3 * Linux ethernet bridge
6 * Lennert Buytenhek <buytenh@gnu.org>
8 * $Id: br_fdb.c,v 1.6 2002/01/17 00:57:07 davem Exp $
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.
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 <linux/random.h>
24 #include <asm/atomic.h>
25 #include <asm/unaligned.h>
26 #include "br_private.h"
28 static struct kmem_cache
*br_fdb_cache __read_mostly
;
29 static int fdb_insert(struct net_bridge
*br
, struct net_bridge_port
*source
,
30 const unsigned char *addr
);
32 static u32 fdb_salt __read_mostly
;
34 void __init
br_fdb_init(void)
36 br_fdb_cache
= kmem_cache_create("bridge_fdb_cache",
37 sizeof(struct net_bridge_fdb_entry
),
39 SLAB_HWCACHE_ALIGN
, NULL
, NULL
);
40 get_random_bytes(&fdb_salt
, sizeof(fdb_salt
));
43 void __exit
br_fdb_fini(void)
45 kmem_cache_destroy(br_fdb_cache
);
49 /* if topology_changing then use forward_delay (default 15 sec)
50 * otherwise keep longer (default 5 minutes)
52 static inline unsigned long hold_time(const struct net_bridge
*br
)
54 return br
->topology_change
? br
->forward_delay
: br
->ageing_time
;
57 static inline int has_expired(const struct net_bridge
*br
,
58 const struct net_bridge_fdb_entry
*fdb
)
60 return !fdb
->is_static
61 && time_before_eq(fdb
->ageing_timer
+ hold_time(br
), jiffies
);
64 static inline int br_mac_hash(const unsigned char *mac
)
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);
71 static inline void fdb_delete(struct net_bridge_fdb_entry
*f
)
73 hlist_del_rcu(&f
->hlist
);
77 void br_fdb_changeaddr(struct net_bridge_port
*p
, const unsigned char *newaddr
)
79 struct net_bridge
*br
= p
->br
;
82 spin_lock_bh(&br
->hash_lock
);
84 /* Search all chains since old address/hash is unknown */
85 for (i
= 0; i
< BR_HASH_SIZE
; i
++) {
87 hlist_for_each(h
, &br
->hash
[i
]) {
88 struct net_bridge_fdb_entry
*f
;
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
) {
96 !compare_ether_addr(op
->dev
->dev_addr
,
110 /* insert new address, may fail if invalid address or dup. */
111 fdb_insert(br
, p
, newaddr
);
113 spin_unlock_bh(&br
->hash_lock
);
116 void br_fdb_cleanup(unsigned long _data
)
118 struct net_bridge
*br
= (struct net_bridge
*)_data
;
119 unsigned long delay
= hold_time(br
);
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
;
127 hlist_for_each_entry_safe(f
, h
, n
, &br
->hash
[i
], hlist
) {
129 time_before_eq(f
->ageing_timer
+ delay
, jiffies
))
133 spin_unlock_bh(&br
->hash_lock
);
135 mod_timer(&br
->gc_timer
, jiffies
+ HZ
/10);
139 void br_fdb_delete_by_port(struct net_bridge
*br
,
140 const struct net_bridge_port
*p
,
145 spin_lock_bh(&br
->hash_lock
);
146 for (i
= 0; i
< BR_HASH_SIZE
; i
++) {
147 struct hlist_node
*h
, *g
;
149 hlist_for_each_safe(h
, g
, &br
->hash
[i
]) {
150 struct net_bridge_fdb_entry
*f
151 = hlist_entry(h
, struct net_bridge_fdb_entry
, hlist
);
155 if (f
->is_static
&& !do_all
)
158 * if multiple ports all have the same device address
159 * then when one port is deleted, assign
160 * the local entry to other port
163 struct net_bridge_port
*op
;
164 list_for_each_entry(op
, &br
->port_list
, list
) {
166 !compare_ether_addr(op
->dev
->dev_addr
,
178 spin_unlock_bh(&br
->hash_lock
);
181 /* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
182 struct net_bridge_fdb_entry
*__br_fdb_get(struct net_bridge
*br
,
183 const unsigned char *addr
)
185 struct hlist_node
*h
;
186 struct net_bridge_fdb_entry
*fdb
;
188 hlist_for_each_entry_rcu(fdb
, h
, &br
->hash
[br_mac_hash(addr
)], hlist
) {
189 if (!compare_ether_addr(fdb
->addr
.addr
, addr
)) {
190 if (unlikely(has_expired(br
, fdb
)))
199 /* Interface used by ATM hook that keeps a ref count */
