[POWERPC] mpic_u3msi: Failed allocation unnoticed

[linux-2.6/next.git] / net / bridge / br_fdb.c

/*
 *      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 <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);
        }
}