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authorcyBerta <cyberta@riseup.net>2022-12-30 03:18:51 +0100
committercyBerta <cyberta@riseup.net>2023-04-18 00:52:47 +0200
commitd86284fd86603e869221a621e1f2953d5a0302d2 (patch)
tree92d875e62859bcb3a1c48b6f7d2becc2766d1595 /app/src/main/java
parentd628a7e808c68682ed6fac33970659781129f511 (diff)
always try the complementary DNS resolution strategy if the primary one failed
Diffstat (limited to 'app/src/main/java')
-rw-r--r--app/src/main/java/se/leap/bitmaskclient/providersetup/connectivity/DnsResolver.java127
1 files changed, 67 insertions, 60 deletions
diff --git a/app/src/main/java/se/leap/bitmaskclient/providersetup/connectivity/DnsResolver.java b/app/src/main/java/se/leap/bitmaskclient/providersetup/connectivity/DnsResolver.java
index b50c480d..c6cc5305 100644
--- a/app/src/main/java/se/leap/bitmaskclient/providersetup/connectivity/DnsResolver.java
+++ b/app/src/main/java/se/leap/bitmaskclient/providersetup/connectivity/DnsResolver.java
@@ -1,84 +1,85 @@
- package se.leap.bitmaskclient.providersetup.connectivity;
+package se.leap.bitmaskclient.providersetup.connectivity;
- import static java.net.InetAddress.getByName;
+import static java.net.InetAddress.getByName;
- import android.util.Log;
+import android.util.Log;
- import androidx.annotation.NonNull;
+import androidx.annotation.NonNull;
- import java.net.InetAddress;
- import java.net.UnknownHostException;
- import java.util.ArrayList;
- import java.util.List;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.List;
- import de.blinkt.openvpn.core.VpnStatus;
- import okhttp3.Dns;
- import okhttp3.HttpUrl;
- import okhttp3.OkHttpClient;
- import okhttp3.dnsoverhttps.DnsOverHttps;
- import se.leap.bitmaskclient.base.models.Provider;
- import se.leap.bitmaskclient.base.models.ProviderObservable;
- import se.leap.bitmaskclient.base.utils.IPAddress;
+import de.blinkt.openvpn.core.VpnStatus;
+import okhttp3.Dns;
+import okhttp3.HttpUrl;
+import okhttp3.OkHttpClient;
+import okhttp3.dnsoverhttps.DnsOverHttps;
+import se.leap.bitmaskclient.base.models.Provider;
+import se.leap.bitmaskclient.base.models.ProviderObservable;
+import se.leap.bitmaskclient.base.utils.IPAddress;
class DnsResolver implements Dns {
OkHttpClient dohHttpClient;
- boolean forceDoH;
+ boolean preferDoH;
- public DnsResolver(OkHttpClient dohHttpClient, boolean forceDoH) {
+ public DnsResolver(OkHttpClient dohHttpClient, boolean preferDoH) {
this.dohHttpClient = dohHttpClient;
- this.forceDoH = forceDoH;
+ this.preferDoH = preferDoH;
}
@NonNull
@Override
public List<InetAddress> lookup(@NonNull String hostname) throws UnknownHostException {
Log.d("DNS", "trying to resolve DNS for " + hostname);
+ List<InetAddress> list = null;
+ if (preferDoH) {
+ if ((list = tryLookupDoH(hostname)) == null) {
+ list = tryLookupSystemDNS(hostname);
+ }
+ } else {
+ if ((list = tryLookupSystemDNS(hostname)) == null) {
+ list = tryLookupDoH(hostname);
+ }
+ }
+
+ if (list != null) {
+ return list;
+ }
+ Log.d("DNS", "try hard coded IPs");
+ // let's check if there's an hard-coded IP we can use
+ ProviderObservable observable = ProviderObservable.getInstance();
+ Provider currentProvider;
+ if (observable.getProviderForDns() != null) {
