Add a prefix limiter

src/main/java/org/whispersystems/textsecuregcm/configuration/RateLimitsConfiguration.java

@@ -32,6 +32,9 @@ public class RateLimitsConfiguration {
   @JsonProperty
   private RateLimitConfiguration smsVoiceIp = new RateLimitConfiguration(1000, 1000);
 
+  @JsonProperty
+  private RateLimitConfiguration smsVoicePrefix = new RateLimitConfiguration(1000, 1000);
+
   @JsonProperty
   private RateLimitConfiguration verifyNumber = new RateLimitConfiguration(2, 2);
 
@@ -102,6 +105,10 @@ public class RateLimitsConfiguration {
     return smsVoiceIp;
   }
 
+  public RateLimitConfiguration getSmsVoicePrefix() {
+    return smsVoicePrefix;
+  }
+
   public RateLimitConfiguration getVerifyNumber() {
     return verifyNumber;
   }

src/main/java/org/whispersystems/textsecuregcm/controllers/AccountController.java

@@ -85,9 +85,12 @@ public class AccountController {
   private final Meter          newUserMeter           = metricRegistry.meter(name(AccountController.class, "brand_new_user"     ));
   private final Meter          blockedHostMeter       = metricRegistry.meter(name(AccountController.class, "blocked_host"       ));
   private final Meter          filteredHostMeter      = metricRegistry.meter(name(AccountController.class, "filtered_host"      ));
+  private final Meter          rateLimitedHostMeter   = metricRegistry.meter(name(AccountController.class, "rate_limited_host"  ));
+  private final Meter          rateLimitedPrefixMeter = metricRegistry.meter(name(AccountController.class, "rate_limited_prefix"));
   private final Meter          captchaSuccessMeter    = metricRegistry.meter(name(AccountController.class, "captcha_success"    ));
   private final Meter          captchaFailureMeter    = metricRegistry.meter(name(AccountController.class, "captcha_failure"    ));
 
+
   private final PendingAccountsManager                pendingAccounts;
   private final AccountsManager                       accounts;
   private final AbusiveHostRules                      abusiveHostRules;
@@ -420,10 +423,19 @@ public class AccountController {
         rateLimiters.getSmsVoiceIpLimiter().validate(requester);
       } catch (RateLimitExceededException e) {
         logger.info("Rate limited exceeded: " + transport + ", " + number + ", " + requester + " (" + forwardedFor + ")");
+        rateLimitedPrefixMeter.mark();
         return true;
       }
     }
 
+    try {
+      rateLimiters.getSmsVoicePrefixLimiter().validate(Util.getNumberPrefix(number));
+    } catch (RateLimitExceededException e) {
+      logger.info("Prefix rate limit exceeded: " + transport + ", " + number + ", (" + String.join(", ", requesters) + ")");
+      rateLimitedPrefixMeter.mark();
+      return true;
+    }
+
     return false;
   }
 

src/main/java/org/whispersystems/textsecuregcm/limits/RateLimiters.java

@@ -26,6 +26,7 @@ public class RateLimiters {
   private final RateLimiter voiceDestinationLimiter;
   private final RateLimiter voiceDestinationDailyLimiter;
   private final RateLimiter smsVoiceIpLimiter;
+  private final RateLimiter smsVoicePrefixLimiter;
   private final RateLimiter verifyLimiter;
   private final RateLimiter pinLimiter;
 
@@ -58,6 +59,10 @@ public class RateLimiters {
                                              config.getSmsVoiceIp().getBucketSize(),
                                              config.getSmsVoiceIp().getLeakRatePerMinute());
 
+    this.smsVoicePrefixLimiter = new RateLimiter(cacheClient, "smsVoicePrefix",
+                                                 config.getSmsVoicePrefix().getBucketSize(),
+                                                 config.getSmsVoicePrefix().getLeakRatePerMinute());
+
     this.verifyLimiter = new RateLimiter(cacheClient, "verify",
                                          config.getVerifyNumber().getBucketSize(),
                                          config.getVerifyNumber().getLeakRatePerMinute());
@@ -131,6 +136,10 @@ public class RateLimiters {
     return smsVoiceIpLimiter;
   }
 
+  public RateLimiter getSmsVoicePrefixLimiter() {
+    return smsVoicePrefixLimiter;
+  }
+
   public RateLimiter getVoiceDestinationLimiter() {
     return voiceDestinationLimiter;
   }

src/main/java/org/whispersystems/textsecuregcm/util/Util.java

@@ -60,6 +60,14 @@ public class Util {
     else                return "0";
   }
 
+  public static String getNumberPrefix(String number) {
+    String countryCode  = getCountryCode(number);
+    int    remaining    = number.length() - (1 + countryCode.length());
+    int    prefixLength = Math.min(4, remaining);
+
+    return number.substring(0, 1 + countryCode.length() + prefixLength);
+  }
+
   public static String encodeFormParams(Map<String, String> params) {
     try {
       StringBuffer buffer = new StringBuffer();

src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AccountControllerTest.java

@@ -63,6 +63,7 @@ public class AccountControllerTest {
   private        RateLimiter            rateLimiter            = mock(RateLimiter.class           );
   private        RateLimiter            pinLimiter             = mock(RateLimiter.class           );
   private        RateLimiter            smsVoiceIpLimiter      = mock(RateLimiter.class           );
+  private        RateLimiter            smsVoicePrefixLimiter  = mock(RateLimiter.class);
   private        SmsSender              smsSender              = mock(SmsSender.class             );
   private        DirectoryQueue         directoryQueue         = mock(DirectoryQueue.class);
   private        MessagesManager        storedMessages         = mock(MessagesManager.class       );
@@ -98,6 +99,7 @@ public class AccountControllerTest {
     when(rateLimiters.getVerifyLimiter()).thenReturn(rateLimiter);
     when(rateLimiters.getPinLimiter()).thenReturn(pinLimiter);
     when(rateLimiters.getSmsVoiceIpLimiter()).thenReturn(smsVoiceIpLimiter);
+    when(rateLimiters.getSmsVoicePrefixLimiter()).thenReturn(smsVoicePrefixLimiter);
 
     when(timeProvider.getCurrentTimeMillis()).thenReturn(System.currentTimeMillis());
 

src/test/java/org/whispersystems/textsecuregcm/tests/util/NumberPrefixTest.java

@@ -0,0 +1,18 @@
+package org.whispersystems.textsecuregcm.tests.util;
+
+import org.junit.Test;
+import org.whispersystems.textsecuregcm.util.Util;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+public class NumberPrefixTest {
+
+  @Test
+  public void testPrefixes() {
+    assertThat(Util.getNumberPrefix("+14151234567")).isEqualTo("+14151");
+    assertThat(Util.getNumberPrefix("+22587654321")).isEqualTo("+2258765");
+    assertThat(Util.getNumberPrefix("+298654321")).isEqualTo("+2986543");
+    assertThat(Util.getNumberPrefix("+12")).isEqualTo("+12");
+  }
+
+}