Update calling routing to return urls only, no instance IPs

service/src/main/java/org/whispersystems/textsecuregcm/calls/routing/DynamicConfigTurnRouter.java

@@ -62,6 +62,11 @@ public class DynamicConfigTurnRouter {
     return turnConfig.getRandomizeRate();
   }
 
+  public int getDefaultInstanceIpCount() {
+    final DynamicTurnConfiguration turnConfig = dynamicConfigurationManager.getConfiguration().getTurnConfiguration();
+    return turnConfig.getDefaultInstanceIpCount();
+  }
+
   public boolean shouldRandomize() {
     long rate = getRandomizeRate();
     return rate >= RANDOMIZE_RATE_BASIS || rng.nextLong(0, DynamicConfigTurnRouter.RANDOMIZE_RATE_BASIS) < rate;

service/src/main/java/org/whispersystems/textsecuregcm/calls/routing/TurnCallRouter.java

@@ -52,6 +52,13 @@ public class TurnCallRouter {
     this.stableSelect = stableSelect;
   }
 
+  public TurnServerOptions getRoutingFor(
+      @Nonnull final UUID aci,
+      @Nonnull final Optional<InetAddress> clientAddress
+  ) {
+    return getRoutingFor(aci, clientAddress,  this.configTurnRouter.getDefaultInstanceIpCount());
+  }
+
   /**
    * Gets Turn Instance addresses. Returns both the IPv4 and IPv6 addresses. Prefers to match the IP protocol of the
    * client address in datacenter selection. Returns 2 instance options of the preferred protocol for every one instance
@@ -79,10 +86,6 @@ public class TurnCallRouter {
       @Nonnull final Optional<InetAddress> clientAddress,
       final int instanceLimit
   ) {
-    if (instanceLimit < 1) {
-      throw new IllegalArgumentException("Limit cannot be less than one");
-    }
-
     String hostname = this.configTurnRouter.getHostname();
 
     List<String> targetedUrls = this.configTurnRouter.targetedUrls(aci);
@@ -90,7 +93,7 @@ public class TurnCallRouter {
       return new TurnServerOptions(hostname, null, targetedUrls);
     }
 
-    if(clientAddress.isEmpty() || this.configTurnRouter.shouldRandomize()) {
+    if(clientAddress.isEmpty() || this.configTurnRouter.shouldRandomize() || instanceLimit < 1) {
       return new TurnServerOptions(hostname, null, this.configTurnRouter.randomUrls());
     }
 

service/src/main/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicTurnConfiguration.java

@@ -23,6 +23,12 @@ public class DynamicTurnConfiguration {
   @JsonProperty
   private long randomizeRate = 5_000;
 
+  /**
+   * Number of instance ips to return in TURN routing request
+   */
+  @JsonProperty
+  private int defaultInstanceIpCount = 0;
+
   @JsonProperty
   private List<@Valid TurnUriConfiguration> uriConfigs = Collections.emptyList();
 
@@ -34,6 +40,10 @@ public class DynamicTurnConfiguration {
     return randomizeRate;
   }
 
+  public int getDefaultInstanceIpCount() {
+    return defaultInstanceIpCount;
+  }
+
   public String getHostname() {
     return hostname;
   }

service/src/main/java/org/whispersystems/textsecuregcm/controllers/CallRoutingControllerV2.java

@@ -18,7 +18,6 @@ import jakarta.ws.rs.Produces;
 import jakarta.ws.rs.container.ContainerRequestContext;
 import jakarta.ws.rs.core.Context;
 import jakarta.ws.rs.core.MediaType;
-import java.io.IOException;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
@@ -40,8 +39,8 @@ import org.whispersystems.websocket.auth.ReadOnly;
 @Path("/v2/calling")
 public class CallRoutingControllerV2 {
 
-  private static final int TURN_INSTANCE_LIMIT = 2;
   private static final Counter INVALID_IP_COUNTER = Metrics.counter(name(CallRoutingControllerV2.class, "invalidIP"));
+  private static final Counter CLOUDFLARE_TURN_ERROR_COUNTER = Metrics.counter(name(CallRoutingController.class, "cloudflareTurnError"));
   private final RateLimiters rateLimiters;
   private final TurnCallRouter turnCallRouter;
   private final TurnTokenGenerator tokenGenerator;
@@ -79,14 +78,19 @@ public class CallRoutingControllerV2 {
   public GetCallingRelaysResponse getCallingRelays(
       final @ReadOnly @Auth AuthenticatedDevice auth,
       @Context ContainerRequestContext requestContext
-  ) throws RateLimitExceededException, IOException {
+  ) throws RateLimitExceededException {
     UUID aci = auth.getAccount().getUuid();
     rateLimiters.getCallEndpointLimiter().validate(aci);
 
     List<TurnToken> tokens = new ArrayList<>();
+    try {
       if (experimentEnrollmentManager.isEnrolled(auth.getAccount().getNumber(), aci, "cloudflareTurn")) {
         tokens.add(cloudflareTurnCredentialsManager.retrieveFromCloudflare());
       }
+    } catch (Exception e) {
+      // emit counter, rely on Signal URL fallback
+      CallRoutingControllerV2.CLOUDFLARE_TURN_ERROR_COUNTER.increment();
+    }
 
