/*
   *	Userspace interface
   *	Linux ethernet bridge
   *
   *	Authors:
   *	Lennert Buytenhek		<buytenh@gnu.org>
   *
   *	$Id: br_if.c,v 1.7 2001/12/24 00:59:55 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/netdevice.h>
  #include <linux/ethtool.h>
  #include <linux/if_arp.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/rtnetlink.h>

  #include <linux/if_ether.h>

  #include <net/sock.h>
  
  #include "br_private.h"
  
  /*
   * Determine initial path cost based on speed.
   * using recommendations from 802.1d standard
   *
   * Need to simulate user ioctl because not all device's that support
   * ethtool, use ethtool_ops.  Also, since driver might sleep need to
   * not be holding any locks.
   */

  static int port_cost(struct net_device *dev)

  {

  	struct ethtool_cmd ecmd = { ETHTOOL_GSET };
  	struct ifreq ifr;
  	mm_segment_t old_fs;
  	int err;
  
  	strncpy(ifr.ifr_name, dev->name, IFNAMSIZ);
  	ifr.ifr_data = (void __user *) &ecmd;
  
  	old_fs = get_fs();
  	set_fs(KERNEL_DS);
  	err = dev_ethtool(&ifr);
  	set_fs(old_fs);
  	
  	if (!err) {
  		switch(ecmd.speed) {
  		case SPEED_100:
  			return 19;
  		case SPEED_1000:
  			return 4;
  		case SPEED_10000:
  			return 2;
  		case SPEED_10:
  			return 100;

  		}
  	}
  
  	/* Old silly heuristics based on name */
  	if (!strncmp(dev->name, "lec", 3))
  		return 7;
  
  	if (!strncmp(dev->name, "plip", 4))
  		return 2500;
  
  	return 100;	/* assume old 10Mbps */
  }

  
  /*
   * Check for port carrier transistions.
   * Called from work queue to allow for calling functions that
   * might sleep (such as speed check), and to debounce.
   */
  static void port_carrier_check(void *arg)
  {
  	struct net_bridge_port *p = arg;
  
  	rtnl_lock();
  	if (netif_carrier_ok(p->dev)) {
  		u32 cost = port_cost(p->dev);
  
  		spin_lock_bh(&p->br->lock);
  		if (p->state == BR_STATE_DISABLED) {
  			p->path_cost = cost;
  			br_stp_enable_port(p);
  		}
  		spin_unlock_bh(&p->br->lock);
  	} else {
  		spin_lock_bh(&p->br->lock);
  		if (p->state != BR_STATE_DISABLED)
  			br_stp_disable_port(p);
  		spin_unlock_bh(&p->br->lock);
  	}
  	rtnl_unlock();
  }

  static void destroy_nbp(struct net_bridge_port *p)
  {
  	struct net_device *dev = p->dev;

  	p->br = NULL;
  	p->dev = NULL;
  	dev_put(dev);
  
  	br_sysfs_freeif(p);
  }
  
  static void destroy_nbp_rcu(struct rcu_head *head)
  {
  	struct net_bridge_port *p =
  			container_of(head, struct net_bridge_port, rcu);
  	destroy_nbp(p);
  }
  
  /* called with RTNL */
  static void del_nbp(struct net_bridge_port *p)
  {
  	struct net_bridge *br = p->br;
  	struct net_device *dev = p->dev;

  	dev->br_port = NULL;

  	dev_set_promiscuity(dev, -1);

  	cancel_delayed_work(&p->carrier_check);
  	flush_scheduled_work();

  	spin_lock_bh(&br->lock);
  	br_stp_disable_port(p);
  	spin_unlock_bh(&br->lock);
  
  	br_fdb_delete_by_port(br, p);
  
  	list_del_rcu(&p->list);
  
  	del_timer_sync(&p->message_age_timer);
  	del_timer_sync(&p->forward_delay_timer);
  	del_timer_sync(&p->hold_timer);
  	
  	call_rcu(&p->rcu, destroy_nbp_rcu);
  }
  
  /* called with RTNL */
  static void del_br(struct net_bridge *br)
  {
  	struct net_bridge_port *p, *n;
  
  	list_for_each_entry_safe(p, n, &br->port_list, list) {
  		br_sysfs_removeif(p);
  		del_nbp(p);
  	}
  
