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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>
Stephen Hemminger3f890922007-03-21 13:42:33 -070023#include <linux/random.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <asm/atomic.h>
Stephen Hemminger3f890922007-03-21 13:42:33 -070025#include <asm/unaligned.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include "br_private.h"
27
Christoph Lametere18b8902006-12-06 20:33:20 -080028static struct kmem_cache *br_fdb_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070029static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
30 const unsigned char *addr);
31
Stephen Hemminger3f890922007-03-21 13:42:33 -070032static u32 fdb_salt __read_mostly;
33
Akinobu Mita87a596e2007-04-07 18:57:07 +090034int __init br_fdb_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070035{
36 br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
37 sizeof(struct net_bridge_fdb_entry),
38 0,
Paul Mundt20c2df82007-07-20 10:11:58 +090039 SLAB_HWCACHE_ALIGN, NULL);
Akinobu Mita87a596e2007-04-07 18:57:07 +090040 if (!br_fdb_cache)
41 return -ENOMEM;
42
Stephen Hemminger3f890922007-03-21 13:42:33 -070043 get_random_bytes(&fdb_salt, sizeof(fdb_salt));
Akinobu Mita87a596e2007-04-07 18:57:07 +090044 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070045}
46
47void __exit br_fdb_fini(void)
48{
49 kmem_cache_destroy(br_fdb_cache);
50}
51
52
53/* if topology_changing then use forward_delay (default 15 sec)
54 * otherwise keep longer (default 5 minutes)
55 */
Stephen Hemminger3f890922007-03-21 13:42:33 -070056static inline unsigned long hold_time(const struct net_bridge *br)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057{
58 return br->topology_change ? br->forward_delay : br->ageing_time;
59}
60
Stephen Hemminger3f890922007-03-21 13:42:33 -070061static inline int has_expired(const struct net_bridge *br,
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 const struct net_bridge_fdb_entry *fdb)
63{
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +090064 return !fdb->is_static
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 && time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
66}
67
Stephen Hemminger3f890922007-03-21 13:42:33 -070068static inline int br_mac_hash(const unsigned char *mac)
Linus Torvalds1da177e2005-04-16 15:20:36 -070069{
Stephen Hemminger3f890922007-03-21 13:42:33 -070070 /* use 1 byte of OUI cnd 3 bytes of NIC */
71 u32 key = get_unaligned((u32 *)(mac + 2));
72 return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073}
74
Stephen Hemminger3f890922007-03-21 13:42:33 -070075static inline void fdb_delete(struct net_bridge_fdb_entry *f)
Linus Torvalds1da177e2005-04-16 15:20:36 -070076{
77 hlist_del_rcu(&f->hlist);
78 br_fdb_put(f);
79}
80
81void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
82{
83 struct net_bridge *br = p->br;
84 int i;
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +090085
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 spin_lock_bh(&br->hash_lock);
87
88 /* Search all chains since old address/hash is unknown */
89 for (i = 0; i < BR_HASH_SIZE; i++) {
90 struct hlist_node *h;
91 hlist_for_each(h, &br->hash[i]) {
92 struct net_bridge_fdb_entry *f;
93
94 f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
95 if (f->dst == p && f->is_local) {
96 /* maybe another port has same hw addr? */
97 struct net_bridge_port *op;
98 list_for_each_entry(op, &br->port_list, list) {
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +090099 if (op != p &&
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700100 !compare_ether_addr(op->dev->dev_addr,
101 f->addr.addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 f->dst = op;
103 goto insert;
104 }
105 }
106
107 /* delete old one */
108 fdb_delete(f);
109 goto insert;
110 }
111 }
112 }
113 insert:
114 /* insert new address, may fail if invalid address or dup. */
115 fdb_insert(br, p, newaddr);
116
117 spin_unlock_bh(&br->hash_lock);
118}
119
120void br_fdb_cleanup(unsigned long _data)
121{
122 struct net_bridge *br = (struct net_bridge *)_data;
123 unsigned long delay = hold_time(br);
Baruch Even071f7722007-05-31 01:20:45 -0700124 unsigned long next_timer = jiffies + br->forward_delay;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 int i;
126
127 spin_lock_bh(&br->hash_lock);
128 for (i = 0; i < BR_HASH_SIZE; i++) {
129 struct net_bridge_fdb_entry *f;
130 struct hlist_node *h, *n;
131
132 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
