net/bridge/br_fdb.c - pub/scm/linux/kernel/git/joro/linux - Git at Google

 /*
  *	Forwarding database
  *	Linux ethernet bridge
  *
  *	Authors:
  *	Lennert Buytenhek		<buytenh@gnu.org>
  *
  *	$Id: br_fdb.c,v 1.6 2002/01/17 00:57:07 davem Exp $
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License
  *	as published by the Free Software Foundation; either version
  *	2 of the License, or (at your option) any later version.
  */

 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/spinlock.h>
 #include <linux/times.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <asm/atomic.h>
 #include "br_private.h"

 static kmem_cache_t *br_fdb_cache;
 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
 		      const unsigned char *addr, int is_local);

 void __init br_fdb_init(void)
 {
 	br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
 					 sizeof(struct net_bridge_fdb_entry),
 					 0,
 					 SLAB_HWCACHE_ALIGN, NULL, NULL);
 }

 void __exit br_fdb_fini(void)
 {
 	kmem_cache_destroy(br_fdb_cache);
 }


 /* if topology_changing then use forward_delay (default 15 sec)
  * otherwise keep longer (default 5 minutes)
  */
 static __inline__ unsigned long hold_time(const struct net_bridge *br)
 {
 	return br->topology_change ? br->forward_delay : br->ageing_time;
 }

 static __inline__ int has_expired(const struct net_bridge *br,
 				  const struct net_bridge_fdb_entry *fdb)
 {
 	return !fdb->is_static
 		&& time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
 }

 static __inline__ int br_mac_hash(const unsigned char *mac)
 {
 	unsigned long x;

 	x = mac[0];
 	x = (x << 2) ^ mac[1];
 	x = (x << 2) ^ mac[2];
 	x = (x << 2) ^ mac[3];
 	x = (x << 2) ^ mac[4];
 	x = (x << 2) ^ mac[5];

 	x ^= x >> 8;

 	return x & (BR_HASH_SIZE - 1);
 }

 static __inline__ void fdb_delete(struct net_bridge_fdb_entry *f)
 {
 	hlist_del(&f->hlist);
 	if (!f->is_static)
 		list_del(&f->age_list);

 	br_fdb_put(f);
 }

 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
 {
 	struct net_bridge *br = p->br;
 	int i;

 	write_lock_bh(&br->hash_lock);

 	/* Search all chains since old address/hash is unknown */
 	for (i = 0; i < BR_HASH_SIZE; i++) {
 		struct hlist_node *h;
 		hlist_for_each(h, &br->hash[i]) {
 			struct net_bridge_fdb_entry *f;

 			f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
 			if (f->dst == p && f->is_local) {
 				/* maybe another port has same hw addr? */
 				struct net_bridge_port *op;
 				list_for_each_entry(op, &br->port_list, list) {
 					if (op != p &&
 					    !memcmp(op->dev->dev_addr,
 						    f->addr.addr, ETH_ALEN)) {
 						f->dst = op;
 						goto insert;
 					}
 				}

 				/* delete old one */
 				fdb_delete(f);
 				goto insert;
 			}
 		}
 	}
  insert:
 	/* insert new address,  may fail if invalid address or dup. */
 	fdb_insert(br, p, newaddr, 1);


 	write_unlock_bh(&br->hash_lock);
 }

 void br_fdb_cleanup(unsigned long _data)
 {
 	struct net_bridge *br = (struct net_bridge *)_data;
 	struct list_head *l, *n;
 	unsigned long delay;

 	write_lock_bh(&br->hash_lock);
 	delay = hold_time(br);

 	list_for_each_safe(l, n, &br->age_list) {
 		struct net_bridge_fdb_entry *f
 			= list_entry(l, struct net_bridge_fdb_entry, age_list);
 		unsigned long expires = f->ageing_timer + delay;

 		if (time_before_eq(expires, jiffies)) {
 			WARN_ON(f->is_static);
 			pr_debug("expire age %lu jiffies %lu\n",
 				 f->ageing_timer, jiffies);
 			fdb_delete(f);
 		} else {
 			mod_timer(&br->gc_timer, expires);
 			break;
 		}
 	}
 	write_unlock_bh(&br->hash_lock);
 }

 void br_fdb_delete_by_port(struct net_bridge *br, struct net_bridge_port *p)
 {
 	int i;

 	write_lock_bh(&br->hash_lock);
 	for (i = 0; i < BR_HASH_SIZE; i++) {
 		struct hlist_node *h, *g;

 		hlist_for_each_safe(h, g, &br->hash[i]) {
 			struct net_bridge_fdb_entry *f
 				= hlist_entry(h, struct net_bridge_fdb_entry, hlist);
 			if (f->dst != p)
 				continue;

