net/ipv6/fib6_rules.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * net/ipv6/fib6_rules.c	IPv6 Routing Policy Rules
  *
  * Copyright (C)2003-2006 Helsinki University of Technology
  * Copyright (C)2003-2006 USAGI/WIDE Project
  *
  * Authors
  *	Thomas Graf		<tgraf@suug.ch>
  *	Ville Nuorvala		<vnuorval@tcs.hut.fi>
  */

 #include <linux/netdevice.h>
 #include <linux/notifier.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;
 };

 static bool fib6_rule_matchall(const struct fib_rule *rule)
 {
 	struct fib6_rule *r = container_of(rule, struct fib6_rule, common);

 	if (r->dst.plen || r->src.plen || r->tclass)
 		return false;
 	return fib_rule_matchall(rule);
 }

 bool fib6_rule_default(const struct fib_rule *rule)
 {
 	if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
 	    rule->l3mdev)
 		return false;
 	if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN)
 		return false;
 	return true;
 }
 EXPORT_SYMBOL_GPL(fib6_rule_default);

 int fib6_rules_dump(struct net *net, struct notifier_block *nb)
 {
 	return fib_rules_dump(net, nb, AF_INET6);
 }

 unsigned int fib6_rules_seq_read(struct net *net)
 {
 	return fib_rules_seq_read(net, AF_INET6);
 }

 /* called with rcu lock held; no reference taken on fib6_info */
 int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
 		struct fib6_result *res, int flags)
 {
 	int err;

 	if (net->ipv6.fib6_has_custom_rules) {
 		struct fib_lookup_arg arg = {
 			.lookup_ptr = fib6_table_lookup,
 			.lookup_data = &oif,
 			.result = res,
 			.flags = FIB_LOOKUP_NOREF,
 		};

 		l3mdev_update_flow(net, flowi6_to_flowi(fl6));

 		err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
 				       flowi6_to_flowi(fl6), flags, &arg);
 	} else {
 		err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
 					fl6, res, flags);
 		if (err || res->f6i == net->ipv6.fib6_null_entry)
 			err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
 						oif, fl6, res, flags);
 	}

 	return err;
 }

 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
 				   const struct sk_buff *skb,
 				   int flags, pol_lookup_t lookup)
 {
 	if (net->ipv6.fib6_has_custom_rules) {
 		struct fib6_result res = {};
 		struct fib_lookup_arg arg = {
 			.lookup_ptr = lookup,
 			.lookup_data = skb,
 			.result = &res,
 			.flags = FIB_LOOKUP_NOREF,
 		};

 		/* update flow if oif or iif point to device enslaved to l3mdev */
 		l3mdev_update_flow(net, flowi6_to_flowi(fl6));

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

 		if (res.rt6)
 			return &res.rt6->dst;
 	} else {
 		struct rt6_info *rt;

 		rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
 		if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
 			return &rt->dst;
 		ip6_rt_put_flags(rt, flags);
 		rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
 		if (rt->dst.error != -EAGAIN)
 			return &rt->dst;
 		ip6_rt_put_flags(rt, flags);
 	}

 	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
 		dst_hold(&net->ipv6.ip6_null_entry->dst);
 	return &net->ipv6.ip6_null_entry->dst;
 }

 static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags,
 			   struct flowi6 *flp6, const struct net_device *dev)
 {
 	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, dev, &flp6->daddr,
 				       rt6_flags2srcprefs(flags), &saddr))
 			return -EAGAIN;

