[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/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)
{
	/* ip_fragment doesn't copy the MAC header */
	if (nf_bridge_maybe_copy_header(skb) ||
	    !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;

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