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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 eth_type_vlan(skb->protocol)) {
43 int depth;
44
45 if (!vlan_get_protocol_and_depth(skb, skb->protocol, &depth))
46 goto drop;
47
48 skb_set_network_header(skb, depth);
49 }
50
51 br_switchdev_frame_set_offload_fwd_mark(skb);
52
53 dev_queue_xmit(skb);
54
55 return 0;
56
57drop:
58 kfree_skb(skb);
59 return 0;
60}
61EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
62
63int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
64{
65 skb_clear_tstamp(skb);
66 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
67 net, sk, skb, NULL, skb->dev,
68 br_dev_queue_push_xmit);
69
70}
71EXPORT_SYMBOL_GPL(br_forward_finish);
72
73static void __br_forward(const struct net_bridge_port *to,
74 struct sk_buff *skb, bool local_orig)
75{
76 struct net_bridge_vlan_group *vg;
77 struct net_device *indev;
78 struct net *net;
79 int br_hook;
80
81 /* Mark the skb for forwarding offload early so that br_handle_vlan()
82 * can know whether to pop the VLAN header on egress or keep it.
83 */
84 nbp_switchdev_frame_mark_tx_fwd_offload(to, skb);
85
86 vg = nbp_vlan_group_rcu(to);
87 skb = br_handle_vlan(to->br, to, vg, skb);
88 if (!skb)
89 return;
90
91 indev = skb->dev;
92 skb->dev = to->dev;
93 if (!local_orig) {
94 if (skb_warn_if_lro(skb)) {
95 kfree_skb(skb);
96 return;
97 }
98 br_hook = NF_BR_FORWARD;
99 skb_forward_csum(skb);
100 net = dev_net(indev);
101 } else {
102 if (unlikely(netpoll_tx_running(to->br->dev))) {
103 skb_push(skb, ETH_HLEN);
104 if (!is_skb_forwardable(skb->dev, skb))
105 kfree_skb(skb);
106 else
107 br_netpoll_send_skb(to, skb);
108 return;
109 }
110 br_hook = NF_BR_LOCAL_OUT;
111 net = dev_net(skb->dev);
112 indev = NULL;
113 }
114
115 NF_HOOK(NFPROTO_BRIDGE, br_hook,
116 net, NULL, skb, indev, skb->dev,
117 br_forward_finish);
118}
119
120static int deliver_clone(const struct net_bridge_port *prev,
121 struct sk_buff *skb, bool local_orig)
122{
123 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
124
125 skb = skb_clone(skb, GFP_ATOMIC);
126 if (!skb) {
127 DEV_STATS_INC(dev, tx_dropped);
128 return -ENOMEM;
129 }
130
131 __br_forward(prev, skb, local_orig);
132 return 0;
133}
134
135/**
136 * br_forward - forward a packet to a specific port
137 * @to: destination port
138 * @skb: packet being forwarded
139 * @local_rcv: packet will be received locally after forwarding
140 * @local_orig: packet is locally originated
141 *
142 * Should be called with rcu_read_lock.
143 */
144void br_forward(const struct net_bridge_port *to,
145 struct sk_buff *skb, bool local_rcv, bool local_orig)
146{
147 if (unlikely(!to))
148 goto out;
149
150 /* redirect to backup link if the destination port is down */
151 if (rcu_access_pointer(to->backup_port) && !netif_carrier_ok(to->dev)) {
152 struct net_bridge_port *backup_port;
153
154 backup_port = rcu_dereference(to->backup_port);
155 if (unlikely(!backup_port))
156 goto out;
157 BR_INPUT_SKB_CB(skb)->backup_nhid = READ_ONCE(to->backup_nhid);
158 to = backup_port;
159 }
160
161 if (should_deliver(to, skb)) {
162 if (local_rcv)
163 deliver_clone(to, skb, local_orig);
164 else
165 __br_forward(to, skb, local_orig);
166 return;
167 }
168
169out:
170 if (!local_rcv)
171 kfree_skb(skb);
172}
173EXPORT_SYMBOL_GPL(br_forward);
174
175static struct net_bridge_port *maybe_deliver(
176 struct net_bridge_port *prev, struct net_bridge_port *p,
177 struct sk_buff *skb, bool local_orig)
178{
179 u8 igmp_type = br_multicast_igmp_type(skb);
180 int err;
181
182 if (!should_deliver(p, skb))
183 return prev;
184
185 nbp_switchdev_frame_mark_tx_fwd_to_hwdom(p, skb);
186
187 if (!prev)
188 goto out;
189
190 err = deliver_clone(prev, skb, local_orig);
191 if (err)
192 return ERR_PTR(err);
193out:
194 br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX);
195
196 return p;
197}
198
199/* called under rcu_read_lock */
200void br_flood(struct net_bridge *br, struct sk_buff *skb,
201 enum br_pkt_type pkt_type, bool local_rcv, bool local_orig,
202 u16 vid)
203{
204 struct net_bridge_port *prev = NULL;
205 struct net_bridge_port *p;
206
207 br_tc_skb_miss_set(skb, pkt_type != BR_PKT_BROADCAST);
208
209 list_for_each_entry_rcu(p, &br->port_list, list) {
210 /* Do not flood unicast traffic to ports that turn it off, nor
