From be92fc9d6fd534265a1efdcffdc68b371629629b Mon Sep 17 00:00:00 2001
From: Maxime Van Hees <maxime.vanhees@ugent.be>
Date: Tue, 23 May 2023 09:51:46 +0000
Subject: [PATCH] further ipv6 impl

---
 src/main.rs       |  2 ++
 src/node_setup.rs | 28 +++++++++++++++++++---------
 src/x25519.rs     |  2 +-
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 71b07d8..ef803c1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -37,6 +37,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
 
     // Generate the node's IPv6 address from its public key
     let node_addr = x25519::generate_addr_from_pubkey(&node_keypair.1);
+    println!("Node address: {}", node_addr);
 
     // Create TUN interface and add static route
     let node_tun = match node_setup::setup_node(node_addr).await {
@@ -77,6 +78,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
 
     // Read packets from the TUN interface (originating from the kernel) and send them to the router
     // Note: we will never receive control packets from the kernel, only data packets
+    // filter out packets that are not destined for 200::/7
     {
         let router = router.clone();
         let node_tun = node_tun.clone();
diff --git a/src/node_setup.rs b/src/node_setup.rs
index 3180f13..4b65a9f 100644
--- a/src/node_setup.rs
+++ b/src/node_setup.rs
@@ -37,32 +37,30 @@ pub async fn retrieve_tun_link_index(handle: Handle) -> Result<u32, Box<dyn std:
 }
 
 // Add address to TUN interface
-pub async fn add_address(handle: Handle, addr: Ipv6Addr) -> Result<(), Box<dyn std::error::Error>> {
-    let link_index = retrieve_tun_link_index(handle.clone()).await?;
+pub async fn add_address(handle: Handle, addr: Ipv6Addr, link_index: u32) -> Result<u32, Box<dyn std::error::Error>> {
     // add address to tun interface
     handle
         .address()
         .add(
             link_index,
             IpAddr::V6(addr),
-            7,
+            64,
         )
         .execute()
         .await?;
 
-    Ok(())
+    Ok(link_index)
 }
 
 
 // Adding route to TUN interface
-pub async fn add_route(handle: Handle) -> Result<(), Box<dyn std::error::Error>> {
-    let link_index = retrieve_tun_link_index(handle.clone()).await?;
+pub async fn add_route(handle: Handle, link_index: u32) -> Result<(), Box<dyn std::error::Error>> {
     // add route to tun interface
     let route = handle.route();
     route
         .add()
         .v6()
-        .destination_prefix(Ipv6Addr::new(0x200, 0, 0, 0, 0, 0, 0, 0), 7)
+        .destination_prefix(TUN_ROUTE_DEST, TUN_ROUTE_PREFIX)
         .output_interface(link_index)
         .execute()
         .await?;
@@ -83,10 +81,21 @@ pub async fn setup_node(addr: Ipv6Addr) -> Result<Arc<Tun>, Box<dyn std::error::
         }
     };
 
+
     let (conn, handle, _) = rtnetlink::new_connection()?;
     tokio::spawn(conn);
 
-    match add_address(handle.clone(), addr).await {
+    let tun_link_index = match retrieve_tun_link_index(handle.clone()).await {
+        Ok(link_index) => {
+            println!("TUN interface link index retrieved");
+            link_index
+        }
+        Err(e) => {
+            panic!("Error retrieving TUN interface link index: {}", e);
+        }
+    };
+
+    match add_address(handle.clone(), addr, tun_link_index).await {
         Ok(_) => {
             println!("Address added to TUN interface");
         }
@@ -95,7 +104,8 @@ pub async fn setup_node(addr: Ipv6Addr) -> Result<Arc<Tun>, Box<dyn std::error::
         }
     };
 
-    match add_route(handle.clone()).await {
+    // add route for /7 (global scope for the overlay)
+    match add_route(handle.clone(), tun_link_index).await {
         Ok(_) => {
             println!("Route added to TUN interface");
         }
diff --git a/src/x25519.rs b/src/x25519.rs
index d9d1dd3..3c66c30 100644
--- a/src/x25519.rs
+++ b/src/x25519.rs
@@ -53,7 +53,7 @@ pub fn generate_addr_from_pubkey(pubkey: &PublicKey) -> Ipv6Addr {
     hasher.finalize_variable(&mut buf).unwrap();
 
     let ipv6_bytes: [u8; 16] = [
-        0x20, 0x00, // This prefix ensures the address falls into the 200::/7 range
+        0x02, 0x00, // This prefix ensures the address falls into the 200::/7 range
         buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7], buf[8], buf[9], buf[10],
         buf[11], buf[12], buf[13],
     ];