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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Handle incoming frames
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9
10#include <linux/slab.h>
11#include <linux/kernel.h>
12#include <linux/netdevice.h>
13#include <linux/etherdevice.h>
14#include <linux/netfilter_bridge.h>
15#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
16#include <net/netfilter/nf_queue.h>
17#endif
18#include <linux/neighbour.h>
19#include <net/arp.h>
20#include <linux/export.h>
21#include <linux/rculist.h>
22#include "br_private.h"
23#include "br_private_tunnel.h"
24
25static int
26br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
27{
28 br_drop_fake_rtable(skb);
29 return netif_receive_skb(skb);
30}
31
32static int br_pass_frame_up(struct sk_buff *skb)
33{
34 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
35 struct net_bridge *br = netdev_priv(brdev);
36 struct net_bridge_vlan_group *vg;
37 struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
38
39 u64_stats_update_begin(&brstats->syncp);
40 brstats->rx_packets++;
41 brstats->rx_bytes += skb->len;
42 u64_stats_update_end(&brstats->syncp);
43
44 vg = br_vlan_group_rcu(br);
45 /* Bridge is just like any other port. Make sure the
46 * packet is allowed except in promisc modue when someone
47 * may be running packet capture.
48 */
49 if (!(brdev->flags & IFF_PROMISC) &&
50 !br_allowed_egress(vg, skb)) {
51 kfree_skb(skb);
52 return NET_RX_DROP;
53 }
54
55 indev = skb->dev;
56 skb->dev = brdev;
57 skb = br_handle_vlan(br, NULL, vg, skb);
58 if (!skb)
59 return NET_RX_DROP;
60 /* update the multicast stats if the packet is IGMP/MLD */
61 br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb),
62 BR_MCAST_DIR_TX);
63
64 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
65 dev_net(indev), NULL, skb, indev, NULL,
66 br_netif_receive_skb);
67}
68
69/* note: already called with rcu_read_lock */
70int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
71{
72 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
73 enum br_pkt_type pkt_type = BR_PKT_UNICAST;
74 struct net_bridge_fdb_entry *dst = NULL;
75 struct net_bridge_mdb_entry *mdst;
76 bool local_rcv, mcast_hit = false;
77 struct net_bridge *br;
78 u16 vid = 0;
79
80 if (!p || p->state == BR_STATE_DISABLED)
81 goto drop;
82
83 if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid))
84 goto out;
85
86 nbp_switchdev_frame_mark(p, skb);
87
88 /* insert into forwarding database after filtering to avoid spoofing */
89 br = p->br;
90 if (p->flags & BR_LEARNING)
91 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
92
93 local_rcv = !!(br->dev->flags & IFF_PROMISC);
94 if (is_multicast_ether_addr(eth_hdr(skb)->h_dest)) {
95 /* by definition the broadcast is also a multicast address */
96 if (is_broadcast_ether_addr(eth_hdr(skb)->h_dest)) {
97 pkt_type = BR_PKT_BROADCAST;
98 local_rcv = true;
99 } else {
100 pkt_type = BR_PKT_MULTICAST;
101 if (br_multicast_rcv(br, p, skb, vid))
102 goto drop;
103 }
104 }
105
106 if (p->state == BR_STATE_LEARNING)
107 goto drop;
108
109 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
110 BR_INPUT_SKB_CB(skb)->src_port_isolated = !!(p->flags & BR_ISOLATED);
111
112 if (IS_ENABLED(CONFIG_INET) &&
113 (skb->protocol == htons(ETH_P_ARP) ||
114 skb->protocol == htons(ETH_P_RARP))) {
