369 lines
8.6 KiB
C
369 lines
8.6 KiB
C
/*
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* Forwarding database
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* Linux ethernet bridge
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*
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* Authors:
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* Lennert Buytenhek <buytenh@gnu.org>
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*
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* $Id: br_fdb.c,v 1.6 2002/01/17 00:57:07 davem Exp $
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/times.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/jhash.h>
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#include <asm/atomic.h>
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#include "br_private.h"
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static kmem_cache_t *br_fdb_cache __read_mostly;
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static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
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const unsigned char *addr);
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void __init br_fdb_init(void)
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{
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br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
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sizeof(struct net_bridge_fdb_entry),
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0,
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SLAB_HWCACHE_ALIGN, NULL, NULL);
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}
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void __exit br_fdb_fini(void)
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{
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kmem_cache_destroy(br_fdb_cache);
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}
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/* if topology_changing then use forward_delay (default 15 sec)
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* otherwise keep longer (default 5 minutes)
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*/
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static __inline__ unsigned long hold_time(const struct net_bridge *br)
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{
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return br->topology_change ? br->forward_delay : br->ageing_time;
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}
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static __inline__ int has_expired(const struct net_bridge *br,
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const struct net_bridge_fdb_entry *fdb)
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{
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return !fdb->is_static
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&& time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
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}
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static __inline__ int br_mac_hash(const unsigned char *mac)
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{
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return jhash(mac, ETH_ALEN, 0) & (BR_HASH_SIZE - 1);
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}
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static __inline__ void fdb_delete(struct net_bridge_fdb_entry *f)
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{
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hlist_del_rcu(&f->hlist);
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br_fdb_put(f);
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}
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void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
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{
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struct net_bridge *br = p->br;
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int i;
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spin_lock_bh(&br->hash_lock);
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/* Search all chains since old address/hash is unknown */
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for (i = 0; i < BR_HASH_SIZE; i++) {
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struct hlist_node *h;
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hlist_for_each(h, &br->hash[i]) {
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struct net_bridge_fdb_entry *f;
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f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
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if (f->dst == p && f->is_local) {
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/* maybe another port has same hw addr? */
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struct net_bridge_port *op;
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list_for_each_entry(op, &br->port_list, list) {
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if (op != p &&
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!compare_ether_addr(op->dev->dev_addr,
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f->addr.addr)) {
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f->dst = op;
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goto insert;
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}
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}
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/* delete old one */
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fdb_delete(f);
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goto insert;
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}
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}
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}
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insert:
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/* insert new address, may fail if invalid address or dup. */
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fdb_insert(br, p, newaddr);
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spin_unlock_bh(&br->hash_lock);
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}
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void br_fdb_cleanup(unsigned long _data)
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{
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struct net_bridge *br = (struct net_bridge *)_data;
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unsigned long delay = hold_time(br);
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int i;
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spin_lock_bh(&br->hash_lock);
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for (i = 0; i < BR_HASH_SIZE; i++) {
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struct net_bridge_fdb_entry *f;
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struct hlist_node *h, *n;
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hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
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if (!f->is_static &&
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time_before_eq(f->ageing_timer + delay, jiffies))
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fdb_delete(f);
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}
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}
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spin_unlock_bh(&br->hash_lock);
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mod_timer(&br->gc_timer, jiffies + HZ/10);
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}
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void br_fdb_delete_by_port(struct net_bridge *br, struct net_bridge_port *p)
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{
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int i;
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spin_lock_bh(&br->hash_lock);
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for (i = 0; i < BR_HASH_SIZE; i++) {
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struct hlist_node *h, *g;
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hlist_for_each_safe(h, g, &br->hash[i]) {
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struct net_bridge_fdb_entry *f
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= hlist_entry(h, struct net_bridge_fdb_entry, hlist);
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if (f->dst != p)
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continue;
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/*
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* if multiple ports all have the same device address
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* then when one port is deleted, assign
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* the local entry to other port
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*/
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if (f->is_local) {
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struct net_bridge_port *op;
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list_for_each_entry(op, &br->port_list, list) {
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if (op != p &&
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!compare_ether_addr(op->dev->dev_addr,
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f->addr.addr)) {
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f->dst = op;
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goto skip_delete;
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}
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}
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}
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fdb_delete(f);
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skip_delete: ;
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}
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}
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spin_unlock_bh(&br->hash_lock);
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}
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/* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
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struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
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const unsigned char *addr)
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{
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struct hlist_node *h;
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struct net_bridge_fdb_entry *fdb;
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hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
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if (!compare_ether_addr(fdb->addr.addr, addr)) {
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if (unlikely(has_expired(br, fdb)))
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break;
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return fdb;
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}
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}
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return NULL;
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}
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/* Interface used by ATM hook that keeps a ref count */
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struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br,
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unsigned char *addr)
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{
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struct net_bridge_fdb_entry *fdb;
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rcu_read_lock();
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fdb = __br_fdb_get(br, addr);
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if (fdb)
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atomic_inc(&fdb->use_count);
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rcu_read_unlock();
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return fdb;
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}
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static void fdb_rcu_free(struct rcu_head *head)
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{
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struct net_bridge_fdb_entry *ent
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= container_of(head, struct net_bridge_fdb_entry, rcu);
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kmem_cache_free(br_fdb_cache, ent);
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}
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/* Set entry up for deletion with RCU */
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void br_fdb_put(struct net_bridge_fdb_entry *ent)
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{
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if (atomic_dec_and_test(&ent->use_count))
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call_rcu(&ent->rcu, fdb_rcu_free);
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}
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/*
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* Fill buffer with forwarding table records in
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* the API format.
