tlsext_extension_seen
if (!tlsext_extension_seen(s, TLSEXT_TYPE_supported_groups)) {
tlsext_extension_seen(s, TLSEXT_TYPE_key_share));
int tlsext_extension_seen(SSL *s, uint16_t);
if (tlsext_extension_seen(s, TLSEXT_TYPE_pre_shared_key)) {
if (!tlsext_extension_seen(s,
if (!tlsext_extension_seen(s, TLSEXT_TYPE_signature_algorithms))
if (!tlsext_extension_seen(s, TLSEXT_TYPE_supported_groups))
if (tlsext_extension_seen(s, TLSEXT_TYPE_supported_groups) !=
tlsext_extension_seen(s, TLSEXT_TYPE_key_share))