/*
   * net/ipv6/fib6_rules.c	IPv6 Routing Policy Rules
   *
   * Copyright (C)2003-2006 Helsinki University of Technology
   * Copyright (C)2003-2006 USAGI/WIDE Project
   *
   *	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, version 2.
   *
   * Authors
   *	Thomas Graf		<tgraf@suug.ch>
   *	Ville Nuorvala		<vnuorval@tcs.hut.fi>
   */

  #include <linux/netdevice.h>

  #include <linux/export.h>

  
  #include <net/fib_rules.h>
  #include <net/ipv6.h>

  #include <net/addrconf.h>

  #include <net/ip6_route.h>
  #include <net/netlink.h>
  
  struct fib6_rule
  {
  	struct fib_rule		common;
  	struct rt6key		src;
  	struct rt6key		dst;
  	u8			tclass;
  };

  struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,

  				   int flags, pol_lookup_t lookup)

  {
  	struct fib_lookup_arg arg = {
  		.lookup_ptr = lookup,

  		.flags = FIB_LOOKUP_NOREF,

  	};

  	fib_rules_lookup(net->ipv6.fib6_rules_ops,
  			 flowi6_to_flowi(fl6), flags, &arg);

  	if (arg.result)

  		return arg.result;

  	dst_hold(&net->ipv6.ip6_null_entry->dst);
  	return &net->ipv6.ip6_null_entry->dst;

  }

  static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
  			    int flags, struct fib_lookup_arg *arg)

  {

  	struct flowi6 *flp6 = &flp->u.ip6;

  	struct rt6_info *rt = NULL;
  	struct fib6_table *table;

  	struct net *net = rule->fr_net;

  	pol_lookup_t lookup = arg->lookup_ptr;
  
  	switch (rule->action) {
  	case FR_ACT_TO_TBL:
  		break;
  	case FR_ACT_UNREACHABLE:

  		rt = net->ipv6.ip6_null_entry;

  		goto discard_pkt;
  	default:
  	case FR_ACT_BLACKHOLE:

  		rt = net->ipv6.ip6_blk_hole_entry;

  		goto discard_pkt;
  	case FR_ACT_PROHIBIT:

  		rt = net->ipv6.ip6_prohibit_entry;

  		goto discard_pkt;
  	}

  	table = fib6_get_table(net, rule->table);

  	if (table)

  		rt = lookup(net, table, flp6, flags);

  	if (rt != net->ipv6.ip6_null_entry) {

  		struct fib6_rule *r = (struct fib6_rule *)rule;
  
  		/*
  		 * If we need to find a source address for this traffic,
  		 * we check the result if it meets requirement of the rule.
  		 */
  		if ((rule->flags & FIB_RULE_FIND_SADDR) &&
  		    r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
  			struct in6_addr saddr;

  			if (ipv6_dev_get_saddr(net,

  					       ip6_dst_idev(&rt->dst)->dev,

  					       &flp6->daddr,

  					       rt6_flags2srcprefs(flags),

  					       &saddr))

  				goto again;
  			if (!ipv6_prefix_equal(&saddr, &r->src.addr,
  					       r->src.plen))
  				goto again;

  			flp6->saddr = saddr;

  		}

  		goto out;

  	}
  again:

  	dst_release(&rt->dst);

  	rt = NULL;
  	goto out;

  discard_pkt:

  	dst_hold(&rt->dst);

  out:
  	arg->result = rt;
  	return rt == NULL ? -EAGAIN : 0;
  }
  
  
  static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
  {
  	struct fib6_rule *r = (struct fib6_rule *) rule;

  	struct flowi6 *fl6 = &fl->u.ip6;

  	if (r->dst.plen &&

  	    !ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))

  		return 0;

  	/*
  	 * If FIB_RULE_FIND_SADDR is set and we do not have a
  	 * source address for the traffic, we defer check for
  	 * source address.
  	 */

  	if (r->src.plen) {

  		if (flags & RT6_LOOKUP_F_HAS_SADDR) {

  			if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,

  					       r->src.plen))
  				return 0;
  		} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))

  			return 0;
  	}

  	if (r->tclass && r->tclass != ((ntohl(fl6->flowlabel) >> 20) & 0xff))

  		return 0;

  	return 1;
  }

  static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {

  	FRA_GENERIC_POLICY,

  };
  
  static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,

  			       struct fib_rule_hdr *frh,

  			       struct nlattr **tb)
  {
  	int err = -EINVAL;

