[mirror_ubuntu-zesty-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"

/* 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)
{
	struct net_bridge_vlan_group *vg;

	vg = nbp_vlan_group_rcu(p);
	return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
		br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING &&
		nbp_switchdev_allowed_egress(p, skb);
}

int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	if (!is_skb_forwardable(skb->dev, skb))
		goto drop;

	skb_push(skb, ETH_HLEN);
	br_drop_fake_rtable(skb);

	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	    (skb->protocol == htons(ETH_P_8021Q) ||
	     skb->protocol == htons(ETH_P_8021AD))) {
		int depth;

		if (!__vlan_get_protocol(skb, skb->protocol, &depth))
			goto drop;

		skb_set_network_header(skb, depth);
	}

	dev_queue_xmit(skb);

	return 0;

drop:
	kfree_skb(skb);
	return 0;
}
EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);

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

}
EXPORT_SYMBOL_GPL(br_forward_finish);

static void __br_forward(const struct net_bridge_port *to,
			 struct sk_buff *skb, bool local_orig)
{
	struct net_bridge_vlan_group *vg;
	struct net_device *indev;
	struct net *net;
	int br_hook;

	vg = nbp_vlan_group_rcu(to);
	skb = br_handle_vlan(to->br, vg, skb);
	if (!skb)
		return;

	indev = skb->dev;
	skb->dev = to->dev;
	if (!local_orig) {
		if (skb_warn_if_lro(skb)) {
			kfree_skb(skb);
			return;
		}
		br_hook = NF_BR_FORWARD;
		skb_forward_csum(skb);
		net = dev_net(indev);
	} else {
		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;
		}
		br_hook = NF_BR_LOCAL_OUT;
		net = dev_net(skb->dev);
		indev = NULL;
	}

	NF_HOOK(NFPROTO_BRIDGE, br_hook,
		net, NULL, skb, indev, skb->dev,
		br_forward_finish);
}

static int deliver_clone(const struct net_bridge_port *prev,
			 struct sk_buff *skb, bool local_orig)
{
	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;

	skb = skb_clone(skb, GFP_ATOMIC);
	if (!skb) {
		dev->stats.tx_dropped++;
		return -ENOMEM;
	}

	__br_forward(prev, skb, local_orig);
	return 0;
}

/**
 * br_forward - forward a packet to a specific port
 * @to: destination port
 * @skb: packet being forwarded
 * @local_rcv: packet will be received locally after forwarding
 * @local_orig: packet is locally originated
 *
 * Should be called with rcu_read_lock.
 */
void br_forward(const struct net_bridge_port *to,
		struct sk_buff *skb, bool local_rcv, bool local_orig)
{
	if (to && should_deliver(to, skb)) {
		if (local_rcv)
			deliver_clone(to, skb, local_orig);
		else
			__br_forward(to, skb, local_orig);
		return;
	}

	if (!local_rcv)
		kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(br_forward);

static struct net_bridge_port *maybe_deliver(
	struct net_bridge_port *prev, struct net_bridge_port *p,
	struct sk_buff *skb, bool local_orig)
{
	int err;

	if (!should_deliver(p, skb))
		return prev;

	if (!prev)
		goto out;

	err = deliver_clone(prev, skb, local_orig);
	if (err)
		return ERR_PTR(err);

out:
	return p;
}

/* called under rcu_read_lock */
void br_flood(struct net_bridge *br, struct sk_buff *skb,
	      enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
{
	u8 igmp_type = br_multicast_igmp_type(skb);
	struct net_bridge_port *prev = NULL;
	struct net_bridge_port *p;

	list_for_each_entry_rcu(p, &br->port_list, list) {
		/* Do not flood unicast traffic to ports that turn it off */
		if (pkt_type == BR_PKT_UNICAST && !(p->flags & BR_FLOOD))
			continue;
		if (pkt_type == BR_PKT_MULTICAST &&
		    !(p->flags & BR_MCAST_FLOOD))
			continue;

