[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 sock *sk, 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);
		skb_sender_cpu_clear(skb);
		dev_queue_xmit(skb);
	}

	return 0;
}
EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);

int br_forward_finish(struct sock *sk, struct sk_buff *skb)
{
	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, sk, 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, NULL, 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, NULL, 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	}
1da177e4 LT	37
7026b1dd	38	int br_dev_queue_push_xmit(struct sock sk, struct sk_buff skb)
1da177e4	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);
a7d35f9d	45	skb_sender_cpu_clear(skb);
f88de8de	46	dev_queue_xmit(skb);
1da177e4 LT	47	}
	48
	49	return 0;
	50	}
34666d46	51	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4	52
7026b1dd	53	int br_forward_finish(struct sock sk, struct sk_buff skb)
1da177e4	54	{
7026b1dd DM	55	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, sk, skb,
7026b1dd DM	56	NULL, skb->dev,
9ef513be	57	br_dev_queue_push_xmit);
1da177e4	58
1da177e4	59	}
34666d46	60	EXPORT_SYMBOL_GPL(br_forward_finish);
1da177e4 LT	61
	62	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	63	{
78851988 VY	64	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	65	if (!skb)
	66	return;
	67
1da177e4	68	skb->dev = to->dev;
91d2c34a	69
e15c3c22	70	if (unlikely(netpoll_tx_running(to->br->dev))) {
f6367b46	71	if (!is_skb_forwardable(skb->dev, skb))
91d2c34a HX	72	kfree_skb(skb);
	73	else {
	74	skb_push(skb, ETH_HLEN);
	75	br_netpoll_send_skb(to, skb);
	76	}
	77	return;
	78	}
	79
7026b1dd DM	80	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, NULL, skb,
7026b1dd DM	81	NULL, skb->dev,
713aefa3	82	br_forward_finish);
1da177e4 LT	83	}
	84
	85	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	86	{
	87	struct net_device *indev;
	88
4906f998 HX	89	if (skb_warn_if_lro(skb)) {
	90	kfree_skb(skb);
	91	return;
	92	}
	93
78851988 VY	94	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	95	if (!skb)
	96	return;
	97
1da177e4 LT	98	indev = skb->dev;
1da177e4 LT	99	skb->dev = to->dev;
35fc92a9	100	skb_forward_csum(skb);
1da177e4	101
7026b1dd DM	102	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, NULL, skb,
7026b1dd DM	103	indev, skb->dev,
713aefa3	104	br_forward_finish);
1da177e4 LT	105	}
	106
	107	/* called with rcu_read_lock */
	108	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	109	{
43598813	110	if (to && should_deliver(to, skb)) {
1da177e4 LT	111	__br_deliver(to, skb);
	112	return;
	113	}
	114
	115	kfree_skb(skb);
	116	}
523b929d	117	EXPORT_SYMBOL_GPL(br_deliver);
1da177e4 LT	118
1da177e4 LT	119	/* called with rcu_read_lock */
7f7708f0	120	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	121	{
4906f998	122	if (should_deliver(to, skb)) {
7f7708f0 MB	123	if (skb0)
	124	deliver_clone(to, skb, __br_forward);
	125	else
	126	__br_forward(to, skb);
1da177e4 LT	127	return;
	128	}
	129
7f7708f0 MB	130	if (!skb0)
7f7708f0 MB	131	kfree_skb(skb);
1da177e4 LT	132	}
1da177e4 LT	133
87faf3cc DM	134	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	135	struct sk_buff *skb,
025d89c2 HX	136	void (__packet_hook)(const struct net_bridge_port p,
	137	struct sk_buff *skb))
	138	{
fed396a5 HX	139	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
fed396a5 HX	140
025d89c2 HX	141	skb = skb_clone(skb, GFP_ATOMIC);
025d89c2 HX	142	if (!skb) {
025d89c2 HX	143	dev->stats.tx_dropped++;
	144	return -ENOMEM;
	145	}
	146
	147	__packet_hook(prev, skb);
	148	return 0;
	149	}
	150
	151	static struct net_bridge_port *maybe_deliver(
	152	struct net_bridge_port prev, struct net_bridge_port p,
	153	struct sk_buff *skb,
	154	void (__packet_hook)(const struct net_bridge_port p,
	155	struct sk_buff *skb))
	156	{
	157	int err;
	158
	159	if (!should_deliver(p, skb))
