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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Forwarding decision
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9
10#include <linux/err.h>
11#include <linux/slab.h>
12#include <linux/kernel.h>
13#include <linux/netdevice.h>
14#include <linux/netpoll.h>
15#include <linux/skbuff.h>
16#include <linux/if_vlan.h>
17#include <linux/netfilter_bridge.h>
18#include "br_private.h"
19
20/* Don't forward packets to originating port or forwarding disabled */
21static inline int should_deliver(const struct net_bridge_port *p,
22 const struct sk_buff *skb)
23{
24 struct net_bridge_vlan_group *vg;
25
26 vg = nbp_vlan_group_rcu(p);
27 return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
28 p->state == BR_STATE_FORWARDING && br_allowed_egress(vg, skb) &&
29 nbp_switchdev_allowed_egress(p, skb) &&
30 !br_skb_isolated(p, skb);
31}
32
33int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
34{
35 skb_push(skb, ETH_HLEN);
36 if (!is_skb_forwardable(skb->dev, skb))
37 goto drop;
38
39 br_drop_fake_rtable(skb);
40
41 if (skb->ip_summed == CHECKSUM_PARTIAL &&
42 (skb->protocol == htons(ETH_P_8021Q) ||
43 skb->protocol == htons(ETH_P_8021AD))) {
44 int depth;
45
46 if (!__vlan_get_protocol(skb, skb->protocol, &depth))
47 goto drop;
48
49 skb_set_network_header(skb, depth);
50 }
51
52 dev_queue_xmit(skb);
53
54 return 0;
55
56drop:
57 kfree_skb(skb);
58 return 0;
59}
60EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
61
62int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
63{
64 skb->tstamp = 0;
65 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
66 net, sk, skb, NULL, skb->dev,
67 br_dev_queue_push_xmit);
68
69}
70EXPORT_SYMBOL_GPL(br_forward_finish);
71
72static void __br_forward(const struct net_bridge_port *to,
73 struct sk_buff *skb, bool local_orig)
74{
75 struct net_bridge_vlan_group *vg;
76 struct net_device *indev;
77 struct net *net;
78 int br_hook;
79
80 vg = nbp_vlan_group_rcu(to);
81 skb = br_handle_vlan(to->br, to, vg, skb);
82 if (!skb)
83 return;
84
85 indev = skb->dev;
86 skb->dev = to->dev;
87 if (!local_orig) {
88 if (skb_warn_if_lro(skb)) {
89 kfree_skb(skb);
90 return;
91 }
92 br_hook = NF_BR_FORWARD;
93 skb_forward_csum(skb);
94 net = dev_net(indev);
95 } else {
96 if (unlikely(netpoll_tx_running(to->br->dev))) {
97 skb_push(skb, ETH_HLEN);
98 if (!is_skb_forwardable(skb->dev, skb))
99 kfree_skb(skb);
100 else
101 br_netpoll_send_skb(to, skb);
102 return;
103 }
104 br_hook = NF_BR_LOCAL_OUT;
105 net = dev_net(skb->dev);
106 indev = NULL;
107 }
108
109 NF_HOOK(NFPROTO_BRIDGE, br_hook,
110 net, NULL, skb, indev, skb->dev,
111 br_forward_finish);
112}
113
114static int deliver_clone(const struct net_bridge_port *prev,
115 struct sk_buff *skb, bool local_orig)
116{
117 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
118
119 skb = skb_clone(skb, GFP_ATOMIC);
120 if (!skb) {
121 dev->stats.tx_dropped++;
122 return -ENOMEM;
123 }
124
125 __br_forward(prev, skb, local_orig);
126 return 0;
127}
128
129/**
130 * br_forward - forward a packet to a specific port
131 * @to: destination port
132 * @skb: packet being forwarded
133 * @local_rcv: packet will be received locally after forwarding
134 * @local_orig: packet is locally originated
135 *
136 * Should be called with rcu_read_lock.
