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![Ido Schimmel](/assets/img/avatar_default.png)
In commit c3852ef7f2
("ipv4: fib: Replay events when registering FIB
notifier") we dumped the FIB tables and replayed the events to the
passed notification block.
However, we merely sent a RULE_ADD notification in case custom rules
were in use. As explained in previous patches, this approach won't work
anymore. Instead, we should notify the caller about all the FIB rules
and let it act accordingly.
Upon registration to the FIB notification chain, replay a RULE_ADD
notification for each programmed FIB rule, custom or not. The integrity
of the dump is ensured by the mechanism introduced in the above
mentioned commit.
Prevent regressions by making sure current listeners correctly sanitize
the notified rules.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
427 lines
9.8 KiB
C
427 lines
9.8 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* IPv4 Forwarding Information Base: policy rules.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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* Thomas Graf <tgraf@suug.ch>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Fixes:
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* Rani Assaf : local_rule cannot be deleted
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* Marc Boucher : routing by fwmark
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/netlink.h>
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#include <linux/inetdevice.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <linux/export.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <net/tcp.h>
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#include <net/ip_fib.h>
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#include <net/fib_rules.h>
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struct fib4_rule {
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struct fib_rule common;
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u8 dst_len;
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u8 src_len;
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u8 tos;
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__be32 src;
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__be32 srcmask;
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__be32 dst;
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__be32 dstmask;
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#ifdef CONFIG_IP_ROUTE_CLASSID
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u32 tclassid;
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#endif
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};
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static bool fib4_rule_matchall(const struct fib_rule *rule)
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{
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struct fib4_rule *r = container_of(rule, struct fib4_rule, common);
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if (r->dst_len || r->src_len || r->tos)
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return false;
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return fib_rule_matchall(rule);
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}
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bool fib4_rule_default(const struct fib_rule *rule)
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{
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if (!fib4_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 != RT_TABLE_LOCAL && rule->table != RT_TABLE_MAIN &&
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rule->table != RT_TABLE_DEFAULT)
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return false;
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return true;
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}
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EXPORT_SYMBOL_GPL(fib4_rule_default);
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int __fib_lookup(struct net *net, struct flowi4 *flp,
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struct fib_result *res, unsigned int flags)
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{
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struct fib_lookup_arg arg = {
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.result = res,
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.flags = flags,
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};
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int err;
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/* update flow if oif or iif point to device enslaved to l3mdev */
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l3mdev_update_flow(net, flowi4_to_flowi(flp));
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err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg);
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#ifdef CONFIG_IP_ROUTE_CLASSID
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if (arg.rule)
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res->tclassid = ((struct fib4_rule *)arg.rule)->tclassid;
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else
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res->tclassid = 0;
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#endif
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if (err == -ESRCH)
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err = -ENETUNREACH;
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return err;
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}
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EXPORT_SYMBOL_GPL(__fib_lookup);
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static int fib4_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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int err = -EAGAIN;
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struct fib_table *tbl;
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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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rcu_read_lock();
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tb_id = fib_rule_get_table(rule, arg);
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tbl = fib_get_table(rule->fr_net, tb_id);
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if (tbl)
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err = fib_table_lookup(tbl, &flp->u.ip4,
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(struct fib_result *)arg->result,
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arg->flags);
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rcu_read_unlock();
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return err;
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}
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static bool fib4_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
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{
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struct fib_result *result = (struct fib_result *) arg->result;
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struct net_device *dev = NULL;
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if (result->fi)
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dev = result->fi->fib_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 (result->prefixlen <= 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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if (!(arg->flags & FIB_LOOKUP_NOREF))
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fib_info_put(result->fi);
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return true;
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}
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static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
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{
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struct fib4_rule *r = (struct fib4_rule *) rule;
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struct flowi4 *fl4 = &fl->u.ip4;
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__be32 daddr = fl4->daddr;
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__be32 saddr = fl4->saddr;
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if (((saddr ^ r->src) & r->srcmask) ||
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((daddr ^ r->dst) & r->dstmask))
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return 0;
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if (r->tos && (r->tos != fl4->flowi4_tos))
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return 0;
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return 1;
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}
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static struct fib_table *fib_empty_table(struct net *net)
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{
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u32 id;
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for (id = 1; id <= RT_TABLE_MAX; id++)
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if (!fib_get_table(net, id))
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return fib_new_table(net, id);
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return NULL;
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}
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static int call_fib_rule_notifier(struct notifier_block *nb, struct net *net,
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enum fib_event_type event_type,
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struct fib_rule *rule)
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{
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struct fib_rule_notifier_info info = {
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.rule = rule,
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};
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return call_fib_notifier(nb, net, event_type, &info.info);
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}
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static int call_fib_rule_notifiers(struct net *net,
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enum fib_event_type event_type,
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struct fib_rule *rule)
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{
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struct fib_rule_notifier_info info = {
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.rule = rule,
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};
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return call_fib_notifiers(net, event_type, &info.info);
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}
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/* Called with rcu_read_lock() */
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void fib_rules_notify(struct net *net, struct notifier_block *nb)
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{
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struct fib_rules_ops *ops = net->ipv4.rules_ops;
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struct fib_rule *rule;
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list_for_each_entry_rcu(rule, &ops->rules_list, list)
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call_fib_rule_notifier(nb, net, FIB_EVENT_RULE_ADD, rule);
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}
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static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
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FRA_GENERIC_POLICY,
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[FRA_FLOW] = { .type = NLA_U32 },
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};
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static int fib4_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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{
