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Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
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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/spinlock.h>
17 #include <linux/times.h>
18 #include <linux/netdevice.h>
19 #include <linux/etherdevice.h>
20 #include <linux/jhash.h>
21 #include <linux/random.h>
22 #include <asm/atomic.h>
23 #include <asm/unaligned.h>
24 #include "br_private.h"
25
26 static struct kmem_cache *br_fdb_cache __read_mostly;
27 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
28                       const unsigned char *addr);
29
30 static u32 fdb_salt __read_mostly;
31
32 int __init br_fdb_init(void)
33 {
34         br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
35                                          sizeof(struct net_bridge_fdb_entry),
36                                          0,
37                                          SLAB_HWCACHE_ALIGN, NULL);
38         if (!br_fdb_cache)
39                 return -ENOMEM;
40
41         get_random_bytes(&fdb_salt, sizeof(fdb_salt));
42         return 0;
43 }
44
45 void br_fdb_fini(void)
46 {
47         kmem_cache_destroy(br_fdb_cache);
48 }
49
50
51 /* if topology_changing then use forward_delay (default 15 sec)
52  * otherwise keep longer (default 5 minutes)
53  */
54 static inline unsigned long hold_time(const struct net_bridge *br)
55 {
56         return br->topology_change ? br->forward_delay : br->ageing_time;
57 }
58
59 static inline int has_expired(const struct net_bridge *br,
60                                   const struct net_bridge_fdb_entry *fdb)
61 {
62         return !fdb->is_static
63                 && time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
64 }
65
66 static inline int br_mac_hash(const unsigned char *mac)
67 {
68         /* use 1 byte of OUI cnd 3 bytes of NIC */
69         u32 key = get_unaligned((u32 *)(mac + 2));
70         return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
71 }
72
73 static inline void fdb_delete(struct net_bridge_fdb_entry *f)
74 {
75         hlist_del_rcu(&f->hlist);
76         br_fdb_put(f);
77 }
78
79 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
80 {
81         struct net_bridge *br = p->br;
82         int i;
83
84         spin_lock_bh(&br->hash_lock);
85
86         /* Search all chains since old address/hash is unknown */
87         for (i = 0; i < BR_HASH_SIZE; i++) {
88                 struct hlist_node *h;
89                 hlist_for_each(h, &br->hash[i]) {
90                         struct net_bridge_fdb_entry *f;
91
92                         f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
93                         if (f->dst == p && f->is_local) {
94                                 /* maybe another port has same hw addr? */
95                                 struct net_bridge_port *op;
96                                 list_for_each_entry(op, &br->port_list, list) {
97                                         if (op != p &&
98                                             !compare_ether_addr(op->dev->dev_addr,
99                                                                 f->addr.addr)) {
100                                                 f->dst = op;
101                                                 goto insert;
102                                         }
103                                 }
104
105                                 /* delete old one */
106                                 fdb_delete(f);
107                                 goto insert;
108                         }
109                 }
110         }
111  insert:
112         /* insert new address,  may fail if invalid address or dup. */
113         fdb_insert(br, p, newaddr);
114
115         spin_unlock_bh(&br->hash_lock);
116 }
117
118 void br_fdb_cleanup(unsigned long _data)
119 {
120         struct net_bridge *br = (struct net_bridge *)_data;
121         unsigned long delay = hold_time(br);
122         unsigned long next_timer = jiffies + br->forward_delay;
123         int i;
124
125         spin_lock_bh(&br->hash_lock);
126         for (i = 0; i < BR_HASH_SIZE; i++) {
127                 struct net_bridge_fdb_entry *f;
128                 struct hlist_node *h, *n;
129
130                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
131                         unsigned long this_timer;
132                         if (f->is_static)
133                                 continue;
134                         this_timer = f->ageing_timer + delay;
135                         if (time_before_eq(this_timer, jiffies))
136                                 fdb_delete(f);
137                         else if (time_before(this_timer, next_timer))
138                                 next_timer = this_timer;
139                 }
140         }
141         spin_unlock_bh(&br->hash_lock);
142
143         /* Add HZ/4 to ensure we round the jiffies upwards to be after the next
144          * timer, otherwise we might round down and will have no-op run. */
145         mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
146 }
147
148 /* Completely flush all dynamic entries in forwarding database.*/
149 void br_fdb_flush(struct net_bridge *br)
150 {
151         int i;
152
153         spin_lock_bh(&br->hash_lock);
154         for (i = 0; i < BR_HASH_SIZE; i++) {
155                 struct net_bridge_fdb_entry *f;
156                 struct hlist_node *h, *n;
157                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
158                         if (!f->is_static)
159                                 fdb_delete(f);
160                 }
161         }
162         spin_unlock_bh(&br->hash_lock);
163 }
164
165 /* Flush all entries refering to a specific port.
