Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6] / 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 <asm/atomic.h>
24 #include <asm/unaligned.h>
25 #include "br_private.h"
26
27 static struct kmem_cache *br_fdb_cache __read_mostly;
28 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
29                       const unsigned char *addr);
30
31 static u32 fdb_salt __read_mostly;
32
33 int __init br_fdb_init(void)
34 {
35         br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
36                                          sizeof(struct net_bridge_fdb_entry),
37                                          0,
38                                          SLAB_HWCACHE_ALIGN, NULL);
39         if (!br_fdb_cache)
40                 return -ENOMEM;
41
42         get_random_bytes(&fdb_salt, sizeof(fdb_salt));
43         return 0;
44 }
45
46 void br_fdb_fini(void)
47 {
48         kmem_cache_destroy(br_fdb_cache);
49 }
50
51
52 /* if topology_changing then use forward_delay (default 15 sec)
53  * otherwise keep longer (default 5 minutes)
54  */
55 static inline unsigned long hold_time(const struct net_bridge *br)
56 {
57         return br->topology_change ? br->forward_delay : br->ageing_time;
58 }
59
60 static inline int has_expired(const struct net_bridge *br,
61                                   const struct net_bridge_fdb_entry *fdb)
62 {
63         return !fdb->is_static
64                 && time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
65 }
66
67 static inline int br_mac_hash(const unsigned char *mac)
68 {
69         /* use 1 byte of OUI cnd 3 bytes of NIC */
70         u32 key = get_unaligned((u32 *)(mac + 2));
71         return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
72 }
73
74 static inline void fdb_delete(struct net_bridge_fdb_entry *f)
75 {
76         hlist_del_rcu(&f->hlist);
77         br_fdb_put(f);
78 }
79
80 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
81 {
82         struct net_bridge *br = p->br;
83         int i;
84
85         spin_lock_bh(&br->hash_lock);
86
87         /* Search all chains since old address/hash is unknown */
88         for (i = 0; i < BR_HASH_SIZE; i++) {
89                 struct hlist_node *h;
90                 hlist_for_each(h, &br->hash[i]) {
91                         struct net_bridge_fdb_entry *f;
92
93                         f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
94                         if (f->dst == p && f->is_local) {
95                                 /* maybe another port has same hw addr? */
96                                 struct net_bridge_port *op;
97                                 list_for_each_entry(op, &br->port_list, list) {
98                                         if (op != p &&
99                                             !compare_ether_addr(op->dev->dev_addr,
100                                                                 f->addr.addr)) {
101                                                 f->dst = op;
102                                                 goto insert;
103                                         }
104                                 }
105
106                                 /* delete old one */
107                                 fdb_delete(f);
108                                 goto insert;
109                         }
110                 }
111         }
112  insert:
113         /* insert new address,  may fail if invalid address or dup. */
114         fdb_insert(br, p, newaddr);
115
116         spin_unlock_bh(&br->hash_lock);
117 }
118
119 void br_fdb_cleanup(unsigned long _data)
120 {
121         struct net_bridge *br = (struct net_bridge *)_data;
122         unsigned long delay = hold_time(br);
123         unsigned long next_timer = jiffies + br->forward_delay;
124         int i;
125
126         spin_lock_bh(&br->hash_lock);
127         for (i = 0; i < BR_HASH_SIZE; i++) {
128                 struct net_bridge_fdb_entry *f;
129                 struct hlist_node *h, *n;
130
131                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
132                         unsigned long this_timer;
133                         if (f->is_static)
134                                 continue;
135                         this_timer = f->ageing_timer + delay;
136                         if (time_before_eq(this_timer, jiffies))
137                                 fdb_delete(f);
138                         else if (time_before(this_timer, next_timer))
139                                 next_timer = this_timer;
140                 }
141         }
142         spin_unlock_bh(&br->hash_lock);
143
144         /* Add HZ/4 to ensure we round the jiffies upwards to be after the next
145          * timer, otherwise we might round down and will have no-op run. */
146         mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
147 }
148
149 /* Completely flush all dynamic entries in forwarding database.*/
150 void br_fdb_flush(struct net_bridge *br)
151 {
152         int i;
153
154         spin_lock_bh(&br->hash_lock);
155         for (i = 0; i < BR_HASH_SIZE; i++) {
156                 struct net_bridge_fdb_entry *f;
157                 struct hlist_node *h, *n;
158                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
159                         if (!f->is_static)
160                                 fdb_delete(f);
161                 }
162         }
163         spin_unlock_bh(&br->hash_lock);
164 }
165
166 /* Flush all entries refering to a specific port.
