Add isLoopback and isLinkLocal to IpAddress

build.sbt

@@ -33,7 +33,9 @@ ThisBuild / mimaBinaryIssueFilters ++= Seq(
   ProblemFilters.exclude[MissingTypesProblem]("com.comcast.ip4s.Multicast$"),
   ProblemFilters.exclude[DirectMissingMethodProblem]("com.comcast.ip4s.SourceSpecificMulticast.ordinal"),
   ProblemFilters.exclude[MissingTypesProblem]("com.comcast.ip4s.SourceSpecificMulticast$"),
-  ProblemFilters.exclude[ReversedMissingMethodProblem]("com.comcast.ip4s.IpAddress.isPrivate") // #562
+  ProblemFilters.exclude[ReversedMissingMethodProblem]("com.comcast.ip4s.IpAddress.isPrivate"), // #562
+  ProblemFilters.exclude[ReversedMissingMethodProblem]("com.comcast.ip4s.IpAddress.isLoopback"),
+  ProblemFilters.exclude[ReversedMissingMethodProblem]("com.comcast.ip4s.IpAddress.isLinkLocal")
 )
 
 lazy val root = tlCrossRootProject.aggregate(core, testKit)

shared/src/main/scala/com/comcast/ip4s/Host.scala

@@ -215,6 +215,12 @@ sealed abstract class IpAddress extends IpAddressPlatform with Host with Seriali
   def asSourceSpecificMulticastLenient: Option[SourceSpecificMulticast[this.type]] =
     SourceSpecificMulticast.fromIpAddressLenient(this)
 
+  /** Returns true if this address is a loopback address. */
+  def isLoopback: Boolean
+
+  /** Returns true if this address is a link local address. */
+  def isLinkLocal: Boolean
+
   /** Returns true if this address is in a private range. */
   def isPrivate: Boolean
 
@@ -359,6 +365,12 @@ final class Ipv4Address private (protected val bytes: Array[Byte]) extends IpAdd
   override def isSourceSpecificMulticast: Boolean =
     this >= Ipv4Address.SourceSpecificMulticastRangeStart && this <= Ipv4Address.SourceSpecificMulticastRangeEnd
 
+  override def isLoopback: Boolean =
+    Ipv4Address.Classes.Loopback.contains(this)
+
+  override def isLinkLocal: Boolean =
+    Ipv4Address.Classes.LinkLocal.contains(this)
+
   override def isPrivate: Boolean =
     Ipv4Address.Classes.Private.A.contains(this) ||
       Ipv4Address.Classes.Private.B.contains(this) ||
@@ -456,6 +468,12 @@ object Ipv4Address extends Ipv4AddressCompanionPlatform {
       /** Class A: 192.168.0.0 - 192.168.255.255 */
       val C: Cidr[Ipv4Address] = Cidr(fromBytes(192, 168, 0, 0), 16)
     }
+
+    /** Loopback: 127.0.0.0 - 127.255.255.255. */
+    val Loopback: Cidr[Ipv4Address] = Cidr(fromBytes(127, 0, 0, 0), 8)
+
+    /** Link local: 169.254.0.0 - 169.254.255.255. */
+    val LinkLocal: Cidr[Ipv4Address] = Cidr(fromBytes(169, 254, 0, 0), 16)
   }
 
   /** Parses an IPv4 address from a dotted-decimal string, returning `None` if the string is not a valid IPv4 address.
@@ -649,6 +667,12 @@ final class Ipv6Address private (protected val bytes: Array[Byte]) extends IpAdd
   override def isSourceSpecificMulticast: Boolean =
     this >= Ipv6Address.SourceSpecificMulticastRangeStart && this <= Ipv6Address.SourceSpecificMulticastRangeEnd
 
+  override def isLoopback: Boolean =
+    this == Ipv6Address.Loopback || (isMappedV4 && collapseMappedV4.isLoopback)
+
+  override def isLinkLocal: Boolean =
+    Ipv6Address.LinkLocalBlock.contains(this) || (isMappedV4 && collapseMappedV4.isLinkLocal)
+
   override def isPrivate: Boolean =
     Ipv6Address.UniqueLocalBlock.contains(this) || (isMappedV4 && collapseMappedV4.isPrivate)
 
@@ -696,10 +720,17 @@ object Ipv6Address extends Ipv6AddressCompanionPlatform {
   val MappedV4Block: Cidr[Ipv6Address] =
     Cidr(Ipv6Address.fromBytes(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 0, 0, 0, 0), 96)
 
-  /** CIDR which defines unique local address block. */
+  /** Alias for ::1. */
+  val Loopback: Ipv6Address = Ipv6Address.fromBytes(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1)
+
+  /** CIDR which defines the unique local address block. */
   val UniqueLocalBlock: Cidr[Ipv6Address] =
     Cidr(Ipv6Address.fromBytes(0xfc, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0), 7)
 
+  /** CIDR which defines the linked scope unicast address block. */
+  val LinkLocalBlock: Cidr[Ipv6Address] =
+    Cidr(Ipv6Address.fromBytes(0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0), 10)
+
   /** Parses an IPv6 address from a string in RFC4291 notation, returning `None` if the string is not a valid IPv6
     * address.
     */

test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv4AddressTest.scala

@@ -84,4 +84,17 @@ class Ipv4AddressTest extends BaseTestSuite {
     assert(ipv4"192.168.255.255".isPrivate)
     assert(!ipv4"192.168.255.255".next.isPrivate)
   }
+
+  test("isLoopback") {
+    assert(ipv4"127.0.0.1".isLoopback)
+    assert(ipv4"127.255.255.255".isLoopback)
+    assert(!ipv4"128.0.0.0".isLoopback)
+  }
+
+  test("isLinkLocal") {
+    assert(!ipv4"127.0.0.1".isLinkLocal)
+    assert(ipv4"169.254.0.0".isLinkLocal)
+    assert(ipv4"169.254.255.255".isLinkLocal)
+    assert(!ipv4"169.254.255.255".next.isLinkLocal)
+  }
 }

test-kit/shared/src/test/scala/com/comcast/ip4s/Ipv6AddressTest.scala

@@ -140,4 +140,14 @@ class Ipv6AddressTest extends BaseTestSuite {
     // mapped v4
     assert(ipv6"::ffff:10.1.1.1".isPrivate)
   }
+
+  test("isLoopback") {
+    assert(ipv6"::1".isLoopback)
+    assert(ipv6"::ffff:127.0.0.1".isLoopback)
+  }
+
+  test("isLinkLocal") {
+    assert(ipv6"fe80::1".isLinkLocal)
+    assert(ipv6"::ffff:169.254.0.0".isLinkLocal)
+  }
 }