On 2/2/24 1:21 AM, thinker.li@gmail.com wrote:

From: Kui-Feng Lee <redacted>

Pass the duration of a lifetime (in seconds) to the function
rt6_add_dflt_router() so that it can properly set the expiration time.

The function ndisc_router_discovery() is the only one that calls
rt6_add_dflt_router(), and it will later set the expiration time for the
route created by rt6_add_dflt_router(). However, there is a gap of time
between calling rt6_add_dflt_router() and setting the expiration time in
ndisc_router_discovery(). During this period, there is a possibility that a
new route may be removed from the routing table. By setting the correct
expiration time in rt6_add_dflt_router(), we can prevent this from
happening. The reason for setting RTF_EXPIRES in rt6_add_dflt_router() is
to start the Garbage Collection (GC) timer, as it only activates when a
route with RTF_EXPIRES is added to a table.

Signed-off-by: Kui-Feng Lee <redacted>
---
 include/net/ip6_route.h | 3 ++-
 net/ipv6/ndisc.c        | 3 ++-
 net/ipv6/route.c        | 4 +++-
 3 files changed, 7 insertions(+), 3 deletions(-)

Suggested-by: David Ahern <dsahern@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>