[linux-2.6-block.git] / net / bridge / br_forward.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	Forwarding decision
 *	Linux ethernet bridge
 *
 *	Authors:
 *	Lennert Buytenhek		<buytenh@gnu.org>
 */

#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) &&
		!br_skb_isolated(p, skb);
}

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

	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)
{
	skb->tstamp = 0;
	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, to, 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))) {
			skb_push(skb, ETH_HLEN);
			if (!is_skb_forwardable(skb->dev, skb))
				kfree_skb(skb);
			else
				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 (unlikely(!to))
		goto out;

	/* redirect to backup link if the destination port is down */
	if (rcu_access_pointer(to->backup_port) && !netif_carrier_ok(to->dev)) {
		struct net_bridge_port *backup_port;

		backup_port = rcu_dereference(to->backup_port);
		if (unlikely(!backup_port))
			goto out;
		to = backup_port;
	}

	if (should_deliver(to, skb)) {
		if (local_rcv)
			deliver_clone(to, skb, local_orig);
		else
			__br_forward(to, skb, local_orig);
		return;
	}

out:
	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)
{
	u8 igmp_type = br_multicast_igmp_type(skb);
	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:
	br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX);

	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)
{
	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, nor
		 * other traffic if flood off, except for traffic we originate
		 */
		switch (pkt_type) {
		case BR_PKT_UNICAST:
			if (!(p->flags & BR_FLOOD))
				continue;
			break;
		case BR_PKT_MULTICAST:
			if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
				continue;
			break;
		case BR_PKT_BROADCAST:
			if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
				continue;
			break;
		}

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

		prev = maybe_deliver(prev, p, skb, local_orig);
		if (IS_ERR(prev))
			goto out;
	}

	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
static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
			       const unsigned char *addr, bool local_orig)
{
	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	const unsigned char *src = eth_hdr(skb)->h_source;

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

	/* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
	if (skb->dev == p->dev && ether_addr_equal(src, addr))
		return;

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

	if (!is_broadcast_ether_addr(addr))
		memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);

	__br_forward(p, skb, local_orig);
}

/* 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;
	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 = hlist_entry_safe(rp, struct net_bridge_port, rlist);

		if ((unsigned long)lport > (unsigned long)rport) {
			port = lport;

			if (port->flags & BR_MULTICAST_TO_UNICAST) {
				maybe_deliver_addr(lport, skb, p->eth_addr,
						   local_orig);
				goto delivered;
			}
		} else {
			port = rport;
		}

