ipv6: by default join ff01::1 and in case of forwarding ff01::2 and ff05:2
[pandora-kernel.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 <linux/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 static void fdb_notify(struct net_bridge *br,
32                        const struct net_bridge_fdb_entry *, int);
33
34 static u32 fdb_salt __read_mostly;
35
36 int __init br_fdb_init(void)
37 {
38         br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
39                                          sizeof(struct net_bridge_fdb_entry),
40                                          0,
41                                          SLAB_HWCACHE_ALIGN, NULL);
42         if (!br_fdb_cache)
43                 return -ENOMEM;
44
45         get_random_bytes(&fdb_salt, sizeof(fdb_salt));
46         return 0;
47 }
48
49 void br_fdb_fini(void)
50 {
51         kmem_cache_destroy(br_fdb_cache);
52 }
53
54
55 /* if topology_changing then use forward_delay (default 15 sec)
56  * otherwise keep longer (default 5 minutes)
57  */
58 static inline unsigned long hold_time(const struct net_bridge *br)
59 {
60         return br->topology_change ? br->forward_delay : br->ageing_time;
61 }
62
63 static inline int has_expired(const struct net_bridge *br,
64                                   const struct net_bridge_fdb_entry *fdb)
65 {
66         return !fdb->is_static &&
67                 time_before_eq(fdb->updated + hold_time(br), jiffies);
68 }
69
70 static inline int br_mac_hash(const unsigned char *mac)
71 {
72         /* use 1 byte of OUI cnd 3 bytes of NIC */
73         u32 key = get_unaligned((u32 *)(mac + 2));
74         return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
75 }
76
77 static void fdb_rcu_free(struct rcu_head *head)
78 {
79         struct net_bridge_fdb_entry *ent
80                 = container_of(head, struct net_bridge_fdb_entry, rcu);
81         kmem_cache_free(br_fdb_cache, ent);
82 }
83
84 static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f)
85 {
86         hlist_del_rcu(&f->hlist);
87         fdb_notify(br, f, RTM_DELNEIGH);
88         call_rcu(&f->rcu, fdb_rcu_free);
89 }
90
91 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
92 {
93         struct net_bridge *br = p->br;
94         int i;
95
96         spin_lock_bh(&br->hash_lock);
97
98         /* Search all chains since old address/hash is unknown */
99         for (i = 0; i < BR_HASH_SIZE; i++) {
100                 struct hlist_node *h;
101                 hlist_for_each(h, &br->hash[i]) {
102                         struct net_bridge_fdb_entry *f;
103
104                         f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
105                         if (f->dst == p && f->is_local) {
106                                 /* maybe another port has same hw addr? */
107                                 struct net_bridge_port *op;
108                                 list_for_each_entry(op, &br->port_list, list) {
109                                         if (op != p &&
110                                             ether_addr_equal(op->dev->dev_addr,
111                                                              f->addr.addr)) {
112                                                 f->dst = op;
113                                                 goto insert;
114                                         }
115                                 }
116
117                                 /* delete old one */
118                                 fdb_delete(br, f);
119                                 goto insert;
120                         }
121                 }
122         }
123  insert:
124         /* insert new address,  may fail if invalid address or dup. */
125         fdb_insert(br, p, newaddr);
126
127         spin_unlock_bh(&br->hash_lock);
128 }
129
130 void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
131 {
132         struct net_bridge_fdb_entry *f;
133
134         /* If old entry was unassociated with any port, then delete it. */
135         f = __br_fdb_get(br, br->dev->dev_addr);
136         if (f && f->is_local && !f->dst)
137                 fdb_delete(br, f);
138
139         fdb_insert(br, NULL, newaddr);
140 }
141
142 void br_fdb_cleanup(unsigned long _data)
143 {
144         struct net_bridge *br = (struct net_bridge *)_data;
145         unsigned long delay = hold_time(br);
146         unsigned long next_timer = jiffies + br->ageing_time;
147         int i;
148
149         spin_lock(&br->hash_lock);
150         for (i = 0; i < BR_HASH_SIZE; i++) {
151                 struct net_bridge_fdb_entry *f;
152                 struct hlist_node *h, *n;
153
154                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
155                         unsigned long this_timer;
156                         if (f->is_static)
157                                 continue;
158                         this_timer = f->updated + delay;
159                         if (time_before_eq(this_timer, jiffies))
160                                 fdb_delete(br, f);
161                         else if (time_before(this_timer, next_timer))
162                                 next_timer = this_timer;
163                 }
164         }
165         spin_unlock(&br->hash_lock);
166
167         mod_timer(&br->gc_timer, round_jiffies_up(next_timer));
168 }
169
170 /* Completely flush all dynamic entries in forwarding database.*/
171 void br_fdb_flush(struct net_bridge *br)
172 {
173         int i;
174
175         spin_lock_bh(&br->hash_lock);
176         for (i = 0; i < BR_HASH_SIZE; i++) {
177                 struct net_bridge_fdb_entry *f;
178                 struct hlist_node *h, *n;
179                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
180                         if (!f->is_static)
181                                 fdb_delete(br, f);
182                 }
183         }
184         spin_unlock_bh(&br->hash_lock);
185 }
186
187 /* Flush all entries referring to a specific port.
