fix: Destination ports used in network traffic

.gitignore

@@ -5,3 +5,4 @@ core
 **/core
 .direnv
 result
+sparse-public

sparse-05/sparse-05-client/src/commands/connect/mod.rs

@@ -110,8 +110,8 @@ pub async fn connect(config: PathBuf, ip: SocketAddr) -> anyhow::Result<()> {
             Ok(packet) => {
                 let (count, addr) = packet?;
 
-                if addr != ip {
-                    bail!("received response from wrong source");
+                if addr.ip() != ip.ip() {
+                    bail!("received response from wrong source (expected {ip:?}; got {addr:?})");
                 }
 
                 let data = &buf[..count];

sparse-05/sparse-05-server/src/connection.rs

@@ -40,6 +40,7 @@ struct ConnectionInformation {
     srcip: Ipv4Addr,
     dstip: Ipv4Addr,
     srcport: u16,
+    listen_port: u16,
     packet_sender: Sender<EthernetPacket>,
 }
 
@@ -47,7 +48,7 @@ impl ConnectionInformation {
     fn format_udp_packet(&self, data: &[u8]) -> EthernetPacket {
         use packets::*;
 
-        let udp_packet = UDPPacket::construct(54248, self.srcport, data);
+        let udp_packet = UDPPacket::construct(self.listen_port, self.srcport, data);
         let ip_packet =
             IPv4Packet::construct(self.dstip, self.srcip, &Layer4Packet::UDP(udp_packet));
         EthernetPacket::construct(self.dstmac, self.srcmac, &Layer3Packet::IPv4(ip_packet))
@@ -147,6 +148,7 @@ pub fn spawn_connection_handler(
             srcip: ip_pkt.source_ip(),
             dstip: ip_pkt.dest_ip(),
             srcport: udp_pkt.srcport(),
+            listen_port: udp_pkt.dstport(),
             packet_sender,
         }
     };

sparse-05/sparse-05-server/src/main.rs

@@ -2,7 +2,7 @@ use std::{
     collections::HashMap,
     net::Ipv4Addr,
     sync::{mpsc::channel, Arc, Mutex},
-    thread, ffi::OsString,
+    thread,
 };
 
 use anyhow::{bail, Context};