diff mbox series

[net-next,2/7] mptcp: reduce branching when writing MP_FAIL option

Message ID 20220203010343.113421-3-mathew.j.martineau@linux.intel.com (mailing list archive)
State Accepted
Commit 902c8f8648828c9293533cc54393f163fb594d06
Delegated to: Netdev Maintainers
Headers show
Series mptcp: Miscellaneous changes for 5.18 | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2 this patch: 2
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 20 this patch: 20
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 7 this patch: 7
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 48 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mat Martineau Feb. 3, 2022, 1:03 a.m. UTC 
From: Matthieu Baerts <matthieu.baerts@tessares.net>

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 <geliang.tang@suse.com>
Signed-off-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>
---
 net/mptcp/options.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)
diff mbox series

Patch

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;