188  * if do_all is set also flush static entries
189  */
190 void br_fdb_delete_by_port(struct net_bridge *br,
191                            const struct net_bridge_port *p,
192                            int do_all)
193 {
194         int i;
195
196         spin_lock_bh(&br->hash_lock);
197         for (i = 0; i < BR_HASH_SIZE; i++) {
198                 struct hlist_node *h, *g;
199
200                 hlist_for_each_safe(h, g, &br->hash[i]) {
201                         struct net_bridge_fdb_entry *f
202                                 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
203                         if (f->dst != p)
204                                 continue;
205
206                         if (f->is_static && !do_all)
207                                 continue;
208                         /*
209                          * if multiple ports all have the same device address
210                          * then when one port is deleted, assign
211                          * the local entry to other port
212                          */
213                         if (f->is_local) {
214                                 struct net_bridge_port *op;
215                                 list_for_each_entry(op, &br->port_list, list) {
216                                         if (op != p &&
217                                             ether_addr_equal(op->dev->dev_addr,
218                                                              f->addr.addr)) {
219                                                 f->dst = op;
220                                                 goto skip_delete;
221                                         }
222                                 }
223                         }
224
225                         fdb_delete(br, f);
226                 skip_delete: ;
227                 }
228         }
229         spin_unlock_bh(&br->hash_lock);
230 }
231
232 /* No locking or refcounting, assumes caller has rcu_read_lock */
233 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
234                                           const unsigned char *addr)
235 {
236         struct hlist_node *h;
237         struct net_bridge_fdb_entry *fdb;
238
239         hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
240                 if (ether_addr_equal(fdb->addr.addr, addr)) {
241                         if (unlikely(has_expired(br, fdb)))
242                                 break;
243                         return fdb;
244                 }
245         }
246
247         return NULL;
248 }
249
250 #if IS_ENABLED(CONFIG_ATM_LANE)
251 /* Interface used by ATM LANE hook to test
252  * if an addr is on some other bridge port */
253 int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
254 {
255         struct net_bridge_fdb_entry *fdb;
256         struct net_bridge_port *port;
257         int ret;
258
259         rcu_read_lock();
260         port = br_port_get_rcu(dev);
261         if (!port)
262                 ret = 0;
263         else {
264                 fdb = __br_fdb_get(port->br, addr);
265                 ret = fdb && fdb->dst && fdb->dst->dev != dev &&
266                         fdb->dst->state == BR_STATE_FORWARDING;
267         }
268         rcu_read_unlock();
269
270         return ret;
271 }
272 #endif /* CONFIG_ATM_LANE */
273
274 /*
275  * Fill buffer with forwarding table records in
276  * the API format.