115 br_do_proxy_suppress_arp(skb, br, vid, p);
116 } else if (IS_ENABLED(CONFIG_IPV6) &&
117 skb->protocol == htons(ETH_P_IPV6) &&
118 br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
119 pskb_may_pull(skb, sizeof(struct ipv6hdr) +
120 sizeof(struct nd_msg)) &&
121 ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
122 struct nd_msg *msg, _msg;
123
124 msg = br_is_nd_neigh_msg(skb, &_msg);
125 if (msg)
126 br_do_suppress_nd(skb, br, vid, p, msg);
127 }
128
129 switch (pkt_type) {
130 case BR_PKT_MULTICAST:
131 mdst = br_mdb_get(br, skb, vid);
132 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
133 br_multicast_querier_exists(br, eth_hdr(skb))) {
134 if ((mdst && mdst->host_joined) ||
135 br_multicast_is_router(br)) {
136 local_rcv = true;
137 br->dev->stats.multicast++;
138 }
139 mcast_hit = true;
140 } else {
141 local_rcv = true;
142 br->dev->stats.multicast++;
143 }
144 break;
145 case BR_PKT_UNICAST:
146 dst = br_fdb_find_rcu(br, eth_hdr(skb)->h_dest, vid);
147 default:
148 break;
149 }
150
151 if (dst) {
152 unsigned long now = jiffies;
153
154 if (dst->is_local)
155 return br_pass_frame_up(skb);
156
157 if (now != dst->used)
158 dst->used = now;
159 br_forward(dst->dst, skb, local_rcv, false);
160 } else {
161 if (!mcast_hit)
162 br_flood(br, skb, pkt_type, local_rcv, false);
163 else
164 br_multicast_flood(mdst, skb, local_rcv, false);
165 }
166
167 if (local_rcv)
168 return br_pass_frame_up(skb);
169
170out:
171 return 0;
172drop:
173 kfree_skb(skb);
174 goto out;
175}
176EXPORT_SYMBOL_GPL(br_handle_frame_finish);
177
178static void __br_handle_local_finish(struct sk_buff *skb)
179{
180 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
181 u16 vid = 0;
182
183 /* check if vlan is allowed, to avoid spoofing */
184 if ((p->flags & BR_LEARNING) &&
185 !br_opt_get(p->br, BROPT_NO_LL_LEARN) &&
186 br_should_learn(p, skb, &vid))
187 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
188}
189
190/* note: already called with rcu_read_lock */
191static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
192{
193 __br_handle_local_finish(skb);
194
195 /* return 1 to signal the okfn() was called so it's ok to use the skb */
196 return 1;
197}
198
199static int nf_hook_bridge_pre(struct sk_buff *skb, struct sk_buff **pskb)
200{
201#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
202 struct nf_hook_entries *e = NULL;
203 struct nf_hook_state state;
204 unsigned int verdict, i;
205 struct net *net;
206 int ret;
207
208 net = dev_net(skb->dev);
209#ifdef HAVE_JUMP_LABEL
210 if (!static_key_false(&nf_hooks_needed[NFPROTO_BRIDGE][NF_BR_PRE_ROUTING]))
211 goto frame_finish;
212#endif
213
214 e = rcu_dereference(net->nf.hooks_bridge[NF_BR_PRE_ROUTING]);
215 if (!e)
216 goto frame_finish;
217
218 nf_hook_state_init(&state, NF_BR_PRE_ROUTING,
219 NFPROTO_BRIDGE, skb->dev, NULL, NULL,
220 net, br_handle_frame_finish);
221
222 for (i = 0; i < e->num_hook_entries; i++) {
223 verdict = nf_hook_entry_hookfn(&e->hooks[i], skb, &state);
224 switch (verdict & NF_VERDICT_MASK) {
225 case NF_ACCEPT:
226 if (BR_INPUT_SKB_CB(skb)->br_netfilter_broute) {
227 *pskb = skb;
228 return RX_HANDLER_PASS;
229 }
230 break;
231 case NF_DROP:
232 kfree_skb(skb);
233 return RX_HANDLER_CONSUMED;
234 case NF_QUEUE:
235 ret = nf_queue(skb, &state, i, verdict);
236 if (ret == 1)