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

 		flp6->saddr = saddr;
 	}

 	return 0;
 }

 static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
 				int flags, struct fib_lookup_arg *arg)
 {
 	struct fib6_result *res = arg->result;
 	struct flowi6 *flp6 = &flp->u.ip6;
 	struct net *net = rule->fr_net;
 	struct fib6_table *table;
 	int err, *oif;
 	u32 tb_id;

 	switch (rule->action) {
 	case FR_ACT_TO_TBL:
 		break;
 	case FR_ACT_UNREACHABLE:
 		return -ENETUNREACH;
 	case FR_ACT_PROHIBIT:
 		return -EACCES;
 	case FR_ACT_BLACKHOLE:
 	default:
 		return -EINVAL;
 	}

 	tb_id = fib_rule_get_table(rule, arg);
 	table = fib6_get_table(net, tb_id);
 	if (!table)
 		return -EAGAIN;

 	oif = (int *)arg->lookup_data;
 	err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
 	if (!err && res->f6i != net->ipv6.fib6_null_entry)
 		err = fib6_rule_saddr(net, rule, flags, flp6,
 				      res->nh->fib_nh_dev);
 	else
 		err = -EAGAIN;

 	return err;
 }

 static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
 			      int flags, struct fib_lookup_arg *arg)
 {
 	struct fib6_result *res = arg->result;
 	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;
 	int err = 0;
 	u32 tb_id;

 	switch (rule->action) {
 	case FR_ACT_TO_TBL:
 		break;
 	case FR_ACT_UNREACHABLE:
 		err = -ENETUNREACH;
 		rt = net->ipv6.ip6_null_entry;
 		goto discard_pkt;
 	default:
 	case FR_ACT_BLACKHOLE:
 		err = -EINVAL;
 		rt = net->ipv6.ip6_blk_hole_entry;
 		goto discard_pkt;
 	case FR_ACT_PROHIBIT:
 		err = -EACCES;
 		rt = net->ipv6.ip6_prohibit_entry;
 		goto discard_pkt;
 	}

 	tb_id = fib_rule_get_table(rule, arg);
 	table = fib6_get_table(net, tb_id);
 	if (!table) {
 		err = -EAGAIN;
 		goto out;
 	}

 	rt = lookup(net, table, flp6, arg->lookup_data, flags);
 	if (rt != net->ipv6.ip6_null_entry) {
 		err = fib6_rule_saddr(net, rule, flags, flp6,
 				      ip6_dst_idev(&rt->dst)->dev);

 		if (err == -EAGAIN)
 			goto again;

 		err = rt->dst.error;
 		if (err != -EAGAIN)
 			goto out;
 	}
 again:
 	ip6_rt_put_flags(rt, flags);
 	err = -EAGAIN;
 	rt = NULL;
 	goto out;

 discard_pkt:
 	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
 		dst_hold(&rt->dst);
 out:
 	res->rt6 = rt;
 	return err;
 }

 static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
 			    int flags, struct fib_lookup_arg *arg)
 {
 	if (arg->lookup_ptr == fib6_table_lookup)
 		return fib6_rule_action_alt(rule, flp, flags, arg);

 	return __fib6_rule_action(rule, flp, flags, arg);
 }

 static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
 {
 	struct fib6_result *res = arg->result;
 	struct rt6_info *rt = res->rt6;
 	struct net_device *dev = NULL;

 	if (!rt)
 		return false;

 	if (rt->rt6i_idev)
 		dev = rt->rt6i_idev->dev;

 	/* do not accept result if the route does
 	 * not meet the required prefix length
 	 */
 	if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
 		goto suppress_route;

 	/* do not accept result if the route uses a device
 	 * belonging to a forbidden interface group
 	 */
 	if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
 		goto suppress_route;

 	return false;

 suppress_route:
 	ip6_rt_put(rt);
 	return true;
 }

 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 != ip6_tclass(fl6->flowlabel))
 		return 0;

 	if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
 		return 0;

 	if (fib_rule_port_range_set(&rule->sport_range) &&
 	    !fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
 		return 0;

 	if (fib_rule_port_range_set(&rule->dport_range) &&
 	    !fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
 		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,
 			       struct netlink_ext_ack *extack)
 {
 	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 && !rule->l3mdev) {
 		if (rule->table == RT6_TABLE_UNSPEC) {
 			NL_SET_ERR_MSG(extack, "Invalid table");
 			goto errout;
 		}

