diff mbox series

[net-next,4/4] mptcp: use "middlebox interference" RST when no DSS

Message ID 20241021-net-next-mptcp-misc-6-13-v1-4-1ef02746504a@kernel.org (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series mptcp: various small improvements | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch warning WARNING: line length of 84 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-10-22--00-00 (tests: 765)

Commit Message

Matthieu Baerts Oct. 21, 2024, 3:14 p.m. UTC 
From: Davide Caratti <dcaratti@redhat.com>

RFC8684 suggests use of "Middlebox interference (code 0x06)" in case of
fully established subflow that carries data at TCP level with no DSS
sub-option.

This is generally the case when mpext is NULL or mpext->use_map is 0:
use a dedicated value of 'mapping_status' and use it before closing the
socket in subflow_check_data_avail().

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/518
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/subflow.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 860903e0642255cf9efb39da9e24c39f6547481f..07352b15f145832572a4203ab4d0427c37675e94 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -971,7 +971,8 @@  enum mapping_status {
 	MAPPING_EMPTY,
 	MAPPING_DATA_FIN,
 	MAPPING_DUMMY,
-	MAPPING_BAD_CSUM
+	MAPPING_BAD_CSUM,
+	MAPPING_NODSS
 };
 
 static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
@@ -1128,8 +1129,9 @@  static enum mapping_status get_mapping_status(struct sock *ssk,
 			return MAPPING_EMPTY;
 		}
 
+		/* If the required DSS has likely been dropped by a middlebox */
 		if (!subflow->map_valid)
-			return MAPPING_INVALID;
+			return MAPPING_NODSS;
 
 		goto validate_seq;
 	}
@@ -1343,7 +1345,7 @@  static bool subflow_check_data_avail(struct sock *ssk)
 		status = get_mapping_status(ssk, msk);
 		trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue));
 		if (unlikely(status == MAPPING_INVALID || status == MAPPING_DUMMY ||
-			     status == MAPPING_BAD_CSUM))
+			     status == MAPPING_BAD_CSUM || status == MAPPING_NODSS))
 			goto fallback;
 
 		if (status != MAPPING_OK)
@@ -1396,7 +1398,9 @@  static bool subflow_check_data_avail(struct sock *ssk)
 			 * subflow_error_report() will introduce the appropriate barriers
 			 */
 			subflow->reset_transient = 0;
-			subflow->reset_reason = MPTCP_RST_EMPTCP;
+			subflow->reset_reason = status == MAPPING_NODSS ?
+						MPTCP_RST_EMIDDLEBOX :
+						MPTCP_RST_EMPTCP;
 
 reset:
 			WRITE_ONCE(ssk->sk_err, EBADMSG);