3 * Linux ethernet bridge
6 * Lennert Buytenhek <buytenh@gnu.org>
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.
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 <linux/if_vlan.h>
27 #include "br_private.h"
29 static struct kmem_cache *br_fdb_cache __read_mostly;
30 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
31 const unsigned char *addr, u16 vid);
32 static void fdb_notify(struct net_bridge *br,
33 const struct net_bridge_fdb_entry *, int);
35 static u32 fdb_salt __read_mostly;
37 int __init br_fdb_init(void)
39 br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
40 sizeof(struct net_bridge_fdb_entry),
42 SLAB_HWCACHE_ALIGN, NULL);
46 get_random_bytes(&fdb_salt, sizeof(fdb_salt));
50 void br_fdb_fini(void)
52 kmem_cache_destroy(br_fdb_cache);
56 /* if topology_changing then use forward_delay (default 15 sec)
57 * otherwise keep longer (default 5 minutes)
59 static inline unsigned long hold_time(const struct net_bridge *br)
61 return br->topology_change ? br->forward_delay : br->ageing_time;
64 static inline int has_expired(const struct net_bridge *br,
65 const struct net_bridge_fdb_entry *fdb)
67 return !fdb->is_static &&
68 time_before_eq(fdb->updated + hold_time(br), jiffies);
71 static inline int br_mac_hash(const unsigned char *mac, __u16 vid)
73 /* use 1 byte of OUI and 3 bytes of NIC */
74 u32 key = get_unaligned((u32 *)(mac + 2));
75 return jhash_2words(key, vid, fdb_salt) & (BR_HASH_SIZE - 1);
78 static void fdb_rcu_free(struct rcu_head *head)
80 struct net_bridge_fdb_entry *ent
81 = container_of(head, struct net_bridge_fdb_entry, rcu);
82 kmem_cache_free(br_fdb_cache, ent);
85 static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f)
87 hlist_del_rcu(&f->hlist);
88 fdb_notify(br, f, RTM_DELNEIGH);
89 call_rcu(&f->rcu, fdb_rcu_free);
92 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
94 struct net_bridge *br = p->br;
95 struct net_port_vlans *pv = nbp_get_vlan_info(p);
100 spin_lock_bh(&br->hash_lock);
102 /* Search all chains since old address/hash is unknown */
103 for (i = 0; i < BR_HASH_SIZE; i++) {
104 struct hlist_node *h;
105 hlist_for_each(h, &br->hash[i]) {
106 struct net_bridge_fdb_entry *f;
108 f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
109 if (f->dst == p && f->is_local && !f->added_by_user) {
110 /* maybe another port has same hw addr? */
111 struct net_bridge_port *op;
112 u16 vid = f->vlan_id;
113 list_for_each_entry(op, &br->port_list, list) {
115 ether_addr_equal(op->dev->dev_addr,
117 (!vid || nbp_vlan_find(op, vid))) {
123 /* maybe bridge device has same hw addr? */
124 if (ether_addr_equal(br->dev->dev_addr,
126 (!vid || br_vlan_find(br, vid))) {
134 /* if this port has no vlan information
135 * configured, we can safely be done at
145 /* insert new address, may fail if invalid address or dup. */
146 fdb_insert(br, p, newaddr, 0);
151 /* Now add entries for every VLAN configured on the port.
152 * This function runs under RTNL so the bitmap will not change
155 for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID)
156 fdb_insert(br, p, newaddr, vid);
159 spin_unlock_bh(&br->hash_lock);
162 void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
164 struct net_bridge_fdb_entry *f;
165 struct net_port_vlans *pv;
168 /* If old entry was unassociated with any port, then delete it. */
169 f = __br_fdb_get(br, br->dev->dev_addr, 0);
170 if (f && f->is_local && !f->dst)
173 fdb_insert(br, NULL, newaddr, 0);
175 /* Now remove and add entries for every VLAN configured on the
176 * bridge. This function runs under RTNL so the bitmap will not
177 * change from under us.
