Allow setting the DNS module through env. variable

2 files changed, 17 insertions, 0 deletions

diff --git a/README.md b/README.md
index e3d1d3c642..9b4065a2d6 100644
--- a/README.md
+++ b/README.md
@@ -140,6 +140,12 @@ sections.
 * `TALPID_NFTABLES_COUNTERS` - Set to `"1"` to add packet counters to all firewall rules on
   Linux.
 
+* `TALPID_DNS_MODULE` - Allows changing the method that will be used for DNS configuration on Linux.
+  By default this is automatically detected, but you can set it to one of the options below to
+  choose a specific method:
+    * `"static-file"`: change the `/etc/resolv.conf` file directly
+    * `"resolvconf"`: use the `resolvconf` program
+
 
 ## Building and running the Electron GUI app
 
diff --git a/talpid-core/src/security/linux/dns/mod.rs b/talpid-core/src/security/linux/dns/mod.rs
index 3e6dafed0f..7cc004ce96 100644
--- a/talpid-core/src/security/linux/dns/mod.rs
+++ b/talpid-core/src/security/linux/dns/mod.rs
@@ -1,6 +1,7 @@
 mod resolvconf;
 mod static_resolv_conf;
 
+use std::env;
 use std::net::IpAddr;
 
 use self::resolvconf::Resolvconf;
@@ -26,6 +27,16 @@ pub enum DnsSettings {
 
 impl DnsSettings {
     pub fn new() -> Result<Self> {
+        let dns_module = env::var_os("TALPID_DNS_MODULE");
+
+        Ok(match dns_module.as_ref().and_then(|value| value.to_str()) {
+            Some("static-file") => DnsSettings::StaticResolvConf(StaticResolvConf::new()?),
+            Some("resolvconf") => DnsSettings::Resolvconf(Resolvconf::new()?),
+            Some(_) | None => Self::with_detected_dns_manager()?,
+        })
+    }
+
+    fn with_detected_dns_manager() -> Result<Self> {
         Resolvconf::new()
             .map(DnsSettings::Resolvconf)
             .or_else(|_| StaticResolvConf::new().map(DnsSettings::StaticResolvConf))