[GitHub/mt8127/android_kernel_alcatel_ttab.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/kernel.h>
#include <linux/netdevice.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_refrag calls ip_fragment, doesn't copy the MAC header. */
		if (nf_bridge_maybe_copy_header(skb))
			kfree_skb(skb);
		else {
			skb_push(skb, ETH_HLEN);

			dev_queue_xmit(skb);
		}
	}

	return 0;
}

int br_forward_finish(struct sk_buff *skb)
{
	return NF_HOOK(PF_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->dev = to->dev;
	NF_HOOK(PF_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;
	}

	indev = skb->dev;
	skb->dev = to->dev;
	skb_forward_csum(skb);

	NF_HOOK(PF_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))
{
	skb = skb_clone(skb, GFP_ATOMIC);
	if (!skb) {
		struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;

		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 *port;
	struct net_bridge_port *lport, *rport;
	struct net_bridge_port *prev;
	struct net_bridge_port_group *p;
	struct hlist_node *rp;

	prev = NULL;

	rp = br->router_list.first;
	p = mdst ? mdst->ports : NULL;
	while (p || rp) {
		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 = p->next;
		if ((unsigned long)rport >= (unsigned long)port)
			rp = 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>
1da177e4 LT	15	#include <linux/kernel.h>
	16	#include <linux/netdevice.h>
	17	#include <linux/skbuff.h>
85ca719e	18	#include <linux/if_vlan.h>
1da177e4 LT	19	#include <linux/netfilter_bridge.h>
	20	#include "br_private.h"
	21
87faf3cc DM	22	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	23	struct sk_buff *skb,
7f7708f0 MB	24	void (__packet_hook)(const struct net_bridge_port p,
	25	struct sk_buff *skb));
	26
9ef513be	27	/* Don't forward packets to originating port or forwarding diasabled */
9d6f229f	28	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	29	const struct sk_buff *skb)
1da177e4 LT	30	{
3982d3d2 FA	31	return (((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
3982d3d2 FA	32	p->state == BR_STATE_FORWARDING);
1da177e4 LT	33	}
1da177e4 LT	34
85ca719e SH	35	static inline unsigned packet_length(const struct sk_buff *skb)
	36	{
	37	return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
	38	}
	39
1da177e4 LT	40	int br_dev_queue_push_xmit(struct sk_buff *skb)
1da177e4 LT	41	{
7967168c	42	/* drop mtu oversized packets except gso */
89114afd	43	if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
1da177e4 LT	44	kfree_skb(skb);
1da177e4 LT	45	else {
1da177e4	46	/* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
3a13813e SH	47	if (nf_bridge_maybe_copy_header(skb))
3a13813e SH	48	kfree_skb(skb);
07317621	49	else {
3a13813e	50	skb_push(skb, ETH_HLEN);
1da177e4	51
3a13813e SH	52	dev_queue_xmit(skb);
3a13813e SH	53	}
1da177e4 LT	54	}
	55
	56	return 0;
	57	}
	58
	59	int br_forward_finish(struct sk_buff *skb)
	60	{
9ef513be SH	61	return NF_HOOK(PF_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
9ef513be SH	62	br_dev_queue_push_xmit);
1da177e4	63
1da177e4 LT	64	}
	65
	66	static void __br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	67	{
	68	skb->dev = to->dev;
1da177e4 LT	69	NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
	70	br_forward_finish);
	71	}
	72
	73	static void __br_forward(const struct net_bridge_port to, struct sk_buff skb)
	74	{
	75	struct net_device *indev;
	76
4906f998 HX	77	if (skb_warn_if_lro(skb)) {
	78	kfree_skb(skb);
	79	return;
	80	}
	81
1da177e4 LT	82	indev = skb->dev;
1da177e4 LT	83	skb->dev = to->dev;
35fc92a9	84	skb_forward_csum(skb);
1da177e4 LT	85
	86	NF_HOOK(PF_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
	87	br_forward_finish);
	88	}
	89
	90	/* called with rcu_read_lock */
	91	void br_deliver(const struct net_bridge_port to, struct sk_buff skb)
	92	{
	93	if (should_deliver(to, skb)) {
	94	__br_deliver(to, skb);
	95	return;
	96	}
	97
	98	kfree_skb(skb);
	99	}
	100
	101	/* called with rcu_read_lock */
7f7708f0	102	void br_forward(const struct net_bridge_port to, struct sk_buff skb, struct sk_buff *skb0)
1da177e4	103	{
4906f998	104	if (should_deliver(to, skb)) {
7f7708f0 MB	105	if (skb0)
	106	deliver_clone(to, skb, __br_forward);
	107	else
