Documentation is unclear on how vendor specific attributes are handled

[Kilobyte22]

The documentation does not specify how vendor specific attributes are encoded/accessed. In Particular RFC2865 specifies a format for encoding multiple attributes by a single vendor in a single Attribute 26. I do not see how i would get those.

[ivanovuri]

Hi friend,
Looks like library simply misses this logic and to create VSA containing reply we should craft packet manually.
To create this type of reply:

We need something like this:

fn hardcode_bytes_vsa() -> Vec<u8> {
    // let avp_type = 26 as u8;
    // let avp_length = 23 as u8;
    let mut avp_vendor_id = 4874_i32.to_be_bytes().to_vec();
    let vsa_type = 65 as u8;
    let vsa_length = 17 as u8;
    let vsa_tag = 5 as u8;
    let mut vsa_usa = "bar(1000,5441)".as_bytes().to_vec();

    let mut vsa: Vec<u8> = Vec::new();

    vsa.append(&mut avp_vendor_id);
    vsa.push(vsa_type);
    vsa.push(vsa_length);
    vsa.push(vsa_tag);
    vsa.append(&mut vsa_usa);

    vsa
}

After that construct with the help of from_bytes function:

let vsa = AVP::from_bytes(VENDOR_SPECIFIC_TYPE, &hardcode_bytes_vsa());
_ = p.add(vsa);

Please note that you should omit type and length values. Type is specified as first parameter and length is calculated automatically.