From 121e93e0a091ffef8ed577ef4b15cfa5603c9853 Mon Sep 17 00:00:00 2001
From: Mylloon <kennel.anri@tutanota.com>
Date: Wed, 14 Jun 2023 18:52:17 +0200
Subject: [PATCH] detect the compressed stuff, actually returns bad data, but
 at least it doesnt crash, add the python code of the guide too so ik what i
 need to do

---
 lib/response.ml | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/lib/response.ml b/lib/response.ml
index 9fa0dbf..60f3d6f 100644
--- a/lib/response.ml
+++ b/lib/response.ml
@@ -25,6 +25,10 @@ and decode_name_simple reader =
     let length = int_of_char (Bytes.get reader.data (reader.pointer + pos)) in
     if length = 0
     then 1, parts
+    else if length land 0b1100_0000 <> 0
+    then (
+      let decoded_name = decode_compressed_name reader length in
+      length + 1, decoded_name :: parts)
     else (
       let part = Bytes.sub_string reader.data (reader.pointer + pos + 1) length in
       let last_length, parts' = read_parts (parts @ [ part ]) (pos + 1 + length) in
@@ -32,10 +36,40 @@ and decode_name_simple reader =
   in
   let offset, parts = read_parts [] 0 in
   String.to_bytes (String.concat "." parts), offset
+
+(*
+---
+def decode_compressed_name(length, reader):
+    pointer_bytes = bytes([length & 0b0011_1111]) + reader.read(1)
+    pointer = struct.unpack("!H", pointer_bytes)[0]
+    current_pos = reader.tell()
+    reader.seek(pointer)
+    result = decode_name(reader)
+    reader.seek(current_pos)
+    return result
+---
+*)
+and decode_compressed_name _reader _length =
+  (* TODO *)
+  String.empty
 ;;
 
-let parse_record _reader =
-  let name, _offset_name = Bytes.empty, 0 (* decode_name_simple reader *) in
+(*
+---
+def parse_record(reader):
+    name = decode_name_simple(reader)
+    # the the type, class, TTL, and data length together are 10 bytes (2 + 2 + 4 + 2 = 10)
+    # so we read 10 bytes
+    data = reader.read(10)
+    # HHIH means 2-byte int, 2-byte-int, 4-byte int, 2-byte int
+    type_, class_, ttl, data_len = struct.unpack("!HHIH", data)
+    data = reader.read(data_len)
+    return DNSRecord(name, type_, class_, ttl, data)
+---
+*)
+let parse_record reader =
+  let name, _offset_name = decode_name_simple reader in
+  (* TODO *)
   let type_, class_, ttl, data = 0, 0, 0, Bytes.empty in
   { name; type_; class_; ttl; data }
 ;;