mptcp: add deny_join_id0 in mptcp_options_received

This patch added a new flag named deny_join_id0 in struct
mptcp_options_received. Set it when MP_CAPABLE with the flag
MPTCP_CAP_DENYJOIN_ID0 is received.

Also add a new flag remote_deny_join_id0 in struct mptcp_pm_data. When the
flag deny_join_id0 is set, set this remote_deny_join_id0 flag.

In mptcp_pm_create_subflow_or_signal_addr, if the remote_deny_join_id0 flag
is set, and the remote address id is zero, stop this connection.

Suggested-by: Florian Westphal <fw@strlen.de>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index f2326f6..f4eaa5f 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -138,7 +138,8 @@ struct mptcp_options_received {
 		mp_prio : 1,
 		echo : 1,
 		csum_reqd : 1,
-		backup : 1;
+		backup : 1,
+		deny_join_id0 : 1;
 	u32	token;
 	u32	nonce;
 	u64	thmac;
@@ -193,6 +194,7 @@ struct mptcp_pm_data {
 	bool		work_pending;
 	bool		accept_addr;
 	bool		accept_subflow;
+	bool		remote_deny_join_id0;
 	u8		add_addr_signaled;
 	u8		add_addr_accepted;
 	u8		local_addr_used;