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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* IPv4 Forwarding Information Base: policy rules.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
* Thomas Graf <tgraf@suug.ch>
*
* Fixes:
* Rani Assaf : local_rule cannot be deleted
* Marc Boucher : routing by fwmark
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <linux/netlink.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/export.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/ip_fib.h>
#include <net/nexthop.h>
#include <net/fib_rules.h>
struct fib4_rule {
struct fib_rule common;
u8 dst_len;
u8 src_len;
u8 tos;
__be32 src;
__be32 srcmask;
__be32 dst;
__be32 dstmask;
#ifdef CONFIG_IP_ROUTE_CLASSID
u32 tclassid;
#endif
};
static bool fib4_rule_matchall(const struct fib_rule *rule)
{
struct fib4_rule *r = container_of(rule, struct fib4_rule, common);
if (r->dst_len || r->src_len || r->tos)
return false;
return fib_rule_matchall(rule);
}
bool fib4_rule_default(const struct fib_rule *rule)
{
if (!fib4_rule_matchall(rule) || rule->action != FR_ACT_TO_TBL ||
rule->l3mdev)
return false;
if (rule->table != RT_TABLE_LOCAL && rule->table != RT_TABLE_MAIN &&
rule->table != RT_TABLE_DEFAULT)
return false;
return true;
}
EXPORT_SYMBOL_GPL(fib4_rule_default);
int fib4_rules_dump(struct net *net, struct notifier_block *nb,
struct netlink_ext_ack *extack)
{
return fib_rules_dump(net, nb, AF_INET, extack);
}
unsigned int fib4_rules_seq_read(struct net *net)
{
return fib_rules_seq_read(net, AF_INET);
}
int __fib_lookup(struct net *net, struct flowi4 *flp,
struct fib_result *res, unsigned int flags)
{
struct fib_lookup_arg arg = {
.result = res,
.flags = flags,
};
int err;
/* update flow if oif or iif point to device enslaved to l3mdev */
l3mdev_update_flow(net, flowi4_to_flowi(flp));
err = fib_rules_lookup(net->ipv4.rules_ops, flowi4_to_flowi(flp), 0, &arg);
#ifdef CONFIG_IP_ROUTE_CLASSID
if (arg.rule)
res->tclassid = ((struct fib4_rule *)arg.rule)->tclassid;
else
res->tclassid = 0;
#endif
if (err == -ESRCH)
err = -ENETUNREACH;
return err;
}
EXPORT_SYMBOL_GPL(__fib_lookup);
static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
int flags, struct fib_lookup_arg *arg)
{
int err = -EAGAIN;
struct fib_table *tbl;
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;
}
rcu_read_lock();
tb_id = fib_rule_get_table(rule, arg);
tbl = fib_get_table(rule->fr_net, tb_id);
if (tbl)
err = fib_table_lookup(tbl, &flp->u.ip4,
(struct fib_result *)arg->result,
arg->flags);
rcu_read_unlock();
return err;
}
static bool fib4_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg)
{
struct fib_result *result = (struct fib_result *) arg->result;
struct net_device *dev = NULL;
if (result->fi) {
struct fib_nh_common *nhc = fib_info_nhc(result->fi, 0);
dev = nhc->nhc_dev;
}
/* do not accept result if the route does
* not meet the required prefix length
*/
if (result->prefixlen <= 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:
if (!(arg->flags & FIB_LOOKUP_NOREF))
fib_info_put(result->fi);
return true;
}
static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
{
struct fib4_rule *r = (struct fib4_rule *) rule;
struct flowi4 *fl4 = &fl->u.ip4;
__be32 daddr = fl4->daddr;
__be32 saddr = fl4->saddr;
if (((saddr ^ r->src) & r->srcmask) ||
((daddr ^ r->dst) & r->dstmask))
return 0;
if (r->tos && (r->tos != fl4->flowi4_tos))
return 0;
if (rule->ip_proto && (rule->ip_proto != fl4->flowi4_proto))
return 0;
if (fib_rule_port_range_set(&rule->sport_range) &&
!fib_rule_port_inrange(&rule->sport_range, fl4->fl4_sport))
return 0;
if (fib_rule_port_range_set(&rule->dport_range) &&
!fib_rule_port_inrange(&rule->dport_range, fl4->fl4_dport))
return 0;
return 1;
}
static struct fib_table *fib_empty_table(struct net *net)
{
u32 id = 1;
while (1) {
if (!fib_get_table(net, id))
return fib_new_table(net, id);
if (id++ == RT_TABLE_MAX)
break;
}
return NULL;
}
static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {
FRA_GENERIC_POLICY,
[FRA_FLOW] = { .type = NLA_U32 },
};
static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
struct fib_rule_hdr *frh,
struct nlattr **tb,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
int err = -EINVAL;
struct fib4_rule *rule4 = (struct fib4_rule *) rule;
if (frh->tos & ~IPTOS_TOS_MASK) {
NL_SET_ERR_MSG(extack, "Invalid tos");
goto errout;
}
/* split local/main if they are not already split */
err = fib_unmerge(net);
if (err)
goto errout;
if (rule->table == RT_TABLE_UNSPEC && !rule->l3mdev) {
if (rule->action == FR_ACT_TO_TBL) {
struct fib_table *table;
table = fib_empty_table(net);
if (!table) {
err = -ENOBUFS;
goto errout;
}
rule->table = table->tb_id;
}
}
if (frh->src_len)
rule4->src = nla_get_in_addr(tb[FRA_SRC]);
if (frh->dst_len)
rule4->dst = nla_get_in_addr(tb[FRA_DST]);
#ifdef CONFIG_IP_ROUTE_CLASSID
|