/*

   * net/sched/act_ipt.c		iptables target interface

   *
   *TODO: Add other tables. For now we only support the ipv4 table targets
   *
   *		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.
   *

   * Copyright:	Jamal Hadi Salim (2002-13)

   */

  #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/slab.h>

  #include <net/netlink.h>

  #include <net/pkt_sched.h>
  #include <linux/tc_act/tc_ipt.h>
  #include <net/tc_act/tc_ipt.h>
  
  #include <linux/netfilter_ipv4/ip_tables.h>

  static unsigned int ipt_net_id;

  static struct tc_action_ops act_ipt_ops;

  static unsigned int xt_net_id;

  static struct tc_action_ops act_xt_ops;

  static int ipt_init_target(struct net *net, struct xt_entry_target *t,
  			   char *table, unsigned int hook)

  {

  	struct xt_tgchk_param par;

  	struct xt_target *target;

  	struct ipt_entry e = {};

  	int ret = 0;

  	target = xt_request_find_target(AF_INET, t->u.user.name,
  					t->u.user.revision);

  	if (IS_ERR(target))
  		return PTR_ERR(target);

  	t->u.kernel.target = target;

  	memset(&par, 0, sizeof(par));

  	par.net       = net;

  	par.table     = table;

  	par.entryinfo = &e;

  	par.target    = target;
  	par.targinfo  = t->data;
  	par.hook_mask = hook;

  	par.family    = NFPROTO_IPV4;

  	ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);

  	if (ret < 0) {

  		module_put(t->u.kernel.target->me);

  		return ret;

  	}

  	return 0;

  }

  static void ipt_destroy_target(struct xt_entry_target *t)

  {

  	struct xt_tgdtor_param par = {
  		.target   = t->u.kernel.target,
  		.targinfo = t->data,

  		.family   = NFPROTO_IPV4,

  	};
  	if (par.target->destroy != NULL)
  		par.target->destroy(&par);
  	module_put(par.target->me);

  }

  static void tcf_ipt_release(struct tc_action *a, int bind)

  {

  	struct tcf_ipt *ipt = to_ipt(a);

  
  	if (ipt->tcfi_t) {
  		ipt_destroy_target(ipt->tcfi_t);
  		kfree(ipt->tcfi_t);
  	}

  	kfree(ipt->tcfi_tname);

  }

  static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  	[TCA_IPT_TABLE]	= { .type = NLA_STRING, .len = IFNAMSIZ },
  	[TCA_IPT_HOOK]	= { .type = NLA_U32 },
  	[TCA_IPT_INDEX]	= { .type = NLA_U32 },

  	[TCA_IPT_TARG]	= { .len = sizeof(struct xt_entry_target) },

  };

  static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,

  			  struct nlattr *est, struct tc_action **a,
  			  const struct tc_action_ops *ops, int ovr, int bind)

  {

  	struct tc_action_net *tn = net_generic(net, id);

  	struct nlattr *tb[TCA_IPT_MAX + 1];

  	struct tcf_ipt *ipt;

  	struct xt_entry_target *td, *t;

  	char *tname;

  	bool exists = false;
  	int ret = 0, err;

  	u32 hook = 0;
  	u32 index = 0;

  	if (nla == NULL)

  		return -EINVAL;

  	err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy, NULL);

  	if (err < 0)
  		return err;

  	if (tb[TCA_IPT_INDEX] != NULL)
  		index = nla_get_u32(tb[TCA_IPT_INDEX]);

  	exists = tcf_idr_check(tn, index, a, bind);

  	if (exists && bind)
  		return 0;
  
  	if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
  		if (exists)

  			tcf_idr_release(*a, bind);

  		return -EINVAL;

  	}

  	td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);

  	if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size) {
  		if (exists)

  			tcf_idr_release(*a, bind);

  		return -EINVAL;

  	}

  	if (!exists) {

  		ret = tcf_idr_create(tn, index, est, a, ops, bind,
  				     false);

  		if (ret)
  			return ret;

  		ret = ACT_P_CREATED;
  	} else {

  		if (bind)/* dont override defaults */
  			return 0;

  		tcf_idr_release(*a, bind);

  
  		if (!ovr)

  			return -EEXIST;

