Commit 902c8f86 authored by Matthieu Baerts's avatar Matthieu Baerts Committed by David S. Miller
Browse files

mptcp: reduce branching when writing MP_FAIL option 



MP_FAIL should be use in very rare cases, either when the TCP RST flag
is set -- with or without an MP_RST -- or with a DSS, see
mptcp_established_options().

Here, we do the same in mptcp_write_options().

Co-developed-by: default avatarGeliang Tang <geliang.tang@suse.com>
Signed-off-by: default avatarGeliang Tang <geliang.tang@suse.com>
Signed-off-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d7889cfa

net/mptcp/options.c

+19 −11
Original line number Diff line number Diff line
@@ -1267,17 +1267,6 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, 
	const struct sock *ssk = (const struct sock *)tp;

	struct mptcp_subflow_context *subflow;



	if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {

		subflow = mptcp_subflow_ctx(ssk);

		subflow->send_mp_fail = 0;



		*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,

				      TCPOLEN_MPTCP_FAIL,

				      0, 0);

		put_unaligned_be64(opts->fail_seq, ptr);

		ptr += 2;

	}



	/* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,

	 * see mptcp_established_options*()

	 */
@@ -1336,6 +1325,10 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, 
			}

			ptr += 1;

		}



		/* We might need to add MP_FAIL options in rare cases */

		if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions))

			goto mp_fail;

	} else if (OPTIONS_MPTCP_MPC & opts->suboptions) {

		u8 len, flag = MPTCP_CAP_HMAC_SHA256;
@@ -1476,6 +1469,21 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp, 
		put_unaligned_be64(opts->rcvr_key, ptr);

		ptr += 2;



		if (OPTION_MPTCP_RST & opts->suboptions)

			goto mp_rst;

		return;

	} else if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {

mp_fail:

		/* MP_FAIL is mutually exclusive with others except RST */

		subflow = mptcp_subflow_ctx(ssk);

		subflow->send_mp_fail = 0;



		*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,

				      TCPOLEN_MPTCP_FAIL,

				      0, 0);

		put_unaligned_be64(opts->fail_seq, ptr);

		ptr += 2;



		if (OPTION_MPTCP_RST & opts->suboptions)

			goto mp_rst;

		return;