DH shared key generation using Oakley groups.

[joseph k j]

hello everyone,

I am currently using the following functions,
 
   a = DH_new();
   DH_generate_parameters_ex(a, prime_len, generator, &cb );

here i see the prime generated is random, each time i call the function it genrerates a new prime.
but how is it possible for me to use predefined parameters, (esp prime)
ie i would like to use the oakley groups 1,2,5 (MODP).

is there a function like a= DH_group_get(<group descriptor>);

so that i dont need to generate a prime but use the prime defined in the group..
can anyone help me ..

Thanks a lot for any help.

wishes
ark