  	del_timer_sync(&br->gc_timer);
  
  	br_sysfs_delbr(br->dev);
   	unregister_netdevice(br->dev);
  }
  
  static struct net_device *new_bridge_dev(const char *name)
  {
  	struct net_bridge *br;
  	struct net_device *dev;
  
  	dev = alloc_netdev(sizeof(struct net_bridge), name,
  			   br_dev_setup);
  	
  	if (!dev)
  		return NULL;
  
  	br = netdev_priv(dev);
  	br->dev = dev;
  
  	spin_lock_init(&br->lock);
  	INIT_LIST_HEAD(&br->port_list);
  	spin_lock_init(&br->hash_lock);
  
  	br->bridge_id.prio[0] = 0x80;
  	br->bridge_id.prio[1] = 0x00;
  	memset(br->bridge_id.addr, 0, ETH_ALEN);

  	br->feature_mask = dev->features;

  	br->stp_enabled = 0;
  	br->designated_root = br->bridge_id;
  	br->root_path_cost = 0;
  	br->root_port = 0;
  	br->bridge_max_age = br->max_age = 20 * HZ;
  	br->bridge_hello_time = br->hello_time = 2 * HZ;
  	br->bridge_forward_delay = br->forward_delay = 15 * HZ;
  	br->topology_change = 0;
  	br->topology_change_detected = 0;
  	br->ageing_time = 300 * HZ;
  	INIT_LIST_HEAD(&br->age_list);
  
  	br_stp_timer_init(br);
  
  	return dev;
  }
  
  /* find an available port number */
  static int find_portno(struct net_bridge *br)
  {
  	int index;
  	struct net_bridge_port *p;
  	unsigned long *inuse;
  
  	inuse = kmalloc(BITS_TO_LONGS(BR_MAX_PORTS)*sizeof(unsigned long),
  			GFP_KERNEL);
  	if (!inuse)
  		return -ENOMEM;
  
  	memset(inuse, 0, BITS_TO_LONGS(BR_MAX_PORTS)*sizeof(unsigned long));
  	set_bit(0, inuse);	/* zero is reserved */
  	list_for_each_entry(p, &br->port_list, list) {
  		set_bit(p->port_no, inuse);
  	}
  	index = find_first_zero_bit(inuse, BR_MAX_PORTS);
  	kfree(inuse);
  
  	return (index >= BR_MAX_PORTS) ? -EXFULL : index;
  }

  /* called with RTNL but without bridge lock */

  static struct net_bridge_port *new_nbp(struct net_bridge *br, 

  				       struct net_device *dev)

  {
  	int index;
  	struct net_bridge_port *p;
  	
  	index = find_portno(br);
  	if (index < 0)
  		return ERR_PTR(index);
  
  	p = kmalloc(sizeof(*p), GFP_KERNEL);
  	if (p == NULL)
  		return ERR_PTR(-ENOMEM);
  
  	memset(p, 0, sizeof(*p));
  	p->br = br;
  	dev_hold(dev);
  	p->dev = dev;

  	p->path_cost = port_cost(dev);

   	p->priority = 0x8000 >> BR_PORT_BITS;
  	dev->br_port = p;
  	p->port_no = index;
  	br_init_port(p);
  	p->state = BR_STATE_DISABLED;

  	INIT_WORK(&p->carrier_check, port_carrier_check, p);

  	kobject_init(&p->kobj);
  
  	return p;
  }
  
  int br_add_bridge(const char *name)
  {
  	struct net_device *dev;
  	int ret;
  
  	dev = new_bridge_dev(name);
  	if (!dev) 
  		return -ENOMEM;
  
  	rtnl_lock();
  	if (strchr(dev->name, '%')) {
  		ret = dev_alloc_name(dev, dev->name);
  		if (ret < 0)
  			goto err1;
  	}
  
  	ret = register_netdevice(dev);
  	if (ret)
  		goto err2;
  
