[linux-block.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 sk_buff *skb)
{
	/* ip_fragment doesn't copy the MAC header */
	if (nf_bridge_maybe_copy_header(skb) ||
	    !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;
}

int br_forward_finish(struct sk_buff *skb)
{
	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
		       br_dev_queue_push_xmit);

}

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, 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, 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);
}

/* 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;
		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	}
	37
	38	int br_dev_queue_push_xmit(struct sk_buff *skb)
	39	{
f88de8de CG	40	/* ip_fragment doesn't copy the MAC header */
f88de8de CG	41	if (nf_bridge_maybe_copy_header(skb) \|\|
f6367b46	42	!is_skb_forwardable(skb->dev, skb)) {
1da177e4	43	kfree_skb(skb);
f88de8de CG	44	} else {
f88de8de CG	45	skb_push(skb, ETH_HLEN);
a881e963	46	br_drop_fake_rtable(skb);
f88de8de	47	dev_queue_xmit(skb);
1da177e4 LT	48	}
	49
	50	return 0;
	51	}
	52
	53	int br_forward_finish(struct sk_buff *skb)
	54	{
713aefa3	55	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
9ef513be	56	br_dev_queue_push_xmit);
1da177e4	57
1da177e4 LT	58	}
	59
	60	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	61	{
78851988 VY	62	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	63	if (!skb)
	64	return;
	65
1da177e4	66	skb->dev = to->dev;
91d2c34a	67
e15c3c22	68	if (unlikely(netpoll_tx_running(to->br->dev))) {
f6367b46	69	if (!is_skb_forwardable(skb->dev, skb))
91d2c34a HX	70	kfree_skb(skb);
	71	else {
	72	skb_push(skb, ETH_HLEN);
	73	br_netpoll_send_skb(to, skb);
	74	}
	75	return;
	76	}
	77
713aefa3 JE	78	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
713aefa3 JE	79	br_forward_finish);
1da177e4 LT	80	}
	81
	82	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	83	{
	84	struct net_device *indev;
	85
4906f998 HX	86	if (skb_warn_if_lro(skb)) {
	87	kfree_skb(skb);
	88	return;
	89	}
	90
78851988 VY	91	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	92	if (!skb)
	93	return;
	94
1da177e4 LT	95	indev = skb->dev;
1da177e4 LT	96	skb->dev = to->dev;
35fc92a9	97	skb_forward_csum(skb);
1da177e4	98
713aefa3 JE	99	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
713aefa3 JE	100	br_forward_finish);
1da177e4 LT	101	}
	102
	103	/* called with rcu_read_lock */
	104	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	105	{
43598813	106	if (to && should_deliver(to, skb)) {
1da177e4 LT	107	__br_deliver(to, skb);
	108	return;
	109	}
	110
	111	kfree_skb(skb);
	112	}
	113
	114	/* called with rcu_read_lock */
7f7708f0	115	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	116	{
4906f998	117	if (should_deliver(to, skb)) {
7f7708f0 MB	118	if (skb0)
	119	deliver_clone(to, skb, __br_forward);
	120	else
	121	__br_forward(to, skb);
1da177e4 LT	122	return;
	123	}
	124
7f7708f0 MB	125	if (!skb0)
7f7708f0 MB	126	kfree_skb(skb);
1da177e4 LT	127	}
1da177e4 LT	128
87faf3cc DM	129	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	130	struct sk_buff *skb,
025d89c2 HX	131	void (__packet_hook)(const struct net_bridge_port p,
	132	struct sk_buff *skb))
	133	{
fed396a5 HX	134	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
fed396a5 HX	135
025d89c2 HX	136	skb = skb_clone(skb, GFP_ATOMIC);
025d89c2 HX	137	if (!skb) {
025d89c2 HX	138	dev->stats.tx_dropped++;