167  * if do_all is set also flush static entries
168  */
169 void br_fdb_delete_by_port(struct net_bridge *br,
170                            const struct net_bridge_port *p,
171                            int do_all)
172 {
173         int i;
174
175         spin_lock_bh(&br->hash_lock);
176         for (i = 0; i < BR_HASH_SIZE; i++) {
177                 struct hlist_node *h, *g;
178
179                 hlist_for_each_safe(h, g, &br->hash[i]) {
180                         struct net_bridge_fdb_entry *f
181                                 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
182                         if (f->dst != p)
183                                 continue;
184
185                         if (f->is_static && !do_all)
186                                 continue;
187                         /*
188                          * if multiple ports all have the same device address
189                          * then when one port is deleted, assign
190                          * the local entry to other port
191                          */
192                         if (f->is_local) {
193                                 struct net_bridge_port *op;
194                                 list_for_each_entry(op, &br->port_list, list) {
195                                         if (op != p &&
196                                             !compare_ether_addr(op->dev->dev_addr,
197                                                                 f->addr.addr)) {
198                                                 f->dst = op;
199                                                 goto skip_delete;
200                                         }
201                                 }
202                         }
203
204                         fdb_delete(f);
205                 skip_delete: ;
206                 }
207         }
208         spin_unlock_bh(&br->hash_lock);
209 }
210
211 /* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
212 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
213                                           const unsigned char *addr)
214 {
215         struct hlist_node *h;
216         struct net_bridge_fdb_entry *fdb;
217
218         hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
219                 if (!compare_ether_addr(fdb->addr.addr, addr)) {
220                         if (unlikely(has_expired(br, fdb)))
221                                 break;
222                         return fdb;
223                 }
224         }
225
226         return NULL;
227 }
228
229 /* Interface used by ATM hook that keeps a ref count */
230 struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
231                                         unsigned char *addr)
232 {
233         struct net_bridge_fdb_entry *fdb;
234
235         rcu_read_lock();
236         fdb = __br_fdb_get(br, addr);
237         if (fdb && !atomic_inc_not_zero(&fdb->use_count))
238                 fdb = NULL;
239         rcu_read_unlock();
240         return fdb;
241 }
242
243 static void fdb_rcu_free(struct rcu_head *head)
244 {
245         struct net_bridge_fdb_entry *ent
246                 = container_of(head, struct net_bridge_fdb_entry, rcu);
247         kmem_cache_free(br_fdb_cache, ent);
248 }
249
250 /* Set entry up for deletion with RCU  */
251 void br_fdb_put(struct net_bridge_fdb_entry *ent)
252 {
253         if (atomic_dec_and_test(&ent->use_count))
254                 call_rcu(&ent->rcu, fdb_rcu_free);
255 }
256
257 /*
258  * Fill buffer with forwarding table records in
259  * the API format.
260  */
261 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
262                    unsigned long maxnum, unsigned long skip)
263 {
264         struct __fdb_entry *fe = buf;
265         int i, num = 0;
266         struct hlist_node *h;
267         struct net_bridge_fdb_entry *f;
268
269         memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
270
271         rcu_read_lock();
272         for (i = 0; i < BR_HASH_SIZE; i++) {
273                 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
274                         if (num >= maxnum)
275                                 goto out;
276
277                         if (has_expired(br, f))
278                                 continue;
279
280                         if (skip) {
281                                 --skip;
282                                 continue;
283                         }
284
285                         /* convert from internal format to API */
286                         memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
287
288                         /* due to ABI compat need to split into hi/lo */
289                         fe->port_no = f->dst->port_no;
290                         fe->port_hi = f->dst->port_no >> 8;
291
292                         fe->is_local = f->is_local;
293                         if (!f->is_static)
294                                 fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
295                         ++fe;
296                         ++num;
297                 }
298         }
299
300  out:
301         rcu_read_unlock();
302
303         return num;
304 }
305
306 static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
307                                                     const unsigned char *addr)
308 {
309         struct hlist_node *h;
310         struct net_bridge_fdb_entry *fdb;
311
312         hlist_for_each_entry_rcu(fdb, h, head, hlist) {
313                 if (!compare_ether_addr(fdb->addr.addr, addr))
314                         return fdb;
315         }
316         return NULL;
317 }
318
319 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
320                                                struct net_bridge_port *source,
321                                                const unsigned char *addr,
322                                                int is_local)
323 {
324         struct net_bridge_fdb_entry *fdb;
325
326         fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
327         if (fdb) {
328                 memcpy(fdb->addr.addr, addr, ETH_ALEN);
329                 atomic_set(&fdb->use_count, 1);
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
357                 printk(KERN_WARNING "%s adding interface with same address "
358                        "as a received packet\n",
359                        source->dev->name);
360                 fdb_delete(fdb);
361         }
362
363         if (!fdb_create(head, source, addr, 1))
364                 return -ENOMEM;
365
366         return 0;
367 }
368
369 int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
370                   const unsigned char *addr)
371 {
372         int ret;
373
374         spin_lock_bh(&br->hash_lock);
375         ret = fdb_insert(br, source, addr);
376         spin_unlock_bh(&br->hash_lock);
377         return ret;
378 }
379
380 void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
381                    const unsigned char *addr)
382 {
383         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
384         struct net_bridge_fdb_entry *fdb;
385
386         /* some users want to always flood. */
387         if (hold_time(br) == 0)
388                 return;
389
390         /* ignore packets unless we are using this port */
391         if (!(source->state == BR_STATE_LEARNING ||
392               source->state == BR_STATE_FORWARDING))
393                 return;
394
395         fdb = fdb_find(head, addr);
396         if (likely(fdb)) {
397                 /* attempt to update an entry for a local interface */
398                 if (unlikely(fdb->is_local)) {
399                         if (net_ratelimit())
400                                 printk(KERN_WARNING "%s: received packet with "
401                                        " own address as source address\n",
402                                        source->dev->name);
403                 } else {
404                         /* fastpath: update of existing entry */
405                         fdb->dst = source;
406                         fdb->ageing_timer = jiffies;
407                 }
408         } else {
409                 spin_lock(&br->hash_lock);
410                 if (!fdb_find(head, addr))
411                         fdb_create(head, source, addr, 0);
412                 /* else  we lose race and someone else inserts
413                  * it first, don't bother updating
414                  */
415                 spin_unlock(&br->hash_lock);
416         }
417 }