unikernel/duniverse/mirage-crypto/ec/gen_tables/dune

@@ -0,0 +1,4 @@
+(include_subdirs no)
+(executable
+  (name gen_tables)
+  (libraries mirage_crypto_ec))

unikernel/duniverse/mirage-crypto/ec/gen_tables/gen_tables.ml

@@ -0,0 +1,112 @@
+open Format
+
+let print_header name =
+  printf
+    {|
+/*
+      Pre-computed %d-bit multiples of the generator point G for the curve %s,
+      used for speeding up its scalar multiplication in point_operations.h.
+
+      Generated by %s
+*/|}
+    Sys.word_size name Sys.argv.(0)
+
+let pp_array elem_fmt fmt arr =
+  let fout = fprintf fmt in
+  let len = Array.length arr in
+  fout "@[<2>{@\n";
+  for i = 0 to len - 1 do
+    elem_fmt fmt arr.(i);
+    if i < len - 1 then printf ",@ " else printf ""
+  done;
+  fout "@]@,}"
+
+let div_round_up a b = (a / b) + if a mod b = 0 then 0 else 1
+
+let pp_string_words ~wordsize fmt str =
+  assert (String.length str * 8 mod wordsize = 0);
+  let limbs = String.length str * 8 / wordsize in
+  (* Truncate at the beginning (little-endian) *)
+  let bytes = Bytes.unsafe_of_string str in
+  (* let bytes = rev_str_bytes str in *)
+  fprintf fmt "@[<2>{@\n";
+  for i = 0 to limbs - 1 do
+    let index = i * (wordsize / 8) in
+    (if wordsize = 64 then
+       let w = Bytes.get_int64_le bytes index in
+       fprintf fmt "%#016Lx" w
+     else
+       let w = Bytes.get_int32_le bytes index in
+       fprintf fmt "%#08lx" w);
+    if i < limbs - 1 then printf ",@ " else printf ""
+  done;
+  fprintf fmt "@]@,}"
+
+let check_shape tables =
+  let fe_len = String.length tables.(0).(0).(0) in
+  let table_len = fe_len * 2 in
+  assert (Array.length tables = table_len);
+  Array.iter
+    (fun x ->
+      assert (Array.length x = 15);
+      Array.iter
+        (fun x ->
+          assert (Array.length x = 3);
+          Array.iter (fun x -> assert (String.length x = fe_len)) x)
+        x)
+    tables
+
+let print_tables tables ~wordsize =
+  let fe_len = String.length tables.(0).(0).(0) in
+  printf "@[<2>static WORD generator_table[%d][15][3][LIMBS] = @," (fe_len * 2);
+  pp_array
+    (pp_array (pp_array (pp_string_words ~wordsize)))
+    std_formatter tables;
+  printf "@];@,"
+
+let print_toplevel name wordsize (module P : Mirage_crypto_ec.Dh_dsa) =
+  let tables = P.Dsa.Precompute.generator_tables () in
+  assert (wordsize = Sys.word_size);
+  check_shape tables;
+  print_header name;
+  if wordsize = 64 then
+    printf
+      "@[<v>#ifndef ARCH_64BIT@,\
+       #error \"Cannot use 64-bit tables on a 32-bit architecture\"@,\
+       #endif@,\
+       @]"
+  else
+    printf
+      "@[<v>#ifdef ARCH_64BIT@,\
+       #error \"Cannot use 32-bit tables on a 64-bit architecture\"@,\
+       #endif@,\
+       @]";
+  print_tables ~wordsize tables
+
+let curves =
+  Mirage_crypto_ec.
+    [
+      ("p256", (module P256 : Dh_dsa));
+      ("p384", (module P384));
+      ("p521", (module P521));
+    ]
+
+let usage () =
+  printf "Usage: gen_tables [%a] [64 | 32]@."
+    (pp_print_list
+       ~pp_sep:(fun fmt () -> pp_print_string fmt " | ")
+       pp_print_string)
+    (List.map fst curves)
+
+let go =
+  let name, curve, wordsize =
+    try
+      let name, curve =
+        List.find (fun (name, _) -> name = Sys.argv.(1)) curves
+      in
+      (name, curve, int_of_string Sys.argv.(2))
+    with _ ->
+      usage ();
+      exit 1
+  in
+  print_toplevel name wordsize curve