bridge: change console message interface
[linux-2.6.git] / net / bridge / br_fdb.c
1 /*
2  *      Forwarding database
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/kernel.h>
15 #include <linux/init.h>
16 #include <linux/rculist.h>
17 #include <linux/spinlock.h>
18 #include <linux/times.h>
19 #include <linux/netdevice.h>
20 #include <linux/etherdevice.h>
21 #include <linux/jhash.h>
22 #include <linux/random.h>
23 #include <linux/slab.h>
24 #include <asm/atomic.h>
25 #include <asm/unaligned.h>
26 #include "br_private.h"
27
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);
31
32 static u32 fdb_salt __read_mostly;
33
34 int __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);
40         if (!br_fdb_cache)
41                 return -ENOMEM;
42
43         get_random_bytes(&fdb_salt, sizeof(fdb_salt));
44         return 0;
45 }
46
47 void 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  */
56 static inline unsigned long hold_time(const struct net_bridge *br)
57 {
58         return br->topology_change ? br->forward_delay : br->ageing_time;
59 }
60
61 static inline int has_expired(const struct net_bridge *br,
62                                   const struct net_bridge_fdb_entry *fdb)
63 {
64         return !fdb->is_static &&
65                 time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
66 }
67
68 static inline int br_mac_hash(const unsigned char *mac)
69 {
70         /* 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);
73 }
74
75 static void fdb_rcu_free(struct rcu_head *head)
76 {
77         struct net_bridge_fdb_entry *ent
78                 = container_of(head, struct net_bridge_fdb_entry, rcu);
79         kmem_cache_free(br_fdb_cache, ent);
80 }
81
82 static inline void fdb_delete(struct net_bridge_fdb_entry *f)
83 {
84         hlist_del_rcu(&f->hlist);
85         call_rcu(&f->rcu, fdb_rcu_free);
86 }
87
88 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
89 {
90         struct net_bridge *br = p->br;
91         int i;
92
93         spin_lock_bh(&br->hash_lock);
94
95         /* Search all chains since old address/hash is unknown */
96         for (i = 0; i < BR_HASH_SIZE; i++) {
97                 struct hlist_node *h;
98                 hlist_for_each(h, &br->hash[i]) {
99                         struct net_bridge_fdb_entry *f;
100
101                         f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
102                         if (f->dst == p && f->is_local) {
103                                 /* maybe another port has same hw addr? */
104                                 struct net_bridge_port *op;
105                                 list_for_each_entry(op, &br->port_list, list) {
106                                         if (op != p &&
107                                             !compare_ether_addr(op->dev->dev_addr,
108                                                                 f->addr.addr)) {
109                                                 f->dst = op;
110                                                 goto insert;
111                                         }
112                                 }
113
114                                 /* delete old one */
115                                 fdb_delete(f);
116                                 goto insert;
117                         }
118                 }
119         }
120  insert:
121         /* insert new address,  may fail if invalid address or dup. */
122         fdb_insert(br, p, newaddr);
123
124         spin_unlock_bh(&br->hash_lock);
125 }
126
127 void br_fdb_cleanup(unsigned long _data)
128 {
129         struct net_bridge *br = (struct net_bridge *)_data;
130         unsigned long delay = hold_time(br);
131         unsigned long next_timer = jiffies + br->forward_delay;
132         int i;
133
134         spin_lock_bh(&br->hash_lock);
135         for (i = 0; i < BR_HASH_SIZE; i++) {
136                 struct net_bridge_fdb_entry *f;
137                 struct hlist_node *h, *n;
138
139                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
140                         unsigned long this_timer;
141                         if (f->is_static)
142                                 continue;
143                         this_timer = f->ageing_timer + delay;
144                         if (time_before_eq(this_timer, jiffies))
145                                 fdb_delete(f);
146                         else if (time_before(this_timer, next_timer))
147                                 next_timer = this_timer;
148                 }
149         }
150         spin_unlock_bh(&br->hash_lock);
151
152         /* Add HZ/4 to ensure we round the jiffies upwards to be after the next
153          * timer, otherwise we might round down and will have no-op run. */
154         mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
155 }
156
157 /* Completely flush all dynamic entries in forwarding database.*/
158 void br_fdb_flush(struct net_bridge *br)
159 {
160         int i;
161
162         spin_lock_bh(&br->hash_lock);
163         for (i = 0; i < BR_HASH_SIZE; i++) {
164                 struct net_bridge_fdb_entry *f;
165                 struct hlist_node *h, *n;
166                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
167                         if (!f->is_static)
168                                 fdb_delete(f);
169                 }
170         }
171         spin_unlock_bh(&br->hash_lock);
172 }
173
174 /* Flush all entries refering to a specific port.
