linux/net/ipv6/fib6_rules.c
Ido Schimmel dcb18f762f ipv6: fib_rules: Dump rules during registration to FIB chain
Allow users of the FIB notification chain to receive a complete view of
the IPv6 FIB rules upon registration to the chain.

The integrity of the dump is ensured by a per-family sequence counter
that is incremented (under RTNL) whenever a rule is added or deleted.

All the sequence counters are read (under RTNL) and summed, prior and
after the dump. In case the counters differ, then the dump is either
restarted or the registration fails.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-03 15:36:00 -07:00

369 lines
8.4 KiB
C

/*
* 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/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);
}
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,
};
/* 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 (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;
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, 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;
}
err = rt->dst.error;
if (err != -EAGAIN)
goto out;
}
again:
ip6_rt_put(rt);
err = -EAGAIN;
rt = NULL;
goto out;
discard_pkt:
dst_hold(&rt->dst);
out:
arg->result = rt;
return err;
}
static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
{
struct rt6_info *rt = (struct rt6_info *) arg->result;
struct net_device *dev = NULL;
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;
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 && !rule->l3mdev) {
if (rule->table == RT6_TABLE_UNSPEC)
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;
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_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,
.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;
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);
}