[PATCH net 01/15] mptcp: pm: reuse ID 0 after delete and re-add

From: Matthieu Baerts (NGI0)
Date: Mon Aug 26 2024 - 11:59:53 EST


When the endpoint used by the initial subflow is removed and re-added
later, the PM has to force the ID 0, it is a special case imposed by the
MPTCP specs.

Note that the endpoint should then need to be re-added reusing the same
ID.

Fixes: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
net/mptcp/pm_netlink.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 3e4ad801786f..9ee68ab4665e 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -585,6 +585,11 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)

__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
msk->pm.add_addr_signaled++;
+
+ /* Special case for ID0: set the correct ID */
+ if (local.addr.id == msk->mpc_endpoint_id)
+ local.addr.id = 0;
+
mptcp_pm_announce_addr(msk, &local.addr, false);
mptcp_pm_nl_addr_send_ack(msk);

@@ -609,6 +614,11 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)

msk->pm.local_addr_used++;
__clear_bit(local.addr.id, msk->pm.id_avail_bitmap);
+
+ /* Special case for ID0: set the correct ID */
+ if (local.addr.id == msk->mpc_endpoint_id)
+ local.addr.id = 0;
+
nr = fill_remote_addresses_vec(msk, &local.addr, fullmesh, addrs);
if (nr == 0)
continue;

--
2.45.2