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