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-rw-r--r--net/mptcp/options.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index ab054c389a5f..7345f28f3de1 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1267,8 +1267,27 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
const struct sock *ssk = (const struct sock *)tp;
struct mptcp_subflow_context *subflow;
- /* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,
- * see mptcp_established_options*()
+ /* Which options can be used together?
+ *
+ * X: mutually exclusive
+ * O: often used together
+ * C: can be used together in some cases
+ * P: could be used together but we prefer not to (optimisations)
+ *
+ * Opt: | MPC | MPJ | DSS | ADD | RM | PRIO | FAIL | FC |
+ * ------|------|------|------|------|------|------|------|------|
+ * MPC |------|------|------|------|------|------|------|------|
+ * MPJ | X |------|------|------|------|------|------|------|
+ * DSS | X | X |------|------|------|------|------|------|
+ * ADD | X | X | P |------|------|------|------|------|
+ * RM | C | C | C | P |------|------|------|------|
+ * PRIO | X | C | C | C | C |------|------|------|
+ * FAIL | X | X | C | X | X | X |------|------|
+ * FC | X | X | X | X | X | X | X |------|
+ * RST | X | X | X | X | X | X | O | O |
+ * ------|------|------|------|------|------|------|------|------|
+ *
+ * The same applies in mptcp_established_options() function.
*/
if (likely(OPTION_MPTCP_DSS & opts->suboptions)) {
struct mptcp_ext *mpext = &opts->ext_copy;