		prev = maybe_deliver(prev, port, skb, local_orig);
		if (IS_ERR(prev))
			goto out;
delivered:
		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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* Forwarding decision
	4	* Linux ethernet bridge
	5	*
	6	* Authors:
	7	* Lennert Buytenhek <buytenh@gnu.org>
1da177e4 LT	8	*/
1da177e4 LT	9
025d89c2	10	#include <linux/err.h>
5a0e3ad6	11	#include <linux/slab.h>
1da177e4 LT	12	#include <linux/kernel.h>
1da177e4 LT	13	#include <linux/netdevice.h>
c06ee961	14	#include <linux/netpoll.h>
1da177e4	15	#include <linux/skbuff.h>
85ca719e	16	#include <linux/if_vlan.h>
1da177e4 LT	17	#include <linux/netfilter_bridge.h>
	18	#include "br_private.h"
	19
1a81a2e0	20	/* Don't forward packets to originating port or forwarding disabled */
9d6f229f	21	static inline int should_deliver(const struct net_bridge_port *p,
1da177e4 LT	22	const struct sk_buff *skb)
1da177e4 LT	23	{
2594e906 NA	24	struct net_bridge_vlan_group *vg;
2594e906 NA	25
907b1e6e	26	vg = nbp_vlan_group_rcu(p);
a97bfc1d	27	return ((p->flags & BR_HAIRPIN_MODE) \|\| skb->dev != p->dev) &&
6bc506b4	28	br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING &&
7d850abd NA	29	nbp_switchdev_allowed_egress(p, skb) &&
7d850abd NA	30	!br_skb_isolated(p, skb);
1da177e4 LT	31	}
1da177e4 LT	32
0c4b51f0	33	int br_dev_queue_push_xmit(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	34	{
28c1382f	35	skb_push(skb, ETH_HLEN);
df356d5e TM	36	if (!is_skb_forwardable(skb->dev, skb))
	37	goto drop;
	38
df356d5e	39	br_drop_fake_rtable(skb);
df356d5e TM	40
	41	if (skb->ip_summed == CHECKSUM_PARTIAL &&
	42	(skb->protocol == htons(ETH_P_8021Q) \|\|
	43	skb->protocol == htons(ETH_P_8021AD))) {
	44	int depth;
	45
	46	if (!__vlan_get_protocol(skb, skb->protocol, &depth))
	47	goto drop;
	48
	49	skb_set_network_header(skb, depth);
1da177e4 LT	50	}
1da177e4 LT	51
df356d5e TM	52	dev_queue_xmit(skb);
	53
	54	return 0;
	55
	56	drop:
	57	kfree_skb(skb);
1da177e4 LT	58	return 0;
1da177e4 LT	59	}
34666d46	60	EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
1da177e4	61
0c4b51f0	62	int br_forward_finish(struct net net, struct sock sk, struct sk_buff *skb)
1da177e4	63	{
41d1c883	64	skb->tstamp = 0;
29a26a56 EB	65	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
29a26a56 EB	66	net, sk, skb, NULL, skb->dev,
9ef513be	67	br_dev_queue_push_xmit);
1da177e4	68
1da177e4	69	}
34666d46	70	EXPORT_SYMBOL_GPL(br_forward_finish);
1da177e4	71
37b090e6 NA	72	static void __br_forward(const struct net_bridge_port *to,
37b090e6 NA	73	struct sk_buff *skb, bool local_orig)
1da177e4	74	{
2594e906	75	struct net_bridge_vlan_group *vg;
37b090e6 NA	76	struct net_device *indev;
	77	struct net *net;
	78	int br_hook;
2594e906	79
907b1e6e	80	vg = nbp_vlan_group_rcu(to);
11538d03	81	skb = br_handle_vlan(to->br, to, vg, skb);
78851988 VY	82	if (!skb)
	83	return;
	84
37b090e6	85	indev = skb->dev;
1da177e4	86	skb->dev = to->dev;
37b090e6 NA	87	if (!local_orig) {
37b090e6 NA	88	if (skb_warn_if_lro(skb)) {
91d2c34a	89	kfree_skb(skb);
37b090e6	90	return;
91d2c34a	91	}
37b090e6 NA	92	br_hook = NF_BR_FORWARD;
	93	skb_forward_csum(skb);
	94	net = dev_net(indev);
	95	} else {
	96	if (unlikely(netpoll_tx_running(to->br->dev))) {
28c1382f YW	97	skb_push(skb, ETH_HLEN);
28c1382f YW	98	if (!is_skb_forwardable(skb->dev, skb))
37b090e6	99	kfree_skb(skb);
28c1382f	100	else
37b090e6	101	br_netpoll_send_skb(to, skb);
37b090e6 NA	102	return;