  	/* network device kobject is not setup until
  	 * after rtnl_unlock does it's hotplug magic.
  	 * so hold reference to avoid race.
  	 */
  	dev_hold(dev);
  	rtnl_unlock();
  
  	ret = br_sysfs_addbr(dev);
  	dev_put(dev);
  
  	if (ret) 
  		unregister_netdev(dev);
   out:
  	return ret;
  
   err2:
  	free_netdev(dev);
   err1:
  	rtnl_unlock();
  	goto out;
  }
  
  int br_del_bridge(const char *name)
  {
  	struct net_device *dev;
  	int ret = 0;
  
  	rtnl_lock();
  	dev = __dev_get_by_name(name);
  	if (dev == NULL) 
  		ret =  -ENXIO; 	/* Could not find device */
  
  	else if (!(dev->priv_flags & IFF_EBRIDGE)) {
  		/* Attempt to delete non bridge device! */
  		ret = -EPERM;
  	}
  
  	else if (dev->flags & IFF_UP) {
  		/* Not shutdown yet. */
  		ret = -EBUSY;
  	} 
  
  	else 
  		del_br(netdev_priv(dev));
  
  	rtnl_unlock();
  	return ret;
  }

  /* MTU of the bridge pseudo-device: ETH_DATA_LEN or the minimum of the ports */

  int br_min_mtu(const struct net_bridge *br)
  {
  	const struct net_bridge_port *p;
  	int mtu = 0;
  
  	ASSERT_RTNL();
  
  	if (list_empty(&br->port_list))

  		mtu = ETH_DATA_LEN;

  	else {
  		list_for_each_entry(p, &br->port_list, list) {
  			if (!mtu  || p->dev->mtu < mtu)
  				mtu = p->dev->mtu;
  		}
  	}
  	return mtu;
  }

  /*
   * Recomputes features using slave's features
   */
  void br_features_recompute(struct net_bridge *br)
  {
  	struct net_bridge_port *p;
  	unsigned long features, checksum;

  	features = br->feature_mask &~ NETIF_F_IP_CSUM;
  	checksum = br->feature_mask & NETIF_F_IP_CSUM;

  
  	list_for_each_entry(p, &br->port_list, list) {
  		if (!(p->dev->features 
  		      & (NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM)))
  			checksum = 0;
  		features &= p->dev->features;
  	}
  
  	br->dev->features = features | checksum | NETIF_F_LLTX;
  }

  /* called with RTNL */
  int br_add_if(struct net_bridge *br, struct net_device *dev)
  {
  	struct net_bridge_port *p;
  	int err = 0;
  
  	if (dev->flags & IFF_LOOPBACK || dev->type != ARPHRD_ETHER)
  		return -EINVAL;
  
  	if (dev->hard_start_xmit == br_dev_xmit)
  		return -ELOOP;
  
  	if (dev->br_port != NULL)
  		return -EBUSY;

  	if (IS_ERR(p = new_nbp(br, dev)))

  		return PTR_ERR(p);
  
   	if ((err = br_fdb_insert(br, p, dev->dev_addr)))
  		destroy_nbp(p);
   
  	else if ((err = br_sysfs_addif(p)))
  		del_nbp(p);
  	else {
  		dev_set_promiscuity(dev, 1);
  
  		list_add_rcu(&p->list, &br->port_list);
  
  		spin_lock_bh(&br->lock);
  		br_stp_recalculate_bridge_id(br);

  		br_features_recompute(br);

  		if ((br->dev->flags & IFF_UP) 
  		    && (dev->flags & IFF_UP) && netif_carrier_ok(dev))
  			br_stp_enable_port(p);
  		spin_unlock_bh(&br->lock);
  
  		dev_set_mtu(br->dev, br_min_mtu(br));
  	}
  
  	return err;
  }
  
  /* called with RTNL */
  int br_del_if(struct net_bridge *br, struct net_device *dev)
  {
  	struct net_bridge_port *p = dev->br_port;
  	
  	if (!p || p->br != br) 
  		return -EINVAL;
  
  	br_sysfs_removeif(p);
  	del_nbp(p);
  
  	spin_lock_bh(&br->lock);
  	br_stp_recalculate_bridge_id(br);

  	br_features_recompute(br);

  	spin_unlock_bh(&br->lock);
  
  	return 0;
  }
  
  void __exit br_cleanup_bridges(void)
  {
  	struct net_device *dev, *nxt;
  
  	rtnl_lock();
  	for (dev = dev_base; dev; dev = nxt) {
  		nxt = dev->next;
  		if (dev->priv_flags & IFF_EBRIDGE)
  			del_br(dev->priv);
  	}
  	rtnl_unlock();
  
  }