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-rw-r--r--net/bridge/br_fdb.c417
1 files changed, 417 insertions, 0 deletions
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
new file mode 100644
index 0000000..a48f5ef
--- /dev/null
+++ b/net/bridge/br_fdb.c
@@ -0,0 +1,417 @@
+/*
+ * Forwarding database
+ * Linux ethernet bridge
+ *
+ * Authors:
+ * Lennert Buytenhek <buytenh@gnu.org>
+ *
+ * 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/rculist.h>
+#include <linux/spinlock.h>
+#include <linux/times.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/jhash.h>
+#include <linux/random.h>
+#include <asm/atomic.h>
+#include <asm/unaligned.h>
+#include "br_private.h"
+
+static struct kmem_cache *br_fdb_cache __read_mostly;
+static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
+ const unsigned char *addr);
+
+static u32 fdb_salt __read_mostly;
+
+int __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);
+ if (!br_fdb_cache)
+ return -ENOMEM;
+
+ get_random_bytes(&fdb_salt, sizeof(fdb_salt));
+ return 0;
+}
+
+void 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)
+{
+ /* use 1 byte of OUI cnd 3 bytes of NIC */
+ u32 key = get_unaligned((u32 *)(mac + 2));
+ return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
+}
+
+static inline void fdb_delete(struct net_bridge_fdb_entry *f)
+{
+ hlist_del_rcu(&f->hlist);
+ 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 &&
+ !compare_ether_addr(op->dev->dev_addr,
+ f->addr.addr)) {
+ 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);
+
+ spin_unlock_bh(&br->hash_lock);
+}
+
+void br_fdb_cleanup(unsigned long _data)
+{
+ struct net_bridge *br = (struct net_bridge *)_data;
+ unsigned long delay = hold_time(br);
+ unsigned long next_timer = jiffies + br->forward_delay;
+ int i;
+
+ spin_lock_bh(&br->hash_lock);
+ for (i = 0; i < BR_HASH_SIZE; i++) {
+ struct net_bridge_fdb_entry *f;
+ struct hlist_node *h, *n;
+
+ hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
+ unsigned long this_timer;
+ if (f->is_static)
+ continue;
+ this_timer = f->ageing_timer + delay;
+ if (time_before_eq(this_timer, jiffies))
+ fdb_delete(f);
+ else if (time_before(this_timer, next_timer))
+ next_timer = this_timer;
+ }
+ }
+ spin_unlock_bh(&br->hash_lock);
+
+ /* Add HZ/4 to ensure we round the jiffies upwards to be after the next
+ * timer, otherwise we might round down and will have no-op run. */
+ mod_timer(&br->gc_timer, round_jiffies(next_timer + HZ/4));
+}
+
+/* Completely flush all dynamic entries in forwarding database.*/
+void br_fdb_flush(struct net_bridge *br)
+{
+ int i;
+
+ spin_lock_bh(&br->hash_lock);
+ for (i = 0; i < BR_HASH_SIZE; i++) {
+ struct net_bridge_fdb_entry *f;
+ struct hlist_node *h, *n;
+ hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
+ if (!f->is_static)
+ fdb_delete(f);
+ }
+ }
+ spin_unlock_bh(&br->hash_lock);
+}
+
+/* Flush all entries refering to a specific port.
+ * if do_all is set also flush static entries
+ */
+void br_fdb_delete_by_port(struct net_bridge *br,
+ const struct net_bridge_port *p,
+ int do_all)
+{
+ 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 (f->is_static && !do_all)
+ 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 &&
+ !compare_ether_addr(op->dev->dev_addr,
+ f->addr.addr)) {
+ 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 (!compare_ether_addr(fdb->addr.addr, addr)) {
+ 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_not_zero(&fdb->use_count))
+ fdb = NULL;
+ 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, 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->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);
+
+ /* due to ABI compat need to split into hi/lo */
+ fe->port_no = f->dst->port_no;
+ fe->port_hi = f->dst->port_no >> 8;
+
+ 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 inline struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
+ const unsigned char *addr)
+{
+ struct hlist_node *h;
+ struct net_bridge_fdb_entry *fdb;
+
+ hlist_for_each_entry_rcu(fdb, h, head, hlist) {
+ if (!compare_ether_addr(fdb->addr.addr, addr))
+ return fdb;
+ }
+ return NULL;
+}
+
+static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
+ struct net_bridge_port *source,
+ const unsigned char *addr,
+ int is_local)
+{
+ struct net_bridge_fdb_entry *fdb;
+
+ fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
+ if (fdb) {
+ memcpy(fdb->addr.addr, addr, ETH_ALEN);
+ atomic_set(&fdb->use_count, 1);
+ hlist_add_head_rcu(&fdb->hlist, head);
+
+ fdb->dst = source;
+ fdb->is_local = is_local;
+ fdb->is_static = is_local;
+ fdb->ageing_timer = jiffies;
+ }
+ return fdb;
+}
+
+static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
+ const unsigned char *addr)
+{
+ struct hlist_head *head = &br->hash[br_mac_hash(addr)];
+ struct net_bridge_fdb_entry *fdb;
+
+ if (!is_valid_ether_addr(addr))
+ return -EINVAL;
+
+ fdb = fdb_find(head, addr);
+ if (fdb) {
+ /* it is okay to have multiple ports with same
+ * address, just use the first one.
+ */
+ if (fdb->is_local)
+ return 0;
+
+ printk(KERN_WARNING "%s adding interface with same address "
+ "as a received packet\n",
+ source->dev->name);
+ fdb_delete(fdb);
+ }
+
+ if (!fdb_create(head, source, addr, 1))
+ return -ENOMEM;
+
+ return 0;
+}
+
+int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
+ const unsigned char *addr)
+{
+ int ret;
+
+ spin_lock_bh(&br->hash_lock);
+ ret = fdb_insert(br, source, addr);
+ spin_unlock_bh(&br->hash_lock);
+ return ret;
+}
+
+void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
+ const unsigned char *addr)
+{
+ struct hlist_head *head = &br->hash[br_mac_hash(addr)];
+ struct net_bridge_fdb_entry *fdb;
+
+ /* some users want to always flood. */
+ if (hold_time(br) == 0)
+ return;
+
+ /* ignore packets unless we are using this port */
+ if (!(source->state == BR_STATE_LEARNING ||
+ source->state == BR_STATE_FORWARDING))
+ return;
+
+ fdb = fdb_find(head, addr);
+ if (likely(fdb)) {
+ /* attempt to update an entry for a local interface */
+ if (unlikely(fdb->is_local)) {
+ if (net_ratelimit())
+ printk(KERN_WARNING "%s: received packet with "
+ " own address as source address\n",
+ source->dev->name);
+ } else {
+ /* fastpath: update of existing entry */
+ fdb->dst = source;
+ fdb->ageing_timer = jiffies;
+ }
+ } else {
+ spin_lock(&br->hash_lock);
+ if (!fdb_find(head, addr))
+ fdb_create(head, source, addr, 0);
+ /* else we lose race and someone else inserts
+ * it first, don't bother updating
+ */
+ spin_unlock(&br->hash_lock);
+ }
+}
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