From bb960a900d697c636947c788ff89306639c904a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Dimitrov?= <peterdmv@erlang.org>
Date: Mon, 4 Jun 2018 17:02:20 +0200
Subject: ssl: Add new API function suite_to_str/1

Add new API function for converting cipher suite maps
to their textual representation.

Change-Id: I43681930b38e0f3bdb4dfccbf9e8895aa2d6a281
---
 lib/ssl/src/ssl.erl        | 12 +++++++++++-
 lib/ssl/src/ssl_cipher.erl | 28 +++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

(limited to 'lib/ssl/src')

diff --git a/lib/ssl/src/ssl.erl b/lib/ssl/src/ssl.erl
index a7b4ec2bf7..1e3b441e3c 100644
--- a/lib/ssl/src/ssl.erl
+++ b/lib/ssl/src/ssl.erl
@@ -55,7 +55,7 @@
          format_error/1, renegotiate/1, prf/5, negotiated_protocol/1, 
 	 connection_information/1, connection_information/2]).
 %% Misc
--export([handle_options/2, tls_version/1, new_ssl_options/3]).
+-export([handle_options/2, tls_version/1, new_ssl_options/3, suite_to_str/1]).
 
 -deprecated({ssl_accept, 1, eventually}).
 -deprecated({ssl_accept, 2, eventually}).
@@ -772,6 +772,16 @@ tls_version({3, _} = Version) ->
 tls_version({254, _} = Version) ->
     dtls_v1:corresponding_tls_version(Version).
 
+
+%%--------------------------------------------------------------------
+-spec suite_to_str(ssl_cipher:erl_cipher_suite()) -> string().
+%%
+%% Description: Return the string representation of a cipher suite.
+%%--------------------------------------------------------------------
+suite_to_str(Cipher) ->
+    ssl_cipher:suite_to_str(Cipher).
+
+
 %%%--------------------------------------------------------------
 %%% Internal functions
 %%%--------------------------------------------------------------------
diff --git a/lib/ssl/src/ssl_cipher.erl b/lib/ssl/src/ssl_cipher.erl
index 3f8b9a8a9b..c5b5b76f05 100644
--- a/lib/ssl/src/ssl_cipher.erl
+++ b/lib/ssl/src/ssl_cipher.erl
@@ -43,7 +43,7 @@
          filter/3, filter_suites/1, filter_suites/2,
 	 hash_algorithm/1, sign_algorithm/1, is_acceptable_hash/2, is_fallback/1,
 	 random_bytes/1, calc_mac_hash/4,
-         is_stream_ciphersuite/1]).
+         is_stream_ciphersuite/1, suite_to_str/1]).
 
 -export_type([cipher_suite/0,
 	      erl_cipher_suite/0, old_erl_cipher_suite/0, openssl_cipher_suite/0,
@@ -1877,6 +1877,32 @@ suite(#{key_exchange := dhe_rsa,
         prf := sha256}) ->
     ?TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256.
 
+
+%%--------------------------------------------------------------------
+-spec suite_to_str(erl_cipher_suite()) -> string().
+%%
+%% Description: Return the string representation of a cipher suite.
+%%--------------------------------------------------------------------
+suite_to_str(#{key_exchange := null,
+               cipher := null,
+               mac := null,
+               prf := null}) ->
+    "TLS_EMPTY_RENEGOTIATION_INFO_SCSV";
+suite_to_str(#{key_exchange := Kex,
+               cipher := Cipher,
+               mac := aead,
+               prf := PRF}) ->
+    "TLS_" ++ string:to_upper(atom_to_list(Kex)) ++
+        "_WITH_" ++  string:to_upper(atom_to_list(Cipher)) ++
+        "_" ++ string:to_upper(atom_to_list(PRF));
+suite_to_str(#{key_exchange := Kex,
+               cipher := Cipher,
+               mac := Mac}) ->
+    "TLS_" ++ string:to_upper(atom_to_list(Kex)) ++
+        "_WITH_" ++  string:to_upper(atom_to_list(Cipher)) ++
+        "_" ++ string:to_upper(atom_to_list(Mac)).
+
+
 %%--------------------------------------------------------------------
 -spec openssl_suite(openssl_cipher_suite()) -> cipher_suite().
 %%
-- 
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