[PATCH] net: ipv6: fix __rt6_purge_dflt_routers when forwarding is not set on all ifaces

From: Brian Vazquez
Date: Tue Sep 01 2020 - 02:58:08 EST


The problem is exposed when the system has multiple ifaces and
forwarding is enabled on a subset of them, __rt6_purge_dflt_routers will
clean the default route on all the ifaces which is not desired.

This patches fixes that by cleaning only the routes where the iface has
forwarding enabled.

Fixes: 830218c1add1 ("net: ipv6: Fix processing of RAs in presence of VRF")
Cc: David Ahern <dsa@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Brian Vazquez <brianvv@xxxxxxxxxx>
---
net/ipv6/route.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 5e7e25e2523a..41181cd489ea 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4283,6 +4283,7 @@ static void __rt6_purge_dflt_routers(struct net *net,
struct fib6_table *table)
{
struct fib6_info *rt;
+ bool deleted = false;

restart:
rcu_read_lock();
@@ -4291,16 +4292,19 @@ static void __rt6_purge_dflt_routers(struct net *net,
struct inet6_dev *idev = dev ? __in6_dev_get(dev) : NULL;

if (rt->fib6_flags & (RTF_DEFAULT | RTF_ADDRCONF) &&
- (!idev || idev->cnf.accept_ra != 2) &&
+ (!idev || (idev->cnf.forwarding == 1 &&
+ idev->cnf.accept_ra != 2)) &&
fib6_info_hold_safe(rt)) {
rcu_read_unlock();
ip6_del_rt(net, rt, false);
+ deleted = true;
goto restart;
}
}
rcu_read_unlock();

- table->flags &= ~RT6_TABLE_HAS_DFLT_ROUTER;
+ if (deleted)
+ table->flags &= ~RT6_TABLE_HAS_DFLT_ROUTER;
}

void rt6_purge_dflt_routers(struct net *net)
--
2.28.0.402.g5ffc5be6b7-goog