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Message-Id: <20190620190536.3157-1-dsahern@kernel.org>
Date: Thu, 20 Jun 2019 12:05:36 -0700
From: David Ahern <dsahern@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, kafai@...com, weiwan@...gle.com,
David Ahern <dsahern@...il.com>
Subject: [PATCH net-next] ipv6: Convert gateway validation to use fib6_info
From: David Ahern <dsahern@...il.com>
Gateway validation does not need a dst_entry, it only needs the fib
entry to validate the gateway resolution and egress device. So,
convert ip6_nh_lookup_table from ip6_pol_route to fib6_table_lookup
and ip6_route_check_nh to use fib6_lookup over rt6_lookup.
ip6_pol_route is a call to fib6_table_lookup and if successful a call
to fib6_select_path. From there the exception cache is searched for an
entry or a dst_entry is created to return to the caller. The exception
entry is not relevant for gateway validation, so what matters are the
calls to fib6_table_lookup and then fib6_select_path.
Similarly, rt6_lookup can be replaced with a call to fib6_lookup with
RT6_LOOKUP_F_IFACE set in flags (saddr is not set for gateway validation,
so RT6_LOOKUP_F_HAS_SADDR is not relevant). From there ip6_pol_route_lookup
lookup function is flipped to fib6_table_lookup for the per-table search.
Again, the exception cache search is not relevant, only the lookup with
path selection.
Adjust the users, ip6_route_check_nh_onlink and ip6_route_check_nh to
handle a fib6_info vs a rt6_info when performing validation checks.
Existing selftests fib-onlink-tests.sh and fib_tests.sh used to verify
the changes.
Signed-off-by: David Ahern <dsahern@...il.com>
---
net/ipv6/route.c | 119 ++++++++++++++++++++++++++-----------------------------
1 file changed, 57 insertions(+), 62 deletions(-)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c4d285fe0adc..4937084610b5 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3131,10 +3131,9 @@ static int ip6_dst_gc(struct dst_ops *ops)
return entries > rt_max_size;
}
-static struct rt6_info *ip6_nh_lookup_table(struct net *net,
- struct fib6_config *cfg,
- const struct in6_addr *gw_addr,
- u32 tbid, int flags)
+static int ip6_nh_lookup_table(struct net *net, struct fib6_config *cfg,
+ const struct in6_addr *gw_addr, u32 tbid,
+ int flags, struct fib6_result *res)
{
struct flowi6 fl6 = {
.flowi6_oif = cfg->fc_ifindex,
@@ -3142,25 +3141,23 @@ static struct rt6_info *ip6_nh_lookup_table(struct net *net,
.saddr = cfg->fc_prefsrc,
};
struct fib6_table *table;
- struct rt6_info *rt;
+ int err;
table = fib6_get_table(net, tbid);
if (!table)
- return NULL;
+ return -EINVAL;
if (!ipv6_addr_any(&cfg->fc_prefsrc))
flags |= RT6_LOOKUP_F_HAS_SADDR;
flags |= RT6_LOOKUP_F_IGNORE_LINKSTATE;
- rt = ip6_pol_route(net, table, cfg->fc_ifindex, &fl6, NULL, flags);
- /* if table lookup failed, fall back to full lookup */
- if (rt == net->ipv6.ip6_null_entry) {
- ip6_rt_put(rt);
- rt = NULL;
- }
+ err = fib6_table_lookup(net, table, cfg->fc_ifindex, &fl6, res, flags);
+ if (!err && res->f6i != net->ipv6.fib6_null_entry)
+ fib6_select_path(net, res, &fl6, cfg->fc_ifindex,
+ cfg->fc_ifindex != 0, NULL, flags);
- return rt;
+ return err;
}
static int ip6_route_check_nh_onlink(struct net *net,
@@ -3168,29 +3165,19 @@ static int ip6_route_check_nh_onlink(struct net *net,
const struct net_device *dev,
