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UDP proxy works!

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This commit is contained in:
Evan Pratten 2023-07-16 21:10:08 -04:00
parent ab254122ce
commit 7f53ef36d9
1 changed files with 41 additions and 7 deletions
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48
src/nat/xlat/udp.rs
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@ -4,7 +4,7 @@ use pnet_packet::{
ip::IpNextHeaderProtocols,
ipv4::{self, Ipv4Packet, MutableIpv4Packet},
ipv6::{Ipv6Packet, MutableIpv6Packet},
udp::UdpPacket,
udp::{self, MutableUdpPacket, UdpPacket},
Packet,
};
@ -25,20 +25,38 @@ pub async fn proxy_udp_packet<'a>(
// Parse the original packet's payload to extract UDP data
let udp_packet = UdpPacket::new(original_packet.get_payload())
.ok_or_else(|| UdpProxyError::PacketTooShort(original_packet.get_payload().len()))?;
log::debug!("Incoming UDP packet ports: {} -> {}", udp_packet.get_source(), udp_packet.get_destination());
log::debug!("Incoming UDP packet payload len: {}", udp_packet.payload().len());
// Construct a new output packet
match (&original_packet, new_source, new_destination) {
// Translate IPv4(UDP) to IPv6(UDP)
(IpPacket::V4(_), IpAddr::V6(new_source), IpAddr::V6(new_destination)) => {
// Construct translated UDP packet
let mut translated_udp_packet =
MutableUdpPacket::owned(vec![0u8; 8 + udp_packet.payload().len()]).unwrap();
translated_udp_packet.set_source(udp_packet.get_source());
translated_udp_packet.set_destination(udp_packet.get_destination());
translated_udp_packet.set_length(8 + udp_packet.payload().len() as u16);
translated_udp_packet.set_payload(udp_packet.payload());
translated_udp_packet.set_checksum(0);
translated_udp_packet.set_checksum(udp::ipv6_checksum(
&translated_udp_packet.to_immutable(),
&new_source,
&new_destination,
));
// Construct translated IP packet to wrap UDP packet
let mut output =
MutableIpv6Packet::owned(vec![0u8; 40 + udp_packet.packet().len()]).unwrap();
MutableIpv6Packet::owned(vec![0u8; 40 + translated_udp_packet.packet().len()])
.unwrap();
output.set_version(6);
output.set_source(new_source);
output.set_destination(new_destination);
output.set_hop_limit(original_packet.get_ttl());
output.set_next_header(IpNextHeaderProtocols::Udp);
output.set_payload_length(udp_packet.packet().len() as u16);
output.set_payload(udp_packet.packet());
output.set_payload_length(translated_udp_packet.packet().len() as u16);
output.set_payload(translated_udp_packet.packet());
Ok(IpPacket::V6(
Ipv6Packet::owned(output.to_immutable().packet().to_vec()).unwrap(),
))
@ -46,16 +64,32 @@ pub async fn proxy_udp_packet<'a>(
// Translate IPv6(UDP) to IPv4(UDP)
(IpPacket::V6(_), IpAddr::V4(new_source), IpAddr::V4(new_destination)) => {
// Construct translated UDP packet
let mut translated_udp_packet =
MutableUdpPacket::owned(vec![0u8; 8 + udp_packet.payload().len()]).unwrap();
translated_udp_packet.set_source(udp_packet.get_source());
translated_udp_packet.set_destination(udp_packet.get_destination());
translated_udp_packet.set_length(8 + udp_packet.payload().len() as u16);
translated_udp_packet.set_payload(udp_packet.payload());
translated_udp_packet.set_checksum(0);
translated_udp_packet.set_checksum(udp::ipv4_checksum(
&translated_udp_packet.to_immutable(),
&new_source,
&new_destination,
));
// Construct translated IP packet to wrap UDP packet
let mut output =
MutableIpv4Packet::owned(vec![0u8; 20 + udp_packet.packet().len()]).unwrap();
MutableIpv4Packet::owned(vec![0u8; 20 + translated_udp_packet.packet().len()])
.unwrap();
output.set_version(4);
output.set_source(new_source);
output.set_destination(new_destination);
output.set_ttl(original_packet.get_ttl());
output.set_next_level_protocol(IpNextHeaderProtocols::Udp);
output.set_header_length(5);
output.set_total_length(20 + udp_packet.packet().len() as u16);
output.set_payload(udp_packet.packet());
output.set_total_length(20 + translated_udp_packet.packet().len() as u16);
output.set_payload(translated_udp_packet.packet());
output.set_checksum(0);
output.set_checksum(ipv4::checksum(&output.to_immutable()));
Ok(IpPacket::V4(