Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
24static int deliver_clone(const struct net_bridge_port *prev,
25 struct sk_buff *skb,
26 void (*__packet_hook)(const struct net_bridge_port *p,
27 struct sk_buff *skb));
28
29/* Don't forward packets to originating port or forwarding disabled */
30static inline int should_deliver(const struct net_bridge_port *p,
31 const struct sk_buff *skb)
32{
33 return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
34 br_allowed_egress(p->br, nbp_get_vlan_info(p), skb) &&
35 p->state == BR_STATE_FORWARDING;
36}
37
38int br_dev_queue_push_xmit(struct sk_buff *skb)
39{
40 /* ip_fragment doesn't copy the MAC header */
41 if (nf_bridge_maybe_copy_header(skb) ||
42 !is_skb_forwardable(skb->dev, skb)) {
43 kfree_skb(skb);
44 } else {
45 skb_push(skb, ETH_HLEN);
46 br_drop_fake_rtable(skb);
47 dev_queue_xmit(skb);
48 }
49
50 return 0;
51}
52
53int br_forward_finish(struct sk_buff *skb)
54{
55 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
56 br_dev_queue_push_xmit);
57
58}
59
60static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
61{
62 skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
63 if (!skb)
64 return;
65
66 skb->dev = to->dev;
67
68 if (unlikely(netpoll_tx_running(to->br->dev))) {
69 if (!is_skb_forwardable(skb->dev, skb))
70 kfree_skb(skb);
71 else {
72 skb_push(skb, ETH_HLEN);
73 br_netpoll_send_skb(to, skb);
74 }
75 return;
76 }
77
78 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
79 br_forward_finish);
80}
81
82static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
83{
84 struct net_device *indev;
85
86 if (skb_warn_if_lro(skb)) {
87 kfree_skb(skb);
88 return;
89 }
90
91 skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
92 if (!skb)
93 return;
94
95 indev = skb->dev;
96 skb->dev = to->dev;
97 skb_forward_csum(skb);
98
99 NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
100 br_forward_finish);
101}
102
103/* called with rcu_read_lock */
104void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
105{
106 if (to && should_deliver(to, skb)) {
107 __br_deliver(to, skb);
108 return;
109 }
110
111 kfree_skb(skb);
112}
113
114/* called with rcu_read_lock */
115void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
116{
117 if (should_deliver(to, skb)) {
118 if (skb0)
119 deliver_clone(to, skb, __br_forward);
120 else
121 __br_forward(to, skb);
122 return;
123 }
124
125 if (!skb0)
126 kfree_skb(skb);
127}
128
129static int deliver_clone(const struct net_bridge_port *prev,
130 struct sk_buff *skb,
131 void (*__packet_hook)(const struct net_bridge_port *p,
132 struct sk_buff *skb))
133{
134 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
135
136 skb = skb_clone(skb, GFP_ATOMIC);
137 if (!skb) {
138 dev->stats.tx_dropped++;
139 return -ENOMEM;
140 }
141
142 __packet_hook(prev, skb);
143 return 0;
144}
145
146static struct net_bridge_port *maybe_deliver(
147 struct net_bridge_port *prev, struct net_bridge_port *p,
148 struct sk_buff *skb,
149 void (*__packet_hook)(const struct net_bridge_port *p,
150 struct sk_buff *skb))
151{
152 int err;
153
154 if (!should_deliver(p, skb))
155 return prev;
156
157 if (!prev)
158 goto out;
159
160 err = deliver_clone(prev, skb, __packet_hook);
161 if (err)
162 return ERR_PTR(err);
163
164out:
165 return p;
166}
167
168/* called under bridge lock */
169static void br_flood(struct net_bridge *br, struct sk_buff *skb,
170 struct sk_buff *skb0,
171 void (*__packet_hook)(const struct net_bridge_port *p,
172 struct sk_buff *skb),
173 bool unicast)
174{
175 struct net_bridge_port *p;
176 struct net_bridge_port *prev;
177
178 prev = NULL;
179
180 list_for_each_entry_rcu(p, &br->port_list, list) {
181 /* Do not flood unicast traffic to ports that turn it off */
182 if (unicast && !(p->flags & BR_FLOOD))
183 continue;
184 prev = maybe_deliver(prev, p, skb, __packet_hook);
185 if (IS_ERR(prev))
186 goto out;
187 }
188
189 if (!prev)
190 goto out;
191
192 if (skb0)
193 deliver_clone(prev, skb, __packet_hook);
194 else
195 __packet_hook(prev, skb);
196 return;
197
198out:
199 if (!skb0)
200 kfree_skb(skb);
201}
202
203
204/* called with rcu_read_lock */
205void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, bool unicast)
206{
207 br_flood(br, skb, NULL, __br_deliver, unicast);
208}
209
210/* called under bridge lock */
211void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
212 struct sk_buff *skb2, bool unicast)
213{
214 br_flood(br, skb, skb2, __br_forward, unicast);
215}
216
217#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
218/* called with rcu_read_lock */
219static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
220 struct sk_buff *skb, struct sk_buff *skb0,
221 void (*__packet_hook)(
222 const struct net_bridge_port *p,
223 struct sk_buff *skb))
224{
225 struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
226 struct net_bridge *br = netdev_priv(dev);
227 struct net_bridge_port *prev = NULL;
228 struct net_bridge_port_group *p;
229 struct hlist_node *rp;
230
231 rp = rcu_dereference(hlist_first_rcu(&br->router_list));
232 p = mdst ? rcu_dereference(mdst->ports) : NULL;
233 while (p || rp) {
234 struct net_bridge_port *port, *lport, *rport;
235
236 lport = p ? p->port : NULL;
237 rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
238 NULL;
239
240 port = (unsigned long)lport > (unsigned long)rport ?
241 lport : rport;
242
243 prev = maybe_deliver(prev, port, skb, __packet_hook);
244 if (IS_ERR(prev))
245 goto out;
246
247 if ((unsigned long)lport >= (unsigned long)port)
248 p = rcu_dereference(p->next);
249 if ((unsigned long)rport >= (unsigned long)port)
250 rp = rcu_dereference(hlist_next_rcu(rp));
251 }
252
253 if (!prev)
254 goto out;
255
256 if (skb0)
257 deliver_clone(prev, skb, __packet_hook);
258 else
259 __packet_hook(prev, skb);
260 return;
261
262out:
263 if (!skb0)
264 kfree_skb(skb);
265}
266
267/* called with rcu_read_lock */
268void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
269 struct sk_buff *skb)
270{
271 br_multicast_flood(mdst, skb, NULL, __br_deliver);
272}
273
274/* called with rcu_read_lock */
275void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
276 struct sk_buff *skb, struct sk_buff *skb2)
277{
278 br_multicast_flood(mdst, skb, skb2, __br_forward);
279}
280#endif