Reduce open_tun calls (Establish)

Each call to Establish opens a window for leaks on android. By only
invoking Establish if the VpnConfig if any of the input has changed and
reusing it otherwise we avoid many of these leaks. This commit also
waits for android to report back that the routes have been created to
ping and verify connectivity to avoid pings going outside the tunnel.

1 files changed, 4 insertions, 0 deletions

diff --git a/talpid-core/src/tunnel_state_machine/connecting_state.rs b/talpid-core/src/tunnel_state_machine/connecting_state.rs
index 4faef9860f..cb06540b0f 100644
--- a/talpid-core/src/tunnel_state_machine/connecting_state.rs
+++ b/talpid-core/src/tunnel_state_machine/connecting_state.rs
@@ -114,6 +114,10 @@ impl ConnectingState {
                         ErrorStateCause::SetFirewallPolicyError(error),
                     )
                 } else {
+                    // HACK: On Android, DNS is part of creating the VPN interface, this call
+                    // ensures that the vpn_config is prepared with correct DNS servers in case they
+                    // previously set to something else, e.g. in the case of blocking. This call
+                    // should probably be part of start_tunnel call.
                     #[cfg(target_os = "android")]
                     {
                         shared_values.prepare_tun_config(false);