[PATCH net-next 2/7] mptcp: reduce branching when writing MP_FAIL option
From: Mat Martineau <hidden>
Date: 2022-02-03 01:03:55
Also in:
mptcp
Subsystem:
networking [general], networking [mptcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthieu Baerts, Mat Martineau, Linus Torvalds
From: Matthieu Baerts <redacted> 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: Geliang Tang <redacted> Signed-off-by: Geliang Tang <redacted> Signed-off-by: Matthieu Baerts <redacted> Signed-off-by: Mat Martineau <redacted> --- net/mptcp/options.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 5d0b3c3e4655..ab054c389a5f 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c@@ -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;
--
2.35.1