This repository has been archived on 2024-05-23. You can view files and clone it, but cannot push or open issues or pull requests.
dns-toy/lib/response.ml
2023-06-14 16:34:49 +02:00

33 lines
1.1 KiB
OCaml

open Types
open Utils
let parse_header reader =
let max_size = 6 in
match List.init max_size (fun offset -> unpack_short_be reader (offset * 2)) with
| [ id; flags; num_questions; num_answers; num_authorities; num_additionals ] ->
( bytes_forward reader (max_size * 2)
, { id; flags; num_questions; num_answers; num_authorities; num_additionals } )
| _ -> failwith "Invalid number of fields"
;;
let decode_name_simple reader =
let rec read_parts parts pos =
let length = int_of_char (Bytes.get reader pos) in
if length = 0
then 1, parts
else (
let part = Bytes.sub_string reader (pos + 1) length in
let last_length, parts' = read_parts (parts @ [ part ]) (pos + 1 + length) in
last_length + length + 1, parts')
in
let offset, parts = read_parts [] 0 in
bytes_forward reader offset, String.concat "." parts
;;
let parse_question reader =
let reader', name_b = decode_name_simple reader in
let name = String.to_bytes name_b in
match List.init 2 (fun offset -> unpack_short_be reader' (offset * 2)) with
| [ type_; class_ ] -> { name; type_; class_ }
| _ -> failwith "Invalid number of fields"
;;