277  */
278 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
279                    unsigned long maxnum, unsigned long skip)
280 {
281         struct __fdb_entry *fe = buf;
282         int i, num = 0;
283         struct hlist_node *h;
284         struct net_bridge_fdb_entry *f;
285
286         memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
287
288         rcu_read_lock();
289         for (i = 0; i < BR_HASH_SIZE; i++) {
290                 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
291                         if (num >= maxnum)
292                                 goto out;
293
294                         if (has_expired(br, f))
295                                 continue;
296
297                         /* ignore pseudo entry for local MAC address */
298                         if (!f->dst)
299                                 continue;
300
301                         if (skip) {
302                                 --skip;
303                                 continue;
304                         }
305
306                         /* convert from internal format to API */
307                         memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
308
309                         /* due to ABI compat need to split into hi/lo */
310                         fe->port_no = f->dst->port_no;
311                         fe->port_hi = f->dst->port_no >> 8;
312
313                         fe->is_local = f->is_local;
314                         if (!f->is_static)
315                                 fe->ageing_timer_value = jiffies_delta_to_clock_t(jiffies - f->updated);
316                         ++fe;
317                         ++num;
318                 }
319         }
320
321  out:
322         rcu_read_unlock();
323
324         return num;
325 }
326
327 static struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
328                                              const unsigned char *addr)
329 {
330         struct hlist_node *h;
331         struct net_bridge_fdb_entry *fdb;
332
333         hlist_for_each_entry(fdb, h, head, hlist) {
334                 if (ether_addr_equal(fdb->addr.addr, addr))
335                         return fdb;
336         }
337         return NULL;
338 }
339
340 static struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head,
341                                                  const unsigned char *addr)
342 {
343         struct hlist_node *h;
344         struct net_bridge_fdb_entry *fdb;
345
346         hlist_for_each_entry_rcu(fdb, h, head, hlist) {
347                 if (ether_addr_equal(fdb->addr.addr, addr))
348                         return fdb;
349         }
350         return NULL;
351 }
352
353 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
354                                                struct net_bridge_port *source,
355                                                const unsigned char *addr)
356 {
357         struct net_bridge_fdb_entry *fdb;
358
359         fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
360         if (fdb) {
361                 memcpy(fdb->addr.addr, addr, ETH_ALEN);
362                 fdb->dst = source;
363                 fdb->is_local = 0;
364                 fdb->is_static = 0;
365                 fdb->updated = fdb->used = jiffies;
366                 hlist_add_head_rcu(&fdb->hlist, head);
367         }
368         return fdb;
369 }
370
371 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
372                   const unsigned char *addr)
373 {
374         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
375         struct net_bridge_fdb_entry *fdb;
376
377         if (!is_valid_ether_addr(addr))
378                 return -EINVAL;
379
380         fdb = fdb_find(head, addr);
381         if (fdb) {
382                 /* it is okay to have multiple ports with same
383                  * address, just use the first one.
384                  */
385                 if (fdb->is_local)
386                         return 0;
387                 br_warn(br, "adding interface %s with same address "
388                        "as a received packet\n",
389                        source->dev->name);
390                 fdb_delete(br, fdb);
391         }
392
393         fdb = fdb_create(head, source, addr);
394         if (!fdb)
395                 return -ENOMEM;
396
397         fdb->is_local = fdb->is_static = 1;
398         fdb_notify(br, fdb, RTM_NEWNEIGH);
399         return 0;
400 }
401
402 /* Add entry for local address of interface */
403 int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
404                   const unsigned char *addr)
405 {
406         int ret;
407
408         spin_lock_bh(&br->hash_lock);
409         ret = fdb_insert(br, source, addr);
410         spin_unlock_bh(&br->hash_lock);