237 continue;
238 return RX_HANDLER_CONSUMED;
239 default: /* STOLEN */
240 return RX_HANDLER_CONSUMED;
241 }
242 }
243frame_finish:
244 net = dev_net(skb->dev);
245 br_handle_frame_finish(net, NULL, skb);
246#else
247 br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
248#endif
249 return RX_HANDLER_CONSUMED;
250}
251
252/*
253 * Return NULL if skb is handled
254 * note: already called with rcu_read_lock
255 */
256rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
257{
258 struct net_bridge_port *p;
259 struct sk_buff *skb = *pskb;
260 const unsigned char *dest = eth_hdr(skb)->h_dest;
261
262 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
263 return RX_HANDLER_PASS;
264
265 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
266 goto drop;
267
268 skb = skb_share_check(skb, GFP_ATOMIC);
269 if (!skb)
270 return RX_HANDLER_CONSUMED;
271
272 memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
273
274 p = br_port_get_rcu(skb->dev);
275 if (p->flags & BR_VLAN_TUNNEL) {
276 if (br_handle_ingress_vlan_tunnel(skb, p,
277 nbp_vlan_group_rcu(p)))
278 goto drop;
279 }
280
281 if (unlikely(is_link_local_ether_addr(dest))) {
282 u16 fwd_mask = p->br->group_fwd_mask_required;
283
284 /*
285 * See IEEE 802.1D Table 7-10 Reserved addresses
286 *
287 * Assignment Value
288 * Bridge Group Address 01-80-C2-00-00-00
289 * (MAC Control) 802.3 01-80-C2-00-00-01
290 * (Link Aggregation) 802.3 01-80-C2-00-00-02
291 * 802.1X PAE address 01-80-C2-00-00-03
292 *
293 * 802.1AB LLDP 01-80-C2-00-00-0E
294 *
295 * Others reserved for future standardization
296 */
297 fwd_mask |= p->group_fwd_mask;
298 switch (dest[5]) {
299 case 0x00: /* Bridge Group Address */
300 /* If STP is turned off,
301 then must forward to keep loop detection */
302 if (p->br->stp_enabled == BR_NO_STP ||
303 fwd_mask & (1u << dest[5]))
304 goto forward;
305 *pskb = skb;
306 __br_handle_local_finish(skb);
307 return RX_HANDLER_PASS;
308
309 case 0x01: /* IEEE MAC (Pause) */
310 goto drop;
311
312 case 0x0E: /* 802.1AB LLDP */
313 fwd_mask |= p->br->group_fwd_mask;
314 if (fwd_mask & (1u << dest[5]))
315 goto forward;
316 *pskb = skb;
317 __br_handle_local_finish(skb);
318 return RX_HANDLER_PASS;
319
320 default:
321 /* Allow selective forwarding for most other protocols */
322 fwd_mask |= p->br->group_fwd_mask;
323 if (fwd_mask & (1u << dest[5]))
324 goto forward;
325 }
326
327 /* The else clause should be hit when nf_hook():
328 * - returns < 0 (drop/error)
329 * - returns = 0 (stolen/nf_queue)
330 * Thus return 1 from the okfn() to signal the skb is ok to pass
331 */
332 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
333 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
334 br_handle_local_finish) == 1) {
335 return RX_HANDLER_PASS;
336 } else {
337 return RX_HANDLER_CONSUMED;
338 }
339 }
340
341forward:
342 switch (p->state) {
343 case BR_STATE_FORWARDING:
344 case BR_STATE_LEARNING:
345 if (ether_addr_equal(p->br->dev->dev_addr, dest))
346 skb->pkt_type = PACKET_HOST;
347
348 return nf_hook_bridge_pre(skb, pskb);
349 default:
350drop:
351 kfree_skb(skb);
352 }
353 return RX_HANDLER_CONSUMED;
354}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Handle incoming frames
4 * Linux ethernet bridge
5 *
6 * Authors:
7 * Lennert Buytenhek <buytenh@gnu.org>
8 */
9
10#include <linux/slab.h>