Baruch Even071f7722007-05-31 01:20:45 -0700133 unsigned long this_timer;
134 if (f->is_static)
135 continue;
136 this_timer = f->ageing_timer + delay;
137 if (time_before_eq(this_timer, jiffies))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 fdb_delete(f);
Baruch Even071f7722007-05-31 01:20:45 -0700139 else if (this_timer < next_timer)
140 next_timer = this_timer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 }
142 }
143 spin_unlock_bh(&br->hash_lock);
144
Baruch Even071f7722007-05-31 01:20:45 -0700145 /* Add HZ/4 to ensure we round the jiffies upwards to be after the next
146 * timer, otherwise we might round down and will have no-op run. */
147 mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148}
149
Stephen Hemminger9cf63742007-04-09 12:57:54 -0700150/* Completely flush all dynamic entries in forwarding database.*/
151void br_fdb_flush(struct net_bridge *br)
152{
153 int i;
Stephen Hemminger1a620692006-10-12 14:45:38 -0700154
Stephen Hemminger9cf63742007-04-09 12:57:54 -0700155 spin_lock_bh(&br->hash_lock);
156 for (i = 0; i < BR_HASH_SIZE; i++) {
157 struct net_bridge_fdb_entry *f;
158 struct hlist_node *h, *n;
159 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
160 if (!f->is_static)
161 fdb_delete(f);
162 }
163 }
164 spin_unlock_bh(&br->hash_lock);
165}
166
167/* Flush all entries refering to a specific port.
168 * if do_all is set also flush static entries
169 */
Stephen Hemminger1a620692006-10-12 14:45:38 -0700170void br_fdb_delete_by_port(struct net_bridge *br,
171 const struct net_bridge_port *p,
172 int do_all)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173{
174 int i;
175
176 spin_lock_bh(&br->hash_lock);
177 for (i = 0; i < BR_HASH_SIZE; i++) {
178 struct hlist_node *h, *g;
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900179
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 hlist_for_each_safe(h, g, &br->hash[i]) {
181 struct net_bridge_fdb_entry *f
182 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900183 if (f->dst != p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 continue;
185
Stephen Hemminger1a620692006-10-12 14:45:38 -0700186 if (f->is_static && !do_all)
187 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 /*
189 * if multiple ports all have the same device address
190 * then when one port is deleted, assign
191 * the local entry to other port
192 */
193 if (f->is_local) {
194 struct net_bridge_port *op;
195 list_for_each_entry(op, &br->port_list, list) {
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900196 if (op != p &&
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700197 !compare_ether_addr(op->dev->dev_addr,
198 f->addr.addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 f->dst = op;
200 goto skip_delete;
201 }
202 }
203 }
204
205 fdb_delete(f);
206 skip_delete: ;
207 }
208 }
209 spin_unlock_bh(&br->hash_lock);
210}
211
212/* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
213struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
214 const unsigned char *addr)
215{
216 struct hlist_node *h;
217 struct net_bridge_fdb_entry *fdb;
218
219 hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700220 if (!compare_ether_addr(fdb->addr.addr, addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 if (unlikely(has_expired(br, fdb)))
222 break;
223 return fdb;
224 }
225 }
226
227 return NULL;
228}
229
230/* Interface used by ATM hook that keeps a ref count */
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900231struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 unsigned char *addr)
233{
234 struct net_bridge_fdb_entry *fdb;
235
236 rcu_read_lock();
237 fdb = __br_fdb_get(br, addr);
Patrick McHardyb19cbe22007-03-22 12:25:20 -0700238 if (fdb && !atomic_inc_not_zero(&fdb->use_count))
239 fdb = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 rcu_read_unlock();
241 return fdb;
242}
243
244static void fdb_rcu_free(struct rcu_head *head)
245{
246 struct net_bridge_fdb_entry *ent
247 = container_of(head, struct net_bridge_fdb_entry, rcu);
248 kmem_cache_free(br_fdb_cache, ent);
249}
250
251/* Set entry up for deletion with RCU */
252void br_fdb_put(struct net_bridge_fdb_entry *ent)
253{
254 if (atomic_dec_and_test(&ent->use_count))
255 call_rcu(&ent->rcu, fdb_rcu_free);
256}
257
258/*
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900259 * Fill buffer with forwarding table records in
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 * the API format.
