l2tp: Implement peer authentication

Send the Challenge AVP in SCCRP messages and check for the Challenge
Response AVP in SCCCN.
This patch adds two functions:
  -l2tp_tunnel_genchall() generates the Challenge, stores it in the
   tunnel structure and adds the AVP in the packet to be sent.
  -l2tp_tunnel_checkchallresp() reads a Challenge Response, computes
   the expected response using the Challenge stored in the tunnel
   structure and finally checks if both responses match.

These two functions are meant to be used in the upcoming implementation
of SCCRQ message sending and SCCRP message reception.

Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>

0 files changed, 0 insertions, 0 deletions