bridge: allow changing hardware address to any valid address
[linux-2.6-block.git] / net / bridge / br_fdb.c
CommitLineData
1da177e4
LT
1/*
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>
3f890923 23#include <linux/random.h>
1da177e4 24#include <asm/atomic.h>
3f890923 25#include <asm/unaligned.h>
1da177e4
LT
26#include "br_private.h"
27
e18b890b 28static struct kmem_cache *br_fdb_cache __read_mostly;
1da177e4
LT
29static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
30 const unsigned char *addr);
31
3f890923
SH
32static u32 fdb_salt __read_mostly;
33
1da177e4
LT
34void __init br_fdb_init(void)
35{
36 br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
37 sizeof(struct net_bridge_fdb_entry),
38 0,
39 SLAB_HWCACHE_ALIGN, NULL, NULL);
3f890923 40 get_random_bytes(&fdb_salt, sizeof(fdb_salt));
1da177e4
LT
41}
42
43void __exit br_fdb_fini(void)
44{
45 kmem_cache_destroy(br_fdb_cache);
46}
47
48
49/* if topology_changing then use forward_delay (default 15 sec)
50 * otherwise keep longer (default 5 minutes)
51 */
3f890923 52static inline unsigned long hold_time(const struct net_bridge *br)
1da177e4
LT
53{
54 return br->topology_change ? br->forward_delay : br->ageing_time;
55}
56
3f890923 57static inline int has_expired(const struct net_bridge *br,
1da177e4
LT
58 const struct net_bridge_fdb_entry *fdb)
59{
9d6f229f 60 return !fdb->is_static
1da177e4
LT
61 && time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
62}
63
3f890923 64static inline int br_mac_hash(const unsigned char *mac)
1da177e4 65{
3f890923
SH
66 /* use 1 byte of OUI cnd 3 bytes of NIC */
67 u32 key = get_unaligned((u32 *)(mac + 2));
68 return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
1da177e4
LT
69}
70
3f890923 71static inline void fdb_delete(struct net_bridge_fdb_entry *f)
1da177e4
LT
72{
73 hlist_del_rcu(&f->hlist);
74 br_fdb_put(f);
75}
76
77void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
78{
79 struct net_bridge *br = p->br;
80 int i;
9d6f229f 81
1da177e4
LT
82 spin_lock_bh(&br->hash_lock);
83
84 /* Search all chains since old address/hash is unknown */
85 for (i = 0; i < BR_HASH_SIZE; i++) {
86 struct hlist_node *h;
87 hlist_for_each(h, &br->hash[i]) {
88 struct net_bridge_fdb_entry *f;
89
90 f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
91 if (f->dst == p && f->is_local) {
92 /* maybe another port has same hw addr? */
93 struct net_bridge_port *op;
94 list_for_each_entry(op, &br->port_list, list) {
9d6f229f 95 if (op != p &&
6ede2463
SH
96 !compare_ether_addr(op->dev->dev_addr,
97 f->addr.addr)) {
1da177e4
LT
98 f->dst = op;
99 goto insert;
100 }
101 }
102
103 /* delete old one */
104 fdb_delete(f);
105 goto insert;
106 }
107 }
108 }
109 insert:
110 /* insert new address, may fail if invalid address or dup. */
111 fdb_insert(br, p, newaddr);
112
113 spin_unlock_bh(&br->hash_lock);
114}
115
116void br_fdb_cleanup(unsigned long _data)
117{
118 struct net_bridge *br = (struct net_bridge *)_data;
119 unsigned long delay = hold_time(br);
120 int i;
121
122 spin_lock_bh(&br->hash_lock);
123 for (i = 0; i < BR_HASH_SIZE; i++) {
124 struct net_bridge_fdb_entry *f;
125 struct hlist_node *h, *n;
126
127 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
9d6f229f
YH
128 if (!f->is_static &&
129 time_before_eq(f->ageing_timer + delay, jiffies))
1da177e4
LT
130 fdb_delete(f);
131 }
132 }
133 spin_unlock_bh(&br->hash_lock);
134
135 mod_timer(&br->gc_timer, jiffies + HZ/10);
136}
137
9cf63747
SH
138/* Completely flush all dynamic entries in forwarding database.*/
139void br_fdb_flush(struct net_bridge *br)
140{
141 int i;
142
143 spin_lock_bh(&br->hash_lock);
144 for (i = 0; i < BR_HASH_SIZE; i++) {
145 struct net_bridge_fdb_entry *f;
146 struct hlist_node *h, *n;
147 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
148 if (!f->is_static)
149 fdb_delete(f);
150 }
151 }
152 spin_unlock_bh(&br->hash_lock);
153}
1a620698 154
9cf63747
SH
155/* Flush all entries refering to a specific port.
