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Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * Forwarding decision | |
4 | * Linux ethernet bridge | |
5 | * | |
6 | * Authors: | |
7 | * Lennert Buytenhek <buytenh@gnu.org> | |
1da177e4 LT |
8 | */ |
9 | ||
025d89c2 | 10 | #include <linux/err.h> |
5a0e3ad6 | 11 | #include <linux/slab.h> |
1da177e4 LT |
12 | #include <linux/kernel.h> |
13 | #include <linux/netdevice.h> | |
c06ee961 | 14 | #include <linux/netpoll.h> |
1da177e4 | 15 | #include <linux/skbuff.h> |
85ca719e | 16 | #include <linux/if_vlan.h> |
1da177e4 LT |
17 | #include <linux/netfilter_bridge.h> |
18 | #include "br_private.h" | |
19 | ||
1a81a2e0 | 20 | /* Don't forward packets to originating port or forwarding disabled */ |
9d6f229f | 21 | static inline int should_deliver(const struct net_bridge_port *p, |
1da177e4 LT |
22 | const struct sk_buff *skb) |
23 | { | |
2594e906 NA |
24 | struct net_bridge_vlan_group *vg; |
25 | ||
907b1e6e | 26 | vg = nbp_vlan_group_rcu(p); |
a97bfc1d | 27 | return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) && |
6bc506b4 | 28 | br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING && |
7d850abd NA |
29 | nbp_switchdev_allowed_egress(p, skb) && |
30 | !br_skb_isolated(p, skb); | |
1da177e4 LT |
31 | } |
32 | ||
0c4b51f0 | 33 | int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb) |
1da177e4 | 34 | { |
28c1382f | 35 | skb_push(skb, ETH_HLEN); |
df356d5e TM |
36 | if (!is_skb_forwardable(skb->dev, skb)) |
37 | goto drop; | |
38 | ||
df356d5e | 39 | br_drop_fake_rtable(skb); |
df356d5e TM |
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); | |
1da177e4 LT |
50 | } |
51 | ||
df356d5e TM |
52 | dev_queue_xmit(skb); |
53 | ||
54 | return 0; | |
55 | ||
56 | drop: | |
57 | kfree_skb(skb); | |
1da177e4 LT |
58 | return 0; |
59 | } | |
34666d46 | 60 | EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit); |
1da177e4 | 61 | |
0c4b51f0 | 62 | int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb) |
1da177e4 | 63 | { |
41d1c883 | 64 | skb->tstamp = 0; |
29a26a56 EB |
65 | return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, |
66 | net, sk, skb, NULL, skb->dev, | |
9ef513be | 67 | br_dev_queue_push_xmit); |
1da177e4 | 68 | |
1da177e4 | 69 | } |
34666d46 | 70 | EXPORT_SYMBOL_GPL(br_forward_finish); |
1da177e4 | 71 | |
37b090e6 NA |
72 | static void __br_forward(const struct net_bridge_port *to, |
73 | struct sk_buff *skb, bool local_orig) | |
1da177e4 | 74 | { |
2594e906 | 75 | struct net_bridge_vlan_group *vg; |
37b090e6 NA |
76 | struct net_device *indev; |
77 | struct net *net; | |
78 | int br_hook; | |
2594e906 | 79 | |
907b1e6e | 80 | vg = nbp_vlan_group_rcu(to); |
11538d03 | 81 | skb = br_handle_vlan(to->br, to, vg, skb); |
78851988 VY |
82 | if (!skb) |
83 | return; | |
84 | ||
37b090e6 | 85 | indev = skb->dev; |
1da177e4 | 86 | skb->dev = to->dev; |
37b090e6 NA |
87 | if (!local_orig) { |
88 | if (skb_warn_if_lro(skb)) { | |
91d2c34a | 89 | kfree_skb(skb); |
