507 lines
12 KiB
C
507 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* net/ipv6/fib6_rules.c IPv6 Routing Policy Rules
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*
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* Copyright (C)2003-2006 Helsinki University of Technology
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* Copyright (C)2003-2006 USAGI/WIDE Project
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*
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* Authors
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* Thomas Graf <tgraf@suug.ch>
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* Ville Nuorvala <vnuorval@tcs.hut.fi>
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*/
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#include <linux/netdevice.h>
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#include <linux/notifier.h>
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#include <linux/export.h>
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#include <net/fib_rules.h>
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#include <net/ipv6.h>
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#include <net/addrconf.h>
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#include <net/ip6_route.h>
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#include <net/netlink.h>
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struct fib6_rule {
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struct fib_rule common;
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struct rt6key src;
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struct rt6key dst;
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u8 tclass;
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};
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static bool fib6_rule_matchall(const struct fib_rule *rule)
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{
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struct fib6_rule *r = container_of(rule, struct fib6_rule, common);
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if (r->dst.plen || r->src.plen || r->tclass)
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return false;
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return fib_rule_matchall(rule);
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}
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bool fib6_rule_default(const struct fib_rule *rule)
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{
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if (!fib6_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
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rule->l3mdev)
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return false;
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if (rule->table != RT6_TABLE_LOCAL && rule->table != RT6_TABLE_MAIN)
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return false;
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return true;
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}
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EXPORT_SYMBOL_GPL(fib6_rule_default);
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int fib6_rules_dump(struct net *net, struct notifier_block *nb)
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{
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return fib_rules_dump(net, nb, AF_INET6);
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}
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unsigned int fib6_rules_seq_read(struct net *net)
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{
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return fib_rules_seq_read(net, AF_INET6);
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}
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/* called with rcu lock held; no reference taken on fib6_info */
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int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
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struct fib6_result *res, int flags)
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{
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int err;
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if (net->ipv6.fib6_has_custom_rules) {
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struct fib_lookup_arg arg = {
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.lookup_ptr = fib6_table_lookup,
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.lookup_data = &oif,
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.result = res,
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.flags = FIB_LOOKUP_NOREF,
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};
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l3mdev_update_flow(net, flowi6_to_flowi(fl6));
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err = fib_rules_lookup(net->ipv6.fib6_rules_ops,
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flowi6_to_flowi(fl6), flags, &arg);
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} else {
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err = fib6_table_lookup(net, net->ipv6.fib6_local_tbl, oif,
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fl6, res, flags);
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if (err || res->f6i == net->ipv6.fib6_null_entry)
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err = fib6_table_lookup(net, net->ipv6.fib6_main_tbl,
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oif, fl6, res, flags);
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}
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return err;
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}
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struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
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const struct sk_buff *skb,
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int flags, pol_lookup_t lookup)
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{
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if (net->ipv6.fib6_has_custom_rules) {
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struct fib6_result res = {};
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struct fib_lookup_arg arg = {
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.lookup_ptr = lookup,
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.lookup_data = skb,
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.result = &res,
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.flags = FIB_LOOKUP_NOREF,
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};
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/* update flow if oif or iif point to device enslaved to l3mdev */
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l3mdev_update_flow(net, flowi6_to_flowi(fl6));
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fib_rules_lookup(net->ipv6.fib6_rules_ops,
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flowi6_to_flowi(fl6), flags, &arg);
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if (res.rt6)
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return &res.rt6->dst;
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} else {
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struct rt6_info *rt;
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rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
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if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
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return &rt->dst;
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ip6_rt_put_flags(rt, flags);
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rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
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if (rt->dst.error != -EAGAIN)
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return &rt->dst;
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ip6_rt_put_flags(rt, flags);
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}
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if (!(flags & RT6_LOOKUP_F_DST_NOREF))
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dst_hold(&net->ipv6.ip6_null_entry->dst);
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return &net->ipv6.ip6_null_entry->dst;
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}
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static int fib6_rule_saddr(struct net *net, struct fib_rule *rule, int flags,
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struct flowi6 *flp6, const struct net_device *dev)
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{
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struct fib6_rule *r = (struct fib6_rule *)rule;
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/* If we need to find a source address for this traffic,
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* we check the result if it meets requirement of the rule.
