Fixes #402 - allows source specific multicast ranges outside RFC range

build.sbt

@@ -25,7 +25,12 @@ ThisBuild / initialCommands := "import com.comcast.ip4s._"
 
 ThisBuild / mimaBinaryIssueFilters ++= Seq(
   ProblemFilters.exclude[DirectMissingMethodProblem]("com.comcast.ip4s.Ipv6Address.toInetAddress"),
-  ProblemFilters.exclude[ReversedMissingMethodProblem]("com.comcast.ip4s.Dns.*") // sealed trait
+  ProblemFilters.exclude[ReversedMissingMethodProblem]("com.comcast.ip4s.Dns.*"), // sealed trait
+  // Scala 3 (erroneously?) considered Multicast/SourceSpecificMulticast as sum types
+  ProblemFilters.exclude[DirectMissingMethodProblem]("com.comcast.ip4s.Multicast.ordinal"),
+  ProblemFilters.exclude[MissingTypesProblem]("com.comcast.ip4s.Multicast$"),
+  ProblemFilters.exclude[DirectMissingMethodProblem]("com.comcast.ip4s.SourceSpecificMulticast.ordinal"),
+  ProblemFilters.exclude[MissingTypesProblem]("com.comcast.ip4s.SourceSpecificMulticast$")
 )
 
 lazy val root = tlCrossRootProject.aggregate(core, testKit)
@@ -93,8 +98,8 @@ lazy val docs = project
   .settings(
     mdocIn := baseDirectory.value / "src",
     mdocOut := baseDirectory.value / "../docs",
-    crossScalaVersions := (ThisBuild / crossScalaVersions).value.filter(_.startsWith("2.")),
-    githubWorkflowArtifactUpload := false
+    githubWorkflowArtifactUpload := false,
+    libraryDependencies += "org.typelevel" %%% "cats-effect" % "3.3.11"
   )
 
 lazy val commonSettings = Seq(

docs/guide.md

@@ -102,7 +102,7 @@ val homeIA = ip"127.0.0.1".toInetAddress
 val home4IA = ipv4"127.0.0.1".toInetAddress
 // home4IA: java.net.Inet4Address = /127.0.0.1
 val home6IA = ipv6"::1".toInetAddress
-// home6IA: java.net.Inet6Address = /0:0:0:0:0:0:0:1
+// home6IA: java.net.InetAddress = /0:0:0:0:0:0:0:1
 ```
 
 # Multicast
@@ -135,9 +135,18 @@ To construct instances of `Multicast[A]` and `SourceSpecificMulticast[A]`, we ca
 val multicastIps = ips.flatMap(_.asMulticast)
 // multicastIps: List[com.comcast.ip4s.Multicast[IpAddress]] = List(224.10.10.10, 232.11.11.11, ff00::10, ff3b::11)
 val ssmIps = ips.flatMap(_.asSourceSpecificMulticast)
-// ssmIps: List[com.comcast.ip4s.SourceSpecificMulticast[IpAddress]] = List(232.11.11.11, ff3b::11)
+// ssmIps: List[SourceSpecificMulticast.Strict[IpAddress]] = List(232.11.11.11, ff3b::11)
 ```
 
+It's common for source specific multicast to be used with group addresses outside the designated source specific multicast address range. To support such cases, use `asSourceSpecificMulticastLenient`:
+
+```scala
+val lenient = ips.flatMap(_.asSourceSpecificMulticastLenient)
+// lenient: List[com.comcast.ip4s.SourceSpecificMulticast[IpAddress]] = List(224.10.10.10, 232.11.11.11, ff00::10, ff3b::11)
+```
+
+Additionally, the `SourceSpecificMulticast.Strict[A]` type provides the guarantee that the wrapped address is in the RFC defined source specific range.
+
 ## Multicast Literals
 