 			/*
 			 * if multiple ports all have the same device address
 			 * then when one port is deleted, assign
 			 * the local entry to other port
 			 */
 			if (f->is_local) {
 				struct net_bridge_port *op;
 				list_for_each_entry(op, &br->port_list, list) {
 					if (op != p &&
 					    !memcmp(op->dev->dev_addr,
 						    f->addr.addr, ETH_ALEN)) {
 						f->dst = op;
 						goto skip_delete;
 					}
 				}
 			}

 			fdb_delete(f);
 		skip_delete: ;
 		}
 	}
 	write_unlock_bh(&br->hash_lock);
 }

 struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br, unsigned char *addr)
 {
 	struct hlist_node *h;

 	read_lock_bh(&br->hash_lock);

 	hlist_for_each(h, &br->hash[br_mac_hash(addr)]) {
 		struct net_bridge_fdb_entry *fdb
 			= hlist_entry(h, struct net_bridge_fdb_entry, hlist);

 		if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
 			if (has_expired(br, fdb))
 				goto ret_null;

 			atomic_inc(&fdb->use_count);
 			read_unlock_bh(&br->hash_lock);
 			return fdb;
 		}
 	}
  ret_null:
 	read_unlock_bh(&br->hash_lock);
 	return NULL;
 }

 void br_fdb_put(struct net_bridge_fdb_entry *ent)
 {
 	if (atomic_dec_and_test(&ent->use_count))
 		kmem_cache_free(br_fdb_cache, ent);
 }

 /*
  * Fill buffer with forwarding table records in
  * the API format.
  */
 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
 		   unsigned long maxnum, unsigned long skip)
 {
 	struct __fdb_entry *fe = buf;
 	int i, num = 0;
 	struct hlist_node *h;
 	struct net_bridge_fdb_entry *f;

 	memset(buf, 0, maxnum*sizeof(struct __fdb_entry));

 	read_lock_bh(&br->hash_lock);
 	for (i = 0; i < BR_HASH_SIZE; i++) {
 		hlist_for_each_entry(f, h, &br->hash[i], hlist) {
 			if (num >= maxnum)
 				goto out;

 			if (has_expired(br, f))
 				continue;

 			if (skip) {
 				--skip;
 				continue;
 			}

 			/* convert from internal format to API */
 			memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
 			fe->port_no = f->dst->port_no;
 			fe->is_local = f->is_local;
 			if (!f->is_static)
 				fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
 			++fe;
 			++num;
 		}
 	}

  out:
 	read_unlock_bh(&br->hash_lock);

 	return num;
 }

 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
 		  const unsigned char *addr, int is_local)
 {
 	struct hlist_node *h;
 	struct net_bridge_fdb_entry *fdb;
 	int hash = br_mac_hash(addr);

 	if (!is_valid_ether_addr(addr))
 		return -EADDRNOTAVAIL;

 	hlist_for_each_entry(fdb, h, &br->hash[hash], hlist) {
 		if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
 			/* attempt to update an entry for a local interface */
 			if (fdb->is_local) {
 				/* it is okay to have multiple ports with same
 				 * address, just don't allow to be spoofed.
 				 */
 				if (is_local)
 					return 0;

 				if (net_ratelimit())
 					printk(KERN_WARNING "%s: received packet with "
 					       " own address as source address\n",
 					       source->dev->name);
 				return -EEXIST;
 			}

 			if (is_local) {
 				printk(KERN_WARNING "%s adding interface with same address "
 				       "as a received packet\n",
 				       source->dev->name);
 				goto update;
 			}

 			if (fdb->is_static)
 				return 0;

 			/* move to end of age list */
 			list_del(&fdb->age_list);
 			goto update;
 		}
 	}

 	fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
 	if (!fdb)
 		return ENOMEM;

 	memcpy(fdb->addr.addr, addr, ETH_ALEN);
 	atomic_set(&fdb->use_count, 1);
 	hlist_add_head(&fdb->hlist, &br->hash[hash]);

 	if (!timer_pending(&br->gc_timer)) {
 		br->gc_timer.expires = jiffies + hold_time(br);
 		add_timer(&br->gc_timer);
 	}

  update:
 	fdb->dst = source;
 	fdb->is_local = is_local;
 	fdb->is_static = is_local;
 	fdb->ageing_timer = jiffies;
 	if (!is_local)
 		list_add_tail(&fdb->age_list, &br->age_list);

 	return 0;
 }

 int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
 		  const unsigned char *addr, int is_local)
 {
 	int ret;