	108	__br_forward(to, skb);
1da177e4 LT	109	return;
	110	}
	111
7f7708f0 MB	112	if (!skb0)
7f7708f0 MB	113	kfree_skb(skb);
1da177e4 LT	114	}
1da177e4 LT	115
87faf3cc DM	116	static int deliver_clone(const struct net_bridge_port *prev,
87faf3cc DM	117	struct sk_buff *skb,
025d89c2 HX	118	void (__packet_hook)(const struct net_bridge_port p,
	119	struct sk_buff *skb))
	120	{
	121	skb = skb_clone(skb, GFP_ATOMIC);
	122	if (!skb) {
	123	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	124
	125	dev->stats.tx_dropped++;
	126	return -ENOMEM;
	127	}
	128
	129	__packet_hook(prev, skb);
	130	return 0;
	131	}
	132
	133	static struct net_bridge_port *maybe_deliver(
	134	struct net_bridge_port prev, struct net_bridge_port p,
	135	struct sk_buff *skb,
	136	void (__packet_hook)(const struct net_bridge_port p,
	137	struct sk_buff *skb))
	138	{
	139	int err;
	140
	141	if (!should_deliver(p, skb))
	142	return prev;
	143
	144	if (!prev)
	145	goto out;
	146
	147	err = deliver_clone(prev, skb, __packet_hook);
	148	if (err)
	149	return ERR_PTR(err);
	150
	151	out:
	152	return p;
	153	}
	154
1da177e4	155	/* called under bridge lock */
e081e1e3	156	static void br_flood(struct net_bridge br, struct sk_buff skb,
b33084be HX	157	struct sk_buff *skb0,
	158	void (__packet_hook)(const struct net_bridge_port p,
	159	struct sk_buff *skb))
1da177e4 LT	160	{
	161	struct net_bridge_port *p;
	162	struct net_bridge_port *prev;
	163
1da177e4 LT	164	prev = NULL;
	165
	166	list_for_each_entry_rcu(p, &br->port_list, list) {
025d89c2 HX	167	prev = maybe_deliver(prev, p, skb, __packet_hook);
	168	if (IS_ERR(prev))
	169	goto out;
1da177e4 LT	170	}
1da177e4 LT	171
b33084be HX	172	if (!prev)
	173	goto out;
	174
025d89c2 HX	175	if (skb0)
	176	deliver_clone(prev, skb, __packet_hook);
	177	else
	178	__packet_hook(prev, skb);
b33084be	179	return;
1da177e4	180
b33084be HX	181	out:
	182	if (!skb0)
	183	kfree_skb(skb);
1da177e4 LT	184	}
	185
	186
	187	/* called with rcu_read_lock */
e081e1e3	188	void br_flood_deliver(struct net_bridge br, struct sk_buff skb)
1da177e4	189	{
b33084be	190	br_flood(br, skb, NULL, __br_deliver);
1da177e4 LT	191	}
	192
	193	/* called under bridge lock */
b33084be HX	194	void br_flood_forward(struct net_bridge br, struct sk_buff skb,
b33084be HX	195	struct sk_buff *skb2)
1da177e4	196	{
b33084be	197	br_flood(br, skb, skb2, __br_forward);
1da177e4	198	}
5cb5e947 HX	199
	200	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
	201	/* called with rcu_read_lock */
	202	static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	203	struct sk_buff skb, struct sk_buff skb0,
	204	void (*__packet_hook)(
	205	const struct net_bridge_port *p,
	206	struct sk_buff *skb))
	207	{
	208	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	209	struct net_bridge *br = netdev_priv(dev);
	210	struct net_bridge_port *port;
	211	struct net_bridge_port lport, rport;
	212	struct net_bridge_port *prev;
	213	struct net_bridge_port_group *p;
	214	struct hlist_node *rp;
	215
	216	prev = NULL;
	217
	218	rp = br->router_list.first;
	219	p = mdst ? mdst->ports : NULL;
	220	while (p \|\| rp) {
	221	lport = p ? p->port : NULL;
	222	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	223	NULL;
	224
	225	port = (unsigned long)lport > (unsigned long)rport ?
	226	lport : rport;
	227
	228	prev = maybe_deliver(prev, port, skb, __packet_hook);
	229	if (IS_ERR(prev))
	230	goto out;
	231
	232	if ((unsigned long)lport >= (unsigned long)port)
	233	p = p->next;
	234	if ((unsigned long)rport >= (unsigned long)port)
	235	rp = rp->next;
	236	}
	237
	238	if (!prev)
	239	goto out;
	240
	241	if (skb0)
	242	deliver_clone(prev, skb, __packet_hook);
	243	else
	244	__packet_hook(prev, skb);
	245	return;
	246
	247	out:
	248	if (!skb0)
	249	kfree_skb(skb);
	250	}
	251
	252	/* called with rcu_read_lock */
	253	void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
	254	struct sk_buff *skb)
	255	{
	256	br_multicast_flood(mdst, skb, NULL, __br_deliver);
	257	}
	258
	259	/* called with rcu_read_lock */
	260	void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
	261	struct sk_buff skb, struct sk_buff skb2)
	262	{
263	br_multicast_flood(mdst, skb, skb2, __br_forward);
264	}
265	#endif