Change routes on Android when allow lan is enabled

1 files changed, 47 insertions, 1 deletions

diff --git a/talpid-core/src/tunnel/tun_provider/android/mod.rs b/talpid-core/src/tunnel/tun_provider/android/mod.rs
index 85108ecb32..6de6217a31 100644
--- a/talpid-core/src/tunnel/tun_provider/android/mod.rs
+++ b/talpid-core/src/tunnel/tun_provider/android/mod.rs
@@ -1,5 +1,6 @@
 mod ipnetwork_sub;
 
+use self::ipnetwork_sub::IpNetworkSub;
 use super::TunConfig;
 use ipnetwork::IpNetwork;
 use jnix::{
@@ -263,7 +264,52 @@ impl AndroidTunProvider {
             .as_raw_fd())
     }
 
+    fn prepare_tun_config(&self, config: TunConfig) -> TunConfig {
+        if self.allow_lan {
+            let (required_ipv4_routes, required_ipv6_routes) = config
+                .required_routes
+                .iter()
+                .cloned()
+                .partition::<Vec<_>, _>(|route| route.is_ipv4());
+
+            let (original_lan_ipv4_networks, original_lan_ipv6_networks) =
+                crate::firewall::ALLOWED_LAN_NETS
+                    .iter()
+                    .chain(crate::firewall::ALLOWED_LAN_MULTICAST_NETS.iter())
+                    .cloned()
+                    .partition::<Vec<_>, _>(|network| network.is_ipv4());
+
+            let lan_ipv4_networks = original_lan_ipv4_networks
+                .into_iter()
+                .flat_map(|network| network.sub_all(required_ipv4_routes.iter().cloned()))
+                .collect::<Vec<_>>();
+
+            let lan_ipv6_networks = original_lan_ipv6_networks
+                .into_iter()
+                .flat_map(|network| network.sub_all(required_ipv6_routes.iter().cloned()))
+                .collect::<Vec<_>>();
+
+            let routes = config
+                .routes
+                .iter()
+                .flat_map(|&route| {
+                    if route.is_ipv4() {
+                        route.sub_all(lan_ipv4_networks.iter().cloned())
+                    } else {
+                        route.sub_all(lan_ipv6_networks.iter().cloned())
+                    }
+                })
+                .collect();
+
+            TunConfig { routes, ..config }
+        } else {
+            config
+        }
+    }
+
     fn open_tun(&mut self, config: TunConfig) -> Result<(), Error> {
+        let actual_config = self.prepare_tun_config(config.clone());
+
         let env = JnixEnv::from(
             self.jvm
                 .attach_current_thread_as_daemon()
@@ -277,7 +323,7 @@ impl AndroidTunProvider {
             )
             .map_err(|cause| Error::FindMethod("createTun", cause))?;
 
-        let java_config = config.clone().into_java(&env);
+        let java_config = actual_config.clone().into_java(&env);
         let result = env
             .call_method_unchecked(
                 self.object.as_obj(),