	139	return -ENOMEM;
	140	}
	141
	142	__packet_hook(prev, skb);
	143	return 0;
	144	}
	145
	146	static struct net_bridge_port *maybe_deliver(
	147	struct net_bridge_port prev, struct net_bridge_port p,
	148	struct sk_buff *skb,
	149	void (__packet_hook)(const struct net_bridge_port p,
	150	struct sk_buff *skb))
	151	{
	152	int err;
	153
	154	if (!should_deliver(p, skb))
	155	return prev;
	156
	157	if (!prev)
	158	goto out;
	159
	160	err = deliver_clone(prev, skb, __packet_hook);
	161	if (err)
	162	return ERR_PTR(err);
	163
	164	out:
	165	return p;
	166	}
	167
1da177e4	168	/* called under bridge lock */
e081e1e3	169	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	170	struct sk_buff *skb0,
b33084be HX	171	void (__packet_hook)(const struct net_bridge_port p,
867a5943 VY	172	struct sk_buff *skb),
867a5943 VY	173	bool unicast)
1da177e4 LT	174	{
	175	struct net_bridge_port *p;
	176	struct net_bridge_port *prev;
	177
1da177e4 LT	178	prev = NULL;
	179
	180	list_for_each_entry_rcu(p, &br->port_list, list) {
867a5943 VY	181	/* Do not flood unicast traffic to ports that turn it off */
	182	if (unicast && !(p->flags & BR_FLOOD))
	183	continue;
025d89c2 HX	184	prev = maybe_deliver(prev, p, skb, __packet_hook);
	185	if (IS_ERR(prev))
	186	goto out;
1da177e4 LT	187	}
1da177e4 LT	188
b33084be HX	189	if (!prev)
	190	goto out;
	191
025d89c2 HX	192	if (skb0)
	193	deliver_clone(prev, skb, __packet_hook);
	194	else
	195	__packet_hook(prev, skb);
b33084be	196	return;
1da177e4	197
b33084be HX	198	out:
	199	if (!skb0)
	200	kfree_skb(skb);
1da177e4 LT	201	}
	202
	203
	204	/* called with rcu_read_lock */
867a5943	205	void br_flood_deliver(struct net_bridge br, struct sk_buff skb, bool unicast)
1da177e4	206	{
867a5943	207	br_flood(br, skb, NULL, __br_deliver, unicast);
1da177e4 LT	208	}
	209
	210	/* called under bridge lock */
b33084be	211	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
867a5943	212	struct sk_buff *skb2, bool unicast)
1da177e4	213	{
867a5943	214	br_flood(br, skb, skb2, __br_forward, unicast);
1da177e4	215	}
5cb5e947 HX	216
	217	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	218	/* called with rcu_read_lock */
	219	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	220	struct sk_buff skb, struct sk_buff skb0,
	221	void (*__packet_hook)(
	222	const struct net_bridge_port *p,
	223	struct sk_buff *skb))
	224	{
	225	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	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
	243	prev = maybe_deliver(prev, port, skb, __packet_hook);
	244	if (IS_ERR(prev))
	245	goto out;
	246
	247	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	248	p = rcu_dereference(p->next);
5cb5e947	249	if ((unsigned long)rport >= (unsigned long)port)
e8051688	250	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	251	}
	252
	253	if (!prev)
	254	goto out;
	255
	256	if (skb0)
	257	deliver_clone(prev, skb, __packet_hook);
	258	else
	259	__packet_hook(prev, skb);
	260	return;
	261
	262	out:
	263	if (!skb0)
	264	kfree_skb(skb);
	265	}
	266
	267	/* called with rcu_read_lock */
	268	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	269	struct sk_buff *skb)
	270	{
	271	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	272	}
	273
	274	/* called with rcu_read_lock */
	275	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	276	struct sk_buff skb, struct sk_buff skb2)
	277	{
	278	br_multicast_flood(mdst, skb, skb2, __br_forward);
	279	}
	280	#endif