From 6b02a200285baebaf61704877a478df263eb13b1 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Mon, 28 Nov 2016 14:45:30 -0700
Subject: [PATCH] Fix loopback

---
 schemes/ipd/src/interface/ethernet.rs | 4 ++++
 schemes/ipd/src/interface/loopback.rs | 8 +++++---
 schemes/ipd/src/interface/mod.rs      | 1 +
 schemes/ipd/src/main.rs               | 2 +-
 4 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/schemes/ipd/src/interface/ethernet.rs b/schemes/ipd/src/interface/ethernet.rs
index 4c0bb78..d914a78 100644
--- a/schemes/ipd/src/interface/ethernet.rs
+++ b/schemes/ipd/src/interface/ethernet.rs
@@ -37,6 +37,10 @@ impl Interface for EthernetInterface {
         self.ip
     }
 
+    fn routable(&self, dst: Ipv4Addr) -> bool {
+        dst != Ipv4Addr::LOOPBACK
+    }
+
     fn arp_event(&mut self) -> Result<()> {
         loop {
             let mut bytes = [0; 65536];
diff --git a/schemes/ipd/src/interface/loopback.rs b/schemes/ipd/src/interface/loopback.rs
index 61c7e8c..a957ef8 100644
--- a/schemes/ipd/src/interface/loopback.rs
+++ b/schemes/ipd/src/interface/loopback.rs
@@ -4,14 +4,12 @@ use std::io::Result;
 use interface::Interface;
 
 pub struct LoopbackInterface {
-    ip: Ipv4Addr,
     packets: Vec<Ipv4>
 }
 
 impl LoopbackInterface {
     pub fn new() -> Self {
         LoopbackInterface {
-            ip: Ipv4Addr::LOOPBACK,
             packets: Vec::new()
         }
     }
@@ -19,7 +17,11 @@ impl LoopbackInterface {
 
 impl Interface for LoopbackInterface {
     fn ip(&self) -> Ipv4Addr {
-        self.ip
+        Ipv4Addr::LOOPBACK
+    }
+
+    fn routable(&self, dst: Ipv4Addr) -> bool {
+        dst == Ipv4Addr::LOOPBACK
     }
 
     fn recv(&mut self) -> Result<Vec<Ipv4>> {
diff --git a/schemes/ipd/src/interface/mod.rs b/schemes/ipd/src/interface/mod.rs
index 279e2be..2fa89d9 100644
--- a/schemes/ipd/src/interface/mod.rs
+++ b/schemes/ipd/src/interface/mod.rs
@@ -9,6 +9,7 @@ mod loopback;
 
 pub trait Interface {
     fn ip(&self) -> Ipv4Addr;
+    fn routable(&self, dst: Ipv4Addr) -> bool;
     fn recv(&mut self) -> Result<Vec<Ipv4>>;
     fn send(&mut self, ip: Ipv4) -> Result<usize>;
 
diff --git a/schemes/ipd/src/main.rs b/schemes/ipd/src/main.rs
index 7c4fcaf..52ae0cb 100644
--- a/schemes/ipd/src/main.rs
+++ b/schemes/ipd/src/main.rs
@@ -194,7 +194,7 @@ impl SchemeMut for Ipd {
         if let Some(mut ip) = Ipv4::from_bytes(buf) {
             for mut interface in self.interfaces.iter_mut() {
                 let if_ip = interface.ip();
-                if ip.header.src == if_ip || ip.header.src == Ipv4Addr::NULL {
+                if ip.header.src == if_ip || (ip.header.src == Ipv4Addr::NULL && interface.routable(ip.header.dst)) {
                     ip.header.src = if_ip;
                     ip.header.proto = handle.proto;