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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) &&
Vlad Yasevich85f46c62013-02-13 12:00:11 +000034 br_allowed_egress(p->br, nbp_get_vlan_info(p), skb) &&
Fischer, Anna3982d3d2009-08-13 06:55:16 +000035 p->state == BR_STATE_FORWARDING);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036}
37
Eric Dumazet95c96172012-04-15 05:58:06 +000038static inline unsigned int packet_length(const struct sk_buff *skb)
Stephen Hemminger85ca7192006-04-26 02:39:19 -070039{
40 return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
41}
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043int br_dev_queue_push_xmit(struct sk_buff *skb)
44{
Changli Gaof88de8d2010-12-25 03:41:30 +000045 /* ip_fragment doesn't copy the MAC header */
46 if (nf_bridge_maybe_copy_header(skb) ||
47 (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 kfree_skb(skb);
Changli Gaof88de8d2010-12-25 03:41:30 +000049 } else {
50 skb_push(skb, ETH_HLEN);
Peter Huang (Peng)a881e962012-04-19 20:12:51 +000051 br_drop_fake_rtable(skb);
Changli Gaof88de8d2010-12-25 03:41:30 +000052 dev_queue_xmit(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 }
54
55 return 0;
56}
57
58int br_forward_finish(struct sk_buff *skb)
59{
Jan Engelhardt713aefa2010-03-23 04:07:21 +010060 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
Stephen Hemminger9ef513b2006-05-25 15:58:54 -070061 br_dev_queue_push_xmit);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063}
64
65static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
66{
Vlad Yasevich78851982013-02-13 12:00:14 +000067 skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
68 if (!skb)
69 return;
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 skb->dev = to->dev;
Herbert Xu91d2c342010-06-10 16:12:50 +000072
Amerigo Wange15c3c222012-08-10 01:24:45 +000073 if (unlikely(netpoll_tx_running(to->br->dev))) {
Herbert Xu91d2c342010-06-10 16:12:50 +000074 if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
75 kfree_skb(skb);
76 else {
77 skb_push(skb, ETH_HLEN);
78 br_netpoll_send_skb(to, skb);
79 }
80 return;
81 }
82
Jan Engelhardt713aefa2010-03-23 04:07:21 +010083 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
84 br_forward_finish);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085}
86
87static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
88{
89 struct net_device *indev;
90
Herbert Xu4906f992009-02-09 15:07:18 -080091 if (skb_warn_if_lro(skb)) {
92 kfree_skb(skb);
93 return;
94 }
95
Vlad Yasevich78851982013-02-13 12:00:14 +000096 skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
97 if (!skb)
98 return;
99
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 indev = skb->dev;
101 skb->dev = to->dev;
Herbert Xu35fc92a2007-03-26 23:22:20 -0700102 skb_forward_csum(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103
Jan Engelhardt713aefa2010-03-23 04:07:21 +0100104 NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
105 br_forward_finish);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106}
107
108/* called with rcu_read_lock */
109void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
110{
stephen hemminger43598812011-12-08 07:17:49 +0000111 if (to && should_deliver(to, skb)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 __br_deliver(to, skb);
113 return;
114 }
115
116 kfree_skb(skb);
117}
118
119/* called with rcu_read_lock */
Michael Braun7f7708f2010-03-16 00:26:22 -0700120void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121{
Herbert Xu4906f992009-02-09 15:07:18 -0800122 if (should_deliver(to, skb)) {
Michael Braun7f7708f2010-03-16 00:26:22 -0700123 if (skb0)
124 deliver_clone(to, skb, __br_forward);
125 else
126 __br_forward(to, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 return;
128 }
129
Michael Braun7f7708f2010-03-16 00:26:22 -0700130 if (!skb0)
131 kfree_skb(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132}
133
David S. Miller87faf3c2010-03-16 14:37:47 -0700134static int deliver_clone(const struct net_bridge_port *prev,
135 struct sk_buff *skb,
Herbert Xu025d89c2010-02-27 19:41:43 +0000136 void (*__packet_hook)(const struct net_bridge_port *p,
137 struct sk_buff *skb))
138{
Herbert Xufed396a2010-06-15 21:43:07 -0700139 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
140
Herbert Xu025d89c2010-02-27 19:41:43 +0000141 skb = skb_clone(skb, GFP_ATOMIC);
142 if (!skb) {
Herbert Xu025d89c2010-02-27 19:41:43 +0000143 dev->stats.tx_dropped++;
144 return -ENOMEM;
145 }
146
147 __packet_hook(prev, skb);
148 return 0;
149}
150
151static struct net_bridge_port *maybe_deliver(
152 struct net_bridge_port *prev, struct net_bridge_port *p,
153 struct sk_buff *skb,
154 void (*__packet_hook)(const struct net_bridge_port *p,
155 struct sk_buff *skb))
156{
157 int err;
158
159 if (!should_deliver(p, skb))
160 return prev;
161
162 if (!prev)
163 goto out;
164
165 err = deliver_clone(prev, skb, __packet_hook);
166 if (err)
167 return ERR_PTR(err);
168
169out:
170 return p;
171}
172
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173/* called under bridge lock */
Herbert Xue081e1e2007-09-16 16:20:48 -0700174static void br_flood(struct net_bridge *br, struct sk_buff *skb,
Herbert Xub33084b2010-02-27 19:41:41 +0000175 struct sk_buff *skb0,
176 void (*__packet_hook)(const struct net_bridge_port *p,
Vlad Yasevich867a5942013-06-05 10:08:01 -0400177 struct sk_buff *skb),
178 bool unicast)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179{
180 struct net_bridge_port *p;
181 struct net_bridge_port *prev;
182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 prev = NULL;
184
185 list_for_each_entry_rcu(p, &br->port_list, list) {
Vlad Yasevich867a5942013-06-05 10:08:01 -0400186 /* Do not flood unicast traffic to ports that turn it off */
187 if (unicast && !(p->flags & BR_FLOOD))
188 continue;
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 */
Vlad Yasevich867a5942013-06-05 10:08:01 -0400210void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, bool unicast)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211{
Vlad Yasevich867a5942013-06-05 10:08:01 -0400212 br_flood(br, skb, NULL, __br_deliver, unicast);
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,
Vlad Yasevich867a5942013-06-05 10:08:01 -0400217 struct sk_buff *skb2, bool unicast)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
Vlad Yasevich867a5942013-06-05 10:08:01 -0400219 br_flood(br, skb, skb2, __br_forward, unicast);
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
Eric Dumazete8051682010-11-15 06:38:10 +0000236 rp = rcu_dereference(hlist_first_rcu(&br->router_list));
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)
Eric Dumazete8051682010-11-15 06:38:10 +0000255 rp = rcu_dereference(hlist_next_rcu(rp));
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