libssh2_channel_forward_cancel man page
libssh2_channel_forward_cancel — cancel a forwarded TCP port
int libssh2_channel_forward_cancel(LIBSSH2_LISTENER *listener);
listener - Forwarding listener instance as returned by libssh2_channel_forward_listen_ex(3)
Instruct the remote host to stop listening for new connections on a previously requested host/port.
Return 0 on success or negative on failure. It returns LIBSSH2_ERROR_EAGAIN when it would otherwise block. While LIBSSH2_ERROR_EAGAIN is a negative number, it isn't really a failure per se.
LIBSSH2_ERROR_ALLOC - An internal memory allocation call failed.
LIBSSH2_ERROR_SOCKET_SEND - Unable to send data on socket.