/*
   * net/sched/mirred.c	packet mirroring and redirect actions
   *
   *		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.
   *
   * Authors:	Jamal Hadi Salim (2002-4)
   *
   * TODO: Add ingress support (and socket redirect support)
   *
   */

  #include <linux/types.h>
  #include <linux/kernel.h>

  #include <linux/string.h>

  #include <linux/errno.h>

  #include <linux/skbuff.h>
  #include <linux/rtnetlink.h>
  #include <linux/module.h>
  #include <linux/init.h>

  #include <linux/gfp.h>

  #include <net/net_namespace.h>

  #include <net/netlink.h>

  #include <net/pkt_sched.h>
  #include <linux/tc_act/tc_mirred.h>
  #include <net/tc_act/tc_mirred.h>

  #include <linux/if_arp.h>

  #define MIRRED_TAB_MASK     7
  static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  static u32 mirred_idx_gen;

  static DEFINE_RWLOCK(mirred_lock);

  static LIST_HEAD(mirred_list);

  static struct tcf_hashinfo mirred_hash_info = {
  	.htab	=	tcf_mirred_ht,
  	.hmask	=	MIRRED_TAB_MASK,
  	.lock	=	&mirred_lock,
  };

  static int tcf_mirred_release(struct tcf_mirred *m, int bind)

  {

  	if (m) {

  		if (bind)

  			m->tcf_bindcnt--;
  		m->tcf_refcnt--;

  		if (!m->tcf_bindcnt && m->tcf_refcnt <= 0) {

  			list_del(&m->tcfm_list);
  			if (m->tcfm_dev)
  				dev_put(m->tcfm_dev);

  			tcf_hash_destroy(&m->common, &mirred_hash_info);

  			return 1;
  		}
  	}
  	return 0;
  }

  static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  	[TCA_MIRRED_PARMS]	= { .len = sizeof(struct tc_mirred) },
  };

  static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,

  			   struct tc_action *a, int ovr, int bind)

  {

  	struct nlattr *tb[TCA_MIRRED_MAX + 1];

  	struct tc_mirred *parm;

  	struct tcf_mirred *m;
  	struct tcf_common *pc;

  	struct net_device *dev;
  	int ret, ok_push = 0;

  	if (nla == NULL)

  		return -EINVAL;

  	ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  	if (ret < 0)
  		return ret;

  	if (tb[TCA_MIRRED_PARMS] == NULL)

  		return -EINVAL;

  	parm = nla_data(tb[TCA_MIRRED_PARMS]);

  	switch (parm->eaction) {
  	case TCA_EGRESS_MIRROR:
  	case TCA_EGRESS_REDIR:
  		break;
  	default:
  		return -EINVAL;
  	}

  	if (parm->ifindex) {

  		dev = __dev_get_by_index(&init_net, parm->ifindex);

  		if (dev == NULL)
  			return -ENODEV;
  		switch (dev->type) {

  		case ARPHRD_TUNNEL:
  		case ARPHRD_TUNNEL6:
  		case ARPHRD_SIT:
  		case ARPHRD_IPGRE:
  		case ARPHRD_VOID:
  		case ARPHRD_NONE:
  			ok_push = 0;
  			break;
  		default:
  			ok_push = 1;
  			break;

  		}

  	} else {
  		dev = NULL;

  	}

  	pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
  	if (!pc) {

  		if (dev == NULL)

  			return -EINVAL;

  		pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
  				     &mirred_idx_gen, &mirred_hash_info);

  		if (IS_ERR(pc))

  			return PTR_ERR(pc);

  		ret = ACT_P_CREATED;
  	} else {
  		if (!ovr) {

  			tcf_mirred_release(to_mirred(pc), bind);

  			return -EEXIST;
  		}
  	}

  	m = to_mirred(pc);

  	spin_lock_bh(&m->tcf_lock);
  	m->tcf_action = parm->action;
  	m->tcfm_eaction = parm->eaction;

  	if (dev != NULL) {

  		m->tcfm_ifindex = parm->ifindex;

  		if (ret != ACT_P_CREATED)

  			dev_put(m->tcfm_dev);

  		dev_hold(dev);

  		m->tcfm_dev = dev;

  		m->tcfm_ok_push = ok_push;

  	}

  	spin_unlock_bh(&m->tcf_lock);

  	if (ret == ACT_P_CREATED) {
  		list_add(&m->tcfm_list, &mirred_list);

  		tcf_hash_insert(pc, &mirred_hash_info);

  	}

  	return ret;
  }

  static int tcf_mirred_cleanup(struct tc_action *a, int bind)

