[net-next-2.6.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 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) &&
		p->state == BR_STATE_FORWARDING);
}

static inline unsigned 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)
{
	/* drop mtu oversized packets except gso */
	if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
		kfree_skb(skb);
	else {
		/* ip_fragment doesn't copy the MAC header */
		if (nf_bridge_maybe_copy_header(skb))
			kfree_skb(skb);
		else {
			skb_push(skb, ETH_HLEN);

#ifdef CONFIG_NET_POLL_CONTROLLER
			if (unlikely(skb->dev->priv_flags & IFF_IN_NETPOLL)) {
				netpoll_send_skb(skb->dev->npinfo->netpoll, skb);
				skb->dev->priv_flags &= ~IFF_IN_NETPOLL;
			} else
#endif
				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)
{
#ifdef CONFIG_NET_POLL_CONTROLLER
	struct net_bridge *br = to->br;
	if (unlikely(br->dev->priv_flags & IFF_IN_NETPOLL)) {
		struct netpoll *np;
		to->dev->npinfo = skb->dev->npinfo;
		np = skb->dev->npinfo->netpoll;
		np->real_dev = np->dev = to->dev;
		to->dev->priv_flags |= IFF_IN_NETPOLL;
	}
#endif
	skb->dev = to->dev;
	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
		br_forward_finish);
#ifdef CONFIG_NET_POLL_CONTROLLER
	if (skb->dev->npinfo)
		skb->dev->npinfo->netpoll->dev = br->dev;
#endif
}

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;
	}

	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 (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(br->router_list.first);
	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(rp->next);
	}