  	}

  	hook = nla_get_u32(tb[TCA_IPT_HOOK]);

  
  	err = -ENOMEM;
  	tname = kmalloc(IFNAMSIZ, GFP_KERNEL);

  	if (unlikely(!tname))

  		goto err1;

  	if (tb[TCA_IPT_TABLE] == NULL ||
  	    nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)

  		strcpy(tname, "mangle");

  	t = kmemdup(td, td->u.target_size, GFP_KERNEL);

  	if (unlikely(!t))

  		goto err2;

  	err = ipt_init_target(net, t, tname, hook);

  	if (err < 0)

  		goto err3;

  	ipt = to_ipt(*a);

  	spin_lock_bh(&ipt->tcf_lock);

  	if (ret != ACT_P_CREATED) {

  		ipt_destroy_target(ipt->tcfi_t);
  		kfree(ipt->tcfi_tname);
  		kfree(ipt->tcfi_t);

  	}

  	ipt->tcfi_tname = tname;
  	ipt->tcfi_t     = t;
  	ipt->tcfi_hook  = hook;
  	spin_unlock_bh(&ipt->tcf_lock);

  	if (ret == ACT_P_CREATED)

  		tcf_idr_insert(tn, *a);

  	return ret;
  
  err3:
  	kfree(t);
  err2:
  	kfree(tname);
  err1:

  	if (ret == ACT_P_CREATED)

  		tcf_idr_release(*a, bind);

  	return err;
  }

  static int tcf_ipt_init(struct net *net, struct nlattr *nla,

  			struct nlattr *est, struct tc_action **a, int ovr,

  			int bind)
  {

  	return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr,
  			      bind);

  }
  
  static int tcf_xt_init(struct net *net, struct nlattr *nla,

  		       struct nlattr *est, struct tc_action **a, int ovr,

  		       int bind)
  {

  	return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr,
  			      bind);

  }

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

  		   struct tcf_result *res)

  {
  	int ret = 0, result = 0;

  	struct tcf_ipt *ipt = to_ipt(a);

  	struct xt_action_param par;

  	struct nf_hook_state state = {
  		.net	= dev_net(skb->dev),
  		.in	= skb->dev,
  		.hook	= ipt->tcfi_hook,
  		.pf	= NFPROTO_IPV4,
  	};

  	if (skb_unclone(skb, GFP_ATOMIC))
  		return TC_ACT_UNSPEC;

  	spin_lock(&ipt->tcf_lock);

  	tcf_lastuse_update(&ipt->tcf_tm);

  	bstats_update(&ipt->tcf_bstats, skb);

  
  	/* yes, we have to worry about both in and out dev

  	 * worry later - danger - this API seems to have changed
  	 * from earlier kernels
  	 */

  	par.state    = &state;

  	par.target   = ipt->tcfi_t->u.kernel.target;
  	par.targinfo = ipt->tcfi_t->data;
  	ret = par.target->target(skb, &par);

  	switch (ret) {
  	case NF_ACCEPT:
  		result = TC_ACT_OK;
  		break;
  	case NF_DROP:
  		result = TC_ACT_SHOT;

  		ipt->tcf_qstats.drops++;

  		break;

  	case XT_CONTINUE:

  		result = TC_ACT_PIPE;
  		break;
  	default:

  		net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT
  ",
  				       ret);

  		result = TC_ACT_OK;

  		break;
  	}

  	spin_unlock(&ipt->tcf_lock);

  	return result;
  
  }

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

  {

  	unsigned char *b = skb_tail_pointer(skb);

  	struct tcf_ipt *ipt = to_ipt(a);

  	struct xt_entry_target *t;

  	struct tcf_t tm;
  	struct tc_cnt c;