		/* Do not flood to ports that enable proxy ARP */
		if (p->flags & BR_PROXYARP)
			continue;
		if ((p->flags & BR_PROXYARP_WIFI) &&
		    BR_INPUT_SKB_CB(skb)->proxyarp_replied)
			continue;

		prev = maybe_deliver(prev, p, skb, local_orig);
		if (IS_ERR(prev))
			goto out;
		if (prev == p)
			br_multicast_count(p->br, p, skb, igmp_type,
					   BR_MCAST_DIR_TX);
	}

	if (!prev)
		goto out;

	if (local_rcv)
		deliver_clone(prev, skb, local_orig);
	else
		__br_forward(prev, skb, local_orig);
	return;

out:
	if (!local_rcv)
		kfree_skb(skb);
}

#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
/* called with rcu_read_lock */
void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
			struct sk_buff *skb,
			bool local_rcv, bool local_orig)
{
	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	u8 igmp_type = br_multicast_igmp_type(skb);
	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, local_orig);
		if (IS_ERR(prev))
			goto out;
		if (prev == port)
			br_multicast_count(port->br, port, skb, igmp_type,
					   BR_MCAST_DIR_TX);

		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 (local_rcv)
		deliver_clone(prev, skb, local_orig);
	else
		__br_forward(prev, skb, local_orig);
	return;