156 * if do_all is set also flush static entries
157 */
1a620698
SH
158void br_fdb_delete_by_port(struct net_bridge *br,
159 const struct net_bridge_port *p,
160 int do_all)
1da177e4
LT
161{
162 int i;
163
164 spin_lock_bh(&br->hash_lock);
165 for (i = 0; i < BR_HASH_SIZE; i++) {
166 struct hlist_node *h, *g;
9d6f229f 167
1da177e4
LT
168 hlist_for_each_safe(h, g, &br->hash[i]) {
169 struct net_bridge_fdb_entry *f
170 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
9d6f229f 171 if (f->dst != p)
1da177e4
LT
172 continue;
173
1a620698
SH
174 if (f->is_static && !do_all)
175 continue;
1da177e4
LT
176 /*
177 * if multiple ports all have the same device address
178 * then when one port is deleted, assign
179 * the local entry to other port
180 */
181 if (f->is_local) {
182 struct net_bridge_port *op;
183 list_for_each_entry(op, &br->port_list, list) {
9d6f229f 184 if (op != p &&
6ede2463
SH
185 !compare_ether_addr(op->dev->dev_addr,
186 f->addr.addr)) {
1da177e4
LT
187 f->dst = op;
188 goto skip_delete;
189 }
190 }
191 }
192
193 fdb_delete(f);
194 skip_delete: ;
195 }
196 }
197 spin_unlock_bh(&br->hash_lock);
198}
199
200/* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
201struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
202 const unsigned char *addr)
203{
204 struct hlist_node *h;
205 struct net_bridge_fdb_entry *fdb;
206
207 hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
6ede2463 208 if (!compare_ether_addr(fdb->addr.addr, addr)) {
1da177e4
LT
209 if (unlikely(has_expired(br, fdb)))
210 break;
211 return fdb;
212 }
213 }
214
215 return NULL;
216}
217
218/* Interface used by ATM hook that keeps a ref count */
9d6f229f 219struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
1da177e4
LT
220 unsigned char *addr)
221{
222 struct net_bridge_fdb_entry *fdb;
223
224 rcu_read_lock();
225 fdb = __br_fdb_get(br, addr);
b19cbe2a
PM
226 if (fdb && !atomic_inc_not_zero(&fdb->use_count))
227 fdb = NULL;
1da177e4
LT
228 rcu_read_unlock();
229 return fdb;
230}
231
232static void fdb_rcu_free(struct rcu_head *head)
233{
234 struct net_bridge_fdb_entry *ent
235 = container_of(head, struct net_bridge_fdb_entry, rcu);
236 kmem_cache_free(br_fdb_cache, ent);
237}
238
239/* Set entry up for deletion with RCU */
240void br_fdb_put(struct net_bridge_fdb_entry *ent)
241{
242 if (atomic_dec_and_test(&ent->use_count))
243 call_rcu(&ent->rcu, fdb_rcu_free);
244}
245
246/*
9d6f229f 247 * Fill buffer with forwarding table records in
1da177e4
LT
248 * the API format.