211 * other traffic if flood off, except for traffic we originate
212 */
213 switch (pkt_type) {
214 case BR_PKT_UNICAST:
215 if (!(p->flags & BR_FLOOD))
216 continue;
217 break;
218 case BR_PKT_MULTICAST:
219 if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
220 continue;
221 break;
222 case BR_PKT_BROADCAST:
223 if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
224 continue;
225 break;
226 }
227
228 /* Do not flood to ports that enable proxy ARP */
229 if (p->flags & BR_PROXYARP)
230 continue;
231 if (BR_INPUT_SKB_CB(skb)->proxyarp_replied &&
232 ((p->flags & BR_PROXYARP_WIFI) ||
233 br_is_neigh_suppress_enabled(p, vid)))
234 continue;
235
236 prev = maybe_deliver(prev, p, skb, local_orig);
237 if (IS_ERR(prev))
238 goto out;
239 }
240
241 if (!prev)
242 goto out;
243
244 if (local_rcv)
245 deliver_clone(prev, skb, local_orig);
246 else
247 __br_forward(prev, skb, local_orig);
248 return;
249
250out:
251 if (!local_rcv)
252 kfree_skb(skb);
253}
254
255#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
256static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
257 const unsigned char *addr, bool local_orig)
258{
259 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
260 const unsigned char *src = eth_hdr(skb)->h_source;
261
262 if (!should_deliver(p, skb))
263 return;
264
265 /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
266 if (skb->dev == p->dev && ether_addr_equal(src, addr))
267 return;
268
269 skb = skb_copy(skb, GFP_ATOMIC);
270 if (!skb) {
271 DEV_STATS_INC(dev, tx_dropped);
272 return;
273 }
274
275 if (!is_broadcast_ether_addr(addr))
276 memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
277
278 __br_forward(p, skb, local_orig);
279}
280
281/* called with rcu_read_lock */
282void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
283 struct sk_buff *skb,
284 struct net_bridge_mcast *brmctx,
285 bool local_rcv, bool local_orig)
286{
287 struct net_bridge_port *prev = NULL;
288 struct net_bridge_port_group *p;
289 bool allow_mode_include = true;
290 struct hlist_node *rp;
291
292 rp = br_multicast_get_first_rport_node(brmctx, skb);
293
294 if (mdst) {
295 p = rcu_dereference(mdst->ports);
296 if (br_multicast_should_handle_mode(brmctx, mdst->addr.proto) &&
297 br_multicast_is_star_g(&mdst->addr))
298 allow_mode_include = false;
299 } else {
300 p = NULL;
301 br_tc_skb_miss_set(skb, true);
302 }
303
304 while (p || rp) {
305 struct net_bridge_port *port, *lport, *rport;
306
307 lport = p ? p->key.port : NULL;
308 rport = br_multicast_rport_from_node_skb(rp, skb);
309
310 if ((unsigned long)lport > (unsigned long)rport) {
311 port = lport;
312
313 if (port->flags & BR_MULTICAST_TO_UNICAST) {
314 maybe_deliver_addr(lport, skb, p->eth_addr,
315 local_orig);
316 goto delivered;
317 }
318 if ((!allow_mode_include &&
319 p->filter_mode == MCAST_INCLUDE) ||
320 (p->flags & MDB_PG_FLAGS_BLOCKED))
321 goto delivered;
322 } else {
323 port = rport;
324 }
325
326 prev = maybe_deliver(prev, port, skb, local_orig);
327 if (IS_ERR(prev))
328 goto out;
329delivered:
330 if ((unsigned long)lport >= (unsigned long)port)
331 p = rcu_dereference(p->next);
332 if ((unsigned long)rport >= (unsigned long)port)
333 rp = rcu_dereference(hlist_next_rcu(rp));
334 }
335
336 if (!prev)
337 goto out;
338
339 if (local_rcv)
340 deliver_clone(prev, skb, local_orig);
341 else
342 __br_forward(prev, skb, local_orig);
343 return;
344
345out:
346 if (!local_rcv)
347 kfree_skb(skb);
348}
349#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 br_switchdev_frame_set_offload_fwd_mark(skb);
52
53 dev_queue_xmit(skb);
54
55 return 0;
56
57drop:
58 kfree_skb(skb);
59 return 0;
60}
61EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
62
63int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
64{
65 skb_clear_tstamp(skb);
66 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
67 net, sk, skb, NULL, skb->dev,
68 br_dev_queue_push_xmit);
69
70}
71EXPORT_SYMBOL_GPL(br_forward_finish);
72
73static void __br_forward(const struct net_bridge_port *to,
74 struct sk_buff *skb, bool local_orig)
75{
76 struct net_bridge_vlan_group *vg;
77 struct net_device *indev;
78 struct net *net;
79 int br_hook;
80
81 /* Mark the skb for forwarding offload early so that br_handle_vlan()
82 * can know whether to pop the VLAN header on egress or keep it.
