From 9525c64917b5263607997813a8139bb9503df33d Mon Sep 17 00:00:00 2001
From: Mylloon <kennel.anri@tutanota.com>
Date: Mon, 19 Jun 2023 21:52:39 +0200
Subject: [PATCH] WIP: parse dns packet

---
 bin/main.ml     | 10 +++-------
 lib/debug.ml    | 12 ++++++++++++
 lib/response.ml | 26 +++++++++++++++++++++-----
 lib/types.ml    |  8 ++++++++
 4 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/bin/main.ml b/bin/main.ml
index aa85030..d062677 100644
--- a/bin/main.ml
+++ b/bin/main.ml
@@ -1,12 +1,8 @@
 open Dnstoy
 
 let () =
-  let response = Network.send_request "8.8.8.8" "www.example.com" in
+  let response = Network.send_request "8.8.8.8" "www.mylloon.fr" in
   print_endline (Utils.get_bytecode response);
-  let reader, dns_header = Response.parse_header { data = response; pointer = 0 } in
-  let reader', dns_question = Response.parse_question reader in
-  let dns_record = Response.parse_record reader' in
-  Debug.print_dns_header dns_header;
-  Debug.print_dns_question dns_question;
-  Debug.print_dns_record dns_record
+  let dns_packet = Response.parse_dns_packet response in
+  print_endline (Debug.dns_packet dns_packet)
 ;;
diff --git a/lib/debug.ml b/lib/debug.ml
index 1b241ee..8fe99c3 100644
--- a/lib/debug.ml
+++ b/lib/debug.ml
@@ -27,3 +27,15 @@ let dns_record (record : Types.dns_record) =
     record.ttl
     (Utils.get_bytecode ~json:true record.data)
 ;;
+
+let dns_packet (record : Types.dns_packet) =
+  let list fn l = String.concat ", " (List.map (fun el -> fn el) l) in
+  Printf.sprintf
+    "{ \"header\": %s, \"questions\": [%s], \"answers\": [%s], \"authorities\": [%s], \
+     \"additionals\": [%s] }"
+    (dns_header record.header)
+    (list dns_question record.questions)
+    (list dns_record record.answers)
+    (list dns_record record.authorities)
+    (list dns_record record.additionals)
+;;
diff --git a/lib/response.ml b/lib/response.ml
index 0cb7144..ea031ca 100644
--- a/lib/response.ml
+++ b/lib/response.ml
@@ -47,10 +47,26 @@ and decode_compressed_name reader length =
 let parse_record reader =
   let name, offset_name = decode_name reader in
   let data = bytes_forward reader.data (offset_name + reader.pointer) in
-  { name
-  ; type_ = unpack_short_be data 0
-  ; class_ = unpack_short_be data 2
-  ; ttl = unpack_int_be data 4
-  ; data = Bytes.sub data 10 (unpack_short_be data 8)
+  let data_len = unpack_short_be data 8 in
+  let record_len = 10 in
+  ( { reader with pointer = reader.pointer + offset_name + record_len + data_len }
+  , { name
+    ; type_ = unpack_short_be data 0
+    ; class_ = unpack_short_be data 2
+    ; ttl = unpack_int_be data 4
+    ; data = Bytes.sub data record_len data_len
+    } )
+;;
+
+let parse_dns_packet data =
+  let reader, dns_header = parse_header { data; pointer = 0 } in
+  (* Quid du pointeur du reader, pas récupéré à chaque itération... *)
+  { header = dns_header
+  ; questions = List.init dns_header.num_questions (fun _ -> snd (parse_question reader))
+  ; answers = List.init dns_header.num_answers (fun _ -> snd (parse_record reader))
+  ; authorities =
+      List.init dns_header.num_authorities (fun _ -> snd (parse_record reader))
+  ; additionals =
+      List.init dns_header.num_additionals (fun _ -> snd (parse_record reader))
   }
 ;;
diff --git a/lib/types.ml b/lib/types.ml
index 0406bbe..6d8059b 100644
--- a/lib/types.ml
+++ b/lib/types.ml
@@ -25,3 +25,11 @@ type dns_record =
   ; ttl : int
   ; data : bytes
   }
+
+type dns_packet =
+  { header : dns_header
+  ; questions : dns_question list
+  ; answers : dns_record list
+  ; authorities : dns_record list
+  ; additionals : dns_record list
+  }