261 */
262int br_fdb_fillbuf(struct net_bridge *br, void *buf,
263 unsigned long maxnum, unsigned long skip)
264{
265 struct __fdb_entry *fe = buf;
266 int i, num = 0;
267 struct hlist_node *h;
268 struct net_bridge_fdb_entry *f;
269
270 memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
271
272 rcu_read_lock();
273 for (i = 0; i < BR_HASH_SIZE; i++) {
274 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
275 if (num >= maxnum)
276 goto out;
277
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900278 if (has_expired(br, f))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 continue;
280
281 if (skip) {
282 --skip;
283 continue;
284 }
285
286 /* convert from internal format to API */
287 memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
288 fe->port_no = f->dst->port_no;
289 fe->is_local = f->is_local;
290 if (!f->is_static)
291 fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
292 ++fe;
293 ++num;
294 }
295 }
296
297 out:
298 rcu_read_unlock();
299
300 return num;
301}
302
303static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
304 const unsigned char *addr)
305{
306 struct hlist_node *h;
307 struct net_bridge_fdb_entry *fdb;
308
309 hlist_for_each_entry_rcu(fdb, h, head, hlist) {
Stephen Hemminger6ede2462005-10-25 15:04:59 -0700310 if (!compare_ether_addr(fdb->addr.addr, addr))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 return fdb;
312 }
313 return NULL;
314}
315
316static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
317 struct net_bridge_port *source,
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900318 const unsigned char *addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 int is_local)
320{
321 struct net_bridge_fdb_entry *fdb;
322
323 fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
324 if (fdb) {
325 memcpy(fdb->addr.addr, addr, ETH_ALEN);
326 atomic_set(&fdb->use_count, 1);
327 hlist_add_head_rcu(&fdb->hlist, head);
328
329 fdb->dst = source;
330 fdb->is_local = is_local;
331 fdb->is_static = is_local;
332 fdb->ageing_timer = jiffies;
333 }
334 return fdb;
335}
336
337static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
338 const unsigned char *addr)
339{
340 struct hlist_head *head = &br->hash[br_mac_hash(addr)];
341 struct net_bridge_fdb_entry *fdb;
342
343 if (!is_valid_ether_addr(addr))
344 return -EINVAL;
345
346 fdb = fdb_find(head, addr);
347 if (fdb) {
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900348 /* it is okay to have multiple ports with same
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 * address, just use the first one.
350 */
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900351 if (fdb->is_local)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 return 0;
353
354 printk(KERN_WARNING "%s adding interface with same address "
355 "as a received packet\n",
356 source->dev->name);
357 fdb_delete(fdb);
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900358 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359
360 if (!fdb_create(head, source, addr, 1))
361 return -ENOMEM;
362
363 return 0;
364}
365
366int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
367 const unsigned char *addr)
368{
369 int ret;
370
371 spin_lock_bh(&br->hash_lock);
372 ret = fdb_insert(br, source, addr);
373 spin_unlock_bh(&br->hash_lock);
374 return ret;
375}
376
377void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
378 const unsigned char *addr)
379{
380 struct hlist_head *head = &br->hash[br_mac_hash(addr)];
381 struct net_bridge_fdb_entry *fdb;
382
383 /* some users want to always flood. */
384 if (hold_time(br) == 0)
385 return;
386
Stephen Hemmingerdf1c0b82007-08-30 22:15:35 -0700387 /* ignore packets unless we are using this port */
388 if (!(source->state == BR_STATE_LEARNING ||
389 source->state == BR_STATE_FORWARDING))
390 return;
391
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 fdb = fdb_find(head, addr);
393 if (likely(fdb)) {
394 /* attempt to update an entry for a local interface */
395 if (unlikely(fdb->is_local)) {
YOSHIFUJI Hideaki9d6f2292007-02-09 23:24:35 +0900396 if (net_ratelimit())
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 printk(KERN_WARNING "%s: received packet with "
398 " own address as source address\n",
399 source->dev->name);
400 } else {
401 /* fastpath: update of existing entry */
402 fdb->dst = source;
403 fdb->ageing_timer = jiffies;
404 }
405 } else {
Stephen Hemmingerf8ae7372006-03-20 22:58:36 -0800406 spin_lock(&br->hash_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 if (!fdb_find(head, addr))
408 fdb_create(head, source, addr, 0);
409 /* else we lose race and someone else inserts
410 * it first, don't bother updating
411 */
Stephen Hemmingerf8ae7372006-03-20 22:58:36 -0800412 spin_unlock(&br->hash_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414}