	160	return prev;
	161
	162	if (!prev)
	163	goto out;
	164
	165	err = deliver_clone(prev, skb, __packet_hook);
	166	if (err)
	167	return ERR_PTR(err);
	168
	169	out:
	170	return p;
	171	}
	172
1da177e4	173	/* called under bridge lock */
e081e1e3	174	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	175	struct sk_buff *skb0,
b33084be HX	176	void (__packet_hook)(const struct net_bridge_port p,
867a5943 VY	177	struct sk_buff *skb),
867a5943 VY	178	bool unicast)
1da177e4 LT	179	{
	180	struct net_bridge_port *p;
	181	struct net_bridge_port *prev;
	182
1da177e4 LT	183	prev = NULL;
	184
	185	list_for_each_entry_rcu(p, &br->port_list, list) {
867a5943 VY	186	/* Do not flood unicast traffic to ports that turn it off */
	187	if (unicast && !(p->flags & BR_FLOOD))
	188	continue;
95850116 KP	189
	190	/* Do not flood to ports that enable proxy ARP */
	191	if (p->flags & BR_PROXYARP)
	192	continue;
842a9ae0 JM	193	if ((p->flags & BR_PROXYARP_WIFI) &&
	194	BR_INPUT_SKB_CB(skb)->proxyarp_replied)
	195	continue;
95850116	196
025d89c2 HX	197	prev = maybe_deliver(prev, p, skb, __packet_hook);
	198	if (IS_ERR(prev))
	199	goto out;
1da177e4 LT	200	}
1da177e4 LT	201
b33084be HX	202	if (!prev)
	203	goto out;
	204
025d89c2 HX	205	if (skb0)
	206	deliver_clone(prev, skb, __packet_hook);
	207	else
	208	__packet_hook(prev, skb);
b33084be	209	return;
1da177e4	210
b33084be HX	211	out:
	212	if (!skb0)
	213	kfree_skb(skb);
1da177e4 LT	214	}
	215
	216
	217	/* called with rcu_read_lock */
867a5943	218	void br_flood_deliver(struct net_bridge br, struct sk_buff skb, bool unicast)
1da177e4	219	{
867a5943	220	br_flood(br, skb, NULL, __br_deliver, unicast);
1da177e4 LT	221	}
	222
	223	/* called under bridge lock */
b33084be	224	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
867a5943	225	struct sk_buff *skb2, bool unicast)
1da177e4	226	{
867a5943	227	br_flood(br, skb, skb2, __br_forward, unicast);
1da177e4	228	}
5cb5e947 HX	229
	230	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	231	/* called with rcu_read_lock */
	232	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	233	struct sk_buff skb, struct sk_buff skb0,
	234	void (*__packet_hook)(
	235	const struct net_bridge_port *p,
	236	struct sk_buff *skb))
	237	{
	238	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	239	struct net_bridge *br = netdev_priv(dev);
afe0159d	240	struct net_bridge_port *prev = NULL;
5cb5e947 HX	241	struct net_bridge_port_group *p;
	242	struct hlist_node *rp;
	243
e8051688	244	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	245	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	246	while (p \|\| rp) {
afe0159d	247	struct net_bridge_port port, lport, *rport;
afe0159d	248
5cb5e947 HX	249	lport = p ? p->port : NULL;
	250	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	251	NULL;
	252
	253	port = (unsigned long)lport > (unsigned long)rport ?
	254	lport : rport;
	255
	256	prev = maybe_deliver(prev, port, skb, __packet_hook);
	257	if (IS_ERR(prev))
	258	goto out;
	259
	260	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	261	p = rcu_dereference(p->next);
5cb5e947	262	if ((unsigned long)rport >= (unsigned long)port)
e8051688	263	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	264	}
	265
	266	if (!prev)
	267	goto out;
	268
	269	if (skb0)
	270	deliver_clone(prev, skb, __packet_hook);
	271	else
	272	__packet_hook(prev, skb);
	273	return;
	274
	275	out:
	276	if (!skb0)
	277	kfree_skb(skb);
	278	}
	279
	280	/* called with rcu_read_lock */
	281	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	282	struct sk_buff *skb)
	283	{
	284	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	285	}
	286
	287	/* called with rcu_read_lock */
	288	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	289	struct sk_buff skb, struct sk_buff skb2)
	290	{
	291	br_multicast_flood(mdst, skb, skb2, __br_forward);
	292	}
	293	#endif