 	write_lock_bh(&br->hash_lock);
 	ret = fdb_insert(br, source, addr, is_local);
 	write_unlock_bh(&br->hash_lock);
 	return ret;
 }
	/*
	* Forwarding database
	* Linux ethernet bridge
	*
	* Authors:
	* Lennert Buytenhek <buytenh@gnu.org>
	*
	* $Id: br_fdb.c,v 1.6 2002/01/17 00:57:07 davem Exp $
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/spinlock.h>
	#include <linux/times.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <asm/atomic.h>
	#include "br_private.h"

	static kmem_cache_t *br_fdb_cache;
	static int fdb_insert(struct net_bridge br, struct net_bridge_port source,
	const unsigned char *addr, int is_local);

	void __init br_fdb_init(void)
	{
	br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
	sizeof(struct net_bridge_fdb_entry),
	0,
	SLAB_HWCACHE_ALIGN, NULL, NULL);
	}

	void __exit br_fdb_fini(void)
	{
	kmem_cache_destroy(br_fdb_cache);
	}


	/* if topology_changing then use forward_delay (default 15 sec)
	* otherwise keep longer (default 5 minutes)
	*/
	static __inline__ unsigned long hold_time(const struct net_bridge *br)
	{
	return br->topology_change ? br->forward_delay : br->ageing_time;
	}

	static __inline__ int has_expired(const struct net_bridge *br,
	const struct net_bridge_fdb_entry *fdb)
	{
	return !fdb->is_static
	&& time_before_eq(fdb->ageing_timer + hold_time(br), jiffies);
	}

	static __inline__ int br_mac_hash(const unsigned char *mac)
	{
	unsigned long x;

	x = mac[0];
	x = (x << 2) ^ mac[1];
	x = (x << 2) ^ mac[2];
	x = (x << 2) ^ mac[3];
	x = (x << 2) ^ mac[4];
	x = (x << 2) ^ mac[5];

	x ^= x >> 8;

	return x & (BR_HASH_SIZE - 1);
	}

	static __inline__ void fdb_delete(struct net_bridge_fdb_entry *f)
	{
	hlist_del(&f->hlist);
	if (!f->is_static)
	list_del(&f->age_list);

	br_fdb_put(f);
	}

	void br_fdb_changeaddr(struct net_bridge_port p, const unsigned char newaddr)
	{
	struct net_bridge *br = p->br;
	int i;

	write_lock_bh(&br->hash_lock);

	/* Search all chains since old address/hash is unknown */
	for (i = 0; i < BR_HASH_SIZE; i++) {
	struct hlist_node *h;
	hlist_for_each(h, &br->hash[i]) {
	struct net_bridge_fdb_entry *f;

	f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
	if (f->dst == p && f->is_local) {
	/* maybe another port has same hw addr? */
	struct net_bridge_port *op;
	list_for_each_entry(op, &br->port_list, list) {
	if (op != p &&
	!memcmp(op->dev->dev_addr,
	f->addr.addr, ETH_ALEN)) {
	f->dst = op;
	goto insert;
	}
	}

	/* delete old one */
	fdb_delete(f);
	goto insert;
	}
	}
	}
	insert:
	/* insert new address, may fail if invalid address or dup. */
	fdb_insert(br, p, newaddr, 1);


	write_unlock_bh(&br->hash_lock);
	}

	void br_fdb_cleanup(unsigned long _data)
	{
	struct net_bridge br = (struct net_bridge )_data;
	struct list_head l, n;
	unsigned long delay;

	write_lock_bh(&br->hash_lock);
	delay = hold_time(br);

	list_for_each_safe(l, n, &br->age_list) {
	struct net_bridge_fdb_entry *f
	= list_entry(l, struct net_bridge_fdb_entry, age_list);
	unsigned long expires = f->ageing_timer + delay;

	if (time_before_eq(expires, jiffies)) {
	WARN_ON(f->is_static);
	pr_debug("expire age %lu jiffies %lu\n",
	f->ageing_timer, jiffies);
	fdb_delete(f);
	} else {
	mod_timer(&br->gc_timer, expires);
	break;
	}
	}
	write_unlock_bh(&br->hash_lock);
	}

	void br_fdb_delete_by_port(struct net_bridge br, struct net_bridge_port p)
	{
	int i;

	write_lock_bh(&br->hash_lock);
	for (i = 0; i < BR_HASH_SIZE; i++) {
	struct hlist_node h, g;

	hlist_for_each_safe(h, g, &br->hash[i]) {
	struct net_bridge_fdb_entry *f
	= hlist_entry(h, struct net_bridge_fdb_entry, hlist);
	if (f->dst != p)
	continue;

