[mirror_ubuntu-zesty-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)
{
	struct net_bridge_vlan_group *vg;

	vg = nbp_vlan_group_rcu(p);
	return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
		br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING;
}

int br_dev_queue_push_xmit(struct net *net, 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 net *net, struct sock *sk, struct sk_buff *skb)
{
	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)
{
	struct net_bridge_vlan_group *vg;

	vg = nbp_vlan_group_rcu(to);
	skb = br_handle_vlan(to->br, vg, 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_bridge_vlan_group *vg;
	struct net_device *indev;

	if (skb_warn_if_lro(skb)) {
		kfree_skb(skb);
		return;
	}

	vg = nbp_vlan_group_rcu(to);
	skb = br_handle_vlan(to->br, vg, 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 (to && 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	{
2594e906 NA	33	struct net_bridge_vlan_group *vg;
2594e906 NA	34
907b1e6e	35	vg = nbp_vlan_group_rcu(p);
a97bfc1d	36	return ((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
2594e906	37	br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING;
1da177e4 LT	38	}
1da177e4 LT	39
0c4b51f0	40	int br_dev_queue_push_xmit(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	41	{
df356d5e TM	42	if (!is_skb_forwardable(skb->dev, skb))
	43	goto drop;
	44
	45	skb_push(skb, ETH_HLEN);
	46	br_drop_fake_rtable(skb);
	47	skb_sender_cpu_clear(skb);
	48
	49	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	50	(skb->protocol == htons(ETH_P_8021Q) \|\|
	51	skb->protocol == htons(ETH_P_8021AD))) {
	52	int depth;
	53
	54	if (!__vlan_get_protocol(skb, skb->protocol, &depth))
	55	goto drop;
	56
	57	skb_set_network_header(skb, depth);
1da177e4 LT	58	}
1da177e4 LT	59
df356d5e TM	60	dev_queue_xmit(skb);
	61
	62	return 0;
	63
	64	drop:
	65	kfree_skb(skb);
1da177e4 LT	66	return 0;
1da177e4 LT	67	}
34666d46	68	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4	69
0c4b51f0	70	int br_forward_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	71	{
29a26a56 EB	72	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
29a26a56 EB	73	net, sk, skb, NULL, skb->dev,
9ef513be	74	br_dev_queue_push_xmit);
1da177e4	75
1da177e4	76	}
34666d46	77	EXPORT_SYMBOL_GPL(br_forward_finish);
1da177e4 LT	78
	79	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	80	{
2594e906 NA	81	struct net_bridge_vlan_group *vg;
2594e906 NA	82
907b1e6e	83	vg = nbp_vlan_group_rcu(to);
2594e906	84	skb = br_handle_vlan(to->br, vg, skb);
78851988 VY	85	if (!skb)
	86	return;
	87
1da177e4	88	skb->dev = to->dev;
91d2c34a	89
e15c3c22	90	if (unlikely(netpoll_tx_running(to->br->dev))) {
f6367b46	91	if (!is_skb_forwardable(skb->dev, skb))
91d2c34a HX	92	kfree_skb(skb);
	93	else {
	94	skb_push(skb, ETH_HLEN);
	95	br_netpoll_send_skb(to, skb);
	96	}
	97	return;
	98	}
	99
29a26a56 EB	100	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
29a26a56 EB	101	dev_net(skb->dev), NULL, skb,NULL, skb->dev,
713aefa3	102	br_forward_finish);
1da177e4 LT	103	}
	104
	105	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	106	{
2594e906	107	struct net_bridge_vlan_group *vg;
1da177e4 LT	108	struct net_device *indev;
1da177e4 LT	109
4906f998 HX	110	if (skb_warn_if_lro(skb)) {
	111	kfree_skb(skb);
	112	return;
	113	}
	114
907b1e6e	115	vg = nbp_vlan_group_rcu(to);
2594e906	116	skb = br_handle_vlan(to->br, vg, skb);
78851988 VY	117	if (!skb)
	118	return;
	119
1da177e4 LT	120	indev = skb->dev;
1da177e4 LT	121	skb->dev = to->dev;
35fc92a9	122	skb_forward_csum(skb);
1da177e4	123
29a26a56 EB	124	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD,
29a26a56 EB	125	dev_net(indev), NULL, skb, indev, skb->dev,
713aefa3	126	br_forward_finish);
1da177e4 LT	127	}
	128
	129	/* called with rcu_read_lock */
	130	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	131	{
43598813	132	if (to && should_deliver(to, skb)) {
1da177e4 LT	133	__br_deliver(to, skb);
	134	return;
	135	}
	136
	137	kfree_skb(skb);
	138	}
523b929d	139	EXPORT_SYMBOL_GPL(br_deliver);
1da177e4 LT	140
1da177e4 LT	141	/* called with rcu_read_lock */
7f7708f0	142	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	143	{
b7af1472	144	if (to && should_deliver(to, skb)) {
7f7708f0 MB	145	if (skb0)
	146	deliver_clone(to, skb, __br_forward);
	147	else
	148	__br_forward(to, skb);
1da177e4 LT	149	return;
	150	}
	151
7f7708f0 MB	152	if (!skb0)
7f7708f0 MB	153	kfree_skb(skb);
1da177e4 LT	154	}
1da177e4 LT	155
87faf3cc DM	156	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	157	struct sk_buff *skb,
