mptcp: fix a DSS option writing error

BugLink: https://bugs.launchpad.net/bugs/1959376
[ Upstream commit 110b6d1fe98fd7af9893992459b651594d789293 ]

'ptr += 1;' was omitted in the original code.

If the DSS is the last option -- which is what we have most of the
time -- that's not an issue. But it is if we need to send something else
after like a RM_ADDR or an MP_PRIO.

Fixes: 1bff1e43a30e ("mptcp: optimize out option generation")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index f69a1cadb13fc14b7ea27f6c662e7ecaa1125bd7..e515ba9ccb5d827726ef059a63b8b36023a8b7a9 100644 (file)
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1321,6 +1321,7 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
                                put_unaligned_be32(mpext->data_len << 16 |
                                                   TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
                        }
+                       ptr += 1;
                }
        } else if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK |
                    OPTION_MPTCP_MPC_ACK) & opts->suboptions) {