+ currentProvider = observable.getProviderForDns();
+ } else {
+ currentProvider = observable.getCurrentProvider();
+ }
+ String ip = currentProvider.getIpForHostname(hostname);
+ if (!ip.isEmpty()) {
+ VpnStatus.logWarning("[API] Normal DNS resolution for " + hostname + " seems to be blocked. Circumventing.");
+ ArrayList<InetAddress> addresses = new ArrayList<>();
+ addresses.add(InetAddress.getByAddress(hostname, IPAddress.asBytes(ip)));
+ return addresses;
+ } else {
+ VpnStatus.logWarning("[API] Could not resolve DNS for " + hostname);
+ throw new UnknownHostException("Hostname " + hostname + " not found");
+ }
+ }
+
+ private List<InetAddress> tryLookupSystemDNS(@NonNull String hostname) throws RuntimeException, UnknownHostException {
try {
- if (forceDoH) {
- List<InetAddress> list = lookupDoH(hostname);
- for (InetAddress address : list) {
- Log.d("DNS", "DoH ---> " + address.toString());
- }
- return list;
- }
+ Log.d("DNS", "trying to resolve " + hostname + "with system DNS");
return Dns.SYSTEM.lookup(hostname);
} catch (UnknownHostException e) {
e.printStackTrace();
- Log.e("DNS", "DoH via cloudflare failed");
-
- // if not yet tried, do DNS over Https after normal DNS failed
- if (!forceDoH) {
- try {
- return lookupDoH(hostname);
- } catch (RuntimeException uhe) {
- uhe.printStackTrace();
- }
- }
-
- Log.d("DNS", "try hard coded IPs");
- // let's check if there's an hard-coded IP we can use
- ProviderObservable observable = ProviderObservable.getInstance();
- Provider currentProvider;
- if (observable.getProviderForDns() != null) {
- currentProvider = observable.getProviderForDns();
- } else {
- currentProvider = observable.getCurrentProvider();
- }
- String ip = currentProvider.getIpForHostname(hostname);
- if (!ip.isEmpty()) {
- VpnStatus.logWarning("[API] Normal DNS resolution for " + hostname + " seems to be blocked. Circumventing.");
- ArrayList<InetAddress> addresses = new ArrayList<>();
- addresses.add(InetAddress.getByAddress(hostname, IPAddress.asBytes(ip)));
- return addresses;
- } else {
- VpnStatus.logWarning("[API] Could not resolve DNS for " + hostname);
- throw new UnknownHostException("Hostname " + hostname + " not found");
- }
+ return null;
}
}
- private List<InetAddress> lookupDoH(@NonNull String hostname) throws RuntimeException, UnknownHostException {
+ private List<InetAddress> tryLookupDoH(@NonNull String hostname) throws UnknownHostException {
DnsOverHttps ahablitzDoHClient = new DnsOverHttps.Builder().client(dohHttpClient)
.url(HttpUrl.get("https://blitz.ahadns.com"))
.build();
@@ -86,7 +87,7 @@ class DnsResolver implements Dns {
Log.d("DNS", "DoH via blitz.ahadns.com");
return ahablitzDoHClient.lookup(hostname);
} catch (UnknownHostException e) {
- e.printStackTrace();
+ e.printStackTrace();
Log.e("DNS", "DoH via blitz.ahadns.com failed");
}
@@ -108,7 +109,13 @@ class DnsResolver implements Dns {
.bootstrapDnsHosts(getByName("1.1.1.1"), getByName("1.0.0.1"))
.build();
- Log.d("DNS", "DoH via cloudflare 1.1.1.1");
- return cloudFlareDoHClient.lookup(hostname);
+ try {
+ Log.d("DNS", "DoH via cloudflare 1.1.1.1");
+ return cloudFlareDoHClient.lookup(hostname);
+ } catch (UnknownHostException e) {
+ e.printStackTrace();
+ Log.e("DNS", "DoH via cloudflare failed");
+ }
+ return null;
}
}