This adds support for DTLS1.2 ciphersuite header as sent by anyconnect
clients.
Resolves#188Resolves#193
Signed-off-by: Nikos Mavrogiannopoulos <nmav@gnutls.org>
That is, if the header contains "android" or "apple-ios" mark it as
a mobile client. The header X-AnyConnect-Identifier-DeviceType is only
considered for logging purposes and appended to the user-agent name
if present.
Disable MTU discovery when not requested, set the minimum packet size
to 1280 for IPv6 and 800 bytes for IPv4. When MTU discovery fails to
calculate an MTU over the minimum, it disables itself and ocserv will rely
on packet fragmentation. This also enhances DTLS connection detection
(due to MTU issues), by setting the DPD packet size to equal to the current
data MTU.