out:
	if (!local_rcv)
		kfree_skb(skb);
}
#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
1a81a2e0	24	/* Don't forward packets to originating port or forwarding disabled */
9d6f229f	25	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	26	const struct sk_buff *skb)
1da177e4 LT	27	{
2594e906 NA	28	struct net_bridge_vlan_group *vg;
2594e906 NA	29
907b1e6e	30	vg = nbp_vlan_group_rcu(p);
a97bfc1d	31	return ((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
6bc506b4 IS	32	br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING &&
6bc506b4 IS	33	nbp_switchdev_allowed_egress(p, skb);
1da177e4 LT	34	}
1da177e4 LT	35
0c4b51f0	36	int br_dev_queue_push_xmit(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	37	{
df356d5e TM	38	if (!is_skb_forwardable(skb->dev, skb))
	39	goto drop;
	40
	41	skb_push(skb, ETH_HLEN);
	42	br_drop_fake_rtable(skb);
df356d5e TM	43
	44	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	45	(skb->protocol == htons(ETH_P_8021Q) \|\|
	46	skb->protocol == htons(ETH_P_8021AD))) {
	47	int depth;
	48
	49	if (!__vlan_get_protocol(skb, skb->protocol, &depth))
	50	goto drop;
	51
	52	skb_set_network_header(skb, depth);
1da177e4 LT	53	}
1da177e4 LT	54
df356d5e TM	55	dev_queue_xmit(skb);
	56
	57	return 0;
	58
	59	drop:
	60	kfree_skb(skb);
1da177e4 LT	61	return 0;
1da177e4 LT	62	}
34666d46	63	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4	64
0c4b51f0	65	int br_forward_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	66	{
29a26a56 EB	67	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
29a26a56 EB	68	net, sk, skb, NULL, skb->dev,
9ef513be	69	br_dev_queue_push_xmit);
1da177e4	70
1da177e4	71	}
34666d46	72	EXPORT_SYMBOL_GPL(br_forward_finish);
1da177e4	73
37b090e6 NA	74	static void __br_forward(const struct net_bridge_port *to,
37b090e6 NA	75	struct sk_buff *skb, bool local_orig)
1da177e4	76	{
2594e906	77	struct net_bridge_vlan_group *vg;
37b090e6 NA	78	struct net_device *indev;
	79	struct net *net;
	80	int br_hook;
2594e906	81
907b1e6e	82	vg = nbp_vlan_group_rcu(to);
2594e906	83	skb = br_handle_vlan(to->br, vg, skb);
78851988 VY	84	if (!skb)
	85	return;
	86
37b090e6	87	indev = skb->dev;
1da177e4	88	skb->dev = to->dev;
37b090e6 NA	89	if (!local_orig) {
37b090e6 NA	90	if (skb_warn_if_lro(skb)) {
91d2c34a	91	kfree_skb(skb);
37b090e6	92	return;
91d2c34a	93	}
37b090e6 NA	94	br_hook = NF_BR_FORWARD;
	95	skb_forward_csum(skb);
	96	net = dev_net(indev);
	97	} else {
	98	if (unlikely(netpoll_tx_running(to->br->dev))) {
	99	if (!is_skb_forwardable(skb->dev, skb)) {
	100	kfree_skb(skb);
	101	} else {
	102	skb_push(skb, ETH_HLEN);
	103	br_netpoll_send_skb(to, skb);
	104	}
	105	return;
	106	}
	107	br_hook = NF_BR_LOCAL_OUT;
	108	net = dev_net(skb->dev);
	109	indev = NULL;
91d2c34a HX	110	}
91d2c34a HX	111
37b090e6 NA	112	NF_HOOK(NFPROTO_BRIDGE, br_hook,
37b090e6 NA	113	net, NULL, skb, indev, skb->dev,
713aefa3	114	br_forward_finish);
1da177e4 LT	115	}
1da177e4 LT	116
37b090e6 NA	117	static int deliver_clone(const struct net_bridge_port *prev,
37b090e6 NA	118	struct sk_buff *skb, bool local_orig)
1da177e4	119	{
37b090e6	120	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
1da177e4	121
37b090e6 NA	122	skb = skb_clone(skb, GFP_ATOMIC);
	123	if (!skb) {
	124	dev->stats.tx_dropped++;
	125	return -ENOMEM;
1da177e4 LT	126	}
1da177e4 LT	127
37b090e6 NA	128	__br_forward(prev, skb, local_orig);
37b090e6 NA	129	return 0;
1da177e4 LT	130	}
1da177e4 LT	131
37b090e6 NA	132	/**
	133	* br_forward - forward a packet to a specific port
	134	* @to: destination port
	135	* @skb: packet being forwarded
	136	* @local_rcv: packet will be received locally after forwarding
	137	* @local_orig: packet is locally originated
	138	*
	139	* Should be called with rcu_read_lock.
	140	*/
	141	void br_forward(const struct net_bridge_port *to,
	142	struct sk_buff *skb, bool local_rcv, bool local_orig)
1da177e4	143	{
b7af1472	144	if (to && should_deliver(to, skb)) {
b35c5f63	145	if (local_rcv)
37b090e6	146	deliver_clone(to, skb, local_orig);
7f7708f0	147	else
