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refactor for better modularity

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This commit is contained in:
Xander Bil 2024-06-07 23:46:35 +02:00
parent 83fedebed6
commit 95ea1a434f
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GPG key ID: EC9706B54A278598
8 changed files with 233 additions and 179 deletions
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30
src/handlers/mod.rs Normal file
View file

@ -0,0 +1,30 @@
use crate::{
errors::DNSError,
structs::{Message, Opcode, RCODE},
};
use self::{query::QueryHandler, update::UpdateHandler};
mod query;
mod update;
pub trait ResponseHandler {
async fn handle(message: &Message, raw: &[u8]) -> Result<Message, DNSError>;
}
pub struct Handler {}
impl ResponseHandler for Handler {
async fn handle(message: &Message, raw: &[u8]) -> Result<Message, DNSError> {
match message.get_opcode() {
Ok(opcode) => match opcode {
Opcode::QUERY => QueryHandler::handle(&message, raw).await,
Opcode::UPDATE => UpdateHandler::handle(&message, raw).await,
},
Err(e) => Err(DNSError {
message: e.to_string(),
rcode: RCODE::FORMERR,
}),
}
}
}

35
src/handlers/query.rs Normal file
View file

@ -0,0 +1,35 @@
use crate::{
db::models::get_from_database,
errors::DNSError,
structs::{Message, RCODE},
};
use super::ResponseHandler;
pub(super) struct QueryHandler {}
impl ResponseHandler for QueryHandler {
async fn handle(message: &Message, _raw: &[u8]) -> Result<Message, DNSError> {
let mut response = message.clone();
response.header.arcount = 0; //TODO: fix this, handle unknown class values
for question in &message.question {
let answers = get_from_database(&question).await;
match answers {
Ok(rrs) => {
response.header.ancount = rrs.len() as u16;
response.answer.extend(rrs)
}
Err(e) => {
return Err(DNSError {
rcode: RCODE::NXDOMAIN,
message: e.to_string(),
})
}
}
}
Ok(response)
}
}

9
src/authenticate.rs → src/handlers/update/authenticate.rs
View file

@ -2,16 +2,15 @@ use std::env;
use reqwest::Error;
use crate::{
errors::AuthenticationError,
sig::{PublicKey, Sig},
};
use crate::errors::AuthenticationError;
use super::sig::{PublicKey, Sig};
type SSHKeys = Vec<String>;
type Result<T> = std::result::Result<T, AuthenticationError>;
pub async fn authenticate(sig: &Sig, zone: &Vec<String>) -> Result<bool> {
pub(super) async fn authenticate(sig: &Sig, zone: &Vec<String>) -> Result<bool> {
if zone.len() >= 4 {
let username = &zone[zone.len() - 4]; // Should match: username.users.zeus.gent
let public_keys = get_keys(username).await.map_err(|e| AuthenticationError {