37b090e6 | 90 | return; |
91d2c34a | 91 | } |
37b090e6 NA |
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))) { | |
28c1382f YW |
97 | skb_push(skb, ETH_HLEN); |
98 | if (!is_skb_forwardable(skb->dev, skb)) | |
37b090e6 | 99 | kfree_skb(skb); |
28c1382f | 100 | else |
37b090e6 | 101 | br_netpoll_send_skb(to, skb); |
37b090e6 NA |
102 | return; |
103 | } | |
104 | br_hook = NF_BR_LOCAL_OUT; | |
105 | net = dev_net(skb->dev); | |
106 | indev = NULL; | |
91d2c34a HX |
107 | } |
108 | ||
37b090e6 NA |
109 | NF_HOOK(NFPROTO_BRIDGE, br_hook, |
110 | net, NULL, skb, indev, skb->dev, | |
713aefa3 | 111 | br_forward_finish); |
1da177e4 LT |
112 | } |
113 | ||
37b090e6 NA |
114 | static int deliver_clone(const struct net_bridge_port *prev, |
115 | struct sk_buff *skb, bool local_orig) | |
1da177e4 | 116 | { |
37b090e6 | 117 | struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev; |
1da177e4 | 118 | |
37b090e6 NA |
119 | skb = skb_clone(skb, GFP_ATOMIC); |
120 | if (!skb) { | |
121 | dev->stats.tx_dropped++; | |
122 | return -ENOMEM; | |
1da177e4 LT |
123 | } |
124 | ||
37b090e6 NA |
125 | __br_forward(prev, skb, local_orig); |
126 | return 0; | |
1da177e4 LT |
127 | } |
128 | ||
37b090e6 NA |
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 | */ | |
138 | void br_forward(const struct net_bridge_port *to, | |
139 | struct sk_buff *skb, bool local_rcv, bool local_orig) | |
1da177e4 | 140 | { |
2756f68c NA |
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)) { | |
b35c5f63 | 155 | if (local_rcv) |
37b090e6 | 156 | deliver_clone(to, skb, local_orig); |
7f7708f0 | 157 | else |
37b090e6 | 158 | __br_forward(to, skb, local_orig); |
1da177e4 LT |
159 | return; |
160 | } | |
161 | ||
2756f68c | 162 | out: |
b35c5f63 | 163 | if (!local_rcv) |
7f7708f0 | 164 | kfree_skb(skb); |
1da177e4 | 165 | } |
37b090e6 | 166 | EXPORT_SYMBOL_GPL(br_forward); |
025d89c2 HX |
167 | |
168 | static struct net_bridge_port *maybe_deliver( | |
169 | struct net_bridge_port *prev, struct net_bridge_port *p, | |
37b090e6 | 170 | struct sk_buff *skb, bool local_orig) |
025d89c2 | 171 | { |
847d44ef | 172 | u8 igmp_type = br_multicast_igmp_type(skb); |
025d89c2 HX |
173 | int err; |
174 | ||
175 | if (!should_deliver(p, skb)) | |
176 | return prev; | |
177 | ||
178 | if (!prev) | |
179 | goto out; | |
180 | ||
37b090e6 | 181 | err = deliver_clone(prev, skb, local_orig); |
025d89c2 HX |
182 | if (err) |
183 | return ERR_PTR(err); | |
025d89c2 | 184 | out: |
847d44ef PNA |
185 | br_multicast_count(p->br, p, skb, igmp_type, BR_MCAST_DIR_TX); |
186 | ||
025d89c2 HX |
187 | return p; |
188 | } | |
189 | ||
37b090e6 NA |
190 | /* called under rcu_read_lock */ |
191 | void br_flood(struct net_bridge *br, struct sk_buff *skb, | |
8addd5e7 | 192 | enum br_pkt_type pkt_type, bool local_rcv, bool local_orig) |
1da177e4 | 193 | { |
37b090e6 | 194 | struct net_bridge_port *prev = NULL; |
1080ab95 | 195 | struct net_bridge_port *p; |
1da177e4 | 196 | |
