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

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