br_forward.c 7.37 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
11
12
13
/*
 *	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.
 */

14
#include <linux/err.h>
15
#include <linux/slab.h>
Linus Torvalds's avatar
Linus Torvalds committed
16
17
#include <linux/kernel.h>
#include <linux/netdevice.h>
18
#include <linux/netpoll.h>
Linus Torvalds's avatar
Linus Torvalds committed
19
#include <linux/skbuff.h>
20
#include <linux/if_vlan.h>
Linus Torvalds's avatar
Linus Torvalds committed
21
22
23
#include <linux/netfilter_bridge.h>
#include "br_private.h"

24
25
static int deliver_clone(const struct net_bridge_port *prev,
			 struct sk_buff *skb,
26
27
28
			 void (*__packet_hook)(const struct net_bridge_port *p,
					       struct sk_buff *skb));

tanxiaojun's avatar
tanxiaojun committed
29
/* Don't forward packets to originating port or forwarding disabled */
30
static inline int should_deliver(const struct net_bridge_port *p,
Linus Torvalds's avatar
Linus Torvalds committed
31
32
				 const struct sk_buff *skb)
{
33
34
	struct net_bridge_vlan_group *vg;

35
	vg = nbp_vlan_group_rcu(p);
36
	return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
37
		br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING;
Linus Torvalds's avatar
Linus Torvalds committed
38
39
}

40
int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
Linus Torvalds's avatar
Linus Torvalds committed
41
{
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
	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);
Linus Torvalds's avatar
Linus Torvalds committed
57
58
	}

59
60
61
62
63
64
	dev_queue_xmit(skb);

	return 0;

drop:
	kfree_skb(skb);
Linus Torvalds's avatar
Linus Torvalds committed
65
66
	return 0;
}
67
EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
Linus Torvalds's avatar
Linus Torvalds committed
68

69
int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
Linus Torvalds's avatar
Linus Torvalds committed
70
{
71
72
	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
		       net, sk, skb, NULL, skb->dev,
73
		       br_dev_queue_push_xmit);
Linus Torvalds's avatar
Linus Torvalds committed
74
75

}
76
EXPORT_SYMBOL_GPL(br_forward_finish);
Linus Torvalds's avatar
Linus Torvalds committed
77
78
79

static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
{
80
81
	struct net_bridge_vlan_group *vg;

82
	vg = nbp_vlan_group_rcu(to);
83
	skb = br_handle_vlan(to->br, vg, skb);
84
85
86
	if (!skb)
		return;

Linus Torvalds's avatar
Linus Torvalds committed
87
	skb->dev = to->dev;
Herbert Xu's avatar
Herbert Xu committed
88

89
	if (unlikely(netpoll_tx_running(to->br->dev))) {
90
		if (!is_skb_forwardable(skb->dev, skb))
Herbert Xu's avatar
Herbert Xu committed
91
92
93
94
95
96
97
98
			kfree_skb(skb);
		else {
			skb_push(skb, ETH_HLEN);
			br_netpoll_send_skb(to, skb);
		}
		return;
	}

99
100
	NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
		dev_net(skb->dev), NULL, skb,NULL, skb->dev,
101
		br_forward_finish);
Linus Torvalds's avatar
Linus Torvalds committed
102
103
104
105
}

static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
{
106
	struct net_bridge_vlan_group *vg;
Linus Torvalds's avatar
Linus Torvalds committed
107
108
	struct net_device *indev;

Herbert Xu's avatar
Herbert Xu committed
109
110
111
112
113
	if (skb_warn_if_lro(skb)) {
		kfree_skb(skb);
		return;
	}

114
	vg = nbp_vlan_group_rcu(to);
115
	skb = br_handle_vlan(to->br, vg, skb);
116
117
118
	if (!skb)
		return;

Linus Torvalds's avatar
Linus Torvalds committed
119
120
	indev = skb->dev;
	skb->dev = to->dev;
121
	skb_forward_csum(skb);
Linus Torvalds's avatar
Linus Torvalds committed
122

123
124
	NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD,
		dev_net(indev), NULL, skb, indev, skb->dev,
125
		br_forward_finish);
Linus Torvalds's avatar
Linus Torvalds committed
126
127
128
129
130
}

/* called with rcu_read_lock */
void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
{
131
	if (to && should_deliver(to, skb)) {
Linus Torvalds's avatar
Linus Torvalds committed
132
133
134
135
136
137
		__br_deliver(to, skb);
		return;
	}

	kfree_skb(skb);
}
138
EXPORT_SYMBOL_GPL(br_deliver);
Linus Torvalds's avatar
Linus Torvalds committed
139
140

/* called with rcu_read_lock */
141
142
void br_forward(const struct net_bridge_port *to, struct sk_buff *skb,
		bool local_rcv)
Linus Torvalds's avatar
Linus Torvalds committed
143
{
144
	if (to && should_deliver(to, skb)) {
145
		if (local_rcv)
146
147
148
			deliver_clone(to, skb, __br_forward);
		else
			__br_forward(to, skb);
Linus Torvalds's avatar
Linus Torvalds committed
149
150
151
		return;
	}

