This patch contains 2 enhancements to support operation of mpd 5.5 as an L2TP Tunnel Switch (LTS).
Primarily, it adds proxy CHAP authentication. If an incoming L2TP session provides proxy authentication attributes (and you have specified "set l2tp enable proxychap"), then MPD will use these to perform authentication before LCP is started. If the authentication method (e.g. RADIUS server) returns a repeater action then the session will be forwarded immediately without MPD needing to perform any LCP negotiation. If the authentication fails or does not yield a 'forward' or 'drop' action then local LCP negotiation and authentication will occur.
Secondly, this patch ensures that the RX and TX connect speed information provided by the LAC for an incoming L2TP sessions is forwarded on when MPD repeats this session to another L2TP session.