add README and fix some todos

README.md

@@ -0,0 +1,83 @@
+# Zeus (Domain) Name Server
+
+Is implementation of an authoritative DNS server.
+
+It gives all users who have a [Zauth](https://zauth.zeus.gent) account an own domain: `username.users.zeus.gent`.
+
+## General Information
+
+Creating/Updating your DNS records is only possible using dynamic DNS updating (DDNS, rfc2136). 
+It's an extension of DNS that lets you update your DNS records using the DNS protocol.
+
+ZNS authenticates these update requests using SIG(0) (rfc2931). 
+This is another extension of DNS that defines a signature record. It is appended to the query and contains the signature of the original query and 
+some other information like expiration time to prevent replay attacks.
+
+The signature is created with the private key of the signer and validated on the server with the corresponding public key.
+ZNS has 2 methods of validating the signature:
+- Using your SSH Keys in [Zauth](https://zauth.zeus.gent) 
+- Using a [DNSKEY record](https://datatracker.ietf.org/doc/html/rfc4034#section-2)
+
+
+## User Guide
+
+How to add an `A` record to `<your zauth username>.users.zeus.gent`.
+
+### Step 1
+
+Create an SSH key pair (or use an existing one). Currently, only ED25519 and RSA SSH key types are supported.
+Add the public key to your Zauth account.
+
+### Step 2
+
+The (most) painless way for sending DNS update queries is using the `nsupdate` program.
+With `nsupdate -k keys`, you can pass it your keys. But `nsupdate` expects your keys to have a certain format, so it won't accept the OPENSSH private key format.
+That's why there is a CLI (`zns-cli`) available that converts the OPENSSH private key format and creates `.key` and `.private` files corresponding with your public and private keys.
+And with some more info like the update ZONE (`username.users.zeus.gent`), the signing algorithm (ED25519 or RSA), ...
+
+Execute:
+
+```sh
+zns-cli --key <path to private ssh key> --username <zauth username>
+```
+
+Now you can run `nsupdate -k Kdns.private`.
+
+```
+> zone username.users.zeus.gent
+> update add username.users.zeus.gent 300 A <ip address>
+> send
+```
+
+This will add an A record to `username.users.zeus.gent`. 
+The message will be signed with the private key, and the server will try to validate by trying to find a valid public SSH key from your Zauth account. Matching the `username` given in the zone.
+The default expiration time with `nsupdate` is 5 minutes.
+
+That's it... not that hard, is it?
+
+### Step 3 (Optional)
+
+It is also possible to put your public key in a DNSKEY record instead of Zauth. In the previous step, `zns-cli` also generated a `.key` file. 
+This contains a DNSKEY resource record you can add to your zone using `nsupdate`. Now the signature can be validated directly using this record.
+
+It's also possible to directly generate a DNSKEY record key pair using `dnssec-keygen`.
+
+## Server Setup Guide
+
+There are three crates available at the root of the repo.
+
+`zns` is a library which is both used by `zns-cli` and `zns-daemon`.
+`zns-daemon` is the server that handles DNS queries.
+
+The following environment variables should be set (or stored in a `.env` file):
+```
+DATABASE_URL=postgres://zns@localhost/zns
+ZAUTH_URL="https://zauth.zeus.gent"
+ZONE="users.zeus.gent"
+```
+
+Optional: `ZNS_ADDRESS` and `ZNS_PORT`.
+
+After setting `DATABASE_URL`, create the database and run the migrations with `diesel migration run`.
+
+It's quite possible that something is not conform to an RFC, creating an issue is appreciated.

zns-cli/src/main.rs

@@ -1,5 +1,5 @@
 use base64::prelude::*;
-use num_bigint::{BigInt, BigUint};
+use num_bigint::BigUint;
 use num_traits::FromPrimitive;
 use std::error::Error;
 use std::fs::{self, File};
@@ -76,7 +76,7 @@ fn read_bytes(reader: &mut Reader) -> Result<Vec<u8>, ZNSError> {
 
 impl KeyTransformer for Ed25519KeyPair {
     fn from_openssh(reader: &mut Reader) -> Result<Self, ZNSError> {
-        // public key parts
+        // public key parts//TODO: change to SIG
         let length = reader.read_u32()?;
         reader.read(length as usize)?;
 
@@ -259,6 +259,7 @@ impl KeyTransformer for OpenSSHKey {
 
 const OPENSSH_START: &str = "-----BEGIN OPENSSH PRIVATE KEY-----";
 const OPENSSH_END: &str = "-----END OPENSSH PRIVATE KEY-----";
+const FILENAME: &str = "Kdns";
 
 fn ssh_to_dnskey(file_content: &str, username: &str) -> Result<(), Box<dyn Error>> {
     if !file_content.starts_with(OPENSSH_START) || !file_content.ends_with(OPENSSH_END) {
@@ -277,8 +278,8 @@ fn ssh_to_dnskey(file_content: &str, username: &str) -> Result<(), Box<dyn Error
     let mut reader = Reader::new(&bin);
     let key = OpenSSHKey::from_openssh(&mut reader)?;
 
-    let mut file_private = File::create("Kdns.private")?;
-    let mut file_public = File::create("Kdns.key")?;
+    let mut file_private = File::create(format!("{}.private", FILENAME))?;
+    let mut file_public = File::create(format!("{}.key", FILENAME))?;
 
     let (private, public) = key.to_dnskey(username);
     file_private.write(private.as_bytes())?;
@@ -292,7 +293,10 @@ fn main() {
 
     match fs::read_to_string(args.key) {
         Ok(contents) => match ssh_to_dnskey(contents.trim(), &args.username) {
-            Ok(()) => println!("Success"),
+            Ok(()) => println!(
+                "Successfully written {}.private and {}.key",
+                FILENAME, FILENAME
+            ),
             Err(error) => eprintln!("{}", error),
         },
         Err(error) => eprintln!("{}", error),

zns-daemon/src/handlers/update/mod.rs

@@ -51,7 +51,7 @@ impl ResponseHandler for UpdateHandler {
 
         //TODO: this code is ugly
         let last = message.additional.last();
-        if last.is_some() && last.unwrap()._type == Type::Type(RRType::KEY) {
+        if last.is_some() && last.unwrap()._type == Type::Type(RRType::SIG) {
             let sig = Sig::new(last.unwrap(), raw)?;
 
             if !authenticate::authenticate(&sig, &zone.qname, connection)

zns/src/structs.rs

@@ -11,7 +11,7 @@ pub enum Type {
 pub enum RRType {
     A = 1,
     SOA = 6,
-    KEY = 24, //TODO: change to SIG
+    SIG = 24,
     DNSKEY = 48,
     OPT = 41,
     ANY = 255,