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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 (br_mst_is_enabled(p->br) || p->state == BR_STATE_FORWARDING) &&
29 br_allowed_egress(vg, skb) && 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 struct sk_buff *nskb;
262
263 if (!should_deliver(p, skb))
264 return;
265
266 /* Even with hairpin, no soliloquies - prevent breaking IPv6 DAD */
267 if (skb->dev == p->dev && ether_addr_equal(src, addr))
268 return;
269
270 __skb_push(skb, ETH_HLEN);
271 nskb = pskb_copy(skb, GFP_ATOMIC);
272 __skb_pull(skb, ETH_HLEN);
273 if (!nskb) {
274 DEV_STATS_INC(dev, tx_dropped);
275 return;
276 }
277
278 skb = nskb;
279 __skb_pull(skb, ETH_HLEN);
280 if (!is_broadcast_ether_addr(addr))
281 memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
282
283 __br_forward(p, skb, local_orig);
284}
285
286/* called with rcu_read_lock */
287void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
288 struct sk_buff *skb,
289 struct net_bridge_mcast *brmctx,
290 bool local_rcv, bool local_orig)
291{
292 struct net_bridge_port *prev = NULL;
293 struct net_bridge_port_group *p;
294 bool allow_mode_include = true;
295 struct hlist_node *rp;
296
297 rp = br_multicast_get_first_rport_node(brmctx, skb);
298
299 if (mdst) {
300 p = rcu_dereference(mdst->ports);
301 if (br_multicast_should_handle_mode(brmctx, mdst->addr.proto) &&
302 br_multicast_is_star_g(&mdst->addr))
303 allow_mode_include = false;
304 } else {
305 p = NULL;
306 br_tc_skb_miss_set(skb, true);
307 }
308
309 while (p || rp) {
310 struct net_bridge_port *port, *lport, *rport;
311
312 lport = p ? p->key.port : NULL;
313 rport = br_multicast_rport_from_node_skb(rp, skb);
314
315 if ((unsigned long)lport > (unsigned long)rport) {
316 port = lport;
317
318 if (port->flags & BR_MULTICAST_TO_UNICAST) {
319 maybe_deliver_addr(lport, skb, p->eth_addr,
320 local_orig);
321 goto delivered;
322 }
323 if ((!allow_mode_include &&
324 p->filter_mode == MCAST_INCLUDE) ||
325 (p->flags & MDB_PG_FLAGS_BLOCKED))
326 goto delivered;
327 } else {
328 port = rport;
329 }
330
331 prev = maybe_deliver(prev, port, skb, local_orig);
332 if (IS_ERR(prev))
333 goto out;
334delivered:
335 if ((unsigned long)lport >= (unsigned long)port)
336 p = rcu_dereference(p->next);
337 if ((unsigned long)rport >= (unsigned long)port)
338 rp = rcu_dereference(hlist_next_rcu(rp));
339 }
340
341 if (!prev)
342 goto out;
343
344 if (local_rcv)
345 deliver_clone(prev, skb, local_orig);
346 else
347 __br_forward(prev, skb, local_orig);
348 return;
349
350out:
351 if (!local_rcv)
352 kfree_skb(skb);
353}
354#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