 There are string interpolators for constructing multicast and source specific multicast address from literal strings, similar to the `ip`, `ipv4`, and `ipv6` interpolators. The multicast interpolators are:
@@ -259,7 +268,7 @@ On the JVM, a `SocketAddress` can be converted to a `java.net.InetSocketAddress`
 
 ```scala
 val u = t.toInetSocketAddress
-// u: java.net.InetSocketAddress = /0:0:0:0:0:0:0:1:5555
+// u: java.net.InetSocketAddress = /[0:0:0:0:0:0:0:1]:5555
 ```
 
 ## Multicast Socket Addresses

docs/src/guide.md

@@ -114,6 +114,14 @@ val multicastIps = ips.flatMap(_.asMulticast)
 val ssmIps = ips.flatMap(_.asSourceSpecificMulticast)
 ```
 
+It's common for source specific multicast to be used with group addresses outside the designated source specific multicast address range. To support such cases, use `asSourceSpecificMulticastLenient`:
+
+```scala mdoc:nest:to-string
+val lenient = ips.flatMap(_.asSourceSpecificMulticastLenient)
+```
+
+Additionally, the `SourceSpecificMulticast.Strict[A]` type provides the guarantee that the wrapped address is in the RFC defined source specific range.
+
 ## Multicast Literals
 
 There are string interpolators for constructing multicast and source specific multicast address from literal strings, similar to the `ip`, `ipv4`, and `ipv6` interpolators. The multicast interpolators are:

shared/src/main/scala-2/Literals.scala

@@ -87,7 +87,7 @@ object Literals {
     def make(c: Context)(args: c.Expr[Any]*): c.Expr[Multicast[Ipv6Address]] = apply(c)(args: _*)
   }
 
-  object ssmip extends Literally[SourceSpecificMulticast[IpAddress]] {
+  object ssmip extends Literally[SourceSpecificMulticast.Strict[IpAddress]] {
     def validate(c: Context)(s: String) = {
       import c.universe._
       IpAddress.fromString(s).flatMap(_.asSourceSpecificMulticast) match {
@@ -96,10 +96,10 @@ object Literals {
         case None => Left("invalid source specific IP multicast address")
       }
     }
-    def make(c: Context)(args: c.Expr[Any]*): c.Expr[SourceSpecificMulticast[IpAddress]] = apply(c)(args: _*)
+    def make(c: Context)(args: c.Expr[Any]*): c.Expr[SourceSpecificMulticast.Strict[IpAddress]] = apply(c)(args: _*)
   }
 
-  object ssmipv4 extends Literally[SourceSpecificMulticast[Ipv4Address]] {
+  object ssmipv4 extends Literally[SourceSpecificMulticast.Strict[Ipv4Address]] {
     def validate(c: Context)(s: String) = {
       import c.universe._
       Ipv4Address.fromString(s).flatMap(_.asSourceSpecificMulticast) match {
@@ -108,10 +108,10 @@ object Literals {
         case None => Left("invalid source specific IPv4 multicast address")
       }
     }
-    def make(c: Context)(args: c.Expr[Any]*): c.Expr[SourceSpecificMulticast[Ipv4Address]] = apply(c)(args: _*)
+    def make(c: Context)(args: c.Expr[Any]*): c.Expr[SourceSpecificMulticast.Strict[Ipv4Address]] = apply(c)(args: _*)
   }
 
-  object ssmipv6 extends Literally[SourceSpecificMulticast[Ipv6Address]] {
+  object ssmipv6 extends Literally[SourceSpecificMulticast.Strict[Ipv6Address]] {
     def validate(c: Context)(s: String) = {
       import c.universe._
       Ipv6Address.fromString(s).flatMap(_.asSourceSpecificMulticast) match {
@@ -120,7 +120,7 @@ object Literals {
         case None => Left("invalid source specific IPv6 multicast address")
       }
     }
-    def make(c: Context)(args: c.Expr[Any]*): c.Expr[SourceSpecificMulticast[Ipv6Address]] = apply(c)(args: _*)
+    def make(c: Context)(args: c.Expr[Any]*): c.Expr[SourceSpecificMulticast.Strict[Ipv6Address]] = apply(c)(args: _*)
   }
 
   object port extends Literally[Port] {

shared/src/main/scala-2/package.scala

@@ -31,11 +31,11 @@ package object ip4s extends ip4splatform {