025d89c2 HX	158	void (__packet_hook)(const struct net_bridge_port p,
	159	struct sk_buff *skb))
	160	{
fed396a5 HX	161	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
fed396a5 HX	162
025d89c2 HX	163	skb = skb_clone(skb, GFP_ATOMIC);
025d89c2 HX	164	if (!skb) {
025d89c2 HX	165	dev->stats.tx_dropped++;
	166	return -ENOMEM;
	167	}
	168
	169	__packet_hook(prev, skb);
	170	return 0;
	171	}
	172
	173	static struct net_bridge_port *maybe_deliver(
	174	struct net_bridge_port prev, struct net_bridge_port p,
	175	struct sk_buff *skb,
	176	void (__packet_hook)(const struct net_bridge_port p,
	177	struct sk_buff *skb))
	178	{
	179	int err;
	180
	181	if (!should_deliver(p, skb))
	182	return prev;
	183
	184	if (!prev)
	185	goto out;
	186
	187	err = deliver_clone(prev, skb, __packet_hook);
	188	if (err)
	189	return ERR_PTR(err);
	190
	191	out:
	192	return p;
	193	}
	194
1da177e4	195	/* called under bridge lock */
e081e1e3	196	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	197	struct sk_buff *skb0,
b33084be HX	198	void (__packet_hook)(const struct net_bridge_port p,
867a5943 VY	199	struct sk_buff *skb),
867a5943 VY	200	bool unicast)
1da177e4 LT	201	{
	202	struct net_bridge_port *p;
	203	struct net_bridge_port *prev;
	204
1da177e4 LT	205	prev = NULL;
	206
	207	list_for_each_entry_rcu(p, &br->port_list, list) {
867a5943 VY	208	/* Do not flood unicast traffic to ports that turn it off */
	209	if (unicast && !(p->flags & BR_FLOOD))
	210	continue;
95850116 KP	211
	212	/* Do not flood to ports that enable proxy ARP */
	213	if (p->flags & BR_PROXYARP)
	214	continue;
842a9ae0 JM	215	if ((p->flags & BR_PROXYARP_WIFI) &&
	216	BR_INPUT_SKB_CB(skb)->proxyarp_replied)
	217	continue;
95850116	218
025d89c2 HX	219	prev = maybe_deliver(prev, p, skb, __packet_hook);
	220	if (IS_ERR(prev))
	221	goto out;
1da177e4 LT	222	}
1da177e4 LT	223
b33084be HX	224	if (!prev)
	225	goto out;
	226
025d89c2 HX	227	if (skb0)
	228	deliver_clone(prev, skb, __packet_hook);
	229	else
	230	__packet_hook(prev, skb);
b33084be	231	return;
1da177e4	232
b33084be HX	233	out:
	234	if (!skb0)
	235	kfree_skb(skb);
1da177e4 LT	236	}
	237
	238
	239	/* called with rcu_read_lock */
867a5943	240	void br_flood_deliver(struct net_bridge br, struct sk_buff skb, bool unicast)
1da177e4	241	{
867a5943	242	br_flood(br, skb, NULL, __br_deliver, unicast);
1da177e4 LT	243	}
	244
	245	/* called under bridge lock */
b33084be	246	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
867a5943	247	struct sk_buff *skb2, bool unicast)
1da177e4	248	{
867a5943	249	br_flood(br, skb, skb2, __br_forward, unicast);
1da177e4	250	}
5cb5e947 HX	251
	252	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	253	/* called with rcu_read_lock */
	254	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	255	struct sk_buff skb, struct sk_buff skb0,
	256	void (*__packet_hook)(
	257	const struct net_bridge_port *p,
	258	struct sk_buff *skb))
	259	{
	260	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	261	struct net_bridge *br = netdev_priv(dev);
afe0159d	262	struct net_bridge_port *prev = NULL;
5cb5e947 HX	263	struct net_bridge_port_group *p;
	264	struct hlist_node *rp;
	265
e8051688	266	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	267	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	268	while (p \|\| rp) {
afe0159d	269	struct net_bridge_port port, lport, *rport;
afe0159d	270
5cb5e947 HX	271	lport = p ? p->port : NULL;
	272	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	273	NULL;
	274
	275	port = (unsigned long)lport > (unsigned long)rport ?
	276	lport : rport;
	277
	278	prev = maybe_deliver(prev, port, skb, __packet_hook);
	279	if (IS_ERR(prev))
	280	goto out;
	281
	282	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	283	p = rcu_dereference(p->next);
5cb5e947	284	if ((unsigned long)rport >= (unsigned long)port)
e8051688	285	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	286	}
	287
	288	if (!prev)
	289	goto out;
	290
	291	if (skb0)
	292	deliver_clone(prev, skb, __packet_hook);
	293	else
	294	__packet_hook(prev, skb);
	295	return;
	296
	297	out:
	298	if (!skb0)
	299	kfree_skb(skb);
	300	}
	301
	302	/* called with rcu_read_lock */
	303	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	304	struct sk_buff *skb)
	305	{
	306	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	307	}
	308
	309	/* called with rcu_read_lock */
	310	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	311	struct sk_buff skb, struct sk_buff skb2)
	312	{
	313	br_multicast_flood(mdst, skb, skb2, __br_forward);
	314	}
	315	#endif