struct netlink_ext_ack *extack)
{
- u32 tbid = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
+ u32 tbid = l3mdev_fib_table_rcu(dev) ? : RT_TABLE_MAIN;
const struct in6_addr *gw_addr = &cfg->fc_gateway;
- u32 flags = RTF_LOCAL | RTF_ANYCAST | RTF_REJECT;
- struct fib6_info *from;
- struct rt6_info *grt;
+ struct fib6_result res = {};
int err;
- err = 0;
- grt = ip6_nh_lookup_table(net, cfg, gw_addr, tbid, 0);
- if (grt) {
- rcu_read_lock();
- from = rcu_dereference(grt->from);
- if (!grt->dst.error &&
- /* ignore match if it is the default route */
- from && !ipv6_addr_any(&from->fib6_dst.addr) &&
- (grt->rt6i_flags & flags || dev != grt->dst.dev)) {
- NL_SET_ERR_MSG(extack,
- "Nexthop has invalid gateway or device mismatch");
- err = -EINVAL;
- }
- rcu_read_unlock();
-
- ip6_rt_put(grt);
+ err = ip6_nh_lookup_table(net, cfg, gw_addr, tbid, 0, &res);
+ if (!err && !(res.fib6_flags & RTF_REJECT) &&
+ /* ignore match if it is the default route */
+ !ipv6_addr_any(&res.f6i->fib6_dst.addr) &&
+ (res.fib6_type != RTN_UNICAST || dev != res.nh->fib_nh_dev)) {
+ NL_SET_ERR_MSG(extack,
+ "Nexthop has invalid gateway or device mismatch");
+ err = -EINVAL;
}
return err;
@@ -3203,47 +3190,51 @@ static int ip6_route_check_nh(struct net *net,
{
const struct in6_addr *gw_addr = &cfg->fc_gateway;
struct net_device *dev = _dev ? *_dev : NULL;
- struct rt6_info *grt = NULL;
+ int flags = RT6_LOOKUP_F_IFACE;
+ struct fib6_result res = {};
int err = -EHOSTUNREACH;
if (cfg->fc_table) {
- int flags = RT6_LOOKUP_F_IFACE;
-
- grt = ip6_nh_lookup_table(net, cfg, gw_addr,
- cfg->fc_table, flags);
- if (grt) {
- if (grt->rt6i_flags & RTF_GATEWAY ||
- (dev && dev != grt->dst.dev)) {
- ip6_rt_put(grt);
- grt = NULL;
- }
- }
+ err = ip6_nh_lookup_table(net, cfg, gw_addr,
+ cfg->fc_table, flags, &res);
+ /* gw_addr can not require a gateway or resolve to a reject
+ * route. If a device is given, it must match the result.
+ */
+ if (err || res.fib6_flags & RTF_REJECT ||
+ res.nh->fib_nh_gw_family ||
+ (dev && dev != res.nh->fib_nh_dev))
+ err = -EHOSTUNREACH;
}
- if (!grt)
- grt = rt6_lookup(net, gw_addr, NULL, cfg->fc_ifindex, NULL, 1);
+ if (err < 0) {
+ struct flowi6 fl6 = {
+ .flowi6_oif = cfg->fc_ifindex,
+ .daddr = *gw_addr,
+ };
- if (!grt)
- goto out;
+ err = fib6_lookup(net, cfg->fc_ifindex, &fl6, &res, flags);
+ if (err || res.fib6_flags & RTF_REJECT ||
+ res.nh->fib_nh_gw_family)
+ err = -EHOSTUNREACH;
+
+ if (err)
+ return err;
+
+ fib6_select_path(net, &res, &fl6, cfg->fc_ifindex,
+ cfg->fc_ifindex != 0, NULL, flags);
+ }
+ err = 0;
if (dev) {
- if (dev != grt->dst.dev) {
- ip6_rt_put(grt);
- goto out;
- }
+ if (dev != res.nh->fib_nh_dev)
+ err = -EHOSTUNREACH;
} else {
- *_dev = dev = grt->dst.dev;
- *idev = grt->rt6i_idev;
+ *_dev = dev = res.nh->fib_nh_dev;
+ *idev = __in6_dev_get(dev);
dev_hold(dev);
- in6_dev_hold(grt->rt6i_idev);
+ in6_dev_hold(*idev);
}
- if (!(grt->rt6i_flags & RTF_GATEWAY))
- err = 0;
-
- ip6_rt_put(grt);
-
-out:
return err;
}
@@ -3284,11 +3275,15 @@ static int ip6_validate_gw(struct net *net, struct fib6_config *cfg,
goto out;
}
+ rcu_read_lock();
+
if (cfg->fc_flags & RTNH_F_ONLINK)
err = ip6_route_check_nh_onlink(net, cfg, dev, extack);
else
err = ip6_route_check_nh(net, cfg, _dev, idev);
+ rcu_read_unlock();
+
if (err)
goto out;
}
--
2.11.0
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