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3e9e84e92c
Without the prior commit, IPv6 GC cannot track exceptions tied
to permanent routes if they were originally added as temporary
routes.
Let's add a test case for the issue.
1. Add temporary routes
2. Create exceptions for the temporary routes
3. Promote the routes to permanent routes
4. Check if GC can find and purge the exceptions
A few notes:
+ At step 4, unlike other test cases, we cannot wait for
$GC_WAIT_TIME. While the exceptions are always iterable via
netlink (since it traverses the entire fib tree instead of
tb6_gc_hlist), rt6_nh_dump_exceptions() skips expired entries.
If we waited for the expiration time, we would be unable to
distinguish whether the exceptions were truly purged by GC or
just hidden due to being expired.
+ For the same reason, at step 2, we use ICMPv6 redirect message
instead of Packet Too Big message. This is because MTU exceptions
always have RTF_EXPIRES, and rt6_age_examine_exception() does not
respect the period specified by net.ipv6.route.flush=1.
+ We add a neighbour entry for the redirect target with NTF_ROUTER.
Without this, the exceptions would be removed at step 3 when the
fib6_may_remove_gc_list() is called.
Without the fix, the exceptions remain even after GC is triggered
by sysctl -wq net.ipv6.route.flush=1.
FAIL: Expected 0 routes, got 5
TEST: ipv6 route garbage collection (promote to permanent routes) [FAIL]
With the fix, GC purges the exceptions properly.
TEST: ipv6 route garbage collection (promote to permanent routes) [ OK ]
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260320072317.2561779-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>