11#include <linux/kernel.h>
12#include <linux/netdevice.h>
13#include <linux/etherdevice.h>
14#include <linux/netfilter_bridge.h>
15#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
16#include <net/netfilter/nf_queue.h>
17#endif
18#include <linux/neighbour.h>
19#include <net/arp.h>
20#include <net/dsa.h>
21#include <linux/export.h>
22#include <linux/rculist.h>
23#include "br_private.h"
24#include "br_private_tunnel.h"
25
26static int
27br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
28{
29 br_drop_fake_rtable(skb);
30 return netif_receive_skb(skb);
31}
32
33static int br_pass_frame_up(struct sk_buff *skb)
34{
35 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
36 struct net_bridge *br = netdev_priv(brdev);
37 struct net_bridge_vlan_group *vg;
38
39 dev_sw_netstats_rx_add(brdev, skb->len);
40
41 vg = br_vlan_group_rcu(br);
42
43 /* Reset the offload_fwd_mark because there could be a stacked
44 * bridge above, and it should not think this bridge it doing
45 * that bridge's work forwarding out its ports.
46 */
47 br_switchdev_frame_unmark(skb);
48
49 /* Bridge is just like any other port. Make sure the
50 * packet is allowed except in promisc mode when someone
51 * may be running packet capture.
52 */
53 if (!(brdev->flags & IFF_PROMISC) &&
54 !br_allowed_egress(vg, skb)) {
55 kfree_skb(skb);
56 return NET_RX_DROP;
57 }
58
59 indev = skb->dev;
60 skb->dev = brdev;
61 skb = br_handle_vlan(br, NULL, vg, skb);
62 if (!skb)
63 return NET_RX_DROP;
64 /* update the multicast stats if the packet is IGMP/MLD */
65 br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb),
66 BR_MCAST_DIR_TX);
67
68 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
69 dev_net(indev), NULL, skb, indev, NULL,
70 br_netif_receive_skb);
71}
72
73/* note: already called with rcu_read_lock */
74int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
75{
76 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
77 enum br_pkt_type pkt_type = BR_PKT_UNICAST;
78 struct net_bridge_fdb_entry *dst = NULL;
79 struct net_bridge_mcast_port *pmctx;
80 struct net_bridge_mdb_entry *mdst;
81 bool local_rcv, mcast_hit = false;
82 struct net_bridge_mcast *brmctx;
83 struct net_bridge_vlan *vlan;
84 struct net_bridge *br;
85 u16 vid = 0;
86 u8 state;
87
88 if (!p)
89 goto drop;
90
91 br = p->br;
92
93 if (br_mst_is_enabled(br)) {
94 state = BR_STATE_FORWARDING;
95 } else {
96 if (p->state == BR_STATE_DISABLED)
97 goto drop;
98
99 state = p->state;
100 }
101
102 brmctx = &p->br->multicast_ctx;
103 pmctx = &p->multicast_ctx;
104 if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid,
105 &state, &vlan))
106 goto out;
107
108 if (p->flags & BR_PORT_LOCKED) {
109 struct net_bridge_fdb_entry *fdb_src =
110 br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
111
112 if (!fdb_src) {
113 /* FDB miss. Create locked FDB entry if MAB is enabled
114 * and drop the packet.
115 */
116 if (p->flags & BR_PORT_MAB)
117 br_fdb_update(br, p, eth_hdr(skb)->h_source,
118 vid, BIT(BR_FDB_LOCKED));
119 goto drop;
120 } else if (READ_ONCE(fdb_src->dst) != p ||
121 test_bit(BR_FDB_LOCAL, &fdb_src->flags)) {
122 /* FDB mismatch. Drop the packet without roaming. */
123 goto drop;
124 } else if (test_bit(BR_FDB_LOCKED, &fdb_src->flags)) {
125 /* FDB match, but entry is locked. Refresh it and drop
126 * the packet.