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*/
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if ((rule->flags & FIB_RULE_FIND_SADDR) &&
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r->src.plen && !(flags & RT6_LOOKUP_F_HAS_SADDR)) {
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struct in6_addr saddr;
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if (ipv6_dev_get_saddr(net, dev, &flp6->daddr,
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rt6_flags2srcprefs(flags), &saddr))
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return -EAGAIN;
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if (!ipv6_prefix_equal(&saddr, &r->src.addr, r->src.plen))
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return -EAGAIN;
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flp6->saddr = saddr;
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}
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return 0;
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}
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static int fib6_rule_action_alt(struct fib_rule *rule, struct flowi *flp,
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int flags, struct fib_lookup_arg *arg)
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{
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struct fib6_result *res = arg->result;
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struct flowi6 *flp6 = &flp->u.ip6;
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struct net *net = rule->fr_net;
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struct fib6_table *table;
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int err, *oif;
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u32 tb_id;
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switch (rule->action) {
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case FR_ACT_TO_TBL:
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break;
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case FR_ACT_UNREACHABLE:
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return -ENETUNREACH;
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case FR_ACT_PROHIBIT:
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return -EACCES;
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case FR_ACT_BLACKHOLE:
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default:
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return -EINVAL;
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}
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tb_id = fib_rule_get_table(rule, arg);
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table = fib6_get_table(net, tb_id);
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if (!table)
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return -EAGAIN;
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oif = (int *)arg->lookup_data;
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err = fib6_table_lookup(net, table, *oif, flp6, res, flags);
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if (!err && res->f6i != net->ipv6.fib6_null_entry)
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err = fib6_rule_saddr(net, rule, flags, flp6,
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res->nh->fib_nh_dev);
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else
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err = -EAGAIN;
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return err;
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}
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static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
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int flags, struct fib_lookup_arg *arg)
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{
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struct fib6_result *res = arg->result;
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struct flowi6 *flp6 = &flp->u.ip6;
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struct rt6_info *rt = NULL;
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struct fib6_table *table;
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struct net *net = rule->fr_net;
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pol_lookup_t lookup = arg->lookup_ptr;
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int err = 0;
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u32 tb_id;
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switch (rule->action) {
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case FR_ACT_TO_TBL:
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break;
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case FR_ACT_UNREACHABLE:
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err = -ENETUNREACH;
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rt = net->ipv6.ip6_null_entry;
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goto discard_pkt;
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default:
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case FR_ACT_BLACKHOLE:
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err = -EINVAL;
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rt = net->ipv6.ip6_blk_hole_entry;
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goto discard_pkt;
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case FR_ACT_PROHIBIT:
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err = -EACCES;
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rt = net->ipv6.ip6_prohibit_entry;
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goto discard_pkt;
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}
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tb_id = fib_rule_get_table(rule, arg);
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table = fib6_get_table(net, tb_id);
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if (!table) {
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err = -EAGAIN;
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goto out;
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}
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rt = lookup(net, table, flp6, arg->lookup_data, flags);
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if (rt != net->ipv6.ip6_null_entry) {
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err = fib6_rule_saddr(net, rule, flags, flp6,
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ip6_dst_idev(&rt->dst)->dev);
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if (err == -EAGAIN)
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goto again;
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err = rt->dst.error;
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if (err != -EAGAIN)
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goto out;
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}
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again:
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ip6_rt_put_flags(rt, flags);
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err = -EAGAIN;
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rt = NULL;
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goto out;
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discard_pkt:
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if (!(flags & RT6_LOOKUP_F_DST_NOREF))
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dst_hold(&rt->dst);
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out:
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res->rt6 = rt;
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return err;
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}
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static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
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int flags, struct fib_lookup_arg *arg)
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{
