Exclude ourselves from the VPN, to avoid pings becoming recursive

Our ping proxy uses isReachable, which doesn't give us an explicit socket, so can't
be protected and kept out of the VPN. Without this (or filtering to just the ping
app, as I had been testing before...) pings result in a ping back into our own VPN,
and the whole app crashes in short order.

Author: pimterry

app/src/main/java/tech/httptoolkit/android/ProxyVpnService.kt

@@ -149,10 +149,18 @@ class ProxyVpnService : VpnService(), IProtectSocket {
                 .addAddress(VPN_IP_ADDRESS, 32)
                 .addRoute(ALL_ROUTES, 0)
                 .apply {
+                    // We exclude ourselves from interception, so we can still make network requests
+                    // separately, primarily because otherwise pinging with isReachable is recursive.
+                    val httpToolkitPackage = packageName
+
                     // For some reason, with Genymotion the whole device crashes if we intercept
                     // blindly, but intercepting every single application explicitly is fine.
                     if (isGenymotion) {
-                        packageNames.forEach { name -> addAllowedApplication(name) }
+                        packageNames.forEach { name ->
+                            if (name != httpToolkitPackage) addAllowedApplication(name)
+                        }
+                    } else {
+                        addDisallowedApplication(httpToolkitPackage)
                     }
                 }
                 .setSession(getString(R.string.app_name))