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1/*
2 * Forwarding decision
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
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
14#include <linux/err.h>
15#include <linux/slab.h>
16#include <linux/kernel.h>
17#include <linux/netdevice.h>
18#include <linux/netpoll.h>
19#include <linux/skbuff.h>
20#include <linux/if_vlan.h>
21#include <linux/netfilter_bridge.h>
22#include "br_private.h"
23
24static int deliver_clone(const struct net_bridge_port *prev,
25 struct sk_buff *skb,
26 void (*__packet_hook)(const struct net_bridge_port *p,
27 struct sk_buff *skb));
28
29/* Don't forward packets to originating port or forwarding disabled */
30static inline int should_deliver(const struct net_bridge_port *p,
31 const struct sk_buff *skb)
32{
33 struct net_bridge_vlan_group *vg;
34
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;
38}
39
40int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
41{
42 if (!is_skb_forwardable(skb->dev, skb))
43 goto drop;
44
45 skb_push(skb, ETH_HLEN);
46 br_drop_fake_rtable(skb);
47
48 if (skb->ip_summed == CHECKSUM_PARTIAL &&
49 (skb->protocol == htons(ETH_P_8021Q) ||
50 skb->protocol == htons(ETH_P_8021AD))) {
51 int depth;
52
53 if (!__vlan_get_protocol(skb, skb->protocol, &depth))
54 goto drop;
55
56 skb_set_network_header(skb, depth);
57 }
58
59 dev_queue_xmit(skb);
60
61 return 0;
62
63drop:
64 kfree_skb(skb);
65 return 0;
66}
67EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
68
69int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
70{
71 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
72 net, sk, skb, NULL, skb->dev,
73 br_dev_queue_push_xmit);
74
75}
76EXPORT_SYMBOL_GPL(br_forward_finish);
77
78static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
79{
80 struct net_bridge_vlan_group *vg;
81
82 vg = nbp_vlan_group_rcu(to);
83 skb = br_handle_vlan(to->br, vg, skb);
84 if (!skb)
85 return;
86
87 skb->dev = to->dev;
88
89 if (unlikely(netpoll_tx_running(to->br->dev))) {
90 if (!is_skb_forwardable(skb->dev, skb))
91 kfree_skb(skb);
92 else {
93 skb_push(skb, ETH_HLEN);
94 br_netpoll_send_skb(to, skb);
95 }
96 return;
97 }
98
99 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT,
100 dev_net(skb->dev), NULL, skb,NULL, skb->dev,
101 br_forward_finish);
102}
103
104static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
105{
106 struct net_bridge_vlan_group *vg;
107 struct net_device *indev;
108
109 if (skb_warn_if_lro(skb)) {
110 kfree_skb(skb);
111 return;
112 }
113
114 vg = nbp_vlan_group_rcu(to);
115 skb = br_handle_vlan(to->br, vg, skb);
116 if (!skb)
117 return;
118
119 indev = skb->dev;
120 skb->dev = to->dev;
121 skb_forward_csum(skb);
122
123 NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD,
124 dev_net(indev), NULL, skb, indev, skb->dev,
125 br_forward_finish);
126}
127
128/* called with rcu_read_lock */
129void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
130{
131 if (to && should_deliver(to, skb)) {
132 __br_deliver(to, skb);
133 return;
134 }
135
136 kfree_skb(skb);
137}
138EXPORT_SYMBOL_GPL(br_deliver);
139
140/* called with rcu_read_lock */
141void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
142{
143 if (to && should_deliver(to, skb)) {
144 if (skb0)
145 deliver_clone(to, skb, __br_forward);
146 else
147 __br_forward(to, skb);
148 return;
149 }
150
151 if (!skb0)
152 kfree_skb(skb);
153}
154
155static int deliver_clone(const struct net_bridge_port *prev,
156 struct sk_buff *skb,
157 void (*__packet_hook)(const struct net_bridge_port *p,
158 struct sk_buff *skb))
159{
160 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
161
162 skb = skb_clone(skb, GFP_ATOMIC);
163 if (!skb) {
164 dev->stats.tx_dropped++;
165 return -ENOMEM;
166 }
167
168 __packet_hook(prev, skb);
169 return 0;
170}
171
172static struct net_bridge_port *maybe_deliver(
173 struct net_bridge_port *prev, struct net_bridge_port *p,
174 struct sk_buff *skb,
175 void (*__packet_hook)(const struct net_bridge_port *p,
176 struct sk_buff *skb))
177{
178 int err;
179
180 if (!should_deliver(p, skb))
181 return prev;
182
183 if (!prev)
184 goto out;
185
186 err = deliver_clone(prev, skb, __packet_hook);
187 if (err)
188 return ERR_PTR(err);
189
190out:
191 return p;
192}
193
194/* called under bridge lock */
195static void br_flood(struct net_bridge *br, struct sk_buff *skb,
196 struct sk_buff *skb0,
197 void (*__packet_hook)(const struct net_bridge_port *p,
198 struct sk_buff *skb),
199 bool unicast)
200{
201 struct net_bridge_port *p;
202 struct net_bridge_port *prev;
203
204 prev = NULL;
205
