From: Daniel Lenski <dlenski@gmail.com>
Date: Tue, 30 Nov 2021 18:06:44 +0000 (-0800)
Subject: Always use INTERNAL_IP4_ADDRESS as "gateway" on Windows
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a850bc40d454041ed58f461cf35d7065013b1f90;p=users%2Fdwmw2%2Fvpnc-scripts.git

Always use INTERNAL_IP4_ADDRESS as "gateway" on Windows

It appears that Windows's 'netsh' utility doesn't like the VPN interface
having a "gateway" address of 0.0.0.1, which is what vpnc-script-win.js
would attempt to use if INTERNAL_IP4_NETMASK is /0.  See
https://gitlab.com/openconnect/openconnect/-/merge_requests/306#note_745139972.

As noted in the OpenConnect source, "It's a tunnel; having a gateway is
meaningless."

Setting the "gateway" address for Windows to match INTERNAL_IP4_ADDRESS
seems like the simplest way to make 'netsh' configure routingly correctly in
all cases, including when the INTERNAL_IP4_NETMASK is either /0 or /32.

Signed-off-by: Daniel Lenski <dlenski@gmail.com>
---

diff --git a/vpnc-script-win.js b/vpnc-script-win.js
index 63235c8..5e76f8e 100644
--- a/vpnc-script-win.js
+++ b/vpnc-script-win.js
@@ -66,18 +66,14 @@ case "pre-init":
     break;
 case "connect":
     var gw = getDefaultGateway();
-    // Calculate the first legal host address in subnet
-    // (identical to the INTERNAL_IP4_ADDRESS if the netmask is
-    // 255.255.255.255, otherwise increment the last octet)
-    // We also need to work around the fact that
-    // INTERNAL_IP4_{NETMASK,NETADDR} are not always set for
-    // all protocols.
+    // Use INTERNAL_IP4_ADDRESS as the "gateway" address for the
+    // VPN tunnel connection. As noted in the OpenConnect source,
+    // "It's a tunnel; having a gateway is meaningless." Setting
+    // the gateway to match the INTERNAL_IP4_ADDRESS seems like
+    // the simplest way to behave correctly in all cases,
+    // including when the INTERNAL_IP4_NETMASK is /0 or /32.
     var internal_ip4_netmask = env("INTERNAL_IP4_NETMASK") || "255.255.255.255";
-    var internal_ip4_netaddr = env("INTERNAL_IP4_NETADDR") || env("INTERNAL_IP4_ADDRESS");
-    var internal_gw_array = internal_ip4_netaddr.split(".");
-    if (internal_ip4_netmask.trim() != "255.255.255.255" && env("INTERNAL_IP4_NETMASKLEN") != 32)
-        internal_gw_array[3]++;
-    var internal_gw = internal_gw_array.join(".");
+    var internal_gw = env("INTERNAL_IP4_ADDRESS");
 
     echo("VPN Gateway: " + env("VPNGATEWAY"));
     echo("Internal Address: " + env("INTERNAL_IP4_ADDRESS"));