  
  	/* for simple targets kernel size == user size

  	 * user name = target name
  	 * for foolproof you need to not assume this
  	 */

  	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);

  	if (unlikely(!t))

  		goto nla_put_failure;

  	c.bindcnt = ipt->tcf_bindcnt - bind;
  	c.refcnt = ipt->tcf_refcnt - ref;

  	strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);

  	if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
  	    nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
  	    nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
  	    nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
  	    nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
  		goto nla_put_failure;

  
  	tcf_tm_dump(&tm, &ipt->tcf_tm);

  	if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))

  		goto nla_put_failure;

  	kfree(t);
  	return skb->len;

  nla_put_failure:

  	nlmsg_trim(skb, b);

  	kfree(t);
  	return -1;
  }

  static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
  			  struct netlink_callback *cb, int type,

  			  const struct tc_action_ops *ops)

  {
  	struct tc_action_net *tn = net_generic(net, ipt_net_id);

  	return tcf_generic_walker(tn, skb, cb, type, ops);

  }

  static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index)

  {
  	struct tc_action_net *tn = net_generic(net, ipt_net_id);

  	return tcf_idr_search(tn, a, index);

  }

  static struct tc_action_ops act_ipt_ops = {
  	.kind		=	"ipt",
  	.type		=	TCA_ACT_IPT,

  	.owner		=	THIS_MODULE,
  	.act		=	tcf_ipt,
  	.dump		=	tcf_ipt_dump,

  	.cleanup	=	tcf_ipt_release,

  	.init		=	tcf_ipt_init,

  	.walk		=	tcf_ipt_walker,
  	.lookup		=	tcf_ipt_search,

  	.size		=	sizeof(struct tcf_ipt),

  };
  
  static __net_init int ipt_init_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, ipt_net_id);

  	return tc_action_net_init(tn, &act_ipt_ops);

  }
  
  static void __net_exit ipt_exit_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, ipt_net_id);
  
  	tc_action_net_exit(tn);
  }
  
  static struct pernet_operations ipt_net_ops = {
  	.init = ipt_init_net,
  	.exit = ipt_exit_net,
  	.id   = &ipt_net_id,
  	.size = sizeof(struct tc_action_net),

  };

  static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
  			 struct netlink_callback *cb, int type,

  			 const struct tc_action_ops *ops)

  {
  	struct tc_action_net *tn = net_generic(net, xt_net_id);

  	return tcf_generic_walker(tn, skb, cb, type, ops);

  }

  static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index)

  {
  	struct tc_action_net *tn = net_generic(net, xt_net_id);

  	return tcf_idr_search(tn, a, index);

  }

  static struct tc_action_ops act_xt_ops = {
  	.kind		=	"xt",

  	.type		=	TCA_ACT_XT,

  	.owner		=	THIS_MODULE,
  	.act		=	tcf_ipt,
  	.dump		=	tcf_ipt_dump,

  	.cleanup	=	tcf_ipt_release,

  	.init		=	tcf_xt_init,
  	.walk		=	tcf_xt_walker,
  	.lookup		=	tcf_xt_search,

  	.size		=	sizeof(struct tcf_ipt),

  };
  
  static __net_init int xt_init_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, xt_net_id);

  	return tc_action_net_init(tn, &act_xt_ops);

  }
  
  static void __net_exit xt_exit_net(struct net *net)
  {
  	struct tc_action_net *tn = net_generic(net, xt_net_id);
  
  	tc_action_net_exit(tn);
  }
  
  static struct pernet_operations xt_net_ops = {
  	.init = xt_init_net,
  	.exit = xt_exit_net,
  	.id   = &xt_net_id,
  	.size = sizeof(struct tc_action_net),

  };
  
  MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");

  MODULE_DESCRIPTION("Iptables target actions");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("act_xt");

  static int __init ipt_init_module(void)

  {

  	int ret1, ret2;

  	ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);

  	if (ret1 < 0)

  		pr_err("Failed to load xt action
  ");
  
  	ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);

  	if (ret2 < 0)

  		pr_err("Failed to load ipt action
  ");

  	if (ret1 < 0 && ret2 < 0) {

  		return ret1;

  	} else

  		return 0;

  }

  static void __exit ipt_cleanup_module(void)

  {

  	tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
  	tcf_unregister_action(&act_xt_ops, &xt_net_ops);

  }
  
  module_init(ipt_init_module);
  module_exit(ipt_cleanup_module);