/* (C) 1999-2001 Paul `Rusty' Russell
   * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.

   */
  
  #include <linux/types.h>

  #include <linux/jiffies.h>

  #include <linux/timer.h>
  #include <linux/netfilter.h>

  #include <net/netfilter/nf_conntrack_l4proto.h>

  static unsigned int nf_ct_generic_timeout __read_mostly = 600*HZ;

  static bool nf_generic_should_process(u8 proto)
  {
  	switch (proto) {
  #ifdef CONFIG_NF_CT_PROTO_SCTP_MODULE
  	case IPPROTO_SCTP:
  		return false;
  #endif
  #ifdef CONFIG_NF_CT_PROTO_DCCP_MODULE
  	case IPPROTO_DCCP:
  		return false;
  #endif
  #ifdef CONFIG_NF_CT_PROTO_GRE_MODULE
  	case IPPROTO_GRE:
  		return false;
  #endif
  #ifdef CONFIG_NF_CT_PROTO_UDPLITE_MODULE
  	case IPPROTO_UDPLITE:
  		return false;
  #endif
  	default:
  		return true;
  	}
  }

  static inline struct nf_generic_net *generic_pernet(struct net *net)
  {
  	return &net->ct.nf_ct_proto.generic;
  }

  static bool generic_pkt_to_tuple(const struct sk_buff *skb,
  				 unsigned int dataoff,

  				 struct net *net, struct nf_conntrack_tuple *tuple)

  {
  	tuple->src.u.all = 0;
  	tuple->dst.u.all = 0;

  	return true;

  }

  static bool generic_invert_tuple(struct nf_conntrack_tuple *tuple,
  				 const struct nf_conntrack_tuple *orig)

  {
  	tuple->src.u.all = 0;
  	tuple->dst.u.all = 0;

  	return true;

  }
  
  /* Print out the per-protocol part of the tuple. */

  static void generic_print_tuple(struct seq_file *s,
  				const struct nf_conntrack_tuple *tuple)

  {

  }

  static unsigned int *generic_get_timeouts(struct net *net)
  {

  	return &(generic_pernet(net)->timeout);

  }

  /* Returns verdict for packet, or -1 for invalid. */

  static int generic_packet(struct nf_conn *ct,
  			  const struct sk_buff *skb,
  			  unsigned int dataoff,
  			  enum ip_conntrack_info ctinfo,
  			  u_int8_t pf,
  			  unsigned int hooknum,
  			  unsigned int *timeout)

  {

  	nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);

  	return NF_ACCEPT;
  }
  
  /* Called when a new connection for this protocol found. */

  static bool generic_new(struct nf_conn *ct, const struct sk_buff *skb,
  			unsigned int dataoff, unsigned int *timeouts)

  {

  	bool ret;
  
  	ret = nf_generic_should_process(nf_ct_protonum(ct));
  	if (!ret)
  		pr_warn_once("conntrack: generic helper won't handle protocol %d. Please consider loading the specific helper module.
  ",
  			     nf_ct_protonum(ct));
  	return ret;

  }

  #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
  
  #include <linux/netfilter/nfnetlink.h>
  #include <linux/netfilter/nfnetlink_cttimeout.h>

  static int generic_timeout_nlattr_to_obj(struct nlattr *tb[],
  					 struct net *net, void *data)

  {
  	unsigned int *timeout = data;

  	struct nf_generic_net *gn = generic_pernet(net);

  
  	if (tb[CTA_TIMEOUT_GENERIC_TIMEOUT])
  		*timeout =
  		    ntohl(nla_get_be32(tb[CTA_TIMEOUT_GENERIC_TIMEOUT])) * HZ;
  	else {
  		/* Set default generic timeout. */

  		*timeout = gn->timeout;

