[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"

/* 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_forward(const struct net_bridge_port *to,
			 struct sk_buff *skb, bool local_orig)
{
	struct net_bridge_vlan_group *vg;
	struct net_device *indev;
	struct net *net;
	int br_hook;

	vg = nbp_vlan_group_rcu(to);
	skb = br_handle_vlan(to->br, vg, skb);
	if (!skb)
		return;

	indev = skb->dev;
	skb->dev = to->dev;
	if (!local_orig) {
		if (skb_warn_if_lro(skb)) {
			kfree_skb(skb);
			return;
		}
		br_hook = NF_BR_FORWARD;
		skb_forward_csum(skb);
		net = dev_net(indev);
	} else {
		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;
		}
		br_hook = NF_BR_LOCAL_OUT;
		net = dev_net(skb->dev);
		indev = NULL;
	}

	NF_HOOK(NFPROTO_BRIDGE, br_hook,
		net, NULL, skb, indev, skb->dev,
		br_forward_finish);
}

static int deliver_clone(const struct net_bridge_port *prev,
			 struct sk_buff *skb, bool local_orig)
{
	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;

	skb = skb_clone(skb, GFP_ATOMIC);
	if (!skb) {
		dev->stats.tx_dropped++;
		return -ENOMEM;
	}

	__br_forward(prev, skb, local_orig);
	return 0;
}

/**
 * br_forward - forward a packet to a specific port
 * @to: destination port
 * @skb: packet being forwarded
 * @local_rcv: packet will be received locally after forwarding
 * @local_orig: packet is locally originated
 *
 * Should be called with rcu_read_lock.
 */
void br_forward(const struct net_bridge_port *to,
		struct sk_buff *skb, bool local_rcv, bool local_orig)
{
	if (to && should_deliver(to, skb)) {
		if (local_rcv)
			deliver_clone(to, skb, local_orig);
		else
			__br_forward(to, skb, local_orig);
		return;
	}

	if (!local_rcv)
		kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(br_forward);

static struct net_bridge_port *maybe_deliver(
	struct net_bridge_port *prev, struct net_bridge_port *p,
	struct sk_buff *skb, bool local_orig)
{
	int err;

	if (!should_deliver(p, skb))
		return prev;

	if (!prev)
		goto out;

	err = deliver_clone(prev, skb, local_orig);
	if (err)
		return ERR_PTR(err);

out:
	return p;
}

/* called under rcu_read_lock */
void br_flood(struct net_bridge *br, struct sk_buff *skb,
	      bool unicast, bool local_rcv, bool local_orig)
{
	u8 igmp_type = br_multicast_igmp_type(skb);
	struct net_bridge_port *prev = NULL;
	struct net_bridge_port *p;

	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, local_orig);
		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, local_orig);
	else
		__br_forward(prev, skb, local_orig);
	return;

out:
	if (!local_rcv)
		kfree_skb(skb);
}

#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
/* called with rcu_read_lock */
void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
			struct sk_buff *skb,
			bool local_rcv, bool local_orig)
{
	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, local_orig);
		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, local_orig);
	else
		__br_forward(prev, skb, local_orig);
	return;

