(2006-08-06) rescue-bootcd

extra/linux-2.6.10/net/bridge/br_fdb.c

@@ -0,0 +1,357 @@
+/*
+ *	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_rcu(&f->hlist);
+	if (!f->is_static)
+		list_del(&f->u.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;
+	
+	spin_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);
+
+
+	spin_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;
+
+	spin_lock_bh(&br->hash_lock);
+	delay = hold_time(br);
+
+	list_for_each_safe(l, n, &br->age_list) {
+		struct net_bridge_fdb_entry *f;
+		unsigned long expires;
+
+		f = list_entry(l, struct net_bridge_fdb_entry, u.age_list);
+		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;
+		}
+	}
+	spin_unlock_bh(&br->hash_lock);
+}
+
+void br_fdb_delete_by_port(struct net_bridge *br, struct net_bridge_port *p)
+{
+	int i;
+
+	spin_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: ;
+		}
+	}
+	spin_unlock_bh(&br->hash_lock);
+}
+
+/* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */
+struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
+					  const unsigned char *addr)
+{
+	struct hlist_node *h;
+	struct net_bridge_fdb_entry *fdb;
+
+	hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
+		if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
+			if (unlikely(has_expired(br, fdb)))
+				break;
+			return fdb;
+		}
+	}
+
+	return NULL;
+}
+
+/* Interface used by ATM hook that keeps a ref count */
+struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br, 
+					unsigned char *addr)
+{
+	struct net_bridge_fdb_entry *fdb;
+
+	rcu_read_lock();
+	fdb = __br_fdb_get(br, addr);
+	if (fdb) 
+		atomic_inc(&fdb->use_count);
+	rcu_read_unlock();
+	return fdb;
+}
+
+static void fdb_rcu_free(struct rcu_head *head)
+{
+	struct net_bridge_fdb_entry *ent
+		= container_of(head, struct net_bridge_fdb_entry, u.rcu);
+	kmem_cache_free(br_fdb_cache, ent);
+}
+
+/* Set entry up for deletion with RCU  */
+void br_fdb_put(struct net_bridge_fdb_entry *ent)
+{
+	if (atomic_dec_and_test(&ent->use_count))
+		call_rcu(&ent->u.rcu, fdb_rcu_free);
+}
+
+/*
+ * 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));
+
+	rcu_read_lock();
+	for (i = 0; i < BR_HASH_SIZE; i++) {
+		hlist_for_each_entry_rcu(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:
+	rcu_read_unlock();
+
+	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->u.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_rcu(&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->u.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;
+
+	spin_lock_bh(&br->hash_lock);
+	ret = fdb_insert(br, source, addr, is_local);
+	spin_unlock_bh(&br->hash_lock);
+	return ret;
+}