  	}
  
  	return 0;
  }
  
  static int
  generic_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
  {
  	const unsigned int *timeout = data;

  	if (nla_put_be32(skb, CTA_TIMEOUT_GENERIC_TIMEOUT, htonl(*timeout / HZ)))
  		goto nla_put_failure;

  
  	return 0;
  
  nla_put_failure:
          return -ENOSPC;
  }
  
  static const struct nla_policy
  generic_timeout_nla_policy[CTA_TIMEOUT_GENERIC_MAX+1] = {
  	[CTA_TIMEOUT_GENERIC_TIMEOUT]	= { .type = NLA_U32 },
  };
  #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */

  #ifdef CONFIG_SYSCTL

  static struct ctl_table generic_sysctl_table[] = {
  	{

  		.procname	= "nf_conntrack_generic_timeout",

  		.maxlen		= sizeof(unsigned int),
  		.mode		= 0644,

  		.proc_handler	= proc_dointvec_jiffies,

  	},

  	{ }

  };

  #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
  static struct ctl_table generic_compat_sysctl_table[] = {
  	{

  		.procname	= "ip_conntrack_generic_timeout",

  		.maxlen		= sizeof(unsigned int),
  		.mode		= 0644,

  		.proc_handler	= proc_dointvec_jiffies,

  	},

  	{ }

  };
  #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */

  #endif /* CONFIG_SYSCTL */

  static int generic_kmemdup_sysctl_table(struct nf_proto_net *pn,
  					struct nf_generic_net *gn)

  {

  #ifdef CONFIG_SYSCTL
  	pn->ctl_table = kmemdup(generic_sysctl_table,
  				sizeof(generic_sysctl_table),
  				GFP_KERNEL);
  	if (!pn->ctl_table)
  		return -ENOMEM;

  	pn->ctl_table[0].data = &gn->timeout;

  #endif
  	return 0;
  }

  static int generic_kmemdup_compat_sysctl_table(struct nf_proto_net *pn,
  					       struct nf_generic_net *gn)
  {
  #ifdef CONFIG_SYSCTL

  #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
  	pn->ctl_compat_table = kmemdup(generic_compat_sysctl_table,
  				       sizeof(generic_compat_sysctl_table),
  				       GFP_KERNEL);

  	if (!pn->ctl_compat_table)

  		return -ENOMEM;

  	pn->ctl_compat_table[0].data = &gn->timeout;
  #endif
  #endif
  	return 0;
  }

  static int generic_init_net(struct net *net, u_int16_t proto)
  {
  	int ret;
  	struct nf_generic_net *gn = generic_pernet(net);
  	struct nf_proto_net *pn = &gn->pn;
  
  	gn->timeout = nf_ct_generic_timeout;
  
  	ret = generic_kmemdup_compat_sysctl_table(pn, gn);
  	if (ret < 0)
  		return ret;
  
  	ret = generic_kmemdup_sysctl_table(pn, gn);
  	if (ret < 0)
  		nf_ct_kfree_compat_sysctl_table(pn);
  
  	return ret;
  }

  static struct nf_proto_net *generic_get_net_proto(struct net *net)
  {
  	return &net->ct.nf_ct_proto.generic.pn;
  }

  struct nf_conntrack_l4proto nf_conntrack_l4proto_generic __read_mostly =

  {
  	.l3proto		= PF_UNSPEC,

  	.l4proto		= 255,

  	.name			= "unknown",
  	.pkt_to_tuple		= generic_pkt_to_tuple,
  	.invert_tuple		= generic_invert_tuple,
  	.print_tuple		= generic_print_tuple,

  	.packet			= generic_packet,
  	.get_timeouts		= generic_get_timeouts,
  	.new			= generic_new,

  #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
  	.ctnl_timeout		= {
  		.nlattr_to_obj	= generic_timeout_nlattr_to_obj,
  		.obj_to_nlattr	= generic_timeout_obj_to_nlattr,
  		.nlattr_max	= CTA_TIMEOUT_GENERIC_MAX,
  		.obj_size	= sizeof(unsigned int),
  		.nla_policy	= generic_timeout_nla_policy,
  	},
  #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */

  	.init_net		= generic_init_net,

  	.get_net_proto		= generic_get_net_proto,

  };