137 */
138void br_forward(const struct net_bridge_port *to,
139 struct sk_buff *skb, bool local_rcv, bool local_orig)
140{
141 if (unlikely(!to))
142 goto out;
143
144 /* redirect to backup link if the destination port is down */
145 if (rcu_access_pointer(to->backup_port) && !netif_carrier_ok(to->dev)) {
146 struct net_bridge_port *backup_port;
147
148 backup_port = rcu_dereference(to->backup_port);
149 if (unlikely(!backup_port))
150 goto out;
151 to = backup_port;
152 }
153
154 if (should_deliver(to, skb)) {
155 if (local_rcv)
156 deliver_clone(to, skb, local_orig);
157 else
158 __br_forward(to, skb, local_orig);
159 return;
160 }
161
162out:
163 if (!local_rcv)
164 kfree_skb(skb);
165}
166EXPORT_SYMBOL_GPL(br_forward);
167
168static struct net_bridge_port *maybe_deliver(
169 struct net_bridge_port *prev, struct net_bridge_port *p,
170 struct sk_buff *skb, bool local_orig)
171{
172 u8 igmp_type = br_multicast_igmp_type(skb);
173 int err;
174
175 if (!should_deliver(p, skb))
176 return prev;
177
178 if (!prev)
179 goto out;
180
181 err = deliver_clone(prev, skb, local_orig);
182 if (err)
183 return ERR_PTR(err);
184out:
185 br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX);
186
187 return p;
188}
189
190/* called under rcu_read_lock */
191void br_flood(struct net_bridge *br, struct sk_buff *skb,
192 enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
193{
194 struct net_bridge_port *prev = NULL;
195 struct net_bridge_port *p;
196
197 list_for_each_entry_rcu(p, &br->port_list, list) {
198 /* Do not flood unicast traffic to ports that turn it off, nor
199 * other traffic if flood off, except for traffic we originate
200 */
201 switch (pkt_type) {
202 case BR_PKT_UNICAST:
203 if (!(p->flags & BR_FLOOD))
204 continue;
205 break;
206 case BR_PKT_MULTICAST:
207 if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
208 continue;
209 break;
210 case BR_PKT_BROADCAST:
211 if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
212 continue;
213 break;
214 }
215
216 /* Do not flood to ports that enable proxy ARP */
217 if (p->flags & BR_PROXYARP)
218 continue;
219 if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) &&
220 BR_INPUT_SKB_CB(skb)->proxyarp_replied)
221 continue;
222
223 prev = maybe_deliver(prev, p, skb, local_orig);
224 if (IS_ERR(prev))
225 goto out;
226 }
227
228 if (!prev)
229 goto out;
230
231 if (local_rcv)
232 deliver_clone(prev, skb, local_orig);
233 else
234 __br_forward(prev, skb, local_orig);
235 return;
236
237out:
238 if (!local_rcv)
239 kfree_skb(skb);
240}
241
242#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
243static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
244 const unsigned char *addr, bool local_orig)
245{
246 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
247 const unsigned char *src = eth_hdr(skb)->h_source;
248
249 if (!should_deliver(p, skb))
250 return;
251
252 /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
253 if (skb->dev == p->dev && ether_addr_equal(src, addr))
254 return;
255
256 skb = skb_copy(skb, GFP_ATOMIC);
257 if (!skb) {
258 dev->stats.tx_dropped++;
259 return;
260 }
261
262 if (!is_broadcast_ether_addr(addr))
263 memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
264
265 __br_forward(p, skb, local_orig);
266}
267
268/* called with rcu_read_lock */
269void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
270 struct sk_buff *skb,
271 bool local_rcv, bool local_orig)
272{
273 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
274 struct net_bridge *br = netdev_priv(dev);
275 struct net_bridge_port *prev = NULL;
276 struct net_bridge_port_group *p;
277 struct hlist_node *rp;
278
279 rp = rcu_dereference(hlist_first_rcu(&br->router_list));
280 p = mdst ? rcu_dereference(mdst->ports) : NULL;
281 while (p || rp) {
282 struct net_bridge_port *port, *lport, *rport;
283
284 lport = p ? p->port : NULL;
285 rport = hlist_entry_safe(rp, struct net_bridge_port, rlist);
286
287 if ((unsigned long)lport > (unsigned long)rport) {