411         return ret;
412 }
413
414 void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
415                    const unsigned char *addr)
416 {
417         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
418         struct net_bridge_fdb_entry *fdb;
419
420         /* some users want to always flood. */
421         if (hold_time(br) == 0)
422                 return;
423
424         /* ignore packets unless we are using this port */
425         if (!(source->state == BR_STATE_LEARNING ||
426               source->state == BR_STATE_FORWARDING))
427                 return;
428
429         fdb = fdb_find_rcu(head, addr);
430         if (likely(fdb)) {
431                 /* attempt to update an entry for a local interface */
432                 if (unlikely(fdb->is_local)) {
433                         if (net_ratelimit())
434                                 br_warn(br, "received packet on %s with "
435                                         "own address as source address\n",
436                                         source->dev->name);
437                 } else {
438                         /* fastpath: update of existing entry */
439                         fdb->dst = source;
440                         fdb->updated = jiffies;
441                 }
442         } else {
443                 spin_lock(&br->hash_lock);
444                 if (likely(!fdb_find(head, addr))) {
445                         fdb = fdb_create(head, source, addr);
446                         if (fdb)
447                                 fdb_notify(br, fdb, RTM_NEWNEIGH);
448                 }
449                 /* else  we lose race and someone else inserts
450                  * it first, don't bother updating
451                  */
452                 spin_unlock(&br->hash_lock);
453         }
454 }
455
456 static int fdb_to_nud(const struct net_bridge_fdb_entry *fdb)
457 {
458         if (fdb->is_local)
459                 return NUD_PERMANENT;
460         else if (fdb->is_static)
461                 return NUD_NOARP;
462         else if (has_expired(fdb->dst->br, fdb))
463                 return NUD_STALE;
464         else
465                 return NUD_REACHABLE;
466 }
467
468 static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
469                          const struct net_bridge_fdb_entry *fdb,
470                          u32 portid, u32 seq, int type, unsigned int flags)
471 {
472         unsigned long now = jiffies;
473         struct nda_cacheinfo ci;
474         struct nlmsghdr *nlh;
475         struct ndmsg *ndm;
476
477         nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
478         if (nlh == NULL)
479                 return -EMSGSIZE;
480
481         ndm = nlmsg_data(nlh);
482         ndm->ndm_family  = AF_BRIDGE;
483         ndm->ndm_pad1    = 0;
484         ndm->ndm_pad2    = 0;
485         ndm->ndm_flags   = 0;
486         ndm->ndm_type    = 0;
487         ndm->ndm_ifindex = fdb->dst ? fdb->dst->dev->ifindex : br->dev->ifindex;
488         ndm->ndm_state   = fdb_to_nud(fdb);
489
490         if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr))
491                 goto nla_put_failure;
492         ci.ndm_used      = jiffies_to_clock_t(now - fdb->used);
493         ci.ndm_confirmed = 0;
494         ci.ndm_updated   = jiffies_to_clock_t(now - fdb->updated);
495         ci.ndm_refcnt    = 0;
496         if (nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
497                 goto nla_put_failure;
498         return nlmsg_end(skb, nlh);
499
500 nla_put_failure:
501         nlmsg_cancel(skb, nlh);
502         return -EMSGSIZE;
503 }
504
505 static inline size_t fdb_nlmsg_size(void)
506 {
507         return NLMSG_ALIGN(sizeof(struct ndmsg))
508                 + nla_total_size(ETH_ALEN) /* NDA_LLADDR */
509                 + nla_total_size(sizeof(struct nda_cacheinfo));
510 }
511
512 static void fdb_notify(struct net_bridge *br,
513                        const struct net_bridge_fdb_entry *fdb, int type)
514 {
515         struct net *net = dev_net(br->dev);
516         struct sk_buff *skb;
517         int err = -ENOBUFS;
518
519         skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
520         if (skb == NULL)
521                 goto errout;
522
523         err = fdb_fill_info(skb, br, fdb, 0, 0, type, 0);
524         if (err < 0) {
525                 /* -EMSGSIZE implies BUG in fdb_nlmsg_size() */
526                 WARN_ON(err == -EMSGSIZE);
527                 kfree_skb(skb);
528                 goto errout;
529         }
530         rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
531         return;
532 errout:
533         if (err < 0)
534                 rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
535 }
536
537 /* Dump information about entries, in response to GETNEIGH */
