Icmp echo reply serialization

src/Packets/L3.hs

@@ -75,6 +75,13 @@ instance Binary IcmpPacket where
     putWord16be . unIcmpSqnum $ icmpSqnum
     putByteString payload
 
-  put _ = undefined
+  put (IcmpEchoResponse icmpId icmpSqnum payload) = putByteString $ fillIcmpChecksum . B.toStrict . runPut $ do
+    put IcmpTypeEchoResponse
+    putWord8 0 -- ICMP Code
+    putWord16be 0 -- Fill later
+    putWord16be . unIcmpId $ icmpId
+    putWord16be . unIcmpSqnum $ icmpSqnum
+    putByteString payload
+
   get = undefined
 

test/Test/Packets/L3.hs

@@ -20,7 +20,8 @@ tests = testGroup "L3" [ unitTests]
 
 unitTests :: TestTree
 unitTests = testGroup "Unit tests" [ testIpChecksum
-                                   , testSerializeEchoRequest ]
+                                   , testSerializeEchoRequest
+                                   , testSerializeEchoResponse ]
 
 testIpChecksum :: TestTree
 testIpChecksum = testCase "ipChecksum case 1" $ do
@@ -42,4 +43,15 @@ testSerializeEchoRequest = testCase "serialize IcmpEchoRequest" $ do
   let icmp = IcmpEchoRequest (IcmpId 40402) (IcmpSqnum 2) payload
   (B.toStrict . encode) icmp @=? testIcmp
 
+testSerializeEchoResponse :: TestTree
+testSerializeEchoResponse = testCase "serialize IcmpEchoResponse" $ do
+  let payload = B.pack [
+        0x1c, 0x25, 0x31, 0x65, 0x00, 0x00, 0x00, 0x00,
+        0x72, 0x51, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+        0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+        0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37
+        ]
+  let testIcmp = B.pack [ 0x00, 0x00, 0xe0, 0x7c, 0x9d, 0xd2, 0x00, 0x02] <> payload
+  let icmp = IcmpEchoResponse (IcmpId 40402) (IcmpSqnum 2) payload
+  (B.toStrict . encode) icmp @=? testIcmp