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 bool no_vlan = (nbp_get_vlan_info(p) == NULL) ? true : false;
98 spin_lock_bh(&br->hash_lock);
100 /* Search all chains since old address/hash is unknown */
101 for (i = 0; i < BR_HASH_SIZE; i++) {
102 struct hlist_node *h;
103 hlist_for_each(h, &br->hash[i]) {
104 struct net_bridge_fdb_entry *f;
106 f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
107 if (f->dst == p && f->is_local) {
108 /* maybe another port has same hw addr? */
109 struct net_bridge_port *op;
110 u16 vid = f->vlan_id;
111 list_for_each_entry(op, &br->port_list, list) {
113 ether_addr_equal(op->dev->dev_addr,
115 nbp_vlan_find(op, vid)) {
124 /* insert new address, may fail if invalid
127 fdb_insert(br, p, newaddr, vid);
129 /* if this port has no vlan information
130 * configured, we can safely be done at
140 spin_unlock_bh(&br->hash_lock);
143 void br_fdb_change_mac_address(struct net_bridge *br, const u8 *newaddr)
145 struct net_bridge_fdb_entry *f;
146 struct net_port_vlans *pv;
149 /* If old entry was unassociated with any port, then delete it. */
150 f = __br_fdb_get(br, br->dev->dev_addr, 0);
151 if (f && f->is_local && !f->dst)
154 fdb_insert(br, NULL, newaddr, 0);
156 /* Now remove and add entries for every VLAN configured on the
157 * bridge. This function runs under RTNL so the bitmap will not
158 * change from under us.
160 pv = br_get_vlan_info(br);
164 for_each_set_bit_from(vid, pv->vlan_bitmap, VLAN_N_VID) {
165 f = __br_fdb_get(br, br->dev->dev_addr, vid);
166 if (f && f->is_local && !f->dst)
168 fdb_insert(br, NULL, newaddr, vid);
172 void br_fdb_cleanup(unsigned long _data)
174 struct net_bridge *br = (struct net_bridge *)_data;
175 unsigned long delay = hold_time(br);
176 unsigned long next_timer = jiffies + br->ageing_time;
179 spin_lock(&br->hash_lock);
180 for (i = 0; i < BR_HASH_SIZE; i++) {
181 struct net_bridge_fdb_entry *f;
182 struct hlist_node *n;
184 hlist_for_each_entry_safe(f, n, &br->hash[i], hlist) {
185 unsigned long this_timer;
188 this_timer = f->updated + delay;
189 if (time_before_eq(this_timer, jiffies))
191 else if (time_before(this_timer, next_timer))
192 next_timer = this_timer;
195 spin_unlock(&br->hash_lock);
197 mod_timer(&br->gc_timer, round_jiffies_up(next_timer));
200 /* Completely flush all dynamic entries in forwarding database.*/
201 void br_fdb_flush(struct net_bridge *br)
205 spin_lock_bh(&br->hash_lock);
206 for (i = 0; i < BR_HASH_SIZE; i++) {
207 struct net_bridge_fdb_entry *f;
208 struct hlist_node *n;
209 hlist_for_each_entry_safe(f, n, &br->hash[i], hlist) {
214 spin_unlock_bh(&br->hash_lock);
217 /* Flush all entries referring to a specific port.
