netfilter: conntrack: unify established states for SCTP paths

stable inclusion
from stable-v5.10.166
commit 743435cd1705b4a3a4b8e73a538c4c1a1efc7edb
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I87FRA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=743435cd1705b4a3a4b8e73a538c4c1a1efc7edb



--------------------------------

commit a44b7651 upstream.

An SCTP endpoint can start an association through a path and tear it
down over another one. That means the initial path will not see the
shutdown sequence, and the conntrack entry will remain in ESTABLISHED
state for 5 days.

By merging the HEARTBEAT_ACKED and ESTABLISHED states into one
ESTABLISHED state, there remains no difference between a primary or
secondary path. The timeout for the merged ESTABLISHED state is set to
210 seconds (hb_interval * max_path_retrans + rto_max). So, even if a
path doesn't see the shutdown sequence, it will expire in a reasonable
amount of time.

With this change in place, there is now more than one state from which
we can transition to ESTABLISHED, COOKIE_ECHOED and HEARTBEAT_SENT, so
handle the setting of ASSURED bit whenever a state change has happened
and the new state is ESTABLISHED. Removed the check for dir==REPLY since
the transition to ESTABLISHED can happen only in the reply direction.

Fixes: 9fb9cbb1 ("[NETFILTER]: Add nf_conntrack subsystem.")
Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>