288 port = lport;
289
290 if (port->flags & BR_MULTICAST_TO_UNICAST) {
291 maybe_deliver_addr(lport, skb, p->eth_addr,
292 local_orig);
293 goto delivered;
294 }
295 } else {
296 port = rport;
297 }
298
299 prev = maybe_deliver(prev, port, skb, local_orig);
300 if (IS_ERR(prev))
301 goto out;
302delivered:
303 if ((unsigned long)lport >= (unsigned long)port)
304 p = rcu_dereference(p->next);
305 if ((unsigned long)rport >= (unsigned long)port)
306 rp = rcu_dereference(hlist_next_rcu(rp));
307 }
308
309 if (!prev)
310 goto out;
311
312 if (local_rcv)
313 deliver_clone(prev, skb, local_orig);
314 else
315 __br_forward(prev, skb, local_orig);
316 return;
317
318out:
319 if (!local_rcv)
320 kfree_skb(skb);
321}
322#endif
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Forwarding decision
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9
10#include <linux/err.h>
11#include <linux/slab.h>
12#include <linux/kernel.h>
13#include <linux/netdevice.h>
14#include <linux/netpoll.h>
15#include <linux/skbuff.h>
16#include <linux/if_vlan.h>
17#include <linux/netfilter_bridge.h>
18#include "br_private.h"
19
20/* Don't forward packets to originating port or forwarding disabled */
21static inline int should_deliver(const struct net_bridge_port *p,
22 const struct sk_buff *skb)
23{
24 struct net_bridge_vlan_group *vg;
25
26 vg = nbp_vlan_group_rcu(p);
27 return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
28 p->state == BR_STATE_FORWARDING && br_allowed_egress(vg, skb) &&
29 nbp_switchdev_allowed_egress(p, skb) &&
30 !br_skb_isolated(p, skb);
31}
32
33int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
34{
35 skb_push(skb, ETH_HLEN);
36 if (!is_skb_forwardable(skb->dev, skb))
37 goto drop;
38
39 br_drop_fake_rtable(skb);
40
41 if (skb->ip_summed == CHECKSUM_PARTIAL &&
42 eth_type_vlan(skb->protocol)) {
43 int depth;
44
45 if (!__vlan_get_protocol(skb, skb->protocol, &depth))
46 goto drop;
47
48 skb_set_network_header(skb, depth);
49 }
50
51 dev_queue_xmit(skb);
52
53 return 0;
54
55drop:
56 kfree_skb(skb);
57 return 0;
58}
59EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
60
61int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
62{
63 skb->tstamp = 0;
64 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
65 net, sk, skb, NULL, skb->dev,
66 br_dev_queue_push_xmit);
67
68}
69EXPORT_SYMBOL_GPL(br_forward_finish);
70
71static void __br_forward(const struct net_bridge_port *to,
72 struct sk_buff *skb, bool local_orig)
73{
74 struct net_bridge_vlan_group *vg;
75 struct net_device *indev;
76 struct net *net;
77 int br_hook;
78
79 vg = nbp_vlan_group_rcu(to);
80 skb = br_handle_vlan(to->br, to, vg, skb);
81 if (!skb)
82 return;
83
84 indev = skb->dev;
85 skb->dev = to->dev;
86 if (!local_orig) {
87 if (skb_warn_if_lro(skb)) {
88 kfree_skb(skb);
89 return;
90 }
91 br_hook = NF_BR_FORWARD;
92 skb_forward_csum(skb);
93 net = dev_net(indev);
94 } else {
95 if (unlikely(netpoll_tx_running(to->br->dev))) {
96 skb_push(skb, ETH_HLEN);
97 if (!is_skb_forwardable(skb->dev, skb))
98 kfree_skb(skb);
99 else
100 br_netpoll_send_skb(to, skb);
101 return;
102 }
103 br_hook = NF_BR_LOCAL_OUT;
104 net = dev_net(skb->dev);
105 indev = NULL;
106 }
107
108 NF_HOOK(NFPROTO_BRIDGE, br_hook,
109 net, NULL, skb, indev, skb->dev,
110 br_forward_finish);
111}
112
113static int deliver_clone(const struct net_bridge_port *prev,
114 struct sk_buff *skb, bool local_orig)
115{
116 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
117
118 skb = skb_clone(skb, GFP_ATOMIC);
119 if (!skb) {
120 dev->stats.tx_dropped++;
121 return -ENOMEM;
122 }
123
124 __br_forward(prev, skb, local_orig);
125 return 0;
126}
127
128/**
129 * br_forward - forward a packet to a specific port
130 * @to: destination port
131 * @skb: packet being forwarded
132 * @local_rcv: packet will be received locally after forwarding
133 * @local_orig: packet is locally originated
134 *
135 * Should be called with rcu_read_lock.