  	struct net *net = sock_net(skb->sk);

  	struct fib6_rule *rule6 = (struct fib6_rule *) rule;

  	if (rule->action == FR_ACT_TO_TBL) {
  		if (rule->table == RT6_TABLE_UNSPEC)
  			goto errout;

  		if (fib6_new_table(net, rule->table) == NULL) {

  			err = -ENOBUFS;
  			goto errout;
  		}
  	}

  	if (frh->src_len)

  		nla_memcpy(&rule6->src.addr, tb[FRA_SRC],
  			   sizeof(struct in6_addr));

  	if (frh->dst_len)

  		nla_memcpy(&rule6->dst.addr, tb[FRA_DST],
  			   sizeof(struct in6_addr));
  
  	rule6->src.plen = frh->src_len;
  	rule6->dst.plen = frh->dst_len;
  	rule6->tclass = frh->tos;
  
  	err = 0;
  errout:
  	return err;
  }
  
  static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
  			     struct nlattr **tb)
  {
  	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
  
  	if (frh->src_len && (rule6->src.plen != frh->src_len))
  		return 0;
  
  	if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
  		return 0;
  
  	if (frh->tos && (rule6->tclass != frh->tos))
  		return 0;

  	if (frh->src_len &&

  	    nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
  		return 0;

  	if (frh->dst_len &&

  	    nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
  		return 0;
  
  	return 1;
  }
  
  static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,

  			  struct fib_rule_hdr *frh)

  {
  	struct fib6_rule *rule6 = (struct fib6_rule *) rule;

  	frh->dst_len = rule6->dst.plen;
  	frh->src_len = rule6->src.plen;
  	frh->tos = rule6->tclass;
  
  	if (rule6->dst.plen)
  		NLA_PUT(skb, FRA_DST, sizeof(struct in6_addr),
  			&rule6->dst.addr);
  
  	if (rule6->src.plen)
  		NLA_PUT(skb, FRA_SRC, sizeof(struct in6_addr),
  			&rule6->src.addr);
  
  	return 0;
  
  nla_put_failure:
  	return -ENOBUFS;
  }

  static u32 fib6_rule_default_pref(struct fib_rules_ops *ops)

  {
  	return 0x3FFF;
  }

  static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
  {
  	return nla_total_size(16) /* dst */
  	       + nla_total_size(16); /* src */
  }

  static const struct fib_rules_ops __net_initdata fib6_rules_ops_template = {

  	.family			= AF_INET6,

  	.rule_size		= sizeof(struct fib6_rule),

  	.addr_size		= sizeof(struct in6_addr),

  	.action			= fib6_rule_action,
  	.match			= fib6_rule_match,
  	.configure		= fib6_rule_configure,
  	.compare		= fib6_rule_compare,
  	.fill			= fib6_rule_fill,
  	.default_pref		= fib6_rule_default_pref,

  	.nlmsg_payload		= fib6_rule_nlmsg_payload,

  	.nlgroup		= RTNLGRP_IPV6_RULE,
  	.policy			= fib6_rule_policy,

  	.owner			= THIS_MODULE,

  	.fro_net		= &init_net,

  };

  static int __net_init fib6_rules_net_init(struct net *net)

  {

  	struct fib_rules_ops *ops;

  	int err = -ENOMEM;

  	ops = fib_rules_register(&fib6_rules_ops_template, net);
  	if (IS_ERR(ops))
  		return PTR_ERR(ops);
  	net->ipv6.fib6_rules_ops = ops;

  	err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,

  				   RT6_TABLE_LOCAL, 0);

  	if (err)
  		goto out_fib6_rules_ops;

  	err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
  				   0x7FFE, RT6_TABLE_MAIN, 0);
  	if (err)

  		goto out_fib6_rules_ops;

  out:

  	return err;

  out_fib6_rules_ops:

  	fib_rules_unregister(ops);

  	goto out;

  }

  static void __net_exit fib6_rules_net_exit(struct net *net)

  {
  	fib_rules_unregister(net->ipv6.fib6_rules_ops);

  }
  
  static struct pernet_operations fib6_rules_net_ops = {
  	.init = fib6_rules_net_init,
  	.exit = fib6_rules_net_exit,
  };
  
  int __init fib6_rules_init(void)
  {
  	return register_pernet_subsys(&fib6_rules_net_ops);
  }

  void fib6_rules_cleanup(void)
  {

  	unregister_pernet_subsys(&fib6_rules_net_ops);

  }