179 pv = br_get_vlan_info(br);
183 for_each_set_bit_from(vid, pv->vlan_bitmap, VLAN_N_VID) {
184 f = __br_fdb_get(br, br->dev->dev_addr, vid);
185 if (f && f->is_local && !f->dst)
187 fdb_insert(br, NULL, newaddr, vid);
191 void br_fdb_cleanup(unsigned long _data)
193 struct net_bridge *br = (struct net_bridge *)_data;
194 unsigned long delay = hold_time(br);
195 unsigned long next_timer = jiffies + br->ageing_time;
198 spin_lock(&br->hash_lock);
199 for (i = 0; i < BR_HASH_SIZE; i++) {
200 struct net_bridge_fdb_entry *f;
201 struct hlist_node *n;
203 hlist_for_each_entry_safe(f, n, &br->hash[i], hlist) {
204 unsigned long this_timer;
207 this_timer = f->updated + delay;
208 if (time_before_eq(this_timer, jiffies))
210 else if (time_before(this_timer, next_timer))
211 next_timer = this_timer;
214 spin_unlock(&br->hash_lock);
216 mod_timer(&br->gc_timer, round_jiffies_up(next_timer));
219 /* Completely flush all dynamic entries in forwarding database.*/
220 void br_fdb_flush(struct net_bridge *br)
224 spin_lock_bh(&br->hash_lock);
225 for (i = 0; i < BR_HASH_SIZE; i++) {
226 struct net_bridge_fdb_entry *f;
227 struct hlist_node *n;
228 hlist_for_each_entry_safe(f, n, &br->hash[i], hlist) {
233 spin_unlock_bh(&br->hash_lock);
236 /* Flush all entries referring to a specific port.
237 * if do_all is set also flush static entries
239 void br_fdb_delete_by_port(struct net_bridge *br,
240 const struct net_bridge_port *p,
245 spin_lock_bh(&br->hash_lock);
246 for (i = 0; i < BR_HASH_SIZE; i++) {
247 struct hlist_node *h, *g;
249 hlist_for_each_safe(h, g, &br->hash[i]) {
250 struct net_bridge_fdb_entry *f
251 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
255 if (f->is_static && !do_all)
258 * if multiple ports all have the same device address
259 * then when one port is deleted, assign
260 * the local entry to other port
263 struct net_bridge_port *op;
264 list_for_each_entry(op, &br->port_list, list) {
266 ether_addr_equal(op->dev->dev_addr,
269 f->added_by_user = 0;
279 spin_unlock_bh(&br->hash_lock);
282 /* No locking or refcounting, assumes caller has rcu_read_lock */
283 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
284 const unsigned char *addr,
287 struct net_bridge_fdb_entry *fdb;
289 hlist_for_each_entry_rcu(fdb,
290 &br->hash[br_mac_hash(addr, vid)], hlist) {
291 if (ether_addr_equal(fdb->addr.addr, addr) &&
292 fdb->vlan_id == vid) {
293 if (unlikely(has_expired(br, fdb)))
302 #if IS_ENABLED(CONFIG_ATM_LANE)
303 /* Interface used by ATM LANE hook to test
304 * if an addr is on some other bridge port */
305 int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
307 struct net_bridge_fdb_entry *fdb;
308 struct net_bridge_port *port;
312 port = br_port_get_rcu(dev);
316 fdb = __br_fdb_get(port->br, addr, 0);
317 ret = fdb && fdb->dst && fdb->dst->dev != dev &&
318 fdb->dst->state == BR_STATE_FORWARDING;
324 #endif /* CONFIG_ATM_LANE */
327 * Fill buffer with forwarding table records in
330 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
331 unsigned long maxnum, unsigned long skip)
333 struct __fdb_entry *fe = buf;
335 struct net_bridge_fdb_entry *f;
337 memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
340 for (i = 0; i < BR_HASH_SIZE; i++) {
341 hlist_for_each_entry_rcu(f, &br->hash[i], hlist) {
345 if (has_expired(br, f))
348 /* ignore pseudo entry for local MAC address */
357 /* convert from internal format to API */
358 memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
360 /* due to ABI compat need to split into hi/lo */
361 fe->port_no = f->dst->port_no;
362 fe->port_hi = f->dst->port_no >> 8;
364 fe->is_local = f->is_local;
366 fe->ageing_timer_value = jiffies_delta_to_clock_t(jiffies - f->updated);
378 static struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
379 const unsigned char *addr,
382 struct net_bridge_fdb_entry *fdb;
384 hlist_for_each_entry(fdb, head, hlist) {
385 if (ether_addr_equal(fdb->addr.addr, addr) &&
392 static struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head,
393 const unsigned char *addr,
396 struct net_bridge_fdb_entry *fdb;
398 hlist_for_each_entry_rcu(fdb, head, hlist) {
399 if (ether_addr_equal(fdb->addr.addr, addr) &&
406 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
407 struct net_bridge_port *source,
408 const unsigned char *addr,
411 struct net_bridge_fdb_entry *fdb;
413 fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
415 memcpy(fdb->addr.addr, addr, ETH_ALEN);
420 fdb->added_by_user = 0;
421 fdb->updated = fdb->used = jiffies;
422 hlist_add_head_rcu(&fdb->hlist, head);
427 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
428 const unsigned char *addr, u16 vid)
430 struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
431 struct net_bridge_fdb_entry *fdb;
433 if (!is_valid_ether_addr(addr))
436 fdb = fdb_find(head, addr, vid);
438 /* it is okay to have multiple ports with same
439 * address, just use the first one.
