mptcp: fix opt size when sending DSS + MP_FAIL

When these two options had to be sent -- which is not common -- the DSS
size was not being taken into account in the remaining size.

Additionally in this situation, the reported size was only the one of
the MP_FAIL which can cause issue if at the end, we need to write more
in the TCP options than previously said.

Here we use a dedicated variable for MP_FAIL size to keep the
WARN_ON_ONCE() just after.

Fixes: c25aeb4e09 ("mptcp: MP_FAIL suboption sending")
Acked-and-tested-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Matthieu Baerts 2022-01-06 14:06:36 -08:00 committed by David S. Miller
parent 14676c0478
commit 04fac2cae9

View file

@ -821,10 +821,13 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts))
ret = true;
else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) {
unsigned int mp_fail_size;
ret = true;
if (mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
*size += opt_size;
remaining -= opt_size;
if (mptcp_established_options_mp_fail(sk, &mp_fail_size,
remaining - opt_size, opts)) {
*size += opt_size + mp_fail_size;
remaining -= opt_size - mp_fail_size;
return true;
}
}