83 */
84 nbp_switchdev_frame_mark_tx_fwd_offload(to, skb);
85
86 vg = nbp_vlan_group_rcu(to);
87 skb = br_handle_vlan(to->br, to, vg, skb);
88 if (!skb)
89 return;
90
91 indev = skb->dev;
92 skb->dev = to->dev;
93 if (!local_orig) {
94 if (skb_warn_if_lro(skb)) {
95 kfree_skb(skb);
96 return;
97 }
98 br_hook = NF_BR_FORWARD;
99 skb_forward_csum(skb);
100 net = dev_net(indev);
101 } else {
102 if (unlikely(netpoll_tx_running(to->br->dev))) {
103 skb_push(skb, ETH_HLEN);
104 if (!is_skb_forwardable(skb->dev, skb))
105 kfree_skb(skb);
106 else
107 br_netpoll_send_skb(to, skb);
108 return;
109 }
110 br_hook = NF_BR_LOCAL_OUT;
111 net = dev_net(skb->dev);
112 indev = NULL;
113 }
114
115 NF_HOOK(NFPROTO_BRIDGE, br_hook,
116 net, NULL, skb, indev, skb->dev,
117 br_forward_finish);
118}
119
120static int deliver_clone(const struct net_bridge_port *prev,
121 struct sk_buff *skb, bool local_orig)
122{
123 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
124
125 skb = skb_clone(skb, GFP_ATOMIC);
126 if (!skb) {
127 dev->stats.tx_dropped++;
128 return -ENOMEM;
129 }
130
131 __br_forward(prev, skb, local_orig);
132 return 0;
133}
134
135/**
136 * br_forward - forward a packet to a specific port
137 * @to: destination port
138 * @skb: packet being forwarded
139 * @local_rcv: packet will be received locally after forwarding
140 * @local_orig: packet is locally originated
141 *
142 * Should be called with rcu_read_lock.
143 */
144void br_forward(const struct net_bridge_port *to,
145 struct sk_buff *skb, bool local_rcv, bool local_orig)
146{
147 if (unlikely(!to))
148 goto out;
149
150 /* redirect to backup link if the destination port is down */
151 if (rcu_access_pointer(to->backup_port) && !netif_carrier_ok(to->dev)) {
152 struct net_bridge_port *backup_port;
153
154 backup_port = rcu_dereference(to->backup_port);
155 if (unlikely(!backup_port))
156 goto out;
157 to = backup_port;
158 }
159
160 if (should_deliver(to, skb)) {
161 if (local_rcv)
162 deliver_clone(to, skb, local_orig);
163 else
164 __br_forward(to, skb, local_orig);
165 return;
166 }
167
168out:
169 if (!local_rcv)
170 kfree_skb(skb);
171}
172EXPORT_SYMBOL_GPL(br_forward);
173
174static struct net_bridge_port *maybe_deliver(
175 struct net_bridge_port *prev, struct net_bridge_port *p,
176 struct sk_buff *skb, bool local_orig)
177{
178 u8 igmp_type = br_multicast_igmp_type(skb);
179 int err;
180
181 if (!should_deliver(p, skb))
182 return prev;
183
184 nbp_switchdev_frame_mark_tx_fwd_to_hwdom(p, skb);
185
186 if (!prev)
187 goto out;
188
189 err = deliver_clone(prev, skb, local_orig);
190 if (err)
191 return ERR_PTR(err);
192out:
193 br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX);
194
195 return p;
196}
197
198/* called under rcu_read_lock */
199void br_flood(struct net_bridge *br, struct sk_buff *skb,
200 enum br_pkt_type pkt_type, bool local_rcv, bool local_orig)
201{
202 struct net_bridge_port *prev = NULL;
203 struct net_bridge_port *p;
204
205 list_for_each_entry_rcu(p, &br->port_list, list) {
206 /* Do not flood unicast traffic to ports that turn it off, nor
207 * other traffic if flood off, except for traffic we originate
208 */
209 switch (pkt_type) {
210 case BR_PKT_UNICAST:
211 if (!(p->flags & BR_FLOOD))
212 continue;