152
	if (!local_rcv)
153
		kfree_skb(skb);
Linus Torvalds's avatar
Linus Torvalds committed
154
155
}

156
157
static int deliver_clone(const struct net_bridge_port *prev,
			 struct sk_buff *skb,
158
159
160
			 void (*__packet_hook)(const struct net_bridge_port *p,
					       struct sk_buff *skb))
{
161
162
	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;

163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
	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;
}

Linus Torvalds's avatar
Linus Torvalds committed
195
/* called under bridge lock */
196
static void br_flood(struct net_bridge *br, struct sk_buff *skb,
197
		     void (*__packet_hook)(const struct net_bridge_port *p,
198
					   struct sk_buff *skb),
199
		     bool local_rcv, bool unicast)
Linus Torvalds's avatar
Linus Torvalds committed
200
{
201
	u8 igmp_type = br_multicast_igmp_type(skb);
Linus Torvalds's avatar
Linus Torvalds committed
202
	struct net_bridge_port *prev;
203
	struct net_bridge_port *p;
Linus Torvalds's avatar
Linus Torvalds committed
204
205
206
207

	prev = NULL;

	list_for_each_entry_rcu(p, &br->port_list, list) {
208
209
210
		/* Do not flood unicast traffic to ports that turn it off */
		if (unicast && !(p->flags & BR_FLOOD))
			continue;
211
212
213
214

		/* Do not flood to ports that enable proxy ARP */
		if (p->flags & BR_PROXYARP)
			continue;
215
216
217
		if ((p->flags & BR_PROXYARP_WIFI) &&
		    BR_INPUT_SKB_CB(skb)->proxyarp_replied)
			continue;
218

219
220
221
		prev = maybe_deliver(prev, p, skb, __packet_hook);
		if (IS_ERR(prev))
			goto out;
222
		if (prev == p)
223
			br_multicast_count(p->br, p, skb, igmp_type,
224
					   BR_MCAST_DIR_TX);
Linus Torvalds's avatar
Linus Torvalds committed
225
226
	}

227
228
229
	if (!prev)
		goto out;

230
	if (local_rcv)
231
232
233
		deliver_clone(prev, skb, __packet_hook);
	else
		__packet_hook(prev, skb);
234
	return;
Linus Torvalds's avatar
Linus Torvalds committed
235

236
out:
237
	if (!local_rcv)
238
		kfree_skb(skb);
Linus Torvalds's avatar
Linus Torvalds committed
239
240
241
242
}


/* called with rcu_read_lock */
243
void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, bool unicast)
Linus Torvalds's avatar
Linus Torvalds committed
244
{
245
	br_flood(br, skb, __br_deliver, false, unicast);
Linus Torvalds's avatar
Linus Torvalds committed
246
247
248
}

/* called under bridge lock */
249
void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
250
		      bool local_rcv, bool unicast)
Linus Torvalds's avatar
Linus Torvalds committed
251
{
252
	br_flood(br, skb, __br_forward, local_rcv, unicast);
Linus Torvalds's avatar
Linus Torvalds committed
253
}
254
255
256
257

#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
/* called with rcu_read_lock */
static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
258
			       struct sk_buff *skb,
259
260
			       void (*__packet_hook)(
					const struct net_bridge_port *p,
261
262
					struct sk_buff *skb),
			       bool local_rcv)
263
264
{
	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
265
	u8 igmp_type = br_multicast_igmp_type(skb);
266
	struct net_bridge *br = netdev_priv(dev);
267
	struct net_bridge_port *prev = NULL;
268
269
270
	struct net_bridge_port_group *p;
	struct hlist_node *rp;

271
	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
272
	p = mdst ? rcu_dereference(mdst->ports) : NULL;
273
	while (p || rp) {
274
275
		struct net_bridge_port *port, *lport, *rport;

276
277
278
279
280
281
282
283
284
285
		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;
286
		if (prev == port)
287
			br_multicast_count(port->br, port, skb, igmp_type,
288
					   BR_MCAST_DIR_TX);
289
290

		if ((unsigned long)lport >= (unsigned long)port)
291
			p = rcu_dereference(p->next);
292
		if ((unsigned long)rport >= (unsigned long)port)
293
			rp = rcu_dereference(hlist_next_rcu(rp));
294
295
296
297
298
	}

	if (!prev)
		goto out;

299
	if (local_rcv)
300
301
302
303
304
305
		deliver_clone(prev, skb, __packet_hook);
	else
		__packet_hook(prev, skb);
	return;

out:
306
	if (!local_rcv)
307
308
309
310
311
312
313
		kfree_skb(skb);
}

/* called with rcu_read_lock */
void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
			  struct sk_buff *skb)
{
314
	br_multicast_flood(mdst, skb, __br_deliver, false);
315
316
317
318
}

/* called with rcu_read_lock */
void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
319
			  struct sk_buff *skb, bool local_rcv)
320
{
321
	br_multicast_flood(mdst, skb, __br_forward, local_rcv);
322
323
}
#endif