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if (arg->lookup_ptr == fib6_table_lookup)
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return fib6_rule_action_alt(rule, flp, flags, arg);
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return __fib6_rule_action(rule, flp, flags, arg);
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}
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static bool fib6_rule_suppress(struct fib_rule *rule, int flags, struct fib_lookup_arg *arg)
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{
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struct fib6_result *res = arg->result;
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struct rt6_info *rt = res->rt6;
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struct net_device *dev = NULL;
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if (!rt)
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return false;
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if (rt->rt6i_idev)
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dev = rt->rt6i_idev->dev;
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/* do not accept result if the route does
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* not meet the required prefix length
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*/
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if (rt->rt6i_dst.plen <= rule->suppress_prefixlen)
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goto suppress_route;
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/* do not accept result if the route uses a device
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* belonging to a forbidden interface group
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*/
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if (rule->suppress_ifgroup != -1 && dev && dev->group == rule->suppress_ifgroup)
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goto suppress_route;
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return false;
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suppress_route:
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ip6_rt_put_flags(rt, flags);
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return true;
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}
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static int fib6_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
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{
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struct fib6_rule *r = (struct fib6_rule *) rule;
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struct flowi6 *fl6 = &fl->u.ip6;
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if (r->dst.plen &&
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!ipv6_prefix_equal(&fl6->daddr, &r->dst.addr, r->dst.plen))
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return 0;
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/*
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* If FIB_RULE_FIND_SADDR is set and we do not have a
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* source address for the traffic, we defer check for
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* source address.
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*/
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if (r->src.plen) {
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if (flags & RT6_LOOKUP_F_HAS_SADDR) {
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if (!ipv6_prefix_equal(&fl6->saddr, &r->src.addr,
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r->src.plen))
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return 0;
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} else if (!(r->common.flags & FIB_RULE_FIND_SADDR))
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return 0;
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}
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if (r->tclass && r->tclass != ip6_tclass(fl6->flowlabel))
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return 0;
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if (rule->ip_proto && (rule->ip_proto != fl6->flowi6_proto))
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return 0;
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if (fib_rule_port_range_set(&rule->sport_range) &&
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!fib_rule_port_inrange(&rule->sport_range, fl6->fl6_sport))
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return 0;
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if (fib_rule_port_range_set(&rule->dport_range) &&
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!fib_rule_port_inrange(&rule->dport_range, fl6->fl6_dport))
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return 0;
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return 1;
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}
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static const struct nla_policy fib6_rule_policy[FRA_MAX+1] = {
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FRA_GENERIC_POLICY,
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};
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static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
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struct fib_rule_hdr *frh,
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struct nlattr **tb,
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struct netlink_ext_ack *extack)
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{
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int err = -EINVAL;
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struct net *net = sock_net(skb->sk);
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struct fib6_rule *rule6 = (struct fib6_rule *) rule;
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if (rule->action == FR_ACT_TO_TBL && !rule->l3mdev) {
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if (rule->table == RT6_TABLE_UNSPEC) {
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NL_SET_ERR_MSG(extack, "Invalid table");
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goto errout;
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}
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if (fib6_new_table(net, rule->table) == NULL) {
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err = -ENOBUFS;
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goto errout;
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}
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}
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if (frh->src_len)
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rule6->src.addr = nla_get_in6_addr(tb[FRA_SRC]);
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if (frh->dst_len)
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rule6->dst.addr = nla_get_in6_addr(tb[FRA_DST]);
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rule6->src.plen = frh->src_len;
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rule6->dst.plen = frh->dst_len;
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rule6->tclass = frh->tos;
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if (fib_rule_requires_fldissect(rule))
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net->ipv6.fib6_rules_require_fldissect++;
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net->ipv6.fib6_has_custom_rules = true;
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err = 0;
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errout:
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return err;
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}
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static int fib6_rule_delete(struct fib_rule *rule)
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{
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struct net *net = rule->fr_net;
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if (net->ipv6.fib6_rules_require_fldissect &&
