From 0b834ba00ab5337e938c727e216e1f5249794717 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Sat, 26 Oct 2019 11:53:39 +0200 Subject: [PATCH] ipv4: fix route update on metric change. Since commit af4d768ad28c ("net/ipv4: Add support for specifying metric of connected routes"), when updating an IP address with a different metric, the associated connected route is updated, too. Still, the mentioned commit doesn't handle properly some corner cases: $ ip addr add dev eth0 192.168.1.0/24 $ ip addr add dev eth0 192.168.2.1/32 peer 192.168.2.2 $ ip addr add dev eth0 192.168.3.1/24 $ ip addr change dev eth0 192.168.1.0/24 metric 10 $ ip addr change dev eth0 192.168.2.1/32 peer 192.168.2.2 metric 10 $ ip addr change dev eth0 192.168.3.1/24 metric 10 $ ip -4 route 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.0 192.168.2.2 dev eth0 proto kernel scope link src 192.168.2.1 192.168.3.0/24 dev eth0 proto kernel scope link src 192.168.2.1 metric 10 Only the last route is correctly updated. The problem is the current test in fib_modify_prefix_metric(): if (!(dev->flags & IFF_UP) || ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) || ipv4_is_zeronet(prefix) || prefix == ifa->ifa_local || ifa->ifa_prefixlen == 32) Which should be the logical 'not' of the pre-existing test in fib_add_ifaddr(): if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) && (prefix != addr || ifa->ifa_prefixlen < 32)) To properly negate the original expression, we need to change the last logical 'or' to a logical 'and'. Fixes: af4d768ad28c ("net/ipv4: Add support for specifying metric of connected routes") Reported-and-suggested-by: Beniamino Galvani Signed-off-by: Paolo Abeni Reviewed-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/fib_frontend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index dde77f72e03e..71c78d223dfd 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -1148,7 +1148,7 @@ void fib_modify_prefix_metric(struct in_ifaddr *ifa, u32 new_metric) if (!(dev->flags & IFF_UP) || ifa->ifa_flags & (IFA_F_SECONDARY | IFA_F_NOPREFIXROUTE) || ipv4_is_zeronet(prefix) || - prefix == ifa->ifa_local || ifa->ifa_prefixlen == 32) + (prefix == ifa->ifa_local && ifa->ifa_prefixlen == 32)) return; /* add the new */