[PATCH net] ipv6: fix prefix route expiry in modify_prefix_route()

[Qishuai Liu <lqs@lqs.me>]

modify_prefix_route() is given the lifetime in clock_t relative to now,
but fib6_set_expires() wants an absolute jiffies value. So when a
permanent address is changed to a finite valid_lft, the prefix route
ends up already expired and GC removes it.

Steps to reproduce:

  ip link add dummy9 type dummy
  ip link set dummy9 up
  ip -6 addr add 2001:db8:9::1/64 dev dummy9
  ip -6 addr change 2001:db8:9::1/64 dev dummy9 valid_lft 3600 preferred_lft 3600
  ip -6 route show dev dummy9    # expires is negative

Fixes: 8308f3ff1753 ("net/ipv6: Add support for specifying metric of connected routes")
Signed-off-by: Qishuai Liu <lqs@lqs.me>
---
 net/ipv6/addrconf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9d89be7e0544..c90ee6dd7446 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4874,7 +4874,7 @@ static int modify_prefix_route(struct net *net, struct inet6_ifaddr *ifp,
 			fib6_clean_expires(f6i);
 			fib6_may_remove_gc_list(net, f6i);
 		} else {
-			fib6_set_expires(f6i, expires);
+			fib6_set_expires(f6i, jiffies + clock_t_to_jiffies(expires));
 			fib6_add_gc_list(f6i);
 		}
 
-- 
2.43.0