443 br_warn(br, "adding interface %s with same address "
444 "as a received packet\n",
445 source ? source->dev->name : br->dev->name);
449 fdb = fdb_create(head, source, addr, vid);
453 fdb->is_local = fdb->is_static = 1;
454 fdb_notify(br, fdb, RTM_NEWNEIGH);
458 /* Add entry for local address of interface */
459 int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
460 const unsigned char *addr, u16 vid)
464 spin_lock_bh(&br->hash_lock);
465 ret = fdb_insert(br, source, addr, vid);
466 spin_unlock_bh(&br->hash_lock);
470 void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
471 const unsigned char *addr, u16 vid, bool added_by_user)
473 struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
474 struct net_bridge_fdb_entry *fdb;
476 /* some users want to always flood. */
477 if (hold_time(br) == 0)
480 /* ignore packets unless we are using this port */
481 if (!(source->state == BR_STATE_LEARNING ||
482 source->state == BR_STATE_FORWARDING))
485 fdb = fdb_find_rcu(head, addr, vid);
487 /* attempt to update an entry for a local interface */
488 if (unlikely(fdb->is_local)) {
490 br_warn(br, "received packet on %s with "
491 "own address as source address\n",
494 /* fastpath: update of existing entry */
496 fdb->updated = jiffies;
497 if (unlikely(added_by_user))
498 fdb->added_by_user = 1;
501 spin_lock(&br->hash_lock);
502 if (likely(!fdb_find(head, addr, vid))) {
503 fdb = fdb_create(head, source, addr, vid);
505 if (unlikely(added_by_user))
506 fdb->added_by_user = 1;
507 fdb_notify(br, fdb, RTM_NEWNEIGH);
510 /* else we lose race and someone else inserts
511 * it first, don't bother updating
513 spin_unlock(&br->hash_lock);
517 static int fdb_to_nud(const struct net_bridge_fdb_entry *fdb)
520 return NUD_PERMANENT;
521 else if (fdb->is_static)
523 else if (has_expired(fdb->dst->br, fdb))
526 return NUD_REACHABLE;
529 static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
530 const struct net_bridge_fdb_entry *fdb,
531 u32 portid, u32 seq, int type, unsigned int flags)
533 unsigned long now = jiffies;
534 struct nda_cacheinfo ci;
535 struct nlmsghdr *nlh;
538 nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
542 ndm = nlmsg_data(nlh);
543 ndm->ndm_family = AF_BRIDGE;
548 ndm->ndm_ifindex = fdb->dst ? fdb->dst->dev->ifindex : br->dev->ifindex;
549 ndm->ndm_state = fdb_to_nud(fdb);
551 if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr))
552 goto nla_put_failure;
553 ci.ndm_used = jiffies_to_clock_t(now - fdb->used);
554 ci.ndm_confirmed = 0;
555 ci.ndm_updated = jiffies_to_clock_t(now - fdb->updated);
557 if (nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
558 goto nla_put_failure;
560 if (nla_put(skb, NDA_VLAN, sizeof(u16), &fdb->vlan_id))
561 goto nla_put_failure;
563 return nlmsg_end(skb, nlh);
566 nlmsg_cancel(skb, nlh);
570 static inline size_t fdb_nlmsg_size(void)
572 return NLMSG_ALIGN(sizeof(struct ndmsg))
573 + nla_total_size(ETH_ALEN) /* NDA_LLADDR */
574 + nla_total_size(sizeof(u16)) /* NDA_VLAN */
575 + nla_total_size(sizeof(struct nda_cacheinfo));
578 static void fdb_notify(struct net_bridge *br,
579 const struct net_bridge_fdb_entry *fdb, int type)
581 struct net *net = dev_net(br->dev);
585 skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
589 err = fdb_fill_info(skb, br, fdb, 0, 0, type, 0);
591 /* -EMSGSIZE implies BUG in fdb_nlmsg_size() */
592 WARN_ON(err == -EMSGSIZE);
596 rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
599 rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
602 /* Dump information about entries, in response to GETNEIGH */
603 int br_fdb_dump(struct sk_buff *skb,
604 struct netlink_callback *cb,
605 struct net_device *dev,
608 struct net_bridge *br = netdev_priv(dev);
611 if (!(dev->priv_flags & IFF_EBRIDGE))
614 for (i = 0; i < BR_HASH_SIZE; i++) {
615 struct net_bridge_fdb_entry *f;
617 hlist_for_each_entry_rcu(f, &br->hash[i], hlist) {
618 if (idx < cb->args[0])
621 if (fdb_fill_info(skb, br, f,
622 NETLINK_CB(cb->skb).portid,
636 /* Update (create or replace) forwarding database entry */
637 static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr,
638 __u16 state, __u16 flags, __u16 vid)