1da177e4 | 197 | list_for_each_entry_rcu(p, &br->port_list, list) { |
99f906e9 MM |
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 | } | |
95850116 KP |
215 | |
216 | /* Do not flood to ports that enable proxy ARP */ | |
217 | if (p->flags & BR_PROXYARP) | |
218 | continue; | |
821f1b21 | 219 | if ((p->flags & (BR_PROXYARP_WIFI | BR_NEIGH_SUPPRESS)) && |
842a9ae0 JM |
220 | BR_INPUT_SKB_CB(skb)->proxyarp_replied) |
221 | continue; | |
95850116 | 222 | |
37b090e6 | 223 | prev = maybe_deliver(prev, p, skb, local_orig); |
025d89c2 HX |
224 | if (IS_ERR(prev)) |
225 | goto out; | |
1da177e4 LT |
226 | } |
227 | ||
b33084be HX |
228 | if (!prev) |
229 | goto out; | |
230 | ||
b35c5f63 | 231 | if (local_rcv) |
37b090e6 | 232 | deliver_clone(prev, skb, local_orig); |
025d89c2 | 233 | else |
37b090e6 | 234 | __br_forward(prev, skb, local_orig); |
b33084be | 235 | return; |
1da177e4 | 236 | |
b33084be | 237 | out: |
b35c5f63 | 238 | if (!local_rcv) |
b33084be | 239 | kfree_skb(skb); |
1da177e4 LT |
240 | } |
241 | ||
5cb5e947 | 242 | #ifdef CONFIG_BRIDGE_IGMP_SNOOPING |
5b9d6b15 AB |
243 | static 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 | ||
5cb5e947 | 268 | /* called with rcu_read_lock */ |
37b090e6 NA |
269 | void br_multicast_flood(struct net_bridge_mdb_entry *mdst, |
270 | struct sk_buff *skb, | |
271 | bool local_rcv, bool local_orig) | |
5cb5e947 HX |
272 | { |
273 | struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev; | |
274 | struct net_bridge *br = netdev_priv(dev); | |
afe0159d | 275 | struct net_bridge_port *prev = NULL; |
5cb5e947 HX |
276 | struct net_bridge_port_group *p; |
277 | struct hlist_node *rp; | |
278 | ||
e8051688 | 279 | rp = rcu_dereference(hlist_first_rcu(&br->router_list)); |
83f6a740 | 280 | p = mdst ? rcu_dereference(mdst->ports) : NULL; |
5cb5e947 | 281 | while (p || rp) { |
afe0159d | 282 | struct net_bridge_port *port, *lport, *rport; |
283 | ||
5cb5e947 | 284 | lport = p ? p->port : NULL; |
d8fb1648 | 285 | rport = hlist_entry_safe(rp, struct net_bridge_port, rlist); |
5cb5e947 | 286 | |
6db6f0ea FF |
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 | } | |
5cb5e947 | 298 | |
37b090e6 | 299 | prev = maybe_deliver(prev, port, skb, local_orig); |
5cb5e947 HX |
300 | if (IS_ERR(prev)) |
301 | goto out; | |
847d44ef | 302 | delivered: |
5cb5e947 | 303 | if ((unsigned long)lport >= (unsigned long)port) |
83f6a740 | 304 | p = rcu_dereference(p->next); |
5cb5e947 | 305 | if ((unsigned long)rport >= (unsigned long)port) |
e8051688 | 306 | rp = rcu_dereference(hlist_next_rcu(rp)); |
5cb5e947 HX |
307 | } |
308 | ||
309 | if (!prev) | |
310 | goto out; | |
311 | ||
b35c5f63 | 312 | if (local_rcv) |
37b090e6 | 313 | deliver_clone(prev, skb, local_orig); |
5cb5e947 | 314 | else |
37b090e6 | 315 | __br_forward(prev, skb, local_orig); |
5cb5e947 HX |
316 | return; |
317 | ||
318 | out: | |
b35c5f63 | 319 | if (!local_rcv) |
5cb5e947 HX |
320 | kfree_skb(skb); |
321 | } | |
5cb5e947 | 322 | #endif |