136 */
137void br_forward(const struct net_bridge_port *to,
138 struct sk_buff *skb, bool local_rcv, bool local_orig)
139{
140 if (unlikely(!to))
141 goto out;
142
143 /* redirect to backup link if the destination port is down */
144 if (rcu_access_pointer(to->backup_port) && !netif_carrier_ok(to->dev)) {
145 struct net_bridge_port *backup_port;
146
147 backup_port = rcu_dereference(to->backup_port);
148 if (unlikely(!backup_port))
149 goto out;
150 to = backup_port;
151 }
152
153 if (should_deliver(to, skb)) {
154 if (local_rcv)
155 deliver_clone(to, skb, local_orig);
156 else
157 __br_forward(to, skb, local_orig);
158 return;
159 }
160
161out:
162 if (!local_rcv)
163 kfree_skb(skb);
164}
165EXPORT_SYMBOL_GPL(br_forward);
166
167static struct net_bridge_port *maybe_deliver(
168 struct net_bridge_port *prev, struct net_bridge_port *p,
169 struct sk_buff *skb, bool local_orig)
170{
171 u8 igmp_type = br_multicast_igmp_type(skb);
172 int err;
173
174 if (!should_deliver(p, skb))
175 return prev;
176
177 if (!prev)
178 goto out;
179
180 err = deliver_clone(prev, skb, local_orig);
181 if (err)
182 return ERR_PTR(err);
183out:
184 br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX);
185
186 return p;
187}
188
189/* called under rcu_read_lock */
190void br_flood(struct net_bridge *br, struct sk_buff *skb,
191 enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
192{
193 struct net_bridge_port *prev = NULL;
194 struct net_bridge_port *p;
195
196 list_for_each_entry_rcu(p, &br->port_list, list) {
197 /* Do not flood unicast traffic to ports that turn it off, nor
198 * other traffic if flood off, except for traffic we originate
199 */
200 switch (pkt_type) {
201 case BR_PKT_UNICAST:
202 if (!(p->flags & BR_FLOOD))
203 continue;
204 break;
205 case BR_PKT_MULTICAST:
206 if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
207 continue;
208 break;
209 case BR_PKT_BROADCAST:
210 if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
211 continue;
212 break;
213 }
214
215 /* Do not flood to ports that enable proxy ARP */
216 if (p->flags & BR_PROXYARP)
217 continue;
218 if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) &&
219 BR_INPUT_SKB_CB(skb)->proxyarp_replied)
220 continue;
221
222 prev = maybe_deliver(prev, p, skb, local_orig);
223 if (IS_ERR(prev))
224 goto out;
225 }
226
227 if (!prev)
228 goto out;
229
230 if (local_rcv)
231 deliver_clone(prev, skb, local_orig);
232 else
233 __br_forward(prev, skb, local_orig);
234 return;
235
236out:
237 if (!local_rcv)
238 kfree_skb(skb);
239}
240
241#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
242static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
243 const unsigned char *addr, bool local_orig)
244{
245 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
246 const unsigned char *src = eth_hdr(skb)->h_source;
247
248 if (!should_deliver(p, skb))
249 return;
250
251 /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
252 if (skb->dev == p->dev && ether_addr_equal(src, addr))
253 return;
254
255 skb = skb_copy(skb, GFP_ATOMIC);
256 if (!skb) {
257 dev->stats.tx_dropped++;
258 return;
259 }
260
261 if (!is_broadcast_ether_addr(addr))
262 memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
263
264 __br_forward(p, skb, local_orig);
265}
266
267/* called with rcu_read_lock */
268void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
269 struct sk_buff *skb,
270 bool local_rcv, bool local_orig)
271{
272 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
273 struct net_bridge *br = netdev_priv(dev);
274 struct net_bridge_port *prev = NULL;
275 struct net_bridge_port_group *p;
276 bool allow_mode_include = true;
277 struct hlist_node *rp;
278
279 rp = br_multicast_get_first_rport_node(br, skb);
280
281 if (mdst) {
282 p = rcu_dereference(mdst->ports);
283 if (br_multicast_should_handle_mode(br, mdst->addr.proto) &&
284 br_multicast_is_star_g(&mdst->addr))
285 allow_mode_include = false;
286 } else {
287 p = NULL;
288 }
289
290 while (p || rp) {
291 struct net_bridge_port *port, *lport, *rport;
292
293 lport = p ? p->key.port : NULL;
294 rport = br_multicast_rport_from_node_skb(rp, skb);
295
296 if ((unsigned long)lport > (unsigned long)rport) {
297 port = lport;
298
299 if (port->flags & BR_MULTICAST_TO_UNICAST) {
300 maybe_deliver_addr(lport, skb, p->eth_addr,
301 local_orig);
302 goto delivered;
303 }
304 if ((!allow_mode_include &&
305 p->filter_mode == MCAST_INCLUDE) ||
306 (p->flags & MDB_PG_FLAGS_BLOCKED))
307 goto delivered;
308 } else {
309 port = rport;
310 }
311
312 prev = maybe_deliver(prev, port, skb, local_orig);
313 if (IS_ERR(prev))
314 goto out;
315delivered:
316 if ((unsigned long)lport >= (unsigned long)port)
317 p = rcu_dereference(p->next);
318 if ((unsigned long)rport >= (unsigned long)port)
319 rp = rcu_dereference(hlist_next_rcu(rp));
320 }
321
322 if (!prev)
323 goto out;
324
325 if (local_rcv)
326 deliver_clone(prev, skb, local_orig);
327 else
328 __br_forward(prev, skb, local_orig);
329 return;
330
331out:
332 if (!local_rcv)
333 kfree_skb(skb);
334}
335#endif