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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Forwarding decision
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 * 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
Herbert Xu025d89c2010-02-27 19:41:43 +000014#include <linux/err.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090015#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/kernel.h>
17#include <linux/netdevice.h>
WANG Congc06ee962010-05-06 00:48:24 -070018#include <linux/netpoll.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/skbuff.h>
Stephen Hemminger85ca7192006-04-26 02:39:19 -070020#include <linux/if_vlan.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/netfilter_bridge.h>
22#include "br_private.h"
23
David S. Miller87faf3c2010-03-16 14:37:47 -070024static int deliver_clone(const struct net_bridge_port *prev,
25 struct sk_buff *skb,
Michael Braun7f7708f2010-03-16 00:26:22 -070026 void (*__packet_hook)(const struct net_bridge_port *p,
27 struct sk_buff *skb));
28
Stephen Hemminger9ef513b2006-05-25 15:58:54 -070029/* Don't forward packets to originating port or forwarding diasabled */
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +090030static inline int should_deliver(const struct net_bridge_port *p,
Linus Torvalds1da177e2005-04-16 15:20:36 -070031 const struct sk_buff *skb)
32{
Fischer, Anna3982d3d2009-08-13 06:55:16 +000033 return (((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
34 p->state == BR_STATE_FORWARDING);
Linus Torvalds1da177e2005-04-16 15:20:36 -070035}
36
Stephen Hemminger85ca7192006-04-26 02:39:19 -070037static 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070042int br_dev_queue_push_xmit(struct sk_buff *skb)
43{
Herbert Xu79671682006-06-22 02:40:14 -070044 /* drop mtu oversized packets except gso */
Herbert Xu89114af2006-07-08 13:34:32 -070045 if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 kfree_skb(skb);
47 else {
Bart De Schuymere26c28e2010-04-13 11:41:39 +020048 /* ip_fragment doesn't copy the MAC header */
Stephen Hemminger3a138132006-08-26 20:28:30 -070049 if (nf_bridge_maybe_copy_header(skb))
50 kfree_skb(skb);
Stephen Hemminger07317622006-08-29 17:48:17 -070051 else {
Stephen Hemminger3a138132006-08-26 20:28:30 -070052 skb_push(skb, ETH_HLEN);
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
WANG Congc06ee962010-05-06 00:48:24 -070054#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);
Stephen Hemminger3a138132006-08-26 20:28:30 -070061 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 }
63
64 return 0;
65}
66
67int br_forward_finish(struct sk_buff *skb)
68{
Jan Engelhardt713aefa2010-03-23 04:07:21 +010069 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
Stephen Hemminger9ef513b2006-05-25 15:58:54 -070070 br_dev_queue_push_xmit);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Linus Torvalds1da177e2005-04-16 15:20:36 -070072}
73
74static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
75{
WANG Congc06ee962010-05-06 00:48:24 -070076#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
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 skb->dev = to->dev;
Jan Engelhardt713aefa2010-03-23 04:07:21 +010087 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
88 br_forward_finish);
WANG Congc06ee962010-05-06 00:48:24 -070089#ifdef CONFIG_NET_POLL_CONTROLLER
90 if (skb->dev->npinfo)
91 skb->dev->npinfo->netpoll->dev = br->dev;
92#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070093}
94
95static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
96{
97 struct net_device *indev;
98
Herbert Xu4906f992009-02-09 15:07:18 -080099 if (skb_warn_if_lro(skb)) {
100 kfree_skb(skb);
101 return;
102 }
103
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 indev = skb->dev;
105 skb->dev = to->dev;
Herbert Xu35fc92a2007-03-26 23:22:20 -0700106 skb_forward_csum(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
Jan Engelhardt713aefa2010-03-23 04:07:21 +0100108 NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
109 br_forward_finish);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110}
111
112/* called with rcu_read_lock */
113void 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 */
Michael Braun7f7708f2010-03-16 00:26:22 -0700124void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
