From 97b14f3150ee9448401478684dbd268bf807bed1 Mon Sep 17 00:00:00 2001
From: nikiforo <anikiforov@delimobil.ru>
Date: Tue, 7 Dec 2021 21:01:26 +0300
Subject: [PATCH] pcapng - granulate IDB

---
 .../scala/fs2/protocols/pcap/LinkType.scala   |  9 +++++++--
 .../pcapng/InterfaceDescriptionBlock.scala    | 19 ++++++++++++++++---
 .../scala/fs2/protocols/PcapNgExample.scala   |  3 ++-
 .../fs2/protocols/pcapng/BlockTest.scala      |  9 +++++----
 4 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/protocols/shared/src/main/scala/fs2/protocols/pcap/LinkType.scala b/protocols/shared/src/main/scala/fs2/protocols/pcap/LinkType.scala
index 04ecd741a6..b6a14a6aed 100644
--- a/protocols/shared/src/main/scala/fs2/protocols/pcap/LinkType.scala
+++ b/protocols/shared/src/main/scala/fs2/protocols/pcap/LinkType.scala
@@ -41,14 +41,17 @@ object LinkType {
   case object MPEG2TS extends LinkType
   case class Unknown(value: Long) extends LinkType
 
-  def toLong(lt: LinkType): Long = lt match {
+  def fromInt(l: Int): LinkType =
+    fromLong(l)
+
+  def toInt(lt: LinkType): Int = lt match {
     case Null           => 0
     case Ethernet       => 1
     case Raw            => 101
     case IPv4           => 228
     case IPv6           => 229
     case MPEG2TS        => 243
-    case Unknown(value) => value
+    case Unknown(value) => value.toInt // discuss?
   }
 
   def fromLong(l: Long): LinkType = l match {
@@ -61,6 +64,8 @@ object LinkType {
     case other => Unknown(other)
   }
 
+  def toLong(lt: LinkType): Long = toInt(lt)
+
   implicit def codec(implicit bo: ByteOrdering): Codec[LinkType] =
     guint32.xmap[LinkType](fromLong, toLong)
 }
diff --git a/protocols/shared/src/main/scala/fs2/protocols/pcapng/InterfaceDescriptionBlock.scala b/protocols/shared/src/main/scala/fs2/protocols/pcapng/InterfaceDescriptionBlock.scala
index 8ea113079a..2224082f60 100644
--- a/protocols/shared/src/main/scala/fs2/protocols/pcapng/InterfaceDescriptionBlock.scala
+++ b/protocols/shared/src/main/scala/fs2/protocols/pcapng/InterfaceDescriptionBlock.scala
@@ -22,17 +22,30 @@
 package fs2.protocols
 package pcapng
 
-import scodec.bits._
+import pcap._
 import scodec.Codec
+import scodec.bits._
 import scodec.codecs._
 
-case class InterfaceDescriptionBlock(length: Length, bytes: ByteVector) extends BodyBlock
+case class InterfaceDescriptionBlock(
+    length: Length,
+    linkType: LinkType,
+    snapLen: Long,
+    bytes: ByteVector
+) extends BodyBlock
 
 object InterfaceDescriptionBlock {
 
   private def hexConstant(implicit ord: ByteOrdering) =
     orderDependent(hex"00000001", hex"01000000")
 
+  // format: off
   def codec(implicit ord: ByteOrdering): Codec[InterfaceDescriptionBlock] =
-    "IDB" | Block.ignoredCodec(hexConstant).as[InterfaceDescriptionBlock]
+    "IDB" | Block.codec(hexConstant) { length =>
+      ("LinkType" | guint16.xmap[LinkType](LinkType.fromInt, LinkType.toInt)) ::
+      ("Reserved" | ignore(16)) ::
+      ("SnapLen" | guint32) ::
+      ("Block Bytes" | bytes(length.toLong.toInt - 20))
+    }.dropUnits.as[InterfaceDescriptionBlock]
+  // format: on
 }
diff --git a/protocols/shared/src/test/scala/fs2/protocols/PcapNgExample.scala b/protocols/shared/src/test/scala/fs2/protocols/PcapNgExample.scala
index 2cbffaeb84..78279afb3d 100644
--- a/protocols/shared/src/test/scala/fs2/protocols/PcapNgExample.scala
+++ b/protocols/shared/src/test/scala/fs2/protocols/PcapNgExample.scala
@@ -27,11 +27,12 @@ import fs2.interop.scodec.StreamDecoder
 import fs2.io.file.{Files, Path}
 import fs2.protocols.pcapng.{BodyBlock, DummyBlock, SectionHeaderBlock}
 import scodec.Decoder
+import cats.syntax.all._
 
 object PcapNgExample extends IOApp.Simple {
 
   def run: IO[Unit] =
-    decode.compile.count.flatMap(IO.println)
+    decode.compile.toList.flatMap(_.traverse_(IO.println))
 
   private def byteStream: Stream[IO, Byte] =
     Files[IO].readAll(Path("/Users/anikiforov/pcapng/many_interfaces.pcapng"))
diff --git a/protocols/shared/src/test/scala/fs2/protocols/pcapng/BlockTest.scala b/protocols/shared/src/test/scala/fs2/protocols/pcapng/BlockTest.scala
index 0b2c158935..a8d09c6bee 100644
--- a/protocols/shared/src/test/scala/fs2/protocols/pcapng/BlockTest.scala
+++ b/protocols/shared/src/test/scala/fs2/protocols/pcapng/BlockTest.scala
@@ -22,6 +22,7 @@
 package fs2.protocols
 package pcapng
 
+import fs2.protocols.pcap.LinkType.Ethernet
 import scodec.Attempt.Successful
 import scodec.DecodeResult
 import scodec.bits.ByteOrdering.LittleEndian
@@ -92,10 +93,10 @@ private object BlockTest {
     object Interface {
       val header = hex"01000000"
       val length = hex"20000000"
-      val nonParsed = hex"01000000ffff0000090001000600000000000000"
-      val bytes = header ++ length ++ nonParsed ++ length
-
-      val expected = InterfaceDescriptionBlock(Length(length), nonParsed)
+      val parsed = hex"01000000ffff0000"
+      val nonParsed = hex"090001000600000000000000"
+      val bytes = header ++ length ++ parsed ++ nonParsed ++ length
+      val expected = InterfaceDescriptionBlock(Length(length), Ethernet, 65535, nonParsed)
     }
 
     val enhancedHeader = hex"06000000"