out:
	if (!local_rcv)
		kfree_skb(skb);
}
#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
1a81a2e0	24	/* Don't forward packets to originating port or forwarding disabled */
9d6f229f	25	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	26	const struct sk_buff *skb)
1da177e4 LT	27	{
2594e906 NA	28	struct net_bridge_vlan_group *vg;
2594e906 NA	29
907b1e6e	30	vg = nbp_vlan_group_rcu(p);
a97bfc1d	31	return ((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
2594e906	32	br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING;
1da177e4 LT	33	}
1da177e4 LT	34
0c4b51f0	35	int br_dev_queue_push_xmit(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	36	{
df356d5e TM	37	if (!is_skb_forwardable(skb->dev, skb))
	38	goto drop;
	39
	40	skb_push(skb, ETH_HLEN);
	41	br_drop_fake_rtable(skb);
df356d5e TM	42
	43	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	44	(skb->protocol == htons(ETH_P_8021Q) \|\|
	45	skb->protocol == htons(ETH_P_8021AD))) {
	46	int depth;
	47
	48	if (!__vlan_get_protocol(skb, skb->protocol, &depth))
	49	goto drop;
	50
	51	skb_set_network_header(skb, depth);
1da177e4 LT	52	}
1da177e4 LT	53
df356d5e TM	54	dev_queue_xmit(skb);
	55
	56	return 0;
	57
	58	drop:
	59	kfree_skb(skb);
1da177e4 LT	60	return 0;
1da177e4 LT	61	}
34666d46	62	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4	63
0c4b51f0	64	int br_forward_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	65	{
29a26a56 EB	66	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
29a26a56 EB	67	net, sk, skb, NULL, skb->dev,
9ef513be	68	br_dev_queue_push_xmit);
1da177e4	69
1da177e4	70	}
34666d46	71	EXPORT_SYMBOL_GPL(br_forward_finish);
1da177e4	72
37b090e6 NA	73	static void __br_forward(const struct net_bridge_port *to,
37b090e6 NA	74	struct sk_buff *skb, bool local_orig)
1da177e4	75	{
2594e906	76	struct net_bridge_vlan_group *vg;
37b090e6 NA	77	struct net_device *indev;
	78	struct net *net;
	79	int br_hook;
2594e906	80
907b1e6e	81	vg = nbp_vlan_group_rcu(to);
2594e906	82	skb = br_handle_vlan(to->br, vg, skb);
78851988 VY	83	if (!skb)
	84	return;
	85
37b090e6	86	indev = skb->dev;
1da177e4	87	skb->dev = to->dev;
37b090e6 NA	88	if (!local_orig) {
37b090e6 NA	89	if (skb_warn_if_lro(skb)) {
91d2c34a	90	kfree_skb(skb);
37b090e6	91	return;
91d2c34a	92	}
37b090e6 NA	93	br_hook = NF_BR_FORWARD;
	94	skb_forward_csum(skb);
	95	net = dev_net(indev);
	96	} else {
	97	if (unlikely(netpoll_tx_running(to->br->dev))) {
	98	if (!is_skb_forwardable(skb->dev, skb)) {
	99	kfree_skb(skb);
	100	} else {
	101	skb_push(skb, ETH_HLEN);
	102	br_netpoll_send_skb(to, skb);
	103	}
	104	return;
	105	}
	106	br_hook = NF_BR_LOCAL_OUT;
	107	net = dev_net(skb->dev);
	108	indev = NULL;
91d2c34a HX	109	}
91d2c34a HX	110
37b090e6 NA	111	NF_HOOK(NFPROTO_BRIDGE, br_hook,
37b090e6 NA	112	net, NULL, skb, indev, skb->dev,
713aefa3	113	br_forward_finish);
1da177e4 LT	114	}
1da177e4 LT	115
37b090e6 NA	116	static int deliver_clone(const struct net_bridge_port *prev,
37b090e6 NA	117	struct sk_buff *skb, bool local_orig)
1da177e4	118	{
37b090e6	119	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
1da177e4	120
37b090e6 NA	121	skb = skb_clone(skb, GFP_ATOMIC);
	122	if (!skb) {
	123	dev->stats.tx_dropped++;
	124	return -ENOMEM;
1da177e4 LT	125	}
1da177e4 LT	126
37b090e6 NA	127	__br_forward(prev, skb, local_orig);
37b090e6 NA	128	return 0;
1da177e4 LT	129	}
1da177e4 LT	130
37b090e6 NA	131	/**
	132	* br_forward - forward a packet to a specific port
	133	* @to: destination port
	134	* @skb: packet being forwarded
	135	* @local_rcv: packet will be received locally after forwarding
	136	* @local_orig: packet is locally originated
	137	*
	138	* Should be called with rcu_read_lock.
	139	*/
	140	void br_forward(const struct net_bridge_port *to,