     def mipv6(args: Any*): Multicast[Ipv6Address] =
       macro Literals.mipv6.make
 
-    def ssmip(args: Any*): SourceSpecificMulticast[IpAddress] =
+    def ssmip(args: Any*): SourceSpecificMulticast.Strict[IpAddress] =
       macro Literals.ssmip.make
-    def ssmipv4(args: Any*): SourceSpecificMulticast[Ipv4Address] =
+    def ssmipv4(args: Any*): SourceSpecificMulticast.Strict[Ipv4Address] =
       macro Literals.ssmipv4.make
-    def ssmipv6(args: Any*): SourceSpecificMulticast[Ipv6Address] =
+    def ssmipv6(args: Any*): SourceSpecificMulticast.Strict[Ipv6Address] =
       macro Literals.ssmipv6.make
 
     def port(args: Any*): Port =

shared/src/main/scala-3/Literals.scala

@@ -37,13 +37,13 @@ extension (inline ctx: StringContext)
   inline def mipv6(inline args: Any*): Multicast[Ipv6Address] =
     ${ Literals.mipv6('ctx, 'args) }
 
-  inline def ssmip(inline args: Any*): SourceSpecificMulticast[IpAddress] =
+  inline def ssmip(inline args: Any*): SourceSpecificMulticast.Strict[IpAddress] =
     ${ Literals.ssmip('ctx, 'args) }
 
-  inline def ssmipv4(inline args: Any*): SourceSpecificMulticast[Ipv4Address] =
+  inline def ssmipv4(inline args: Any*): SourceSpecificMulticast.Strict[Ipv4Address] =
     ${ Literals.ssmipv4('ctx, 'args) }
 
-  inline def ssmipv6(inline args: Any*): SourceSpecificMulticast[Ipv6Address] =
+  inline def ssmipv6(inline args: Any*): SourceSpecificMulticast.Strict[Ipv6Address] =
     ${ Literals.ssmipv6('ctx, 'args) }
 
   inline def port(inline args: Any*): Port =
@@ -93,25 +93,31 @@ object Literals:
         case Some(_) => Right('{ _root_.com.comcast.ip4s.Ipv6Address.fromString(${ Expr(s) }).get.asMulticast.get })
         case None    => Left("Invalid IPv6 multicast address")
 
-  object ssmip extends Literally[SourceSpecificMulticast[IpAddress]]:
+  object ssmip extends Literally[SourceSpecificMulticast.Strict[IpAddress]]:
     def validate(s: String)(using Quotes) =
       IpAddress.fromString(s).flatMap(_.asSourceSpecificMulticast) match
         case Some(_) =>
-          Right('{ _root_.com.comcast.ip4s.IpAddress.fromString(${ Expr(s) }).get.asSourceSpecificMulticast.get })
+          Right('{
+            _root_.com.comcast.ip4s.IpAddress.fromString(${ Expr(s) }).get.asSourceSpecificMulticast.get
+          })
         case None => Left("Invalid source specific IP multicast address")
 
-  object ssmipv4 extends Literally[SourceSpecificMulticast[Ipv4Address]]:
+  object ssmipv4 extends Literally[SourceSpecificMulticast.Strict[Ipv4Address]]:
     def validate(s: String)(using Quotes) =
       Ipv4Address.fromString(s).flatMap(_.asSourceSpecificMulticast) match
         case Some(_) =>
-          Right('{ _root_.com.comcast.ip4s.Ipv4Address.fromString(${ Expr(s) }).get.asSourceSpecificMulticast.get })
+          Right('{
+            _root_.com.comcast.ip4s.Ipv4Address.fromString(${ Expr(s) }).get.asSourceSpecificMulticast.get
+          })
         case None => Left("Invalid source specific IPv4 multicast address")
 
-  object ssmipv6 extends Literally[SourceSpecificMulticast[Ipv6Address]]:
+  object ssmipv6 extends Literally[SourceSpecificMulticast.Strict[Ipv6Address]]:
     def validate(s: String)(using Quotes) =
       Ipv6Address.fromString(s).flatMap(_.asSourceSpecificMulticast) match
         case Some(_) =>
-          Right('{ _root_.com.comcast.ip4s.Ipv6Address.fromString(${ Expr(s) }).get.asSourceSpecificMulticast.get })
+          Right('{
+            _root_.com.comcast.ip4s.Ipv6Address.fromString(${ Expr(s) }).get.asSourceSpecificMulticast.get
+          })
         case None => Left("Invalid source specific IPv6 multicast address")
 
