From ec308c1fd4818b54ce8848c361598cc14fc2ea60 Mon Sep 17 00:00:00 2001
From: Mike Cifelli <admin@mike.cifelli.xyz>
Date: Sat, 16 Mar 2024 17:50:51 -0400
Subject: [PATCH] Read aead and next protocol as lists

---
 lib/chronoscope/nts/key_establishment.ex      | 39 +++++++++++++------
 .../nts/key_establishment_controller.ex       |  2 +-
 lib/chronoscope_web/router.ex                 |  4 +-
 3 files changed, 30 insertions(+), 15 deletions(-)
 rename lib/chronoscope_web/controllers/api/{ => v1}/nts/key_establishment_controller.ex (90%)

diff --git a/lib/chronoscope/nts/key_establishment.ex b/lib/chronoscope/nts/key_establishment.ex
index 0679aaa..fc00b51 100644
--- a/lib/chronoscope/nts/key_establishment.ex
+++ b/lib/chronoscope/nts/key_establishment.ex
@@ -5,6 +5,13 @@ defmodule Chronoscope.NTS.KeyEstablishment do
   @aead_algorithm_negotiation <<0x80, 0x04, 0x00, 0x04, 0x00, 0x1E, 0x00, 0x0F>>
   @end_of_message <<0x80, 0x00, 0x00, 0x00>>
 
+  @aead_alogorithms %{
+    15 => "AEAD_AES_SIV_CMAC_256",
+    30 => "AEAD_AES_128_GCM_SIV"
+  }
+
+  @next_protocols %{0 => "NTPv4"}
+
   def request() do
     @next_protocol_negotiation <> @aead_algorithm_negotiation <> @end_of_message
   end
@@ -27,7 +34,7 @@ defmodule Chronoscope.NTS.KeyEstablishment do
 
     do_parse_response(
       remaining,
-      Map.put(acc, :next_protocols, parse_next_protocol(next_protocols))
+      Map.put(acc, :next_protocols, parse_next_protocol_list(next_protocols))
     )
   end
 
@@ -38,7 +45,7 @@ defmodule Chronoscope.NTS.KeyEstablishment do
 
     do_parse_response(
       remaining,
-      Map.put(acc, :aead_algorithms, parse_aead_algorithm(aead_algorithms))
+      Map.put(acc, :aead_algorithms, parse_aead_algorithm_list(aead_algorithms))
     )
   end
 
@@ -62,24 +69,32 @@ defmodule Chronoscope.NTS.KeyEstablishment do
     do_parse_response(remaining, acc)
   end
 
-  defp parse_aead_algorithm([0x00, 0x0F]) do
-    "AEAD_AES_SIV_CMAC_256"
+  defp parse_aead_algorithm_list(aead_algorithms) do
+    do_parse_aead_algorithm_list(aead_algorithms, [])
   end
 
-  defp parse_aead_algorithm([0x00, 0x1E]) do
-    "AEAD_AES_128_GCM_SIV"
+  defp do_parse_aead_algorithm_list([], acc) do
+    acc
   end
 
-  defp parse_aead_algorithm(_aead_algorithm) do
-    "UNKNOWN"
+  defp do_parse_aead_algorithm_list([high, low | rest], acc) do
+    @aead_alogorithms
+    |> Map.get(combine_octets(high, low), "UNKNOWN")
+    |> then(&do_parse_aead_algorithm_list(rest, [&1 | acc]))
   end
 
-  defp parse_next_protocol([0x00, 0x00]) do
-    "NTPv4"
+  defp parse_next_protocol_list(next_protocols) do
+    do_parse_next_protocol_list(next_protocols, [])
   end
 
-  defp parse_next_protocol(_next_protocol) do
-    "UNASSIGNED"
+  defp do_parse_next_protocol_list([], acc) do
+    acc
+  end
+
+  defp do_parse_next_protocol_list([high, low | rest], acc) do
+    @next_protocols
+    |> Map.get(combine_octets(high, low), "UNASSIGNED")
+    |> then(&do_parse_aead_algorithm_list(rest, [&1 | acc]))
   end
 
   # todo parse server/port information
diff --git a/lib/chronoscope_web/controllers/api/nts/key_establishment_controller.ex b/lib/chronoscope_web/controllers/api/v1/nts/key_establishment_controller.ex
similarity index 90%
rename from lib/chronoscope_web/controllers/api/nts/key_establishment_controller.ex
rename to lib/chronoscope_web/controllers/api/v1/nts/key_establishment_controller.ex
index 487ecf4..679d8ec 100644
--- a/lib/chronoscope_web/controllers/api/nts/key_establishment_controller.ex
+++ b/lib/chronoscope_web/controllers/api/v1/nts/key_establishment_controller.ex
@@ -1,4 +1,4 @@
-defmodule ChronoscopeWeb.API.NTS.KeyEstablishmentController do
+defmodule ChronoscopeWeb.API.V1.NTS.KeyEstablishmentController do
   use ChronoscopeWeb, :controller
 
   require Logger
diff --git a/lib/chronoscope_web/router.ex b/lib/chronoscope_web/router.ex
index 03d181f..9898051 100644
--- a/lib/chronoscope_web/router.ex
+++ b/lib/chronoscope_web/router.ex
@@ -20,10 +20,10 @@ defmodule ChronoscopeWeb.Router do
     get "/", PageController, :home
   end
 
-  scope "/api", ChronoscopeWeb.API do
+  scope "/api/v1/nts", ChronoscopeWeb.API.V1.NTS do
     pipe_through :api
 
-    get "/key-exchange", NTS.KeyEstablishmentController, :get
+    get "/key-exchange", KeyEstablishmentController, :get
   end
 
   # Enable LiveDashboard and Swoosh mailbox preview in development