Up to this series, it was possible to add a "signal" MPTCP endpoint with
an IPv6 address and a port, or to directly request to send an ADD_ADDR
with a v6 address and a port, but the expected ADD_ADDR wasn't sent when
TCP timestamps was used for the connection.
In fact, such signalling option cannot be sent when TCP timestamps is
used due to a lack of option space: the limit is at 40 bytes, and, with
padding, TCP timestamps is taking 12 bytes, while an ADD_ADDR IPv6 +
port is taking 30 bytes. The selected solution here is to simply drop
the TCP timestamps option when such ADD_ADDR of 30 bytes needs to be
sent.
- Patches 1-3: small cleanups to avoid computing ADD/RM_ADDR twice.
- Patches 4-7: the new feature, controlled by a new sysctl knob.
- Patch 8: extra checks in the MPTCP Join selftests.
- Patches 9-15: A bunch of refactoring: renamed confusing helpers and
variables, and prevent future misused functions.
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Changes in v2:
- Rebased: some diff caused by commit a02a765bd5c2 ("mptcp: change
mptcp_established_options() to return opt_size") and commit
bd34fa025726 ("mptcp: add-addr: always drop other suboptions")
- Patch 4: Use READ_ONCE() to read sysctl data. (Eric)
- Patches 5-6: Avoid passing local variables' addresses to
mptcp_established_options not to force the compiler to use a stack
canary in this hot function, even for non-MPTCP flows. (Eric)
- Replaced previous patches 9-11 modifying selftests by a bunch of
pm related refactoring: patches 9-15.
- Link to v1: https://patch.msgid.link/20260601-net-next-mptcp-add-addr6-port-ts-v1-0-4fc25dfef62e@kernel.org
---
Matthieu Baerts (NGI0) (15):
mptcp: options: suboptions sizes can be negative
mptcp: pm: avoid computing rm_addr size twice
mptcp: pm: avoid computing add_addr size twice
mptcp: introduce add_addr_v6_port_drop_ts sysctl knob
tcp: allow mptcp to drop TS for some packets
mptcp: pm: drop TCP TS with ADD_ADDRv6 + port
selftests: mptcp: validate ADD_ADDRv6 + TS + port
selftests: mptcp: always check sent/dropped ADD_ADDRs
mptcp: pm: use for_each_subflow helper
mptcp: pm: rename add_entry structure to add_addr
mptcp: pm: uniform announced addresses helpers
mptcp: pm: remove add_ prefix from timer
mptcp: pm: make mptcp_pm_add_addr_send_ack static
mptcp: pm: avoid using del_timer directly
mptcp: options: rst: drop unused skb parameter
Documentation/networking/mptcp-sysctl.rst | 13 ++
include/net/mptcp.h | 13 +-
net/ipv4/tcp_output.c | 10 +-
net/mptcp/ctrl.c | 18 ++-
net/mptcp/options.c | 68 +++------
net/mptcp/pm.c | 191 ++++++++++++++----------
net/mptcp/pm_kernel.c | 22 +--
net/mptcp/pm_userspace.c | 6 +-
net/mptcp/protocol.h | 48 ++----
net/mptcp/subflow.c | 4 +-
tools/testing/selftests/net/mptcp/mptcp_join.sh | 83 +++++-----
11 files changed, 248 insertions(+), 228 deletions(-)
---
base-commit: bfa3d89cc15c09f7d1581c834a5ed725189ec19f
change-id: 20260601-net-next-mptcp-add-addr6-port-ts-40d8d74d8e20
Best regards,
--
Matthieu Baerts (NGI0) <matttbe@kernel.org>