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fib_rule_requires_fldissect(rule))
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net->ipv6.fib6_rules_require_fldissect--;
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return 0;
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}
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static int fib6_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
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struct nlattr **tb)
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{
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struct fib6_rule *rule6 = (struct fib6_rule *) rule;
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if (frh->src_len && (rule6->src.plen != frh->src_len))
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return 0;
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if (frh->dst_len && (rule6->dst.plen != frh->dst_len))
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return 0;
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if (frh->tos && (rule6->tclass != frh->tos))
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return 0;
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if (frh->src_len &&
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nla_memcmp(tb[FRA_SRC], &rule6->src.addr, sizeof(struct in6_addr)))
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return 0;
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if (frh->dst_len &&
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nla_memcmp(tb[FRA_DST], &rule6->dst.addr, sizeof(struct in6_addr)))
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return 0;
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return 1;
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}
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static int fib6_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
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struct fib_rule_hdr *frh)
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{
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struct fib6_rule *rule6 = (struct fib6_rule *) rule;
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frh->dst_len = rule6->dst.plen;
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frh->src_len = rule6->src.plen;
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frh->tos = rule6->tclass;
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if ((rule6->dst.plen &&
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nla_put_in6_addr(skb, FRA_DST, &rule6->dst.addr)) ||
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(rule6->src.plen &&
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nla_put_in6_addr(skb, FRA_SRC, &rule6->src.addr)))
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goto nla_put_failure;
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return 0;
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nla_put_failure:
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return -ENOBUFS;
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}
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static size_t fib6_rule_nlmsg_payload(struct fib_rule *rule)
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{
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return nla_total_size(16) /* dst */
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+ nla_total_size(16); /* src */
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}
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static const struct fib_rules_ops __net_initconst fib6_rules_ops_template = {
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.family = AF_INET6,
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.rule_size = sizeof(struct fib6_rule),
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.addr_size = sizeof(struct in6_addr),
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.action = fib6_rule_action,
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.match = fib6_rule_match,
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.suppress = fib6_rule_suppress,
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.configure = fib6_rule_configure,
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.delete = fib6_rule_delete,
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.compare = fib6_rule_compare,
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.fill = fib6_rule_fill,
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.nlmsg_payload = fib6_rule_nlmsg_payload,
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.nlgroup = RTNLGRP_IPV6_RULE,
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.policy = fib6_rule_policy,
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.owner = THIS_MODULE,
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.fro_net = &init_net,
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};
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static int __net_init fib6_rules_net_init(struct net *net)
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{
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struct fib_rules_ops *ops;
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int err = -ENOMEM;
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ops = fib_rules_register(&fib6_rules_ops_template, net);
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if (IS_ERR(ops))
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return PTR_ERR(ops);
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err = fib_default_rule_add(ops, 0, RT6_TABLE_LOCAL, 0);
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if (err)
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goto out_fib6_rules_ops;
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err = fib_default_rule_add(ops, 0x7FFE, RT6_TABLE_MAIN, 0);
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if (err)
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goto out_fib6_rules_ops;
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net->ipv6.fib6_rules_ops = ops;
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net->ipv6.fib6_rules_require_fldissect = 0;
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out:
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return err;
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out_fib6_rules_ops:
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fib_rules_unregister(ops);
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goto out;
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}
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static void __net_exit fib6_rules_net_exit(struct net *net)
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{
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rtnl_lock();
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fib_rules_unregister(net->ipv6.fib6_rules_ops);
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rtnl_unlock();
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}
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static struct pernet_operations fib6_rules_net_ops = {
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.init = fib6_rules_net_init,
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.exit = fib6_rules_net_exit,
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};
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int __init fib6_rules_init(void)
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{
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return register_pernet_subsys(&fib6_rules_net_ops);
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}
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void fib6_rules_cleanup(void)
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{
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unregister_pernet_subsys(&fib6_rules_net_ops);
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}
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