net: Move && and || to end of previous line
[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 <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 void fdb_rcu_free(struct rcu_head *head)
75 {
76         struct net_bridge_fdb_entry *ent
77                 = container_of(head, struct net_bridge_fdb_entry, rcu);
78         kmem_cache_free(br_fdb_cache, ent);
79 }
80
81 static inline void fdb_delete(struct net_bridge_fdb_entry *f)
82 {
83         hlist_del_rcu(&f->hlist);
84         call_rcu(&f->rcu, fdb_rcu_free);
85 }
86
87 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
88 {
89         struct net_bridge *br = p->br;
90         int i;
91
92         spin_lock_bh(&br->hash_lock);
93
94         /* Search all chains since old address/hash is unknown */
95         for (i = 0; i < BR_HASH_SIZE; i++) {
96                 struct hlist_node *h;
97                 hlist_for_each(h, &br->hash[i]) {
98                         struct net_bridge_fdb_entry *f;
99
100                         f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
101                         if (f->dst == p && f->is_local) {
102                                 /* maybe another port has same hw addr? */
103                                 struct net_bridge_port *op;
104                                 list_for_each_entry(op, &br->port_list, list) {
105                                         if (op != p &&
106                                             !compare_ether_addr(op->dev->dev_addr,
107                                                                 f->addr.addr)) {
108                                                 f->dst = op;
109                                                 goto insert;
110                                         }
111                                 }
112
113                                 /* delete old one */
114                                 fdb_delete(f);
115                                 goto insert;
116                         }
117                 }
118         }
119  insert:
120         /* insert new address,  may fail if invalid address or dup. */
121         fdb_insert(br, p, newaddr);
122
123         spin_unlock_bh(&br->hash_lock);
124 }
125
126 void br_fdb_cleanup(unsigned long _data)
127 {
128         struct net_bridge *br = (struct net_bridge *)_data;
129         unsigned long delay = hold_time(br);
130         unsigned long next_timer = jiffies + br->forward_delay;
131         int i;
132
133         spin_lock_bh(&br->hash_lock);
134         for (i = 0; i < BR_HASH_SIZE; i++) {
135                 struct net_bridge_fdb_entry *f;
136                 struct hlist_node *h, *n;
137
138                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
139                         unsigned long this_timer;
140                         if (f->is_static)
141                                 continue;
142                         this_timer = f->ageing_timer + delay;
143                         if (time_before_eq(this_timer, jiffies))
144                                 fdb_delete(f);
145                         else if (time_before(this_timer, next_timer))
146                                 next_timer = this_timer;
147                 }
148         }
149         spin_unlock_bh(&br->hash_lock);
150
151         /* Add HZ/4 to ensure we round the jiffies upwards to be after the next
152          * timer, otherwise we might round down and will have no-op run. */
153         mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
154 }
155
156 /* Completely flush all dynamic entries in forwarding database.*/
157 void br_fdb_flush(struct net_bridge *br)
158 {
159         int i;
160
161         spin_lock_bh(&br->hash_lock);
162         for (i = 0; i < BR_HASH_SIZE; i++) {
163                 struct net_bridge_fdb_entry *f;
164                 struct hlist_node *h, *n;
165                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
166                         if (!f->is_static)
167                                 fdb_delete(f);
168                 }
169         }
170         spin_unlock_bh(&br->hash_lock);
171 }
172
173 /* Flush all entries refering to a specific port.
174  * if do_all is set also flush static entries
175  */
176 void br_fdb_delete_by_port(struct net_bridge *br,
177                            const struct net_bridge_port *p,
178                            int do_all)
179 {
180         int i;
181
182         spin_lock_bh(&br->hash_lock);
183         for (i = 0; i < BR_HASH_SIZE; i++) {
184                 struct hlist_node *h, *g;
185
186                 hlist_for_each_safe(h, g, &br->hash[i]) {
187                         struct net_bridge_fdb_entry *f
188                                 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
189                         if (f->dst != p)
190                                 continue;
191
192                         if (f->is_static && !do_all)
193                                 continue;
194                         /*
195                          * if multiple ports all have the same device address
196                          * then when one port is deleted, assign
197                          * the local entry to other port
198                          */
199                         if (f->is_local) {
200                                 struct net_bridge_port *op;
201                                 list_for_each_entry(op, &br->port_list, list) {
202                                         if (op != p &&
203                                             !compare_ether_addr(op->dev->dev_addr,
204                                                                 f->addr.addr)) {
205                                                 f->dst = op;
206                                                 goto skip_delete;
207                                         }
208                                 }
209                         }
210
211                         fdb_delete(f);
212                 skip_delete: ;
213                 }
214         }
215         spin_unlock_bh(&br->hash_lock);
216 }
217
218 /* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
219 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
220                                           const unsigned char *addr)
221 {
222         struct hlist_node *h;
223         struct net_bridge_fdb_entry *fdb;
224
225         hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
226                 if (!compare_ether_addr(fdb->addr.addr, addr)) {
227                         if (unlikely(has_expired(br, fdb)))
228                                 break;
229                         return fdb;
230                 }
231         }
232
233         return NULL;
234 }
235
236 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
237 /* Interface used by ATM LANE hook to test
238  * if an addr is on some other bridge port */
239 int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
240 {
241         struct net_bridge_fdb_entry *fdb;
242         int ret;
243
244         if (!dev->br_port)
245                 return 0;
246
247         rcu_read_lock();
248         fdb = __br_fdb_get(dev->br_port->br, addr);
249         ret = fdb && fdb->dst->dev != dev &&
250                 fdb->dst->state == BR_STATE_FORWARDING;
251         rcu_read_unlock();
252
253         return ret;
254 }
255 #endif /* CONFIG_ATM_LANE */
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                 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 }