[mirror_ubuntu-artful-kernel.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))
		goto drop;

	skb_push(skb, ETH_HLEN);
	br_drop_fake_rtable(skb);
	skb_sender_cpu_clear(skb);

	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	    (skb->protocol == htons(ETH_P_8021Q) ||
	     skb->protocol == htons(ETH_P_8021AD))) {
		int depth;

		if (!__vlan_get_protocol(skb, skb->protocol, &depth))
			goto drop;

		skb_set_network_header(skb, depth);
	}

	dev_queue_xmit(skb);

	return 0;

drop:
	kfree_skb(skb);
	return 0;
}
EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);

int br_forward_finish(struct sock *sk, struct sk_buff *skb)
{
	struct net *net = dev_net(skb->dev);
	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
		       net, 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,
		dev_net(skb->dev), 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,
		dev_net(indev), 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	{
df356d5e TM	40	if (!is_skb_forwardable(skb->dev, skb))
	41	goto drop;
	42
	43	skb_push(skb, ETH_HLEN);
	44	br_drop_fake_rtable(skb);
	45	skb_sender_cpu_clear(skb);
	46
	47	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	48	(skb->protocol == htons(ETH_P_8021Q) \|\|
	49	skb->protocol == htons(ETH_P_8021AD))) {
	50	int depth;
	51
	52	if (!__vlan_get_protocol(skb, skb->protocol, &depth))
	53	goto drop;
	54
	55	skb_set_network_header(skb, depth);
1da177e4 LT	56	}
1da177e4 LT	57
df356d5e TM	58	dev_queue_xmit(skb);
	59
	60	return 0;
	61
	62	drop:
	63	kfree_skb(skb);
1da177e4 LT	64	return 0;
1da177e4 LT	65	}
34666d46	66	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4	67
7026b1dd	68	int br_forward_finish(struct sock sk, struct sk_buff skb)
1da177e4	69	{
29a26a56 EB	70	struct net *net = dev_net(skb->dev);
	71	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
	72	net, sk, skb, NULL, skb->dev,
9ef513be	73	br_dev_queue_push_xmit);
1da177e4	74
1da177e4	75	}
34666d46	76	EXPORT_SYMBOL_GPL(br_forward_finish);
1da177e4 LT	77
	78	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	79	{
78851988 VY	80	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	81	if (!skb)
	82	return;
	83
1da177e4	84	skb->dev = to->dev;
91d2c34a	85
e15c3c22	86	if (unlikely(netpoll_tx_running(to->br->dev))) {
f6367b46	87	if (!is_skb_forwardable(skb->dev, skb))
91d2c34a HX	88	kfree_skb(skb);
	89	else {
	90	skb_push(skb, ETH_HLEN);
	91	br_netpoll_send_skb(to, skb);
	92	}
	93	return;
	94	}
	95
29a26a56 EB	96	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
29a26a56 EB	97	dev_net(skb->dev), NULL, skb,NULL, skb->dev,
713aefa3	98	br_forward_finish);
1da177e4 LT	99	}
	100
	101	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	102	{
	103	struct net_device *indev;
	104
4906f998 HX	105	if (skb_warn_if_lro(skb)) {
	106	kfree_skb(skb);
	107	return;
	108	}
	109
78851988 VY	110	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	111	if (!skb)
	112	return;
	113
1da177e4 LT	114	indev = skb->dev;
1da177e4 LT	115	skb->dev = to->dev;
35fc92a9	116	skb_forward_csum(skb);
1da177e4	117
29a26a56 EB	118	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD,
29a26a56 EB	119	dev_net(indev), NULL, skb, indev, skb->dev,
713aefa3	120	br_forward_finish);
1da177e4 LT	121	}
	122
	123	/* called with rcu_read_lock */
	124	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	125	{
43598813	126	if (to && should_deliver(to, skb)) {
1da177e4 LT	127	__br_deliver(to, skb);
	128	return;
	129	}
	130
	131	kfree_skb(skb);
	132	}
523b929d	133	EXPORT_SYMBOL_GPL(br_deliver);
1da177e4 LT	134
1da177e4 LT	135	/* called with rcu_read_lock */
7f7708f0	136	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	137	{
4906f998	138	if (should_deliver(to, skb)) {
7f7708f0 MB	139	if (skb0)
	140	deliver_clone(to, skb, __br_forward);
	141	else
	142	__br_forward(to, skb);
1da177e4 LT	143	return;
	144	}
	145
7f7708f0 MB	146	if (!skb0)
7f7708f0 MB	147	kfree_skb(skb);
1da177e4 LT	148	}
1da177e4 LT	149
87faf3cc DM	150	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	151	struct sk_buff *skb,
025d89c2 HX	152	void (__packet_hook)(const struct net_bridge_port p,
	153	struct sk_buff *skb))
	154	{
fed396a5 HX	155	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
fed396a5 HX	156
025d89c2 HX	157	skb = skb_clone(skb, GFP_ATOMIC);
025d89c2 HX	158	if (!skb) {