640 struct net_bridge *br = source->br;
641 struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
642 struct net_bridge_fdb_entry *fdb;
643 bool modified = false;
645 fdb = fdb_find(head, addr, vid);
647 if (!(flags & NLM_F_CREATE))
650 fdb = fdb_create(head, source, addr, vid);
656 if (flags & NLM_F_EXCL)
659 if (fdb->dst != source) {
665 if (fdb_to_nud(fdb) != state) {
666 if (state & NUD_PERMANENT)
667 fdb->is_local = fdb->is_static = 1;
668 else if (state & NUD_NOARP) {
672 fdb->is_local = fdb->is_static = 0;
676 fdb->added_by_user = 1;
680 fdb->updated = jiffies;
681 fdb_notify(br, fdb, RTM_NEWNEIGH);
687 static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge_port *p,
688 const unsigned char *addr, u16 nlh_flags, u16 vid)
692 if (ndm->ndm_flags & NTF_USE) {
694 br_fdb_update(p->br, p, addr, vid, true);
697 spin_lock_bh(&p->br->hash_lock);
698 err = fdb_add_entry(p, addr, ndm->ndm_state,
700 spin_unlock_bh(&p->br->hash_lock);
706 /* Add new permanent fdb entry with RTM_NEWNEIGH */
707 int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
708 struct net_device *dev,
709 const unsigned char *addr, u16 nlh_flags)
711 struct net_bridge_port *p;
713 struct net_port_vlans *pv;
714 unsigned short vid = VLAN_N_VID;
716 if (!(ndm->ndm_state & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE))) {
717 pr_info("bridge: RTM_NEWNEIGH with invalid state %#x\n", ndm->ndm_state);
722 if (nla_len(tb[NDA_VLAN]) != sizeof(unsigned short)) {
723 pr_info("bridge: RTM_NEWNEIGH with invalid vlan\n");
727 vid = nla_get_u16(tb[NDA_VLAN]);
729 if (!vid || vid >= VLAN_VID_MASK) {
730 pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
736 if (is_zero_ether_addr(addr)) {
737 pr_info("bridge: RTM_NEWNEIGH with invalid ether address\n");
741 p = br_port_get_rtnl(dev);
743 pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n",
748 pv = nbp_get_vlan_info(p);
749 if (vid != VLAN_N_VID) {
750 if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
751 pr_info("bridge: RTM_NEWNEIGH with unconfigured "
752 "vlan %d on port %s\n", vid, dev->name);
756 /* VID was specified, so use it. */
757 err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
759 if (!pv || bitmap_empty(pv->vlan_bitmap, VLAN_N_VID)) {
760 err = __br_fdb_add(ndm, p, addr, nlh_flags, 0);
764 /* We have vlans configured on this port and user didn't
765 * specify a VLAN. To be nice, add/update entry for every
768 for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
769 err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
779 int fdb_delete_by_addr(struct net_bridge *br, const u8 *addr,
782 struct hlist_head *head = &br->hash[br_mac_hash(addr, vlan)];
783 struct net_bridge_fdb_entry *fdb;
785 fdb = fdb_find(head, addr, vlan);
793 static int __br_fdb_delete(struct net_bridge_port *p,
794 const unsigned char *addr, u16 vid)
798 spin_lock_bh(&p->br->hash_lock);
799 err = fdb_delete_by_addr(p->br, addr, vid);
800 spin_unlock_bh(&p->br->hash_lock);
805 /* Remove neighbor entry with RTM_DELNEIGH */
806 int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
807 struct net_device *dev,
808 const unsigned char *addr)
810 struct net_bridge_port *p;
812 struct net_port_vlans *pv;
813 unsigned short vid = VLAN_N_VID;
816 if (nla_len(tb[NDA_VLAN]) != sizeof(unsigned short)) {
817 pr_info("bridge: RTM_NEWNEIGH with invalid vlan\n");
821 vid = nla_get_u16(tb[NDA_VLAN]);
823 if (!vid || vid >= VLAN_VID_MASK) {
824 pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
829 p = br_port_get_rtnl(dev);
831 pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n",
836 pv = nbp_get_vlan_info(p);
837 if (vid != VLAN_N_VID) {
838 if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
839 pr_info("bridge: RTM_DELNEIGH with unconfigured "
840 "vlan %d on port %s\n", vid, dev->name);
844 err = __br_fdb_delete(p, addr, vid);
846 if (!pv || bitmap_empty(pv->vlan_bitmap, VLAN_N_VID)) {
847 err = __br_fdb_delete(p, addr, 0);
851 /* We have vlans configured on this port and user didn't
852 * specify a VLAN. To be nice, add/update entry for every
856 for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
857 err &= __br_fdb_delete(p, addr, vid);