Require token if the first packet is lost or reordered in order to
buffer the data coming from validated client only.

Add generated certificates to .gitignore

Introduce put_uint16_varint function

Remove unnecessary callback comments

Remove unused chrono include from debug.h

Replace goto in create_ssl_ctx with exit

This commit adds a static function named put_uint16_varint to reduce
some code duplication when putting some transport parameters.

chrono is used by generate_token and verify_token and was previously
indirectly via debug.h.

This commit updates the server's create_ssl_ctx use exit(EXIT_FAILURE)
instead of using a goto label.

The motivation of this is to be consistent with create_ssl_ctx in
client.cc.

Use TLS_client_method and TLS_server_method

Use ngtcp2_conn_state as type for state field

When compiling with the flag -Wswitch-enum there are a number of
warnings like the following:
ngtcp2_conn.c:7960:11: warning:
7 enumeration values not handled in switch:
  'NGTCP2_CS_CLIENT_INITIAL',
  'NGTCP2_CS_CLIENT_WAIT_HANDSHAKE',
  'NGTCP2_CS_CLIENT_TLS_HANDSHAKE_FAILED'... [-Wswitch]
  switch (conn->state) {

This commit adds a default clause to avoid this as they are reported as
errors on the CI server and failing the build.

This commit changes the TLS_method() used by the client and server to
use more specific TLS_client_method() and TLS_server_method().

The main difference between these two are ossl_statem_accept is
undefined for the client, and ossl_statem_connect is undefined for the
server:

IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, 0, 0,
                        TLS_server_method,
                        ossl_statem_accept,
                        ssl_undefined_function, TLSv1_2_enc_data)

IMPLEMENT_tls_meth_func(TLS_ANY_VERSION, 0, 0,
                        TLS_client_method,
                        ssl_undefined_function,
                        ossl_statem_connect, TLSv1_2_enc_data)

ossl_statem_accept and ossl_statem_connect are defined like this:

int ossl_statem_accept(SSL *s) {
    return state_machine(s, 1);
}
int ossl_statem_connect(SSL *s) {
    return state_machine(s, 0);
}

So they are both calling state_machine but with setting the server
parameter to 1 and 0 (for...

Move template.h into server.cc

Add Wireshark configuration steps

This commit suggests updating ngtcp2_conn's state field to be of type
ngtcp2_conn_state instead of type int.

This commit adds information about configuring Wireshark for analyzing
QUIC traffic.