025d89c2 HX	159	dev->stats.tx_dropped++;
	160	return -ENOMEM;
	161	}
	162
	163	__packet_hook(prev, skb);
	164	return 0;
	165	}
	166
	167	static struct net_bridge_port *maybe_deliver(
	168	struct net_bridge_port prev, struct net_bridge_port p,
	169	struct sk_buff *skb,
	170	void (__packet_hook)(const struct net_bridge_port p,
	171	struct sk_buff *skb))
	172	{
	173	int err;
	174
	175	if (!should_deliver(p, skb))
	176	return prev;
	177
	178	if (!prev)
	179	goto out;
	180
	181	err = deliver_clone(prev, skb, __packet_hook);
	182	if (err)
	183	return ERR_PTR(err);
	184
	185	out:
	186	return p;
	187	}
	188
1da177e4	189	/* called under bridge lock */
e081e1e3	190	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	191	struct sk_buff *skb0,
b33084be HX	192	void (__packet_hook)(const struct net_bridge_port p,
867a5943 VY	193	struct sk_buff *skb),
867a5943 VY	194	bool unicast)
1da177e4 LT	195	{
	196	struct net_bridge_port *p;
	197	struct net_bridge_port *prev;
	198
1da177e4 LT	199	prev = NULL;
	200
	201	list_for_each_entry_rcu(p, &br->port_list, list) {
867a5943 VY	202	/* Do not flood unicast traffic to ports that turn it off */
	203	if (unicast && !(p->flags & BR_FLOOD))
	204	continue;
95850116 KP	205
	206	/* Do not flood to ports that enable proxy ARP */
	207	if (p->flags & BR_PROXYARP)
	208	continue;
842a9ae0 JM	209	if ((p->flags & BR_PROXYARP_WIFI) &&
	210	BR_INPUT_SKB_CB(skb)->proxyarp_replied)
	211	continue;
95850116	212
025d89c2 HX	213	prev = maybe_deliver(prev, p, skb, __packet_hook);
	214	if (IS_ERR(prev))
	215	goto out;
1da177e4 LT	216	}
1da177e4 LT	217
b33084be HX	218	if (!prev)
	219	goto out;
	220
025d89c2 HX	221	if (skb0)
	222	deliver_clone(prev, skb, __packet_hook);
	223	else
	224	__packet_hook(prev, skb);
b33084be	225	return;
1da177e4	226
b33084be HX	227	out:
	228	if (!skb0)
	229	kfree_skb(skb);
1da177e4 LT	230	}
	231
	232
	233	/* called with rcu_read_lock */
867a5943	234	void br_flood_deliver(struct net_bridge br, struct sk_buff skb, bool unicast)
1da177e4	235	{
867a5943	236	br_flood(br, skb, NULL, __br_deliver, unicast);
1da177e4 LT	237	}
	238
	239	/* called under bridge lock */
b33084be	240	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
867a5943	241	struct sk_buff *skb2, bool unicast)
1da177e4	242	{
867a5943	243	br_flood(br, skb, skb2, __br_forward, unicast);
1da177e4	244	}
5cb5e947 HX	245
	246	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	247	/* called with rcu_read_lock */
	248	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	249	struct sk_buff skb, struct sk_buff skb0,
	250	void (*__packet_hook)(
	251	const struct net_bridge_port *p,
	252	struct sk_buff *skb))
	253	{
	254	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	255	struct net_bridge *br = netdev_priv(dev);
afe0159d	256	struct net_bridge_port *prev = NULL;
5cb5e947 HX	257	struct net_bridge_port_group *p;
	258	struct hlist_node *rp;
	259
e8051688	260	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	261	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	262	while (p \|\| rp) {
afe0159d	263	struct net_bridge_port port, lport, *rport;
afe0159d	264
5cb5e947 HX	265	lport = p ? p->port : NULL;
	266	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	267	NULL;
	268
	269	port = (unsigned long)lport > (unsigned long)rport ?
	270	lport : rport;
	271
	272	prev = maybe_deliver(prev, port, skb, __packet_hook);
	273	if (IS_ERR(prev))
	274	goto out;
	275
	276	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	277	p = rcu_dereference(p->next);
5cb5e947	278	if ((unsigned long)rport >= (unsigned long)port)
e8051688	279	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	280	}
	281
	282	if (!prev)
	283	goto out;
	284
	285	if (skb0)
	286	deliver_clone(prev, skb, __packet_hook);
	287	else
	288	__packet_hook(prev, skb);
	289	return;
	290
	291	out:
	292	if (!skb0)
	293	kfree_skb(skb);
	294	}
	295
	296	/* called with rcu_read_lock */
	297	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	298	struct sk_buff *skb)
	299	{
	300	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	301	}
	302
	303	/* called with rcu_read_lock */
	304	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	305	struct sk_buff skb, struct sk_buff skb2)
	306	{
	307	br_multicast_flood(mdst, skb, skb2, __br_forward);
	308	}
	309	#endif