[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)
{
	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);

	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,
		bool local_rcv)
{
	if (to && should_deliver(to, skb)) {
		if (local_rcv)
			deliver_clone(to, skb, __br_forward);
		else
			__br_forward(to, skb);
		return;
	}

	if (!local_rcv)
		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,
		     void (*__packet_hook)(const struct net_bridge_port *p,
					   struct sk_buff *skb),
		     bool local_rcv, bool unicast)
{
	u8 igmp_type = br_multicast_igmp_type(skb);
	struct net_bridge_port *prev;
	struct net_bridge_port *p;

	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 == p)
			br_multicast_count(p->br, p, skb, igmp_type,
					   BR_MCAST_DIR_TX);
	}

	if (!prev)
		goto out;

	if (local_rcv)
		deliver_clone(prev, skb, __packet_hook);
	else
		__packet_hook(prev, skb);
	return;

out:
	if (!local_rcv)
		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, __br_deliver, false, unicast);
}

/* called under bridge lock */
void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
		      bool local_rcv, bool unicast)
{
	br_flood(br, skb, __br_forward, local_rcv, 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,
			       void (*__packet_hook)(
					const struct net_bridge_port *p,
					struct sk_buff *skb),
			       bool local_rcv)
{
	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	u8 igmp_type = br_multicast_igmp_type(skb);
	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 (prev == port)
			br_multicast_count(port->br, port, skb, igmp_type,
					   BR_MCAST_DIR_TX);

		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 (local_rcv)
		deliver_clone(prev, skb, __packet_hook);
	else
		__packet_hook(prev, skb);
	return;

out:
	if (!local_rcv)
		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, __br_deliver, false);
}