218 * if do_all is set also flush static entries
220 void br_fdb_delete_by_port(struct net_bridge *br,
221 const struct net_bridge_port *p,
226 spin_lock_bh(&br->hash_lock);
227 for (i = 0; i < BR_HASH_SIZE; i++) {
228 struct hlist_node *h, *g;
230 hlist_for_each_safe(h, g, &br->hash[i]) {
231 struct net_bridge_fdb_entry *f
232 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
236 if (f->is_static && !do_all)
239 * if multiple ports all have the same device address
240 * then when one port is deleted, assign
241 * the local entry to other port
244 struct net_bridge_port *op;
245 list_for_each_entry(op, &br->port_list, list) {
247 ether_addr_equal(op->dev->dev_addr,
259 spin_unlock_bh(&br->hash_lock);
262 /* No locking or refcounting, assumes caller has rcu_read_lock */
263 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
264 const unsigned char *addr,
267 struct net_bridge_fdb_entry *fdb;
269 hlist_for_each_entry_rcu(fdb,
270 &br->hash[br_mac_hash(addr, vid)], hlist) {
271 if (ether_addr_equal(fdb->addr.addr, addr) &&
272 fdb->vlan_id == vid) {
273 if (unlikely(has_expired(br, fdb)))
282 #if IS_ENABLED(CONFIG_ATM_LANE)
283 /* Interface used by ATM LANE hook to test
284 * if an addr is on some other bridge port */
285 int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
287 struct net_bridge_fdb_entry *fdb;
288 struct net_bridge_port *port;
292 port = br_port_get_rcu(dev);
296 fdb = __br_fdb_get(port->br, addr, 0);
297 ret = fdb && fdb->dst && fdb->dst->dev != dev &&
298 fdb->dst->state == BR_STATE_FORWARDING;
304 #endif /* CONFIG_ATM_LANE */
307 * Fill buffer with forwarding table records in
310 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
311 unsigned long maxnum, unsigned long skip)
313 struct __fdb_entry *fe = buf;
315 struct net_bridge_fdb_entry *f;
317 memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
320 for (i = 0; i < BR_HASH_SIZE; i++) {
321 hlist_for_each_entry_rcu(f, &br->hash[i], hlist) {
325 if (has_expired(br, f))
328 /* ignore pseudo entry for local MAC address */
337 /* convert from internal format to API */
338 memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
340 /* due to ABI compat need to split into hi/lo */
341 fe->port_no = f->dst->port_no;
342 fe->port_hi = f->dst->port_no >> 8;
344 fe->is_local = f->is_local;
346 fe->ageing_timer_value = jiffies_delta_to_clock_t(jiffies - f->updated);
358 static struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
359 const unsigned char *addr,
362 struct net_bridge_fdb_entry *fdb;
364 hlist_for_each_entry(fdb, head, hlist) {
365 if (ether_addr_equal(fdb->addr.addr, addr) &&
372 static struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head,
373 const unsigned char *addr,
376 struct net_bridge_fdb_entry *fdb;
378 hlist_for_each_entry_rcu(fdb, head, hlist) {
379 if (ether_addr_equal(fdb->addr.addr, addr) &&
386 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
387 struct net_bridge_port *source,
388 const unsigned char *addr,
391 struct net_bridge_fdb_entry *fdb;
393 fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
395 memcpy(fdb->addr.addr, addr, ETH_ALEN);
400 fdb->updated = fdb->used = jiffies;
401 hlist_add_head_rcu(&fdb->hlist, head);
406 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
407 const unsigned char *addr, u16 vid)
409 struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
410 struct net_bridge_fdb_entry *fdb;
412 if (!is_valid_ether_addr(addr))
415 fdb = fdb_find(head, addr, vid);
417 /* it is okay to have multiple ports with same
418 * address, just use the first one.
422 br_warn(br, "adding interface %s with same address "
423 "as a received packet\n",
424 source ? source->dev->name : br->dev->name);
428 fdb = fdb_create(head, source, addr, vid);
432 fdb->is_local = fdb->is_static = 1;
433 fdb_notify(br, fdb, RTM_NEWNEIGH);
437 /* Add entry for local address of interface */