Herbert Xu4906f992009-02-09 15:07:18 -0800126 if (should_deliver(to, skb)) {
Michael Braun7f7708f2010-03-16 00:26:22 -0700127 if (skb0)
128 deliver_clone(to, skb, __br_forward);
129 else
130 __br_forward(to, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 return;
132 }
133
Michael Braun7f7708f2010-03-16 00:26:22 -0700134 if (!skb0)
135 kfree_skb(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136}
137
David S. Miller87faf3c2010-03-16 14:37:47 -0700138static int deliver_clone(const struct net_bridge_port *prev,
139 struct sk_buff *skb,
Herbert Xu025d89c2010-02-27 19:41:43 +0000140 void (*__packet_hook)(const struct net_bridge_port *p,
141 struct sk_buff *skb))
142{
143 skb = skb_clone(skb, GFP_ATOMIC);
144 if (!skb) {
145 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
146
147 dev->stats.tx_dropped++;
148 return -ENOMEM;
149 }
150
151 __packet_hook(prev, skb);
152 return 0;
153}
154
155static 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
173out:
174 return p;
175}
176
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177/* called under bridge lock */
Herbert Xue081e1e2007-09-16 16:20:48 -0700178static void br_flood(struct net_bridge *br, struct sk_buff *skb,
Herbert Xub33084b2010-02-27 19:41:41 +0000179 struct sk_buff *skb0,
180 void (*__packet_hook)(const struct net_bridge_port *p,
181 struct sk_buff *skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
183 struct net_bridge_port *p;
184 struct net_bridge_port *prev;
185
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 prev = NULL;
187
188 list_for_each_entry_rcu(p, &br->port_list, list) {
Herbert Xu025d89c2010-02-27 19:41:43 +0000189 prev = maybe_deliver(prev, p, skb, __packet_hook);
190 if (IS_ERR(prev))
191 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 }
193
Herbert Xub33084b2010-02-27 19:41:41 +0000194 if (!prev)
195 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
Herbert Xu025d89c2010-02-27 19:41:43 +0000197 if (skb0)
198 deliver_clone(prev, skb, __packet_hook);
199 else
200 __packet_hook(prev, skb);
Herbert Xub33084b2010-02-27 19:41:41 +0000201 return;
202
203out:
204 if (!skb0)
205 kfree_skb(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206}
207
208
209/* called with rcu_read_lock */
Herbert Xue081e1e2007-09-16 16:20:48 -0700210void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211{
Herbert Xub33084b2010-02-27 19:41:41 +0000212 br_flood(br, skb, NULL, __br_deliver);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213}
214
215/* called under bridge lock */
Herbert Xub33084b2010-02-27 19:41:41 +0000216void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
217 struct sk_buff *skb2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
Herbert Xub33084b2010-02-27 19:41:41 +0000219 br_flood(br, skb, skb2, __br_forward);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220}
Herbert Xu5cb5e942010-02-27 19:41:46 +0000221
222#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
223/* called with rcu_read_lock */
224static 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);
stephen hemmingerafe01592010-04-27 15:01:07 +0000232 struct net_bridge_port *prev = NULL;
Herbert Xu5cb5e942010-02-27 19:41:46 +0000233 struct net_bridge_port_group *p;
234 struct hlist_node *rp;
235
stephen hemminger168d40e2010-04-27 15:01:05 +0000236 rp = rcu_dereference(br->router_list.first);
stephen hemminger83f6a742010-04-27 15:01:06 +0000237 p = mdst ? rcu_dereference(mdst->ports) : NULL;
Herbert Xu5cb5e942010-02-27 19:41:46 +0000238 while (p || rp) {
stephen hemmingerafe01592010-04-27 15:01:07 +0000239 struct net_bridge_port *port, *lport, *rport;
240
Herbert Xu5cb5e942010-02-27 19:41:46 +0000241 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)
stephen hemminger83f6a742010-04-27 15:01:06 +0000253 p = rcu_dereference(p->next);
Herbert Xu5cb5e942010-02-27 19:41:46 +0000254 if ((unsigned long)rport >= (unsigned long)port)
stephen hemminger168d40e2010-04-27 15:01:05 +0000255 rp = rcu_dereference(rp->next);
Herbert Xu5cb5e942010-02-27 19:41:46 +0000256 }
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
267out:
268 if (!skb0)
269 kfree_skb(skb);
270}
271
272/* called with rcu_read_lock */
273void 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 */
280void 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