206 list_for_each_entry_rcu(p, &br->port_list, list) {
207 /* Do not flood unicast traffic to ports that turn it off */
208 if (unicast && !(p->flags & BR_FLOOD))
209 continue;
210
211 /* Do not flood to ports that enable proxy ARP */
212 if (p->flags & BR_PROXYARP)
213 continue;
214 if ((p->flags & BR_PROXYARP_WIFI) &&
215 BR_INPUT_SKB_CB(skb)->proxyarp_replied)
216 continue;
217
218 prev = maybe_deliver(prev, p, skb, __packet_hook);
219 if (IS_ERR(prev))
220 goto out;
221 }
222
223 if (!prev)
224 goto out;
225
226 if (skb0)
227 deliver_clone(prev, skb, __packet_hook);
228 else
229 __packet_hook(prev, skb);
230 return;
231
232out:
233 if (!skb0)
234 kfree_skb(skb);
235}
236
237
238/* called with rcu_read_lock */
239void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, bool unicast)
240{
241 br_flood(br, skb, NULL, __br_deliver, unicast);
242}
243
244/* called under bridge lock */
245void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
246 struct sk_buff *skb2, bool unicast)
247{
248 br_flood(br, skb, skb2, __br_forward, unicast);
249}
250
251#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
252/* called with rcu_read_lock */
253static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
254 struct sk_buff *skb, struct sk_buff *skb0,
255 void (*__packet_hook)(
256 const struct net_bridge_port *p,
257 struct sk_buff *skb))
258{
259 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
260 struct net_bridge *br = netdev_priv(dev);
261 struct net_bridge_port *prev = NULL;
262 struct net_bridge_port_group *p;
263 struct hlist_node *rp;
264
265 rp = rcu_dereference(hlist_first_rcu(&br->router_list));
266 p = mdst ? rcu_dereference(mdst->ports) : NULL;
267 while (p || rp) {
268 struct net_bridge_port *port, *lport, *rport;
269
270 lport = p ? p->port : NULL;
271 rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
272 NULL;
273
274 port = (unsigned long)lport > (unsigned long)rport ?
275 lport : rport;
276
277 prev = maybe_deliver(prev, port, skb, __packet_hook);
278 if (IS_ERR(prev))
279 goto out;
280
281 if ((unsigned long)lport >= (unsigned long)port)
282 p = rcu_dereference(p->next);
283 if ((unsigned long)rport >= (unsigned long)port)
284 rp = rcu_dereference(hlist_next_rcu(rp));
285 }
286
287 if (!prev)
288 goto out;
289
290 if (skb0)
291 deliver_clone(prev, skb, __packet_hook);
292 else
293 __packet_hook(prev, skb);
294 return;
295
296out:
297 if (!skb0)
298 kfree_skb(skb);
299}
300
301/* called with rcu_read_lock */
302void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
303 struct sk_buff *skb)
304{
305 br_multicast_flood(mdst, skb, NULL, __br_deliver);
306}
307
308/* called with rcu_read_lock */
309void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
310 struct sk_buff *skb, struct sk_buff *skb2)
311{
312 br_multicast_flood(mdst, skb, skb2, __br_forward);
313}
314#endif
1/*
2 * Forwarding decision
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
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
14#include <linux/err.h>
15#include <linux/slab.h>
16#include <linux/kernel.h>
17#include <linux/netdevice.h>
18#include <linux/netpoll.h>
19#include <linux/skbuff.h>
20#include <linux/if_vlan.h>
21#include <linux/netfilter_bridge.h>
22#include "br_private.h"
23
24static int deliver_clone(const struct net_bridge_port *prev,
25 struct sk_buff *skb,
26 void (*__packet_hook)(const struct net_bridge_port *p,
27 struct sk_buff *skb));
28
29/* Don't forward packets to originating port or forwarding diasabled */
30static inline int should_deliver(const struct net_bridge_port *p,
31 const struct sk_buff *skb)
32{
33 return (((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
34 p->state == BR_STATE_FORWARDING);
35}
36
37static inline unsigned int packet_length(const struct sk_buff *skb)
38{
39 return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
40}
41
42int br_dev_queue_push_xmit(struct sk_buff *skb)
43{
44 /* ip_fragment doesn't copy the MAC header */
45 if (nf_bridge_maybe_copy_header(skb) ||
46 (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))) {
47 kfree_skb(skb);
48 } else {
49 skb_push(skb, ETH_HLEN);
50 br_drop_fake_rtable(skb);
51 dev_queue_xmit(skb);
52 }
53
54 return 0;
55}
56
57int br_forward_finish(struct sk_buff *skb)
58{
59 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
60 br_dev_queue_push_xmit);
61
62}
63
64static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
65{
66 skb->dev = to->dev;
67
68 if (unlikely(netpoll_tx_running(to->dev))) {
69 if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
70 kfree_skb(skb);
71 else {
72 skb_push(skb, ETH_HLEN);
73 br_netpoll_send_skb(to, skb);