213 break;
214 case BR_PKT_MULTICAST:
215 if (!(p->flags & BR_MCAST_FLOOD) && skb->dev != br->dev)
216 continue;
217 break;
218 case BR_PKT_BROADCAST:
219 if (!(p->flags & BR_BCAST_FLOOD) && skb->dev != br->dev)
220 continue;
221 break;
222 }
223
224 /* Do not flood to ports that enable proxy ARP */
225 if (p->flags & BR_PROXYARP)
226 continue;
227 if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) &&
228 BR_INPUT_SKB_CB(skb)->proxyarp_replied)
229 continue;
230
231 prev = maybe_deliver(prev, p, skb, local_orig);
232 if (IS_ERR(prev))
233 goto out;
234 }
235
236 if (!prev)
237 goto out;
238
239 if (local_rcv)
240 deliver_clone(prev, skb, local_orig);
241 else
242 __br_forward(prev, skb, local_orig);
243 return;
244
245out:
246 if (!local_rcv)
247 kfree_skb(skb);
248}
249
250#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
251static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
252 const unsigned char *addr, bool local_orig)
253{
254 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
255 const unsigned char *src = eth_hdr(skb)->h_source;
256
257 if (!should_deliver(p, skb))
258 return;
259
260 /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
261 if (skb->dev == p->dev && ether_addr_equal(src, addr))
262 return;
263
264 skb = skb_copy(skb, GFP_ATOMIC);
265 if (!skb) {
266 dev->stats.tx_dropped++;
267 return;
268 }
269
270 if (!is_broadcast_ether_addr(addr))
271 memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
272
273 __br_forward(p, skb, local_orig);
274}
275
276/* called with rcu_read_lock */
277void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
278 struct sk_buff *skb,
279 struct net_bridge_mcast *brmctx,
280 bool local_rcv, bool local_orig)
281{
282 struct net_bridge_port *prev = NULL;
283 struct net_bridge_port_group *p;
284 bool allow_mode_include = true;
285 struct hlist_node *rp;
286
287 rp = br_multicast_get_first_rport_node(brmctx, skb);
288
289 if (mdst) {
290 p = rcu_dereference(mdst->ports);
291 if (br_multicast_should_handle_mode(brmctx, mdst->addr.proto) &&
292 br_multicast_is_star_g(&mdst->addr))
293 allow_mode_include = false;
294 } else {
295 p = NULL;
296 }
297
298 while (p || rp) {
299 struct net_bridge_port *port, *lport, *rport;
300
301 lport = p ? p->key.port : NULL;
302 rport = br_multicast_rport_from_node_skb(rp, skb);
303
304 if ((unsigned long)lport > (unsigned long)rport) {
305 port = lport;
306
307 if (port->flags & BR_MULTICAST_TO_UNICAST) {
308 maybe_deliver_addr(lport, skb, p->eth_addr,
309 local_orig);
310 goto delivered;
311 }
312 if ((!allow_mode_include &&
313 p->filter_mode == MCAST_INCLUDE) ||
314 (p->flags & MDB_PG_FLAGS_BLOCKED))
315 goto delivered;
316 } else {
317 port = rport;
318 }
319
320 prev = maybe_deliver(prev, port, skb, local_orig);
321 if (IS_ERR(prev))
322 goto out;
323delivered:
324 if ((unsigned long)lport >= (unsigned long)port)
325 p = rcu_dereference(p->next);
326 if ((unsigned long)rport >= (unsigned long)port)
327 rp = rcu_dereference(hlist_next_rcu(rp));
328 }
329
330 if (!prev)
331 goto out;
332
333 if (local_rcv)
334 deliver_clone(prev, skb, local_orig);
335 else
336 __br_forward(prev, skb, local_orig);
337 return;
338
339out:
340 if (!local_rcv)
341 kfree_skb(skb);
342}
343#endif