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struct net *net = sock_net(skb->sk);
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int err = -EINVAL;
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struct fib4_rule *rule4 = (struct fib4_rule *) rule;
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if (frh->tos & ~IPTOS_TOS_MASK)
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goto errout;
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/* split local/main if they are not already split */
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err = fib_unmerge(net);
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if (err)
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goto errout;
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if (rule->table == RT_TABLE_UNSPEC && !rule->l3mdev) {
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if (rule->action == FR_ACT_TO_TBL) {
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struct fib_table *table;
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table = fib_empty_table(net);
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if (!table) {
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err = -ENOBUFS;
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goto errout;
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}
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rule->table = table->tb_id;
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}
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}
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if (frh->src_len)
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rule4->src = nla_get_in_addr(tb[FRA_SRC]);
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if (frh->dst_len)
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rule4->dst = nla_get_in_addr(tb[FRA_DST]);
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#ifdef CONFIG_IP_ROUTE_CLASSID
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if (tb[FRA_FLOW]) {
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rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
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if (rule4->tclassid)
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net->ipv4.fib_num_tclassid_users++;
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}
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#endif
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rule4->src_len = frh->src_len;
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rule4->srcmask = inet_make_mask(rule4->src_len);
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rule4->dst_len = frh->dst_len;
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rule4->dstmask = inet_make_mask(rule4->dst_len);
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rule4->tos = frh->tos;
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net->ipv4.fib_has_custom_rules = true;
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call_fib_rule_notifiers(net, FIB_EVENT_RULE_ADD, rule);
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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 fib4_rule_delete(struct fib_rule *rule)
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{
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struct net *net = rule->fr_net;
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int err;
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/* split local/main if they are not already split */
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err = fib_unmerge(net);
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if (err)
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goto errout;
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#ifdef CONFIG_IP_ROUTE_CLASSID
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if (((struct fib4_rule *)rule)->tclassid)
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net->ipv4.fib_num_tclassid_users--;
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#endif
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net->ipv4.fib_has_custom_rules = true;
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call_fib_rule_notifiers(net, FIB_EVENT_RULE_DEL, rule);
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errout:
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return err;
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}
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static int fib4_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 fib4_rule *rule4 = (struct fib4_rule *) rule;
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if (frh->src_len && (rule4->src_len != frh->src_len))
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return 0;
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if (frh->dst_len && (rule4->dst_len != frh->dst_len))
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return 0;
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if (frh->tos && (rule4->tos != frh->tos))
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return 0;
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#ifdef CONFIG_IP_ROUTE_CLASSID
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if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))
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return 0;
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#endif
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if (frh->src_len && (rule4->src != nla_get_in_addr(tb[FRA_SRC])))
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return 0;
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if (frh->dst_len && (rule4->dst != nla_get_in_addr(tb[FRA_DST])))
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return 0;
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return 1;
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}
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static int fib4_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 fib4_rule *rule4 = (struct fib4_rule *) rule;
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frh->dst_len = rule4->dst_len;
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frh->src_len = rule4->src_len;
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frh->tos = rule4->tos;
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if ((rule4->dst_len &&
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nla_put_in_addr(skb, FRA_DST, rule4->dst)) ||
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(rule4->src_len &&
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nla_put_in_addr(skb, FRA_SRC, rule4->src)))
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goto nla_put_failure;
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#ifdef CONFIG_IP_ROUTE_CLASSID
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if (rule4->tclassid &&
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nla_put_u32(skb, FRA_FLOW, rule4->tclassid))
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goto nla_put_failure;
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#endif
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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 fib4_rule_nlmsg_payload(struct fib_rule *rule)
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{
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return nla_total_size(4) /* dst */
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+ nla_total_size(4) /* src */
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+ nla_total_size(4); /* flow */
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}
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static void fib4_rule_flush_cache(struct fib_rules_ops *ops)
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{
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rt_cache_flush(ops->fro_net);
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}
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static const struct fib_rules_ops __net_initconst fib4_rules_ops_template = {
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.family = AF_INET,
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.rule_size = sizeof(struct fib4_rule),
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.addr_size = sizeof(u32),
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.action = fib4_rule_action,
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.suppress = fib4_rule_suppress,
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.match = fib4_rule_match,
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.configure = fib4_rule_configure,
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.delete = fib4_rule_delete,
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.compare = fib4_rule_compare,
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.fill = fib4_rule_fill,
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.nlmsg_payload = fib4_rule_nlmsg_payload,
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.flush_cache = fib4_rule_flush_cache,
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.nlgroup = RTNLGRP_IPV4_RULE,
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.policy = fib4_rule_policy,
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.owner = THIS_MODULE,
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};
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static int fib_default_rules_init(struct fib_rules_ops *ops)
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{
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int err;
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err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, 0);
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if (err < 0)
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return err;
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err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
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if (err < 0)
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return err;
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err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
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if (err < 0)
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return err;
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return 0;
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}
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int __net_init fib4_rules_init(struct net *net)
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{
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int err;
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struct fib_rules_ops *ops;
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ops = fib_rules_register(&fib4_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_rules_init(ops);
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if (err < 0)
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goto fail;
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net->ipv4.rules_ops = ops;
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net->ipv4.fib_has_custom_rules = false;
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return 0;
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fail:
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/* also cleans all rules already added */
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fib_rules_unregister(ops);
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return err;
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}
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void __net_exit fib4_rules_exit(struct net *net)
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{
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fib_rules_unregister(net->ipv4.rules_ops);
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}
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