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*/
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int br_fdb_fillbuf(struct net_bridge *br, void *buf,
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unsigned long maxnum, unsigned long skip)
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{
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struct __fdb_entry *fe = buf;
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int i, num = 0;
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struct hlist_node *h;
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struct net_bridge_fdb_entry *f;
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memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
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rcu_read_lock();
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for (i = 0; i < BR_HASH_SIZE; i++) {
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hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
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if (num >= maxnum)
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goto out;
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if (has_expired(br, f))
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continue;
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if (skip) {
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--skip;
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continue;
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}
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/* convert from internal format to API */
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memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
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fe->port_no = f->dst->port_no;
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fe->is_local = f->is_local;
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if (!f->is_static)
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fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
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++fe;
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++num;
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}
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}
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out:
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rcu_read_unlock();
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return num;
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}
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static inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
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const unsigned char *addr)
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{
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struct hlist_node *h;
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struct net_bridge_fdb_entry *fdb;
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hlist_for_each_entry_rcu(fdb, h, head, hlist) {
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if (!compare_ether_addr(fdb->addr.addr, addr))
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return fdb;
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}
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return NULL;
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}
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static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
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struct net_bridge_port *source,
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const unsigned char *addr,
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int is_local)
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{
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struct net_bridge_fdb_entry *fdb;
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fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
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if (fdb) {
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memcpy(fdb->addr.addr, addr, ETH_ALEN);
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atomic_set(&fdb->use_count, 1);
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hlist_add_head_rcu(&fdb->hlist, head);
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fdb->dst = source;
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fdb->is_local = is_local;
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fdb->is_static = is_local;
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fdb->ageing_timer = jiffies;
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}
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return fdb;
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}
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static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
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const unsigned char *addr)
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{
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struct hlist_head *head = &br->hash[br_mac_hash(addr)];
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struct net_bridge_fdb_entry *fdb;
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if (!is_valid_ether_addr(addr))
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return -EINVAL;
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fdb = fdb_find(head, addr);
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if (fdb) {
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/* it is okay to have multiple ports with same
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* address, just use the first one.
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*/
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if (fdb->is_local)
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return 0;
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printk(KERN_WARNING "%s adding interface with same address "
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"as a received packet\n",
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source->dev->name);
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fdb_delete(fdb);
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}
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if (!fdb_create(head, source, addr, 1))
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return -ENOMEM;
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return 0;
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}
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int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
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const unsigned char *addr)
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{
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int ret;
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spin_lock_bh(&br->hash_lock);
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ret = fdb_insert(br, source, addr);
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spin_unlock_bh(&br->hash_lock);
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return ret;
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}
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void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
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const unsigned char *addr)
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{
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struct hlist_head *head = &br->hash[br_mac_hash(addr)];
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struct net_bridge_fdb_entry *fdb;
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/* some users want to always flood. */
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if (hold_time(br) == 0)
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return;
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rcu_read_lock();
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fdb = fdb_find(head, addr);
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if (likely(fdb)) {
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/* attempt to update an entry for a local interface */
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if (unlikely(fdb->is_local)) {
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if (net_ratelimit())
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printk(KERN_WARNING "%s: received packet with "
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" own address as source address\n",
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source->dev->name);
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} else {
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/* fastpath: update of existing entry */
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fdb->dst = source;
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fdb->ageing_timer = jiffies;
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}
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} else {
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spin_lock_bh(&br->hash_lock);
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if (!fdb_find(head, addr))
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fdb_create(head, source, addr, 0);
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/* else we lose race and someone else inserts
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* it first, don't bother updating
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*/
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spin_unlock_bh(&br->hash_lock);
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}
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rcu_read_unlock();
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}
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