     Optional<InetAddress> address = Optional.empty();
     try {
@@ -97,7 +101,7 @@ public class CallRoutingControllerV2 {
       INVALID_IP_COUNTER.increment();
     }
 
-    TurnServerOptions options = turnCallRouter.getRoutingFor(aci, address, TURN_INSTANCE_LIMIT);
+    TurnServerOptions options = turnCallRouter.getRoutingFor(aci, address);
     tokens.add(tokenGenerator.generateWithTurnServerOptions(options));
 
     return new GetCallingRelaysResponse(tokens);

service/src/test/java/org/whispersystems/textsecuregcm/calls/routing/TurnCallRouterTest.java

@@ -162,6 +162,21 @@ public class TurnCallRouterTest {
         ));
   }
 
+  @Test
+  public void testUrlsOnlyNoInstanceIps() throws UnknownHostException {
+    when(performanceTable.getDatacentersFor(any(), any(), any(), any()))
+        .thenReturn(List.of("dc-performance2", "dc-performance1"));
+    when(configTurnRouter.shouldRandomize())
+        .thenReturn(false);
+
+    assertThat(router().getRoutingFor(aci, Optional.of(InetAddress.getByName("0.0.0.1")), 0))
+        .isEqualTo(new TurnServerOptions(
+            TEST_HOSTNAME,
+            null,
+            TEST_URLS_WITH_HOSTS
+        ));
+  }
+
   @Test
   public void testOrderedByPerformance() throws UnknownHostException {
     when(performanceTable.getDatacentersFor(any(), any(), any(), any()))

service/src/test/java/org/whispersystems/textsecuregcm/configuration/dynamic/DynamicConfigurationTest.java

@@ -376,6 +376,23 @@ class DynamicConfigurationTest {
 
       assertThat(turnConfiguration.getHostname()).isEqualTo("test.domain.org");
       assertThat(turnConfiguration.getRandomizeRate()).isEqualTo(100_000L);
+      assertThat(turnConfiguration.getDefaultInstanceIpCount()).isEqualTo(0);
+    }
+
+    {
+      final String config = REQUIRED_CONFIG.concat("""
+          turn:
+            uriConfigs:
+                - uris:
+                    - turn:test0.org
+                    - turn:test1.org
+            defaultInstanceIpCount: 5
+           """);
+      DynamicTurnConfiguration turnConfiguration = DynamicConfigurationManager
+          .parseConfiguration(config, DynamicConfiguration.class)
+          .orElseThrow()
+          .getTurnConfiguration();
+      assertThat(turnConfiguration.getDefaultInstanceIpCount()).isEqualTo(5);
     }
   }
 

service/src/test/java/org/whispersystems/textsecuregcm/controllers/CallRoutingControllerV2Test.java

@@ -34,12 +34,10 @@ import org.whispersystems.textsecuregcm.auth.TurnToken;
 import org.whispersystems.textsecuregcm.auth.TurnTokenGenerator;
 import org.whispersystems.textsecuregcm.calls.routing.TurnCallRouter;
 import org.whispersystems.textsecuregcm.calls.routing.TurnServerOptions;
-import org.whispersystems.textsecuregcm.configuration.dynamic.DynamicConfiguration;
 import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
 import org.whispersystems.textsecuregcm.limits.RateLimiter;
 import org.whispersystems.textsecuregcm.limits.RateLimiters;
 import org.whispersystems.textsecuregcm.mappers.RateLimitExceededExceptionMapper;
-import org.whispersystems.textsecuregcm.storage.DynamicConfigurationManager;
 import org.whispersystems.textsecuregcm.tests.util.AuthHelper;
 import org.whispersystems.textsecuregcm.util.SystemMapper;
 import org.whispersystems.textsecuregcm.util.TestRemoteAddressFilterProvider;
@@ -96,8 +94,7 @@ class CallRoutingControllerV2Test {
       try {
         when(turnCallRouter.getRoutingFor(
             eq(AuthHelper.VALID_UUID),
-            eq(Optional.of(InetAddress.getByName(REMOTE_ADDRESS))),
+            eq(Optional.of(InetAddress.getByName(REMOTE_ADDRESS))))
-            anyInt())
         ).thenReturn(options);
       } catch (UnknownHostException ignored) {
       }
@@ -177,8 +174,7 @@ class CallRoutingControllerV2Test {
 
     when(turnCallRouter.getRoutingFor(
         eq(AuthHelper.VALID_UUID),
-        eq(Optional.of(InetAddress.getByName(REMOTE_ADDRESS))),
+        eq(Optional.of(InetAddress.getByName(REMOTE_ADDRESS))))
-        anyInt())
     ).thenReturn(options);
     try (Response rawResponse = resources.getJerseyTest()
         .target(GET_CALL_RELAYS_PATH)