/* called with rcu_read_lock */
void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
			  struct sk_buff *skb, bool local_rcv)
{
	br_multicast_flood(mdst, skb, __br_forward, local_rcv);
}
#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);
df356d5e TM	47
	48	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	49	(skb->protocol == htons(ETH_P_8021Q) \|\|
	50	skb->protocol == htons(ETH_P_8021AD))) {
	51	int depth;
	52
	53	if (!__vlan_get_protocol(skb, skb->protocol, &depth))
	54	goto drop;
	55
	56	skb_set_network_header(skb, depth);
1da177e4 LT	57	}
1da177e4 LT	58
df356d5e TM	59	dev_queue_xmit(skb);
	60
	61	return 0;
	62
	63	drop:
	64	kfree_skb(skb);
1da177e4 LT	65	return 0;
1da177e4 LT	66	}
34666d46	67	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4	68
0c4b51f0	69	int br_forward_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	70	{
29a26a56 EB	71	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
29a26a56 EB	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	{
2594e906 NA	80	struct net_bridge_vlan_group *vg;
2594e906 NA	81
907b1e6e	82	vg = nbp_vlan_group_rcu(to);
2594e906	83	skb = br_handle_vlan(to->br, vg, skb);
78851988 VY	84	if (!skb)
	85	return;
	86
1da177e4	87	skb->dev = to->dev;
91d2c34a	88
e15c3c22	89	if (unlikely(netpoll_tx_running(to->br->dev))) {
f6367b46	90	if (!is_skb_forwardable(skb->dev, skb))
91d2c34a HX	91	kfree_skb(skb);
	92	else {
	93	skb_push(skb, ETH_HLEN);
	94	br_netpoll_send_skb(to, skb);
	95	}
	96	return;
	97	}
	98
29a26a56 EB	99	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
29a26a56 EB	100	dev_net(skb->dev), NULL, skb,NULL, skb->dev,
713aefa3	101	br_forward_finish);
1da177e4 LT	102	}
	103
	104	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	105	{
2594e906	106	struct net_bridge_vlan_group *vg;
1da177e4 LT	107	struct net_device *indev;
1da177e4 LT	108
4906f998 HX	109	if (skb_warn_if_lro(skb)) {
	110	kfree_skb(skb);
	111	return;
	112	}
	113
907b1e6e	114	vg = nbp_vlan_group_rcu(to);
2594e906	115	skb = br_handle_vlan(to->br, vg, skb);
78851988 VY	116	if (!skb)
	117	return;
	118
1da177e4 LT	119	indev = skb->dev;
1da177e4 LT	120	skb->dev = to->dev;
35fc92a9	121	skb_forward_csum(skb);
1da177e4	122
29a26a56 EB	123	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD,
29a26a56 EB	124	dev_net(indev), NULL, skb, indev, skb->dev,
713aefa3	125	br_forward_finish);
1da177e4 LT	126	}
	127
	128	/* called with rcu_read_lock */
	129	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	130	{
43598813	131	if (to && should_deliver(to, skb)) {
1da177e4 LT	132	__br_deliver(to, skb);
	133	return;
	134	}
	135
	136	kfree_skb(skb);
	137	}
523b929d	138	EXPORT_SYMBOL_GPL(br_deliver);
1da177e4 LT	139
1da177e4 LT	140	/* called with rcu_read_lock */
b35c5f63 NA	141	void br_forward(const struct net_bridge_port to, struct sk_buff skb,
b35c5f63 NA	142	bool local_rcv)
1da177e4	143	{
b7af1472	144	if (to && should_deliver(to, skb)) {
b35c5f63	145	if (local_rcv)
7f7708f0 MB	146	deliver_clone(to, skb, __br_forward);
	147	else
	148	__br_forward(to, skb);
1da177e4 LT	149	return;
	150	}
	151
b35c5f63	152	if (!local_rcv)
7f7708f0	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	197	void (__packet_hook)(const struct net_bridge_port p,
867a5943	198	struct sk_buff *skb),
b35c5f63	199	bool local_rcv, bool unicast)
1da177e4	200	{
1080ab95	201	u8 igmp_type = br_multicast_igmp_type(skb);
1da177e4	202	struct net_bridge_port *prev;
1080ab95	203	struct net_bridge_port *p;
1da177e4	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;
1080ab95	222	if (prev == p)
a65056ec	223	br_multicast_count(p->br, p, skb, igmp_type,
1080ab95	224	BR_MCAST_DIR_TX);
1da177e4 LT	225	}
1da177e4 LT	226
b33084be HX	227	if (!prev)
	228	goto out;
	229
b35c5f63	230	if (local_rcv)
025d89c2 HX	231	deliver_clone(prev, skb, __packet_hook);
	232	else
	233	__packet_hook(prev, skb);
b33084be	234	return;
1da177e4	235
b33084be	236	out:
b35c5f63	237	if (!local_rcv)
b33084be	238	kfree_skb(skb);
1da177e4 LT	239	}
	240
	241
	242	/* called with rcu_read_lock */
867a5943	243	void br_flood_deliver(struct net_bridge br, struct sk_buff skb, bool unicast)
1da177e4	244	{
b35c5f63	245	br_flood(br, skb, __br_deliver, false, unicast);
1da177e4 LT	246	}
	247
	248	/* called under bridge lock */
b33084be	249	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
b35c5f63	250	bool local_rcv, bool unicast)
1da177e4	251	{
b35c5f63	252	br_flood(br, skb, __br_forward, local_rcv, unicast);
1da177e4	253	}
5cb5e947 HX	254
	255	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	256	/* called with rcu_read_lock */
	257	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
b35c5f63	258	struct sk_buff *skb,
5cb5e947 HX	259	void (*__packet_hook)(
5cb5e947 HX	260	const struct net_bridge_port *p,
b35c5f63 NA	261	struct sk_buff *skb),
b35c5f63 NA	262	bool local_rcv)
5cb5e947 HX	263	{
5cb5e947 HX	264	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
1080ab95	265	u8 igmp_type = br_multicast_igmp_type(skb);
5cb5e947	266	struct net_bridge *br = netdev_priv(dev);
afe0159d	267	struct net_bridge_port *prev = NULL;
5cb5e947 HX	268	struct net_bridge_port_group *p;
	269	struct hlist_node *rp;
	270
e8051688	271	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	272	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	273	while (p \|\| rp) {
afe0159d	274	struct net_bridge_port port, lport, *rport;
afe0159d	275
5cb5e947 HX	276	lport = p ? p->port : NULL;
	277	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	278	NULL;
	279
	280	port = (unsigned long)lport > (unsigned long)rport ?
	281	lport : rport;
	282
	283	prev = maybe_deliver(prev, port, skb, __packet_hook);
	284	if (IS_ERR(prev))
	285	goto out;
1080ab95	286	if (prev == port)
a65056ec	287	br_multicast_count(port->br, port, skb, igmp_type,
1080ab95	288	BR_MCAST_DIR_TX);
5cb5e947 HX	289
5cb5e947 HX	290	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	291	p = rcu_dereference(p->next);
5cb5e947	292	if ((unsigned long)rport >= (unsigned long)port)
e8051688	293	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	294	}
	295
	296	if (!prev)
	297	goto out;
	298
b35c5f63	299	if (local_rcv)
5cb5e947 HX	300	deliver_clone(prev, skb, __packet_hook);
	301	else
	302	__packet_hook(prev, skb);
	303	return;
	304
	305	out:
b35c5f63	306	if (!local_rcv)
5cb5e947 HX	307	kfree_skb(skb);
	308	}
	309
	310	/* called with rcu_read_lock */
	311	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	312	struct sk_buff *skb)
	313	{
b35c5f63	314	br_multicast_flood(mdst, skb, __br_deliver, false);
5cb5e947 HX	315	}
	316
	317	/* called with rcu_read_lock */
	318	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
b35c5f63	319	struct sk_buff *skb, bool local_rcv)
5cb5e947	320	{
b35c5f63	321	br_multicast_flood(mdst, skb, __br_forward, local_rcv);
5cb5e947 HX	322	}
5cb5e947 HX	323	#endif