Finally I decided to add High Performance SSH.

http://www.psc.edu/networking/projects/hpn-ssh/

I tried to keep the openssh hash not changing, unless the user sets hpn in getConfig
style. I think that does not look as good as a patch changing the hash, but it may
annoy less. Let me know if it is not ok.

I don't think hpn should be the default, because it may have some insecurity implications
I don't know of. But I used to enable it in all my machines, and I hope to do so unless
advised otherwise.

svn path=/nixpkgs/trunk/; revision=18073

pkgs/tools/networking/openssh/default.nix

@@ -1,11 +1,12 @@
 { stdenv, fetchurl, zlib, openssl, perl
 , pamSupport ? false, pam ? null
 , etcDir ? null
+, hpnSupport ? false
 }:
 
 assert pamSupport -> pam != null;
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (rec {
   name = "openssh-5.2p1";
 
   src = fetchurl {
@@ -36,4 +37,16 @@ stdenv.mkDerivation rec {
   ";
 
   installTargets = "install-nosysconf";
+} //
+(if hpnSupport then
+rec {
+   hpnSrc = fetchurl {
+     url = http://www.psc.edu/networking/projects/hpn-ssh/openssh-5.2p1-hpn13v6.diff.gz;
+     sha256 = "1g91xl1vfg772072qcbcfzyqj7yfvm38xgk8zyy8wsl2g81rb8wh";
+   };
+
+   patchPhase = ''
+     gunzip -c ${hpnSrc} | patch -p1
+   '';
 }
+else {}))

pkgs/top-level/all-packages.nix

@@ -1224,6 +1224,7 @@ let
   openssh = import ../tools/networking/openssh {
     inherit fetchurl stdenv zlib openssl pam perl;
     pamSupport = getPkgConfig "openssh" "pam" true;
+    hpnSupport = getConfig [ "openssh" "hpn" ] false;
     etcDir = getConfig [ "openssh" "etcDir" ] "/etc/ssh";
   };