74 }
75 return;
76 }
77
78 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
79 br_forward_finish);
80}
81
82static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
83{
84 struct net_device *indev;
85
86 if (skb_warn_if_lro(skb)) {
87 kfree_skb(skb);
88 return;
89 }
90
91 indev = skb->dev;
92 skb->dev = to->dev;
93 skb_forward_csum(skb);
94
95 NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
96 br_forward_finish);
97}
98
99/* called with rcu_read_lock */
100void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
101{
102 if (to && should_deliver(to, skb)) {
103 __br_deliver(to, skb);
104 return;
105 }
106
107 kfree_skb(skb);
108}
109
110/* called with rcu_read_lock */
111void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
112{
113 if (should_deliver(to, skb)) {
114 if (skb0)
115 deliver_clone(to, skb, __br_forward);
116 else
117 __br_forward(to, skb);
118 return;
119 }
120
121 if (!skb0)
122 kfree_skb(skb);
123}
124
125static int deliver_clone(const struct net_bridge_port *prev,
126 struct sk_buff *skb,
127 void (*__packet_hook)(const struct net_bridge_port *p,
128 struct sk_buff *skb))
129{
130 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
131
132 skb = skb_clone(skb, GFP_ATOMIC);
133 if (!skb) {
134 dev->stats.tx_dropped++;
135 return -ENOMEM;
136 }
137
138 __packet_hook(prev, skb);
139 return 0;
140}
141
142static struct net_bridge_port *maybe_deliver(
143 struct net_bridge_port *prev, struct net_bridge_port *p,
144 struct sk_buff *skb,
145 void (*__packet_hook)(const struct net_bridge_port *p,
146 struct sk_buff *skb))
147{
148 int err;
149
150 if (!should_deliver(p, skb))
151 return prev;
152
153 if (!prev)
154 goto out;
155
156 err = deliver_clone(prev, skb, __packet_hook);
157 if (err)
158 return ERR_PTR(err);
159
160out:
161 return p;
162}
163
164/* called under bridge lock */
165static void br_flood(struct net_bridge *br, struct sk_buff *skb,
166 struct sk_buff *skb0,
167 void (*__packet_hook)(const struct net_bridge_port *p,
168 struct sk_buff *skb))
169{
170 struct net_bridge_port *p;
171 struct net_bridge_port *prev;
172
173 prev = NULL;
174
175 list_for_each_entry_rcu(p, &br->port_list, list) {
176 prev = maybe_deliver(prev, p, skb, __packet_hook);
177 if (IS_ERR(prev))
178 goto out;
179 }
180
181 if (!prev)
182 goto out;
183
184 if (skb0)
185 deliver_clone(prev, skb, __packet_hook);
186 else
187 __packet_hook(prev, skb);
188 return;
189
190out:
191 if (!skb0)
192 kfree_skb(skb);
193}
194
195
196/* called with rcu_read_lock */
197void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb)
198{
199 br_flood(br, skb, NULL, __br_deliver);
200}
201
202/* called under bridge lock */
203void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
204 struct sk_buff *skb2)
205{
206 br_flood(br, skb, skb2, __br_forward);
207}
208
209#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
210/* called with rcu_read_lock */
211static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
212 struct sk_buff *skb, struct sk_buff *skb0,
213 void (*__packet_hook)(
214 const struct net_bridge_port *p,
215 struct sk_buff *skb))
216{
217 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
218 struct net_bridge *br = netdev_priv(dev);
219 struct net_bridge_port *prev = NULL;
220 struct net_bridge_port_group *p;
221 struct hlist_node *rp;
222
223 rp = rcu_dereference(hlist_first_rcu(&br->router_list));
224 p = mdst ? rcu_dereference(mdst->ports) : NULL;
225 while (p || rp) {
226 struct net_bridge_port *port, *lport, *rport;
227
228 lport = p ? p->port : NULL;
229 rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
230 NULL;
231
232 port = (unsigned long)lport > (unsigned long)rport ?
233 lport : rport;
234
235 prev = maybe_deliver(prev, port, skb, __packet_hook);
236 if (IS_ERR(prev))
237 goto out;
238
239 if ((unsigned long)lport >= (unsigned long)port)
240 p = rcu_dereference(p->next);
241 if ((unsigned long)rport >= (unsigned long)port)
242 rp = rcu_dereference(hlist_next_rcu(rp));
243 }
244
245 if (!prev)
246 goto out;
247
248 if (skb0)
249 deliver_clone(prev, skb, __packet_hook);
250 else
251 __packet_hook(prev, skb);
252 return;
253
254out:
255 if (!skb0)
256 kfree_skb(skb);
257}
258
259/* called with rcu_read_lock */
260void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
261 struct sk_buff *skb)
262{
263 br_multicast_flood(mdst, skb, NULL, __br_deliver);
264}
265
266/* called with rcu_read_lock */
267void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
268 struct sk_buff *skb, struct sk_buff *skb2)
269{
270 br_multicast_flood(mdst, skb, skb2, __br_forward);
271}
272#endif