Overload lines in extra info descriptors.

* Checks that the overload keys are seen at most once
* Exposes the version fields from each line
* Exposes the rate and burst limits from overload-ratelimit
* Checks that the line has all the fields present

src/main/java/org/torproject/descriptor/ExtraInfoDescriptor.java

@@ -122,6 +122,13 @@ public interface ExtraInfoDescriptor extends Descriptor {
    */
   BandwidthHistory getIpv6ReadHistory();
 
+  /**
+   * Return the version number in the overload-ratelimits line.
+   *
+   * @since 2.18.0
+   */
+  long getOverloadRatelimitsVersion();
+
   /**
    * Return the server's history exhausted bandwidth as a timestamp of the
    * last time this happened, or -1 if the descriptor does not
@@ -131,6 +138,22 @@ public interface ExtraInfoDescriptor extends Descriptor {
    */
   long getOverloadRatelimitsTimestamp();
 
+  /**
+   * Return the server's rate-limit, or -1 if the descriptor does not
+   * contain a bandwidth overload rate limit.
+   *
+   * @since 2.18.0
+   */
+  long getOverloadRatelimitsRateLimit();
+
+  /**
+   * Return the server's burst-limit, or -1 if the descriptor does not
+   * contain a bandwidth overload rate limit.
+   *
+   * @since 2.18.0
+   */
+  long getOverloadRatelimitsBurstLimit();
+
   /**
    * Return the server's read-overload-count, or -1 if the descriptor does not
    * contain a bandwidth overload rate limit.
@@ -147,12 +170,19 @@ public interface ExtraInfoDescriptor extends Descriptor {
    */
   int getOverloadRatelimitsWriteCount();
 
+  /**
+   * Return the version number in the overload-fd-exhausted line.
+   *
+   * @since 2.18.0
+   */
+  int getOverloadFdExhaustedVersion();
+
   /**
    * Return the server's  descriptor exhaustion as a timestamp.
    * The timestamp indicates that the maximum was reached between the
    * timestamp and the "published" timestamp of the document.
    *
-   * -1 is returned if the descriptor does not contain a file descriptor
+   * <p>-1 is returned if the descriptor does not contain a file descriptor
    * exhaustion.
    *
    * @since 2.18.0

src/main/java/org/torproject/descriptor/impl/ExtraInfoDescriptorImpl.java

@@ -33,7 +33,7 @@ public abstract class ExtraInfoDescriptorImpl extends DescriptorImpl
       Key.WRITE_HISTORY, Key.DIRREQ_READ_HISTORY, Key.DIRREQ_WRITE_HISTORY,
       Key.GEOIP_DB_DIGEST, Key.GEOIP6_DB_DIGEST, Key.ROUTER_SIG_ED25519,
       Key.ROUTER_SIGNATURE, Key.ROUTER_DIGEST_SHA256, Key.ROUTER_DIGEST,
-      Key.PADDING_COUNTS);
+      Key.PADDING_COUNTS, Key.OVERLOAD_RATELIMITS, Key.OVERLOAD_FD_EXHAUSTED);
 
   protected ExtraInfoDescriptorImpl(byte[] descriptorBytes,
       int[] offsetAndLimit, File descriptorFile)
@@ -340,24 +340,35 @@ public abstract class ExtraInfoDescriptorImpl extends DescriptorImpl
 
   private void parseOverloadRatelimits(String line,
       String[] partsNoOpt) throws DescriptorParseException {
-    int version = Integer.parseInt(partsNoOpt[1]);
-    if (version != 1) {
-      throw new DescriptorParseException("Illegal version number for line '"
+    this.overloadRatelimitsVersion = Integer.parseInt(partsNoOpt[1]);
+    if (this.overloadRatelimitsVersion != 1) {
+      throw new DescriptorParseException("Unknown version number for line '"
               + line + "' in extra-info descriptor.");
     }
+    if (partsNoOpt.length < 8) {
+      throw new DescriptorParseException("Missing fields for line '"
+          + line + "' in extra-info descriptor.");
+    }
     this.overloadRatelimitsTimestamp = ParseHelper.parseTimestampAtIndex(line,
         partsNoOpt, 2, 3);
+    this.overloadRatelimitsRateLimit = Long.parseLong(partsNoOpt[4]);
+    this.overloadRatelimitsBurstLimit = Long.parseLong(partsNoOpt[5]);
     this.overloadRatelimitsReadCount = Integer.parseInt(partsNoOpt[6]);
     this.overloadRatelimitsWriteCount = Integer.parseInt(partsNoOpt[7]);
   }
 
   private void parseOverloadFdExhausted(String line,
-                                       String[] partsNoOpt) throws DescriptorParseException {
-    int version = Integer.parseInt(partsNoOpt[1]);
-    if (version != 1) {
+                                       String[] partsNoOpt)
+      throws DescriptorParseException {
+    this.overloadFdExhaustedVersion = Integer.parseInt(partsNoOpt[1]);
+    if (this.overloadFdExhaustedVersion != 1) {
       throw new DescriptorParseException("Illegal version number for line '"
               + line + "' in extra-info descriptor.");
     }
+    if (partsNoOpt.length < 4) {
+      throw new DescriptorParseException("Missing fields for line '"
+          + line + "' in extra-info descriptor.");
+    }
     this.overloadFdExhaustedTimestamp = ParseHelper.parseTimestampAtIndex(line,
             partsNoOpt, 2, 3);
   }
@@ -983,6 +994,13 @@ public abstract class ExtraInfoDescriptorImpl extends DescriptorImpl
     return this.geoip6DbDigest;
   }
 
+  private int overloadRatelimitsVersion = 0;
+
+  @Override
+  public long getOverloadRatelimitsVersion() {
+    return this.overloadRatelimitsVersion;
+  }
+
   private long overloadRatelimitsTimestamp = -1L;
 
   @Override
@@ -990,6 +1008,20 @@ public abstract class ExtraInfoDescriptorImpl extends DescriptorImpl
     return this.overloadRatelimitsTimestamp;
   }
 
+  private long overloadRatelimitsRateLimit = -1L;
+
+  @Override
+  public long getOverloadRatelimitsRateLimit() {
+    return this.overloadRatelimitsRateLimit;
+  }
+
+  private long overloadRatelimitsBurstLimit = -1L;
+
+  @Override
+  public long getOverloadRatelimitsBurstLimit() {
+    return this.overloadRatelimitsBurstLimit;
+  }
+
   private int overloadRatelimitsReadCount = -1;
 
   @Override
@@ -1004,6 +1036,13 @@ public abstract class ExtraInfoDescriptorImpl extends DescriptorImpl
     return this.overloadRatelimitsWriteCount;
   }
 
+  private int overloadFdExhaustedVersion = 0;
+
+  @Override
+  public int getOverloadFdExhaustedVersion() {
+    return this.overloadFdExhaustedVersion;
+  }
+
   private long overloadFdExhaustedTimestamp = -1L;
 
   @Override