From caabc153954ae8230f40f7bd09577b258619ef31 Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Wed, 14 Mar 2018 17:24:48 +0100
Subject: [PATCH 1/2] sys/random: provide generic random_bytes()

---
 sys/random/Makefile             |  2 +-
 sys/random/{seed.c => random.c} | 15 +++++++++++++++
 sys/random/tinymt32.c           | 30 ------------------------------
 3 files changed, 16 insertions(+), 31 deletions(-)
 rename sys/random/{seed.c => random.c} (71%)

diff --git a/sys/random/Makefile b/sys/random/Makefile
index 1068de18a3..4e66ead042 100644
--- a/sys/random/Makefile
+++ b/sys/random/Makefile
@@ -1,4 +1,4 @@
-SRC := seed.c
+SRC := random.c
 
 BASE_MODULE := prng
 SUBMODULES := 1
diff --git a/sys/random/seed.c b/sys/random/random.c
similarity index 71%
rename from sys/random/seed.c
rename to sys/random/random.c
index b53d4ff814..dc5e6cf38d 100644
--- a/sys/random/seed.c
+++ b/sys/random/random.c
@@ -39,3 +39,18 @@ void auto_init_random(void)
     DEBUG("random: using seed value %u\n", (unsigned)seed);
     random_init(seed);
 }
+
+void random_bytes(uint8_t *target, size_t n)
+{
+    uint32_t random;
+    uint8_t *random_pos = (uint8_t*)&random;
+    unsigned _n = 0;
+
+    while (n--) {
+        if (! (_n++ & 0x3)) {
+            random = random_uint32();
+            random_pos = (uint8_t *) &random;
+        }
+        *target++ = *random_pos++;
+    }
+}
diff --git a/sys/random/tinymt32.c b/sys/random/tinymt32.c
index 8442457e96..9537d7cd7d 100644
--- a/sys/random/tinymt32.c
+++ b/sys/random/tinymt32.c
@@ -44,36 +44,6 @@ uint32_t random_uint32(void)
     return tinymt32_generate_uint32(&_random);
 }
 
-void random_bytes(uint8_t *buf, size_t size)
-{
-    size_t iter = size;
-    size_t diff = _align(buf) - buf;
-    uint32_t tmp;
-
-    /* Fill first <4 unaligned bytes */
-    if (diff) {
-        tmp = tinymt32_generate_uint32(&_random);
-        if (diff > size) {
-            diff = size;
-        }
-        memcpy(buf, &tmp, diff);
-        iter -= diff;
-    }
-
-    /* Fill aligned bytes */
-    while (iter >= sizeof(uint32_t)) {
-        *((uint32_t *) buf) = tinymt32_generate_uint32(&_random);
-        buf += sizeof(uint32_t);
-        iter -= sizeof(uint32_t);
-    }
-
-    /* Fill last bytes */
-    if (iter) {
-        tmp = tinymt32_generate_uint32(&_random);
-        memcpy(buf, &tmp, iter);
-    }
-}
-
 void random_init_by_array(uint32_t init_key[], int key_length)
 {
     tinymt32_init_by_array(&_random, init_key, key_length);

From 9f3aa366a3fdeb5e021caf7de979e24e125d013d Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Wed, 14 Mar 2018 18:01:12 +0100
Subject: [PATCH 2/2] pkg: tweetnacl: use random_bytes()

---
 pkg/tweetnacl/Makefile.dep      |  1 +
 pkg/tweetnacl/src/randombytes.c | 13 ++-----------
 2 files changed, 3 insertions(+), 11 deletions(-)
 create mode 100644 pkg/tweetnacl/Makefile.dep

diff --git a/pkg/tweetnacl/Makefile.dep b/pkg/tweetnacl/Makefile.dep
new file mode 100644
index 0000000000..8030144a9a
--- /dev/null
+++ b/pkg/tweetnacl/Makefile.dep
@@ -0,0 +1 @@
+USEMODULE+=random
diff --git a/pkg/tweetnacl/src/randombytes.c b/pkg/tweetnacl/src/randombytes.c
index 54a5e2b315..853a26511a 100644
--- a/pkg/tweetnacl/src/randombytes.c
+++ b/pkg/tweetnacl/src/randombytes.c
@@ -15,15 +15,6 @@
 
 void randombytes(uint8_t *target, uint64_t n)
 {
-    uint32_t random;
-    uint8_t *random_pos = (uint8_t*)&random;
-    unsigned _n = 0;
-
-    while (n--) {
-        if (! (_n++ & 0x3)) {
-            random = random_uint32();
-            random_pos = (uint8_t *) &random;
-        }
-        *target++ = *random_pos++;
-    }
+    /* tweetnacl needs uint64_t as "n" parameter, random provides uint32 */
+    random_bytes(target, n);
 }