Merge tag 'gvt-fixes-2021-07-15' of https://github.com/intel/gvt-linux into drm-intel...
[platform/kernel/linux-rpi.git] / net / bridge / br_forward.c
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(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(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
55 drop:
56         kfree_skb(skb);
57         return 0;
58 }
59 EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
60
61 int 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 }
69 EXPORT_SYMBOL_GPL(br_forward_finish);
70
71 static 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
113 static 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  */
137 void 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
161 out:
162         if (!local_rcv)
163                 kfree_skb(skb);
164 }
165 EXPORT_SYMBOL_GPL(br_forward);
166
167 static 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);
183 out:
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 */
190 void 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
236 out:
237         if (!local_rcv)
238                 kfree_skb(skb);
239 }
240
241 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
242 static 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 */
268 void 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;
315 delivered:
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
331 out:
332         if (!local_rcv)
333                 kfree_skb(skb);
334 }
335 #endif