	103	}
	104	br_hook = NF_BR_LOCAL_OUT;
	105	net = dev_net(skb->dev);
	106	indev = NULL;
91d2c34a HX	107	}
91d2c34a HX	108
37b090e6 NA	109	NF_HOOK(NFPROTO_BRIDGE, br_hook,
37b090e6 NA	110	net, NULL, skb, indev, skb->dev,
713aefa3	111	br_forward_finish);
1da177e4 LT	112	}
1da177e4 LT	113
37b090e6 NA	114	static int deliver_clone(const struct net_bridge_port *prev,
37b090e6 NA	115	struct sk_buff *skb, bool local_orig)
1da177e4	116	{
37b090e6	117	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
1da177e4	118
37b090e6 NA	119	skb = skb_clone(skb, GFP_ATOMIC);
	120	if (!skb) {
	121	dev->stats.tx_dropped++;
	122	return -ENOMEM;
1da177e4 LT	123	}
1da177e4 LT	124
37b090e6 NA	125	__br_forward(prev, skb, local_orig);
37b090e6 NA	126	return 0;
1da177e4 LT	127	}
1da177e4 LT	128
37b090e6 NA	129	/**
	130	* br_forward - forward a packet to a specific port
	131	* @to: destination port
	132	* @skb: packet being forwarded
	133	* @local_rcv: packet will be received locally after forwarding
	134	* @local_orig: packet is locally originated
	135	*
	136	* Should be called with rcu_read_lock.
	137	*/
	138	void br_forward(const struct net_bridge_port *to,
	139	struct sk_buff *skb, bool local_rcv, bool local_orig)
1da177e4	140	{
2756f68c NA	141	if (unlikely(!to))
	142	goto out;
	143
	144	/* redirect to backup link if the destination port is down */
	145	if (rcu_access_pointer(to->backup_port) && !netif_carrier_ok(to->dev)) {
	146	struct net_bridge_port *backup_port;
	147
	148	backup_port = rcu_dereference(to->backup_port);
	149	if (unlikely(!backup_port))
	150	goto out;
	151	to = backup_port;
	152	}
	153
	154	if (should_deliver(to, skb)) {
b35c5f63	155	if (local_rcv)
37b090e6	156	deliver_clone(to, skb, local_orig);
7f7708f0	157	else
37b090e6	158	__br_forward(to, skb, local_orig);
1da177e4 LT	159	return;
	160	}
	161
2756f68c	162	out:
b35c5f63	163	if (!local_rcv)
7f7708f0	164	kfree_skb(skb);
1da177e4	165	}
37b090e6	166	EXPORT_SYMBOL_GPL(br_forward);
025d89c2 HX	167
	168	static struct net_bridge_port *maybe_deliver(
	169	struct net_bridge_port prev, struct net_bridge_port p,
37b090e6	170	struct sk_buff *skb, bool local_orig)
025d89c2	171	{
847d44ef	172	u8 igmp_type = br_multicast_igmp_type(skb);
025d89c2 HX	173	int err;
	174
	175	if (!should_deliver(p, skb))
	176	return prev;
	177
	178	if (!prev)
	179	goto out;
	180
37b090e6	181	err = deliver_clone(prev, skb, local_orig);
025d89c2 HX	182	if (err)
025d89c2 HX	183	return ERR_PTR(err);
025d89c2	184	out:
847d44ef PNA	185	br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX);
847d44ef PNA	186
025d89c2 HX	187	return p;
	188	}
	189
37b090e6 NA	190	/* called under rcu_read_lock */
37b090e6 NA	191	void br_flood(struct net_bridge br, struct sk_buff skb,
8addd5e7	192	enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
1da177e4	193	{
37b090e6	194	struct net_bridge_port *prev = NULL;
1080ab95	195	struct net_bridge_port *p;
1da177e4	196
1da177e4	197	list_for_each_entry_rcu(p, &br->port_list, list) {
99f906e9 MM	198	/* Do not flood unicast traffic to ports that turn it off, nor
	199	* other traffic if flood off, except for traffic we originate
	200	*/
	201	switch (pkt_type) {
	202	case BR_PKT_UNICAST:
	203	if (!(p->flags & BR_FLOOD))
	204	continue;
	205	break;
	206	case BR_PKT_MULTICAST:
	207	if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
	208	continue;
	209	break;
	210	case BR_PKT_BROADCAST:
	211	if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
