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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/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->ageing_time; |
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 | mod_timer(&br->gc_timer, round_jiffies_up(next_timer)); |
153 | } |
154 | |
155 | /* Completely flush all dynamic entries in forwarding database.*/ |
156 | void br_fdb_flush(struct net_bridge *br) |
157 | { |
158 | int i; |
159 | |
160 | spin_lock_bh(&br->hash_lock); |
161 | for (i = 0; i < BR_HASH_SIZE; i++) { |
162 | struct net_bridge_fdb_entry *f; |
163 | struct hlist_node *h, *n; |
164 | hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) { |
165 | if (!f->is_static) |
166 | fdb_delete(f); |
167 | } |
168 | } |
169 | spin_unlock_bh(&br->hash_lock); |
170 | } |
171 | |
172 | /* Flush all entries referring to a specific port. |
173 | * if do_all is set also flush static entries |
174 | */ |
175 | void br_fdb_delete_by_port(struct net_bridge *br, |
176 | const struct net_bridge_port *p, |
177 | int do_all) |
178 | { |
179 | int i; |
180 | |
181 | spin_lock_bh(&br->hash_lock); |
182 | for (i = 0; i < BR_HASH_SIZE; i++) { |
183 | struct hlist_node *h, *g; |
184 | |
185 | hlist_for_each_safe(h, g, &br->hash[i]) { |
186 | struct net_bridge_fdb_entry *f |
187 | = hlist_entry(h, struct net_bridge_fdb_entry, hlist); |
188 | if (f->dst != p) |
189 | continue; |
190 | |
191 | if (f->is_static && !do_all) |
192 | continue; |
193 | /* |
194 | * if multiple ports all have the same device address |
195 | * then when one port is deleted, assign |
196 | * the local entry to other port |
197 | */ |
198 | if (f->is_local) { |
199 | struct net_bridge_port *op; |
200 | list_for_each_entry(op, &br->port_list, list) { |
201 | if (op != p && |
202 | !compare_ether_addr(op->dev->dev_addr, |
203 | f->addr.addr)) { |
204 | f->dst = op; |
205 | goto skip_delete; |
206 | } |
207 | } |
208 | } |
209 | |
210 | fdb_delete(f); |
211 | skip_delete: ; |
212 | } |
213 | } |
214 | spin_unlock_bh(&br->hash_lock); |
215 | } |
216 | |
217 | /* No locking or refcounting, assumes caller has rcu_read_lock */ |
218 | struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br, |
219 | const unsigned char *addr) |
220 | { |
221 | struct hlist_node *h; |
222 | struct net_bridge_fdb_entry *fdb; |
223 | |
224 | hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) { |
225 | if (!compare_ether_addr(fdb->addr.addr, addr)) { |
226 | if (unlikely(has_expired(br, fdb))) |
227 | break; |
228 | return fdb; |
229 | } |
230 | } |
231 | |
232 | return NULL; |
233 | } |
234 | |
235 | #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE) |
236 | /* Interface used by ATM LANE hook to test |
237 | * if an addr is on some other bridge port */ |
238 | int br_fdb_test_addr(struct net_device *dev, unsigned char *addr) |
239 | { |
240 | struct net_bridge_fdb_entry *fdb; |
241 | struct net_bridge_port *port; |
242 | int ret; |
243 | |
244 | rcu_read_lock(); |
245 | port = br_port_get_rcu(dev); |
246 | if (!port) |
247 | ret = 0; |
248 | else { |
249 | fdb = __br_fdb_get(port->br, addr); |
250 | ret = fdb && fdb->dst->dev != dev && |
251 | fdb->dst->state == BR_STATE_FORWARDING; |
252 | } |
253 | rcu_read_unlock(); |
254 | |
255 | return ret; |
256 | } |
257 | #endif /* CONFIG_ATM_LANE */ |
258 | |
259 | /* |
260 | * Fill buffer with forwarding table records in |
261 | * the API format. |
262 | */ |
263 | int br_fdb_fillbuf(struct net_bridge *br, void *buf, |
264 | unsigned long maxnum, unsigned long skip) |
265 | { |
266 | struct __fdb_entry *fe = buf; |
267 | int i, num = 0; |
268 | struct hlist_node *h; |
269 | struct net_bridge_fdb_entry *f; |
270 | |
271 | memset(buf, 0, maxnum*sizeof(struct __fdb_entry)); |
272 | |
273 | rcu_read_lock(); |
274 | for (i = 0; i < BR_HASH_SIZE; i++) { |
275 | hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) { |
276 | if (num >= maxnum) |
277 | goto out; |
278 | |
279 | if (has_expired(br, f)) |
280 | continue; |
281 | |
282 | if (skip) { |
283 | --skip; |
284 | continue; |
285 | } |
286 | |
287 | /* convert from internal format to API */ |
288 | memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN); |
289 | |
290 | /* due to ABI compat need to split into hi/lo */ |
291 | fe->port_no = f->dst->port_no; |
292 | fe->port_hi = f->dst->port_no >> 8; |
293 | |
294 | fe->is_local = f->is_local; |
295 | if (!f->is_static) |
296 | fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer); |
297 | ++fe; |
298 | ++num; |
299 | } |
300 | } |
301 | |
302 | out: |
303 | rcu_read_unlock(); |
304 | |
305 | return num; |
306 | } |
307 | |
308 | static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head, |
309 | const unsigned char *addr) |
310 | { |
311 | struct hlist_node *h; |
312 | struct net_bridge_fdb_entry *fdb; |
313 | |
314 | hlist_for_each_entry_rcu(fdb, h, head, hlist) { |
315 | if (!compare_ether_addr(fdb->addr.addr, addr)) |
316 | return fdb; |
317 | } |
318 | return NULL; |
319 | } |
320 | |
321 | static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head, |
322 | struct net_bridge_port *source, |
323 | const unsigned char *addr, |
324 | int is_local) |
325 | { |
326 | struct net_bridge_fdb_entry *fdb; |
327 | |
328 | fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC); |
329 | if (fdb) { |
330 | memcpy(fdb->addr.addr, addr, ETH_ALEN); |
331 | fdb->dst = source; |
332 | fdb->is_local = is_local; |
333 | fdb->is_static = is_local; |
334 | fdb->ageing_timer = jiffies; |
335 | |
336 | hlist_add_head_rcu(&fdb->hlist, head); |
337 | } |
338 | return fdb; |
339 | } |
340 | |
341 | static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source, |
342 | const unsigned char *addr) |
343 | { |
344 | struct hlist_head *head = &br->hash[br_mac_hash(addr)]; |
345 | struct net_bridge_fdb_entry *fdb; |
346 | |
347 | if (!is_valid_ether_addr(addr)) |
348 | return -EINVAL; |
349 | |
350 | fdb = fdb_find(head, addr); |
351 | if (fdb) { |
352 | /* it is okay to have multiple ports with same |
353 | * address, just use the first one. |
354 | */ |
355 | if (fdb->is_local) |
356 | return 0; |
357 | br_warn(br, "adding interface %s 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 | br_warn(br, "received packet on %s 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 | } |
418 |
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