Add DTLS record header parsing, different client hello format and add
HelloVerifyRequest message type.
Add code to d1_pkt.c to send message headers to the message callback.
(cherry picked from commit 890f2f8b92b385ef3898cdb4a15a071ffcf8107f)
Conflicts:
ssl/ssl_locl.h
Add correct flags for DTLS 1.2, update s_server and s_client to handle
DTLS 1.2 methods.
Currently no support for version negotiation: i.e. if client/server selects
DTLS 1.2 it is that or nothing.
(cherry picked from commit c3b344e36a088283731b4f65a70e85b100f55686)
Conflicts:
apps/s_server.c
Use the enc_flags field to determine whether we should use explicit IV,
signature algorithms or SHA256 default PRF instead of hard coding which
versions support each requirement.
(cherry picked from commit cbd64894ec687c6f37d8e43c16dff78e63f6be87)
Conflicts:
ssl/ssl_locl.h
