pcr_protocol
session = pipex_lookup_by_session_id_locked(req->pcr_protocol,
pxi = pppx_if_find_locked(pxd, req->pcr_session_id, req->pcr_protocol);
req.pcr_protocol = PIPEX_PROTO_PPPOE;
req.pcr_protocol = PIPEX_PROTO_PPTP;
req.pcr_protocol = PIPEX_PROTO_L2TP;