166  * if do_all is set also flush static entries
167  */
168 void br_fdb_delete_by_port(struct net_bridge *br,
169                            const struct net_bridge_port *p,
170                            int do_all)
171 {
172         int i;
173
174         spin_lock_bh(&br->hash_lock);
175         for (i = 0; i < BR_HASH_SIZE; i++) {
176                 struct hlist_node *h, *g;
177
178                 hlist_for_each_safe(h, g, &br->hash[i]) {
179                         struct net_bridge_fdb_entry *f
180                                 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
181                         if (f->dst != p)
182                                 continue;
183
184                         if (f->is_static && !do_all)
185                                 continue;
186                         /*
187                          * if multiple ports all have the same device address
188                          * then when one port is deleted, assign
189                          * the local entry to other port
190                          */
191                         if (f->is_local) {
192                                 struct net_bridge_port *op;
193                                 list_for_each_entry(op, &br->port_list, list) {
194                                         if (op != p &&
195                                             !compare_ether_addr(op->dev->dev_addr,
196                                                                 f->addr.addr)) {
197                                                 f->dst = op;
198                                                 goto skip_delete;
199                                         }
200                                 }
201                         }
202
203                         fdb_delete(f);
204                 skip_delete: ;
205                 }
206         }
207         spin_unlock_bh(&br->hash_lock);
208 }
209
210 /* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
211 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
212                                           const unsigned char *addr)
213 {
214         struct hlist_node *h;
215         struct net_bridge_fdb_entry *fdb;
216
217         hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
218                 if (!compare_ether_addr(fdb->addr.addr, addr)) {
219                         if (unlikely(has_expired(br, fdb)))
220                                 break;
221                         return fdb;
222                 }
223         }
224
225         return NULL;
226 }
227
228 /* Interface used by ATM hook that keeps a ref count */
229 struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
230                                         unsigned char *addr)
231 {
232         struct net_bridge_fdb_entry *fdb;
233
234         rcu_read_lock();
235         fdb = __br_fdb_get(br, addr);
236         if (fdb && !atomic_inc_not_zero(&fdb->use_count))
237                 fdb = NULL;
238         rcu_read_unlock();
239         return fdb;
240 }
241
242 static void fdb_rcu_free(struct rcu_head *head)
243 {
244         struct net_bridge_fdb_entry *ent
245                 = container_of(head, struct net_bridge_fdb_entry, rcu);
246         kmem_cache_free(br_fdb_cache, ent);
247 }
248
249 /* Set entry up for deletion with RCU  */
250 void br_fdb_put(struct net_bridge_fdb_entry *ent)
251 {
252         if (atomic_dec_and_test(&ent->use_count))
253                 call_rcu(&ent->rcu, fdb_rcu_free);
254 }
255
256 /*
257  * Fill buffer with forwarding table records in
258  * the API format.
259  */
260 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
261                    unsigned long maxnum, unsigned long skip)
262 {
263         struct __fdb_entry *fe = buf;
264         int i, num = 0;
265         struct hlist_node *h;
266         struct net_bridge_fdb_entry *f;
267
268         memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
269
270         rcu_read_lock();
271         for (i = 0; i < BR_HASH_SIZE; i++) {
272                 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
273                         if (num >= maxnum)
274                                 goto out;
275
276                         if (has_expired(br, f))
277                                 continue;
278
279                         if (skip) {
280                                 --skip;
281                                 continue;
282                         }
283
284                         /* convert from internal format to API */
285                         memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
286
287                         /* due to ABI compat need to split into hi/lo */
288                         fe->port_no = f->dst->port_no;
289                         fe->port_hi = f->dst->port_no >> 8;
290
291                         fe->is_local = f->is_local;
292                         if (!f->is_static)
293                                 fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
294                         ++fe;
295                         ++num;
296                 }
297         }
298
299  out:
300         rcu_read_unlock();
301
302         return num;
303 }
304
305 static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
306                                                     const unsigned char *addr)
307 {
308         struct hlist_node *h;
309         struct net_bridge_fdb_entry *fdb;
310
311         hlist_for_each_entry_rcu(fdb, h, head, hlist) {
312                 if (!compare_ether_addr(fdb->addr.addr, addr))
313                         return fdb;
314         }
315         return NULL;
316 }
317
318 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
319                                                struct net_bridge_port *source,
320                                                const unsigned char *addr,
321                                                int is_local)
322 {
323         struct net_bridge_fdb_entry *fdb;
324
325         fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
326         if (fdb) {
327                 memcpy(fdb->addr.addr, addr, ETH_ALEN);
328                 atomic_set(&fdb->use_count, 1);
329                 hlist_add_head_rcu(&fdb->hlist, head);
330
331                 fdb->dst = source;
332                 fdb->is_local = is_local;
333                 fdb->is_static = is_local;
334                 fdb->ageing_timer = jiffies;
335         }
336         return fdb;
337 }
338
339 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
340                   const unsigned char *addr)
341 {
342         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
343         struct net_bridge_fdb_entry *fdb;
344
345         if (!is_valid_ether_addr(addr))
346                 return -EINVAL;
347
348         fdb = fdb_find(head, addr);
349         if (fdb) {
350                 /* it is okay to have multiple ports with same
351                  * address, just use the first one.
352                  */
353                 if (fdb->is_local)
354                         return 0;
355
356                 printk(KERN_WARNING "%s adding interface 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                                 printk(KERN_WARNING "%s: received packet 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 }