175  * if do_all is set also flush static entries
176  */
177 void br_fdb_delete_by_port(struct net_bridge *br,
178                            const struct net_bridge_port *p,
179                            int do_all)
180 {
181         int i;
182
183         spin_lock_bh(&br->hash_lock);
184         for (i = 0; i < BR_HASH_SIZE; i++) {
185                 struct hlist_node *h, *g;
186
187                 hlist_for_each_safe(h, g, &br->hash[i]) {
188                         struct net_bridge_fdb_entry *f
189                                 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
190                         if (f->dst != p)
191                                 continue;
192
193                         if (f->is_static && !do_all)
194                                 continue;
195                         /*
196                          * if multiple ports all have the same device address
197                          * then when one port is deleted, assign
198                          * the local entry to other port
199                          */
200                         if (f->is_local) {
201                                 struct net_bridge_port *op;
202                                 list_for_each_entry(op, &br->port_list, list) {
203                                         if (op != p &&
204                                             !compare_ether_addr(op->dev->dev_addr,
205                                                                 f->addr.addr)) {
206                                                 f->dst = op;
207                                                 goto skip_delete;
208                                         }
209                                 }
210                         }
211
212                         fdb_delete(f);
213                 skip_delete: ;
214                 }
215         }
216         spin_unlock_bh(&br->hash_lock);
217 }
218
219 /* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
220 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
221                                           const unsigned char *addr)
222 {
223         struct hlist_node *h;
224         struct net_bridge_fdb_entry *fdb;
225
226         hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
227                 if (!compare_ether_addr(fdb->addr.addr, addr)) {
228                         if (unlikely(has_expired(br, fdb)))
229                                 break;
230                         return fdb;
231                 }
232         }
233
234         return NULL;
235 }
236
237 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
238 /* Interface used by ATM LANE hook to test
239  * if an addr is on some other bridge port */
240 int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
241 {
242         struct net_bridge_fdb_entry *fdb;
243         int ret;
244
245         if (!dev->br_port)
246                 return 0;
247
248         rcu_read_lock();
249         fdb = __br_fdb_get(dev->br_port->br, addr);
250         ret = fdb && fdb->dst->dev != dev &&
251                 fdb->dst->state == BR_STATE_FORWARDING;
252         rcu_read_unlock();
253
254         return ret;
255 }
256 #endif /* CONFIG_ATM_LANE */
257
258 /*
259  * Fill buffer with forwarding table records in
260  * the API format.
261  */
262 int 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
278                         if (has_expired(br, f))
279                                 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
289                         /* due to ABI compat need to split into hi/lo */
290                         fe->port_no = f->dst->port_no;
291                         fe->port_hi = f->dst->port_no >> 8;
292
293                         fe->is_local = f->is_local;
294                         if (!f->is_static)
295                                 fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
296                         ++fe;
297                         ++num;
298                 }
299         }
300
301  out:
302         rcu_read_unlock();
303
304         return num;
305 }
306
307 static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
308                                                     const unsigned char *addr)
309 {
310         struct hlist_node *h;
311         struct net_bridge_fdb_entry *fdb;
312
313         hlist_for_each_entry_rcu(fdb, h, head, hlist) {
314                 if (!compare_ether_addr(fdb->addr.addr, addr))
315                         return fdb;
316         }
317         return NULL;
318 }
319
320 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
321                                                struct net_bridge_port *source,
322                                                const unsigned char *addr,
323                                                int is_local)
324 {
325         struct net_bridge_fdb_entry *fdb;
326
327         fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
328         if (fdb) {
329                 memcpy(fdb->addr.addr, addr, ETH_ALEN);
330                 hlist_add_head_rcu(&fdb->hlist, head);
331
332                 fdb->dst = source;
333                 fdb->is_local = is_local;
334                 fdb->is_static = is_local;
335                 fdb->ageing_timer = jiffies;
336         }
337         return fdb;
338 }
339
340 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
341                   const unsigned char *addr)
342 {
343         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
344         struct net_bridge_fdb_entry *fdb;
345
346         if (!is_valid_ether_addr(addr))
347                 return -EINVAL;
348
349         fdb = fdb_find(head, addr);
350         if (fdb) {
351                 /* it is okay to have multiple ports with same
352                  * address, just use the first one.
353                  */
354                 if (fdb->is_local)
355                         return 0;
356                 br_warn(br, "adding interface %s with same address "
357                        "as a received packet\n",
358                        source->dev->name);
359                 fdb_delete(fdb);
360         }
361
362         if (!fdb_create(head, source, addr, 1))
363                 return -ENOMEM;
364
365         return 0;
366 }
367
368 int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
369                   const unsigned char *addr)
370 {
371         int ret;
372
373         spin_lock_bh(&br->hash_lock);
374         ret = fdb_insert(br, source, addr);
375         spin_unlock_bh(&br->hash_lock);
376         return ret;
377 }
378
379 void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
380                    const unsigned char *addr)
381 {
382         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
383         struct net_bridge_fdb_entry *fdb;
384
385         /* some users want to always flood. */
386         if (hold_time(br) == 0)
387                 return;
388
389         /* ignore packets unless we are using this port */
390         if (!(source->state == BR_STATE_LEARNING ||
391               source->state == BR_STATE_FORWARDING))
392                 return;
393
394         fdb = fdb_find(head, addr);
395         if (likely(fdb)) {
396                 /* attempt to update an entry for a local interface */
397                 if (unlikely(fdb->is_local)) {
398                         if (net_ratelimit())
399                                 br_warn(br, "received packet on %s with "
400                                         "own address as source address\n",
401                                         source->dev->name);
402                 } else {
403                         /* fastpath: update of existing entry */
404                         fdb->dst = source;
405                         fdb->ageing_timer = jiffies;
406                 }
407         } else {
408                 spin_lock(&br->hash_lock);
409                 if (!fdb_find(head, addr))
410                         fdb_create(head, source, addr, 0);
411                 /* else  we lose race and someone else inserts
412                  * it first, don't bother updating
413                  */
414                 spin_unlock(&br->hash_lock);
415         }
416 }