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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Forwarding database
3 * Linux ethernet bridge
4 *
5 * Authors:
6 * Lennert Buytenhek <buytenh@gnu.org>
7 *
8 * $Id: br_fdb.c,v 1.6 2002/01/17 00:57:07 davem Exp $
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16#include <linux/kernel.h>
17#include <linux/init.h>
18#include <linux/spinlock.h>
19#include <linux/times.h>
20#include <linux/netdevice.h>
21#include <linux/etherdevice.h>
22#include <linux/jhash.h>
23#include <asm/atomic.h>
24#include "br_private.h"
25
Eric Dumazetba899662005-08-26 12:05:31 -070026static kmem_cache_t *br_fdb_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070027static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
28 const unsigned char *addr);
29
30void __init br_fdb_init(void)
31{
32 br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
33 sizeof(struct net_bridge_fdb_entry),
34 0,
35 SLAB_HWCACHE_ALIGN, NULL, NULL);
36}
37
38void __exit br_fdb_fini(void)
39{
40 kmem_cache_destroy(br_fdb_cache);
41}
42
43
44/* if topology_changing then use forward_delay (default 15 sec)
45 * otherwise keep longer (default 5 minutes)
46 */
47static __inline__ unsigned long hold_time(const struct net_bridge *br)
48{
49 return br->topology_change ? br->forward_delay : br->ageing_time;
50}
51
52static __inline__ int has_expired(const struct net_bridge *br,
53 const struct net_bridge_fdb_entry *fdb)
54{
55 return !fdb->is_static
56 && time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
57}
58
59static __inline__ int br_mac_hash(const unsigned char *mac)
60{
61 return jhash(mac, ETH_ALEN, 0) & (BR_HASH_SIZE - 1);
62}
63
64static __inline__ void fdb_delete(struct net_bridge_fdb_entry *f)
65{
66 hlist_del_rcu(&f->hlist);
67 br_fdb_put(f);
68}
69
70void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
71{
72 struct net_bridge *br = p->br;
73 int i;
74
75 spin_lock_bh(&br->hash_lock);
76
77 /* Search all chains since old address/hash is unknown */
78 for (i = 0; i < BR_HASH_SIZE; i++) {
79 struct hlist_node *h;
80 hlist_for_each(h, &br->hash[i]) {
81 struct net_bridge_fdb_entry *f;
82
83 f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
84 if (f->dst == p && f->is_local) {
85 /* maybe another port has same hw addr? */
86 struct net_bridge_port *op;
87 list_for_each_entry(op, &br->port_list, list) {
88 if (op != p &&
Stephen Hemminger6ede2462005-10-25 15:04:59 -070089 !compare_ether_addr(op->dev->dev_addr,
90 f->addr.addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 f->dst = op;
92 goto insert;
93 }
94 }
95
96 /* delete old one */
97 fdb_delete(f);
98 goto insert;
99 }
100 }
101 }
102 insert:
103 /* insert new address, may fail if invalid address or dup. */
104 fdb_insert(br, p, newaddr);
105
106 spin_unlock_bh(&br->hash_lock);
107}
108
109void br_fdb_cleanup(unsigned long _data)
110{
111 struct net_bridge *br = (struct net_bridge *)_data;
112 unsigned long delay = hold_time(br);
113 int i;
114
115 spin_lock_bh(&br->hash_lock);
116 for (i = 0; i < BR_HASH_SIZE; i++) {
117 struct net_bridge_fdb_entry *f;
118 struct hlist_node *h, *n;
119
120 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
121 if (!f->is_static &&
122 time_before_eq(f->ageing_timer + delay, jiffies))
123 fdb_delete(f);
124 }
125 }
126 spin_unlock_bh(&br->hash_lock);
127
128 mod_timer(&br->gc_timer, jiffies + HZ/10);
129}
130
131void br_fdb_delete_by_port(struct net_bridge *br, struct net_bridge_port *p)
132{
133 int i;
134
135 spin_lock_bh(&br->hash_lock);
136 for (i = 0; i < BR_HASH_SIZE; i++) {
137 struct hlist_node *h, *g;
138
139 hlist_for_each_safe(h, g, &br->hash[i]) {
140 struct net_bridge_fdb_entry *f
141 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
142 if (f->dst != p)
143 continue;
144
145 /*
146 * if multiple ports all have the same device address
147 * then when one port is deleted, assign
148 * the local entry to other port
149 */
150 if (f->is_local) {
151 struct net_bridge_port *op;
152 list_for_each_entry(op, &br->port_list, list) {
153 if (op != p &&
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700154 !compare_ether_addr(op->dev->dev_addr,
155 f->addr.addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 f->dst = op;
157 goto skip_delete;
158 }
159 }
160 }
161
162 fdb_delete(f);
163 skip_delete: ;
164 }
165 }
166 spin_unlock_bh(&br->hash_lock);
167}
168
169/* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
170struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
171 const unsigned char *addr)
172{
173 struct hlist_node *h;
174 struct net_bridge_fdb_entry *fdb;
175
176 hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700177 if (!compare_ether_addr(fdb->addr.addr, addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 if (unlikely(has_expired(br, fdb)))
179 break;
180 return fdb;
181 }
182 }
183
184 return NULL;
185}
186
187/* Interface used by ATM hook that keeps a ref count */
188struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
189 unsigned char *addr)
190{
191 struct net_bridge_fdb_entry *fdb;
192
193 rcu_read_lock();
194 fdb = __br_fdb_get(br, addr);
195 if (fdb)
196 atomic_inc(&fdb->use_count);
197 rcu_read_unlock();
198 return fdb;
199}
200
201static void fdb_rcu_free(struct rcu_head *head)
202{
203 struct net_bridge_fdb_entry *ent
204 = container_of(head, struct net_bridge_fdb_entry, rcu);
205 kmem_cache_free(br_fdb_cache, ent);
206}
207
208/* Set entry up for deletion with RCU */
209void br_fdb_put(struct net_bridge_fdb_entry *ent)
210{
211 if (atomic_dec_and_test(&ent->use_count))
212 call_rcu(&ent->rcu, fdb_rcu_free);
213}
214
215/*
216 * Fill buffer with forwarding table records in
217 * the API format.