	212	continue;
	213	break;
	214	}
95850116 KP	215
	216	/* Do not flood to ports that enable proxy ARP */
	217	if (p->flags & BR_PROXYARP)
	218	continue;
821f1b21	219	if ((p->flags & (BR_PROXYARP_WIFI \| BR_NEIGH_SUPPRESS)) &&
842a9ae0 JM	220	BR_INPUT_SKB_CB(skb)->proxyarp_replied)
842a9ae0 JM	221	continue;
95850116	222
37b090e6	223	prev = maybe_deliver(prev, p, skb, local_orig);
025d89c2 HX	224	if (IS_ERR(prev))
025d89c2 HX	225	goto out;
1da177e4 LT	226	}
1da177e4 LT	227
b33084be HX	228	if (!prev)
	229	goto out;
	230
b35c5f63	231	if (local_rcv)
37b090e6	232	deliver_clone(prev, skb, local_orig);
025d89c2	233	else
37b090e6	234	__br_forward(prev, skb, local_orig);
b33084be	235	return;
1da177e4	236
b33084be	237	out:
b35c5f63	238	if (!local_rcv)
b33084be	239	kfree_skb(skb);
1da177e4 LT	240	}
1da177e4 LT	241
5cb5e947	242	#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
5b9d6b15 AB	243	static void maybe_deliver_addr(struct net_bridge_port p, struct sk_buff skb,
	244	const unsigned char *addr, bool local_orig)
	245	{
	246	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	247	const unsigned char *src = eth_hdr(skb)->h_source;
	248
	249	if (!should_deliver(p, skb))
	250	return;
	251
	252	/* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
	253	if (skb->dev == p->dev && ether_addr_equal(src, addr))
	254	return;
	255
	256	skb = skb_copy(skb, GFP_ATOMIC);
	257	if (!skb) {
	258	dev->stats.tx_dropped++;
	259	return;
	260	}
	261
	262	if (!is_broadcast_ether_addr(addr))
	263	memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
	264
	265	__br_forward(p, skb, local_orig);
	266	}
	267
5cb5e947	268	/* called with rcu_read_lock */
37b090e6 NA	269	void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
	270	struct sk_buff *skb,
	271	bool local_rcv, bool local_orig)
5cb5e947 HX	272	{
	273	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
	274	struct net_bridge *br = netdev_priv(dev);
afe0159d	275	struct net_bridge_port *prev = NULL;
5cb5e947 HX	276	struct net_bridge_port_group *p;
	277	struct hlist_node *rp;
	278
e8051688	279	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
83f6a740	280	p = mdst ? rcu_dereference(mdst->ports) : NULL;
5cb5e947	281	while (p \|\| rp) {
afe0159d	282	struct net_bridge_port port, lport, *rport;
afe0159d	283
5cb5e947	284	lport = p ? p->port : NULL;
d8fb1648	285	rport = hlist_entry_safe(rp, struct net_bridge_port, rlist);
5cb5e947	286
6db6f0ea FF	287	if ((unsigned long)lport > (unsigned long)rport) {
	288	port = lport;
	289
	290	if (port->flags & BR_MULTICAST_TO_UNICAST) {
	291	maybe_deliver_addr(lport, skb, p->eth_addr,
	292	local_orig);
	293	goto delivered;
	294	}
	295	} else {
	296	port = rport;
	297	}
5cb5e947	298
37b090e6	299	prev = maybe_deliver(prev, port, skb, local_orig);
5cb5e947 HX	300	if (IS_ERR(prev))
5cb5e947 HX	301	goto out;
847d44ef	302	delivered:
5cb5e947	303	if ((unsigned long)lport >= (unsigned long)port)
83f6a740	304	p = rcu_dereference(p->next);
5cb5e947	305	if ((unsigned long)rport >= (unsigned long)port)
e8051688	306	rp = rcu_dereference(hlist_next_rcu(rp));
5cb5e947 HX	307	}
	308
	309	if (!prev)
	310	goto out;
	311
b35c5f63	312	if (local_rcv)
37b090e6	313	deliver_clone(prev, skb, local_orig);
5cb5e947	314	else
37b090e6	315	__br_forward(prev, skb, local_orig);
5cb5e947 HX	316	return;
	317
	318	out:
b35c5f63	319	if (!local_rcv)
5cb5e947 HX	320	kfree_skb(skb);
5cb5e947 HX	321	}
5cb5e947	322	#endif