ipv6: fib6_rules: flush route cache when rule is changed

stable inclusion
from stable-v4.19.311
commit 95db6e62a2d920abf43c169e51046adb9f394ef0
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IA7YCW
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=95db6e62a2d920abf43c169e51046adb9f394ef0



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[ Upstream commit c4386ab4f6c600f75fdfd21143f89bac3e625d0d ]

When rule policy is changed, ipv6 socket cache is not refreshed.
The sock's skb still uses a outdated route cache and was sent to
a wrong interface.

To avoid this error we should update fib node's version when
rule is changed. Then skb's route will be reroute checked as
route cache version is already different with fib node version.
The route cache is refreshed to match the latest rule.

Fixes: 101367c2 ("[IPV6]: Policy Routing Rules")
Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com>
Signed-off-by: Lena Wang <lena.wang@mediatek.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com>