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 */ |
21 | static 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(to: p, skb); |
31 | } |
32 | |
33 | int 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(dev: 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(ethertype: skb->protocol)) { |
43 | int depth; |
44 | |
45 | if (!vlan_get_protocol_and_depth(skb, type: skb->protocol, depth: &depth)) |
46 | goto drop; |
47 | |
48 | skb_set_network_header(skb, offset: depth); |
49 | } |
50 | |
51 | br_switchdev_frame_set_offload_fwd_mark(skb); |
52 | |
53 | dev_queue_xmit(skb); |
54 | |
55 | return 0; |
56 | |
57 | drop: |
58 | kfree_skb(skb); |
59 | return 0; |
60 | } |
61 | EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit); |
62 | |
63 | int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb) |
64 | { |
65 | skb_clear_tstamp(skb); |
66 | return NF_HOOK(pf: NFPROTO_BRIDGE, NF_BR_POST_ROUTING, |
67 | net, sk, skb, NULL, out: skb->dev, |
68 | okfn: br_dev_queue_push_xmit); |
69 | |
70 | } |
71 | EXPORT_SYMBOL_GPL(br_forward_finish); |
72 | |
73 | static 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(p: to, skb); |
85 | |
86 | vg = nbp_vlan_group_rcu(p: to); |
87 | skb = br_handle_vlan(br: to->br, port: 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(dev: indev); |
101 | } else { |
102 | if (unlikely(netpoll_tx_running(to->br->dev))) { |
103 | skb_push(skb, ETH_HLEN); |
104 | if (!is_skb_forwardable(dev: skb->dev, skb)) |
105 | kfree_skb(skb); |
106 | else |
107 | br_netpoll_send_skb(p: to, skb); |
108 | return; |
109 | } |
110 | br_hook = NF_BR_LOCAL_OUT; |
111 | net = dev_net(dev: skb->dev); |
112 | indev = NULL; |
113 | } |
114 | |
115 | NF_HOOK(pf: NFPROTO_BRIDGE, hook: br_hook, |
116 | net, NULL, skb, in: indev, out: skb->dev, |
117 | okfn: br_forward_finish); |
118 | } |
119 | |
120 | static 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(to: 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 | */ |
144 | void 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(dev: 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(p: to, skb)) { |
162 | if (local_rcv) |
163 | deliver_clone(prev: to, skb, local_orig); |
164 | else |
165 | __br_forward(to, skb, local_orig); |
166 | return; |
167 | } |
168 | |
169 | out: |
170 | if (!local_rcv) |
171 | kfree_skb(skb); |
172 | } |
173 | EXPORT_SYMBOL_GPL(br_forward); |
174 | |
175 | static 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(error: err); |
193 | out: |
194 | br_multicast_count(br: p->br, p, skb, type: igmp_type, dir: BR_MCAST_DIR_TX); |
195 | |
196 | return p; |
197 | } |
198 | |
199 | /* called under rcu_read_lock */ |
200 | void 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, miss: 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(ptr: 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(to: prev, skb, local_orig); |
248 | return; |
249 | |
250 | out: |
251 | if (!local_rcv) |
252 | kfree_skb(skb); |
253 | } |
254 | |
255 | #ifdef CONFIG_BRIDGE_IGMP_SNOOPING |
256 | static 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(addr1: src, addr2: 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(to: p, skb, local_orig); |
279 | } |
280 | |
281 | /* called with rcu_read_lock */ |
282 | void 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, proto: mdst->addr.proto) && |
297 | br_multicast_is_star_g(ip: &mdst->addr)) |
298 | allow_mode_include = false; |
299 | } else { |
300 | p = NULL; |
301 | br_tc_skb_miss_set(skb, miss: 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(p: lport, skb, addr: 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, p: port, skb, local_orig); |
327 | if (IS_ERR(ptr: prev)) |
328 | goto out; |
329 | delivered: |
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(to: prev, skb, local_orig); |
343 | return; |
344 | |
345 | out: |
346 | if (!local_rcv) |
347 | kfree_skb(skb); |
348 | } |
349 | #endif |
350 | |