	141	struct sk_buff *skb, bool local_rcv, bool local_orig)
1da177e4	142	{
b7af1472	143	if (to && should_deliver(to, skb)) {
b35c5f63	144	if (local_rcv)
37b090e6	145	deliver_clone(to, skb, local_orig);
7f7708f0	146	else
37b090e6	147	__br_forward(to, skb, local_orig);
1da177e4 LT	148	return;
	149	}
	150
b35c5f63	151	if (!local_rcv)
7f7708f0	152	kfree_skb(skb);
1da177e4	153	}
37b090e6	154	EXPORT_SYMBOL_GPL(br_forward);
025d89c2 HX	155
	156	static struct net_bridge_port *maybe_deliver(
	157	struct net_bridge_port prev, struct net_bridge_port p,
37b090e6	158	struct sk_buff *skb, bool local_orig)
025d89c2 HX	159	{
	160	int err;
	161
	162	if (!should_deliver(p, skb))
	163	return prev;
	164
	165	if (!prev)
	166	goto out;
	167
37b090e6	168	err = deliver_clone(prev, skb, local_orig);
025d89c2 HX	169	if (err)
	170	return ERR_PTR(err);
	171
	172	out:
	173	return p;
	174	}
	175
37b090e6 NA	176	/* called under rcu_read_lock */
	177	void br_flood(struct net_bridge br, struct sk_buff skb,
	178	bool unicast, bool local_rcv, bool local_orig)
1da177e4	179	{
1080ab95	180	u8 igmp_type = br_multicast_igmp_type(skb);
37b090e6	181	struct net_bridge_port *prev = NULL;
1080ab95	182	struct net_bridge_port *p;
1da177e4	183
1da177e4	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
37b090e6	196	prev = maybe_deliver(prev, p, skb, local_orig);
025d89c2 HX	197	if (IS_ERR(prev))
025d89c2 HX	198	goto out;
1080ab95	199	if (prev == p)
a65056ec	200	br_multicast_count(p->br, p, skb, igmp_type,
1080ab95	201	BR_MCAST_DIR_TX);
1da177e4 LT	202	}
1da177e4 LT	203
b33084be HX	204	if (!prev)
	205	goto out;
	206
b35c5f63	207	if (local_rcv)
37b090e6	208	deliver_clone(prev, skb, local_orig);
025d89c2	209	else
37b090e6	210	__br_forward(prev, skb, local_orig);
b33084be	211	return;
1da177e4	212
b33084be	213	out:
b35c5f63	214	if (!local_rcv)
b33084be	215	kfree_skb(skb);
1da177e4 LT	216	}
1da177e4 LT	217
5cb5e947 HX	218	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
5cb5e947 HX	219	/* called with rcu_read_lock */
37b090e6 NA	220	void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	221	struct sk_buff *skb,
	222	bool local_rcv, bool local_orig)
5cb5e947 HX	223	{
5cb5e947 HX	224	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
1080ab95	225	u8 igmp_type = br_multicast_igmp_type(skb);
5cb5e947	226	struct net_bridge *br = netdev_priv(dev);
afe0159d	227	struct net_bridge_port *prev = NULL;
5cb5e947 HX	228	struct net_bridge_port_group *p;
	229	struct hlist_node *rp;
	230
e8051688	231	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	232	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	233	while (p \|\| rp) {
afe0159d	234	struct net_bridge_port port, lport, *rport;
afe0159d	235
5cb5e947 HX	236	lport = p ? p->port : NULL;
	237	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	238	NULL;
	239
	240	port = (unsigned long)lport > (unsigned long)rport ?
	241	lport : rport;
	242
37b090e6	243	prev = maybe_deliver(prev, port, skb, local_orig);
5cb5e947 HX	244	if (IS_ERR(prev))
5cb5e947 HX	245	goto out;
1080ab95	246	if (prev == port)
a65056ec	247	br_multicast_count(port->br, port, skb, igmp_type,
1080ab95	248	BR_MCAST_DIR_TX);
5cb5e947 HX	249
5cb5e947 HX	250	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	251	p = rcu_dereference(p->next);
5cb5e947	252	if ((unsigned long)rport >= (unsigned long)port)
e8051688	253	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	254	}
	255
	256	if (!prev)
	257	goto out;
	258
b35c5f63	259	if (local_rcv)
37b090e6	260	deliver_clone(prev, skb, local_orig);
5cb5e947	261	else
37b090e6	262	__br_forward(prev, skb, local_orig);
5cb5e947 HX	263	return;
	264
	265	out:
b35c5f63	266	if (!local_rcv)
5cb5e947 HX	267	kfree_skb(skb);
5cb5e947 HX	268	}
5cb5e947	269	#endif