127 */
128 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid,
129 BIT(BR_FDB_LOCKED));
130 goto drop;
131 }
132 }
133
134 nbp_switchdev_frame_mark(p, skb);
135
136 /* insert into forwarding database after filtering to avoid spoofing */
137 if (p->flags & BR_LEARNING)
138 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
139
140 local_rcv = !!(br->dev->flags & IFF_PROMISC);
141 if (is_multicast_ether_addr(eth_hdr(skb)->h_dest)) {
142 /* by definition the broadcast is also a multicast address */
143 if (is_broadcast_ether_addr(eth_hdr(skb)->h_dest)) {
144 pkt_type = BR_PKT_BROADCAST;
145 local_rcv = true;
146 } else {
147 pkt_type = BR_PKT_MULTICAST;
148 if (br_multicast_rcv(&brmctx, &pmctx, vlan, skb, vid))
149 goto drop;
150 }
151 }
152
153 if (state == BR_STATE_LEARNING)
154 goto drop;
155
156 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
157 BR_INPUT_SKB_CB(skb)->src_port_isolated = !!(p->flags & BR_ISOLATED);
158
159 if (IS_ENABLED(CONFIG_INET) &&
160 (skb->protocol == htons(ETH_P_ARP) ||
161 skb->protocol == htons(ETH_P_RARP))) {
162 br_do_proxy_suppress_arp(skb, br, vid, p);
163 } else if (IS_ENABLED(CONFIG_IPV6) &&
164 skb->protocol == htons(ETH_P_IPV6) &&
165 br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
166 pskb_may_pull(skb, sizeof(struct ipv6hdr) +
167 sizeof(struct nd_msg)) &&
168 ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
169 struct nd_msg *msg, _msg;
170
171 msg = br_is_nd_neigh_msg(skb, &_msg);
172 if (msg)
173 br_do_suppress_nd(skb, br, vid, p, msg);
174 }
175
176 switch (pkt_type) {
177 case BR_PKT_MULTICAST:
178 mdst = br_mdb_get(brmctx, skb, vid);
179 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
180 br_multicast_querier_exists(brmctx, eth_hdr(skb), mdst)) {
181 if ((mdst && mdst->host_joined) ||
182 br_multicast_is_router(brmctx, skb)) {
183 local_rcv = true;
184 br->dev->stats.multicast++;
185 }
186 mcast_hit = true;
187 } else {
188 local_rcv = true;
189 br->dev->stats.multicast++;
190 }
191 break;
192 case BR_PKT_UNICAST:
193 dst = br_fdb_find_rcu(br, eth_hdr(skb)->h_dest, vid);
194 break;
195 default:
196 break;
197 }
198
199 if (dst) {
200 unsigned long now = jiffies;
201
202 if (test_bit(BR_FDB_LOCAL, &dst->flags))
203 return br_pass_frame_up(skb);
204
205 if (now != dst->used)
206 dst->used = now;
207 br_forward(dst->dst, skb, local_rcv, false);
208 } else {
209 if (!mcast_hit)
210 br_flood(br, skb, pkt_type, local_rcv, false);
211 else
212 br_multicast_flood(mdst, skb, brmctx, local_rcv, false);
213 }
214
215 if (local_rcv)
216 return br_pass_frame_up(skb);
217
218out:
219 return 0;
220drop:
221 kfree_skb(skb);
222 goto out;
223}
224EXPORT_SYMBOL_GPL(br_handle_frame_finish);
225
226static void __br_handle_local_finish(struct sk_buff *skb)
227{
228 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
229 u16 vid = 0;
230
231 /* check if vlan is allowed, to avoid spoofing */
232 if ((p->flags & BR_LEARNING) &&
233 nbp_state_should_learn(p) &&
234 !br_opt_get(p->br, BROPT_NO_LL_LEARN) &&
235 br_should_learn(p, skb, &vid))
236 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, 0);
237}
