Check for resolv.conf symlink to systemd-resolved

3 files changed, 27 insertions, 4 deletions

diff --git a/talpid-core/src/security/linux/dns/mod.rs b/talpid-core/src/security/linux/dns/mod.rs
index c1e36efa53..0ab82c5d15 100644
--- a/talpid-core/src/security/linux/dns/mod.rs
+++ b/talpid-core/src/security/linux/dns/mod.rs
@@ -1,3 +1,5 @@
+extern crate resolv_conf;
+
 mod network_manager;
 mod resolvconf;
 mod static_resolv_conf;
@@ -10,6 +12,8 @@ use self::resolvconf::Resolvconf;
 use self::static_resolv_conf::StaticResolvConf;
 use self::systemd_resolved::SystemdResolved;
 
+const RESOLV_CONF_PATH: &str = "/etc/resolv.conf";
+
 error_chain! {
     errors {
         NoDnsSettingsManager {
diff --git a/talpid-core/src/security/linux/dns/static_resolv_conf.rs b/talpid-core/src/security/linux/dns/static_resolv_conf.rs
index e9e81e5446..6ece9ba44c 100644
--- a/talpid-core/src/security/linux/dns/static_resolv_conf.rs
+++ b/talpid-core/src/security/linux/dns/static_resolv_conf.rs
@@ -1,5 +1,4 @@
 extern crate notify;
-extern crate resolv_conf;
 
 use std::net::IpAddr;
 use std::ops::DerefMut;
@@ -9,9 +8,9 @@ use std::{fs, io, thread};
 use error_chain::ChainedError;
 
 use self::notify::{RecommendedWatcher, RecursiveMode, Watcher};
-use self::resolv_conf::{Config, ScopedIp};
+use super::resolv_conf::{Config, ScopedIp};
+use super::RESOLV_CONF_PATH;
 
-const RESOLV_CONF_PATH: &str = "/etc/resolv.conf";
 const RESOLV_CONF_BACKUP_PATH: &str = "/etc/resolv.conf.mullvadbackup";
 
 error_chain! {
diff --git a/talpid-core/src/security/linux/dns/systemd_resolved.rs b/talpid-core/src/security/linux/dns/systemd_resolved.rs
index 5c416187fd..72743d8913 100644
--- a/talpid-core/src/security/linux/dns/systemd_resolved.rs
+++ b/talpid-core/src/security/linux/dns/systemd_resolved.rs
@@ -1,6 +1,8 @@
 extern crate dbus;
 
-use std::net::IpAddr;
+use std::fs;
+use std::net::{IpAddr, Ipv4Addr};
+use std::path::Path;
 
 use error_chain::ChainedError;
 use libc::{AF_INET, AF_INET6};
@@ -10,6 +12,7 @@ use self::dbus::stdintf::*;
 use self::dbus::{BusType, Interface, Member, MessageItem, MessageItemArray, Signature};
 
 use super::super::iface_index;
+use super::{resolv_conf, RESOLV_CONF_PATH};
 
 error_chain! {
     errors {
@@ -38,6 +41,7 @@ error_chain! {
 
 }
 
+const DYNAMIC_RESOLV_CONF_PATH: &str = "/run/systemd/resolve/resolv.conf";
 const RESOLVED_BUS: &str = "org.freedesktop.resolve1";
 const RPC_TIMEOUT_MS: i32 = 1000;
 
@@ -65,6 +69,7 @@ impl SystemdResolved {
             interface_link: None,
         };
 
+        SystemdResolved::ensure_resolved_is_active()?;
         systemd_resolved.ensure_resolved_exists()?;
 
         Ok(systemd_resolved)
@@ -79,6 +84,21 @@ impl SystemdResolved {
         Ok(())
     }
 
+    fn ensure_resolved_is_active() -> Result<()> {
+        ensure!(
+            Self::resolv_conf_is_resolved_symlink(),
+            ErrorKind::NoSystemdResolved
+        );
+
+        Ok(())
+    }
+
+    fn resolv_conf_is_resolved_symlink() -> bool {
+        fs::read_link(RESOLV_CONF_PATH)
+            .map(|resolv_conf_target| resolv_conf_target == Path::new(DYNAMIC_RESOLV_CONF_PATH))
+            .unwrap_or_else(|_| false)
+    }
+
     fn as_manager_object<'a>(&'a self) -> dbus::ConnPath<'a, &'a dbus::Connection> {
         self.dbus_connection
             .with_path(RESOLVED_BUS, "/org/freedesktop/resolve1", RPC_TIMEOUT_MS)