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Merge pull request #505 from theli-ua/v0.7.x 

Emit dns servers in DHCPv4 repr. Fixes #504
v0.7.x
Dario Nieuwenhuis 2021-06-27 08:42:34 +02:00 committed by GitHub
parent 450c5d8f87 0974b3c6be
commit b8a262cec2
1 changed files with 44 additions and 2 deletions
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46
src/wire/dhcpv4.rs
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@ -8,6 +8,8 @@ use crate::wire::arp::Hardware;
const DHCP_MAGIC_NUMBER: u32 = 0x63825363;
pub const MAX_DNS_SERVERS: usize = 3;
enum_with_unknown! {
/// The possible opcodes of a DHCP packet.
pub enum OpCode(u8) {
@ -680,7 +682,7 @@ pub struct Repr<'a> {
/// the client is interested in.
pub parameter_request_list: Option<&'a [u8]>,
/// DNS servers
pub dns_servers: Option<[Option<Ipv4Address>; 3]>,
pub dns_servers: Option<[Option<Ipv4Address>; MAX_DNS_SERVERS]>,
/// The maximum size dhcp packet the interface can receive
pub max_size: Option<u16>,
/// The DHCP IP lease duration, specified in seconds.
@ -700,6 +702,10 @@ impl<'a> Repr<'a> {
if self.router.is_some() { len += 6; }
if self.subnet_mask.is_some() { len += 6; }
if self.lease_duration.is_some() { len += 6; }
if let Some(dns_servers) = self.dns_servers {
len += 2;
len += dns_servers.iter().flatten().count() * core::mem::size_of::<u32>();
}
if let Some(list) = self.parameter_request_list { len += list.len() + 2; }
len
@ -777,7 +783,7 @@ impl<'a> Repr<'a> {
parameter_request_list = Some(data);
}
DhcpOption::Other {kind: field::OPT_DOMAIN_NAME_SERVER, data} => {
let mut servers = [None; 3];
let mut servers = [None; MAX_DNS_SERVERS];
for (server, chunk) in servers.iter_mut().zip(data.chunks(4)) {
*server = Some(Ipv4Address::from_bytes(chunk));
}
@ -842,6 +848,19 @@ impl<'a> Repr<'a> {
if let Some(duration) = self.lease_duration {
let tmp = options; options = DhcpOption::IpLeaseTime(duration).emit(tmp);
}
if let Some(dns_servers) = self.dns_servers {
const IP_SIZE: usize = core::mem::size_of::<u32>();
let mut servers = [0; MAX_DNS_SERVERS * IP_SIZE];
let data_len = dns_servers.iter().flatten()
.enumerate()
.inspect(|(i, ip)| {
servers[(i * IP_SIZE)..((i + 1) * IP_SIZE)]
.copy_from_slice(ip.as_bytes());
}).count() * IP_SIZE;
let option = DhcpOption::Other{ kind: field::OPT_DOMAIN_NAME_SERVER, data: &servers[..data_len] };
let tmp = options; options = option.emit(tmp);
}
if let Some(list) = self.parameter_request_list {
let option = DhcpOption::Other{ kind: field::OPT_PARAMETER_REQUEST_LIST, data: list };
let tmp = options; options = option.emit(tmp);
@ -1088,6 +1107,29 @@ mod test {
repr.emit(&mut packet).unwrap();
}
#[test]
fn test_emit_offer_dns() {
let repr = {
let mut repr = offer_repr();
repr.dns_servers = Some([
Some(Ipv4Address([163, 1, 74, 6])),
Some(Ipv4Address([163, 1, 74, 7])),
Some(Ipv4Address([163, 1, 74, 3]))]);
repr
};
let mut bytes = vec![0xa5; repr.buffer_len()];
let mut packet = Packet::new_unchecked(&mut bytes);
repr.emit(&mut packet).unwrap();
let packet = Packet::new_unchecked(&bytes);
let repr_parsed = Repr::parse(&packet).unwrap();
assert_eq!(repr_parsed.dns_servers, Some([
Some(Ipv4Address([163, 1, 74, 6])),
Some(Ipv4Address([163, 1, 74, 7])),
Some(Ipv4Address([163, 1, 74, 3]))]));
}
#[test]
fn test_emit_dhcp_option() {
static DATA: &[u8] = &[1, 3, 6];