From 8545e2232724aa22cf4558a54266de08ae8cc426 Mon Sep 17 00:00:00 2001
From: Patrick <patrick@failmail.dev>
Date: Tue, 31 Dec 2024 17:47:56 +0100
Subject: [PATCH] feat: relay packets

---
 src/main.rs | 54 ++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 47 insertions(+), 7 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 50cb9d0..febc13d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,7 @@
 const ADDR: Ipv4Addr = Ipv4Addr::new(224, 0, 0, 251);
 use color_eyre::{eyre::bail, Result};
 use pnet::datalink::{interfaces, NetworkInterface};
+use pnet::ipnetwork::IpNetwork::{V4, V6};
 use regex::Regex;
 use simple_dns::Packet;
 use socket2::{Domain, Protocol, Socket, Type};
@@ -10,11 +11,11 @@ use std::{
 };
 use tokio::net::UdpSocket;
 
-fn get_iface(from: &SocketAddr, ifaces: &Vec<&NetworkInterface>) -> Result<String> {
+fn get_iface(from: &SocketAddr, ifaces: &Vec<Iface>) -> Result<String> {
     for i in ifaces {
-        for ip in i.ips.iter() {
+        for ip in i.iface.ips.iter() {
             if ip.contains(from.ip()) {
-                return Ok(i.name.clone());
+                return Ok(i.iface.name.clone());
             }
         }
     }
@@ -39,12 +40,23 @@ struct Rule {
     allow_answers: Regex,
 }
 
+struct Iface {
+    iface: NetworkInterface,
+    socket: socket2::Socket,
+}
+
 #[tokio::main]
 async fn main() -> Result<()> {
     let mut rules = Vec::new();
     rules.push(Rule {
-        from: Regex::new("lan01")?,
-        to: "lan01".to_string(),
+        from: Regex::new("lan-home")?,
+        to: "lan-services".to_string(),
+        allow_answers: Regex::new(".*")?,
+        allow_questions: Regex::new(".*")?,
+    });
+    rules.push(Rule {
+        from: Regex::new("lan-services")?,
+        to: "lan-home".to_string(),
         allow_answers: Regex::new(".*")?,
         allow_questions: Regex::new(".*")?,
     });
@@ -64,13 +76,34 @@ async fn main() -> Result<()> {
         .filter(|x| {
             x.is_up() && !x.is_loopback() && !x.ips.is_empty() && iface_reg.is_match(&x.name)
         })
-        .collect();
-    println!("{:?}", interfaces);
+        .map(|x| -> Result<Iface> {
+            let socket = Socket::new(Domain::IPV4, Type::DGRAM, Some(Protocol::UDP))?;
+            socket.set_reuse_address(true)?;
+            socket.set_reuse_port(true)?;
+            for addr in &x.ips {
+                if let V4(addr) = addr {
+                    let sock_addr = SocketAddrV4::new(addr.ip(), 5353).into();
+                    socket.bind(&sock_addr)?;
+                }
+            }
+            Ok(Iface {
+                iface: x.clone(),
+                socket,
+            })
+        })
+        .collect::<Result<Vec<_>>>()?;
+    //println!("{:?}", interfaces);
     let mut buf = [0; 1024];
     let socket = UdpSocket::from_std(socket.into())?;
     loop {
         match socket.recv_from(&mut buf).await {
             Ok((_l, from)) => {
+                if interfaces
+                    .iter()
+                    .any(|x| x.iface.ips.iter().any(|y| y.ip() == from.ip()))
+                {
+                    continue;
+                }
                 let packet = Packet::parse(&buf)?;
                 //println!("{:?} {:?}\n", from, packet);
                 let iface = match get_iface(&from, &interfaces) {
@@ -97,6 +130,13 @@ async fn main() -> Result<()> {
                 }
                 out.remove(&iface);
                 println!("relaying packet to {:?}", out);
+                for i in &interfaces {
+                    if out.contains(&i.iface.name) {
+                        println!("sending packet on {}", i.iface.name);
+                        let sock_addr = SocketAddrV4::new(ADDR, 5353).into();
+                        i.socket.send_to(&buf, &sock_addr)?;
+                    }
+                }
                 // socket.send_to(&buf, addr);
             }
             Err(_) => todo!(),