 		if (fib6_new_table(net, rule->table) == NULL) {
 			err = -ENOBUFS;
 			goto errout;
 		}
 	}

 	if (frh->src_len)
 		rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);

 	if (frh->dst_len)
 		rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);

 	rule6->src.plen = frh->src_len;
 	rule6->dst.plen = frh->dst_len;
 	rule6->tclass = frh->tos;

 	if (fib_rule_requires_fldissect(rule))
 		net->ipv6.fib6_rules_require_fldissect++;

 	net->ipv6.fib6_has_custom_rules = true;
 	err = 0;
 errout:
 	return err;
 }

 static int fib6_rule_delete(struct fib_rule *rule)
 {
 	struct net *net = rule->fr_net;

 	if (net->ipv6.fib6_rules_require_fldissect &&
 	    fib_rule_requires_fldissect(rule))
 		net->ipv6.fib6_rules_require_fldissect--;

 	return 0;
 }

 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_in6_addr(skb, FRA_DST, &rule6->dst.addr)) ||
 	    (rule6->src.plen &&
 	     nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -ENOBUFS;
 }

 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_initconst 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,
 	.suppress		= fib6_rule_suppress,
 	.configure		= fib6_rule_configure,
 	.delete			= fib6_rule_delete,
 	.compare		= fib6_rule_compare,
 	.fill			= fib6_rule_fill,
 	.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);

 	err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0);
 	if (err)
 		goto out_fib6_rules_ops;

 	err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0);
 	if (err)
 		goto out_fib6_rules_ops;

 	net->ipv6.fib6_rules_ops = ops;
 	net->ipv6.fib6_rules_require_fldissect = 0;
 out:
 	return err;

 out_fib6_rules_ops:
 	fib_rules_unregister(ops);
 	goto out;
 }

 static void __net_exit fib6_rules_net_exit(struct net *net)
 {
 	rtnl_lock();
 	fib_rules_unregister(net->ipv6.fib6_rules_ops);
 	rtnl_unlock();
 }

 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);
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* net/ipv6/fib6_rules.c IPv6 Routing Policy Rules
	*
	* Copyright (C)2003-2006 Helsinki University of Technology
	* Copyright (C)2003-2006 USAGI/WIDE Project
	*
	* Authors
	* Thomas Graf <tgraf@suug.ch>
	* Ville Nuorvala <vnuorval@tcs.hut.fi>
	*/

	#include <linux/netdevice.h>
	#include <linux/notifier.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;
	};

	static bool fib6_rule_matchall(const struct fib_rule *rule)
	{
	struct fib6_rule *r = container_of(rule, struct fib6_rule, common);

	if (r->dst.plen \|\| r->src.plen \|\| r->tclass)
	return false;
	return fib_rule_matchall(rule);
	}

	bool fib6_rule_default(const struct fib_rule *rule)
	{
	if (!fib6_rule_matchall(rule) \|\| rule->action != FR_ACT_TO_TBL \|\|
	rule->l3mdev)
	return false;
	if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN)
	return false;
	return true;
	}
	EXPORT_SYMBOL_GPL(fib6_rule_default);

	int fib6_rules_dump(struct net net, struct notifier_block nb)
	{
	return fib_rules_dump(net, nb, AF_INET6);
	}

	unsigned int fib6_rules_seq_read(struct net *net)
	{
	return fib_rules_seq_read(net, AF_INET6);
	}

	/* called with rcu lock held; no reference taken on fib6_info */
	int fib6_lookup(struct net net, int oif, struct flowi6 fl6,
	struct fib6_result *res, int flags)
	{
	int err;

	if (net->ipv6.fib6_has_custom_rules) {
	struct fib_lookup_arg arg = {
	.lookup_ptr = fib6_table_lookup,
	.lookup_data = &oif,
	.result = res,
	.flags = FIB_LOOKUP_NOREF,
	};

	l3mdev_update_flow(net, flowi6_to_flowi(fl6));

