[linux.git] / net / bridge / br_forward.c

/*
 *	Forwarding decision
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<[email protected]>
 *
 *	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 diasabled */
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))
{
	struct net_bridge_port *p;
	struct net_bridge_port *prev;

	prev = NULL;

	list_for_each_entry_rcu(p, &br->port_list, list) {
		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)
{
	br_flood(br, skb, NULL, __br_deliver);
}

/* called under bridge lock */
void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
		      struct sk_buff *skb2)
{
	br_flood(br, skb, skb2, __br_forward);
}

#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 <[email protected]>
	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
9ef513be	29	/* Don't forward packets to originating port or forwarding diasabled */
9d6f229f	30	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	31	const struct sk_buff *skb)
1da177e4 LT	32	{
3982d3d2	33	return (((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
85f46c6b	34	br_allowed_egress(p->br, nbp_get_vlan_info(p), skb) &&
3982d3d2	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,
	176	void (__packet_hook)(const struct net_bridge_port p,
	177	struct sk_buff *skb))
1da177e4 LT	178	{
	179	struct net_bridge_port *p;
	180	struct net_bridge_port *prev;
	181
1da177e4 LT	182	prev = NULL;
	183
	184	list_for_each_entry_rcu(p, &br->port_list, list) {
025d89c2 HX	185	prev = maybe_deliver(prev, p, skb, __packet_hook);
	186	if (IS_ERR(prev))
	187	goto out;
1da177e4 LT	188	}
1da177e4 LT	189
b33084be HX	190	if (!prev)
	191	goto out;
	192
025d89c2 HX	193	if (skb0)
	194	deliver_clone(prev, skb, __packet_hook);
	195	else
	196	__packet_hook(prev, skb);
b33084be	197	return;
1da177e4	198
b33084be HX	199	out:
	200	if (!skb0)
	201	kfree_skb(skb);
1da177e4 LT	202	}
	203
	204
	205	/* called with rcu_read_lock */
e081e1e3	206	void br_flood_deliver(struct net_bridge br, struct sk_buff skb)
1da177e4	207	{
b33084be	208	br_flood(br, skb, NULL, __br_deliver);
1da177e4 LT	209	}
	210
	211	/* called under bridge lock */
b33084be HX	212	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
b33084be HX	213	struct sk_buff *skb2)
1da177e4	214	{
b33084be	215	br_flood(br, skb, skb2, __br_forward);
1da177e4	216	}
5cb5e947 HX	217
	218	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	219	/* called with rcu_read_lock */
	220	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	221	struct sk_buff skb, struct sk_buff skb0,
	222	void (*__packet_hook)(
	223	const struct net_bridge_port *p,
	224	struct sk_buff *skb))
	225	{
	226	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	227	struct net_bridge *br = netdev_priv(dev);
afe0159d	228	struct net_bridge_port *prev = NULL;
5cb5e947 HX	229	struct net_bridge_port_group *p;
	230	struct hlist_node *rp;
	231
e8051688	232	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	233	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	234	while (p \|\| rp) {
afe0159d	235	struct net_bridge_port port, lport, *rport;
afe0159d	236
5cb5e947 HX	237	lport = p ? p->port : NULL;
	238	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	239	NULL;
	240
	241	port = (unsigned long)lport > (unsigned long)rport ?
	242	lport : rport;
	243
	244	prev = maybe_deliver(prev, port, skb, __packet_hook);
	245	if (IS_ERR(prev))
	246	goto out;
	247
	248	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	249	p = rcu_dereference(p->next);
5cb5e947	250	if ((unsigned long)rport >= (unsigned long)port)
e8051688	251	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	252	}
	253
	254	if (!prev)
	255	goto out;
	256
	257	if (skb0)
	258	deliver_clone(prev, skb, __packet_hook);
	259	else
	260	__packet_hook(prev, skb);
	261	return;
	262
	263	out:
	264	if (!skb0)
	265	kfree_skb(skb);
	266	}
	267
	268	/* called with rcu_read_lock */
	269	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	270	struct sk_buff *skb)
	271	{
	272	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	273	}
	274
	275	/* called with rcu_read_lock */
	276	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	277	struct sk_buff skb, struct sk_buff skb2)
	278	{
	279	br_multicast_flood(mdst, skb, skb2, __br_forward);
	280	}
	281	#endif