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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 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 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 dev_queue_xmit(skb);
51 }
52
53 return 0;
54}
55
56int br_forward_finish(struct sk_buff *skb)
57{
58 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
59 br_dev_queue_push_xmit);
60
61}
62
63static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
64{
65 skb->dev = to->dev;
66
67 if (unlikely(netpoll_tx_running(to->dev))) {
68 if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
69 kfree_skb(skb);
70 else {
71 skb_push(skb, ETH_HLEN);
72 br_netpoll_send_skb(to, skb);
73 }
74 return;
75 }
76
77 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
78 br_forward_finish);
79}
80
81static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
82{
83 struct net_device *indev;
84
85 if (skb_warn_if_lro(skb)) {
86 kfree_skb(skb);
87 return;
88 }
89
90 indev = skb->dev;
91 skb->dev = to->dev;
92 skb_forward_csum(skb);
93
94 NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
95 br_forward_finish);
96}
97
98/* called with rcu_read_lock */
99void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
100{
101 if (should_deliver(to, skb)) {
102 __br_deliver(to, skb);
103 return;
104 }
105
106 kfree_skb(skb);
107}
108
109/* called with rcu_read_lock */
110void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
111{
112 if (should_deliver(to, skb)) {
113 if (skb0)
114 deliver_clone(to, skb, __br_forward);
115 else
116 __br_forward(to, skb);
117 return;
118 }
119
120 if (!skb0)
121 kfree_skb(skb);
122}
123
124static int deliver_clone(const struct net_bridge_port *prev,
125 struct sk_buff *skb,
126 void (*__packet_hook)(const struct net_bridge_port *p,
127 struct sk_buff *skb))
128{
129 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
130
131 skb = skb_clone(skb, GFP_ATOMIC);
132 if (!skb) {
133 dev->stats.tx_dropped++;
134 return -ENOMEM;
135 }
136
137 __packet_hook(prev, skb);
138 return 0;
139}
140
141static struct net_bridge_port *maybe_deliver(
142 struct net_bridge_port *prev, struct net_bridge_port *p,
143 struct sk_buff *skb,
144 void (*__packet_hook)(const struct net_bridge_port *p,
145 struct sk_buff *skb))
146{
147 int err;
148
149 if (!should_deliver(p, skb))
150 return prev;
151
152 if (!prev)
153 goto out;
154
155 err = deliver_clone(prev, skb, __packet_hook);
156 if (err)
157 return ERR_PTR(err);
158
159out:
160 return p;
161}
162
163/* called under bridge lock */
164static void br_flood(struct net_bridge *br, struct sk_buff *skb,
165 struct sk_buff *skb0,
166 void (*__packet_hook)(const struct net_bridge_port *p,
167 struct sk_buff *skb))
168{
169 struct net_bridge_port *p;
170 struct net_bridge_port *prev;
171
172 prev = NULL;
173
174 list_for_each_entry_rcu(p, &br->port_list, list) {
175 prev = maybe_deliver(prev, p, skb, __packet_hook);
176 if (IS_ERR(prev))
177 goto out;
178 }
179
180 if (!prev)
181 goto out;
182
183 if (skb0)
184 deliver_clone(prev, skb, __packet_hook);
185 else
186 __packet_hook(prev, skb);
187 return;
188
189out:
190 if (!skb0)
191 kfree_skb(skb);
192}
193
194
195/* called with rcu_read_lock */
196void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb)
197{
198 br_flood(br, skb, NULL, __br_deliver);
199}
200
201/* called under bridge lock */
202void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
203 struct sk_buff *skb2)
204{
205 br_flood(br, skb, skb2, __br_forward);
206}
207
208#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
209/* called with rcu_read_lock */
210static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
211 struct sk_buff *skb, struct sk_buff *skb0,
212 void (*__packet_hook)(
213 const struct net_bridge_port *p,
214 struct sk_buff *skb))
215{
216 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
217 struct net_bridge *br = netdev_priv(dev);
218 struct net_bridge_port *prev = NULL;
219 struct net_bridge_port_group *p;
220 struct hlist_node *rp;
221
222 rp = rcu_dereference(hlist_first_rcu(&br->router_list));
223 p = mdst ? rcu_dereference(mdst->ports) : NULL;
224 while (p || rp) {
225 struct net_bridge_port *port, *lport, *rport;
226
227 lport = p ? p->port : NULL;
228 rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
229 NULL;
230
231 port = (unsigned long)lport > (unsigned long)rport ?