	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
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 FA	33	return (((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
3982d3d2 FA	34	p->state == BR_STATE_FORWARDING);
1da177e4 LT	35	}
1da177e4 LT	36
85ca719e SH	37	static inline unsigned packet_length(const struct sk_buff *skb)
	38	{
	39	return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
	40	}
	41
1da177e4 LT	42	int br_dev_queue_push_xmit(struct sk_buff *skb)
1da177e4 LT	43	{
7967168c	44	/* drop mtu oversized packets except gso */
89114afd	45	if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
1da177e4 LT	46	kfree_skb(skb);
1da177e4 LT	47	else {
e26c28e8	48	/* ip_fragment doesn't copy the MAC header */
3a13813e SH	49	if (nf_bridge_maybe_copy_header(skb))
3a13813e SH	50	kfree_skb(skb);
07317621	51	else {
3a13813e	52	skb_push(skb, ETH_HLEN);
1da177e4	53
c06ee961 WC	54	#ifdef CONFIG_NET_POLL_CONTROLLER
	55	if (unlikely(skb->dev->priv_flags & IFF_IN_NETPOLL)) {
	56	netpoll_send_skb(skb->dev->npinfo->netpoll, skb);
	57	skb->dev->priv_flags &= ~IFF_IN_NETPOLL;
	58	} else
	59	#endif
	60	dev_queue_xmit(skb);
3a13813e	61	}
1da177e4 LT	62	}
	63
	64	return 0;
	65	}
	66
	67	int br_forward_finish(struct sk_buff *skb)
	68	{
713aefa3	69	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
9ef513be	70	br_dev_queue_push_xmit);
1da177e4	71
1da177e4 LT	72	}
	73
	74	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	75	{
c06ee961 WC	76	#ifdef CONFIG_NET_POLL_CONTROLLER
	77	struct net_bridge *br = to->br;
	78	if (unlikely(br->dev->priv_flags & IFF_IN_NETPOLL)) {
	79	struct netpoll *np;
	80	to->dev->npinfo = skb->dev->npinfo;
	81	np = skb->dev->npinfo->netpoll;
	82	np->real_dev = np->dev = to->dev;
	83	to->dev->priv_flags \|= IFF_IN_NETPOLL;
	84	}
	85	#endif
1da177e4	86	skb->dev = to->dev;
713aefa3 JE	87	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
713aefa3 JE	88	br_forward_finish);
c06ee961 WC	89	#ifdef CONFIG_NET_POLL_CONTROLLER
	90	if (skb->dev->npinfo)
	91	skb->dev->npinfo->netpoll->dev = br->dev;
	92	#endif
1da177e4 LT	93	}
	94
	95	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	96	{
	97	struct net_device *indev;
	98
4906f998 HX	99	if (skb_warn_if_lro(skb)) {
	100	kfree_skb(skb);
	101	return;
	102	}
	103
1da177e4 LT	104	indev = skb->dev;
1da177e4 LT	105	skb->dev = to->dev;
35fc92a9	106	skb_forward_csum(skb);
1da177e4	107
713aefa3 JE	108	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
713aefa3 JE	109	br_forward_finish);
1da177e4 LT	110	}
	111
	112	/* called with rcu_read_lock */
	113	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	114	{
	115	if (should_deliver(to, skb)) {
	116	__br_deliver(to, skb);
	117	return;
	118	}
	119
	120	kfree_skb(skb);
	121	}
	122
	123	/* called with rcu_read_lock */
7f7708f0	124	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	125	{
4906f998	126	if (should_deliver(to, skb)) {
7f7708f0 MB	127	if (skb0)
	128	deliver_clone(to, skb, __br_forward);
	129	else
	130	__br_forward(to, skb);
1da177e4 LT	131	return;
	132	}
	133
7f7708f0 MB	134	if (!skb0)
7f7708f0 MB	135	kfree_skb(skb);
1da177e4 LT	136	}
1da177e4 LT	137
87faf3cc DM	138	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	139	struct sk_buff *skb,
025d89c2 HX	140	void (__packet_hook)(const struct net_bridge_port p,
	141	struct sk_buff *skb))
	142	{
fed396a5 HX	143	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
fed396a5 HX	144
025d89c2 HX	145	skb = skb_clone(skb, GFP_ATOMIC);
025d89c2 HX	146	if (!skb) {
025d89c2 HX	147	dev->stats.tx_dropped++;
	148	return -ENOMEM;
	149	}
	150
	151	__packet_hook(prev, skb);
	152	return 0;
	153	}
	154
	155	static struct net_bridge_port *maybe_deliver(
	156	struct net_bridge_port prev, struct net_bridge_port p,
	157	struct sk_buff *skb,
	158	void (__packet_hook)(const struct net_bridge_port p,
	159	struct sk_buff *skb))
	160	{
	161	int err;
	162
	163	if (!should_deliver(p, skb))
	164	return prev;
	165
	166	if (!prev)
	167	goto out;
	168
	169	err = deliver_clone(prev, skb, __packet_hook);
	170	if (err)
	171	return ERR_PTR(err);
	172
	173	out:
	174	return p;
	175	}
	176
1da177e4	177	/* called under bridge lock */
e081e1e3	178	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	179	struct sk_buff *skb0,
	180	void (__packet_hook)(const struct net_bridge_port p,
	181	struct sk_buff *skb))
1da177e4 LT	182	{
	183	struct net_bridge_port *p;
	184	struct net_bridge_port *prev;
	185
1da177e4 LT	186	prev = NULL;
	187
	188	list_for_each_entry_rcu(p, &br->port_list, list) {
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 */
e081e1e3	210	void br_flood_deliver(struct net_bridge br, struct sk_buff skb)
1da177e4	211	{
b33084be	212	br_flood(br, skb, NULL, __br_deliver);
1da177e4 LT	213	}
	214
	215	/* called under bridge lock */
b33084be HX	216	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
b33084be HX	217	struct sk_buff *skb2)
1da177e4	218	{
b33084be	219	br_flood(br, skb, skb2, __br_forward);
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
168d40ee	236	rp = rcu_dereference(br->router_list.first);
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)
168d40ee	255	rp = rcu_dereference(rp->next);
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