249 */
250int br_fdb_fillbuf(struct net_bridge *br, void *buf,
251 unsigned long maxnum, unsigned long skip)
252{
253 struct __fdb_entry *fe = buf;
254 int i, num = 0;
255 struct hlist_node *h;
256 struct net_bridge_fdb_entry *f;
257
258 memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
259
260 rcu_read_lock();
261 for (i = 0; i < BR_HASH_SIZE; i++) {
262 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
263 if (num >= maxnum)
264 goto out;
265
9d6f229f 266 if (has_expired(br, f))
1da177e4
LT
267 continue;
268
269 if (skip) {
270 --skip;
271 continue;
272 }
273
274 /* convert from internal format to API */
275 memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
276 fe->port_no = f->dst->port_no;
277 fe->is_local = f->is_local;
278 if (!f->is_static)
279 fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
280 ++fe;
281 ++num;
282 }
283 }
284
285 out:
286 rcu_read_unlock();
287
288 return num;
289}
290
291static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
292 const unsigned char *addr)
293{
294 struct hlist_node *h;
295 struct net_bridge_fdb_entry *fdb;
296
297 hlist_for_each_entry_rcu(fdb, h, head, hlist) {
6ede2463 298 if (!compare_ether_addr(fdb->addr.addr, addr))
1da177e4
LT
299 return fdb;
300 }
301 return NULL;
302}
303
304static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
305 struct net_bridge_port *source,
9d6f229f 306 const unsigned char *addr,
1da177e4
LT
307 int is_local)
308{
309 struct net_bridge_fdb_entry *fdb;
310
311 fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
312 if (fdb) {
313 memcpy(fdb->addr.addr, addr, ETH_ALEN);
314 atomic_set(&fdb->use_count, 1);
315 hlist_add_head_rcu(&fdb->hlist, head);
316
317 fdb->dst = source;
318 fdb->is_local = is_local;
319 fdb->is_static = is_local;
320 fdb->ageing_timer = jiffies;
321 }
322 return fdb;
323}
324
325static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
326 const unsigned char *addr)
327{
328 struct hlist_head *head = &br->hash[br_mac_hash(addr)];
329 struct net_bridge_fdb_entry *fdb;
330
331 if (!is_valid_ether_addr(addr))
332 return -EINVAL;
333
334 fdb = fdb_find(head, addr);
335 if (fdb) {
9d6f229f 336 /* it is okay to have multiple ports with same
1da177e4
LT
337 * address, just use the first one.
338 */
9d6f229f 339 if (fdb->is_local)
1da177e4
LT
340 return 0;
341
342 printk(KERN_WARNING "%s adding interface with same address "
343 "as a received packet\n",
344 source->dev->name);
345 fdb_delete(fdb);
9d6f229f 346 }
1da177e4
LT
347
348 if (!fdb_create(head, source, addr, 1))
349 return -ENOMEM;
350
351 return 0;
352}
353
354int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
355 const unsigned char *addr)
356{
357 int ret;
358
359 spin_lock_bh(&br->hash_lock);
360 ret = fdb_insert(br, source, addr);
361 spin_unlock_bh(&br->hash_lock);
362 return ret;
363}
364
365void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
366 const unsigned char *addr)
367{
368 struct hlist_head *head = &br->hash[br_mac_hash(addr)];
369 struct net_bridge_fdb_entry *fdb;
370
371 /* some users want to always flood. */
372 if (hold_time(br) == 0)
373 return;
374
1da177e4
LT
375 fdb = fdb_find(head, addr);
376 if (likely(fdb)) {
377 /* attempt to update an entry for a local interface */
378 if (unlikely(fdb->is_local)) {
9d6f229f 379 if (net_ratelimit())
1da177e4
LT
380 printk(KERN_WARNING "%s: received packet with "
381 " own address as source address\n",
382 source->dev->name);
383 } else {
384 /* fastpath: update of existing entry */
385 fdb->dst = source;
386 fdb->ageing_timer = jiffies;
387 }
388 } else {
f8ae737d 389 spin_lock(&br->hash_lock);
1da177e4
LT
390 if (!fdb_find(head, addr))
391 fdb_create(head, source, addr, 0);
392 /* else we lose race and someone else inserts
393 * it first, don't bother updating
394 */
f8ae737d 395 spin_unlock(&br->hash_lock);
1da177e4 396 }
1da177e4 397}