  {

  	struct tcf_mirred *m = a->priv;

  	if (m)
  		return tcf_mirred_release(m, bind);

  	return 0;
  }

  static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,

  		      struct tcf_result *res)

  {

  	struct tcf_mirred *m = a->priv;

  	struct net_device *dev;

  	struct sk_buff *skb2;
  	u32 at;
  	int retval, err = 1;

  	spin_lock(&m->tcf_lock);

  	m->tcf_tm.lastuse = jiffies;

  	bstats_update(&m->tcf_bstats, skb);

  	dev = m->tcfm_dev;

  	if (!dev) {
  		printk_once(KERN_NOTICE "tc mirred: target device is gone
  ");
  		goto out;
  	}

  	if (!(dev->flags & IFF_UP)) {

  		if (net_ratelimit())

  			pr_notice("tc mirred to Houston: device %s is down
  ",

  				  dev->name);

  		goto out;

  	}

  	at = G_TC_AT(skb->tc_verd);
  	skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);

  	if (skb2 == NULL)

  		goto out;

  	if (!(at & AT_EGRESS)) {

  		if (m->tcfm_ok_push)

  			skb_push(skb2, skb2->dev->hard_header_len);

  	}

  
  	/* mirror is always swallowed */

  	if (m->tcfm_eaction != TCA_EGRESS_MIRROR)

  		skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);

  	skb2->skb_iif = skb->dev->ifindex;

  	skb2->dev = dev;

  	err = dev_queue_xmit(skb2);

  
  out:
  	if (err) {
  		m->tcf_qstats.overlimits++;

  		/* should we be asking for packet to be dropped?
  		 * may make sense for redirect case only
  		 */
  		retval = TC_ACT_SHOT;
  	} else {
  		retval = m->tcf_action;
  	}

  	spin_unlock(&m->tcf_lock);

  
  	return retval;

  }

  static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)

  {

  	unsigned char *b = skb_tail_pointer(skb);

  	struct tcf_mirred *m = a->priv;

  	struct tc_mirred opt = {
  		.index   = m->tcf_index,
  		.action  = m->tcf_action,
  		.refcnt  = m->tcf_refcnt - ref,
  		.bindcnt = m->tcf_bindcnt - bind,
  		.eaction = m->tcfm_eaction,
  		.ifindex = m->tcfm_ifindex,
  	};

  	struct tcf_t t;

  	NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);

  	t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
  	t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
  	t.expires = jiffies_to_clock_t(m->tcf_tm.expires);

  	NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);

  	return skb->len;

  nla_put_failure:

  	nlmsg_trim(skb, b);

  	return -1;
  }

  static int mirred_device_event(struct notifier_block *unused,
  			       unsigned long event, void *ptr)
  {
  	struct net_device *dev = ptr;
  	struct tcf_mirred *m;
  
  	if (event == NETDEV_UNREGISTER)
  		list_for_each_entry(m, &mirred_list, tcfm_list) {
  			if (m->tcfm_dev == dev) {
  				dev_put(dev);
  				m->tcfm_dev = NULL;
  			}
  		}
  
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block mirred_device_notifier = {
  	.notifier_call = mirred_device_event,
  };

  static struct tc_action_ops act_mirred_ops = {
  	.kind		=	"mirred",

  	.hinfo		=	&mirred_hash_info,

  	.type		=	TCA_ACT_MIRRED,
  	.capab		=	TCA_CAP_NONE,
  	.owner		=	THIS_MODULE,
  	.act		=	tcf_mirred,
  	.dump		=	tcf_mirred_dump,
  	.cleanup	=	tcf_mirred_cleanup,
  	.lookup		=	tcf_hash_search,
  	.init		=	tcf_mirred_init,
  	.walk		=	tcf_generic_walker
  };
  
  MODULE_AUTHOR("Jamal Hadi Salim(2002)");
  MODULE_DESCRIPTION("Device Mirror/redirect actions");
  MODULE_LICENSE("GPL");

  static int __init mirred_init_module(void)

  {

  	int err = register_netdevice_notifier(&mirred_device_notifier);
  	if (err)
  		return err;

  	pr_info("Mirror/redirect action on
  ");

  	return tcf_register_action(&act_mirred_ops);
  }

  static void __exit mirred_cleanup_module(void)

  {

  	unregister_netdevice_notifier(&mirred_device_notifier);

  	tcf_unregister_action(&act_mirred_ops);
  }
  
  module_init(mirred_init_module);
  module_exit(mirred_cleanup_module);