238
239/* note: already called with rcu_read_lock */
240static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
241{
242 __br_handle_local_finish(skb);
243
244 /* return 1 to signal the okfn() was called so it's ok to use the skb */
245 return 1;
246}
247
248static int nf_hook_bridge_pre(struct sk_buff *skb, struct sk_buff **pskb)
249{
250#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
251 struct nf_hook_entries *e = NULL;
252 struct nf_hook_state state;
253 unsigned int verdict, i;
254 struct net *net;
255 int ret;
256
257 net = dev_net(skb->dev);
258#ifdef HAVE_JUMP_LABEL
259 if (!static_key_false(&nf_hooks_needed[NFPROTO_BRIDGE][NF_BR_PRE_ROUTING]))
260 goto frame_finish;
261#endif
262
263 e = rcu_dereference(net->nf.hooks_bridge[NF_BR_PRE_ROUTING]);
264 if (!e)
265 goto frame_finish;
266
267 nf_hook_state_init(&state, NF_BR_PRE_ROUTING,
268 NFPROTO_BRIDGE, skb->dev, NULL, NULL,
269 net, br_handle_frame_finish);
270
271 for (i = 0; i < e->num_hook_entries; i++) {
272 verdict = nf_hook_entry_hookfn(&e->hooks[i], skb, &state);
273 switch (verdict & NF_VERDICT_MASK) {
274 case NF_ACCEPT:
275 if (BR_INPUT_SKB_CB(skb)->br_netfilter_broute) {
276 *pskb = skb;
277 return RX_HANDLER_PASS;
278 }
279 break;
280 case NF_DROP:
281 kfree_skb(skb);
282 return RX_HANDLER_CONSUMED;
283 case NF_QUEUE:
284 ret = nf_queue(skb, &state, i, verdict);
285 if (ret == 1)
286 continue;
287 return RX_HANDLER_CONSUMED;
288 default: /* STOLEN */
289 return RX_HANDLER_CONSUMED;
290 }
291 }
292frame_finish:
293 net = dev_net(skb->dev);
294 br_handle_frame_finish(net, NULL, skb);
295#else
296 br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
297#endif
298 return RX_HANDLER_CONSUMED;
299}
300
301/* Return 0 if the frame was not processed otherwise 1
302 * note: already called with rcu_read_lock
303 */
304static int br_process_frame_type(struct net_bridge_port *p,
305 struct sk_buff *skb)
306{
307 struct br_frame_type *tmp;
308
309 hlist_for_each_entry_rcu(tmp, &p->br->frame_type_list, list)
310 if (unlikely(tmp->type == skb->protocol))
311 return tmp->frame_handler(p, skb);
312
313 return 0;
314}
315
316/*
317 * Return NULL if skb is handled
318 * note: already called with rcu_read_lock
319 */
320static rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
321{
322 struct net_bridge_port *p;
323 struct sk_buff *skb = *pskb;
324 const unsigned char *dest = eth_hdr(skb)->h_dest;
325
326 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
327 return RX_HANDLER_PASS;
328
329 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
330 goto drop;
331
332 skb = skb_share_check(skb, GFP_ATOMIC);
333 if (!skb)
334 return RX_HANDLER_CONSUMED;
335
336 memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
337
338 p = br_port_get_rcu(skb->dev);
339 if (p->flags & BR_VLAN_TUNNEL)
340 br_handle_ingress_vlan_tunnel(skb, p, nbp_vlan_group_rcu(p));
341
342 if (unlikely(is_link_local_ether_addr(dest))) {
343 u16 fwd_mask = p->br->group_fwd_mask_required;
344
345 /*
346 * See IEEE 802.1D Table 7-10 Reserved addresses
347 *
348 * Assignment Value
349 * Bridge Group Address 01-80-C2-00-00-00