438 int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
439 const unsigned char *addr, u16 vid)
443 spin_lock_bh(&br->hash_lock);
444 ret = fdb_insert(br, source, addr, vid);
445 spin_unlock_bh(&br->hash_lock);
449 void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
450 const unsigned char *addr, u16 vid)
452 struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
453 struct net_bridge_fdb_entry *fdb;
455 /* some users want to always flood. */
456 if (hold_time(br) == 0)
459 /* ignore packets unless we are using this port */
460 if (!(source->state == BR_STATE_LEARNING ||
461 source->state == BR_STATE_FORWARDING))
464 fdb = fdb_find_rcu(head, addr, vid);
466 /* attempt to update an entry for a local interface */
467 if (unlikely(fdb->is_local)) {
469 br_warn(br, "received packet on %s with "
470 "own address as source address\n",
473 /* fastpath: update of existing entry */
475 fdb->updated = jiffies;
478 spin_lock(&br->hash_lock);
479 if (likely(!fdb_find(head, addr, vid))) {
480 fdb = fdb_create(head, source, addr, vid);
482 fdb_notify(br, fdb, RTM_NEWNEIGH);
484 /* else we lose race and someone else inserts
485 * it first, don't bother updating
487 spin_unlock(&br->hash_lock);
491 static int fdb_to_nud(const struct net_bridge_fdb_entry *fdb)
494 return NUD_PERMANENT;
495 else if (fdb->is_static)
497 else if (has_expired(fdb->dst->br, fdb))
500 return NUD_REACHABLE;
503 static int fdb_fill_info(struct sk_buff *skb, const struct net_bridge *br,
504 const struct net_bridge_fdb_entry *fdb,
505 u32 portid, u32 seq, int type, unsigned int flags)
507 unsigned long now = jiffies;
508 struct nda_cacheinfo ci;
509 struct nlmsghdr *nlh;
512 nlh = nlmsg_put(skb, portid, seq, type, sizeof(*ndm), flags);
516 ndm = nlmsg_data(nlh);
517 ndm->ndm_family = AF_BRIDGE;
522 ndm->ndm_ifindex = fdb->dst ? fdb->dst->dev->ifindex : br->dev->ifindex;
523 ndm->ndm_state = fdb_to_nud(fdb);
525 if (nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr))
526 goto nla_put_failure;
527 ci.ndm_used = jiffies_to_clock_t(now - fdb->used);
528 ci.ndm_confirmed = 0;
529 ci.ndm_updated = jiffies_to_clock_t(now - fdb->updated);
531 if (nla_put(skb, NDA_CACHEINFO, sizeof(ci), &ci))
532 goto nla_put_failure;
534 if (nla_put(skb, NDA_VLAN, sizeof(u16), &fdb->vlan_id))
535 goto nla_put_failure;
537 return nlmsg_end(skb, nlh);
540 nlmsg_cancel(skb, nlh);
544 static inline size_t fdb_nlmsg_size(void)
546 return NLMSG_ALIGN(sizeof(struct ndmsg))
547 + nla_total_size(ETH_ALEN) /* NDA_LLADDR */
548 + nla_total_size(sizeof(u16)) /* NDA_VLAN */
549 + nla_total_size(sizeof(struct nda_cacheinfo));
552 static void fdb_notify(struct net_bridge *br,
553 const struct net_bridge_fdb_entry *fdb, int type)
555 struct net *net = dev_net(br->dev);
559 skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
563 err = fdb_fill_info(skb, br, fdb, 0, 0, type, 0);
565 /* -EMSGSIZE implies BUG in fdb_nlmsg_size() */
566 WARN_ON(err == -EMSGSIZE);
570 rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
574 rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
577 /* Dump information about entries, in response to GETNEIGH */
578 int br_fdb_dump(struct sk_buff *skb,
579 struct netlink_callback *cb,
580 struct net_device *dev,
583 struct net_bridge *br = netdev_priv(dev);
586 if (!(dev->priv_flags & IFF_EBRIDGE))
589 for (i = 0; i < BR_HASH_SIZE; i++) {
590 struct net_bridge_fdb_entry *f;
592 hlist_for_each_entry_rcu(f, &br->hash[i], hlist) {
593 if (idx < cb->args[0])
596 if (fdb_fill_info(skb, br, f,
597 NETLINK_CB(cb->skb).portid,
611 /* Update (create or replace) forwarding database entry */
612 static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr,
613 __u16 state, __u16 flags, __u16 vid)
615 struct net_bridge *br = source->br;
616 struct hlist_head *head = &br->hash[br_mac_hash(addr, vid)];
617 struct net_bridge_fdb_entry *fdb;
618 bool modified = false;
620 fdb = fdb_find(head, addr, vid);
