ui,tunnel: add HTTP proxy setting to Go backend

Only make the HTTP proxy settings visible on supported Android versions,
i.e. Android 10 (AKA Android Q) and later.

Signed-off-by: Mikael Magnusson <mikma@users.sourceforge.net>

4 files changed, 125 insertions, 1 deletions

diff --git a/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
index 429cb1f1..242f81d8 100644
--- a/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
+++ b/tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java
@@ -7,6 +7,7 @@ package com.wireguard.android.backend;
 
 import android.content.Context;
 import android.content.Intent;
+import android.net.ProxyInfo;
 import android.os.Build;
 import android.os.ParcelFileDescriptor;
 import android.system.OsConstants;
@@ -24,6 +25,7 @@ import com.wireguard.crypto.KeyFormatException;
 import com.wireguard.util.NonNullForAll;
 
 import java.net.InetAddress;
+import java.net.URL;
 import java.time.Instant;
 import java.util.Collections;
 import java.util.Set;
@@ -318,6 +320,10 @@ public final class GoBackend implements Backend {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
                 service.setUnderlyingNetworks(null);
 
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                config.getInterface().getHttpProxy().ifPresent(pi -> builder.setHttpProxy(pi.getProxyInfo()));
+            }
+
             builder.setBlocking(true);
             try (final ParcelFileDescriptor tun = builder.establish()) {
                 if (tun == null)
diff --git a/tunnel/src/main/java/com/wireguard/config/BadConfigException.java b/tunnel/src/main/java/com/wireguard/config/BadConfigException.java
index db022e14..0d41cc05 100644
--- a/tunnel/src/main/java/com/wireguard/config/BadConfigException.java
+++ b/tunnel/src/main/java/com/wireguard/config/BadConfigException.java
@@ -8,6 +8,8 @@ package com.wireguard.config;
 import com.wireguard.crypto.KeyFormatException;
 import com.wireguard.util.NonNullForAll;
 
+import java.net.MalformedURLException;
+
 import androidx.annotation.Nullable;
 
 @NonNullForAll
@@ -44,6 +46,12 @@ public class BadConfigException extends Exception {
     }
 
     public BadConfigException(final Section section, final Location location,
+                              @Nullable final CharSequence text,
+                              final MalformedURLException cause) {
+        this(section, location, Reason.INVALID_VALUE, text, cause);
+    }
+
+    public BadConfigException(final Section section, final Location location,
                               final ParseException cause) {
         this(section, location, Reason.INVALID_VALUE, cause.getText(), cause);
     }
@@ -73,6 +81,7 @@ public class BadConfigException extends Exception {
         ENDPOINT("Endpoint"),
         EXCLUDED_APPLICATIONS("ExcludedApplications"),
         INCLUDED_APPLICATIONS("IncludedApplications"),
+        HTTP_PROXY("HttpProxy"),
         LISTEN_PORT("ListenPort"),
         MTU("MTU"),
         PERSISTENT_KEEPALIVE("PersistentKeepalive"),
diff --git a/tunnel/src/main/java/com/wireguard/config/HttpProxy.java b/tunnel/src/main/java/com/wireguard/config/HttpProxy.java
new file mode 100644
index 00000000..0a9d19f6
--- /dev/null
+++ b/tunnel/src/main/java/com/wireguard/config/HttpProxy.java
@@ -0,0 +1,78 @@
+/*
+ * Copyright © 2023 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.config;
+
+import com.wireguard.config.BadConfigException.Location;
+import com.wireguard.config.BadConfigException.Section;
+import com.wireguard.util.NonNullForAll;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import android.net.ProxyInfo;
+import android.net.Uri;
+
+@NonNullForAll
+public final class HttpProxy {
+    public static final int DEFAULT_PROXY_PORT = 8080;
+
+    private ProxyInfo pi;
+
+    protected HttpProxy(ProxyInfo pi) {
+        this.pi = pi;
+    }
+
+    public ProxyInfo getProxyInfo() {
+        return pi;
+    }
+
+    public String getHost() {
+        return pi.getHost();
+    }
+
+    public Uri getPacFileUrl() {
+        return pi.getPacFileUrl();
+    }
+
+    public int getPort() {
+        return pi.getPort();
+    }
+
+    public static HttpProxy parse(final String httpProxy) throws BadConfigException {
+        try {
+            if (httpProxy.startsWith("pac:")) {
+                return new HttpProxy(ProxyInfo.buildPacProxy(Uri.parse(httpProxy.substring(4))));
+            } else {
+                final String urlStr;
+                if (!httpProxy.contains("://")) {
+                    urlStr = "http://" + httpProxy;
+                } else {
+                    urlStr = httpProxy;
+                }
+                URL url = new URL(urlStr);
+                return new HttpProxy(ProxyInfo.buildDirectProxy(url.getHost(), url.getPort() <= 0 ? DEFAULT_PROXY_PORT : url.getPort()));
+            }
+        } catch (final MalformedURLException e) {
+            throw new BadConfigException(Section.INTERFACE, Location.HTTP_PROXY, httpProxy, e);
+        }
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder sb = new StringBuilder();
+        if (pi.getPacFileUrl() != null && pi.getPacFileUrl() != Uri.EMPTY)
+            sb.append("pac:").append(pi.getPacFileUrl());
+        else {
+            sb.append("http://").append(pi.getHost()).append(':');
+            if (pi.getPort() <= 0)
+                sb.append(DEFAULT_PROXY_PORT);
+            else
+                sb.append(pi.getPort());
+        }
+
+        return sb.toString();
+    }
+}
diff --git a/tunnel/src/main/java/com/wireguard/config/Interface.java b/tunnel/src/main/java/com/wireguard/config/Interface.java
index bebca2e5..e47e0be3 100644
--- a/tunnel/src/main/java/com/wireguard/config/Interface.java
+++ b/tunnel/src/main/java/com/wireguard/config/Interface.java
@@ -46,6 +46,7 @@ public final class Interface {
     private final KeyPair keyPair;
     private final Optional<Integer> listenPort;
     private final Optional<Integer> mtu;
+    private final Optional<HttpProxy> httpProxy;
 