   object port extends Literally[Port]:

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

@@ -175,9 +175,13 @@ sealed abstract class IpAddress extends IpAddressPlatform with Host with Seriali
   /** Converts this address to a source specific multicast address, as long as it is in the source specific multicast
     * address range.
     */
-  def asSourceSpecificMulticast: Option[SourceSpecificMulticast[this.type]] =
+  def asSourceSpecificMulticast: Option[SourceSpecificMulticast.Strict[this.type]] =
     SourceSpecificMulticast.fromIpAddress(this)
 
+  /** Like `asSourceSpecificMulticast` but allows multicast addresses outside the source specific range. */
+  def asSourceSpecificMulticastLenient: Option[SourceSpecificMulticast[this.type]] =
+    SourceSpecificMulticast.fromIpAddressLenient(this)
+
   /** Narrows this address to an Ipv4Address if that is the underlying type. */
   def asIpv4: Option[Ipv4Address] = collapseMappedV4.fold(Some(_), _ => None)
 

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

@@ -30,6 +30,11 @@ sealed trait Multicast[+A <: IpAddress] extends Product with Serializable {
 object Multicast {
   private case class DefaultMulticast[+A <: IpAddress](address: A) extends Multicast[A] {
     override def toString: String = address.toString
+    override def equals(that: Any): Boolean = that match {
+      case m: Multicast[_] => address == m.address
+      case _               => false
+    }
+    override def hashCode: Int = address.hashCode
   }
 
   /** Constructs a multicast IP address. Returns `None` is the supplied address is not in the valid multicast range. */
@@ -47,27 +52,50 @@ object Multicast {
 
 /** Witnesses that the wrapped address of type `A` is a source specific multicast address.
   *
-  * An instance of `SourceSpecificMulticast` is typically created by either calling `Multicast.apply` or by using the
-  * `asSourceSpecificMulticast` method on `IpAddress`.
+  * An instance of `SourceSpecificMulticast` is typically created by either calling `Multicast.apply` or by using
+  * `asSourceSpecificMulticast` and `asSourceSpecificMulticastLenient` methods on `IpAddress`.
   */
 sealed trait SourceSpecificMulticast[+A <: IpAddress] extends Multicast[A] {
+
+  /** Ensures the referenced address is in the RFC defined source specific address range. */
+  def strict: Option[SourceSpecificMulticast.Strict[A]] =
+    if (address.isSourceSpecificMulticast) Some(SourceSpecificMulticast.unsafeCreateStrict(address)) else None
+
   override def toString: String = address.toString
 }
 
 object SourceSpecificMulticast {
+
+  /** Indicates the address is within the RFC defined source specific multicast range. */
+  trait Strict[+A <: IpAddress] extends SourceSpecificMulticast[A]
+
   private case class DefaultSourceSpecificMulticast[+A <: IpAddress](address: A) extends SourceSpecificMulticast[A] {
     override def toString: String = address.toString
+    override def equals(that: Any): Boolean = that match {
+      case m: Multicast[_] => address == m.address
+      case _               => false
+    }
+    override def hashCode: Int = address.hashCode
   }
 
-  /** Constructs a source specific multicast IP address. Returns `None` is the supplied address is not in the valid
+  /** Constructs a source specific multicast IP address. Returns `None` if the supplied address is not in the valid
     * source specific multicast range.
     */
-  def fromIpAddress[A <: IpAddress](address: A): Option[SourceSpecificMulticast[A]] =
-    if (address.isSourceSpecificMulticast) Some(new DefaultSourceSpecificMulticast(address)) else None