350 * (MAC Control) 802.3 01-80-C2-00-00-01
351 * (Link Aggregation) 802.3 01-80-C2-00-00-02
352 * 802.1X PAE address 01-80-C2-00-00-03
353 *
354 * 802.1AB LLDP 01-80-C2-00-00-0E
355 *
356 * Others reserved for future standardization
357 */
358 fwd_mask |= p->group_fwd_mask;
359 switch (dest[5]) {
360 case 0x00: /* Bridge Group Address */
361 /* If STP is turned off,
362 then must forward to keep loop detection */
363 if (p->br->stp_enabled == BR_NO_STP ||
364 fwd_mask & (1u << dest[5]))
365 goto forward;
366 *pskb = skb;
367 __br_handle_local_finish(skb);
368 return RX_HANDLER_PASS;
369
370 case 0x01: /* IEEE MAC (Pause) */
371 goto drop;
372
373 case 0x0E: /* 802.1AB LLDP */
374 fwd_mask |= p->br->group_fwd_mask;
375 if (fwd_mask & (1u << dest[5]))
376 goto forward;
377 *pskb = skb;
378 __br_handle_local_finish(skb);
379 return RX_HANDLER_PASS;
380
381 default:
382 /* Allow selective forwarding for most other protocols */
383 fwd_mask |= p->br->group_fwd_mask;
384 if (fwd_mask & (1u << dest[5]))
385 goto forward;
386 }
387
388 /* The else clause should be hit when nf_hook():
389 * - returns < 0 (drop/error)
390 * - returns = 0 (stolen/nf_queue)
391 * Thus return 1 from the okfn() to signal the skb is ok to pass
392 */
393 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
394 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
395 br_handle_local_finish) == 1) {
396 return RX_HANDLER_PASS;
397 } else {
398 return RX_HANDLER_CONSUMED;
399 }
400 }
401
402 if (unlikely(br_process_frame_type(p, skb)))
403 return RX_HANDLER_PASS;
404
405forward:
406 if (br_mst_is_enabled(p->br))
407 goto defer_stp_filtering;
408
409 switch (p->state) {
410 case BR_STATE_FORWARDING:
411 case BR_STATE_LEARNING:
412defer_stp_filtering:
413 if (ether_addr_equal(p->br->dev->dev_addr, dest))
414 skb->pkt_type = PACKET_HOST;
415
416 return nf_hook_bridge_pre(skb, pskb);
417 default:
418drop:
419 kfree_skb(skb);
420 }
421 return RX_HANDLER_CONSUMED;
422}
423
424/* This function has no purpose other than to appease the br_port_get_rcu/rtnl
425 * helpers which identify bridged ports according to the rx_handler installed
426 * on them (so there _needs_ to be a bridge rx_handler even if we don't need it
427 * to do anything useful). This bridge won't support traffic to/from the stack,
428 * but only hardware bridging. So return RX_HANDLER_PASS so we don't steal
429 * frames from the ETH_P_XDSA packet_type handler.
430 */
431static rx_handler_result_t br_handle_frame_dummy(struct sk_buff **pskb)
432{
433 return RX_HANDLER_PASS;
434}
435
436rx_handler_func_t *br_get_rx_handler(const struct net_device *dev)
437{
438 if (netdev_uses_dsa(dev))
439 return br_handle_frame_dummy;
440
441 return br_handle_frame;
442}
443
444void br_add_frame(struct net_bridge *br, struct br_frame_type *ft)
445{
446 hlist_add_head_rcu(&ft->list, &br->frame_type_list);
447}
448
449void br_del_frame(struct net_bridge *br, struct br_frame_type *ft)
450{
451 struct br_frame_type *tmp;
452
453 hlist_for_each_entry(tmp, &br->frame_type_list, list)
454 if (ft == tmp) {
455 hlist_del_rcu(&ft->list);
456 return;
457 }
458}