mptcp: infinite mapping receiving

This patch adds the infinite mapping receiving logic. When the infinite
mapping is received, set the map_data_len of the subflow to 0.

In subflow_check_data_avail(), only reset the subflow when the map_data_len
of the subflow is non-zero.

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliang.tang@suse.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/subflow.c b/net/mptcp/subflow.c
index 31dcb55..30ffb00 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1006,7 +1006,9 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
 
        data_len = mpext->data_len;
        if (data_len == 0) {
+               pr_debug("infinite mapping received");
                MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
+               subflow->map_data_len = 0;
                return MAPPING_INVALID;
        }
 
@@ -1220,7 +1222,7 @@ fallback:
                        return true;
                }
 
-               if (subflow->mp_join || subflow->fully_established) {
+               if ((subflow->mp_join || subflow->fully_established) && subflow->map_data_len) {
                        /* fatal protocol error, close the socket.
                         * subflow_error_report() will introduce the appropriate barriers
                         */