232 lport : rport;
233
234 prev = maybe_deliver(prev, port, skb, __packet_hook);
235 if (IS_ERR(prev))
236 goto out;
237
238 if ((unsigned long)lport >= (unsigned long)port)
239 p = rcu_dereference(p->next);
240 if ((unsigned long)rport >= (unsigned long)port)
241 rp = rcu_dereference(hlist_next_rcu(rp));
242 }
243
244 if (!prev)
245 goto out;
246
247 if (skb0)
248 deliver_clone(prev, skb, __packet_hook);
249 else
250 __packet_hook(prev, skb);
251 return;
252
253out:
254 if (!skb0)
255 kfree_skb(skb);
256}
257
258/* called with rcu_read_lock */
259void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
260 struct sk_buff *skb)
261{
262 br_multicast_flood(mdst, skb, NULL, __br_deliver);
263}
264
265/* called with rcu_read_lock */
266void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
267 struct sk_buff *skb, struct sk_buff *skb2)
268{
269 br_multicast_flood(mdst, skb, skb2, __br_forward);
270}
271#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
24/* Don't forward packets to originating port or forwarding disabled */
25static inline int should_deliver(const struct net_bridge_port *p,
26 const struct sk_buff *skb)
27{
28 struct net_bridge_vlan_group *vg;
29
30 vg = nbp_vlan_group_rcu(p);
31 return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
32 br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING &&
33 nbp_switchdev_allowed_egress(p, skb);
34}
35
36int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
37{
38 if (!is_skb_forwardable(skb->dev, skb))
39 goto drop;
40
41 skb_push(skb, ETH_HLEN);
42 br_drop_fake_rtable(skb);
43
44 if (skb->ip_summed == CHECKSUM_PARTIAL &&
45 (skb->protocol == htons(ETH_P_8021Q) ||
46 skb->protocol == htons(ETH_P_8021AD))) {
47 int depth;
48
49 if (!__vlan_get_protocol(skb, skb->protocol, &depth))
50 goto drop;
51
52 skb_set_network_header(skb, depth);
53 }
54
55 dev_queue_xmit(skb);
56
57 return 0;
58
59drop:
60 kfree_skb(skb);
61 return 0;
62}
63EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
64
65int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
66{
67 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
68 net, sk, skb, NULL, skb->dev,
69 br_dev_queue_push_xmit);
70
71}
72EXPORT_SYMBOL_GPL(br_forward_finish);
73
74static void __br_forward(const struct net_bridge_port *to,
75 struct sk_buff *skb, bool local_orig)
76{
77 struct net_bridge_vlan_group *vg;
78 struct net_device *indev;
79 struct net *net;
80 int br_hook;
81
82 vg = nbp_vlan_group_rcu(to);
83 skb = br_handle_vlan(to->br, to, vg, skb);
84 if (!skb)
85 return;
86
87 indev = skb->dev;
88 skb->dev = to->dev;
89 if (!local_orig) {
90 if (skb_warn_if_lro(skb)) {
91 kfree_skb(skb);
92 return;
93 }
94 br_hook = NF_BR_FORWARD;
95 skb_forward_csum(skb);
96 net = dev_net(indev);
97 } else {
98 if (unlikely(netpoll_tx_running(to->br->dev))) {
99 if (!is_skb_forwardable(skb->dev, skb)) {
100 kfree_skb(skb);
101 } else {
102 skb_push(skb, ETH_HLEN);
103 br_netpoll_send_skb(to, skb);
104 }
105 return;
106 }
107 br_hook = NF_BR_LOCAL_OUT;
108 net = dev_net(skb->dev);
109 indev = NULL;
110 }
111
112 NF_HOOK(NFPROTO_BRIDGE, br_hook,
113 net, NULL, skb, indev, skb->dev,
114 br_forward_finish);
115}
116
117static int deliver_clone(const struct net_bridge_port *prev,
118 struct sk_buff *skb, bool local_orig)
119{
120 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
121
122 skb = skb_clone(skb, GFP_ATOMIC);
123 if (!skb) {
124 dev->stats.tx_dropped++;
125 return -ENOMEM;
126 }
127
128 __br_forward(prev, skb, local_orig);
129 return 0;
130}
131
132/**
133 * br_forward - forward a packet to a specific port
134 * @to: destination port
135 * @skb: packet being forwarded
136 * @local_rcv: packet will be received locally after forwarding
137 * @local_orig: packet is locally originated
138 *
139 * Should be called with rcu_read_lock.