     private Interface(final Builder builder) {
         // Defensively copy to ensure immutability even if the Builder is reused.
@@ -57,6 +58,7 @@ public final class Interface {
         keyPair = Objects.requireNonNull(builder.keyPair, "Interfaces must have a private key");
         listenPort = builder.listenPort;
         mtu = builder.mtu;
+        httpProxy = builder.httpProxy;
     }
 
     /**
@@ -92,6 +94,9 @@ public final class Interface {
                 case "mtu":
                     builder.parseMtu(attribute.getValue());
                     break;
+                case "httpproxy":
+                    builder.parseHttpProxy(attribute.getValue());
+                    break;
                 case "privatekey":
                     builder.parsePrivateKey(attribute.getValue());
                     break;
@@ -115,7 +120,8 @@ public final class Interface {
                 && includedApplications.equals(other.includedApplications)
                 && keyPair.equals(other.keyPair)
                 && listenPort.equals(other.listenPort)
-                && mtu.equals(other.mtu);
+                && mtu.equals(other.mtu)
+                && httpProxy.equals(other.httpProxy);
     }
 
     /**
@@ -195,6 +201,15 @@ public final class Interface {
         return mtu;
     }
 
+    /**
+     * Returns the HTTP proxy used for the WireGuard interface.
+     *
+     * @return the HTTP proxy, or {@code Optional.empty()} if none is configured
+     */
+    public Optional<HttpProxy> getHttpProxy() {
+        return httpProxy;
+    }
+
     @Override
     public int hashCode() {
         int hash = 1;
@@ -205,6 +220,7 @@ public final class Interface {
         hash = 31 * hash + keyPair.hashCode();
         hash = 31 * hash + listenPort.hashCode();
         hash = 31 * hash + mtu.hashCode();
+        hash = 31 * hash + httpProxy.hashCode();
         return hash;
     }
 
@@ -244,6 +260,7 @@ public final class Interface {
             sb.append("IncludedApplications = ").append(Attribute.join(includedApplications)).append('\n');
         listenPort.ifPresent(lp -> sb.append("ListenPort = ").append(lp).append('\n'));
         mtu.ifPresent(m -> sb.append("MTU = ").append(m).append('\n'));
+        httpProxy.ifPresent(p -> sb.append("HttpProxy = ").append(p).append('\n'));
         sb.append("PrivateKey = ").append(keyPair.getPrivateKey().toBase64()).append('\n');
         return sb.toString();
     }
@@ -279,6 +296,8 @@ public final class Interface {
         private Optional<Integer> listenPort = Optional.empty();
         // Defaults to not present.
         private Optional<Integer> mtu = Optional.empty();
+        // Defaults to not present.
+        private Optional<HttpProxy> httpProxy = Optional.empty();
 
         public Builder addAddress(final InetNetwork address) {
             addresses.add(address);
@@ -391,6 +410,10 @@ public final class Interface {
             }
         }
 
+        public Builder parseHttpProxy(final String httpProxy) throws BadConfigException {
+            return setHttpProxy(HttpProxy.parse(httpProxy));
+        }
+
         public Builder parsePrivateKey(final String privateKey) throws BadConfigException {
             try {
                 return setKeyPair(new KeyPair(Key.fromBase64(privateKey)));
@@ -419,5 +442,13 @@ public final class Interface {
             this.mtu = mtu == 0 ? Optional.empty() : Optional.of(mtu);
             return this;
         }
+
+        public Builder setHttpProxy(final HttpProxy httpProxy) throws BadConfigException {
+            if (httpProxy == null)
+                throw new BadConfigException(Section.INTERFACE, Location.HTTP_PROXY,
+                        Reason.INVALID_VALUE, String.valueOf(httpProxy));
+            this.httpProxy = httpProxy == null ? Optional.empty() : Optional.of(httpProxy);
+            return this;
+        }
     }
 }