37b090e6	148	__br_forward(to, skb, local_orig);
1da177e4 LT	149	return;
	150	}
	151
b35c5f63	152	if (!local_rcv)
7f7708f0	153	kfree_skb(skb);
1da177e4	154	}
37b090e6	155	EXPORT_SYMBOL_GPL(br_forward);
025d89c2 HX	156
	157	static struct net_bridge_port *maybe_deliver(
	158	struct net_bridge_port prev, struct net_bridge_port p,
37b090e6	159	struct sk_buff *skb, bool local_orig)
025d89c2 HX	160	{
	161	int err;
	162
	163	if (!should_deliver(p, skb))
	164	return prev;
	165
	166	if (!prev)
	167	goto out;
	168
37b090e6	169	err = deliver_clone(prev, skb, local_orig);
025d89c2 HX	170	if (err)
	171	return ERR_PTR(err);
	172
	173	out:
	174	return p;
	175	}
	176
37b090e6 NA	177	/* called under rcu_read_lock */
37b090e6 NA	178	void br_flood(struct net_bridge br, struct sk_buff skb,
8addd5e7	179	enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
1da177e4	180	{
1080ab95	181	u8 igmp_type = br_multicast_igmp_type(skb);
37b090e6	182	struct net_bridge_port *prev = NULL;
1080ab95	183	struct net_bridge_port *p;
1da177e4	184
1da177e4	185	list_for_each_entry_rcu(p, &br->port_list, list) {
867a5943	186	/* Do not flood unicast traffic to ports that turn it off */
8addd5e7	187	if (pkt_type == BR_PKT_UNICAST && !(p->flags & BR_FLOOD))
867a5943	188	continue;
b6cb5ac8 NA	189	if (pkt_type == BR_PKT_MULTICAST &&
	190	!(p->flags & BR_MCAST_FLOOD))
	191	continue;
95850116 KP	192
	193	/* Do not flood to ports that enable proxy ARP */
	194	if (p->flags & BR_PROXYARP)
	195	continue;
842a9ae0 JM	196	if ((p->flags & BR_PROXYARP_WIFI) &&
	197	BR_INPUT_SKB_CB(skb)->proxyarp_replied)
	198	continue;
95850116	199
37b090e6	200	prev = maybe_deliver(prev, p, skb, local_orig);
025d89c2 HX	201	if (IS_ERR(prev))
025d89c2 HX	202	goto out;
1080ab95	203	if (prev == p)
a65056ec	204	br_multicast_count(p->br, p, skb, igmp_type,
1080ab95	205	BR_MCAST_DIR_TX);
1da177e4 LT	206	}
1da177e4 LT	207
b33084be HX	208	if (!prev)
	209	goto out;
	210
b35c5f63	211	if (local_rcv)
37b090e6	212	deliver_clone(prev, skb, local_orig);
025d89c2	213	else
37b090e6	214	__br_forward(prev, skb, local_orig);
b33084be	215	return;
1da177e4	216
b33084be	217	out:
b35c5f63	218	if (!local_rcv)
b33084be	219	kfree_skb(skb);
1da177e4 LT	220	}
1da177e4 LT	221
5cb5e947 HX	222	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
5cb5e947 HX	223	/* called with rcu_read_lock */
37b090e6 NA	224	void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	225	struct sk_buff *skb,
	226	bool local_rcv, bool local_orig)
5cb5e947 HX	227	{
5cb5e947 HX	228	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
1080ab95	229	u8 igmp_type = br_multicast_igmp_type(skb);
5cb5e947	230	struct net_bridge *br = netdev_priv(dev);
afe0159d	231	struct net_bridge_port *prev = NULL;
5cb5e947 HX	232	struct net_bridge_port_group *p;
	233	struct hlist_node *rp;
	234
e8051688	235	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	236	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	237	while (p \|\| rp) {
afe0159d	238	struct net_bridge_port port, lport, *rport;
afe0159d	239
5cb5e947 HX	240	lport = p ? p->port : NULL;
	241	rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
	242	NULL;
	243
	244	port = (unsigned long)lport > (unsigned long)rport ?
	245	lport : rport;
	246
37b090e6	247	prev = maybe_deliver(prev, port, skb, local_orig);
5cb5e947 HX	248	if (IS_ERR(prev))
5cb5e947 HX	249	goto out;
1080ab95	250	if (prev == port)
a65056ec	251	br_multicast_count(port->br, port, skb, igmp_type,
1080ab95	252	BR_MCAST_DIR_TX);
5cb5e947 HX	253
5cb5e947 HX	254	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	255	p = rcu_dereference(p->next);
5cb5e947	256	if ((unsigned long)rport >= (unsigned long)port)
e8051688	257	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	258	}
	259
	260	if (!prev)
	261	goto out;
	262
b35c5f63	263	if (local_rcv)
37b090e6	264	deliver_clone(prev, skb, local_orig);
5cb5e947	265	else
37b090e6	266	__br_forward(prev, skb, local_orig);
5cb5e947 HX	267	return;
	268
	269	out:
b35c5f63	270	if (!local_rcv)
5cb5e947 HX	271	kfree_skb(skb);
5cb5e947 HX	272	}
5cb5e947	273	#endif