200 struct net_bridge_fdb_entry
*br_fdb_get(struct net_bridge
*br
,
203 struct net_bridge_fdb_entry
*fdb
;
206 fdb
= __br_fdb_get(br
, addr
);
207 if (fdb
&& !atomic_inc_not_zero(&fdb
->use_count
))
213 static void fdb_rcu_free(struct rcu_head
*head
)
215 struct net_bridge_fdb_entry
*ent
216 = container_of(head
, struct net_bridge_fdb_entry
, rcu
);
217 kmem_cache_free(br_fdb_cache
, ent
);
220 /* Set entry up for deletion with RCU */
221 void br_fdb_put(struct net_bridge_fdb_entry
*ent
)
223 if (atomic_dec_and_test(&ent
->use_count
))
224 call_rcu(&ent
->rcu
, fdb_rcu_free
);
228 * Fill buffer with forwarding table records in
231 int br_fdb_fillbuf(struct net_bridge
*br
, void *buf
,
232 unsigned long maxnum
, unsigned long skip
)
234 struct __fdb_entry
*fe
= buf
;
236 struct hlist_node
*h
;
237 struct net_bridge_fdb_entry
*f
;
239 memset(buf
, 0, maxnum
*sizeof(struct __fdb_entry
));
242 for (i
= 0; i
< BR_HASH_SIZE
; i
++) {
243 hlist_for_each_entry_rcu(f
, h
, &br
->hash
[i
], hlist
) {
247 if (has_expired(br
, f
))
255 /* convert from internal format to API */
256 memcpy(fe
->mac_addr
, f
->addr
.addr
, ETH_ALEN
);
257 fe
->port_no
= f
->dst
->port_no
;
258 fe
->is_local
= f
->is_local
;
260 fe
->ageing_timer_value
= jiffies_to_clock_t(jiffies
- f
->ageing_timer
);
272 static inline struct net_bridge_fdb_entry
*fdb_find(struct hlist_head
*head
,
273 const unsigned char *addr
)
275 struct hlist_node
*h
;
276 struct net_bridge_fdb_entry
*fdb
;
278 hlist_for_each_entry_rcu(fdb
, h
, head
, hlist
) {
279 if (!compare_ether_addr(fdb
->addr
.addr
, addr
))
285 static struct net_bridge_fdb_entry
*fdb_create(struct hlist_head
*head
,
286 struct net_bridge_port
*source
,
287 const unsigned char *addr
,
290 struct net_bridge_fdb_entry
*fdb
;
292 fdb
= kmem_cache_alloc(br_fdb_cache
, GFP_ATOMIC
);
294 memcpy(fdb
->addr
.addr
, addr
, ETH_ALEN
);
295 atomic_set(&fdb
->use_count
, 1);
296 hlist_add_head_rcu(&fdb
->hlist
, head
);
299 fdb
->is_local
= is_local
;
300 fdb
->is_static
= is_local
;
301 fdb
->ageing_timer
= jiffies
;
306 static int fdb_insert(struct net_bridge
*br
, struct net_bridge_port
*source
,
307 const unsigned char *addr
)
309 struct hlist_head
*head
= &br
->hash
[br_mac_hash(addr
)];
310 struct net_bridge_fdb_entry
*fdb
;
312 if (!is_valid_ether_addr(addr
))
315 fdb
= fdb_find(head
, addr
);
317 /* it is okay to have multiple ports with same
318 * address, just use the first one.
323 printk(KERN_WARNING
"%s adding interface with same address "
324 "as a received packet\n",
329 if (!fdb_create(head
, source
, addr
, 1))
335 int br_fdb_insert(struct net_bridge
*br
, struct net_bridge_port
*source
,
336 const unsigned char *addr
)
340 spin_lock_bh(&br
->hash_lock
);
341 ret
= fdb_insert(br
, source
, addr
);
342 spin_unlock_bh(&br
->hash_lock
);
346 void br_fdb_update(struct net_bridge
*br
, struct net_bridge_port
*source
,
347 const unsigned char *addr
)
349 struct hlist_head
*head
= &br
->hash
[br_mac_hash(addr
)];
350 struct net_bridge_fdb_entry
*fdb
;
352 /* some users want to always flood. */
353 if (hold_time(br
) == 0)
356 fdb
= fdb_find(head
, addr
);
358 /* attempt to update an entry for a local interface */
359 if (unlikely(fdb
->is_local
)) {
361 printk(KERN_WARNING
"%s: received packet with "
362 " own address as source address\n",
365 /* fastpath: update of existing entry */
367 fdb
->ageing_timer
= jiffies
;
370 spin_lock(&br
->hash_lock
);
371 if (!fdb_find(head
, addr
))
372 fdb_create(head
, source
, addr
, 0);
373 /* else we lose race and someone else inserts
374 * it first, don't bother updating
376 spin_unlock(&br
->hash_lock
);