140 */
141void br_forward(const struct net_bridge_port *to,
142 struct sk_buff *skb, bool local_rcv, bool local_orig)
143{
144 if (to && should_deliver(to, skb)) {
145 if (local_rcv)
146 deliver_clone(to, skb, local_orig);
147 else
148 __br_forward(to, skb, local_orig);
149 return;
150 }
151
152 if (!local_rcv)
153 kfree_skb(skb);
154}
155EXPORT_SYMBOL_GPL(br_forward);
156
157static struct net_bridge_port *maybe_deliver(
158 struct net_bridge_port *prev, struct net_bridge_port *p,
159 struct sk_buff *skb, bool local_orig)
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, local_orig);
170 if (err)
171 return ERR_PTR(err);
172
173out:
174 return p;
175}
176
177/* called under rcu_read_lock */
178void br_flood(struct net_bridge *br, struct sk_buff *skb,
179 enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
180{
181 u8 igmp_type = br_multicast_igmp_type(skb);
182 struct net_bridge_port *prev = NULL;
183 struct net_bridge_port *p;
184
185 list_for_each_entry_rcu(p, &br->port_list, list) {
186 /* Do not flood unicast traffic to ports that turn it off, nor
187 * other traffic if flood off, except for traffic we originate
188 */
189 switch (pkt_type) {
190 case BR_PKT_UNICAST:
191 if (!(p->flags & BR_FLOOD))
192 continue;
193 break;
194 case BR_PKT_MULTICAST:
195 if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
196 continue;
197 break;
198 case BR_PKT_BROADCAST:
199 if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
200 continue;
201 break;
202 }
203
204 /* Do not flood to ports that enable proxy ARP */
205 if (p->flags & BR_PROXYARP)
206 continue;
207 if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) &&
208 BR_INPUT_SKB_CB(skb)->proxyarp_replied)
209 continue;
210
211 prev = maybe_deliver(prev, p, skb, local_orig);
212 if (IS_ERR(prev))
213 goto out;
214 if (prev == p)
215 br_multicast_count(p->br, p, skb, igmp_type,
216 BR_MCAST_DIR_TX);
217 }
218
219 if (!prev)
220 goto out;
221
222 if (local_rcv)
223 deliver_clone(prev, skb, local_orig);
224 else
225 __br_forward(prev, skb, local_orig);
226 return;
227
228out:
229 if (!local_rcv)
230 kfree_skb(skb);
231}
232
233#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
234static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
235 const unsigned char *addr, bool local_orig)
236{
237 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
238 const unsigned char *src = eth_hdr(skb)->h_source;
239
240 if (!should_deliver(p, skb))
241 return;
242
243 /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
244 if (skb->dev == p->dev && ether_addr_equal(src, addr))
245 return;
246
247 skb = skb_copy(skb, GFP_ATOMIC);
248 if (!skb) {
249 dev->stats.tx_dropped++;
250 return;
251 }
252
253 if (!is_broadcast_ether_addr(addr))
254 memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
255
256 __br_forward(p, skb, local_orig);
257}
258
259/* called with rcu_read_lock */
260void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
261 struct sk_buff *skb,
262 bool local_rcv, bool local_orig)
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 struct net_bridge_port_group *p;
269 struct hlist_node *rp;
270
271 rp = rcu_dereference(hlist_first_rcu(&br->router_list));
272 p = mdst ? rcu_dereference(mdst->ports) : NULL;
273 while (p || rp) {
274 struct net_bridge_port *port, *lport, *rport;
275
276 lport = p ? p->port : NULL;
277 rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
278 NULL;
279
280 if ((unsigned long)lport > (unsigned long)rport) {
281 port = lport;
282
283 if (port->flags & BR_MULTICAST_TO_UNICAST) {
284 maybe_deliver_addr(lport, skb, p->eth_addr,
285 local_orig);
286 goto delivered;
287 }
288 } else {
289 port = rport;
290 }
291
292 prev = maybe_deliver(prev, port, skb, local_orig);
293delivered:
294 if (IS_ERR(prev))
295 goto out;
296 if (prev == port)
297 br_multicast_count(port->br, port, skb, igmp_type,
298 BR_MCAST_DIR_TX);
299
300 if ((unsigned long)lport >= (unsigned long)port)
301 p = rcu_dereference(p->next);
302 if ((unsigned long)rport >= (unsigned long)port)
303 rp = rcu_dereference(hlist_next_rcu(rp));
304 }
305
306 if (!prev)
307 goto out;
308
309 if (local_rcv)
310 deliver_clone(prev, skb, local_orig);
311 else
312 __br_forward(prev, skb, local_orig);
313 return;
314
315out:
316 if (!local_rcv)
317 kfree_skb(skb);
318}
319#endif