man: mptcp: clarify the 'ID' parameter

Explain the range (u8), and the special case for ID 0.

The endpoints here are for all the connections, while the ID 0 is a
special case per connection, depending on the source address used by the
initial subflow. This ID 0 can then not be used for the global
endpoints.

Acked-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/man/man8/ip-mptcp.8 b/man/man8/ip-mptcp.8
index 4c1161fef06192d5768504f8e3608b5acccf59ad..e4a55f6c5a787cbd1dbe9048c64684d818ee3562 100644 (file)
--- a/man/man8/ip-mptcp.8
+++ b/man/man8/ip-mptcp.8
@@ -148,7 +148,11 @@ expected behavior.
 
 .TP
 .IR ID
-is a unique numeric identifier for the given endpoint
+is a unique numeric identifier, between 0 and 255, for the given endpoint. It is
+not possible to add endpoints with ID 0, because this special ID is reserved for
+the initial subflow. For rules linked to the initial subflow, the path-manager
+will look at endpoints matching the same address, and port if set, ignoring the
+ID.
 
 .TP
 .BR signal