	err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
	flowi6_to_flowi(fl6), flags, &arg);
	} else {
	err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
	fl6, res, flags);
	if (err \|\| res->f6i == net->ipv6.fib6_null_entry)
	err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
	oif, fl6, res, flags);
	}

	return err;
	}

	struct dst_entry fib6_rule_lookup(struct net net, struct flowi6 *fl6,
	const struct sk_buff *skb,
	int flags, pol_lookup_t lookup)
	{
	if (net->ipv6.fib6_has_custom_rules) {
	struct fib6_result res = {};
	struct fib_lookup_arg arg = {
	.lookup_ptr = lookup,
	.lookup_data = skb,
	.result = &res,
	.flags = FIB_LOOKUP_NOREF,
	};

	/* update flow if oif or iif point to device enslaved to l3mdev */
	l3mdev_update_flow(net, flowi6_to_flowi(fl6));

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

	if (res.rt6)
	return &res.rt6->dst;
	} else {
	struct rt6_info *rt;

	rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
	if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
	return &rt->dst;
	ip6_rt_put_flags(rt, flags);
	rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
	if (rt->dst.error != -EAGAIN)
	return &rt->dst;
	ip6_rt_put_flags(rt, flags);
	}

	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
	dst_hold(&net->ipv6.ip6_null_entry->dst);
	return &net->ipv6.ip6_null_entry->dst;
	}

	static int fib6_rule_saddr(struct net net, struct fib_rule rule, int flags,
	struct flowi6 flp6, const struct net_device dev)
	{
	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, dev, &flp6->daddr,
	rt6_flags2srcprefs(flags), &saddr))
	return -EAGAIN;

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

	flp6->saddr = saddr;
	}

	return 0;
	}

	static int fib6_rule_action_alt(struct fib_rule rule, struct flowi flp,
	int flags, struct fib_lookup_arg *arg)
	{
	struct fib6_result *res = arg->result;
	struct flowi6 *flp6 = &flp->u.ip6;
	struct net *net = rule->fr_net;
	struct fib6_table *table;
	int err, *oif;
	u32 tb_id;

	switch (rule->action) {
	case FR_ACT_TO_TBL:
	break;
	case FR_ACT_UNREACHABLE:
	return -ENETUNREACH;
	case FR_ACT_PROHIBIT:
	return -EACCES;
	case FR_ACT_BLACKHOLE:
	default:
	return -EINVAL;
	}

	tb_id = fib_rule_get_table(rule, arg);
	table = fib6_get_table(net, tb_id);
	if (!table)
	return -EAGAIN;

	oif = (int *)arg->lookup_data;
	err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
	if (!err && res->f6i != net->ipv6.fib6_null_entry)
	err = fib6_rule_saddr(net, rule, flags, flp6,
	res->nh->fib_nh_dev);
	else
	err = -EAGAIN;

	return err;
	}

	static int __fib6_rule_action(struct fib_rule rule, struct flowi flp,
	int flags, struct fib_lookup_arg *arg)
	{
	struct fib6_result *res = arg->result;
	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;
	int err = 0;
	u32 tb_id;

	switch (rule->action) {
	case FR_ACT_TO_TBL:
	break;
	case FR_ACT_UNREACHABLE:
	err = -ENETUNREACH;
	rt = net->ipv6.ip6_null_entry;
	goto discard_pkt;
	default:
	case FR_ACT_BLACKHOLE:
	err = -EINVAL;
	rt = net->ipv6.ip6_blk_hole_entry;
	goto discard_pkt;
	case FR_ACT_PROHIBIT:
	err = -EACCES;
	rt = net->ipv6.ip6_prohibit_entry;
	goto discard_pkt;
	}

	tb_id = fib_rule_get_table(rule, arg);
	table = fib6_get_table(net, tb_id);
	if (!table) {
	err = -EAGAIN;
	goto out;
	}

	rt = lookup(net, table, flp6, arg->lookup_data, flags);
	if (rt != net->ipv6.ip6_null_entry) {
	err = fib6_rule_saddr(net, rule, flags, flp6,
	ip6_dst_idev(&rt->dst)->dev);