+  def fromIpAddress[A <: IpAddress](address: A): Option[SourceSpecificMulticast.Strict[A]] =
+    if (address.isSourceSpecificMulticast) Some(unsafeCreateStrict(address)) else None
+
+  /** Constructs a source specific multicast IP address. Unlike `fromIpAddress`, multicast addresses outside the RFC
+    * defined source specific range are allowed.
+    */
+  def fromIpAddressLenient[A <: IpAddress](address: A): Option[SourceSpecificMulticast[A]] =
+    if (address.isMulticast) Some(unsafeCreate(address)) else None
 
   private[ip4s] def unsafeCreate[A <: IpAddress](address: A): SourceSpecificMulticast[A] =
     DefaultSourceSpecificMulticast(address)
 
+  private[ip4s] def unsafeCreateStrict[A <: IpAddress](address: A): SourceSpecificMulticast.Strict[A] =
+    new DefaultSourceSpecificMulticast(address) with Strict[A]
+
   implicit def ordering[A <: IpAddress]: Ordering[SourceSpecificMulticast[A]] =
     Multicast.ordering[SourceSpecificMulticast, A]
 }

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

@@ -80,11 +80,11 @@ object MulticastJoin {
           case Some(sourceStr) =>
             for {
               source <- parse(sourceStr)
-              group <- parse(groupStr).flatMap(_.asSourceSpecificMulticast)
+              group <- parse(groupStr).flatMap(_.asSourceSpecificMulticastLenient)
             } yield ssm(source, group)
           case None =>
             for {
-              group <- parse(groupStr).flatMap(_.asSourceSpecificMulticast)
+              group <- parse(groupStr).flatMap(_.asSourceSpecificMulticastLenient)
             } yield asm(group)
         }
       case _ => None

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

@@ -88,7 +88,7 @@ object MulticastSocketAddress {
           case Some(sourceStr) =>
             for {
               source <- parse(sourceStr)
-              group <- parse(groupStr).flatMap(_.asSourceSpecificMulticast)
+              group <- parse(groupStr).flatMap(_.asSourceSpecificMulticastLenient)
               port <- Port.fromString(portStr)
             } yield MulticastSocketAddress(MulticastJoin.ssm(source, group), port)
           case None =>

test-kit/shared/src/main/scala/com/comcast/ip4s/Arbitraries.scala

@@ -80,8 +80,9 @@ object Arbitraries {
   def multicastJoinGenerator[A <: IpAddress](genSource: Gen[A], genGroup: Gen[Multicast[A]]): Gen[MulticastJoin[A]] =
     genGroup.flatMap { group =>
       group.address.asSourceSpecificMulticast match {
-        case Some(grp) => genSource.filter(_.getClass == grp.getClass).flatMap(src => MulticastJoin.ssm(src, grp))
-        case None      => MulticastJoin.asm(group)
+        case Some(grp) =>
+          genSource.filter(_.getClass == grp.address.getClass).flatMap(src => MulticastJoin.ssm(src, grp))
+        case None => MulticastJoin.asm(group)
       }
     }
 

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

@@ -23,8 +23,16 @@ class MulticastTest extends BaseTestSuite {
   test("support equality") {
     forAll { (mip: Multicast[IpAddress]) =>
       assertEquals(mip.address.asMulticast, Some(mip))
-      mip.address.asSourceSpecificMulticast.foreach(x => assert(x == mip))
-      mip.address.asSourceSpecificMulticast.foreach(x => assertEquals(mip, x))
+      mip.address.asSourceSpecificMulticastLenient.foreach(x => assertEquals(mip, x))
+      mip.address.asSourceSpecificMulticastLenient.foreach(x => assert(x == mip))
     }
   }
+
+  test("support SSM outside source specific range") {
+    assertEquals(ip"239.10.10.10".asSourceSpecificMulticast, None)
+    assertEquals(
+      ip"239.10.10.10".asSourceSpecificMulticastLenient,
+      Some(SourceSpecificMulticast.unsafeCreate(ip"239.10.10.10"))
+    )
+  }
 }