[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;
}

static inline unsigned int packet_length(const struct sk_buff *skb)
{
	return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
}

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) ||
	    (packet_length(skb) > skb->dev->mtu && !skb_is_gso(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 (packet_length(skb) > skb->dev->mtu && !skb_is_gso(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	}
1da177e4 LT	37
95c96174	38	static inline unsigned int packet_length(const struct sk_buff *skb)
85ca719e SH	39	{
	40	return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
	41	}
	42
1da177e4 LT	43	int br_dev_queue_push_xmit(struct sk_buff *skb)
1da177e4 LT	44	{
f88de8de CG	45	/* ip_fragment doesn't copy the MAC header */
	46	if (nf_bridge_maybe_copy_header(skb) \|\|
	47	(packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))) {
1da177e4	48	kfree_skb(skb);
f88de8de CG	49	} else {
f88de8de CG	50	skb_push(skb, ETH_HLEN);
a881e963	51	br_drop_fake_rtable(skb);
f88de8de	52	dev_queue_xmit(skb);
1da177e4 LT	53	}
	54
	55	return 0;
	56	}
	57
	58	int br_forward_finish(struct sk_buff *skb)
	59	{
713aefa3	60	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
9ef513be	61	br_dev_queue_push_xmit);
1da177e4	62
1da177e4 LT	63	}
	64
	65	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	66	{
78851988 VY	67	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	68	if (!skb)
	69	return;
	70
1da177e4	71	skb->dev = to->dev;
91d2c34a	72
e15c3c22	73	if (unlikely(netpoll_tx_running(to->br->dev))) {
91d2c34a HX	74	if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
	75	kfree_skb(skb);
	76	else {
	77	skb_push(skb, ETH_HLEN);
	78	br_netpoll_send_skb(to, skb);
	79	}
	80	return;
	81	}
	82
713aefa3 JE	83	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
713aefa3 JE	84	br_forward_finish);
1da177e4 LT	85	}
	86
	87	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	88	{
	89	struct net_device *indev;
	90
4906f998 HX	91	if (skb_warn_if_lro(skb)) {
	92	kfree_skb(skb);
	93	return;
	94	}
	95
78851988 VY	96	skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
	97	if (!skb)
	98	return;
	99
1da177e4 LT	100	indev = skb->dev;
1da177e4 LT	101	skb->dev = to->dev;
35fc92a9	102	skb_forward_csum(skb);
1da177e4	103
713aefa3 JE	104	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
713aefa3 JE	105	br_forward_finish);
1da177e4 LT	106	}
	107
	108	/* called with rcu_read_lock */
	109	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	110	{
43598813	111	if (to && should_deliver(to, skb)) {
1da177e4 LT	112	__br_deliver(to, skb);
	113	return;
	114	}
	115
	116	kfree_skb(skb);
	117	}
	118
	119	/* called with rcu_read_lock */
7f7708f0	120	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	121	{
4906f998	122	if (should_deliver(to, skb)) {
7f7708f0 MB	123	if (skb0)
	124	deliver_clone(to, skb, __br_forward);
	125	else
	126	__br_forward(to, skb);
1da177e4 LT	127	return;
	128	}
	129
7f7708f0 MB	130	if (!skb0)
7f7708f0 MB	131	kfree_skb(skb);
1da177e4 LT	132	}
1da177e4 LT	133
87faf3cc DM	134	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	135	struct sk_buff *skb,
025d89c2 HX	136	void (__packet_hook)(const struct net_bridge_port p,
	137	struct sk_buff *skb))
	138	{
fed396a5 HX	139	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
fed396a5 HX	140
025d89c2 HX	141	skb = skb_clone(skb, GFP_ATOMIC);
025d89c2 HX	142	if (!skb) {
025d89c2 HX	143	dev->stats.tx_dropped++;
	144	return -ENOMEM;
	145	}
	146
	147	__packet_hook(prev, skb);
	148	return 0;
	149	}
	150
	151	static struct net_bridge_port *maybe_deliver(
	152	struct net_bridge_port prev, struct net_bridge_port p,
	153	struct sk_buff *skb,
	154	void (__packet_hook)(const struct net_bridge_port p,