	/*
	* if multiple ports all have the same device address
	* then when one port is deleted, assign
	* the local entry to other port
	*/
	if (f->is_local) {
	struct net_bridge_port *op;
	list_for_each_entry(op, &br->port_list, list) {
	if (op != p &&
	!memcmp(op->dev->dev_addr,
	f->addr.addr, ETH_ALEN)) {
	f->dst = op;
	goto skip_delete;
	}
	}
	}

	fdb_delete(f);
	skip_delete: ;
	}
	}
	write_unlock_bh(&br->hash_lock);
	}

	struct net_bridge_fdb_entry br_fdb_get(struct net_bridge br, unsigned char *addr)
	{
	struct hlist_node *h;

	read_lock_bh(&br->hash_lock);

	hlist_for_each(h, &br->hash[br_mac_hash(addr)]) {
	struct net_bridge_fdb_entry *fdb
	= hlist_entry(h, struct net_bridge_fdb_entry, hlist);

	if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
	if (has_expired(br, fdb))
	goto ret_null;

	atomic_inc(&fdb->use_count);
	read_unlock_bh(&br->hash_lock);
	return fdb;
	}
	}
	ret_null:
	read_unlock_bh(&br->hash_lock);
	return NULL;
	}

	void br_fdb_put(struct net_bridge_fdb_entry *ent)
	{
	if (atomic_dec_and_test(&ent->use_count))
	kmem_cache_free(br_fdb_cache, ent);
	}

	/*
	* Fill buffer with forwarding table records in
	* the API format.
	*/
	int br_fdb_fillbuf(struct net_bridge br, void buf,
	unsigned long maxnum, unsigned long skip)
	{
	struct __fdb_entry *fe = buf;
	int i, num = 0;
	struct hlist_node *h;
	struct net_bridge_fdb_entry *f;

	memset(buf, 0, maxnum*sizeof(struct __fdb_entry));

	read_lock_bh(&br->hash_lock);
	for (i = 0; i < BR_HASH_SIZE; i++) {
	hlist_for_each_entry(f, h, &br->hash[i], hlist) {
	if (num >= maxnum)
	goto out;

	if (has_expired(br, f))
	continue;

	if (skip) {
	--skip;
	continue;
	}

	/* convert from internal format to API */
	memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
	fe->port_no = f->dst->port_no;
	fe->is_local = f->is_local;
	if (!f->is_static)
	fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->ageing_timer);
	++fe;
	++num;
	}
	}

	out:
	read_unlock_bh(&br->hash_lock);

	return num;
	}

	static int fdb_insert(struct net_bridge br, struct net_bridge_port source,
	const unsigned char *addr, int is_local)
	{
	struct hlist_node *h;
	struct net_bridge_fdb_entry *fdb;
	int hash = br_mac_hash(addr);

	if (!is_valid_ether_addr(addr))
	return -EADDRNOTAVAIL;

	hlist_for_each_entry(fdb, h, &br->hash[hash], hlist) {
	if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
	/* attempt to update an entry for a local interface */
	if (fdb->is_local) {
	/* it is okay to have multiple ports with same
	* address, just don't allow to be spoofed.
	*/
	if (is_local)
	return 0;

	if (net_ratelimit())
	printk(KERN_WARNING "%s: received packet with "
	" own address as source address\n",
	source->dev->name);
	return -EEXIST;
	}

	if (is_local) {
	printk(KERN_WARNING "%s adding interface with same address "
	"as a received packet\n",
	source->dev->name);
	goto update;
	}

	if (fdb->is_static)
	return 0;

	/* move to end of age list */
	list_del(&fdb->age_list);
	goto update;
	}
	}

	fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
	if (!fdb)
	return ENOMEM;

	memcpy(fdb->addr.addr, addr, ETH_ALEN);
	atomic_set(&fdb->use_count, 1);
	hlist_add_head(&fdb->hlist, &br->hash[hash]);

	if (!timer_pending(&br->gc_timer)) {
	br->gc_timer.expires = jiffies + hold_time(br);
	add_timer(&br->gc_timer);
	}

	update:
	fdb->dst = source;
	fdb->is_local = is_local;
	fdb->is_static = is_local;
	fdb->ageing_timer = jiffies;
	if (!is_local)
	list_add_tail(&fdb->age_list, &br->age_list);

	return 0;
	}

	int br_fdb_insert(struct net_bridge br, struct net_bridge_port source,
	const unsigned char *addr, int is_local)
	{
	int ret;

	write_lock_bh(&br->hash_lock);
	ret = fdb_insert(br, source, addr, is_local);
	write_unlock_bh(&br->hash_lock);
	return ret;
	}