132
src/handlers/update/mod.rs Normal file
View file

@ -0,0 +1,132 @@
use crate::{
db::models::{delete_from_database, insert_into_database},
errors::DNSError,
structs::{Class, Message, RRClass, RRType, Type, RCODE},
utils::vec_equal,
};
use self::sig::Sig;
use super::ResponseHandler;
mod authenticate;
mod sig;
pub(super) struct UpdateHandler {}
impl ResponseHandler for UpdateHandler {
async fn handle(message: &Message, raw: &[u8]) -> Result<Message, crate::errors::DNSError> {
let response = message.clone();
// Zone section (question) processing
if (message.header.qdcount != 1)
|| !matches!(message.question[0].qtype, Type::Type(RRType::SOA))
{
return Err(DNSError {
message: "Qdcount not one".to_string(),
rcode: RCODE::FORMERR,
});
}
// Check Zone authority
let zone = &message.question[0];
let zlen = zone.qname.len();
if !(zlen >= 2 && zone.qname[zlen - 1] == "gent" && zone.qname[zlen - 2] == "zeus") {
return Err(DNSError {
message: "Invalid zone".to_string(),
rcode: RCODE::NOTAUTH,
});
}
// Check Prerequisite TODO: implement this
//TODO: this code is ugly
let last = message.additional.last();
if last.is_some() && last.unwrap()._type == Type::Type(RRType::KEY) {
let sig = Sig::new(last.unwrap(), raw)?;
if !authenticate::authenticate(&sig, &zone.qname)
.await
.is_ok_and(|x| x)
{
return Err(DNSError {
message: "Unable to verify authentication".to_string(),
rcode: RCODE::NOTAUTH,
});
}
} else {
return Err(DNSError {
message: "No KEY record at the end of request found".to_string(),
rcode: RCODE::NOTAUTH,
});
}
// Update Section Prescan
for rr in &message.authority {
let rlen = rr.name.len();
// Check if rr has same zone
if rlen < zlen || !(vec_equal(&zone.qname, &rr.name[rlen - zlen..])) {
return Err(DNSError {
message: "RR has different zone from Question".to_string(),
rcode: RCODE::NOTZONE,
});
}
match (rr.class == Class::Class(RRClass::ANY) && (rr.ttl != 0 || rr.rdlength != 0))
|| (rr.class == Class::Class(RRClass::NONE) && rr.ttl != 0)
|| ![
Class::Class(RRClass::NONE),
Class::Class(RRClass::ANY),
zone.qclass.clone(),
]
.contains(&rr.class)
{
true => {
return Err(DNSError {
message: "RR has invalid rr,ttl or class".to_string(),
rcode: RCODE::FORMERR,
});
}
false => (),
}
}
for rr in &message.authority {
if rr.class == zone.qclass {
let _ = insert_into_database(&rr).await;
} else if rr.class == Class::Class(RRClass::ANY) {
if rr._type == Type::Type(RRType::ANY) {
if rr.name == zone.qname {
return Err(DNSError {
message: "Not yet implemented".to_string(),
rcode: RCODE::NOTIMP,
});
} else {
delete_from_database(&rr.name, None, Class::Class(RRClass::IN), None).await;
}
} else {
delete_from_database(
&rr.name,
Some(rr._type.clone()),
Class::Class(RRClass::IN),
None,
)
.await;
}
} else if rr.class == Class::Class(RRClass::NONE) {
if rr._type == Type::Type(RRType::SOA) {
continue;
}
delete_from_database(
&rr.name,
Some(rr._type.clone()),
Class::Class(RRClass::IN),
Some(rr.rdata.clone()),
)
.await;
}
}
Ok(response)
}
}

4
src/sig.rs → src/handlers/update/sig.rs
View file

@ -7,12 +7,12 @@ use crate::{
structs::{KeyRData, RR},
};
pub struct Sig {
pub(super) struct Sig {
raw_data: Vec<u8>,
key_rdata: KeyRData,
}
pub enum PublicKey {
pub(super) enum PublicKey {
ED25519(String),
}

4
src/main.rs
View file

@ -4,13 +4,13 @@ use dotenvy::dotenv;
use crate::resolver::resolver_listener_loop;
mod authenticate;
mod db;
mod errors;
mod handlers;
mod message;
mod parser;
mod reader;
mod resolver;
mod sig;
mod structs;
mod utils;

12
src/message.rs Normal file
View file

@ -0,0 +1,12 @@
use crate::structs::{Message, Opcode, RCODE};
impl Message {
pub fn set_response(&mut self, rcode: RCODE) {
self.header.flags = (self.header.flags | 0b1_0000_1_0_0_0_000_0000 | rcode as u16)
& 0b1_1111_1_0_1_0_111_1111
}
pub fn get_opcode(&self) -> Result<Opcode, String> {
Opcode::try_from((self.header.flags & 0b0111100000000000) >> 11)
}
}

