DH_METHOD
const DH_METHOD *DH_OpenSSL(void);
void DH_set_default_method(const DH_METHOD *meth);
const DH_METHOD *DH_get_default_method(void);
int DH_set_method(DH *dh, const DH_METHOD *meth);
static const DH_METHOD dh_ossl = {
const DH_METHOD *
static const DH_METHOD *default_DH_method = NULL;
DH_set_default_method(const DH_METHOD *meth)
const DH_METHOD *
DH_set_method(DH *dh, const DH_METHOD *meth)
const DH_METHOD *mtmp;
const DH_METHOD *meth;