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use hickory_proto::{
op::{Message, MessageType, ResponseCode},
rr::{record_type::RecordType, Name, RData, Record},
};
use std::{net::IpAddr, str::FromStr};
pub fn build_dns_response(mut request: Message, domain: &str, ip: IpAddr, ttl: u32) -> Result<Message, String> {
let record = match ip {
IpAddr::V4(ip) => {
let mut record = Record::with(Name::from_str(domain)?, RecordType::A, ttl);
record.set_data(Some(RData::A(ip.into())));
record
}
IpAddr::V6(ip) => {
let mut record = Record::with(Name::from_str(domain)?, RecordType::AAAA, ttl);
record.set_data(Some(RData::AAAA(ip.into())));
record
}
};
// We must indicate that this message is a response. Otherwise, implementations may not
// recognize it.
request.set_message_type(MessageType::Response);
request.add_answer(record);
Ok(request)
}
pub fn remove_ipv6_entries(message: &mut Message) {
message
.answers_mut()
.retain(|answer| !matches!(answer.data(), Some(RData::AAAA(_))));
}
pub fn extract_ipaddr_from_dns_message(message: &Message) -> Result<IpAddr, String> {
if message.response_code() != ResponseCode::NoError {
return Err(format!("{:?}", message.response_code()));
}
let mut cname = None;
for answer in message.answers() {
match answer.data().ok_or("DNS response not contains answer data")? {
RData::A(addr) => {
return Ok(IpAddr::V4((*addr).into()));
}
RData::AAAA(addr) => {
return Ok(IpAddr::V6((*addr).into()));
}
RData::CNAME(name) => {
cname = Some(name.to_utf8());
}
_ => {}
}
}
if let Some(cname) = cname {
return Err(cname);
}
Err(format!("{:?}", message.answers()))
}
pub fn extract_domain_from_dns_message(message: &Message) -> Result<String, String> {
let query = message.queries().first().ok_or("DnsRequest no query body")?;
let name = query.name().to_string();
Ok(name)
}
pub fn parse_data_to_dns_message(data: &[u8], used_by_tcp: bool) -> Result<Message, String> {
if used_by_tcp {
if data.len() < 2 {
return Err("invalid dns data".into());
}
let len = u16::from_be_bytes([data[0], data[1]]) as usize;
let data = data.get(2..len + 2).ok_or("invalid dns data")?;
return parse_data_to_dns_message(data, false);
}
let message = Message::from_vec(data).map_err(|e| e.to_string())?;
Ok(message)
}