Fix offset handling in ipv6 parsing (elastic#133192)

Author: felixbarny

muted-tests.yml

@@ -576,24 +576,6 @@ tests:
 - class: org.elasticsearch.xpack.ml.integration.TextEmbeddingQueryIT
   method: testModelWithPrefixStrings
   issue: https://github.com/elastic/elasticsearch/issues/133138
-- class: org.elasticsearch.index.mapper.blockloader.IpFieldBlockLoaderTests
-  method: testBlockLoaderOfMultiField {preference=Params[syntheticSource=true, preference=DOC_VALUES]}
-  issue: https://github.com/elastic/elasticsearch/issues/133149
-- class: org.elasticsearch.index.mapper.blockloader.IpFieldBlockLoaderTests
-  method: testBlockLoaderOfMultiField {preference=Params[syntheticSource=true, preference=STORED]}
-  issue: https://github.com/elastic/elasticsearch/issues/133150
-- class: org.elasticsearch.index.mapper.blockloader.IpFieldBlockLoaderTests
-  method: testBlockLoaderOfMultiField {preference=Params[syntheticSource=true, preference=NONE]}
-  issue: https://github.com/elastic/elasticsearch/issues/133151
-- class: org.elasticsearch.index.mapper.blockloader.IpFieldBlockLoaderTests
-  method: testBlockLoaderForFieldInObject {preference=Params[syntheticSource=true, preference=STORED]}
-  issue: https://github.com/elastic/elasticsearch/issues/133178
-- class: org.elasticsearch.index.mapper.blockloader.IpFieldBlockLoaderTests
-  method: testBlockLoaderForFieldInObject {preference=Params[syntheticSource=true, preference=DOC_VALUES]}
-  issue: https://github.com/elastic/elasticsearch/issues/133179
-- class: org.elasticsearch.index.mapper.blockloader.IpFieldBlockLoaderTests
-  method: testBlockLoaderForFieldInObject {preference=Params[syntheticSource=true, preference=NONE]}
-  issue: https://github.com/elastic/elasticsearch/issues/133180
 - class: org.elasticsearch.test.rest.yaml.CcsCommonYamlTestSuiteIT
   method: test {p0=search.vectors/90_sparse_vector/Indexing and searching multi-value sparse vectors in >=8.15}
   issue: https://github.com/elastic/elasticsearch/issues/133184

server/src/main/java/org/elasticsearch/common/network/InetAddresses.java

@@ -239,8 +239,8 @@ private static byte[] textToNumericFormatV6(byte[] ipUtf8, int offset, int lengt
                 return null; // Invalid character
             }
         }
-        if (currentHextetStart != length) {
-            // Handle the last hextet
+        // Handle the last hextet unless the IP address ends with ::
+        if (currentHextetStart < offset + length) {
             if (putHextet(bytes, currentHextet) == false) {
                 return null;
             }

server/src/test/java/org/elasticsearch/common/network/InetAddressesTests.java

@@ -27,6 +27,7 @@
 import java.net.UnknownHostException;
 import java.nio.charset.StandardCharsets;
 import java.util.Enumeration;
+import java.util.List;
 import java.util.Locale;
 
 import static org.hamcrest.Matchers.equalTo;
@@ -180,10 +181,12 @@ public void testConvertDottedQuadToHex() throws UnknownHostException {
             // Shouldn't hit DNS, because it's an IP string literal.
             InetAddress ipv6Addr = InetAddress.getByName(ipString);
             assertEquals(ipv6Addr, InetAddresses.forString(ipString));
+            int extraLength = randomInt(8);
+            int offset = randomInt(extraLength);
             byte[] asBytes = ipString.getBytes(StandardCharsets.UTF_8);
-            byte[] bytes = new byte[32];
-            System.arraycopy(asBytes, 0, bytes, 8, asBytes.length);
-            assertEquals(ipv6Addr, InetAddresses.forString(bytes, 8, asBytes.length));
+            byte[] bytes = new byte[asBytes.length + extraLength];
+            System.arraycopy(asBytes, 0, bytes, offset, asBytes.length);
+            assertEquals(ipv6Addr, InetAddresses.forString(bytes, offset, asBytes.length));
             assertTrue(InetAddresses.isInetAddress(ipString));
         }
     }
@@ -206,6 +209,35 @@ public void testToAddrStringIPv6() {
         assertEquals("::1", InetAddresses.toAddrString(InetAddresses.forString("0:0:0:0:0:0:0:1")));
         assertEquals("2001:658:22a:cafe::", InetAddresses.toAddrString(InetAddresses.forString("2001:0658:022a:cafe::")));
         assertEquals("::102:304", InetAddresses.toAddrString(InetAddresses.forString("::1.2.3.4")));
+        assertEquals("2001:db8::1:0:0:1", InetAddresses.toAddrString(InetAddresses.forString("2001:db8::1:0:0:1")));
+    }
+
+    public void testWithOffsets() {
+        List<String> ipStrings = List.of(
+            "1:2:3:4:5:6:7:8",
+            "2001:0:0:4::8",
+            "2001::4:5:6:7:8",
+            "2001:0:3:4:5:6:7:8",
+            "0:0:3::ffff",
+            "::4:0:0:0:ffff",
+            "::5:0:0:ffff",
+            "1::4:0:0:7:8",
+            "::",
+            "::1",
+            "2001:658:22a:cafe::",
+            "::102:304",
+            "2001:db8::1:0:0:1",
+            "2001:db8::1:0:1:0"
+        );
+        for (String ipString : ipStrings) {
+            byte[] bytes = ipString.getBytes(StandardCharsets.UTF_8);
+            int extraLength = randomInt(8);
+            int offset = randomInt(extraLength);
+            byte[] bytesWithPadding = new byte[bytes.length + extraLength];
+            System.arraycopy(bytes, 0, bytesWithPadding, offset, bytes.length);
+            InetAddress addr = InetAddresses.forString(bytesWithPadding, offset, bytes.length);
+            assertEquals(ipString, InetAddresses.toAddrString(addr));
+        }
     }
 
     public void testToUriStringIPv4() {