	if (err == -EAGAIN)
	goto again;

	err = rt->dst.error;
	if (err != -EAGAIN)
	goto out;
	}
	again:
	ip6_rt_put_flags(rt, flags);
	err = -EAGAIN;
	rt = NULL;
	goto out;

	discard_pkt:
	if (!(flags & RT6_LOOKUP_F_DST_NOREF))
	dst_hold(&rt->dst);
	out:
	res->rt6 = rt;
	return err;
	}

	static int fib6_rule_action(struct fib_rule rule, struct flowi flp,
	int flags, struct fib_lookup_arg *arg)
	{
	if (arg->lookup_ptr == fib6_table_lookup)
	return fib6_rule_action_alt(rule, flp, flags, arg);

	return __fib6_rule_action(rule, flp, flags, arg);
	}

	static bool fib6_rule_suppress(struct fib_rule rule, struct fib_lookup_arg arg)
	{
	struct fib6_result *res = arg->result;
	struct rt6_info *rt = res->rt6;
	struct net_device *dev = NULL;

	if (!rt)
	return false;

	if (rt->rt6i_idev)
	dev = rt->rt6i_idev->dev;

	/* do not accept result if the route does
	* not meet the required prefix length
	*/
	if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
	goto suppress_route;

	/* do not accept result if the route uses a device
	* belonging to a forbidden interface group
	*/
	if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
	goto suppress_route;

	return false;

	suppress_route:
	ip6_rt_put(rt);
	return true;
	}

	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 != ip6_tclass(fl6->flowlabel))
	return 0;

	if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
	return 0;

	if (fib_rule_port_range_set(&rule->sport_range) &&
	!fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
	return 0;

	if (fib_rule_port_range_set(&rule->dport_range) &&
	!fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
	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,
	struct netlink_ext_ack *extack)
	{
	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 && !rule->l3mdev) {
	if (rule->table == RT6_TABLE_UNSPEC) {
	NL_SET_ERR_MSG(extack, "Invalid table");
	goto errout;
	}

	if (fib6_new_table(net, rule->table) == NULL) {
	err = -ENOBUFS;
	goto errout;
	}
	}

	if (frh->src_len)
	rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);

	if (frh->dst_len)
	rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);

	rule6->src.plen = frh->src_len;
	rule6->dst.plen = frh->dst_len;
	rule6->tclass = frh->tos;

	if (fib_rule_requires_fldissect(rule))
	net->ipv6.fib6_rules_require_fldissect++;

	net->ipv6.fib6_has_custom_rules = true;
	err = 0;
	errout:
	return err;
	}

	static int fib6_rule_delete(struct fib_rule *rule)
	{
	struct net *net = rule->fr_net;

	if (net->ipv6.fib6_rules_require_fldissect &&
	fib_rule_requires_fldissect(rule))
	net->ipv6.fib6_rules_require_fldissect--;

	return 0;
	}

	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_in6_addr(skb, FRA_DST, &rule6->dst.addr)) \|\|
	(rule6->src.plen &&
	nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -ENOBUFS;
	}

	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_initconst 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,
	.suppress = fib6_rule_suppress,
	.configure = fib6_rule_configure,
	.delete = fib6_rule_delete,
	.compare = fib6_rule_compare,
	.fill = fib6_rule_fill,
	.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);

	err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0);
	if (err)
	goto out_fib6_rules_ops;

	err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0);
	if (err)
	goto out_fib6_rules_ops;

	net->ipv6.fib6_rules_ops = ops;
	net->ipv6.fib6_rules_require_fldissect = 0;
	out:
	return err;

	out_fib6_rules_ops:
	fib_rules_unregister(ops);
	goto out;
	}

	static void __net_exit fib6_rules_net_exit(struct net *net)
	{
	rtnl_lock();
	fib_rules_unregister(net->ipv6.fib6_rules_ops);
	rtnl_unlock();
	}

	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);
	}