk_buff *skb,
025d89c2 HX	132	void (__packet_hook)(const struct net_bridge_port p,
	133	struct sk_buff *skb))
	134	{
fed396a5 HX	135	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
fed396a5 HX	136
025d89c2 HX	137	skb = skb_clone(skb, GFP_ATOMIC);
025d89c2 HX	138	if (!skb) {
025d89c2 HX	139	dev->stats.tx_dropped++;
	140	return -ENOMEM;
	141	}
	142
	143	__packet_hook(prev, skb);
	144	return 0;
	145	}
	146
	147	static struct net_bridge_port *maybe_deliver(
	148	struct net_bridge_port prev, struct net_bridge_port p,
	149	struct sk_buff *skb,
	150	void (__packet_hook)(const struct net_bridge_port p,
	151	struct sk_buff *skb))
	152	{
	153	int err;
	154
	155	if (!should_deliver(p, skb))
	156	return prev;
	157
	158	if (!prev)
	159	goto out;
	160
	161	err = deliver_clone(prev, skb, __packet_hook);
	162	if (err)
	163	return ERR_PTR(err);
	164
	165	out:
	166	return p;
	167	}
	168
1da177e4	169	/* called under bridge lock */
e081e1e3	170	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	171	struct sk_buff *skb0,
b33084be HX	172	void (__packet_hook)(const struct net_bridge_port p,
867a5943 VY	173	struct sk_buff *skb),
867a5943 VY	174	bool unicast)
1da177e4 LT	175	{
	176	struct net_bridge_port *p;
	177	struct net_bridge_port *prev;
	178
1da177e4 LT	179	prev = NULL;
	180
	181	list_for_each_entry_rcu(p, &br->port_list, list) {
867a5943 VY	182	/* Do not flood unicast traffic to ports that turn it off */
	183	if (unicast && !(p->flags & BR_FLOOD))
	184	continue;
95850116 KP	185
	186	/* Do not flood to ports that enable proxy ARP */
	187	if (p->flags & BR_PROXYARP)
	188	continue;
842a9ae0 JM	189	if ((p->flags & BR_PROXYARP_WIFI) &&
	190	BR_INPUT_SKB_CB(skb)->proxyarp_replied)
	191	continue;
95850116	192
025d89c2 HX	193	prev = maybe_deliver(prev, p, skb, __packet_hook);
	194	if (IS_ERR(prev))
	195	goto out;
1da177e4 LT	196	}
1da177e4 LT	197
b33084be HX	198	if (!prev)
	199	goto out;
	200
025d89c2 HX	201	if (skb0)
	202	deliver_clone(prev, skb, __packet_hook);
	203	else
	204	__packet_hook(prev, skb);
b33084be	205	return;
1da177e4	206
b33084be HX	207	out:
	208	if (!skb0)
	209	kfree_skb(skb);
1da177e4 LT	210	}
	211
	212
	213	/* called with rcu_read_lock */
867a5943	214	void br_flood_deliver(struct net_bridge br, struct sk_buff skb, bool unicast)
1da177e4	215	{
867a5943	216	br_flood(br, skb, NULL, __br_deliver, unicast);
1da177e4 LT	217	}
	218
	219	/* called under bridge lock */
b33084be	220	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
867a5943	221	struct sk_buff *skb2, bool unicast)
1da177e4	222	{
867a5943	223	br_flood(br, skb, skb2, __br_forward, unicast);
1da177e4	224	}
5cb5e947 HX	225
	226	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	227	/* called with rcu_read_lock */
	228	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	229	struct sk_buff skb, struct sk_buff skb0,
	230	void (*__packet_hook)(
	231	const struct net_bridge_port *p,
	232	struct sk_buff *skb))
	233	{
	234	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	235	struct net_bridge *br = netdev_priv(dev);
afe0159d	236	struct net_bridge_port *prev = NULL;
5cb5e947 HX	237	struct net_bridge_port_group *p;
	238	struct hlist_node *rp;
	239
e8051688	240	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	241	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	242	while (p \|\| rp) {
afe0159d	243	struct net_bridge_port port, lport, *rport;
afe0159d	244
5cb5e947 HX	245	lport = p ? p->port : NULL;
	246	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	247	NULL;
	248
	249	port = (unsigned long)lport > (unsigned long)rport ?
	250	lport : rport;
	251
	252	prev = maybe_deliver(prev, port, skb, __packet_hook);
	253	if (IS_ERR(prev))
	254	goto out;
	255
	256	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	257	p = rcu_dereference(p->next);
5cb5e947	258	if ((unsigned long)rport >= (unsigned long)port)
e8051688	259	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	260	}
	261
	262	if (!prev)
	263	goto out;
	264
	265	if (skb0)
	266	deliver_clone(prev, skb, __packet_hook);
	267	else
	268	__packet_hook(prev, skb);
	269	return;
	270
	271	out:
	272	if (!skb0)
	273	kfree_skb(skb);
	274	}
	275
	276	/* called with rcu_read_lock */
	277	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	278	struct sk_buff *skb)
	279	{
	280	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	281	}
	282
	283	/* called with rcu_read_lock */
	284	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	285	struct sk_buff skb, struct sk_buff skb2)
	286	{
	287	br_multicast_flood(mdst, skb, skb2, __br_forward);
	288	}
	289	#endif