174
src/resolver.rs
View file

@ -4,158 +4,14 @@ use std::sync::Arc;
use tokio::net::UdpSocket;
use crate::authenticate::authenticate;
use crate::db::models::{delete_from_database, get_from_database, insert_into_database};
use crate::errors::{DNSError, ParseError};
use crate::errors::ParseError;
use crate::handlers::{Handler, ResponseHandler};
use crate::parser::FromBytes;
use crate::reader::Reader;
use crate::sig::Sig;
use crate::structs::{Class, Header, Message, Opcode, RRClass, RRType, Type, RCODE};
use crate::utils::vec_equal;
use crate::structs::{Header, Message, RCODE};
const MAX_DATAGRAM_SIZE: usize = 4096;
fn set_response_flags(flags: &u16, rcode: RCODE) -> u16 {
(flags | 0b1_0000_1_0_0_0_000_0000 | rcode as u16) & 0b1_1111_1_0_1_0_111_1111
}
fn get_opcode(flags: &u16) -> Result<Opcode, String> {
Opcode::try_from((flags & 0b0111100000000000) >> 11)
}
async fn handle_query(message: &Message) -> Result<Message, DNSError> {
let mut response = message.clone();
response.header.arcount = 0; //TODO: fix this, handle unknown class values
for question in &message.question {
let answers = get_from_database(&question).await;
match answers {
Ok(rrs) => {
response.header.ancount = rrs.len() as u16;
response.answer.extend(rrs)
}
Err(e) => {
return Err(DNSError {
rcode: RCODE::NXDOMAIN,
message: e.to_string(),
})
}
}
}
Ok(response)
}
async fn handle_update(message: &Message, bytes: &[u8]) -> Result<Message, DNSError> {
let response = message.clone();
// Zone section (question) processing
if (message.header.qdcount != 1)
|| !matches!(message.question[0].qtype, Type::Type(RRType::SOA))
{
return Err(DNSError {
message: "Qdcount not one".to_string(),
rcode: RCODE::FORMERR,
});
}
// Check Zone authority
let zone = &message.question[0];
let zlen = zone.qname.len();
if !(zlen >= 2 && zone.qname[zlen - 1] == "gent" && zone.qname[zlen - 2] == "zeus") {
return Err(DNSError {
message: "Invalid zone".to_string(),
rcode: RCODE::NOTAUTH,
});
}
// Check Prerequisite TODO: implement this
//TODO: this code is ugly
let last = message.additional.last();
if last.is_some() && last.unwrap()._type == Type::Type(RRType::KEY) {
let sig = Sig::new(last.unwrap(), bytes)?;
if !authenticate(&sig, &zone.qname).await.is_ok_and(|x| x) {
return Err(DNSError {
message: "Unable to verify authentication".to_string(),
rcode: RCODE::NOTAUTH,
});
}
} else {
return Err(DNSError {
message: "No KEY record at the end of request found".to_string(),
rcode: RCODE::NOTAUTH,
});
}
// Update Section Prescan
for rr in &message.authority {
let rlen = rr.name.len();
// Check if rr has same zone
if rlen < zlen || !(vec_equal(&zone.qname, &rr.name[rlen - zlen..])) {
return Err(DNSError {
message: "RR has different zone from Question".to_string(),
rcode: RCODE::NOTZONE,
});
}
if (rr.class == Class::Class(RRClass::ANY) && (rr.ttl != 0 || rr.rdlength != 0))
|| (rr.class == Class::Class(RRClass::NONE) && rr.ttl != 0)
|| ![
Class::Class(RRClass::NONE),
Class::Class(RRClass::ANY),
zone.qclass.clone(),
]
.contains(&rr.class)
{
return Err(DNSError {
message: "RR has invalid rr,ttl or class".to_string(),
rcode: RCODE::FORMERR,
});
}
}
for rr in &message.authority {
if rr.class == zone.qclass {
let _ = insert_into_database(&rr).await;
} else if rr.class == Class::Class(RRClass::ANY) {
if rr._type == Type::Type(RRType::ANY) {
if rr.name == zone.qname {
return Err(DNSError {
message: "Not yet implemented".to_string(),
rcode: RCODE::NOTIMP,
});
} else {
delete_from_database(&rr.name, None, Class::Class(RRClass::IN), None).await;
}
} else {
delete_from_database(
&rr.name,
Some(rr._type.clone()),
Class::Class(RRClass::IN),
None,
)
.await;
}
} else if rr.class == Class::Class(RRClass::NONE) {
if rr._type == Type::Type(RRType::SOA) {
continue;
}
delete_from_database(
&rr.name,
Some(rr._type.clone()),
Class::Class(RRClass::IN),
Some(rr.rdata.clone()),
)
.await;
}
}
Ok(response)
}
fn handle_parse_error(bytes: &[u8], err: ParseError) -> Message {
eprintln!("{}", err);
let mut reader = Reader::new(bytes);
@ -172,41 +28,31 @@ fn handle_parse_error(bytes: &[u8], err: ParseError) -> Message {
header.ancount = 0;
header.nscount = 0;
header.arcount = 0;
header.flags = set_response_flags(&header.flags, RCODE::FORMERR);
Message {
let mut message = Message {
header,
question: vec![],
answer: vec![],
authority: vec![],
additional: vec![],
}
};
message.set_response(RCODE::FORMERR);
message
}
async fn get_response(bytes: &[u8]) -> Message {
let mut reader = Reader::new(bytes);
match Message::from_bytes(&mut reader) {
Ok(mut message) => match get_opcode(&message.header.flags) {
Ok(opcode) => {
let result = match opcode {
Opcode::QUERY => handle_query(&message).await,
Opcode::UPDATE => handle_update(&message, bytes).await,
};
match result {
Ok(mut message) => match Handler::handle(&message, bytes).await {
Ok(mut response) => {
response.header.flags =
set_response_flags(&response.header.flags, RCODE::NOERROR);
response.set_response(RCODE::NOERROR);
response
}
Err(e) => {
eprintln!("{}", e.to_string());
message.header.flags = set_response_flags(&message.header.flags, e.rcode);
message.set_response(e.rcode);
message
}
}
}
Err(_) => todo!(),
},
Err(err) => handle_parse_error(bytes, err),
}