538 int br_fdb_dump(struct sk_buff *skb,
539                 struct netlink_callback *cb,
540                 struct net_device *dev,
541                 int idx)
542 {
543         struct net_bridge *br = netdev_priv(dev);
544         int i;
545
546         if (!(dev->priv_flags & IFF_EBRIDGE))
547                 goto out;
548
549         for (i = 0; i < BR_HASH_SIZE; i++) {
550                 struct hlist_node *h;
551                 struct net_bridge_fdb_entry *f;
552
553                 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
554                         if (idx < cb->args[0])
555                                 goto skip;
556
557                         if (fdb_fill_info(skb, br, f,
558                                           NETLINK_CB(cb->skb).portid,
559                                           cb->nlh->nlmsg_seq,
560                                           RTM_NEWNEIGH,
561                                           NLM_F_MULTI) < 0)
562                                 break;
563 skip:
564                         ++idx;
565                 }
566         }
567
568 out:
569         return idx;
570 }
571
572 /* Update (create or replace) forwarding database entry */
573 static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr,
574                          __u16 state, __u16 flags)
575 {
576         struct net_bridge *br = source->br;
577         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
578         struct net_bridge_fdb_entry *fdb;
579
580         fdb = fdb_find(head, addr);
581         if (fdb == NULL) {
582                 if (!(flags & NLM_F_CREATE))
583                         return -ENOENT;
584
585                 fdb = fdb_create(head, source, addr);
586                 if (!fdb)
587                         return -ENOMEM;
588                 fdb_notify(br, fdb, RTM_NEWNEIGH);
589         } else {
590                 if (flags & NLM_F_EXCL)
591                         return -EEXIST;
592         }
593
594         if (fdb_to_nud(fdb) != state) {
595                 if (state & NUD_PERMANENT)
596                         fdb->is_local = fdb->is_static = 1;
597                 else if (state & NUD_NOARP) {
598                         fdb->is_local = 0;
599                         fdb->is_static = 1;
600                 } else
601                         fdb->is_local = fdb->is_static = 0;
602
603                 fdb->updated = fdb->used = jiffies;
604                 fdb_notify(br, fdb, RTM_NEWNEIGH);
605         }
606
607         return 0;
608 }
609
610 /* Add new permanent fdb entry with RTM_NEWNEIGH */
611 int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
612                struct net_device *dev,
613                const unsigned char *addr, u16 nlh_flags)
614 {
615         struct net_bridge_port *p;
616         int err = 0;
617
618         if (!(ndm->ndm_state & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE))) {
619                 pr_info("bridge: RTM_NEWNEIGH with invalid state %#x\n", ndm->ndm_state);
620                 return -EINVAL;
621         }
622
623         p = br_port_get_rtnl(dev);
624         if (p == NULL) {
625                 pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n",
626                         dev->name);
627                 return -EINVAL;
628         }
629
630         if (ndm->ndm_flags & NTF_USE) {
631                 rcu_read_lock();
632                 br_fdb_update(p->br, p, addr);
633                 rcu_read_unlock();
634         } else {
635                 spin_lock_bh(&p->br->hash_lock);
636                 err = fdb_add_entry(p, addr, ndm->ndm_state, nlh_flags);
637                 spin_unlock_bh(&p->br->hash_lock);
638         }
639
640         return err;
641 }
642
643 static int fdb_delete_by_addr(struct net_bridge_port *p, const u8 *addr)
644 {
645         struct net_bridge *br = p->br;
646         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
647         struct net_bridge_fdb_entry *fdb;
648
649         fdb = fdb_find(head, addr);
650         if (!fdb)
651                 return -ENOENT;
652
653         fdb_delete(p->br, fdb);
654         return 0;
655 }
656
657 /* Remove neighbor entry with RTM_DELNEIGH */
658 int br_fdb_delete(struct ndmsg *ndm, struct net_device *dev,
659                   const unsigned char *addr)
660 {
661         struct net_bridge_port *p;
662         int err;
663
664         p = br_port_get_rtnl(dev);
665         if (p == NULL) {
666                 pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n",
667                         dev->name);
668                 return -EINVAL;
669         }
670
671         spin_lock_bh(&p->br->hash_lock);
672         err = fdb_delete_by_addr(p, addr);
673         spin_unlock_bh(&p->br->hash_lock);
674
675         return err;
676 }