DSA_get_ex_new_index, DSA_set_ex_data, DSA_get_ex_data

 #include <openssl/dsa.h>
 int DSA_get_ex_new_index(long argl, void *argp,
                CRYPTO_EX_new *new_func,
                CRYPTO_EX_dup *dup_func,
                CRYPTO_EX_free *free_func);
 int DSA_set_ex_data(DSA *d, int idx, void *arg);
 char *DSA_get_ex_data(DSA *d, int idx);

These functions handle application specific data in DSA structures. Their usage is identical to that of RSA_get_ex_new_index(), RSA_set_ex_data() and RSA_get_ex_data() as described in RSA_get_ex_new_index(3).

RSA_get_ex_new_index(3), dsa(3)

DSA_get_ex_new_index(), DSA_set_ex_data() and DSA_get_ex_data() are available since OpenSSL 0.9.5.