dsa_cb
ASN1_SEQUENCE_cb(DSAPrivateKey, dsa_cb) = {
ASN1_SEQUENCE_cb(DSAparams, dsa_cb) = {
ASN1_SEQUENCE_cb(DSAPublicKey, dsa_cb) = {
BN_GENCB_set(cb, dsa_cb, NULL);
static int dsa_cb(int p, int n, BN_GENCB *arg);