	155	struct sk_buff *skb))
	156	{
	157	int err;
	158
	159	if (!should_deliver(p, skb))
	160	return prev;
	161
	162	if (!prev)
	163	goto out;
	164
	165	err = deliver_clone(prev, skb, __packet_hook);
	166	if (err)
	167	return ERR_PTR(err);
	168
	169	out:
	170	return p;
	171	}
	172
1da177e4	173	/* called under bridge lock */
e081e1e3	174	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	175	struct sk_buff *skb0,
b33084be HX	176	void (__packet_hook)(const struct net_bridge_port p,
867a5943 VY	177	struct sk_buff *skb),
867a5943 VY	178	bool unicast)
1da177e4 LT	179	{
	180	struct net_bridge_port *p;
	181	struct net_bridge_port *prev;
	182
1da177e4 LT	183	prev = NULL;
	184
	185	list_for_each_entry_rcu(p, &br->port_list, list) {
867a5943 VY	186	/* Do not flood unicast traffic to ports that turn it off */
	187	if (unicast && !(p->flags & BR_FLOOD))
	188	continue;
025d89c2 HX	189	prev = maybe_deliver(prev, p, skb, __packet_hook);
	190	if (IS_ERR(prev))
	191	goto out;
1da177e4 LT	192	}
1da177e4 LT	193
b33084be HX	194	if (!prev)
	195	goto out;
	196
025d89c2 HX	197	if (skb0)
	198	deliver_clone(prev, skb, __packet_hook);
	199	else
	200	__packet_hook(prev, skb);
b33084be	201	return;
1da177e4	202
b33084be HX	203	out:
	204	if (!skb0)
	205	kfree_skb(skb);
1da177e4 LT	206	}
	207
	208
	209	/* called with rcu_read_lock */
867a5943	210	void br_flood_deliver(struct net_bridge br, struct sk_buff skb, bool unicast)
1da177e4	211	{
867a5943	212	br_flood(br, skb, NULL, __br_deliver, unicast);
1da177e4 LT	213	}
	214
	215	/* called under bridge lock */
b33084be	216	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
867a5943	217	struct sk_buff *skb2, bool unicast)
1da177e4	218	{
867a5943	219	br_flood(br, skb, skb2, __br_forward, unicast);
1da177e4	220	}
5cb5e947 HX	221
	222	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	223	/* called with rcu_read_lock */
	224	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	225	struct sk_buff skb, struct sk_buff skb0,
	226	void (*__packet_hook)(
	227	const struct net_bridge_port *p,
	228	struct sk_buff *skb))
	229	{
	230	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	231	struct net_bridge *br = netdev_priv(dev);
afe0159d	232	struct net_bridge_port *prev = NULL;
5cb5e947 HX	233	struct net_bridge_port_group *p;
	234	struct hlist_node *rp;
	235
e8051688	236	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	237	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	238	while (p \|\| rp) {
afe0159d	239	struct net_bridge_port port, lport, *rport;
afe0159d	240
5cb5e947 HX	241	lport = p ? p->port : NULL;
	242	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	243	NULL;
	244
	245	port = (unsigned long)lport > (unsigned long)rport ?
	246	lport : rport;
	247
	248	prev = maybe_deliver(prev, port, skb, __packet_hook);
	249	if (IS_ERR(prev))
	250	goto out;
	251
	252	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	253	p = rcu_dereference(p->next);
5cb5e947	254	if ((unsigned long)rport >= (unsigned long)port)
e8051688	255	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	256	}
	257
	258	if (!prev)
	259	goto out;
	260
	261	if (skb0)
	262	deliver_clone(prev, skb, __packet_hook);
	263	else
	264	__packet_hook(prev, skb);
	265	return;
	266
	267	out:
	268	if (!skb0)
	269	kfree_skb(skb);
	270	}
	271
	272	/* called with rcu_read_lock */
	273	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	274	struct sk_buff *skb)
	275	{
	276	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	277	}
	278
	279	/* called with rcu_read_lock */
	280	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	281	struct sk_buff skb, struct sk_buff skb2)
	282	{
	283	br_multicast_flood(mdst, skb, skb2, __br_forward);
	284	}
	285	#endif