218 */
219int br_fdb_fillbuf(struct net_bridge *br, void *buf,
220 unsigned long maxnum, unsigned long skip)
221{
222 struct __fdb_entry *fe = buf;
223 int i, num = 0;
224 struct hlist_node *h;
225 struct net_bridge_fdb_entry *f;
226
227 memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
228
229 rcu_read_lock();
230 for (i = 0; i < BR_HASH_SIZE; i++) {
231 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
232 if (num >= maxnum)
233 goto out;
234
235 if (has_expired(br, f))
236 continue;
237
238 if (skip) {
239 --skip;
240 continue;
241 }
242
243 /* convert from internal format to API */
244 memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
245 fe->port_no = f->dst->port_no;
246 fe->is_local = f->is_local;
247 if (!f->is_static)
248 fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
249 ++fe;
250 ++num;
251 }
252 }
253
254 out:
255 rcu_read_unlock();
256
257 return num;
258}
259
260static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
261 const unsigned char *addr)
262{
263 struct hlist_node *h;
264 struct net_bridge_fdb_entry *fdb;
265
266 hlist_for_each_entry_rcu(fdb, h, head, hlist) {
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700267 if (!compare_ether_addr(fdb->addr.addr, addr))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 return fdb;
269 }
270 return NULL;
271}
272
273static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
274 struct net_bridge_port *source,
275 const unsigned char *addr,
276 int is_local)
277{
278 struct net_bridge_fdb_entry *fdb;
279
280 fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
281 if (fdb) {
282 memcpy(fdb->addr.addr, addr, ETH_ALEN);
283 atomic_set(&fdb->use_count, 1);
284 hlist_add_head_rcu(&fdb->hlist, head);
285
286 fdb->dst = source;
287 fdb->is_local = is_local;
288 fdb->is_static = is_local;
289 fdb->ageing_timer = jiffies;
290 }
291 return fdb;
292}
293
294static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
295 const unsigned char *addr)
296{
297 struct hlist_head *head = &br->hash[br_mac_hash(addr)];
298 struct net_bridge_fdb_entry *fdb;
299
300 if (!is_valid_ether_addr(addr))
301 return -EINVAL;
302
303 fdb = fdb_find(head, addr);
304 if (fdb) {
305 /* it is okay to have multiple ports with same
306 * address, just use the first one.
307 */
308 if (fdb->is_local)
309 return 0;
310
311 printk(KERN_WARNING "%s adding interface with same address "
312 "as a received packet\n",
313 source->dev->name);
314 fdb_delete(fdb);
315 }
316
317 if (!fdb_create(head, source, addr, 1))
318 return -ENOMEM;
319
320 return 0;
321}
322
323int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
324 const unsigned char *addr)
325{
326 int ret;
327
328 spin_lock_bh(&br->hash_lock);
329 ret = fdb_insert(br, source, addr);
330 spin_unlock_bh(&br->hash_lock);
331 return ret;
332}
333
334void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
335 const unsigned char *addr)
336{
337 struct hlist_head *head = &br->hash[br_mac_hash(addr)];
338 struct net_bridge_fdb_entry *fdb;
339
340 /* some users want to always flood. */
341 if (hold_time(br) == 0)
342 return;
343
344 rcu_read_lock();
345 fdb = fdb_find(head, addr);
346 if (likely(fdb)) {
347 /* attempt to update an entry for a local interface */
348 if (unlikely(fdb->is_local)) {
349 if (net_ratelimit())
350 printk(KERN_WARNING "%s: received packet with "
351 " own address as source address\n",
352 source->dev->name);
353 } else {
354 /* fastpath: update of existing entry */
355 fdb->dst = source;
356 fdb->ageing_timer = jiffies;
357 }
358 } else {
359 spin_lock_bh(&br->hash_lock);
360 if (!fdb_find(head, addr))
361 fdb_create(head, source, addr, 0);
362 /* else we lose race and someone else inserts
363 * it first, don't bother updating
364 */
365 spin_unlock_bh(&br->hash_lock);
366 }
367 rcu_read_unlock();
368}