evan/protomask
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functional TCP

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This commit is contained in:
Evan Pratten 2023-07-16 21:29:45 -04:00
parent 7f53ef36d9
commit 02e2644d51
1 changed files with 46 additions and 9 deletions

55
src/nat/xlat/tcp.rs

@ -4,7 +4,8 @@ use pnet_packet::{
ip::IpNextHeaderProtocols, ip::IpNextHeaderProtocols,
ipv4::{self, Ipv4Packet, MutableIpv4Packet}, ipv4::{self, Ipv4Packet, MutableIpv4Packet},
ipv6::{Ipv6Packet, MutableIpv6Packet}, ipv6::{Ipv6Packet, MutableIpv6Packet},
Packet, tcp::TcpPacket, tcp::{self, MutableTcpPacket, TcpPacket},
Packet,
}; };
use crate::nat::packet::IpPacket; use crate::nat::packet::IpPacket;
@ -24,20 +25,43 @@ pub async fn proxy_tcp_packet<'a>(
// Parse the original packet's payload to extract UDP data // Parse the original packet's payload to extract UDP data
let tcp_packet = TcpPacket::new(original_packet.get_payload()) let tcp_packet = TcpPacket::new(original_packet.get_payload())
.ok_or_else(|| TcpProxyError::PacketTooShort(original_packet.get_payload().len()))?; .ok_or_else(|| TcpProxyError::PacketTooShort(original_packet.get_payload().len()))?;
log::debug!(
"Incoming TCP packet ports: {} -> {}",
tcp_packet.get_source(),
tcp_packet.get_destination()
);
log::debug!(
"Incoming TCP packet payload len: {}",
tcp_packet.payload().len()
);
// Construct a new output packet // Construct a new output packet
match (&original_packet, new_source, new_destination) { match (&original_packet, new_source, new_destination) {
// Translate IPv4(UDP) to IPv6(UDP) // Translate IPv4(UDP) to IPv6(UDP)
(IpPacket::V4(_), IpAddr::V6(new_source), IpAddr::V6(new_destination)) => { (IpPacket::V4(_), IpAddr::V6(new_source), IpAddr::V6(new_destination)) => {
// Construct translated TCP packet
let mut translated_tcp_packet =
MutableTcpPacket::owned(tcp_packet.packet().to_vec()).unwrap();
// Rewrite the checksum
translated_tcp_packet.set_checksum(0);
translated_tcp_packet.set_checksum(tcp::ipv6_checksum(
&translated_tcp_packet.to_immutable(),
&new_source,
&new_destination,
));
// Construct translated IP packet to wrap TCP packet
let mut output = let mut output =
MutableIpv6Packet::owned(vec![0u8; 40 + tcp_packet.packet().len()]).unwrap(); MutableIpv6Packet::owned(vec![0u8; 40 + translated_tcp_packet.packet().len()])
.unwrap();
output.set_version(6); output.set_version(6);
output.set_source(new_source); output.set_source(new_source);
output.set_destination(new_destination); output.set_destination(new_destination);
output.set_hop_limit(original_packet.get_ttl()); output.set_hop_limit(original_packet.get_ttl());
output.set_next_header(IpNextHeaderProtocols::Udp); output.set_next_header(IpNextHeaderProtocols::Tcp);
output.set_payload_length(tcp_packet.packet().len() as u16); output.set_payload_length(translated_tcp_packet.packet().len() as u16);
output.set_payload(tcp_packet.packet()); output.set_payload(translated_tcp_packet.packet());
Ok(IpPacket::V6( Ok(IpPacket::V6(
Ipv6Packet::owned(output.to_immutable().packet().to_vec()).unwrap(), Ipv6Packet::owned(output.to_immutable().packet().to_vec()).unwrap(),
)) ))
@ -45,16 +69,29 @@ pub async fn proxy_tcp_packet<'a>(
// Translate IPv6(UDP) to IPv4(UDP) // Translate IPv6(UDP) to IPv4(UDP)
(IpPacket::V6(_), IpAddr::V4(new_source), IpAddr::V4(new_destination)) => { (IpPacket::V6(_), IpAddr::V4(new_source), IpAddr::V4(new_destination)) => {
// Construct translated TCP packet
let mut translated_tcp_packet =
MutableTcpPacket::owned(tcp_packet.packet().to_vec()).unwrap();
// Rewrite the checksum
translated_tcp_packet.set_checksum(0);
translated_tcp_packet.set_checksum(tcp::ipv4_checksum(
&translated_tcp_packet.to_immutable(),
&new_source,
&new_destination,
));
// Construct translated IP packet to wrap TCP packet
let mut output = let mut output =
MutableIpv4Packet::owned(vec![0u8; 20 + tcp_packet.packet().len()]).unwrap(); MutableIpv4Packet::owned(vec![0u8; 20 + translated_tcp_packet.packet().len()]).unwrap();
output.set_version(4); output.set_version(4);
output.set_source(new_source); output.set_source(new_source);
output.set_destination(new_destination); output.set_destination(new_destination);
output.set_ttl(original_packet.get_ttl()); output.set_ttl(original_packet.get_ttl());
output.set_next_level_protocol(IpNextHeaderProtocols::Udp); output.set_next_level_protocol(IpNextHeaderProtocols::Tcp);
output.set_header_length(5); output.set_header_length(5);
output.set_total_length(20 + tcp_packet.packet().len() as u16); output.set_total_length(20 + translated_tcp_packet.packet().len() as u16);
output.set_payload(tcp_packet.packet()); output.set_payload(translated_tcp_packet.packet());
output.set_checksum(0); output.set_checksum(0);
output.set_checksum(ipv4::checksum(&output.to_immutable())); output.set_checksum(ipv4::checksum(&output.to_immutable()));
Ok(IpPacket::V4( Ok(IpPacket::V4(