From 3c7a6eb53cb9895225e705544b3289e3cd79bedd Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Thu, 20 May 2010 23:07:21 +0000
Subject: [PATCH] * Make the Bittorrent test more interesting by putting one
 client   behind a NAT router and verifying that another client can connect to
   it through the NAT (using a UPnP-IGD mapping created automatically   by
 miniupnpd).

svn path=/nixos/trunk/; revision=21932
---
 tests/bittorrent.nix | 60 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 54 insertions(+), 6 deletions(-)

diff --git a/tests/bittorrent.nix b/tests/bittorrent.nix
index 01640e899d77..26b7f106865f 100644
--- a/tests/bittorrent.nix
+++ b/tests/bittorrent.nix
@@ -1,9 +1,24 @@
+# This test runs a Bittorrent tracker on one machine, and verifies
+# that two client machines can download the torrent using
+# `transmission'.  The first client (behind a NAT router) downloads
+# from the initial seeder running on the tracker.  Then we kill the
+# initial seeder.  The second client downloads from the first client,
+# which only works if the first client successfully uses the UPnP-IGD
+# protocol to poke a hole in the NAT.
+
 { pkgs, ... }:
 
 let
 
   # Some random file to serve.
   file = pkgs.nixUnstable.src;
+
+  miniupnpdConf = pkgs.writeText "miniupnpd.conf"
+    ''
+      ext_ifname=eth1
+      listening_ip=192.168.2.3/24
+      allow 1024-65535 192.168.2.0/24 1024-65535
+    '';
   
 in
 
@@ -20,7 +35,20 @@ in
           services.httpd.documentRoot = "/tmp";
         };
 
-      client = 
+      router = 
+        { config, pkgs, ... }:
+        { environment.systemPackages = [ pkgs.iptables pkgs.miniupnpd ];
+          virtualisation.vlans = [ 1 2 ];
+        };
+
+      client1 = 
+        { config, pkgs, ... }:
+        { environment.systemPackages = [ pkgs.transmission ];
+          virtualisation.vlans = [ 2 ];
+          networking.defaultGateway = "192.168.2.3"; # !!! ugly
+        };
+
+      client2 = 
         { config, pkgs, ... }:
         { environment.systemPackages = [ pkgs.transmission ];
         };
@@ -30,6 +58,17 @@ in
     ''
       startAll;
 
+      # Enable NAT on the router and start miniupnpd.
+      $router->mustSucceed(
+          "iptables -t nat -F",
+          "iptables -t nat -A POSTROUTING -s 192.168.2.0/24 -d 192.168.2.0/24 -j ACCEPT",
+          "iptables -t nat -A POSTROUTING -s 192.168.2.0/24 -j SNAT --to-source 192.168.1.3", # !!! ugly
+          "iptables -t nat -N MINIUPNPD",
+          "iptables -t nat -A PREROUTING -i eth1 -j MINIUPNPD",
+          "echo 1 > /proc/sys/net/ipv4/ip_forward",
+          "miniupnpd -f ${miniupnpdConf}"
+      );
+
       # Create the torrent.
       $tracker->mustSucceed("mkdir /tmp/data");
       $tracker->mustSucceed("cp ${file} /tmp/data/test.tar.bz2");
@@ -41,13 +80,22 @@ in
       $tracker->waitForOpenPort(6969);
 
       # Start the initial seeder.
-      $tracker->mustSucceed("transmissioncli /tmp/test.torrent -M -w /tmp/data >&2 &");
+      my $pid = $tracker->mustSucceed("transmissioncli /tmp/test.torrent -M -w /tmp/data >&2 & echo \$!");
 
-      # Now we should be able to download from the client.
+      # Now we should be able to download from the client behind the NAT.
       $tracker->waitForJob("httpd");
-      $client->mustSucceed("transmissioncli http://tracker/test.torrent -M -w /tmp >&2 &");
-      $client->waitForFile("/tmp/test.tar.bz2");
-      $client->mustSucceed("cmp /tmp/test.tar.bz2 ${file}");
+      $client1->mustSucceed("transmissioncli http://tracker/test.torrent -w /tmp >&2 &");
+      $client1->waitForFile("/tmp/test.tar.bz2");
+      $client1->mustSucceed("cmp /tmp/test.tar.bz2 ${file}");
+
+      # Bring down the initial seeder.
+      $tracker->mustSucceed("kill -9 $pid");
+
+      # Now download from the second client.  This can only succeed if
+      # the first client created a NAT hole in the router.
+      $client2->mustSucceed("transmissioncli http://tracker/test.torrent -M -w /tmp >&2 &");
+      $client2->waitForFile("/tmp/test.tar.bz2");
+      $client2->mustSucceed("cmp /tmp/test.tar.bz2 ${file}");
     '';
   
 }