622 if (!(flags & NLM_F_CREATE))
625 fdb = fdb_create(head, source, addr, vid);
631 if (flags & NLM_F_EXCL)
634 if (fdb->dst != source) {
640 if (fdb_to_nud(fdb) != state) {
641 if (state & NUD_PERMANENT)
642 fdb->is_local = fdb->is_static = 1;
643 else if (state & NUD_NOARP) {
647 fdb->is_local = fdb->is_static = 0;
654 fdb->updated = jiffies;
655 fdb_notify(br, fdb, RTM_NEWNEIGH);
661 static int __br_fdb_add(struct ndmsg *ndm, struct net_bridge_port *p,
662 const unsigned char *addr, u16 nlh_flags, u16 vid)
666 if (ndm->ndm_flags & NTF_USE) {
668 br_fdb_update(p->br, p, addr, vid);
671 spin_lock_bh(&p->br->hash_lock);
672 err = fdb_add_entry(p, addr, ndm->ndm_state,
674 spin_unlock_bh(&p->br->hash_lock);
680 /* Add new permanent fdb entry with RTM_NEWNEIGH */
681 int br_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
682 struct net_device *dev,
683 const unsigned char *addr, u16 nlh_flags)
685 struct net_bridge_port *p;
687 struct net_port_vlans *pv;
688 unsigned short vid = VLAN_N_VID;
690 if (!(ndm->ndm_state & (NUD_PERMANENT|NUD_NOARP|NUD_REACHABLE))) {
691 pr_info("bridge: RTM_NEWNEIGH with invalid state %#x\n", ndm->ndm_state);
696 if (nla_len(tb[NDA_VLAN]) != sizeof(unsigned short)) {
697 pr_info("bridge: RTM_NEWNEIGH with invalid vlan\n");
701 vid = nla_get_u16(tb[NDA_VLAN]);
703 if (!vid || vid >= VLAN_VID_MASK) {
704 pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
710 if (is_zero_ether_addr(addr)) {
711 pr_info("bridge: RTM_NEWNEIGH with invalid ether address\n");
715 p = br_port_get_rtnl(dev);
717 pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n",
722 pv = nbp_get_vlan_info(p);
723 if (vid != VLAN_N_VID) {
724 if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
725 pr_info("bridge: RTM_NEWNEIGH with unconfigured "
726 "vlan %d on port %s\n", vid, dev->name);
730 /* VID was specified, so use it. */
731 err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
733 if (!pv || bitmap_empty(pv->vlan_bitmap, VLAN_N_VID)) {
734 err = __br_fdb_add(ndm, p, addr, nlh_flags, 0);
738 /* We have vlans configured on this port and user didn't
739 * specify a VLAN. To be nice, add/update entry for every
742 for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
743 err = __br_fdb_add(ndm, p, addr, nlh_flags, vid);
753 int fdb_delete_by_addr(struct net_bridge *br, const u8 *addr,
756 struct hlist_head *head = &br->hash[br_mac_hash(addr, vlan)];
757 struct net_bridge_fdb_entry *fdb;
759 fdb = fdb_find(head, addr, vlan);
767 static int __br_fdb_delete(struct net_bridge_port *p,
768 const unsigned char *addr, u16 vid)
772 spin_lock_bh(&p->br->hash_lock);
773 err = fdb_delete_by_addr(p->br, addr, vid);
774 spin_unlock_bh(&p->br->hash_lock);
779 /* Remove neighbor entry with RTM_DELNEIGH */
780 int br_fdb_delete(struct ndmsg *ndm, struct nlattr *tb[],
781 struct net_device *dev,
782 const unsigned char *addr)
784 struct net_bridge_port *p;
786 struct net_port_vlans *pv;
787 unsigned short vid = VLAN_N_VID;
790 if (nla_len(tb[NDA_VLAN]) != sizeof(unsigned short)) {
791 pr_info("bridge: RTM_NEWNEIGH with invalid vlan\n");
795 vid = nla_get_u16(tb[NDA_VLAN]);
797 if (!vid || vid >= VLAN_VID_MASK) {
798 pr_info("bridge: RTM_NEWNEIGH with invalid vlan id %d\n",
803 p = br_port_get_rtnl(dev);
805 pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n",
810 pv = nbp_get_vlan_info(p);
811 if (vid != VLAN_N_VID) {
812 if (!pv || !test_bit(vid, pv->vlan_bitmap)) {
813 pr_info("bridge: RTM_DELNEIGH with unconfigured "
814 "vlan %d on port %s\n", vid, dev->name);
818 err = __br_fdb_delete(p, addr, vid);
820 if (!pv || bitmap_empty(pv->vlan_bitmap, VLAN_N_VID)) {
821 err = __br_fdb_delete(p, addr, 0);
825 /* We have vlans configured on this port and user didn't
826 * specify a VLAN. To be nice, add/update entry for every
830 for_each_set_bit(vid, pv->vlan_bitmap, VLAN_N_VID) {
831 err &= __br_fdb_delete(p, addr, vid);